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Enchytraeus andrasi sp. nov. urn:lsid:zoobank.org:act: 5E2BFD02-E8F8-4689-95F1-57E3A7B01A61 Figs 1C–D, 4, Tables 1–2 Diagnosis (1) Body length 11–14 mm (in vivo), segment number 29–34; (2) chaetae maximum 3 per bundle, straight with ental hook; (3) clitellum in XII–XIII, hyalocytes and granulocytes irregularly arranged dorsally and laterally, ventrally absent between the male lip-like folds; (4) four pairs of nephridia preclitellarly; (5) all pharyngeal glands connected dorsally with ventral lobes, the third pair may be free; (6) dorsal blood vessel origin from XIV, blood colourless; (7) sperm funnel cylindrical, 380–580 μm long, 3–5 × as long as wide (in vivo); (8) vasa deferentia uniform, 24–25 μm wide with 8 μm thick wall (fixed), ciliated, not extending beyond XIII; (9) male glands multiple: one large rounded primary bulb, diameter 50–70 μm (fixed), and many smaller secondary glands; (10) spermathecal ectal duct (50–85 μm long, fixed) covered with gland cells, ampulla irregularly sac-like, about 100–106 μm wide with one large diverticulum (80–100 μm long, fixed), connecting with oesophagus; (11) more small mature eggs present at a time. Etymology Named in the honour of the brother of Klára Dózsa-Farkas, András Dózsa-Farkas, who collected the sample with this species. Material examined Holotype ITALY • last 14 segments, 3.4 mm used for DNA analysis (No. 1386, ID number); Ligurian Sea, Castiglione seashore, decaying seagrass debris; 42°45′56.0″ N, 10°52′51.0″ E; 13 Dec. 2019; András and Kinga Dózsa-Farkas leg.; slide 2871, En.3; ELTE. Paratypes ITALY • 1 spec., last 9 segments, 1.65 mm used for DNA analysis (No. 1390, ID number); same collection data as for holotype; slide 2870, P.144.1; ELTE • 1 spec., last 9 segments, 1.65 mm used for DNA analysis (No. 1391, ID number); same collection data as for holotype; slide 2873, P.144.2; ELTE. Description MEASUREMENTS. Medium-sized to large specimens. Holotype 14.3 mm long, 470 μm wide at VIII and 600 μm at clitellum in vivo, 9.3 mm long, 330 μm wide at VIII and 420 μm at clitellum, when fixed, 41 segments. Body length of paratypes 11–12 mm, width 430–450 μm at VIII and 550–680 μm at clitellum, in vivo. Length of fixed specimens 6.7–8.1 mm, width 420 μm at VIII and 470–580 μm at clitellum. Length of the first 12 segments 2.5–2.6 mm, after fixation. Segment number 29–34. CHAETAE. Chaetal formula: 3–2,3:3–2,3. Chaetae straight with ental hook, about equal in size within bundle, 60–62 μm × 4 μm preclitellarly and 67–75 μm × 4–5 μm posteriorly. Often 2–3 surplus chaetae near bundles (Fig. 4B). Chaetae in XII absent ventrally, but present laterally, 2 per bundle. HEAD PORE. At 0/I. EPIDERMAL GLANDS. Inconspicuous. CLITELLUM. In XII–XIII, hyalocytes and granulocytes irregularly arranged dorsally and laterally (Fig. 4C), ventrally absent between male lip-like folds (Fig. 4E). Before and behind some glands but few. BRAIN (Fig. 4A). About 1.8–2 × as long as wide, truncate posteriorly, sides slightly merging anteriad. OESOPHAGEAL APPENDAGES. Pair of blind-ending tubes. In two specimens all primary pharyngeal glands connected dorsally, with ventral lobes (Fig. 4D), but in third specimen last pair free dorsally. DORSAL BLOOD VESSEL. From XIV, blood colourless. Anterior bifurcation in I. NEPHRIDIA. Four pairs of preclitellar nephridia from 6/ 7–9 /10, anteseptale funnel only, postseptale bulged, short efferent duct, originating postero-ventrally (Fig. 4F). COELOMOCYTES. Oval, texture granulated, about 18–25 μm long, in vivo. No shining, hyaline corpuscles. SUBNEURAL GLANDS. Absent. SPERM SACS. Two paired large lobes of sperm sacs, filling the coelom of X–XI. Testes and sperm funnels in XI, ovaries, male pores and glands in XII. SPERM FUNNELS. Large, 380–580 μm long, 3–5 × as long as wide in vivo (235–330 μm long and 2–2.5 × as long as wide, fixed). Collar slightly narrower than funnel body (Fig. 4H). Vasa deferentia long, irregularly coiled in XII–XIII, about 24–25 μm wide with 8 μm thick wall (fixed), ciliated (Fig. 4G, I). SPERMATOZOA. Not measurable, heads about 21–36 μm, in vivo. MALE COPULATORY ORGANS. Male glands multiple: one larger rounded primary bulb (diameter 50–70 μm, fixed) near male pore, and many smaller (32–78 μm long and 18–24 μm wide, fixed) secondary glands. Glands arranged roughly in semicircle around male pore and primary bulb (diameter 180–250 μm, fixed) (Fig. 4J). Male pores covered by lip-like folds (about 80 μm wide), recess present. SPERMATHECAE (Figs 1C–D, 4K). With short ectal duct (50–85 μm long, fixed), covered with gland cells (50–75 μm widely in vivo and fixed equally), canal 4–6 μm wide. Ampulla irregularly sac-like, about 100–106 μm wide, heads of spermatozoa embedded in wall of ampulla. Ampulla with one large diverticulum (80–140 μm long, 40–68 μm wide, fixed) (Fig. 1C), in one case ampulla also with small diverticula-like protrusions (Figs 1D, 4K). Ental duct short and opens into oesophagus separately. More small mature eggs present at a time (Fig. 4I). Differential diagnosis In the new species, like as in four of the species in the E. albidus complex (E. albidus s. str., E. moebii, E. polatdemiri and E. irregularis of which sequences are available, the vasa deferentia approximately uniform and ciliated throughout. The principal differences are that the spermathecal ampullae have diverticula in the new species but neither E. moebii nor E. polatdemiri have it. Besides E. moebii is much larger than the new species (body length 25–35 mm with segment number 60–74 vs 6.7–9.3 mm 29–41) and has more chaetae in ventral bundle (4–5 vs 3). Although in E. irregularis the spermatheca has also diverticulum and the maximum number of chaetae is 3, but E. irregularis is larger than the new species (length 9–13 mm with segment number 47–76), and the blood is pink (in E. andrasi sp. nov. colourless) and has extra copulatory glands. Morphologically, E. albidus s. str. is most similar to the new species taking, the form of the spermatheca into consideration, but differs from it in size (10– 13 mm with 58–69 segments vs 6.7–9.3 mm and 29–41 segments) and in the maximum number of chaetae (4–5 vs 3) and the sperm duct extends into XIV–XX (vs only in XII–XIII). The new species is also similar to E. andrasiformis sp. nov., with the morphological differences listed in the differential diagnosis of the latter species.As shown below, E. andrasi is clearly distinguished as separate from all other species by genetic data, which also give strong support for E. andrasi being most closely related to E. andrasiformis, described below. For similarities and differences of the species of Enchytraeus studied by us, see Table 2. Distribution and habitat Castiglione seashore, Ligurian Sea, Italy, decaying seagrass debris., Published as part of Nagy, Hajnalka, Dózsa-Farkas, Klára & Felföldi, Tamás, 2023, New insights into the Enchytraeus albidus complex (Annelida, Enchytraeidae), with the description of three new species from seashores in Italy and Croatia, pp. 107-145 in European Journal of Taxonomy 870 on pages 13-19, DOI: 10.5852/ejt.2023.870.2123, http://zenodo.org/record/7986633, {"references":["Erseus C., Klinth M. J., Rota E., Wit P. D., Gustafsson D. R. & Martinsson S. 2019. The popular model annelid Enchytraeus albidus is only one species in a complex of seashore white worms (Clitellata, Enchytraeidae). Organisms Diversity & Evolution 19: 105 - 133. https: // doi. org / 10.1007 / s 13127 - 019 - 00402 - 6","Arslan N., Timm T., Rojo V., Vizcaino A. & Schmelz R. M. 2018. A new species of Enchytraeus (Enchytraeidae, Oligochaeta) from the profundal of Lake Van, the world's largest soda lake (Turkey, East Anatolia). Zootaxa 4382 (2): 367 - 380. https: // doi. org / 10.11646 / zootaxa. 4382.2.8","Cejka B. 1913. Litorea krumbachi n. spec. n. gen. Ein Beitrag zur Systematik der Enchytraeiden. Zoologischer Anzeiger 17: 145 - 151.","Nielsen C. O. & Christensen B. 1961. The Enchytraeidae. Critical revision and taxonomy of European species. Supplement 1. Natura Jutlandica 10: 1 - 23.","Dozsa-Farkas K. 2019. Enchytraeids of Hungary (Annelida: Clitellata: Enchytraeidae). Pedozoologica Hungarica 7. Eotvos University Press, Budapest.","Henle F. G. J. 1837. Ueber Enchytraeus, eine neue Anneliden-Gattung. Archiv fur Anatomie, Physiologie und Wissenschaftliche Medicin 74 - 90.","Michaelsen W. 1885. Vorlaufige Mitteilungen uber Archenchytraeus Mobii n. sp. Zoologischer Anzeiger 8: 237 - 239."]}

Enchytraeus sp.2 from Svalbard Material examined SVALBARD • 7 specs; Kongsfjorden; ID 264 to 265, slide No. 2140 to 2141, 3039, 3217 to 3218; ELTE. Description Short description of fixed specimens: MEASUREMENTS. Body length 11–16 mm, segment number 55–66, 650–800 μm wide at clitellum. CHAETAE. Chaetal formula: 3,2–2:3(2)–2. Preclitellar chaetae 60–85 μm × 7 μm ventrally, 55–58 μm × 6 μm laterally, postclitellar chaetae 75–85 μm × 6 μm ventrally, and 58–75 μm × 6 μm laterally. DORSAL VESSEL. From XIII–XIV. SPERM SACS. Large sperm sacs, located in X–XI. SPERM FUNNEL. 376 μm long, about 3 × as long as wide, fixed. Sperm duct about the same wide in all length (20–25 μm wide). MALE COPULATORY ORGANS. Male glands multiple: one larger rounded primary bulb (diameter 75–85 μm) and numerous smaller glands. SPERMATHECAE. Ectal duct of spermatheca 62–90 μm long with large glands around orifice of duct. Ampulla spherical (diameter 120–140 μm) with one diverticulum (about 270 μm long), or 2–3 smaller diverticula (80–110 μm long). Additional specimens would be required for accurate description. Distribution and habitat Kongsfjorden, Svalbard, under a bird cliff ‘compost’ of bird excrements, mosses, vascular plants and nest material., Published as part of Nagy, Hajnalka, Dózsa-Farkas, Klára & Felföldi, Tamás, 2023, New insights into the Enchytraeus albidus complex (Annelida, Enchytraeidae), with the description of three new species from seashores in Italy and Croatia, pp. 107-145 in European Journal of Taxonomy 870 on page 31, DOI: 10.5852/ejt.2023.870.2123, http://zenodo.org/record/7986633

Enchytraeus sp.3 from Kerguelen Islands Material examined KERGUELEN ISLANDS • 5 specs; Ile Guillou Island; ID 260 to 261, slide No. 3035 to 3037; ELTE. Description Based on the few specimens in imperfect condition, Echytraeus sp.3 from Kerguelen Islands is very similar morphologically to E. albidus s. str. MEASUREMENTS. Body length 10–13 mm, segment number 44–54, 610–660 μm wide at clitellum, fixed. CHAETAE. Chaetal formula: 3–2,3:3,4–2,3. 87–95 μm × 8 μm in ventral bundles, 77–80 μm × 7.5 μm in lateral bundles preclitellarly and 77–80 μm × 7 μm in ventral bundles and 62–70 μm × 5 μm in lateral bundles posteriorly. DORSAL VESSEL. from XIII–XIV. COELOMOCYTES. 31–42 μm long. SPERM SACS. Large sperm sacs, located in X–XI. SPERM FUNNEL. 375–550 μm long, about 4 × as long as wide, fixed. SPERMATOZOA. About 60 μm long, heads 18 μm. Sperm duct about same wide in all length (23–30 μm wide). MALE COPULATORY ORGANS. Male glands multiple: one larger rounded primary bulb (80–100 μm, fixed) and numerous smaller glands. SPERMATHECAE. Ectal duct of spermatheca with glands around duct, not only at the orifice. Ampulla with one diverticulum (about 210 μm long, fixed). Distribution and habitat Guillou Island, Kerguelen Islands, under a small clump of Poa kerguelensis. Results of molecular analysis Results of molecular analysis corroborated that E. adrianensis sp. nov., E. andrasi sp. nov. and E. andrasiformis sp. nov. are new, distinct species, since the sequences obtained from the examined individuals clearly separated in the phylogenetic trees (Figs 10–12). Our study also provided new reference sequences for E. albidus s. str., E. irregularis, E. krumbachi, and it provided sequences for further unnamed taxa within the E. albidus group (E. sp.2 and E. sp.3). Enchytraeus andrasi sp. nov. and E. andrasiformis formed distinct lineages, they were placed outside the clade of the E. albidus complex in the phylogenetic trees. The p-distances between the COI sequences of E. andrasi and E. andrasiformis are 16.8–17.6%, the H3 distances between them are 3%. The COI distances between E. andrasi and the members of E. albidus complex (including E. adrianensis) are 15.9–20.6%, the H3 distances between them are 5.4–8.5%. The intraspecific COI distances between specimens of E. andrasi are 0–1.8%. There are no intraspecific differences between the H3 sequences of E. andrasi individuals. The COI distances between E. andrasiformis and the species of E. albidus complex (including E. adrianensis sp. nov.) are 15.6–20.3%, the H3 distances between them are 5.2–8.1%. Enchytraeus adrianensis and additional species missing from the study of Erséus et al. (2019), namely E. irregularis, E. sp.2 and E. sp.3 were placed inside the clade of the E. albidus complex. The COI distances between E. adrianensis and members of E. albidus complex are 12.8–17.8%, the H3 distances between them are 0.4–5.5%. There are no intraspecific differences between the COI and between the H3 sequences of specimens of E. adrianensis. Enchytraeus sp.2 and E. sp.3 formed one group on the gene trees. It is worth noting that the COI distance between E. sp.2 and E. sp.3 is very small (0.2%), while the H3 distance between them is bigger (2.5%), and comparable to interspecific differences in the rest of the H3 gene tree (Fig. 11). Enchytraeus adrianensis appeared as the sister group of E. krumbachi in the COI and H3 gene trees, and E. irregularis appeared as the sister group of E. sp.2 / sp.3 clade in both of the gene trees (Figs 10– 11). The COI distances between E. adrianensis and E. krumbachi are 12.9–13.4%, the H3 distances between them are low, 0.4–1.6%. The COI distances between E. irregularis and E. sp.2 / sp.3 clade are 12.2–12.9%, the H3 distances between them are 2.1–3.8%. According to the molecular analysis, our E. krumbachi individuals and E. cf. krumbachi CE1684 and CE1689 specimens belong to the same species. The intraspecific COI distances between our E. krumbachi and E. cf. krumbachi individuals are 0.7–3%, the intraspecific H3 distances between them are 0–0.8%. On the species tree (Fig. 12), the E. albidus complex formed a distinct clade with maximum posterior probability support and contains E. adrianensis, E. irregularis and E. sp.2 / sp.3, as in the gene trees. E. adrianensis sp. nov. appeared as the sister group of E. krumbachi, E. sp.2 / sp.3 appeared as the sister group of E. irregularis. Enchytraeus andrasi and E. andrasiformis were placed outside the E. albidus complex and they appeared there as sister groups of each other. E. andrasi and E. andrasiformis clustered with E. norvegicus Abrahamsen, 1969 on the species tree (Fig. 12) but with only low posterior probability support, and the latter species differs from the new species in many traits., Published as part of Nagy, Hajnalka, Dózsa-Farkas, Klára & Felföldi, Tamás, 2023, New insights into the Enchytraeus albidus complex (Annelida, Enchytraeidae), with the description of three new species from seashores in Italy and Croatia, pp. 107-145 in European Journal of Taxonomy 870 on pages 31-32, DOI: 10.5852/ejt.2023.870.2123, http://zenodo.org/record/7986633, {"references":["Erseus C., Klinth M. J., Rota E., Wit P. D., Gustafsson D. R. & Martinsson S. 2019. The popular model annelid Enchytraeus albidus is only one species in a complex of seashore white worms (Clitellata, Enchytraeidae). Organisms Diversity & Evolution 19: 105 - 133. https: // doi. org / 10.1007 / s 13127 - 019 - 00402 - 6"]}

Enchytraeus irregularis Nielsen & Christensen, 1961 Figs 1G, 9, Tables 1–2 Enchytraeus irregularis Nielsen & Christensen, 1961: 13. Enchytraeus irregularis – Hong & Dozsa-Farkas 2018: 81–85, figs. 2–4. Enchytraeus irregularis – Dózsa-Farkas K. 2019: 81–82, fig. 6.39.1 Material examined KOREA • 5 specs; Jeollabuk-do, Songcheon-dong; ID: 262, 906, slide 573 to 575; ELTE. HUNGARY • 5 specs; Érd; ID 946, slide 3029 to 3031, 3034 • 2 specs; Tiszalök, slide 2110 to 2111; ELTE. Description The species was described by Nielsen & Christensen (1961) from compost heap in the Botanical Garden of Copenhagen, Denmark. In 1987, Dózsa-Farkas found it in an earthworm-farm in Tiszalök (Hungary) and in 2016, in a sewage-sludge compost-bed in Érd (Hungary). In 2007, individuals of E. irregularis were collected from an earthworm breeding box in house (Korea, Jeollabuk-do) and a culture was made from these specimens. The results of the latter study were published in Hong & Dózsa-Farkas (2018). Schmelz & Collado (2010) proposed its synonymy with E. capitatus von Bülow, 1957, but Dózsa-Farkas (2019) disagreed with it. Now we were able to study these specimens using DNA sequencing, so all earlier specimens and some new specimens from Korea and Hungary were studied again morphologically. On the basis of the result of this new study, we give an additional description of this species. MEASUREMENTS. Body length 14–20 mm, width 540–700 μm at clitellum in vivo (length 9–13 mm and 530–880 μm wide, if fixed), segment number 47–66 (segment number 41–49 in Nielsen & Christensen 1961). Length of the first 12 segments 2.3–3.0 mm, after fixation. CHAETAE. Straight or slightly curved, formula of 3–2,3: 3–2,3,(4). CLITELLUM. Saddle-shaped, over XII–XIII (XIV), gland cells small, irregularly scattered (Fig. 9B). HEAD PORE. At 0/1. BRAIN. About 150 μm long, 1.6 × as long as wide in vivo, with one or two pairs of aggregations of refractile globules (Fig. 9A). OESOPHAGEAL APPENDAGES. Short, outline irregular, thin-walled with single central lumen. All three pairs of primary pharyngeal glands with connection dorsally and ventral lobes. DORSAL VESSEL. From XIV–XVI, blood faintly red, anterior bifurcation in peristomium (Fig. 9D). COELOMOCYTES. One type, only mucocytes, small, oval or elongate, pear-shaped, 20–29 μm long in vivo, filled with light granules (Fig. 9C). Shining hyaline corpuscles also occur but in few numbers. NEPHRIDIA. Four pairs of nephridia preclitellarly. SPERM SACS. Paired, well developed and lobed, located in IX–XI (Fig. 9G). SPERM FUNNELS (Fig. 9G). 415–730 μm long, 4–7 × as long as wide, about as long as the body diameter in vivo, (270–600 μm long, 2–4 × as long as wide, if fixed), collars slightly wider than funnel. SPERMATOZOA. About 80–100 μm long, heads about 30 μm in vivo, sperm ducts uniform, about 20 μm wide. MALE COPULATORY ORGANS. Male glands multiple with larger primary bulb (70–100 μm × 70–100 μm) and 6–8 narrower, long, glandular secondary glands (50–90 μm × 12–14 μm) around male pores (Fig. 9F–G). After male copulatory organs pair of oval or squarish glandular structure visible with subdivision (‘accessory sexual glands’) (150–250 μm long, 110–225 μm wide, about 100 μm high, fixed), without external orifice (Fig. 9F, H–I). Usually in XIII, directly before the ventral chaetal bundles. In one specimen, visible immediately before male copulatory organs, and in another specimen, where clitellum was from XII to XIV, this organ was found in XV and only on one side (slide no. 573). Now revised again under microscope, so Hong & Dózsa-Farkas (2018): 85 is not correct: “clitellum extended over XII–XV and accessory sexual gland found in XIV” (but correct caption of fig. 3g). In Nielsen & Christensen (1961), location of this organ in front of penial bulb and also in XIII ventrally. These organs mostly larger than male copulatory organ. SPERMATHECAE. Spermathecal ectal ducts (87–110 μm long), with distinct canals (5–8 μm wide) and ring of glands around ectal orifices. Length of glands about 55–75 μm (fixed). Length of duct without glands proximally 13–25 μm. Duct widens into ampulla proximally (diameter of ampullae about 75–130 μm), which again gradually tapers into short ental ducts, communicating separately with oesophagus. From ampullae anteriorly or laterally arises one large diverticulum (170–220 μm long in vivo, 100–200 μm fixed) filled with spermatozoa (Fig. 9K–L). 2–8 mature eggs at a time. Differential diagnosis The main differences between this species and the other species investigated by us are the pink blood, and the characteristic large extra sexual glands without external orifice. For similarities and differences of this species compared to other species of the E. albidus complex, see Table 2. Distribution and habitat Songcheon-dong, Jeollabuk-do, Korea, earthworm breeding box in house.Tiszalök, Hungary, earthworm-farm. Érd, Hungary, sewage-sludge compost bed. This species has unknown origin, only appeared in culture, it has not yet been found in the wild., Published as part of Nagy, Hajnalka, Dózsa-Farkas, Klára & Felföldi, Tamás, 2023, New insights into the Enchytraeus albidus complex (Annelida, Enchytraeidae), with the description of three new species from seashores in Italy and Croatia, pp. 107-145 in European Journal of Taxonomy 870 on pages 27-30, DOI: 10.5852/ejt.2023.870.2123, http://zenodo.org/record/7986633, {"references":["Nielsen C. O. & Christensen B. 1961. The Enchytraeidae. Critical revision and taxonomy of European species. Supplement 1. Natura Jutlandica 10: 1 - 23.","Hong Y. & Dozsa-Farkas K. 2018. New description of enchytraeid species (Clitellata: Enchytraeidae) from Korea. Journal of Species Research 7: 80 - 91. https: // doi. org / 10.12651 / JSR. 2018.7.1.080","Schmelz R. M. & Collado R. 2010. A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms 82: 1 - 176.","von Bulow T. 1957. Systematisch-autokologische Studien an eulitoralen Oligochaeten der Kimbrischen Halbinsel. Kieler Meeresforschungen 13: 96 - 116.","Dozsa-Farkas K. 2019. Enchytraeids of Hungary (Annelida: Clitellata: Enchytraeidae). Pedozoologica Hungarica 7. Eotvos University Press, Budapest."]}

Enchytraeus albidus Henle, 1837 s. str. Figs 1F, 6, Tables 1–2 Material examined HUNGARY • 16 specs; Budapest; ID 1300 to 1301, 1461 to 1462, slide 3012, 3013, 3016 to 3018, 3024, 3028, 3044 to 3048; ELTE. Description of new material We investigated a living population of E. albidus s. str. from the laboratory of Szent István University, Hungary, which was derived from the culture of ECT Oekotoxikologie GmbH, Flörsheim, Germany. From this culture the neotype of E. albidus has been selected (Erséus et al. 2019). In this way our morphological characters substantially agree with those described in Erséus et al. (2019). MEASUREMENTS. Segment number 58–65, body length 15.5–20.8 mm, 850–900 μm wide at clitellum in vivo (700–980 μm, when fixed). CHAETAE. In ventral bundles mostly 3–5 (Fig. 6A). BRAIN. 125–165 μm long, 1.2–1.8 × as long as wide (fixed). PHARYNGEAL GLANDS. Variable, all converging or connected dorsally, or not converging (in Erséus et al. 2019: all converging). COELOMOCYTES. 17–32 μm long, mostly oval or spindle-shaped, granulated (in Erséus et al. 2019: 10– 20 μm). In the coelomocytes mostly shining, hyaline, round or tetragonal corpuscles (diameter 9–15 μm) are also present, similar to E. adrianensis sp. nov. CLITELLUM. Hyalocytes and granulocytes of clitellum irregularly arranged dorsally (Fig. 6B). Ventral surface of XII with a recess between lip-like folds (Fig. 6C–D, J). NEPHRIDIA. Four pairs of nephridia preclitellarly (Fig. 6G). SPERM FUNNELS. 700–820 μm long in vivo, 5–6 × as long as wide, the collar as wide as funnel body (Fig. 6H). Head of spermatozoa 30–60 μm long. Sperm duct ciliated (Fig. 6E–F), elongate, about the same width throughout (30–44 μm wide, with 9–16 μm thick wall), coiled, extending into XIV–XVII. MALE COPULATORY ORGANS. Male glands multiple: one larger rounded primary bulb (65–80 μm, fixed) and numerous smaller glands (40–50 μm, fixed) (Fig. 6I). SPERMATHECAE. Ectal duct of spermatheca 105–200 μm long, diameter of glands around duct 90–130 μm in vivo. Diverticulum of ampulla 180–237 μm long and 70–125 μm wide in vivo (Figs 1F, 6K–L). For similarities and differences of the species of Enchytraeus studied by us, see Table 2. Distribution and habitat Laboratory culture. For additional references, including synonymies and further distributional data, see Erséus et al. (2019)., Published as part of Nagy, Hajnalka, Dózsa-Farkas, Klára & Felföldi, Tamás, 2023, New insights into the Enchytraeus albidus complex (Annelida, Enchytraeidae), with the description of three new species from seashores in Italy and Croatia, pp. 107-145 in European Journal of Taxonomy 870 on pages 22-24, DOI: 10.5852/ejt.2023.870.2123, http://zenodo.org/record/7986633, {"references":["Henle F. G. J. 1837. Ueber Enchytraeus, eine neue Anneliden-Gattung. Archiv fur Anatomie, Physiologie und Wissenschaftliche Medicin 74 - 90.","Erseus C., Klinth M. J., Rota E., Wit P. D., Gustafsson D. R. & Martinsson S. 2019. The popular model annelid Enchytraeus albidus is only one species in a complex of seashore white worms (Clitellata, Enchytraeidae). Organisms Diversity & Evolution 19: 105 - 133. https: // doi. org / 10.1007 / s 13127 - 019 - 00402 - 6"]}

Enchytraeus krumbachi (Čejka, 1913) Figs 1B, 7–8, Tables 1–2 Enchytraeus krumbachi Cejka, 1913: 145–151, figs 1–10. Enchytraeus krumbachi – Erséus et al. 2019: 126–129, fig. 12. Emended diagnosis As a result of our comparisons, we suggest the following diagnosis of the species: (1) Body length 15–25 mm (in vivo), segment number 40–66; (2) chaetae maximum 4 (5, 6) per bundle; (3) granulocytes and hyalocytes irregularly arranged dorsally in clitellum; (4) four pairs of nephridia preclitellarly; (5) the pharyngeal glands are connected dorsally; (6) dorsal blood vessel origin from XV, blood colourless; (7) sperm funnel 1.2–3 × as long as wide (fixed); (8) vasa deferentia tripartite, extending into XIV–XIX, the middle part thicker, unciliated, the thinner part ciliated; (9) male copulatory organs: one large rounded primary bulb, slightly longer than wide (80–100 μm × 70–90 μm), many smaller secondary glands; (10) ampulla of spermatheca rounded, large, without diverticula, ectal duct with large glands covered; (11) 4–10 mature eggs present at a time. For similarities and differences of the species of Enchytraeus studied by us, see Table 2. Material examined ITALY • 11 specs (+ 12 specs only in vivo); Castiglione seashore; ID 1383, 1385, slide 2867 to 2869, 2872, 3004, 3006 to 3007, 3014 to 3015; ELTE • 3 specs; Punta Ala Grosseto; slide 3174, 3180 to 3181; ELTE. Description of new material and comparison with previous accounts Morphological characters identical with the description by Čejka (1913) and Erséus et al. (2019). Unfortunately, we did not have the opportunity to study the type material, but the original description is quite detailed and can be compared with our own data. MEASUREMENTS. Segment number 40–66. In vivo, body length 15–25 mm, width at clitellum 700– 950 μm; when fixed, length 7–14 mm (with first 12 segments 2.7–3.8 mm), width 500–860 μm. Čejka (1913) originally reported 66–75 segments, and body ca 15 mm long, and Erséus et al. (2019), studying fixed worms, noted length of 2.9–3.8 mm for first 12 segments, and width of 400–620 um at clitellum. Thus, our specimens are roughly identical in general size to earlier studied material, although slightly wider than individuals examined by Erséus et al. (2019). CHAETAE. Chaetal formula: 2,3–2,3:2,3,4,(5,6)–2,3. In ventral preclitellar bundles of some specimens 3 chaetae, and only one or two bundles with 4 chaetae, in other specimens 4 chaetae in all or most bundles; sometimes 2–3 surplus chaetae can be found. In Erséus et al. (2019), chaetal formula 3–2:3,4–2 and there are always 2 chaetae per bundle postclitellarly. Some of our individuals with 3 chaetae per bundle postclitellarly. In one specimen, 5 and 6 chaetae occured in some preclitellar ventral bundle. Čejka mentioned 3 chaetae in lateral and 4 chaetae in ventral bundles. Size of chaetae similar to size given by Erséus et al. (2019) (Table 2). 2–3 surplus chaetae also occasionally occur (Fig. 7A). COELOMOCYTES. Round or narrowed at one end, texture granulated, 15–27 μm length in vivo (Fig. 7B), (fixed not well measurable) Erséus et al. (2019): 10–15 μm, fixed. Shining, hyaline corpuscles mostly absent, but in some specimens occuring in few numbers. CLITELLUM. Granulocytes and hyalocytes irregularly arranged dorsally (Fig. 7C). In Erséus et al. (2019), ventral surface of XII with invaginations creating two recesses with overhanging lips. In our specimens near to male copulatory glands laterally (Fig. 7D) and ventrally between lips and midventrally only granulocytes (Fig. 7E). Čejka (1913) does not give any description of epidermal gland cells of epidermis. PHARYNGEAL GLANDS. In Erséus et al. (2019), pharyngeal glands are connected dorsally, in our individuals the position is mostly the same (Fig. 7F), but sometimes the first and second pairs of primary pharyngeal glands did not connect or they just contacted (Fig. 7G). In an unusual way, the third pair of pharyngeal glands was completely absent in one specimen. NEPHRIDIA. Four pairs of preclitellar nephridia at 6/ 7–9 / 10. SPERM FUNNELS. Length: width ratio of sperm funnel (Fig. 7I) 1.2–3:1 (fixed), (Erséus et al. 2019: 1.5–2:1, Čejka 1913: 3:1). Vas deferens (Fig. 8A–B) has same structure, tripartite, middle part thicker (55–75 μm with 20–30 μm wall thickness), unciliated, thinner ductus 20–37 μm thick and ciliated. Sizes of thicker part of ductus slightly larger than given by Erséus et al. (2019) (50–55 μm, with 15 or 15–30 μm wall thickness). In Erséus et al. (2019), vas deferens reaches XVIII, in our specimens variable: XIV–XIX, in Čejka (1913), it reaches XVI. SPERM SACS. Well developed, paired sperm sacs (Figs 7H, 8C) in IX–XI. MALE COPULATORY ORGANS. One large rounded primary bulb, slightly longer than wide (80–100 μm × 70– 90 μm), according to Erséus et al. (2019): diameter 85–90 μm and many smaller secondary (accessory) glands (Fig. 8D–E). In Čejka (1913), 6 gland complexes around penial bulb. SPERMATHECAE (Figs 1B, 7F–G, 8F–H). Without diverticula, ampulla round, large [70–140 μm, in Erséus et al. (2019): 95–125 μm], ectal duct with large glands covered (Figs 1B, 8F–H). In Erséus et al. (2019), ectal duct of spermatheca entally opening into small rounded chamber but we did not observe this chamber, and it is not mentioned in Čejka’s original description. Besides, differences in length and diameter of ectal duct (see Table 2). According to the morphological comparisons above, we think that our specimens agree better with the morphological description of Čejka (1913). Distribution and habitat Castiglione seashore, Ligurian Sea, Italy, decaying seagrass debris. Punta Ala Grosseto, Castiglione della Pescaia, Italy, decaying seagrass debris., Published as part of Nagy, Hajnalka, Dózsa-Farkas, Klára & Felföldi, Tamás, 2023, New insights into the Enchytraeus albidus complex (Annelida, Enchytraeidae), with the description of three new species from seashores in Italy and Croatia, pp. 107-145 in European Journal of Taxonomy 870 on pages 24-27, DOI: 10.5852/ejt.2023.870.2123, http://zenodo.org/record/7986633, {"references":["Cejka B. 1913. Litorea krumbachi n. spec. n. gen. Ein Beitrag zur Systematik der Enchytraeiden. Zoologischer Anzeiger 17: 145 - 151.","Erseus C., Klinth M. J., Rota E., Wit P. D., Gustafsson D. R. & Martinsson S. 2019. The popular model annelid Enchytraeus albidus is only one species in a complex of seashore white worms (Clitellata, Enchytraeidae). Organisms Diversity & Evolution 19: 105 - 133. https: // doi. org / 10.1007 / s 13127 - 019 - 00402 - 6"]}

Mesenchytraeus globiferus sp. n. (Figures 2E, 10–12) Type material. Holotype: NIBRIV0000886170, slide No. 3111a+b+c, adult, stained specimen. Type locality: Jeoksangsan, Jeoksang-myeon, Muju-gun, Jeollabuk-do, Korea, soil and litter layers of Quercus serrata and mixed forests, N 35˚56′55.02″, E 127˚40′41.99″, 476 m asl, 06.11.2019. Paratypes: NIBRIV0000886171, slide No. 2910a+b (last 38 segments, 5.9 mm, for DNA analysis No. 1423) and NIBRIV0000886172, slide No. 2967, adult, stained, mounted specimens, from type locality. P.138.1–P.138.12., slide No. 2879, 2901a,b, 2945a,b, 2968a,b, 3105a-d, 3107a,b, 3109a,b, 3110a,b, 3112a,b, 3113a.b, 3114a-c, adult, stained specimen, whole mounted. P.138.13., 5 adult and 2 juvenile specimens in 70% ethanol. Further material examined. 3 specimens, ruined after preservation Etymology. The species is named after the characteristic globular everted bursae [globiferus = globe-bearing (Latin)]. Diagnosis. The new species can be recognized by the following combination of characters: (1) large worms (27.5–37 mm long and about 1 mm at clitellum in vivo, 13–21.6 mm long when fixed), 70–94 segments, colour yellowish, dark brown pigment in head region; (2) chaetae sigmoid with nodulus, maximum 4–5 per bundle, in V– VII ventrally only 2–3 slightly enlarged chaetae, the size from V–XI ventrally about the same. Postclitellarly more chaetae in one bundle, maximum number may be 6 (7–8) ventrally and 4–5 (6) laterally; (3) clitellum girdle-shaped; (4) five preclitellar pairs of nephridia; (5) dorsal blood vessel from XXII–XXVIII, blood light pink; (6) two pairs of primary and 4 pairs of secondary pharyngeal glands, lobed, not connected dorsally; (7) sperm funnel 670–880 µm long and 4–8 times longer than wide in vivo, sperm ductus loosely coiled in XII–XIII, diameter 30–40 µm, fixed. Atrium 300–550 µm long, maximum width 120–160 µm (fixed) with 6–7 large atrial glands; (8) the bursa mostly everted as a large ball (diameter 500–950 µm, fixed). The atrium lies in the bursa and some large multicellular penial glands fill the cavity of the bursa; (9) the part of the sperm duct after the atrium is very long and protrudes far from the bursa (true penis); (10) sperm sacs and egg sac may extend into XXIII–XXIV; (11) spermathecal ampullae proximally fused and attached to the oesophagus in V. The ectal ducts different lengths (320–550 µm long and 60 µm wide, fixed). Ectally with a large ectal gland, surrounded by a large cavity, the aperture is large. Description. Large enchytraeid worm. Colour yellowish, prostomium dark-brown by pigmentation (Fig. 10A); dorsal side of first few segments light brown mottled (Fig. 10B). Holotype 17.6 mm long, 920 µm wide at VIII and 1600 µm at clitellum (fixed), segment number 90. Body lengths of paratypes 27.5–37 mm, width 780–1000 µm at VIII and 825–1300 µm at clitellum in vivo; lengths of fixed specimens 13–21.6 mm, width 640–930 µm at VIII and 700–1050 µm at clitellum. Segments (62)–70–94. Strong external segmentation at body end. Chaetae sigmoid with nodulus. Chaetal formula: 2,3–3, (2),4,5,(6): 4,5,3,2– 3,4,5,6, (7,8),3,2. Chaetae mostly unequal in size within a bundle: in ventral bundles a gradual increase in length towards the ventral midline and in lateral bundles an increase in length in dorsal direction, as usual in most Mesenchytraeus species. In II–IV mostly 3–5 chaetae per bundle ventrally (Fig. 10B) (about 90–145 × 8 µm). In V–XI only 2–3 larger and stronger chaetae (140–190 × 12 µm), in X–XI the length of the chaetae slightly smaller (150–170 × 12 µm) (Fig. 10C). Behind clitellum, chaetae slightly smaller and thinner (135–150 × 10 µm). Chaetae of lateral bundles slightly smaller and thinner than ventrals. At the body end, longest chaetae measuring 120–160 × 8-9 µm (Fig. 10D). Chaetae in XII absent. Head pore at 0/I, a large transverse slit (Fig. 10A). Clitellum girdle–shaped in XII–XIII, gland cells small, in reticulate pattern. Thickness of body wall about 120–140 µm, cuticle Brain (Fig. 10H) incised anteriorly and slightly convex posteriorly, wider than long (e.g. 125 µm long and 165 µm wide, fixed). Two pairs of primary pharyngeal glands (in 4/5–5/6), not united dorsally, and four (in one case five pairs) of secondary pharyngeal glands in V –VIII (IX); the glands lobed (Fig. 10I). Yellow-brownish chloragocytes from IV, about 30–45 µm long, fixed. Dorsal blood vessel from XXII–XXVIII, anterior bifurcation in I, blood light pink. Five pairs of preclitellar nephridia from 6/7 to 10/11, anteseptale funnel only, postseptale lobed with folded canal, no interstitial tissue, efferent duct arising between the lobes (Fig. 10J). Oesophageal and intestinal appendages or diverticula absent. Coelomocytes were not observable. Sperm sac extending backwards to XXIII–XXIV, egg sac to XIV –XXV. In one specimen the sperm bundles were measurable, 230 µm long, the heads clumped only at one end and 50 µm long (Fig. 10M). Sperm funnel (Figs 10K–L) about 670–880 µm long and 4–8 times longer than wide in vivo (425–970 µm long, and 3–5.5 times longer than wide, when fixed). Sperm duct long, loosely coiled in XII–XIII, diameter 30–40 µm, fixed. Atrium (Fig. 8D) 300–550 µm long, maximum width 120–160 µm, here joined by 6-7 large atrial glands (prostate glands), usually 230 – 300 µm long (Figs 11A, C). Among enchytraeids, the male copulatory organ shows the most complex structure in the genus Mesenchytraeus (Eisen 1904). In this species the eversible pouch (= bursa after Schmelz 2003) mostly appears as a huge projected ball (Figs 11A–D), diameter about 500–950 µm, in fixed specimens. Atrium and atrial glands lie inside this projection (i.e., the everted bursa), the atrial glands only partially. Near the atrium there are large multicellular ‘penial’ glands (perhaps 3–4, number difficult to determine) which fill the cavity of the bursa (Fig. 11D). A special feature is that the most distal part of the sperm duct after the atrium is very long and protrudes far outside the bursa (400–620 µm long and 50–110 µm wide, fixed) (Fig. 11C,E). The everted bursa was formerly called penis, but according to its usual structure it is not able to deliver sperm directly to the spermatheca, so it is not a penetratory organ but serves as clasper, and most of the secretions of the adjoining glands are probably adhesive slimes (Schmelz 2003), as we can see, e.g., in Mesenchytraeus calyx (Dózsa-Farkas et al. 2015, p.188, Fig. 11A). However we believe that in this species the male copulatory organ actually functions as a penis, because the diameter of the spermathecal opening (about 220 µm long) (Figs 12C–D) is approximately equal to the diameter of the protruding long sperm duct, named here as penis (width 70–90 µm on average, maximum width 110 µm, narrower at apex). Subneural glands absent. The spermathecae (Figs 2, 12E–I) were difficult to see due to highly stained pharyngeal glands, and were therefore partially removed from dissected individuals. Ectal ducts of different length in the same animal, one side mostly shorter, 320–450 µm; length 436–550 µm on the other side, width 40–60 µm, fixed. Ectally it opens into a spacious “capsule” containing a large gland (Fig. 11F,G). This, as mentioned above, opens with a wide aperture to the outside (Fig. 12C,D). The ectal duct projects deeply into the ampulla, which has two elongate diverticula projecting backwards and lining ectal duct on opposite sides. The proximal parts of the two ampullae are fused and attached to the oesophagus in V, and probably also connected with it (the connection was not observable). Distribution and habitat. Only known from type locality (Site 1): Jeoksangsan, Jeoksang-myeon, Muju-gun, Jeollabuk-do, Korea, soil and litter layers of Quercus serrata and mixed forests, N 35˚56′55.02″, E 127˚40′41.99″, 476 m asl. Differential diagnosis. The Mesenchytraeus globiferus sp. n. differs from all known Mesenchytraeus species in the form of the spermatheca (large ectal gland, surrounded by a large cavity, and the fusion of the two ampullae) and by the large spherical eversible bursa with elongate, from the bursa protruding sperm duct, the bursa. The morphological separation was supported also with the molecular results.

Henlea bidiverticulata sp. n. (Figures 2C, 5 – 6) Type material. Holotype: NIBRIV0000860933, slide No. 2505, adult, stained, whole mounted specimen. Type locality: Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Korea, soil of Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl, 31.10.2017. Paratypes (in total, 19 specimens): NIBRIV0000860934, slide No. 2510, NIBRIV0000860943, slide No. 2511, P.132.1–14, slide No. 2493–2498, 2506, 2508–2509, 2523 (DNA ID: 1201), 2554–2555, 2565, 2567, P.132.15–P.132.17, slide No. 2814–2816, adult, stained whole mounted specimens from the type locality. Further material examined. Two specimens only in vivo from Mt. Gyebangsan, Nodong-ri, Yongpyeongmyeon, Pyeongchang-gun, Gangwon-do, Korea, soil and litter layers of Q. mongolica forest, N 37°42’24.78”, E 128°29’09.95”, 804 m asl, 31.10.2017. Etymology. Named after the paired intestinal diverticula. Diagnosis. The new species can be recognized by the following combination of characters: (1) mobile worms, about 7–10 mm long and 280–410 μm wide at clitellum in vivo, segments 34–46; (2) maximum 6–7–(8) chaetae per bundle; (3) clitellum girdle-shaped: hyaline and granular gland cells in indefinite rows dorsally, but between the bursal slits only granulocytes; (4) five preclitellar pairs of nephridia; (5) two lateral intestinal diverticula in VIII, dorsal vessel origin in IX; (6) coelomocytes oval with fine granules; (7) seminal vesicle absent; (8) sperm funnel small, cylindrical, collar as wide as or slightly narrower than funnel body; (9) spermatheca simple, ampulla slightly wider than the ectal duct, ental ducts unite before joining the oesophagus dorsally. Description. Very motile worms, mostly covered with soil particles and organic debris. Holotype 4.35 mm long, 270 μm wide at VIII and 270 μm at clitellum, fixed, 44 segments. Body length of paratypes (5.6), 7–10 mm, width 210–370 μm at VIII and 280–410 μm at clitellum in vivo. Length of fixed specimens 3.5–4.9 mm, width 260–380 μm at VIII and 260–420 μm at clitellum. Segments 34–46. Chaetal formula: 3,4,5,(6)–4,5,6: 4,5,6,(7,8)–4,5,6,7(8). Chaetae straight, mostly equal in size within a bundle, 35–46 μm long preclitellarly and 38–50 posteriorly, and 3 μm wide. Chaetae in XII absent. Head pore at 0/I, transverse slit (Fig. 5C). Epidermal gland cells arranged in 4–5 transverse rows per segment (Fig. 5D). Many glands also on the prostomium dorsally (Fig. 5C). Clitellum girdle-shaped in XII–1/2XIII, larger hyaline and smaller granular gland cells in indefinite rows dorsally (Fig. 5E, F); between the bursal slits only granulocytes (Figs 5 G–I). Thickness of body wall about 20–34 μm, cuticle in vivo. Brain incised posteriorly, about 100–150 μm long, in vivo (90–125 μm, fixed) and 1.2–1.9 times longer than wide (Figs 5 A–B). Two pairs (?) of inconspicuous oesophageal appendages in VI, canal in V–IV absent. Mostly all pharyngeal glands free dorsally but close to each other. Sometimes first and third pairs united dorsally, the second pair free (Fig. 6J) or only the third pair united (Fig. 6I), second and third pair with ventral lobes. Chloragocytes from IV about 17–23 μm long (fixed). Dorsal vessel from IX, with heart-like expansions in IX–VII (Figs 2C, 5P), blood colourless, anterior bifurcation in peristomium. Intestinal diverticula a pair of lateral bodies in VIII, rounded or apparently tapering towards free end (Figs 2C, 5 L–M), but laterally visible as flat rounded lobes (Fig. 5N). Inside the diverticula exists a small cavity and some canals (Figs 5L, P). Pars tumida of midgut exhibits a mixture of hyaline and granular epithelium cell-types around the gut wall circumfence, similar to H. glandulifera (type 1, after Rota et al. 1998), in XXII–XXIX, occupying 5–6 segments length (Fig. 6B). Five pairs of preclitellar nephridia, from 6/7 to 10/11, anteseptale small, efferent duct originates anteroventrally (Fig. 5K). Coelomocytes only mucocytes, ellipsoid (Fig. 5J), with fine granula, not brown in transmitted light (length 22–32 μm in vivo, 22–28 μm when fixed). Seminal vesicle absent. Sperm funnel small, cylindrical (Figs 6C, D), about 70–100 μm long and 1.2–2.2 times as long as wide in vivo. Funnel length in fixed specimens 53–76 μm, 1–1.5 times longer than wide. Collar about as wide as funnel body. Spermatozoa about 77–80 μm long, heads 21–26 μm in vivo (30–50 μm and 12–13 μm, fixed), diameter of sperm ducts 6–8 μm in vivo. Penial bulbs (Figs 6E, F) large, compact, about 97–120 μm long, 55–95 μm wide and 50–70 μm high in vivo (65–90 μm long, 55–75 μm wide and 50–70 μm high when fixed). Subneural glands absent. Spermathecae (Figs 2C, 6H, J) simple, without diverticula, ampullae may not be distinctly set off from ectal ducts (diameter of ectal duct about 15–19 μm), ental ducts merging entally and with joint opening into oesophagus in VI dorsally. At the ectal orifice of spermathecal ducts 2–3 variably large glands (20–50 μm long, in vivo) (Figs 6 G–H). 1–3 mature eggs at a time. Distribution and habitat. In Korea: Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl; Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers, N 37°42’24.78”, E 128°29’09.95”, 804 m asl. Differential diagnosis. Henlea bidiverticulata sp. n. and six other Henlea species are characterized by one pair of free-projecting lateral intestinal diverticula in VIII. Among them, three species found in North America (H. glabra Altman, 1936, H. urbanensis Welch, 1914, H. eiseni Bell, 1942) are much larger (66–71, 65–66 and 50–53 segments, respectively, vs. 34–46 segments in the new species). H. nasuta (Eisen, 1878) is also much larger (15–25 mm long in vivo, vs. 5.5–10 mm in H. bidiverticulata), moreover it has larger intestinal diverticula, the origin of the dorsal vessel lies between the diverticula in VIII (Fig. 8A), and the coelomocytes are rounded, dark brown (Figs 8B, C). The ampulla of spermatheca is conspicuous in H. nasuta, but narrower in H. bidiverticulata sp. n. (Fig. 8C, vs. Fig. 6H). In H. similis Nielsen & Christensen, 1959, the ampulla of the spermatheca is more similar to the new species (Fig. 8D) but the intestinal diverticula occupy also posteriorly parts of IX (Fig. 8E), whereas in the new species this organ originates at 8/9 and is confined to VIII (Figs 5 L–P). In many traits H. bidiverticulata sp. n. is most similar to H. glandulifera Nurminen, 1970, e.g., size and the number of segments [8–12 mm, 36–50 segments in vivo in H. glandulifera (vs. 7–10 mm, 34–46 segments)], the arrangement of the clitellar glands (Figs 7A, B vs. Figs 5 E–I), epidermal glands (Fig. 7C vs. Fig. 5D), the form and size of intestinal diverticula (Fig. 7 D–F vs. Figs 5 L–P, 6A)], but differs from it and from the other two species mentioned above by the origin of dorsal vessel in IX (Figs 5M, P. Moreover, the new species has only 5 pairs of preclitellar nephridia [vs. six pairs in H. glandulifera (Rota et al. 1998)]. The sperm funnel is also smaller: 70–100 μm long in vivo (53–76 μm, fixed), but in H. glandulifera 95–140 μm in vivo (et al. (1998) in vivo and 136–177 μm when fixed]. Spermatozoa are also smaller: length 72–80 μm, heads 21–26 μm in the new species, while 95–150 μm and 35–60 μm in H. glandulifera after own observations, and 105 μm and 27 μm after Rota et al. (1998) in vivo. Besides, in H. glandulifera there are two conspicuous winding channels above the oesophagus in V from the oesophageal appendages (Fig. 7J), which are absent in the new species. The molecular taxonomic results also support the description of the new Henlea species (see below).

Henlea nasuta (Eisen, 1878) sensu Nielsen & Christensen, 1959 (Figure 17) Material examined. 25 specimens (three specimens were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000837806 and NIBRIV0000866135, in 70 % ethanol). Our observations agree with the diagnostic features reported by Nielsen & Christensen (1959), Rota et al. (2018) and others assembled by Schmelz & Collado (2010). Large worms, 15–25 mm long and about 1 mm wide. Segments 48–50. Clitellum girdle-shaped, gland cells in reticulate pattern (Figs 17E, F), penial bulb small (Fig. 17F). Chaetae maximum 7–8 per bundle. Oesophageal appendages spongy, with paired dorsal and ventral lobes in VI, winding canals from VI to IV (Fig. 17D), and in IV a free plurilobed projection middorsally and midventrally (Fig. 17C). Intestinal diverticula two large rounded pouches attached laterally in VIII (Fig. 17A). Dorsal vessel arising in VIII, between intestinal diverticula (Fig. 17A). Five pairs of preclitellar nephridia. Coelomocytes discoid, opaque, with fine brownish granules (Fig. 17B). Sperm funnels about twice as long as wide (Fig. 17G). Spermathecae with pear-shaped ampullae. Ectal ducts long without glands. Ental ducts united before attaching to the oesophagus (Fig. 17H). Distribution and habitat in Korea. Mt. Deogyu, Seolcheon-myon, Muju-gun, Jeollabuk-do, soil and litter layers, Q. mongolica forest, N 35°51’31.6”, E 127°46’11.3”, 898 m asl; Mt. Gyebangsan, Nodong-ri, Yongpyeongmyeon, Pyeongchang-gun, Gangwon-do, Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl; Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers, Q. mongolica forest, N 37°42’24.78”, E 128°29’09.95”, 804 m asl; Mt. Gwaebangsan, near to Deungmyeongnakgasa temple of Mt. Gwaebangsan, Gangdong-myeon, Gangneung-si, Gangwon-do, soil and litter layers of Q. mongolica forest, N 37°42’31.76”, E 129°00’17.54”, 144 m asl.

Marionina clavata Nielsen & Christensen, 1961 (Figure 18) Material examined. 5 specimens (three were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000866133, NIBRIV0000866134, NIBRIV0000837805, in 70 % ethanol). Our observations mostly agree with the description of Nielsen & Christensen (1961). Small worms (4–7 mm long, 280–330 μm wide at XII in vivo), segments 22–27. Chaetae straight, maximum 2 per bundle, absent laterally in VIII–XII (but in the original description in IX–XII). Clitellum saddle-shaped, gland cells pattern irregular (Fig. 18A), glands absent midventrally (Fig. 18B). Brain incised posteriorly. A pair of short, club-shaped, hollow oesophageal appendages present dorso-laterally in IV (Figs 18 C–E). All pharyngeal glands connected dorsally (Fig. 18C). Dorsal blood vessel origin in XII, anterior bifurcation in I. Coelomocytes oval, 25–28 μm long, finely granulated. Two pairs of preclitellar nephridia at 7/8–8/9, with considerable anteseptale, postseptale with gradual transition into terminal efferent duct (Fig. 18F). Sperm funnels (Fig. 18G) and penial bulbs small (Fig. 18B). Spermathecae possess long ental ducts covered with small glands all along. Ampullae pear-shaped, ental ducts united dorsally and communicating with oesophagus (Figs 18H, I). Distribution and habitat in Korea. Mt. Odaesan, Sangwonsa, Dongsan-ri, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers, Abies holophylla forest, N 37°47’09.03”, E 128°33’42.75”, 969 m asl; Mt. Jumbong, near to Hangyeryong, Inje-gun, Gangwon-do, soil and litter layers of Q. mongolica forest, N 38°05’17.33”, E 128°23’12.49”, 659 m asl.

Fridericia cf. sohlenii Rota, Healy & Erséus, 1998 (Figure 16) Material examined. Five specimens (three were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000860938, in 70 % ethanol). Our observations substantially agree with the description of Rota, Healy & Erséus (1998), except for a few traits (see details in discussion). Middle-large worms, 10–14 mm long, 390–430 μm wide at clitellum in vivo, segments 40–49 (in the original description the number of segments is slightly higher: 45–56). Body covered with debris and soil particles. Chaetae 2 in all bundles, several parcels of detached chaetae in the coelom (Fig. 16F). Clitellum girdle-shaped, gland cells form an irregular pattern (Figs 16B, C), between the penial bulbs mostly granular cells, but some hyaline cells can occur (Fig. 16D). Brain about twice as long as wide (Fig. 16A). Oesophageal appendages a-type. Dorsal blood vessel from XV–XVI, chylus cells in X–XI, occupying 2 segments. Mucocytes 27–36 μm long with refractile granules at periphery (b-type) (Figs 16 F–G). Lenticytes large, 9–12 μm long. Five pairs of preclitellar nephridia at 6/7–10/11. Seminal vesicle absent. Sperm funnels cylindrical, 135–157 μm long, 1.8–3 times longer than wide in vivo (Fig. 16H), uniformly granular. Penial bulbs about 160 μm long and 90 μm wide in vivo (Fig. 16D). Bursal slit not T-shaped as in the original description, but longitudinal. Spermathecal ampulla carrying two rounded sessile diverticula. Ectal duct long, about 190–250 μm long and 15 μm wide, with one or two ectal glands at orifice. Diverticula mostly empty; sperm, when present, not rotating (Figs 16I, J). Distribution and habitat in Korea. Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Quercus mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl; Mt. Odaesan, Sangwonsa, Dongsan-ri, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, Korea, soil and litter layers, mixed forest, N 37°47’03.63”, E 128°33’44.06”, 906 m asl., Published as part of Felföldi, Tamás, Dózsa-Farkas, Klára, Nagy, Hajnalka & Hong, Yong, 2020, Three new enchytraeid species (Enchytraeidae, Annelida) from mountain soils of Korea and ten species new for the country, pp. 1-45 in Zootaxa 4896 (1) on pages 30-31, DOI: 10.11646/zootaxa.4896.1.1, http://zenodo.org/record/4358984, {"references":["Rota, E., Healy, B. & Erseus, C. (1998) Biogeography and taxonomy of terrestrial Enchytraeidae (Oligochaeta) in Northern Sweden, with comparative remarks on the genus Henlea. Zoologischer Anzeiger, 237, 155 - 169."]}

Cognettia lapponica Nurminen, 1965 (Figure 14) Material examined. 14 specimens (one was deposited in the National Institute of Biological Resources, Korea; NIBRIV0000837799, slide No. 2542). Small worms (6–10 mm long and 230–380 μm wide at XII in vivo), segments 31–36. Chaetae maximum 3 per bundle, sigmoid without nodulus (Fig. 14C). Clitellum saddle-shaped, gland cells pattern irregular dorsally (Fig. 14B), glands absent ventrally (Fig. 14C). Brain slightly incised posteriorly (Fig. 14A). Three pairs of nephridia preclitellarly 6/7–8/9 (Fig. 14D). In the literature, the position of preclitellar nephridia was unknown (Nurminen 1965, Schmelz & Collado 2010), but the number of nephridia in Korean specimens differs from those which were collected from Siberia and Alaska, which have 4 pairs of preclitellar nephridia (6/7–9/10) (observation of K. Dózsa- Farkas, unpublished). Three pairs of dorsal pharyngeal lobes free, all without ventral lobes (Fig. 14D), and 2 pairs of secondary ventral lobes in V, VI (Fig. 14D). Dorsal blood vessel origin in XIV, blood colourless. Sperm funnels 120–180 μm long in vivo, mostly 2.5–3.5 times longer than wide, collar as wide as funnel body (Fig. 14F). Spermatozoa 60–78 μm long, heads 25–30 μm. Male pores in normal position in XII, with well-developed glandular bulbs (Fig. 14E). Spermathecae (Figs 14 G–I) confined to V with long ectal ducts and with small ectal glands. Ducts widen into ampullae. Ampulla followed by duct connecting to spherical ental chamber. Spermathecae not connected to oesophagus. One or two mature eggs at a time. Distribution and habitat in Korea. Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl; Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers of Q. mongolica forest, N 37°42’24.78”, E 128°29’09.95”, 804 m asl., Published as part of Felföldi, Tamás, Dózsa-Farkas, Klára, Nagy, Hajnalka & Hong, Yong, 2020, Three new enchytraeid species (Enchytraeidae, Annelida) from mountain soils of Korea and ten species new for the country, pp. 1-45 in Zootaxa 4896 (1) on page 28, DOI: 10.11646/zootaxa.4896.1.1, http://zenodo.org/record/4358984, {"references":["Nurminen, M. (1965) Enchytraeids (Oligochaeta) from northern Norway and western Lappland. Annales Zoologici Fennici, 2, 11 - 15.","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82 (1), 1 - 176."]}

Mesenchytraeus longidiverticulatus sp. n. (Figures 2D – F, 9, 10) Type material. Holotype: NIBRIV0000860935, slide No. 2593, adult, stained specimen. Type locality: Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Korea, Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl, 31.10.2017. Paratypes (in total, 11 stained, adult specimens on slides): NIBRIV0000860936, slide No. 2608, one adult, stained specimen, locality: Mt. Chiaksan, Hakgok-ri, Socho-myeon, Wonju-si, Gangwon-do, Korea, soil and litter layers of mixed forests, N 37°22’58.07”, E 128°03’30.83”, 484 m asl, 02.11.2017. NIBRIV0000860944, slide No. 2791, Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Korea, soil and litter layers of Q. mongolica forest, N 37°42’24.78”, E 128°29’09.95”, 804 m asl, 31.10.2017. P.133.1–P.133.4, slide No. 2594–2596, 2620, from type locality. P.134.1–P.134.2, slide No. 2591, 2614, locality: Mt. Chiaksan, Hakgok-ri, Socho-myeon, Wonju-si, Gangwon-do, Korea, soil and litter layers of mixed forests, N 37°22’58.07”, E 128°03’30.83”, 484 m asl, 02.11.2017. P. 134.3, slide No. 2613, locality: Mt. Chiaksan, Hakgok-ri, Socho-myeon, Wonju-si, Gangwon-do, Korea, soil of mixed forests and Quercus serrata forest, N 37°23’36.50”, E 128°03’15.30”, 395 m asl, 02.11.2017. P. 135, slide No. 2530, locality: Mt. Odaesan, Sangwonsa, Dongsan-ri, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, Korea, soil and litter layers of mixed forest, N 37°47’03.63”, E 128°33’44.06”, 906 m asl, 01.11.2017. P. 136, slide No. 2894 (last 14 segments, 1.4 mm, for DNA analysis: ID 1416), locality: Mt. Gongjaksan, Gurun-ri, Hwachon-myeon, Hongcheon-gun, Gangwon-do, Korea, soil and litter layers of Q. mongolica and mixed forests, N 37°42’15.71”, E 128°00’43.41”, 403 m asl, 25.10.2019. Further material examined. Five subadults from type localiy, from Mt. Chiaksan and Mt. Gwaebangsan, Gangdong-myeon, Gangneung-si, Gangwon-do, Korea, soil and litter layers of Q. mongolica forests, near to Deungmyeongnakgasa temple of Mt. Gwaebangsan, N 37°42’31.76”, E 129°00’17.54”, 144 m asl, 10.11.2018. Etymology. The species is named after the shape of the spermathecal diverticula. Diagnosis. The new species can be recognized by the following combination of characters: (1) middle sized worms (6–13 mm long and about 330–510 µm at clitellum in vivo), segments 40–55, colour whitish; (2) chaetae sigmoid with nodulus, maximum 4–5 per bundle, in V–VII ventrally only 2–3 slightly enlarged chaetae, but the size from VII–XI ventrally about the same or slightly smaller; (3) clitellum girdle-shaped: gland cells in reticulate pattern; (4) five preclitellar pairs of nephridia; (5) dorsal blood vessel from XV–XIX, blood colourless; (6) two pairs of primary and 3–4 pairs of secondary pharyngeal glands, not connected dorsally; (7) small lemon-shaped coelomocytes, light yellow in aggregations in vivo; (8) sperm funnels thick-walled, about 400–580 µm long and 3–7 times longer than wide in vivo, sperm ducts long, reaching as far as XV–XVI; (9) sperm sacs may extend into XV–XVIII, egg sac to XVI–XX; numerous penial glands and some slightly larger accessory copulatory glands extending around male pores; (10) spermatheca attached to the oesophagus in VI–VII, ectal ducts of varying length (150–300 µm long and 30–53 µm wide in vivo), globular ampulla with a very long diverticulum (up to 500 µm long and 30–45 µm wide). Description. Middle-sized enchytraeid worm. Colour whitish. Holotype 7.8 mm long, 360 µm wide at VIII and 390 µm at clitellum (fixed), segment number 49. Body length of paratypes 6–13 mm, width 300–480 µm at VIII and 330–510 µm at clitellum in vivo; length of fixed specimens 3.9–7 mm, width 260–390 µm at VIII and 260–450 µm at clitellum. Segments 40–55. Chaetae sigmoid with nodulus. Chaetal formula: 2,3–2,3: 3,4,3,2,5,(6)–3,4,(5),3,2. Chaetae mostly unequal in size within a bundle: in ventral bundles a gradual increase in length towards the ventral midline and in lateral bundles an increase in length in dorsal direction, as usual in most Mesenchytraeus species (Dózsa-Farkas et al. 2018). In II–IV mostly 3–4 (5) chaetae per bundle ventrally, in V–VI 2–3, in VII–VIII 2–4 (5) chaetae, in IX–XI 3–4, rarely 2 or 5 chaetae. The size of the longest chaetae ventrally gradually increasing from II to VII from 45–50 × 3.5–4 µm to 60–80 µm (maximum 100 µm) × 5–7 µm, the larger and stronger chaetae occur in V and VI. From VII to XI slightly smaller again (50–75 µm by 5 µm) (Fig. 9F). Chaetae of lateral bundles slightly smaller and thinner than ventrals and gradually increasing from II to XI (from 36–47 µm to 50–55 µm by 3–4 µm). At the posterior body end, longest chaetae measuring 60–65 by 5–6 µm. Chaetae in XII absent. Head pore on prostomium, a large transverse slit (Fig. 9E). Clitellum girdle-shaped in XI–XIII or XI–1/2XIV, gland cells in reticulate pattern (Figs 9B, C), between bursal slits less developed (Fig. 9D). Thickness of body wall about 30–45 µm, depending on state of sexual maturity, cuticle about 1 µm. Epidermal gland cells sometimes densely aggregated in segments I-III dorsally (Fig. 9G). Brain (Fig. 9A) incised anteriorly and slightly concave posteriorly, slightly wider than long (80–105 µm long, in vivo). Two pairs of primary pharyngeal glands (in 4/5, 5/6), not united dorsally, and three or four pairs of secondary pharyngeal glands in V–VII (VIII); the secondary glands lobed. Yellow-brownish chloragocytes from IV, about 21–26 µm long in vivo. Dorsal blood vessel from XV–XIX, anterior bifurcation in I (Fig. 9A), blood colourless. Five pairs of preclitellar nephridia from 6/7 to 10/11, anteseptale funnel only, postseptale lobed with folded canal, no interstitial tissue, efferent duct arising between the lobes. Oesophageal and intestinal appendages or diverticula absent. Coelomocytes only mucocytes, lemon-shaped, with granula, in cell aggregations light yellowish in vivo, small, size of cells 22–30 µm (Fig. 9H). Sperm sac extending backwards to XV–XVIII, egg sac to XVI–XX. In sperm sac sperm bundles in rolls (Fig. 10E). Sperm funnel (Figs 9 I–L) thick-walled, about 400–580 µm long and 3–7 times longer than wide in vivo (200–300 µm long, and 3–3.5 times longer than wide, when fixed), mostly reclinate. Sperm duct long, reaching as far as XV–XVI, loosely coiled, diameter 15–21 µm (in vivo); diameter gradually increasing towards atrium. Atrium (Figs 2F, 10 A–D) 250–400 µm long, maximum width 50–65 µm (Fig. 10D), here joined by 4 very large atrial glands (prostate glands), usually 120 – 280 µm long (Figs 10B, D). The atrium connects through an ectal duct (50–120 µm long, in vivo) to the penial bulb, which is surrounded by small penial glands and some accessory glands (about 50 – 100 µm long) (Fig. 10C). Bursal slits large, irregularly transversal, in XII. Subneural glands absent. Spermathecae connected with the oesophagus (Figs 2D, 10 F–J): ectal ducts with variable length, 150–300 µm long and 30–53 µm wide in vivo (60 – 128 µm long and 32–50 µm wide, fixed), devoid of glands. Spermathecal pores in 4/ 5 in lateral position, canal 4–6 µm wide at opening with strong cuticular lining (Fig. 10K). Ampulla globular, diameter about 70–110 µm, with one long diverticulum, whose length reaches 500 µm and width 30–45 µm when filled with sperm, in vivo (130–190 µm long, when fixed). The diverticula can extend posteriorly into VI and/or VII. Sometimes they take a forward direction. Ampulla continuing entally into a flexible elongate ental duct, which ends in VI connected to the oesophagus (Figs 10 F–J). Distribution and habitat. In Korea: Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Korea, Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl; Mt. Gyebangsan, Nodongri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers, N 37°42’24.78”, E 128°29’09.95”, 804 m asl; Mt. Chiaksan, Hakgok-ri, Socho-myeon, Wonju-si, Gangwon-do, soil of mixed forests and Q. serrata forest, N 37°23’36.50”, E 128°03’15.30”, 395 m asl; Mt. Chiaksan, Hakgok-ri, Socho-myeon, Wonju-si, Gangwondo, soil and litter layers of mixed forests, N 37°22’58.07”, E 128°03’30.83”, 484 m asl; Mt. Gwaebangsan, near to Deungmyeongnakgasa temple of Mt. Gwaebangsan, Gangdong-myeon, Gangneung-si, Gangwon-do, soil and litter layers of Q. mongolica forests, N 37°42’31.76”, E 129°00’17.54”, 144 m asl; Mt. Gongjaksan, Gurun-ri, Hwachonmyeon, Hongcheon-gun, Gangwon-do, soil and litter layers of Q. mongolica and mixed forests, N 37°42’15.71”, E 128°00’43.41”, 403 m asl. Differential diagnosis. Up to now, twelve valid species of Mesenchytraeus have been reported with one spermathecal diverticulum. Among these, M. kontrimavichusi Piper, MacLean & Christensen, 1982, M. kuril Healy & Timm, 2000, M. svetae Piper, MacLean & Christensen, 1982 and M. asiaticus Eisen, 1904 have free spermathaecae, not connected to the oesophagus. Among the species with spermathecae attached to the oesophagus and having a single diverticulum, M. armatus (Levinsen, 1884) and M. monodiverticulatus Shen, Chen & Xie, 2012 share with M. longidiverticulatus the enlarged chaetae in some preclitellar bundles ventrally or laterally, but here these chaetae are 1.5–2 times longer and thicker than the others, whereas in the new species their size mostly does not reach 1.5 times the size of the other chaetae. Other differences: M. armatus has more chaetae (maximum of 10–12 vs. 6–7), the diverticulum is elongate but not as long as in the new species, the sperm funnel is pear-shaped (vs. 3–7 times longer then wide) and the enlarged chaetae occur in V–VII segments laterally. In M. monodiverticulatus, the spermathecal diverticulum is ear-shaped and the atrial glands are absent. The remaining six species with one spermathecal diverticulum and entally attached spermathecae are M. celticus Southern, 1909, M. ogloblini Černosvitov, 1928, M. flavus (Levinsen, 1884), M. vivii Timm, 1978, M. torbeni Christensen & Dózsa-Farkas, 1999 and M. laojunensis Chen, Jiang & Xie, 2016. In these species, the spermathecal diverticulum is never as long as the one in the new species and there are no enlarged chaetae. Further observations. An interesting phenomenon should be mentioned: one specimen (paratype slide No. 2620) has three spermathecae (Fig. 2E).

Marionina seminuda Xie & Rota, 2001 (Figure 20) Material examined. 9 specimens (four specimens were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000860939, slide No. 2734, NIBRIV0000860940, slide No. 2735, NIBRIV0000860941, slide No. 2743). Our observations mainly agree with the original description by Xie & Rota (2001), based on Chinese worms, but some dimensional traits were closer to the variation reported by Rota & Manconi (2004) in worms from New Zealand. Small worms (2–3 mm long, 110–145 μm wide at XII in vivo, 1.7–2 mm long and 70–130 μm wide at XII, fixed), segments 17–24. Chaetae straight with distinct ental hook, sharply pointed ectally, present only ventrally from segment III, 2 per bundle (Fig. 20B). 18–30 μm long preclitellarly and longer postclitellarly, 30–40 μm (Fig. 20C) [It differs from the Chinese specimens, where the chaetae of the postclitellar bundles are the smallest. In the specimens from New Zealand (Rota & Manconi, 2004), similarly to the Korean specimens, these are longer postclitellarly, but smaller than in the Korean species (31 μm long (Xie & Rota 2001)]. Clitellar glands large, somewhat squared about in 18–22 transverse rows. Between the male pores glands are absent or 1–2 smaller cells can be found (Fig. 20E). Brain incised posteriorly and convex anteriorly (Fig. 20A) [different from Chinese and New Zealand specimens (vs. concave anteriorly)]. The anterior two pairs of pharyngeal glands merging dorsally, with ventral lobes (small in IV and larger in V), the posterior one in VI elongate and separate (Fig. 20G). Coelomocytes oval, 16–24 μm long with coarse granules, dark in vivo in transmitted light (Fig. 20H) or filled with shining granules when fixed. Dorsal blood vessel from XII or XIII, blood colourless, anterior bifurcation in III (Fig. 20D). Three pairs of nephridia preclitellarly (7/8–9/10). In one specimen, only 2 pairs in 7/8 and 9/10. Sometimes unpaired. Pars tumida of midgut at 1/2 XVII–XIX (occupying 2 segments) (in the Chinese specimens it was found in XVI). Seminal vesicle absent or small. Sperm funnels small, 31–41 μm long, 1.6–2.6 times longer than wide in vivo (31–37 μm long, 1.5– 2.2 times longer than wide, fixed). Collar high and narrower than funnel (Fig. 20I). Sperm ducts irregularly coiled, 4–5 μm wide (in Chinese and New Zealand specimens, regularly coiled). Penial bulbs small, compact, diameter 20–21 μm (Fig. 20E). Spermathecae confined to V, attached to the oesophagus.Ampullae globular 14–17.5 μm wide with spermatozoa in lumen. Ectal ducts 15–20 μm long and 7–8 μm wide, with small gland cells along their whole length and at the orifice one larger gland, 7–10 μm long, fixed (Fig. 20J). One mature egg at a time. Distribution and habitat in Korea. Mt. Hallasan, Jeju city, Jeju-do, soil and litter layers of Q. serrata coppice forests, wetland, South-East slope of Mt. Hallasan, N 33°19’23.88”, E 126°33’29.90”, 777 m asl. The Korean record confirms the associaton of this species with wet habitats.

Cognettia koreana sp. n. (Figures 2A,B, 3, 4) Type material. Holotype: NIBRIV0000860931, slide No. 2422, adult, stained, whole mounted specimen. Type locality: Mt. Deogyu, Seolcheon-myon, Muju-gun, Jeollabuk-do, Korea, soil and litter layers, Abies holophylla forest, N 35°51’34.1”, E 127°44’49.1”, 1492 m asl, 21.09.2016. Paratypes (in total, 13 specimens): NIBRIV0000860932, slide No. 2421 from type locality, NIBRIV0000860942, slide No. 2786 from locality: Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Korea, soil and litter layers, Quercus mongolica forest, N 37°42’24.78”, E 128°29’09.95”, 804 m asl, 31.10.2017. P.131.1, slide No. 2294, P.131.2, slide No. 2304, P.131.3– P.131.6, slide No. 2407–2410, P.131.7–131.8, slide No. 2417–2418, P.131.9–131.11, slide No. 2420, 2423–2424 all from type locality. ...Continued on the next page ...Continued on the next page ...Continued on the next page ...Continued on the next page ...Continued on the next page ...Continued on the next page Further material examined. Five specimens from the type locality and one specimen from Mt. Gyebangsan, only in vivo. Etymology. Named after the country where it was found. Diagnosis. (1) Small size (3–6 mm, in vivo), segments 23–26; (2) chaetae maximum 3–4 per bundle, slightly sigmoid without nodulus; (3) four pairs of nephridia preclitellarly; (4) all dorsal lobes of the three pairs of pharyngeal glands free and with ventral lobes, and 2 pairs of secondary ventral lobes in V, VI; (5) dorsal blood vessel from XII, blood colourless; (6) sperm funnel small (35–50 μm long); (7) spermatheca entally free, made of a thick-walled, 35–50 μm long and 12–17 μm wide ectal duct with a sessile ectal gland and a thin-walled ampulla; (8) some mature eggs at a time. Description. Small worm. Holotype 2.6 mm long, 225 µm wide at VIII and 255 µm at clitellum (fixed), 26 segments. Length of paratypes 3.2–6.0 mm, width 150–230 µm at VIII and 180–340 µm at clitellum in vivo, length of fixed specimens 2.3–2.6 mm, width 150–270 µm at VIII and 220–270 µm at clitellum, segments 23–26. Chaetae sigmoid, without nodulus. Chaetal formula 2,3–2,(3): 2,3,(4)–(2),3,4, length 30–37 µm in preclitellar region, 39–50 µm in posterior segments, 2.5–3 µm wide, absent in XII. Epidermal glands inconspicuous. Body wall 16–20 μm thick, cuticle 1 μm, or Brain about 100 μm long and 1.3–1.5 times longer than wide (fixed and in vivo alike), anteriorly slightly convex, posteriorly deeply incised (Fig. 3A). Three pairs of primary pharyngeal glands, all free dorsally, first pair the largest, all with ventral lobes and two pairs of secondary glands in V and VI (Fig. 3E, F, I). Chloragocytes large, 20–30 μm long in vivo (Fig. 3H). Dorsal blood vessel from XII, blood colourless. The anterior bifurcation in peristomium. Four pairs of nephridia preclitellarly from 6/7 to 9/10; anteseptale consisting of funnel only, efferent duct arises antero-ventrally (Fig. 3G) (one specimen has only three pairs of nephridia preclitellarly). Coelomocytes transparent, elongated oval, about 21–27 μm long in vivo (15–23 μm, fixed) (Fig. 3H). Pars tumida of midgut at XVIII–XX (occupying 2 segments). Seminal vesicle absent. Sperm funnels (Figs 2A, 4 A–C) small, 35–50 μm long and 1.2–1.5 times longer than wide in vivo (28–50 μm long and 1.5–2 times longer than wide in fixed specimens); sometimes stubby and slightly longer than wide (Fig. 4B); the collar as wide as funnel body or slightly narrower. Diameter of sperm ducts about 7 μm. Spermatozoa 41–48 μm long, head 20–30 μm in vivo (25–45 μm long, head 13–15 μm, fixed). Male glandular bulb (Fig. 4D, E) compact, oval, about 50 μm long, 30 μm wide in vivo (30–45 μm long and 25–45 μm wide when fixed). Spermathecae (Figs 2B, 4 G–J) confined to V, entally free. Ectal ducts thick-walled, 35–50 μm long and 12–17 μm wide in vivo [30–44 μm long (in one case 60 μm) and 8–10 μm wide, fixed] with one sessile gland (15–22 μm long, fixed) at the orifice (Fig. 4I). The ampulla thin-walled, 33–50 μm long, 17–22 μm wide in vivo (25–35 μm long, 18–25 μm wide, fixed), with sperm in the lumen. 1–4 large mature eggs at a time (Fig. 4F). Distribution and habitat. In Korea: Mt. Deogyu, Seolcheon-myon, Muju-gun, Jeollabuk-do, soil and litter layers of Abies holophylla forest, N 35°51’34.1”, E 127°44’49.1”, 1492 m asl; Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers of Q. mongolica forest, N 37°42’24.78”, E 128°29’09.95”, 804 m asl. Differential diagnosis. Seven species are similar to the new species in size and in that they reproduce only sexually: C. zicsii Dózsa-Farkas, 1989, C. lapponica Nurminen, 1965, C. bisetosa Christensen & Dózsa-Farkas, 1999, C. quadrosetosa Christensen & Dózsa-Farkas, 1999, C. floridae Healy, 1996, C. hibernica Healy, 1975 and C. baekrokdamensis (Dózsa-Farkas et al. 2018). C. pseudosphagnetorum was also assumed to reproduce only sexually by Martinsson et al. (2015a), but we disagree with this opinion. The main differences that distinguish these from the new species are the followings: C. baekrokdamensis and C. floridae have asymmetrical ectal swellings of the spermathecal ducts (which is absent in the new species). In C. bisetosa and C. hibernica, the maximum number of chaetae per bundle is two. C. quadrosetosa has 3–4 chaetae per bundle laterally, while in the new species lateral bundles have only 2–3 chaetae. In the new species, bundles of four chaetae occur only ventrally. C. lapponica and C. zicsii are slightly larger than the new species: 32–37 segments, 6–8 mm body length in C. lapponica, and 34–47 segments, 7–10 mm in C. zicsii in vivo; the sperm funnel is also larger (120–180 μm long in vivo in C. lapponica and 140–240 μm long in C. zicsii).

Bryodrilus diverticulatus Černosvitov, 1929 (Figure 11) Material examined. 17 specimens (two were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000837802, slide No. 2578, NIBRIV0000837803, slide No. 2611). This species is widespread in the northern hemisphere (Christensen & Dózsa-Farkas 2006). The Korean specimens agree with the descriptions of the species (Černosvitov 1929, Christensen & Dózsa-Farkas 1999, 2006), but are slightly smaller, 6–8 mm long, (vs. 7–12 mm in literature) 340–450 μm wide at XII in vivo, segments 30–38. Chaetae sigmoid, 2–6 per bundle (Fig. 11B). Brain straight or slightly concave posteriorly (Fig. 11A). Clitellum girdle-shaped, gland cells arranged irregularly. Two pairs of oesophageal appendages, hollow, lobed, pulsating in VI (Figs 11D, H, I). Dorsal vessel arising in clitellar region, blood colourless. 7 pairs of preclitellar nephridia (4/5–10/11). Intestine widens abruptly from VII to IX (especially in VIII–IX) then narrows in X–XII (Fig. 11C), as has been described by Černosvitov (1929). Coelomocytes discoid, transparent. Sperm funnel 60–100 μm long, 1.5–3 times longer than wide (Figs 11 E–G). Male glandular bulb variable. Spermathecae with elongate ectal ducts, ampullae slightly wider than ducts, without diverticula, with joint proximal attachment to oesophagus dorsally (Figs 11H, I). Some glands at the ectal orifices. Distribution and habitat in Korea. Mt. Deogyu, Seolcheon-myon, Muju-gun, Jeollabuk-do, soil and litter layers of Sasa borealis forest, N 35°52’17.5”, E 127°46’33.9”, 761 m asl; Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl; Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers of Q. mongolica forest, N 37°42’24.78”, E 128°29’09.95”, 804 m asl; Mt. Odaesan, Sangwonsa, Dongsan-ri, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, soil and litter layers, mixed forest, N 37°47’03.63”, E 128°33’44.06”, 906 m asl; Mt. Odaesan, Waljeongsa, Dongsan-ri, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, Korea, soil and litter layers, Abies holophylla forest, N 37°43’36.93”, E 128°35’47.48”, 630 m asl; Mt. Chiaksan, Hakgok-ri, Socho-myeon, Wonju-si, Gangwon-do, soil and litter layers of mixed forests, N 37°22’58.07”, E 128°03’30.83”, 484 m asl., Published as part of Felföldi, Tamás, Dózsa-Farkas, Klára, Nagy, Hajnalka & Hong, Yong, 2020, Three new enchytraeid species (Enchytraeidae, Annelida) from mountain soils of Korea and ten species new for the country, pp. 1-45 in Zootaxa 4896 (1) on pages 24-25, DOI: 10.11646/zootaxa.4896.1.1, http://zenodo.org/record/4358984, {"references":["Cernosvitov, L. (1929) Communication preliminaire sur les Oligochetes recoltes par M. P. Remy pendant la croisiere arctique effectuee par le \" Pourquoi-Pas? \" en 1926 sous la sirection du Dr. J. - B. Charcot. Bulletin du Museum National d'Histoire Naturelle, Paris, 2 (1), 144 - 149.","Christensen, B. & Dozsa-Farkas, K. (2006) Invasion of terrestrial enchytraeids into two glacial tundras: North-eastern Greenland and the Arctic Achipelago of Canada (Enchytraeidae, Oligochaeta). Polar Biology, 29, 454 - 466. https: // doi. org / 10.1007 / s 00300 - 005 - 0076 - 3","Christensen, B. & Dozsa-Farkas, K. (1999) The enchytraeid fauna of the Palearctic tundra (Oligochaeta, Enchytraeidae). Biologiske Skrifter, The Royal Danish Academy of Sciences and Letters, 52, 1 - 37."]}

Cernosvitoviella minor Dózsa-Farkas, 1990, sensu lato (Figure 13) Material examined. 6 specimens (two were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000860937, in 70 % ethanol). 2–3.3 mm long, 140–200 μm wide at VIII and 150–280 μm at XII, segments 19–24. Chaetae sigmoid with nodulus, up to 7–8 per bundle (Fig. 13C). The clitellum saddle-shaped, the glandular cells in transverse rows, absent ventrally (Fig. 13A). Brain incised posteriorly, about 1.5 times longer than wide. Two pairs of primary and two pairs of secondary pharyngeal glands. Dorsal vessel originating at XII or XIII, blood light pink. Anterior bifurcation in segment III (Fig. 13G). Nephridia mostly unpaired in 6/7–7/8 and 8/9 or 9/10 (Fig. 13B). Coelomocytes variable, with either coarse refractile granules (black in transmitted light) or hyaline cytoplasm (Fig. 13B). The sperm funnels cylindrical, about 30–40 μm long and 2 times longer than wide, with high collar (Figs 13A, D, E). Sperm ducts about 5 times longer than the funnels, with uniform diameter (6 μm) and without or with a small dilatation at the opening. Male pores surrounded by glands (Figs 13A, F). Spermatozoa 26–29 μm long. Spermathecae also variable but confined to V, similarly to the description of Dózsa-Farkas et al. (2017). The ampulla sphaerical, but the length of the ectal duct is variable. In some specimens, they are short (Fig. 13H), in other specimens, the ducts are much longer (Fig. 13I). Mostly one large egg is present at a time (Figs 13A, D, F). Distribution and habitat in Korea. Muljangori-oreum Wetland, Bonggae-dong, Jeju-si, Jeju-do, N 33°24’29.04”, E 126°36’23.41”, 812 m asl; Mt. Chiaksan, Hakgok-ri, Socho-myeon, Wonju-si, Gangwon-do, soil of mixed forests, Q. serrata forest, N 37°23’36.50”, E 128°03’15.30”, 395 m asl., Published as part of Felföldi, Tamás, Dózsa-Farkas, Klára, Nagy, Hajnalka & Hong, Yong, 2020, Three new enchytraeid species (Enchytraeidae, Annelida) from mountain soils of Korea and ten species new for the country, pp. 1-45 in Zootaxa 4896 (1) on page 27, DOI: 10.11646/zootaxa.4896.1.1, http://zenodo.org/record/4358984, {"references":["Dozsa-Farkas, K. (1990) New enchytraeid species from sphagnum-bogs in Hungary (Oligochaeta: Enchytraeidae). Acta Zoologica Hungarica, 36, 265 - 274."]}

Cernosvitoviella atrata (Bretscher, 1903) (Figure 12) Material examined. 11 specimens (two were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000837801, in 70 % ethanol). Our observations agree with the emended description of Dózsa-Farkas et al. (2017), but the specimens from Korea are slightly smaller: 2–4 mm long, 140–170 μm wide at VIII and 170–200 μm at XII (vs. 3–5 mm and 170–250 μm wide at clitellum), segments 19–24. Chaetae sigmoid with nodulus, up to 6–7 per bundle, 32–40 μm long. Brain incised posteriorly (Fig. 12A). Nephridial anteseptale with funnel only, postseptale with conspicuous canal, efferent duct terminal (Fig. 12D). Two pairs of primary and two pairs of secondary pharyngeal glands (Fig. 12F). Coelomocytes 14–20 μm long (Figs 12C, D), variable, mostly oval, without or with refractile granules, brown in transmitted light. Dorsal vessel origin in XII–XIII, anterior bifurcation peristomial (Fig. 12B). Blood light pink. Seminal vesicle absent. Sperm funnels conical, 55–80 μm long, vas deferens long and 15–20 μm wide proximally and gradually taper to a 8–11 μm wide duct distally (Fig. 12E). Male opening surrounded by glands. Spermatozoa 30–50 μm, heads 15–25 μm long. Spermatheca (Fig. 12F) confined to V, ampullae elongate, about as long as or slightly shorter than the length of the ectal ducts, sperm arranged lengthwise. Although Chalupský (1992) observed two forms of this species (Form I and II), which differ mainly in the shape of spermatheca, such differences were not observed by Dózsa-Farkas et al. (2017) and in this study. Nevertheless, as it was raised by Schmelz et al. (2015) based on specimens collected from Honduras, it is possible that worms currently regarded as C. atrata are members of a species complex. Distribution and habitat in Korea. Muljangori-oreum Wetland, Bonggae-dong, Jeju-si, Jeju-do, N 33°24’29.04”, E 126°36’23.41”, 812 m asl; Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl; Mt. Chiaksan, Hakgok-ri, Sochomyeon, Wonju-si, Gangwon-do, soil of mixed forests, Q. serrata forest, N 37°23’36.50”, E 128°03’15.30”, 395 m asl., Published as part of Felföldi, Tamás, Dózsa-Farkas, Klára, Nagy, Hajnalka & Hong, Yong, 2020, Three new enchytraeid species (Enchytraeidae, Annelida) from mountain soils of Korea and ten species new for the country, pp. 1-45 in Zootaxa 4896 (1) on pages 25-26, DOI: 10.11646/zootaxa.4896.1.1, http://zenodo.org/record/4358984, {"references":["Bretscher, K. (1903) Beobachtungen uber die Oligochaeten der Schweiz VII. Folge. Revue Suisse de Zoologie, 11, 1 - 21. https: // doi. org / 10.5962 / bhl. part. 75163","Chalupsky, J. (1992) Terrestrial Enchytraeidae (Oligochaeta) and Parergodrilidae (Polychaeta) from Sweden, with description of a new enchytraeid species. Zoologica Scripta, 21, 133 - 150. https: // doi. org / 10.1111 / j. 1463 - 6409.1992. tb 00316. x","Schmelz, R. M., Jocque, M. & Collado, R. (2015) Microdrile Oligochaeta in bromeliad pools of a Honduran cloud forest. Zootaxa, 3947 (4), 508 - 526. https: // doi. org / 10.11646 / zootaxa. 3947.4.3"]}

Cognettia varisetosa (Martinsson, Rota & Erséus, 2015) (Figure 15) Material examined. 8 specimens (two specimens were deposited in the National Institute of Biological Resources, Korea; NIBRIV0000837800, slide No. 2570). This species mostly reproduces by fragmentation, and this asexual reproduction is relatively fast, therefore observing sexually adult specimens is not always possible. We found only juvenile and subadult specimens, but based on the molecular analysis they are identical with C. varisetosa (see below). Length of 20 anteriormost segments 2.8–5 μm and width 260–300 μm. Worms have 3–4 pair primary and 3–4 secondary pharyngeal glands (Figs 15A, B). Chaetae sigmoid without nodulus, mostly 3 chaetae in a bundle, except some lateral preclitellar bundles which have 2 chaetae. Brain slightly concave posteriorly (Fig. 15C). Dorsal blood vessel arising in XIV–XV. First pair of nephridia at 8/9 or 9/10, efferent duct originating antero-ventrally, anteseptale consisting of funnel only. Sperm funnels were not observable. Spermathecae paired, ectal duct long with rounded glands at orifice.Ampullae oval, about 45 μm wide. Ampulla followed by a duct connecting to an ental chamber, 50 μm wide (Fig. 15D, E). Spermathecae not connected to oesophagus. Distribution and habitat in Korea. Mt. Gyebangsan, Nodong-ri, Yongpyeong-myeon, Pyeongchang-gun, Gangwon-do, Q. mongolica forest, N 37°42’27.92”, E 128°29’02.34”, 848 m asl., Published as part of Felföldi, Tamás, Dózsa-Farkas, Klára, Nagy, Hajnalka & Hong, Yong, 2020, Three new enchytraeid species (Enchytraeidae, Annelida) from mountain soils of Korea and ten species new for the country, pp. 1-45 in Zootaxa 4896 (1) on pages 28-29, DOI: 10.11646/zootaxa.4896.1.1, http://zenodo.org/record/4358984

Fridericia baradlana sp. nov. urn:lsid:zoobank.org:act: 692C37DF-0429-44CA-B989-495C256D2D43 Figs 1–3 Diagnosis The new species can be recognized by the following combination of characters: (1) medium sized (9– 15 mm in vivo); segments 42–61; (2) chaetae maximum 4–5 per bundle; (3) clitellum weakly developed, girdle shaped; (4) body wall 25–35 μm thick, cuticle thin (< 1 μm); (5) oesophageal appendages long with many branches at the end; (6) all pharyngeal glands united dorsally; (7) five pairs of preclitellar nephridia; (8) coelomo-mucocytes scarce, a/c-type, lenticytes numerous and large; (9) dorsal vessel from XIX–XXI; (10) chylus cells in XII–XIV, occupying 2 segments; (11) bursal slit T-shaped; (12) seminal vesicle in XI, not brown; (13) subneural glands in XIII–XIV; (14) sperm funnels approximately as long as half the body diameter, collar as wide as funnel body, spermatozoa 250–320 μm long, heads 110–150 μm in vivo; (15) spermatheca with two long, arm-like diverticula variously bent or bifurcate in proximal part; ectal ducts of variable length with two ectal glands and ampullae fused proximally with common opening into oesophagus. Etymology Named after the type locality, Baradla cave. Material examined Holotype HUNGARY • Baradla cave (Aggtelek Karst), entrance of Styx branch, from bits of decaying wood (these are remains of an old wooden bridge); 48°28′55.0″ N, 20°30′0.85″ E; 6 Dec. 2014; L. Dányi leg.; (F. 30. slide No. 2624, adult, stained, whole mounted specimen); ELTE. Paratypes HUNGARY • 2 specimens; same data as for the holotype (P. 128.1–128.2 slide No. 2598, 2623, adult, stained, whole mounted specimens) • all other paratypes from same type locality; 2 Oct. 2015; D. Angyal, G. Balázs & L. Dányi leg.; P. 128.3–128.5 slide No. 2086, 2643, 2644, three adult, stained, P. 128.6 slide No. 2664 only the forepart (with 26 segments) of an adult, stained, whole mounted specimens P.128.7 No. 2638 not stained, whole mounted specimens; P.128.8. slide No. 2639 (body end used for molecular analysis, DNA ID number 911b) not stained, whole mounted specimens; ELTE. Additional material HUNGARY • 2 subadult specimens; same type locality; (one of them used for molecular analysis, DNA ID number 911); only in vivo. One adult specimen was studied in vivo, stained and whole-mounted. 4 subadult specimens and 2 specimens from type locality, only in vivo. Description MEASUREMENTS. Medium-sized, whitish worms. Holotype 9.7 mm long, 370 μm wide at VIII and 380 μm at the clitellum when fixed, 53 segments. Body length of the paratypes 9–15 mm, width 300–390 μm at VIII and 360–400 μm at the clitellum in vivo; fixed specimens: length 6.6–11.3 mm, width 310–420 μm at VIII and 310–420 μm at the clitellum, segments 42–61. CHAETAE. Chaetal formula: 2,3,4–4,3,2: 2,3,4,(5)–4,(5),3,2. Inner chaetae being slightly shorter and thinner than outer: 38–40 × 5 μm and 30–35 × 2,5 μm (in preclitellar bundles). Behind the clitellum from ca. XXVII-XXXV only two chaetae per lateral bundle, posteriorly length about 45–55 × 5 μm. Often detached chaetae in coelom (Fig. 2E). HEAD PORE. At 0/I longitudinal slit. DORSAL PORES. From VII. Three or four rows of hyaline epidermal gland cells per segment. CLITELLUM. In XII–1 /2XIII, weakly developed, girdle-shaped, hyalocytes and granulocytes arranged in rows. Body wall about 25–35 μm and cuticle < 1 μm thick (Fig. 2F), in forepart slightly stronger than at the body end. BRAIN. Egg-shaped, about 160–175 μm long, about 2 times as long as wide in vivo; 130–155 μm long and 1.5–2 times as long as wide when fixed (Fig. 2A). OESOPHAGEAL APPENDAGES. Long with many branches at the end in V (Fig. 1C). All pharyngeal glands united dorsally, those in 5/6 and 6/7 with ventral lobes, the third pairs largest (Fig. 2G). CHLORAGOCYTES. From V, 20–23 μm long preclitellarly when fixed. Dorsal vessel from XIX–XXI, blood colourless. MIDGUT PARS TUMIDA. Not visible. NEPHRIDIA. Five pairs of preclitellar nephridia from 6/7 to 10/11, length ratio anteseptale: postseptale 1: 1.3–1.6, medial origin of the efferent duct. COELOMO- MUCOCYTES. Scarce, a/c-type of Möller (1971), elliptic (Figs 1D, 2B, D), length 30–40 μm in vivo. LENTICYTES. In large numbers, large 10–15 μm long (Figs 1D, 2C). Chylus cells in XII–XIV, occupying 2 segments. SEMINAL VESICLE. In XI, not brown. Sperm funnels cylindrical (Figs 2 I–K, 3A), about 150–230 μm long and about 1.5–2.3 times as long as wide in vivo. FUNNEL. Length in fixed specimens 95–150 μm, funnel body 1.2–2 times as long as wide but sometimes wider than long; collar as wide as funnel body. SPERMATOZOA. Length: 250–320 μm, heads 110–150 μm in vivo (Fig. 2 J–K); when fixed 140–170 μm and heads 80–95 μm. Diameter of sperm ducts 7–9 μm in vivo (9–10 μm, when fixed). MALE COPULATORY ORGANS. 115–140 μm long, 70–80 μm wide and 50–59 μm high in vivo (Fig. 3C); 70– 130 μm long, 50–70 μm wide and 40–60 μm high when fixed (Fig. 3B). Bursal slits T-shaped (Fig. 3D). SUBNEURAL GLANDS. In XIII–XIV (Fig. 2H). SPERMATHECAE (Figs 1 A–B, 3E–H). Two ectal glands of variable length (25–50 μm long) (Figs 3 I–J); ectal ducts contractile, thus the length variable, about 150–250 μm long and 16–17 μm wide, canal 2 μm wide in vivo (85–185 μm long, 16–17 μm wide when fixed), not widened entally, projecting into ampulla, ental bulbs about 30–40 μm wide when fixed. AMPULLAE. With two long, arm-like diverticula, in their proximal parts dividing into an upper and a lower branch and variously bent (not easily visible, since the branches are overlapping with each other). Proximal part of ampullae fused, with common opening into oesophagus dorsally. Distribution and habitat Only known from the type locality: Baradla cave, Aggtelek Karst, Hungary. Differential diagnosis There are only four valid species of Fridericia with two elongate spermathecal diverticula and with the proximal parts of the two spermathecal ampullae fused, forming one common opening into the oesophagus: F. waldenstroemi Rota & Healy, 1999, F. montafonensis Schmelz, 1998, F. profundicola Dózsa-Farkas, 1991, and F. longeaurita Boros & Dózsa-Farkas, 2015. The new species differs from all these species (leaving other characters out of consideration) by the form of diverticula, which divide into an upper and a lower finger-like branch from their base at the ampulla.

Fridericia spelaeophila sp. nov. urn:lsid:zoobank.org:act: FC10F756-F699-4776-B6DC-9C09B8A135CD Figs 1, 4–5 Diagnosis The new species can be recognized by the following combination of characters: (1) large size (body length 17–29 mm in vivo); segments 48–73; (2) chaetae maximum 5–6 (7) per bundle, many detached chaetae in coelom; (3) clitellum girdle-shaped, weakly developed; (4) body wall thick (40–60 μm) and cuticle thin (1.5–2 μm) in vivo; (5) five preclitellar pairs of nephridia; (6) coelomo-mucocytes c-type of Möller (1971), lenticytes 5–10 μm; (7) oesophageal appendages long with some branches at the end; (8) dorsal vessel from 11/12 (peculiar character); (9) seminal vesicle in XI; (10) subneural glands absent; (11) sperm funnel rounded, about ¼ as long as body diameter, collar about as wide as funnel diameter, spermatozoa 150–170 μm long, heads 50–70 μm when fixed; (12) spermatheca with 10–15 sessile diverticula with sperm in them, ectal duct of variable length with 2–3 large ectal glands of variable size; proximal part of ampullae conspicuous, fused, with common opening into oesophagus dorsally. Etymology From the composition of spelaeo (Latin: sp&emacr;laeum, i) ‘cavern’ and phila (Latin: -philus, -phila) ‘lover’, as it was collected in a cave. Material examined Holotype HUNGARY • Kis-k&odblac;háti shaft (Bükk Mts), coarse woody debris; 48°04′05.1″ N, 20°33′07.7″ E; 1 May 2018; L. Dányi & G. Balázs leg. (F.31. slide No. 2607. adult, stained whole-mounted specimen, last 11 segments used for molecular analysis, DNA ID number 1283); ELTE. Paratypes HUNGARY • 2 specimens; same data as for the holotype (P. 129.1–129.2 slide No. 2646, 2650, last 19 segments for molecular analysis, DNA ID number 1284). HUNGARY • 3 specimens; Szepesi-Láner cave system (Bükk Mts): Láner Olivér cave, debris of decaying wood and clay; 48°05’59.8” N, 20°35’41.7” E; 16 Oct. 2014; D. Angyal, G. Balázs & L. Dányi leg. (P. 130.1–130.3 slide No. 2647a+b; 2667a+b; 2085a+b) • 8 specimens; 27 Jan. 2015; D. Angyal, G. Balázs & L. Dányi leg. (P. 130.4–130.11 slide No. 2648; 2649a+b, 2651a+b; 2665a+b; 2668a+b; 2669a+b; 2670a+b; 2676a+b); ELTE. Additional material 2 juvenile specimens only in vivo from Láner Olivér cave. Three adult specimens were fixed on site, but due to the improper fixation these were not suitable for detailed morphological analysis. Description MEASUREMENTS. Large, whitish worms. Holotype 59 segments, 23.5 mm long, 0.75 mm wide at VIII and 0.80 mm at the clitellum in vivo; fixed specimen: 12.7 mm long, 0.89 mm wide at VIII and 1.0 mm at the clitellum (later from this specimen, 10 segments were taken for molecular analysis, DNA ID number 1283). Body length of the paratypes 17–27 mm, width 0.60–0.78 mm at VIII and 0.77–0.90 mm at the clitellum in vivo; fixed specimens 10–29 mm long, width 0.75–1.2 mm at VIII and 0.90–1.25 mm at the clitellum; segments 48–73. CHAETAE. Chaetal formula: 2,3,4,5,(6,7)–5,4,2: (2),4,5,6,(7)–(6),4,3,2. Mostly inner chaetae being slightly shorter and thinner than the outer ones: e.g. 50–70 × 5–7 μm and 74–100 × 9–11 μm (Fig. 4C), but sometimes placed irregularly (e.g. from one side to the other half in line: 78 × 8; 100 × 9; 100 × 9; 75 × 8, 93 × 9 μm) or almost equally long and thick in preclitellar bundles (Fig. 4E). Many detached chaetae in packages in coelomic cavity (Fig. 4F). In these packages the length of largest chaetae was 104 × 8–9 μm, the length of the smallest one 47 × 6 μm. From segment XVI or at the latest from XXII, in the lateral bundles only 2 chaetae, length about 80 × 4.5–7 μm. HEAD PORE. A longitudinal slit at 0/I (Fig. 4B). DORSAL PORES. From VII. Epidermal gland cells inconspicuous. CLITELLUM. In XII–1 /2XIII, weakly developed, girdle-shaped, gland cells irregularly arranged (Fig. 4D), between bursal slits mostly granulocytes. BODY WALL. Thick, about 35–60 μm, cuticle thin, about 1–2 μm when fixed. BRAIN (Fig. 4A). Egg-shaped, about 170 μm long, about 1.2–1.6 times as long as wide (fixed). OESOPHAGEAL APPENDAGES. Long, with some distal branches in V. All pharyngeal glands united dorsally and with short ventral lobes. CHLORAGOCYTES. From V. Dorsal vessel from 11/12 (in one case in XII), with large heart-like expansions in XI–VIII, blood colourless. CHYLUS CELLS AND MIDGUT PARS TUMIDA. Not visible (probably because the intestine was full of woodfragments and crystals (most probably calcite) in all studied specimens; Fig. 4I). NEPHRIDIA. Five pairs of preclitellar nephridia from 6/7 to 10/11, length ratio anteseptale: postseptale 1: 1.3–1.4 (Fig. 4H), adseptal origin of efferent duct. COELOMO- MUCOCYTES. c-type: with smooth outline, elliptic, matrix pale, with well visible nucleoli, 17– 26 μm long in vivo, 13–25 μm long when fixed (Figs 1E, 4G). LENTICYTES. 5–10 μm long. SEMINAL VESICLE. In XI or X–XI. SPERM FUNNELS. Mostly roundish, about 270–300 μm long and about 1.4–1.6 times longer than wide in vivo (Fig. 4K). Funnel (Figs 4 K–L, 5A) length in fixed specimens 180–300 μm, funnel body 1.2–1.4 times longer than wide, sometimes two times as long as wide; collar about as wide as funnel body (Figs 4L, 5A). Length of spermatozoa not measurable in vivo, heads 110–130 μm (Fig. 4K), in fixed specimens, spermatozoa 150–170 μm long, sperm heads 50–70 μm. Diameter of sperm ducts 8–9 μm when fixed. MALE COPULATORY ORGANS. 100–200 μm long, 90–180 μm wide and about 80 μm high when fixed (Fig. 4J), glandular body weakly developed. Bursal slits T-shaped. SUBNEURAL GLANDS. Absent. SPERMATHECAE (Figs 1F, 5 B–H). Two or three large ectal glands, size variable (35–97 μm long in vivo and 40–90 μm long, fixed); ectal ducts about 310–340 μm long and 37–38 μm wide, canal 8–8.5 μm wide in vivo (when fixed, variable: 150–300 μm long, 27–40 μm wide, canal 6–8 μm), not or slightly widened entally, projecting into ampulla, ental bulbs about 70–84 μm wide when fixed. AMPULLAE. Surrounded distally by about 10–15 sessile diverticula (Figs 5B, F, G–H), these diverticula are 50–90 μm long and 40–90 μm wide. Sperm in a circle in lumen of ampullar distal part and also in the diverticula (Figs 5B, G–H). Diameter of ampulla and diverticula together 180–300 μm when fixed. Proximal part of ampullae conspicuous, 100–320 μm long when fixed and fused into one common duct, which opens into oesophagus dorsally (Figs 5 D–E). Often the length of two the proximal part is different (e.g. 130 μm and 255 μm long). 1–2 rather small mature eggs at a time. Distribution and habitat In Kis-k&odblac;háti shaft and Szepesi-Láner cave system, in decaying wood, Bükk Mts, Hungary. Differential diagnosis The new species differs from all Fridericia species described up to now by the unusual origin of the dorsal vessel before clitellar segments (mostly in XI from septum 11/12, only in one specimen in XII). Only in the following species of Fridericia does the dorsal vessel originate in XIII (intraclitellarly) or XIV, but not preclitellarly: F. parasitica &Ccaron;ernosvitov, 1928, F. pretoriana Stephenson, 1930, F. monochaeta Rota, 1995, F sousai Schmelz, 2013 and F. cusanica Schmelz, 2003. Other differences: F. sousai and F. monochaeta are smaller (38–43 and 30–35 segments) and have only two spermathecal diverticula; F. parasitica has 40–52 segments but only 4 spermathecal diverticula; F. pretoriana has 36–51 segments and F. cusanica 32–35 segments and spermatheca without diverticula. Results of molecular analysis In total, 5, 4 and 6 new sequences were obtained from the studied Fridericia species in the case of ITS, CO1 and H3, respectively. Unfortunately, we failed to amplify the ITS region and CO1 gene from some specimens, which was probably due to the improper hybridization of PCR primer sequences to the extracted genomic DNA. Results of molecular analysis confirmed that Fridericia baradlana sp. nov. and Fridericia spelaeophila sp. nov. are distinct species, since based on the three studied regions, sequences acquired from the examined specimens were clearly separated in the phylogenetic trees (Figs 6–7).

Mesenchytraeus jungsaihoi sp. n. (Figures 12A–B, 13, 14) Type material. Holotype: NIBRIV0000810594, slide No. 2381, adult, stained specimen, anterior part of the worm opened, mounted specimen (last 12 segments, 2.45 mm; processed for DNA analysis No. 1125). Type locality: site 11. Gwaneumsa trail of Mt. Hallasan, Jeju Island, Korea, N 33&ring;41'75.9", E 126&ring;54'78.0", 634 m asl, 27.10.2016, leg. Y. Hong. Paratypes (in total 9 stained, adult specimens on slides): NIBRIV0000810595, slide No. 2278 adult, anterior 42 segments of the stained, mounted specimens. From type locality, NIBRIV0000811385, slide No. 2391, one adult, stained specimen (last 31 segments, 5.3 mm, for DNA analysis No. 1149), site 4. P.118.1.1–118.1.3. slide No. 2279 adult, stained specimen whole mounted, slide No. 2334, one adult, stained specimen (last 3 segments, 1.3 mm, for DNA analysis No. 1141), slide No. 2382, one adult, stained specimen (last 13 segments, 3 mm, for DNA analysis No. 1126) from type locality. P.118.2.1–P.118.2.2, slide No. 2390, one adult, stained specimen (last 12 segments, 2 mm for DNA analysis No. 1124), slide No. 2393a+b, anterior and posterior part of one adult, stained, mounted specimen. P.118.294 subadult, stained, whole mounted specimen anterior part opened, site 4. Further material examined. 5 juveniles from sites 2, 5 and 12. Etymology. The species is named after Dr. Jung Sai Ho who kindly supported collection in Mt. Hallasan. Diagnosis. The new species can be recognized by the following combination of characters: (1) large, wide worms (15–31 mm long and about 0.9–1 mm wide in vivo), segments 47–80; head and the body forepart dorsally with brown pigment; (2) chaetae sigmoid with nodulus, maximum 5–6 (7) per bundle, in V–X ventrally only 2–3 enlarged chaetae; (3) clitellum girdle-shaped: gland cells small, in reticulate pattern; (4) five preclitellar pairs of nephridia; (5) dorsal blood vessel from XVIII–XXI, blood light pink; (6) two pairs of primary and 3 pairs of secondary pharyngeal glands, not connected dorsally; (7) small lemon-shaped coelomocytes, light yellow in aggregations in vivo; (8) sperm sacks and egg sack may extend into XXIV and XXX; (9) atrium 190 – 250 µm long with 6–7 very large atrial glands, numerous penial glands and some slightly larger accessory copulatory glands extending around male pores; (10) spermathecae free, ectal ducts of varying length, globular ampullae with a crown of diverticula-like protrusions, ampullae continuing entally into a flexible elongate bag that ends in VII or VIII, not connected to the oesophagus. Description. Large enchytraeid worm. Colour light pink, dorsal side is light brown preclitellarly, while the prostomium is dark brown by pigmentation (Fig. 13A, C). Holotype 15.9 mm long, 1 mm wide at VIII and 1.15 mm at clitellum (fixed), segment number 68. Body length of paratypes 15–31 mm, width 700–950 µm at VIII and 820–1110 µm at clitellum in vivo; length of fixed specimens 8.5–14.5 mm, width 520–1100 µm at VIII and 620– 1500 µm at clitellum. Segments 47–80. Strong external segmentation at body end. Chaetae sigmoid with nodulus. Chaetal formula: 2,3,4,5 – 4,3,2,3,4: 3, 4,5,– 4,5,6,(7). Chaetae mostly unequal in size within a bundle: in ventral bundles a gradual increase in length towards the ventral midline and in lateral bundles an increase in length in dorsal direction. From V to IX or X only two or three stronger chaetae per bundle ventrally (sometimes 2 one side and 3 in other side, in XI always tree or four chaetae in a bundle). The length of the longest chaetae ventrally gradually increasing from II to IV (from 100 or 115 by 8.5 µm to 150–160 by 10 µm). From V to VII–IX they are larger and stronger (195–230 by 10–15 µm). In X–XI slightly smaller (195–200 by 10–12 µm). Chaetae of lateral bundles smaller and thinner than ventrals and gradually increasing from II to XI (from 112–120 × 6–7 µm to 130– 185 x 8–10 µm). Postclitellarly longest chaetae measuring 120–105 by 7–10 µm. Chaetae in XII absent. Head pore at 0/I, a large transverse slit (Fig. 13A). Clitellum girdle-shaped in XI–XII, weakly developed, gland cells small in reticulate pattern, also between bursal slits. In one case, gonadal region shifted forwards, bursal slits in X (paratype P.118.2.1 slide No. 2390). Thickness of body wall about 74–120 µm, depending on state of sexual maturity, cuticle about 2–2.5 µm, fixed. Brain incised anteriorly and slightly convex posteriorly, slightly wider than long (e.g. 105 by 110 µm, fixed) (Fig. 13B,C). Two pairs of primary pharyngeal glands (in 4/5–5/6), not united dorsally, and three or four pairs of secondary pharyngeal glands in V–VII (VIII); the secondary glands lobed (Fig. 13D). Yellow-brownish chloragocytes from IV, about 10 µm long, fixed. Dorsal blood vessel from XVIII–XXIV, anterior bifurcation in I, blood pale reddish (Fig. 13C). Five pairs of preclitellar nephridia from 6/7 to 10/11, anteseptale funnel only, postseptale lobed with folded canal, no interstitial tissue, efferent duct arising between the lobes. Oesophageal and intestinal appendages or diverticula absent. Coelomocytes only mucocytes, lemon-shaped, with granula, in cell aggregations light yellowish in vivo, small, size of cells 14–20 µm (Fig. 13D,E). Sperm sac extending backwards to XIX–XXIV, egg sack to XXIII–XXX. In sperm sack sperm bundles in rolls (Fig. 13J–L). Sperm funnel thickwalled, about 400–1250 µm long and 4–6 times longer than wide, fixed, mostly reclinate (Fig. 13H–I). Sperm duct very long, reaching as far as XVI–XIX, loosely coiled, diameter 44–65 µm (fixed); diameter gradually increasing towards atrium. Atrium 190–250 µm long, maximum width 97–150 µm, here joined by 6–7 very large atrial glands (prostate glands), usually (120 – 200 µm to 420 µm long, Figs. 12B, 14C–E). The atrium connects through a duct (90–110 µm long, fixed) with the male copulatory organ, which is surrounded by numerous penial glands (about 40 – 50 µm long) and some accessory copulatory glands (about 50 – 80 µm long) (Figs. 12B, 14F). The everted bursa may be conspicuous and domelike (Fig. 13F,G). Bursal slits large, irregular, transversal, in XII (Fig. 14A,B). Subneural glands absent. Spermathecae free (Figs. 12A, 14G–K): ectal ducts with different length, 240–260 µm long and 48–62 µm wide in vivo (85 – 180 µm long and 40–58 µm wide, fixed), devoid of glands. Spermathecal pores in 4/ 5 in lateral position. Ampullae globular with more diverticula-like protrusions, diameter 150 – 205 µm in vivo (130–190 µm, fixed). Ampullae continuing entally into a flexible elongate bag which ends in VII or VIII, not connected to the oesophagus. Eggsack with submature eggs only. It is possible that the diverticula of the spermathecae will be more distinct when the specimens are more developed sexually and with mature eggs. Unfortunately, our specimens did not reached this stadium even after half a year of culturing. Distribution and habitat. Korea, Mt. Hallasan, Jeju Island, site 2, 4, 6, 11–12: soil, moss, grass and litter layer under Abies koreana, Quercus mongolica, Sorbus alnifolia and mixed forest. Differential diagnosis. Up to now, seven valid species of Mesenchytraeus have been reported with enlarged ventral chaetae: M. tetrapodus Timm & Popchenko, 1978, M. crenobius Timm, 1994, M. kontrimavichusi Piper et al., 1982, M. gigachaetus Xie, 2012 (Shen et al., 2011, Xie 2012), M. longiductus Christensen & Dózsa-Farkas, 2012, M. anisodiverticulatus Shen et al., 2012a, M. monodiverticulatus Shen et al., 2012b and M. calyx Dózsa- Farkas, Felföldi & Hong, 2015. The main differences between these species and the new species are as follows: The spermathecae of M. tetrapodus, M. crenobius, M. gigachaetus, M. anisodiverticulatus, M. monodiverticulatus, M. longiductus and M. calyx are connected with the oesophagus but in the new species they are free. M. kontrimavichusi has also free spermathecae, but the worms are smaller, 12 mm long, 53 segments (vs. 15–31 mm long and 47–80 segments in M. jungsaihoi sp. n.) and the spermathecae have one diverticulum each; moreover there is no atrium (Timm 1994; Timm & Popchenko 1978; Piper et al. 1982; Christensen & Dózsa-Farkas 2012; Shen et al. 2011, 2012a, b; Xie 2012, Dózsa-Farkas et al. 2015). Considering all morphological characters, this species is very similar to M. calyx, by the dark-brown pigmented head, the light-pink blood, and the enlarged ventral chaetae, but apart from other differences purely on the basis of the type of spermathecae, the two species are different. It was also supported by the results of the molecular analysis.

Xetadrilus jejuensis sp. n. (Figures 12D, 15–16) Type material. Holotype: NIBRIV0000810596, slide No. 2206, adult, stained whole mounted specimen. Type locality site 7, Mt. Hallasan in Gwaneumsa trail, Jeju Island, Korea, soil and litter layers of Styrax japonica tree, N 33&ring;23'15.9", E 126&ring;32'03.3", 1306 m asl, 0 9.06.2016, leg. Y. Hong. Paratypes (in total 13 stained, adult specimens on slides and 34 specimens in 70% ethanol): NIBRIV0000810597, slide No. 2176, site 8, NIBRIV0000811386, slite No. 2396, site 8, P.119.1.1–119.1.8, slide No. 2203–2205, 2207, 2399–2402, from type locality, P.119.2.1– 119.2.2, slide No. 2397–2398, site 8, P.119.3, slide No. 2300 (last 6 segments, 0.8 mm for DNA analysis No. 1129). In 70% ethanol: P.119.4, twenty-three specimens, type locality; P.119.5 site 8 one specimen; P.119.6, site 6 one specimen; P.119.7, site 11 five specimens; P.119.8 site 12 four specimens. Further material examined: 10 specimens, only in vivo. Etymology. Named after Jeju Island. Diagnosis. The new species can be recognized by the following combination of characters: (1) small worms, 2.5–4.5 mm long, width about 130–200 µm in vivo, segments 23–31; (2) lateral chaetae present in II–VII, absent from VIII on, formula: 2,0–0: 2–2; (3) clitellum saddle-shaped: dorsally granulocytes and hyalocytes, laterally only granulocytes; (4) in prostomium at the frontal tip present a vesicle-like recess, 6–8 inner papillae and a pair of prostomial ganglia; (5) brain incised posteriorly; (6) dorsal blood vessel from XII–XIII, blood colourless; (7) pharyngeal gland with unpaired dorsal lobes in IV and V, secondary ventral lobes in V and VI spherical, in VI–VII a pair of separate elongate lobes with a “Z-like fashion”; (8) two pairs of preclitellar nephridia in 6/7– 7/8; (9) sperm funnels 60–90 µm long in vivo, 2–3 times longer than wide, collar distinct; (10) male copulatory organs small, spherical glandular bulbs diameter 35–40 µm in vivo, extra bulbs absent; (11) spermathecae free, at the orifice of ectal ducts with a sessile gland, distally widening into a narrow ampulla, the following tubes widening into thin-walled ental reservoirs in VII or VIII. Description. Small, slender worms (Fig. 15A). Holotype 2.5 mm long, 100 µm wide at VIII and 150 µm at clitellum (fixed), 23 segments. Length of paratypes 2.5–4.5 mm, width 130–180 µm at VIII and 170–200 µm at clitellum in vivo, length of fixed specimens 2.5–4 mm, width 100–150 µm at VIII and 150–190 µm at clitellum, segments 23–31. Chaetae two per bundle (Fig. 15D), straight, slightly bent proximally 17–23 µm long and 2 µm thick preclitellarly, at the hindmost segments about 33–40 µm long and 2 µm thick. Lateral chaetae present in II– VII, absent from VIII on. Ventral chaetae from II on, absent in XII, formula 2,0–0: 2–2. On the body surface pale elongate glandular cells in 7–8 transverse rows and some roundish gland cells. Clitellum XII–1 /2XIII, saddleshaped, not developed ventrally, the gland cells in about 18 transverse rows, dorsally granulocytes and hyalocytes but laterally and downwards towards the male copulatory organs only granulocytes (Fig. 15E). Prostomium similar to other Xetadrilus species, the head pore in mid-dorsal position on the prostomium (Fig. 15B). Frontal prostomial epithelium thickened, with a vesicle-like recess at the frontal tip. About 6–8 inner papillae and a pair of prostomial ganglions (15–22 µm long, fixed) present in prostomium (Fig. 15B). Prostomial musculature well developed. Body wall about 12–15 µm and cuticle 1–1.5 µm thick in vivo, septa 4/5– 9/10 thickened. * according to Schmelz et al. 2011 Brain about 90–100 µm long, 2 times longer than wide (fixed), incised posteriorly (Fig. 15C). Post-pharyngeal bulbs well developed. Perikarya of II–IV fused into suboesophageal ganglion, segmental ganglia present from V on (Fig. 15B). Pharyngeal glands (Figs. 15F, 16G–H) with unpaired dorsal lobes in IV and V, primary ventral lobes in V elongate; secondary ventral lobes in V and VI spherical, smaller than primary ventral lobes. In VI–VII a pair of separate elongate lobes, consisting of an anterior dorsal part in VI and a posterior ventral part in VI–VII; both parts broadly connected in Z-like fashion (Fig. 16G–H). Oesophageal appendages and intestinal diverticula absent, intestine widening abruptly in VII. Chloragocytes small, light brown, about 10–13 µm long in vivo. Dorsal vessel from XII–XIII, blood colourless. Midgut pars tumida from XVIII–XXI, extending over 3 segment lengths (Fig. 16C). Two pairs of preclitellar nephridia from 7/8 to 8/9, not constricted at septums; anteseptale as long as postseptale or slightly shorter, terminal origin of efferent ducts (Fig. 15G), dorsal vesicle in the postseptale absent. First postclitellar nephridia at 13/14. Coelomocytes broadly oval, ca. 16–23 µm long, distinctly dark brown in vivo, filled with small refractile vesicle (Fig. 16D,E), in fixed specimens the cytoplasma pale with well visible nucleus, 12–19 µm long (Fig. 16A). Seminal vesicle absent. Sperm funnels 60–90 µm long in vivo 2–3 times longer than wide (50–80 µm long and 2 times longer than wide, fixed), tapering distad, collar distinct, about as wide as funnel body or slightly narrower (Figs. 15E, 16D–F). Sperm ducts 6 µm wide. Length of spermatozoa 30–50 µm, heads 12–15 µm in vivo (30–40 and 7–10 µm, fixed). Male copulatory organs (Fig. 16B) small, spherical glandular bulbs diameter 35–40 µm in vivo (25–30 µm, fixed) extra bulbs absent. Spermathecae (Figs. 12D, 16G–H) not attached to oesophagus. Ectal ducts short (length 20–30 µm, diameter 12–15 µm in vivo) at the orifice with a sessile gland (Fig. 16I); distally widening into ampullae (diameter 16–17 µm), from here sperm present, which is arranged in parallel in longitudinal axis of spermatheca. The following tube narrower (diameter ca. 9 µm, 150–200 µm long in vivo), widening into thin-walled ental reservoir in VII or VIII (sometimes bent backwards into VI). The reservoir-sacks about 40–100 µm long and 10–20 µm wide in vivo and mostly filled with spheroid bodies (Fig. 16G). Mostly one large mature egg at a time. Distribution and habitat. Korea, Mt. Hallasan, Jeju Island, site 6–8, 10–12: soil and litter layers under Quercus mongolica, Styrax japonica, Quercus serrata, Sorbus alnifolia and mixed forest. Differential diagnosis. Up to now, three Xetadrilus species have been reported with dark coelomocytes: X. pitucus (Righi, 1974), X. righianus (Xie & Rota, 2001) and X. maacki Schmelz, Collado & Römbke, 2011. But in X. pitucus, all three pharyngeal glands are united dorsally, the secondary lobes are absent and the lateral chaetae are absent already from VII. In X. righianus, the secondary lobes of pharyngeal glands also absent, the clitellar glands occur also ventrally but are weakly developed and the spermathecal reservoir is globular (diameter 37–40 µm). In X. maacki, all pharyngeal glands are united dorsally, three ventral pairs of secondary lobes are present and the spermathecae are confined to V. Similar and distinguishing traits of Xetadrilus jejuensis sp.n., X. aphanoides sp. n. and X. aphanus are listed in Table 2., Published as part of Dózsa-Farkas, Klára, Felföldi, Tamás, Nagy, Hajnalka & Hong, Yong, 2018, New enchytraeid species from Mount Hallasan (Jeju Island, Korea) (Enchytraeidae, Oligochaeta), pp. 337-381 in Zootaxa 4496 (1) on pages 360-364, DOI: 10.11646/zootaxa.4496.1.27, http://zenodo.org/record/1446851, {"references":["Schmelz, R. M., Collado, R. & Rombke, J. (2011) Mata Atlantica enchytraeids (Parana, Brazil): A new genus, Xetadrilus gen. nov., with three new species, and four new species of Guaranidrilus Cernosvitov (Enchytraeidae, Oligochaeta). Zootaxa, 2838, 1 - 29.","Righi, G. (1974) Marionina pituca sp. n. (Oligochaeta, Enchytraeidae) from Brazilian soil and its intestinal parasite Buetschiella marionina sp. n. (Ciliata, Astomata). Zoologischer Anzeiger, 5 / 6, 414 - 419.","Xie, Z. & Rota, E. (2001) Four new terrestrial species of Marionina (Clitellata, Enchytraeidae) from China and re-examination of M. hoffbaueri Moller. Journal of Natural History, 35, 1417 - 1431. https: // doi. org / 10.1080 / 002229301317067610"]}

Achaeta koreana sp. n. (Figures 1, 2, 5A–C) Type material. Holotype: NIBRIV0000810584 slide No. 2210, adult, stained whole mounted specimen. Type locality: site 4, Baekrokdam crater on the summit of Mt. Hallasan, Jeju Island, Korea, soil of grass on highland in North slope (N 33&ring;21'46.0", E 126&ring;31'58.0"), 1843 m elevation, 0 9.06.2016, leg. Y. Hong. Paratypes (in total 9 stained, adult specimens on slides and 37 specimens in 70% ethanol): NIBRIV0000810585, slide No. 2198, site 1, NIBRIV0000811380, slide No. 2276, site 2, P.113.1. slide No. 2212, from type locality, P.113.2.1–113.2.3. slides No. 2193–2195, site 6, P.113.3. slide No. 2196, site 5, P.113.4.1, slides No. 2197, site 1. In 70% ethanol: P.113.5, from type locality 10 specimens; P.113.6 site 2 seven specimens; P.113.7 site 5 eight specimens; P.113.8, site 6 twelve specimens. Further material examined. 15 specimens investigated in vivo, 3 of them processed for DNA analysis. Etymology. Named after the country where it was found. Diagnosis. The new species can be recognized by the following combination of characters: (1) small, stout worms (2–3 mm long and 200–280 µm wide at clitellum in vivo), segments 17–22; (2) no pyriform glands; (3) clitellum developed only laterally: dorso-lateral area with hyalocytes in disordered three or four longitudinal rows; (4) dorsal blood vessel from VI; (5) pharyngeal glands at 4/5–5/6 connected dorsally, at 6/7 separate dorsally, the first ventral lobes separate from the dorsal lobes in IV, secondary ventral glands absent; (6) three pairs of preclitellar nephridia; (7) pars tumida of midgut from XIII–XIV, extending over 2 segments; (8) sperm funnel small, barrel-shaped, collar narrower than funnel body; (9) male pores in XII, ventrolaterally, no glandular body, only the pore surrounded by small inconspicuous glands; (10) spermathecae confined to V. Description. Small worm (Fig. 1D). Holotype 2.8 mm long, 275 µm wide at VIII and 315 µm at clitellum (fixed), 21 segments. Length of paratypes 2.5–3.8 mm, width 200–250 µm at VIII and 220–280 µm at clitellum in vivo, length of fixed specimens 2–3 mm, width 220–270 µm at VIII and 2 30–300 µm at clitellum, segments 17–22. No pyriform glands. Body wall thick, thickness dorsally 22–24 µm, cuticle 4–7 µm, ventrally 17–18 µm and 2–3 µm, respectively, in vivo (Fig. 1A). Clitellum in XII–1 /2 XIII developed only laterally, dorso-lateral areas with hyalocytes in two or three disordered longitudinal rows (Fig. 1C), hyalocytes large and conspicuous, 28–32 µm high and 17–19 µm wide, granulocytes 20–24 by 16–14 µm (Fig. 1E). Ventro-laterally only granulocytes. The dorsal interruption 60–70 µm wide in vivo, dorsal borderline consisting of granular cells only in one longitudinal row (Fig. 1B). Ventral borderlines inconspicuous. Head pore on the top of prostomium (Figs. 1F–G). Spermathecal pores at 4/ 5 in lateral position. Male pores in XII. Brain egg-shaped 1.5 times longer than wide, 80–90 µm long, fixed (Fig. 1F). The prostomial ganglion (Figs. 1F,G) well visible, 37–40 µm long (fixed). Pharyngeal glands at 4/5–6/7 (Figs. 2A, 5A), all with ventral lobes. The first and secondary dorsal lobes united dorsally, the third pair separate dorsally. Three pairs of preclitellar nephridia at 6/7–8/9 constricted by septum. Length ratio anteseptale: postseptale 1: 2.5 preclitellarly, postseptale tapers gradually into efferent duct, with small terminal vesicle (Figs. 2D–E). Dorsal blood vessel from VI (Figs. 2A, 5A). Coelomocytes about 40–53 µm long in vivo, flat, cytoplasm pale, margin with indefinite contour in top view, but spindle-shaped in side view (Fig. 2C), the length measurable only in side view. Oesophageal appendages in V, well developed without canal in IV (Figs. 2A, 5A). Chloragocytes yellowish-brown, about 15 µm long in vivo. Midgut pars tumida XIII–XIV (occupying 2 segments) (Fig. 2B). Sperm funnel small, barrel-shaped, 65–90 µm long in vivo (53–62 µm fixed), about 1.2–2 times longer than wide, collar narrower than funnel body (Figs. 2F–G, 5C). Sperm duct 6 µm thick in vivo. Spermatozoa 75–90 µm, heads 30–38 µm long in vivo (52–60 µm and 17–23 µm, fixed). Seminal vesicle absent. Male copulatory organs small, widely separate ventro-laterally, no glandular body or bursa, only the pore surrounded by small inconspicuous glands (Figs. 2H,I). Spermathecae small, free, confined to V. The short ectal duct (20–30 µm long 20–23 µm wide in vivo) has a small gland (Figs. 2L,M). In welldeveloped specimens the duct widens slightly into a narrow dilation of ampulla (25–28 µm wide). After the dilation the connecting tube (about 60 µm long and 20 µm wide) ends in an elongated globular ental reservoir (35–50 µm long, 25–35 µm wide in vivo) in V. The surface of the reservoir is granulated, sperm is visible only in the ampullar dilation and the connecting tube (Figs. 2J–L, 5B). Distribution and habitat. In Korea, Mt. Hallasan, above 1306 m elevation, at site 1–7. Differential diagnosis. Among the previously described 12 small Achaeta species without pyriform glands and the spermathecae confined to segments V–VI, none has the origin of the dorsal vessel from VI; moreover, secondary pharyngeal glands are, with one exception (A. hanagarthi Schmelz, 2008), present, and the spermathecal opening is without a small gland. In A. camerani (Cognetti, 1899) the dorsal blood vessel originates in VIII and in the all other species in VII. A. brevivasa Graefe, 1980, A. diddeni Graefe, 2007, A. hallensis Möller,1976, A. antefolliculata Dózsa-Farkas & Boros, 2005, A. afolliculata S esma & Dózsa-Farkas, 1993 and A. singularis Schmelz, 2008 have two pairs of preclitellar nephridia, further A. hanagarthi and A. paranensis Schmelz, 2008 have only one pair. Only A. pannonica Graefe, 1989, A. iberica Graefe, 1989 and A. etrusca Rota, 1995 similarly to A. koreana sp. n. have three pairs of preclitellar nephridia, as in the new species. But in A. pannonica all reproductive organs except the spermathecae are shifted one segment forward, so the male pores are in XI, while in the new species, in A. iberica and in A. etrusca they are in the usual position in XII. A. etrusca differs from A. koreana sp. n. by his paired knob-like cutaneous gland structures dorsolateral in II–VI and by the shorter spermatozoa (40 µm long, sperm heads 15 µm (Rota 2015) vs. 75–90 µm and 30–38 µm, respectively), moreover the penial bulbs are compact. Finally, in A. iberica, hyalocytes of the clitellar glands are lined in 4 distinct longitudinal rows., Published as part of Dózsa-Farkas, Klára, Felföldi, Tamás, Nagy, Hajnalka & Hong, Yong, 2018, New enchytraeid species from Mount Hallasan (Jeju Island, Korea) (Enchytraeidae, Oligochaeta), pp. 337-381 in Zootaxa 4496 (1) on pages 339-343, DOI: 10.11646/zootaxa.4496.1.27, http://zenodo.org/record/1446851, {"references":["Schmelz, R. M., Collado, R. & Rombke, J. (2008) Mata Atlantica enchytraeids (Parana, Brazil): The genus Achaeta (Oligochaeta, Enchytraeidae), Zootaxa, 1809, 1 - 35.","Graefe, U. (1980) Systematische Untersuchungen an der Gattung Achaeta (Enchytraeidae, Oligochaeta). I. Beschreibung von Achaeta brevivasa sp. n. und Achaeta camerani (Cognetti). Mitteilungen aus den hamburgischen zoologischen Muzeum und Institut, 77, 35 - 39.","Graefe, U. (2007) Achaeta diddeni sp. nov. (Enchytraeidae, Clitellata) from the northern German lowlands. Folia Facultatis Scentiarum. Nauralium Universitatis Masarykianae Brunensis, Biologia, 110, 35 - 40.","Moller, F. (1976) Achaeta hallensis nom. nov. pro Achaeta segmentata Moller, 1974. Mitteilungen aus dem Zologischen Museum in Berlin, 52, 175. https: // doi. org / 10.1071 / IS 16042","Dozsa-Farkas, K. & Boros, G. (2005) Achaeta antefolliculata sp. n., a new enchytraeid species (Oligochaeta, Enchytraeidae) from the rock grassland of the Sas-Hegy in Hungary. Acta Zoologica Academiae scientiarum Hungaricae, 51, 279 - 285.","Sesma, V. & Dozsa-Farkas, K. (1993) Description of seven new species of enchytraeidae (Oligochaeta) from Spain. Acta Zoologica Hungarica, 39, 249 - 265.","Graefe, U. (1989) Systematische Untersuchungen an der Gattung Achaeta (Enchytraeidae, Clitellata). 2. Beschreibung von vier neuen Arten. Mitteilungen aus dem hamburgischen zoologischen Museum und Institut, 86, 127 - 131.","Rota, E. (1995) Italian Enchytraeidae (Oligochaeta). I. Bollettino di Zoologia, 62, 183 - 231. https: // doi. org / 10.1080 / 11250009509356067","Rota, E. (2015) Five new species of Enchytraeidae (Annelida: Clitellata) from Mediterranean woodlands of Italy and reaffirmed validity of Achaeta etrusca, Fridericia bulbosa and F. miraflores. Journal of Natural History, 49 (33), 1 - 34. https: // doi. org / 10.1080 / 00222933.2015.1009514"]}

Xetadrilus aphanoides sp. n. (Figures 12C, 17, 18) Type material. Holotype: NIBRIV0000810598, slide No. 2179, adult, stained whole mounted specimen. Type locality site 4, Baekrokdam crater on the summit of Mt. Hallasan, Jeju Island, Korea, soil of grass on highland in North slope, N 33&ring;21'46.0", E 126&ring;31'58.0", 1843 m asl, 0 9.06.2016, leg. Y. Hong. Paratypes (in total 14 stained, adult specimens on slides and 22 specimens in 70% ethanol): NIBRIV0000810599, slide No. 2180, type locality, NIBRIV0000811387, slide No. 2310, site 2. P.120.1.1–120.1.5 slide No. 2184–2187, 2248, type locality, P.120.2.1–120.2.3, slide No. 2249–2250, 2302, site 7, P.120.3.1–120.3.3, slide No. 2311–2313, site 2, P.120.4 slide No. 2318, site 5. In 70% ethanol: P.120.5 type locality, eleven specimens; P.120.6 site 2 five specimens; P.120.7 site 7 four specimens; P.120.8 site 13 one specimen; P.120.9 site 11 one specimen. Further material examined. 11 specimens investigated in vivo, 4 of them processed for DNA analysis from site 4, 7, 11 Etymology. Named after its similarity to Xetadrilus aphanus Schmelz, Collado & Römbke, 2011. Diagnosis. The new species can be recognized by the following combination of characters: (1) small size (2.8– 4 mm in vivo), segments 20–26; (2) two chaetae per bundle, lateral chaetae absent from VIII on; (3) prostomial recess, some prostomial inner papillae and well-developed prostomial ganglia present; (4) clitellum saddle-shaped; (5) three pairs of preclitellar nephridia; (6) coelomocytes oval, pale; (7) pharyngeal glands in IV and V unpaired dorsal lobes, with ventral lobes in V, secondary ventral lobes in V and VI. The third pharyngeal glands free dorsally in VI and with a posterior ventral part in VII, 'Z'-shaped; (8) sperm funnels pear-shaped, 30–48 µm long and 1.5–2 times longer than wide; (9) male copulatory organs spherical, diameter 30–38 µm, extra bulbs absent; (10) spermathecae free, ental reservoirs in V or VI. Description. Holotype 3 mm long, 125 µm wide at VIII and 150 µm at clitellum (fixed), 24 segments. Length of paratypes 2.8–4.0 mm, width 140–180 µm at VIII and 150–220 µm at clitellum in vivo, length of fixed specimens 2.7–4.0 mm, width 140–180 µm at VIII and 150–220 µm at clitellum, segments 22–26. Two chaetae per bundle, lateral chaetae present in II–VII, absent from VIII on. Ventral chaetae from II on, absent in XII, formula: 2,0–0: 2–2. Chaetae straight or slightly bent 20–22 µm long preclitellarly, at the hindmost segments about 30–37 µm long and 2 µm thick. On the body-surface, pale inconspicuous transverse glandular rows and mostly round well-visible bright gland cells in 5–6 transverse rows (Fig. 17H). Clitellum XII–1 /2XIII, saddle-shaped, not developed ventrally (Fig. 17E), the gland cells in transverse rows, dorsally more granulocytes as hyalocytes and laterally near to the male copulatory organs only granulocytes (Figs. 17D–G). Prostomium similar to other Xetadrilus species, the head pore in mid-dorsal position on the prostomium. Frontal prostomial epithelium thickened, with a vesicle-like recess at the frontal tip. Some inner papillae and well developed prostomial ganglia observed, especially in stained specimens (Fig. 17C). Prostomial musculature well developed. Body wall about 10 µm and cuticle 1 µm thick. Brain about twice as long as wide, incised posteriorly (Fig. 17B). Suboesophageal ganglion in III–IV, perikarya of ventral nerve cord in segmental ganglia from V on. Pharyngeal glands (Figs. 17A, 18A–B) with unpaired dorsal lobes in IV and V, with primary ventral lobes in V, secondary ventral lobes in V and VI spherical, smaller than primary ventral lobes. In VI–VII a pair of separate elongate lobes, consisting of an anterior dorsal part in VI and a posterior ventral part in VI–VII; both parts broadly connected in Z-like fashion. Oesophageal appendages and intestinal diverticula absent, intestine widening abruptly at 6/7 (Fig. 17A), densely ciliated from VII. Chloragocytes small golden brown, about 12–17 µm long in vivo. Dorsal vessel from XII–XIII, blood colourless. Midgut pars tumida from XVI–XX, extending over 2–3 segment length. Three pairs of preclitellar nephridia from 7/8 to 9/10 (sometimes unpaired), not constricted at septum; length ratio anteseptale: postseptale about 1: 1.7, subterminal origin of efferent duct preclitellarly (Fig. 17I,J), terminal in postclitellar segments, dorsal vesicle in the postseptale absent. First postclitellar nephridia at 13/14. Coelomocytes elongate, broadly oval, ca. 18–25 µm long in vivo (15–17 µm, fixed), filled with pale vesicle without colour or tint (Fig. 18C). Seminal vesicle absent. Sperm funnels (Fig. 18E,F) small, pear-shaped 30–48 µm long in vivo (30–45 µm, fixed), about 1.5–2 times longer than wide, collar distinct, slightly wider than funnel body. Length of spermatozoa 40–50 µm, heads 16–17 µm in vivo (30–35 µm and 10 µm respectively, fixed). Sperm ducts 5–7 µm wide in vivo. Male copulatory organs small, glandular bulb spherical, diameter 30–38 µm in vivo (20–30 µm, fixed) extra bulbs absent (Figs. 17E, 18D). Spermathecae (Figs. 12C, 18H–J) not attached to oesophagus. Ectal ducts short (length 20–35 µm, diameter 10–13 µm in vivo) at the orifice slightly widening (about 15–16 µm) with or without a sessile gland (Fig. 18K), gradually widening into distal part of ampullae (diameter 14–17 µm), here sperm arranged in parallel in longitudinal axis of spermatheca (Fig. 18K). The following tubes narrow (diameter ca. 10 µm), widening into thin-walled ental reservoirs in V or VI; the reservoirs mostly about 40–50 µm long and 15–28 µm wide sacks and mostly filled with spheroid bodies (sperm rolls?) (Fig. 18G). Two to three mature eggs at a time. Distribution and habitat: Korea, Mt. Hallasan, Jeju Island, site 2–8, 11–13, soil, litter layers, grass or moss under Abies koreana, Sorbus commixta, Styrax japonica, Sorbus alnifolia and mixed-forest. Dominant at site 4. Differential diagnosis: Up to now, two Xetadrilus species have been reported with pale coelomocytes: X. aphanus Schmelz, Collado & Römbke, 2011 and X. fabryi Schmelz, Collado & Römbke, 2011. X. fabryi differs from the new species in some substantial traits, namely: intestinal diverticula in VII, male copulatory organ with two extra bulbs (vs. absent in X. aphanoides sp. n.). The new species is most similar to X. aphanus Schmelz, Collado & Römbke, 2011 in more traits, but the main difference consists in the number of preclitellar nephridia, three in X. aphanoides sp. n. but only two in X. aphanus. Similar and distinguishing traits of the new two species and X. aphanus are listed in Table 2.

Fridericia cf. paroniana Issel, 1904 (Figures 19A,B, 20) Material examined. 14 specimens (two were deposited in the National Institute of Biological Resources, Korea NIBRIV0000810600, slide No. 2369, NIBRIV0000810601, slide No. 2378, NIBRIV0000810602, slide No. 2379). Description. Middle large worms, body length 8.5���12.5 mm, width 240���330 ��m at VIII and 300���350 ��m at the clitellum in vivo. Length of fixed specimens 7.0��� 9.5 mm, width 210���330 ��m at VIII and 23 0���360 ��m at the clitellum. Segments 39���47. Chaetal formula: 2 ��� 2: 2 ��� 2, in the segment XII absent. Chaetae in bundles: 38���45 �� 5 ��m preclitellarly, at the body-end 40��� 55 x 5 ��m. Head pore at 0/I. Dorsal pores from VII. One or two large epidermal glands in transverse rows (Fig. 19C). Clitellum in XII���1 /2XIII, girdle-shaped, hyalocytes and granulocytes arranged in dense or indefinite rows, between bursal slits only granulocytes (Fig. 20A���B). Body wall 17���25 ��m, cuticle variable, 1���2.5 ��m, fixed. Brain egg-shaped, about 170 ��m long in vivo (115 ��m, fixed) 1.5���2 times longer than wide. Oesophageal appendages a-type, with wide lumen mostly without branches (Fig. 20E). Pharyngeal glands (Fig. 20F) in IV mostly with dorsal connection and without ventral lobes. Pairs in V with or without dorsal connection with ventral lobes, pair in VI free in dorsally, with large ventral lobes. Chloragocytes from V, 20���23 ��m long, fixed. Dorsal vessel from XVIII���XX, blood colourless. Midgut pars tumida between XXVII���XXXVI, in 4���5 segments. Five pairs of preclitellar nephridia from 6/7 to 10/11, length ratio anteseptale: postseptale about 1:2, midventral origin of efferent duct. Coelomo-mucocytes numerous, mucocytes type a (length 21���34 ��m in vivo, 25���33 ��m, fixed), lenticytes large, 9���13 ��m long (Fig. 20D). Chylus cells between XII���XVI, occupying 2���3 segments (Fig. 20H). Seminal vesicle absent. Sperm funnels (Fig. 20G) cylindrical, approximately 90���105 ��m long (in vivo and fixed), about twice as long as wide, collar slightly narrower than funnel body, spermatozoa about 115 ��m long, heads 37��� 40 ��m long, fixed. Diameter of sperm ducts 6���8 ��m, fixed. Male copulatory organs 70���90 ��m long, 45���70 ��m wide and 40���60 ��m high, fixed (Fig. 20B). Bursal slits T-shaped (Fig. 20I). Subneural glands absent. Spermathecae (Figs. 19A���B, 20K���L) variable: sometimes with "typical" shape: ectal ducts about 105���190 ��m long and 17���25 ��m wide in vivo (80���120 ��m long, 14���18 ��m wide, fixed), with large, floppy ectal gland (40���62 ��m long, fixed) (Fig. 20L); other specimens with another smaller gland (25���30 ��m) (Fig. 20J). Ampullae about 30���38 ��m wide (fixed), with two small diverticula and separate openings into oesophagus dorso-laterally (Fig. 20K). Other specimens with only one diverticulum of each ampulla or diverticula very small, even virtually not observable. In some specimens, the proximal parts of spermathecae fused entally, with a common opening into oesophagus dorsally (Fig. 20L). One to three mature eggs at a time. Distribution and habitat. In Mt. Hallasan, only one locality: site 14, in soil and litter layers of Sasa quelpaertensis forest. Remarks. Despite the differences, we think that these specimens studied now from Korea can be considered as Fridericia paroniana, but due to differences we mark it as ��� Fridericia cf. paroniana ���. The size, the segment number are about the same (the body diameter slightly thicker), chylus cells similarly in XII���XVI (2���3 segments long), midgut pars tumida in our specimens in XXVII���XXXVI (4���5 segments long), in F. paroniana in XXIII��� XXXIV (4���5 segments long) (observation of D��zsa-Farkas on Hungarian specimens). Different traits are: dorsal vessel origin in XVIII���XX (XV���XVI in F. paroniana by Schmelz 2003, but in some Hungarian specimens also were observed in XIX by D��zsa-Farkas). We detected in the F. cf. paroniana more (1���3) mature eggs at a time, but only one egg by Schmelz (2003). The main differences are the variations of spermathecae, but individuals with only one diverticulum often occur also in the European populations, as given in the original description. However, a joint opening of the spermathecae into the oesophagus has not yet been observed in F. paroniana. For the time being we maintain that, based on other characteristic traits (abundant a-type mucocytes with large lenticytes, girdle-shaped clitellum, where between the bursal slits are only granulocytes, two chaetae in all chaetal bundles, the same form of pharyngeal glands and oesophageal appendages) the Korean specimens belong to Fridericia paroniana. We aim to solve the problem with a molecular comparative study in the near future., Published as part of D��zsa-Farkas, Kl��ra, Felf��ldi, Tam��s, Nagy, Hajnalka & Hong, Yong, 2018, New enchytraeid species from Mount Hallasan (Jeju Island, Korea) (Enchytraeidae, Oligochaeta), pp. 337-381 in Zootaxa 4496 (1) on pages 367-368, DOI: 10.11646/zootaxa.4496.1.27, http://zenodo.org/record/1446851, {"references":["Issel, R. (1904) Doe nuove Fridericia. Atti della Societa Ligustica di Scienze Naturali e Geografiche, Genova, 15, 31 - 39.","Schmelz, R. M. (2003) Taxonomy of Fridericia (Oligochaeta, Enchytraeidae). Revision of species with morphological and biochemical methods. Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg, Neue Folge, 38, 1 - 415."]}

Achaeta macroampullacea sp.n. (Figures 3, 4, 5D–E) Type material. Holotype: NIBRIV0000810586, slide No. 2353, adult, stained whole mounted specimen. Type locality: site 12, Mt. Hallasan, Jeju Island, Korea, soil and litter layers of mixed forests, near to Gwaneumsa temple, N 33&ring;25'41.5", E 126&ring;33'47.2", 551 m asl, 29.09.2016, leg. Y. Hong. Paratypes (in total 14 stained, adult specimens on slides and 12 specimens in 70% ethanol): NIBRIV0000810587, slide No. 2320, NIBRIV0000811383, slide No. 2337, Soil in Yongnuni-orums, Gujwa-eup, Jeju Island, Korea, 26.10.2016, leg. Y. Hong, P. 114.1.1–114.1.4, slide No. 2275, 2354–2355 a, b, site 11, P.114.2.1–114.2.7, soil in Yongnuni-orums, Gujwa-eup, Jeju Island, Korea, 26.10.2016, leg. Y. Hong, P. 114.3, slide No. 2356, soil in bottom of Yongnuni- orums, Gujwa-eup, Jeju Island, Korea, 26.10.2016, leg. Y. Hong. In 70% ethanol: P.114.4 soil in Yongnuni-orums, Gujwa-eup, Jeju Island, Korea, 26.10.2016, leg. Y. Hong, 12 specimens. Further material examined. 8 specimens investigated in vivo, 2 of them processed for DNA analysis, one of them (spcm No. 1137, see Table 3): bottom of Yongnuni-orums, Gujwa-eup, Jeju Island, N 33°27’30.94”, E 126°49’54.90”, 193 m asl, 26.10.2016, leg. Y. Hong. Etymology. Named after the large spermathecal ental reservoir of ampulla. Diagnosis. The new species can be recognized by the following combination of characters: (1) small worms (2.5–4 mm long and 190–220 µm wide at clitellum in vivo), segments 20–26; (2) no pyriform glands; (3) clitellum developed only laterally: in dorso-lateral area the hyalocytes more or less in two longitudinal rows with granulocytes bordered, ventro-laterally the granulocytes ordered in about three longitudinal rows; (4) dorsal blood vessel from VII; (5) all pharyngeal glands connected dorsally with ventral lobes, the first ventral lobes in IV the largest, secondary ventral glands absent; (6) two pairs of preclitellar nephridia in 6/7–7/8; (7) pars tumida of midgut from XIV–XX, extending over 2–4 segments; (8) sperm funnel small, barrel-shaped, collar narrower than funnel body; (9) male pores in XII, ventro-laterally, no glandular body, only the pore surrounded by small inconspicuous glands; (10) spermathecae free, extending into VI–VII, ental reservoir large. Description. Small worm. Holotype 3.7 mm long, 200 µm wide at VIII and 230 µm at clitellum (fixed), 28 segments. Length of paratypes 2.5–4.0 mm, width 150–200 µm at VIII and 19 0–220 µm at clitellum in vivo, length of fixed specimens 2.3–3.8 mm, width 150–230 µm at VIII and 150–260 µm at clitellum; segments 20–30. No pyriform glands. One pair of small epidermal glands dorsally. Body wall dorsally 12–17 µm thick, cuticle 5–7 µm, ventrally 10–12 µm and 2.5–5 µm, respectively, fixed (Fig. 3E). Clitellum in XII–1 /2 XIII, developed only laterally, dorso-lateral areas with hyalocytes in 2 disordered longitudinal rows (Figs. 3G–H) between granulocytes. The dorsal interruption about 40–50 µm wide in vivo, dorsal borderline consisting of granular cells only in one longitudinal row, latero-ventrally the granulocytes in three or four longitudinal rows (Fig. 3H). Hyalocytes 17–20 µm high and 10–14 µm wide, granulocytes 18–22 by 8–14 µm, smaller at dorsal borderlines and between the rows of hyaline cells (16 by 10 µm) in vivo. The ventral interruption about 40–60 µm wide. Head pore on top of prostomium. Spermathecal pores at 4/ 5 in lateral position. Male pores in XII. Brain egg-shaped 80–100 µm long and about 2 times longer than wide (Fig. 3A,B). Prostomial ganglion small about 15–23 µm long, fixed (Fig. 3B). All pharyngeal glands at 4/5–6/7 united dorsally, all with ventral lobes. The first ventral lobes conspicuous (Fig. 3C,D), secondary ventral lobes absent. Septa in 4/5–6/7 thickened. Two pairs of preclitellar nephridia at 6/7, 7/8 (Fig. 3F), constricted by septum; length ratio anteseptale: postseptale 1: 2, postseptale tapers gradually into efferent duct, with terminal vesicle. Dorsal blood vessel from VII, blood colourless. Coelomocytes about 30–48 µm long in vivo, flat, cytoplasm light brown, spindle shaped in side view (Figs. 4A,B). Oesophageal appendages spongy in V, well developed without canal in IV. Chloragocytes yellowishbrown, about 14–23 µm long in vivo. Midgut pars tumida XIV–XX (occupying 2–4 segments) (Figs. 3I –J). Sperm funnel small, barrel-shaped, 70–120 µm long in vivo (50–87 µm, fixed), about 1.5–2 times longer than wide, collar narrower than funnel body and 11–15 µm high (Figs. 4C–E). Sperm duct 7–9 µm thick in vivo (5–7 µm, fixed) mostly wound into a regular spiral (Fig. 4C). Spermatozoa 48–75 µm, heads 22–30 µm long in vivo (45–55 µm and 10–20 µm, fixed). Seminal vesicle absent. Male copulatory organs small, separate ventro-laterally, no glandular body or bursa, only the pore surrounded by small inconspicuous glands (41–54 µm long, 31–38 µm wide in vivo, 35–45 µm long and 20–33 µm wide, fixed) (Figs. 4F, 5D). Spermathecae (Figs. 4G, 5E) free. The ectal duct (20–30 µm long, 12–20 µm wide) widens out to a glandular dilation of ampulla (30–60 µm long, 20–30 µm wide). The contractile narrow connecting tube (60–120 µm long, 10–13 µm wide) expands into a large ental reservoir reaching segment VI or VII (Figs. 4G–H). Sometimes one in VI the other in VII. This ental reservoir is 50–130 µm long and 30–55 µm wide in vivo. In the reservoir sperm absent, full of globules, probably oil drops (which is supported by the fact that in fixed worms this part is barely visible, since alcohol presumably dissolves oil drops). Distribution and habitat. In Korea, Mt. Hallasan, few specimens at site 11 and 12, but more common in Yongnuni-orums, Gujwa-eup, Jeju Island in mixed forests. Differential diagnosis. Among the previously described 6 Achaeta species without pyriform glands and spermathecae reaching segments VI–VII, A. littoralis Lasserre, 1968 and A. iridescens Christoffersen, 1979 are much larger (35–40 segments, length 15–20 mm and 55–60 segments with 13.5–14.5 mm, respectively, vs. 20–26 segments and 2.5–4.0 mm in A. macroampullacea sp. n.). A. hallensis has two secondary ventral lobes of the pharyngeal glands and a large seminal vesicle (vs. absent in the new species). In A. macrocyta Christensen & Dózsa-Farkas, 1999 the origin of the dorsal vessel is from VIII and in A neotropica from XIII–XV (vs. from VII). The main distinguishing feature of A. hanagarthi is only one pair of preclitellar nephridia in 7/8 (vs. two pairs in 6/ 7 and 7/ 8 in the new species).

Chamaedrilus baekrokdamensis sp n. (Figures 5H, 8–9) Chamaedrilus cf. ozenis Torii, 2015; Chen et al. 2016, pp. 276-277, Fig. 1A–D. Type material. Holotype: NIBRIV0000810588, slide No. 2330, adult, stained whole mounted specimen. Type locality: Baekrokdam crater on the summit of Mt. Hallasan, Jeju Island, Korea, soil and litter layers of Abies koreana forest in West slope, N 33&ring;21'39.2", E 126&ring;31'51.9", 1862 m asl, 0 9.06.2016, leg. Y. Hong. Paratypes (in total 6 stained, adult specimens on slides and 13 specimens in 70% ethanol): NIBRIV0000810589, slide No. 2286, from type locality, NIBRIV0000811381, slide No. 2190, site 2. P.116.1, slide No. 2289, from type locality, P.116.2.1–P.116.2.3, slide No. 2188–2189, 2191. In 70% ethanol: P.116.3. from type locality 11 specimens; P.116.4 site 11 two specimens. Further material examined. 7 specimens investigated in vivo, 4 of them processed for DNA analysis. Etymology. Named after the Baekrokdam crater where it was a very common species (at sites 2 and 3). Diagnosis. The new species can be recognized by the following combination of characters: (1) about 8–14 mm long 300–350 µm wide in vivo, segments 35–44; (2) chaetae three per bundle, slightly sigmoid without nodulus; (3) clitellum saddle-shaped; (4) three pairs of preclitellar nephridia; (5) coelomocytes elongated oval, transparent; (6) all primary pharyngeal glands free dorsally and without ventral lobes, two compact secondary glands in V and VI; (7) dorsal blood vessel from XIV, blood light pink; (8) sperm funnels cylindrical, 75–110 µm long and 2–3 times longer than wide in vivo, collars wider than funnel body; (9) male copulatory organs compact, well developed, spherical, diameter about 70–100 µm in vivo; (10) spermathecae free, confined to V, ectal ducts distally slightly widening into ampullae and the following tubes widening into thin-walled ental reservoirs in V; at the distal part of ectal ducts near ectal pore with an asymmetrical glandular swelling on its anterior face; (11) one–three large mature eggs at a time. Description. Small worm. Holotype 6.95 mm long, 330 µm wide at VIII and 350 µm at clitellum (fixed), 39 segments. Length of paratypes 8.2–13.5 mm, width 270–350 µm at VIII and 320–430 µm at clitellum, in vivo length of fixed specimens 6–7.8 mm, width 300–350 µm at VIII and 320–350 µm at clitellum, segments (30) 35– 44. Chaetae sigmoid without nodulus. Chaetal formula 3 – 3: 3 – 3, 60 µm in preclitellar region, 75–80 µm in posterior segments three per bundle in all regions, absent in XII. Epidermal glands inconspicuous. Body wall 30– 40 µm thick, cuticle about 1.9–2.5 µm, longitudinal muscle layer well-developed (Fig. 8C). Clitellum extending over XII– ½ XIII, saddle-shaped, absent midventrally with about 100 µm distance. Clitellar gland cells irregularly scattered (Figs. 8A–B). Head pore 0/I. Brain (Figs. 8D–E) about 150 µm long and 2 times longer than wide (fixed and in vivo), anteriorly slightly convex, posteriorly incised. Three pairs of primary pharyngeal glands, all free dorsally, without ventral lobes and two pairs of compact secondary glands in V and VI (Figs. 8H, 9C–D). Intestine widening in IX. Chloragocytes about 18–28 µm long. Dorsal blood vessel from XIV, blood light pink; the anterior bifurcation in peristomium (Fig. 8G). Three pairs of preclitellar nephridia from 6/7 to 8/9; anteseptale consisting of funnel only, efferent duct arises antero-ventrally (Fig. 8I). Coelomocytes (Fig. 8F) transparent, elongated oval, about 35–40–(55) µm long in vivo (13–15 µm, fixed). Midgut pars tumida not observed. Seminal vesicle small, unpaired in XI, not brown. Sperm funnels (Figs. 8J, 9A–B) cylindrical 75–110 µm long and 2–3 times longer than wide in vivo (60–80 µm long and 1.5–2 times longer than wide in fixed specimens; sometimes stubby and about 1.3 times longer than wide only; Fig. 8J). The collars well-developed 10–18 µm high and wider than the funnel body. Diameter of sperm ducts 6–7 µm. Spermatozoa 70–80 µm long, heads 30–50 µm in vivo. Male glandular bulb compact, well developed spherical, diameter about 70–100 µm in vivo (60–85 µm, fixed). Spermathecae (Figs. 5H, 9E–F) confined to V. Ectal ducts thick-walled, 90–100 µm long and 13–18 µm wide in vivo (50–80 µm long and 16–19 µm wide, fixed), distally widening slightly into ampullae (diameter 22–25 µm in vivo), from here and further entally sperm present, arranged in parallel in longitudinal axis of spermatheca. The following tubes 60–80 µm long, slightly narrower, ca. 12–15 µm in vivo (50–80 µm long, 16–18 µm wide, fixed), widening into thin-walled ental reservoirs in V. The reservoirs thin-walled, 35–55 µm long, 1.2–1.5 times longer than wide, with few sperm in lumen. Sometimes the ampulla as wide as the ducts, i.e. not observable. At the distal part of ectal ducts the asymmetrical glandular swelling 47–52 µm long and 35–37 µm high in vivo (Figs. 5H, 9G). The canal of ectal ducts 3 µm wide. Near to the opening some smaller glands also observable (Fig. 9G). One–three large mature eggs at a time. Distribution and habitat. In Korea, at site 2, 3 (dominant) and 11, in soil, moss and litter layers under Abies koreana forests and Sorbus alnifolia. Differential diagnosis. Among the previously described Chaemadrilus species only one species Ch. floridae (Healy, 1996) has an asymmetrical ectal swelling of the spermathecal ducts as in Ch. baekrokdamensis sp. n. The new species is similar to this species in many other characters, e.g. size, number of chaetae, type of pharyngeal glands, but the principal differences of Ch. floridae to the new species are as follows: sperm funnel 4–5 times longer than wide, and the collar narrower than funnel body vs. only 2–3 times longer than wide and the collar well developed and wider than the funnel body; the coelomocytes are 14–32 µm long, round or oval, finely granular and with prominent nucleus, but larger (35–40–55 µm long in vivo), transparent, elongated oval without conspicuous nucleus in the new species and near to the spermathecal ectal orifice some glands observable, which are present in Ch. baekrokdamensis sp. n. Moreover the first pair of preclitellar nephridia at 6/7 but the number of preclitellar nephridia is not known in Ch. floridae, similarly the first pair at 6/7 and the number of preclitellar nephridia are known (3 pairs) in the new species. Ch. ozenis Torii, 2015 also similar to the new species in more traits (e.g. size, number of segments, number of preclitellar nephridia, the size of sperm funnel), but the most important difference is the absence of asymmetrical glandular swelling at the distal part of ectal ducts. In contradiction, Ch. cf. ozenis described by Chen et al. (2016) is probably identical with Ch. baekrokdamensis sp. n. based on the figures and description, since it has similar size (9–12 mm long 39–42 segments vs. 8.2–13.5 mm, 35–44 in the new species), number of chaetae, identical pharyngeal glands, both have 3 pairs of preclitellar nephridia, the sperm funnel about the same size and 2–3 times longer than wide, and the form of spermathecae is also similar (especially in Fig. 1C of Chen et al. 2016) with the asymmetrical glandular swelling at the distal part of ectal ducts. [It should be noted that in the paper of Chen et al. (2016), in the text Fig. 1. belongs to Ch. cf. ozenis but according to the legend of Fig. 1, it is Ch. cf. lapponicus, erroneously].

Enchytronia seongpanakiensis sp. n. (Figures 5G, 10, 11) Type material. Holotype: NIBRIV0000810592, slide No. 2252, adult, stained whole mounted specimen. Type locality: site 13, Mt. Hallasan, Seongpanak trail, Jeju Island, Korea, mixed-forest, N 33&ring;22'16.0", E 126&ring;33'51.6", 1352 m asl, 17.08.2016, leg. Y. Hong. Paratypes (in total 12 stained, adult specimens on slides and 9 specimens in 70% ethanol): NIBRIV0000810593, slide No. 2257, NIBRIV0000811384, slide No. 2364, from type locality. P.117.1.1–117.1.10, slide No. 2251–2256, 2363, 2365–2367 from type locality. In 70% ethanol: P117.2, from type locality 9 specimens. Further material examined. 10 specimens investigated in vivo, 3 of them processed for DNA analysis. Etymology. Named after the Seongpanak trail where it was found. Diagnosis. The new species can be recognized by the following combination of characters: (1) small size (2.4– 4 mm in vivo), segments 22–25; (2) two chaetae per bundle but lateral chaetae absent in IX– XI; (3) large prostomial recess frontally; (4) clitellum in XII–XIII, only laterally; (5) brain incised posteriorly; (6) three pairs of preclitellar nephridia; (7) chloragocytes very large; (8) pharyngeal glands in IV and V united dorsally with ventral lobes in V, in VI free dorsally with large ventral lobes; (9) dorsal blood vessel from XII, blood light pink; anterior bifurcation in peristomium; (10) intestinal diverticula absent; (11) sperm funnels pear-shaped, 35–50 µm long in vivo; (12) male copulatory organs oval (26–32 µm long in vivo); (13) spermathecae attached to the oesophagus, ectal ducts 83–100 µm long, ampulla inconspicuous. Description. Small worm. Holotype 3.15 mm long, 170 µm wide at VIII and 200 µm at clitellum (fixed), 23 segments. Length of paratypes 2.4–4.0 mm, width 175–220 µm at VIII and 21 0–240 µm at clitellum in vivo, length of fixed specimens 2.9–3.5 mm, width 130–170 µm at VIII and 140–200 µm at clitellum, segments 22–24. Chaetae straight with ental hook, ectally sharply pointed (Fig. 10H), formula 2,0 – 2: 2 – 2. Laterally two chaetae from II– VIII, absent from IX preclitellarly, in XII absent laterally and also ventrally. Ventrally 2 chaetae per bundle; length ca. 23–28 µm, diameter ca. 2.5 µm; posteriorly increasing in size to 28–35 µm. (In one case, 3 and 4 chaetae were visible in ventral chaetal bundles at IV, V, probably replacement chaetae.) The frontal prostomial epithelium with a large vesicle-like recess at the frontal tip (Fig. 10C). Head pore at 0/I (Fig. 10C). Epidermal gland cells not seen. Body wall ca. 9–15 µm thick, preclitellarly thicker, cuticle inconspicuous Brain about 80–100 µm long, 1.7–1.9 times longer than wide (fixed), incised posteriorly (Figs. 10A–B). Postpharyngeal bulbs well developed (Fig. 10J). Perikarya of II–IV fused into suboesophageal ganglion, segmental ganglia present from V on. Perikarya not only in the segmental ganglia (Fig. 10D). Pharyngeal glands united in IV and V dorsally, primary ventral lobes in V; glands separate in VI, with large ventral lobe (Figs. 10 I –J). Secondary ventral lobes absent. No oesophageal appendages, no intestinal diverticula. Chloragocytes with conspicuous vesicles from IV, dense layer from VII, very large cells (Fig. 11A), diameter ca. 29–50 µm in vivo and 25–38 µm, fixed. Coelomocytes one type, mucocytes flat or spindle shaped in lateral view, slightly longer than wide, length ca. 26–36 µm in vivo (18–32 µm, fixed) filled with fine pale vesicles (Fig. 10F–G). Gradual transition from oesophagus to intestine. Intestinal diverticula in VI not visible. Midgut pars tumida in XVII–XVIII, occupying 1–2 segment lengths, mostly not visible because of large chloragogen cells. Dorsal blood vessel from XII, blood light pink (Fig. 11A). Anterior bifurcation in peristomium (Fig. 11B). In some specimens, from the dorsal bifurcation a short branch is oriented forward (Fig. 11C). Three pairs of preclitellar nephridia, at 7/8–9/10. Anteseptale with parts of nephridial body, no constriction at septum, postseptale slightly longer than anteseptale; tapers into short efferent duct, no terminal vesicles (Figs. 10D–E). Clitellum in XII–XIII, only laterally developed (Figs. 10 K–L, 11E), i.e. absent dorsally and ventrally; cells in 27–32 separate rows. On either side between the granulocytes also hyalocytes in one or two longitudinal rows, which are not in contact with each other. The hyalocytes about 15–18 by 11–14 µm in size (Fig. 10L). Seminal vesicle absent, spermatozoa ca. 25–37 µm long, heads 9–18 µm long in vivo (25–35 µm and 10–15 µm, respectively, fixed). Sperm funnel small, pear-shaped, 35–50 µm long in vivo (27– 40 µm, fixed) and 1.2–2.2 times longer than wide, collar conspicuous, about 5–10 µm high and slightly narrower than the funnel body (Figs. 11F–H). Diameter of vas deferens ca. 5 µm. Male pore surrounded by small glands, 26– 32 µm long, 19–26 µm wide in vivo (17–26 µm long, 15–23 µm wide, fixed). Male pores apparently on body surface (Fig. 11E), no bursa or bursal slits distinguished. No subneural glands. Spermathecae (Figs. 5G, 11J) proximally attached to the oesophagus, probably separately in V (the proximal part not visible because of large pharyngeal glands). Ectal ducts 46–65 µm long, 7–12 µm wide in vivo (35–45 µm long and 10–14 µm wide, fixed), no ectal gland, ampulla inconspicuous, ellipsoid mostly may not be distinctly set off from the ectal duct, if it is separable, diameter 8–12 µm wide in vivo (13–18 µm, fixed). Sperm not well visible. One or two large mature eggs at a time. In living specimens, often more unusual glandular sacculae visible on the ventral side (Figs. 11I, K). We have not seen similar bodies in any other enchytraeid species. Unfortunately, they are not visible in fixed and stained specimens. Distribution and habitat. In Korea, only in one sample (at site 13), mixed-forest in Seongpanak trail, Mt. Hallasan, 1352 m elevation. Differential diagnosis. The new species differs from other Enchytronia species (except E. pygmaea Graefe & Schmelz, 2017) by the absence of the intestinal diverticula in VI, but we place it in the genus Enchytronia Nielsen & Christensen, 1959 because of the shape and arrangement of chaetae, absent laterally from IX to XI, by the posteriorly incised brain, the peristomial bifurcation of the dorsal blood vessel, the overall shape of the spermathecae, and only laterally developed clitellum and origin of the dorsal vessel at clitellum. Similarly, E. pygmaea did not have intestinal diverticula but it is clearly separate from Enchytronia seongpanakiensis sp. n. in the following main respects: smaller size (1.5–1.9 mm long, 17–19 segments vs. 2.4–4.0 mm, 22–25 segments), presence of only one lateral chaeta in postclitellar positions (vs. two chaetae), only one pair of preclitellar nephridia (vs. three pairs), and the posteriorly rounded brain (incised in the new species).

Bryodrilus hallasanensis sp. n. (Figures 5F, 6, 7) Type material. Holotype: NIBRIV0000810590, slide No. 2199, adult, stained whole mounted specimen. Type locality: Mt. Hallasan in Gwaneumsa trail, Jeju Island, Korea, soil and litter layers of Sorbus commixta tree, N 33&ring;22'06.8", E 126&ring;32'02.2", 1694 m asl, 0 9.06.2016, leg. Y. Hong. Paratypes (in total 18 stained, adult specimens on slides and 47 specimens in 70% ethanol): NIBRIV0000810591, slide No. 2177, from type locality, NIBRIV0000811382, slide No. 2377, site 4, P.115.1.1-115.1.6, slides No. 2174-2175, 2178, 2200-2202, from type locality, P.115.2.1-115.2.8 slides No. 2181-2183, 2258, 2373-2376, site 4, P.115.3, slide No. 2327, site 2, P.115.4, slide No. 2328, site 8. In 70% ethanol: P115.5, from type locality, three species P.115.6, site 2 one specimen; P.115.7, site 4 35 specimens; P.115.8, site 6 one specimen; P.115.9, site 11 six specimens; P.115.10, site 12 one specimen. Further material examined. 16 specimens investigated in vivo, 4 of them processed for DNA analysis. Etymology. Named after the mountain where it was found. Diagnosis. The new species can be recognized by the following combination of characters: (1) small size (5–8 mm in vivo), segments 30–40; (2) chaetae maximum 4–5 per bundle, slightly sigmoid without nodulus; (3) conspicuous epidermal gland in 5–6 rows; (4) four pairs of preclitellar nephridia; (5) coelomocytes oval or discoid with fine granules; (6) pharyngeal glands free dorsally and with ventral lobes; (7) two pairs of irregularly lobed oesophageal appendages in VI, with small canals; (8) sperm funnels pear-shaped, 70–120 µm long and 2–3 times longer than wide; (9) seminal vesicle small; (10) male copulatory organs spherical, diameter about 60–80 µm; (11) spermathecae communicating with oesophagus, ectal ducts 60–90 µm long and 13–18 µm wide, the ampullae lemon-shaped, diameter 20–30 µm, ectal gland absent. Description. Small lively worm. Holotype 5.2 mm long, 240 µm wide at VIII and 250 µm at clitellum (fixed), 35 segments. Length of paratypes 5–8 mm, width 200–260 µm at VIII and 2 40–330 µm at clitellum in vivo, length of fixed specimens 2.9–5.2 mm, width 170–220 µm at VIII and 210–250 µm at clitellum, segments (24) 30–40. Chaetae slightly sigmoid, without nodulus. Chaetae in a bundle arranged in asymmetric fan of unequal size, those towards dorsal and ventral midlines of body gradually smaller; largest ventral chaetae in a bundle preclitellarly 33– 37 µm, the next in line 34–30 µm, 29–25, and 28–23 µm long and 1.8–2 µm wide. In terminal segments the largest chaetae slightly longer, 40–45 µm. Chaetal formula 2,3,4 – 3: 3,4,(5) – 4,3 (2). Chaetae absent at XII. In ventral preclitellar bundles usually 4 chaetae, 5 in some bundles in some specimens from site 4. Epidermal gland cells conspicuous preclitellarly, 5–6 rows per segments (Fig. 6A). Head pore at 0/I, a longitudinal slit. Body wall 20–30 µm thick, cuticle thin about 1 µm, longitudinal muscle layer well-developed. Clitellum from XII–1 /2 XIII, hyalocytes and granulocytes in rows dorsally, hyalocytes larger than granulocytes, the latter often triangle-shaped (Fig. 6B), absent ventrally (about 70 µm distance) (Fig. 7G). Brain 95–110 µm long and 1.7–2.2 times longer than wide (fixed and in vivo), anteriorly slightly convex, posteriorly rounded (Fig. 6C–D). Pharyngeal glands 3 pairs in IV–VI, mostly all free dorsally with ventral lobes (Fig. 6H), sometimes first pair connected dorsally. Oesophageal appendages (Figs. 6H, 7A–B) in VI, two pairs of irregularly lobed bodies (about 30–50 µm long) attached to oesophagus ventro-laterally with small canals (these canals collapse under longer examination in vivo and give a homogeneous aspect of the structure). Intestine widening abruptly in VII and VIII (Fig. 6E). Four pairs of preclitellar nephridia from 6/7 to 9/10; anteseptale consisting of funnel only, medial rise of efferent duct (Figs. 6F,G). Coelomocytes nucleate, oval or discoid, about 15–26 µm long in vivo (13–17 µm, fixed), finely granulated (Fig. 7C,D). Dorsal blood vessel from XIII, blood colourless. Anterior bifurcation in peristomium (Fig. 6C). Pars tumida of midgut XX–XXVI, occupying 2–3 segments. Chloragocytes from VI, about 12–18 µm large. Seminal vesicle small in XI. Sperm funnels (Fig. 7E,F) pear-shaped, 70–120 µm long and 2–3 times longer than wide in vivo (60–95 µm long and 1.5–2 times longer than wide in fixed specimens). The collars well developed, as wide as funnel body or narrower. Diameter of sperm ducts 6–8 µm. Spermatozoa 70–85 µm long, heads 22–30 µm in vivo. Male glandular bulb spherical, diameter about 60– 80 µm in vivo (40–70 µm, fixed) (Fig. 7G,I). Bursal slits longitudinal, bent laterally. Subneural glands absent. Spermathecal ectal ducts about 60–90 µm long and 13–18 µm wide in vivo (50–80 µm long and 12–14 µm wide, fixed), no ectal glands, the ampullae lemon-shaped, diameter 20–30 µm in vivo and 22–25 µm, fixed. The ental ducts merging entally and with joint opening into oesophagus in VI (Figs. 5F, 7J). 1–3 mature egg at a time. Distribution and habitat. In Korea, Mt. Hallasan, sites 2, 4–6, 8, 11, 12. Dominant at sites 4, 5. Differential diagnosis. Among the previously described Bryodrilus species, four species have fewer than 40 segments and 7 mm length in vivo: B. librus (Nielsen & Christensen, 1959), B. diverticulatus &Ccaron;ernosvitov, 1929, B. tunicatus Dózsa-Farkas & Christensen, 2002, B. archipelagicus Christensen & Dózsa-Farkas, 2006, but clearly separate from this species in the following main characters: B. librus has 5 pairs of preclitellar nephridia, the oesophageal appendages are rounded, well visible and the midgut pars tumida can be found more forward (in XVII–XX), while the new species has only 4 pairs of preclitellar nephridia, the oesophageal appendages are lobed, not easily seen and the midgut pars tumida occupies 2–3 segments (in segments XX–XXVI). B. diverticulatus differs by 5 pairs preclitellar nephridia and hollow and pulsating oesophageal appendages. B. tunicatus has larger sperm funnels (200–300 µm long 4–5 times longer than wide vs. 70–120 µm and 2–3 times longer than wide, in the new species) and spermathecae with sessile diverticula in which the spermatozoa are arranged in smaller bundles. The spermathecae of B. archipelagicus are more conspicuous: the ectal duct is 220 µm long and approximately 30 µm wide and the diameter of ampullae is 90–95 µm (the ducts has a size of 60–90 to 13–18 µm and the ampullae 20–30 µm in B. hallasanensis sp. n.).

Cernosvitoviella farkasi sp. n. (Figures 1 A, 2–4) Holotype. C4 slide No.1064, adult, stained whole mounted specimen. Type locality. Kȏszeg Mts., near to the Sphagnum mire, 47o24.180N 16o33.531E, 349 m asl, in a young Scots pine forest with Molinia, mud, leg. K. Dózsa-Farkas, J. Farkas, Z. Tóth, 21.05.2014. Paratypes (in total 59 specimens). P.89.1–89.13 slides No 1037, 1039–1042, 1044–1045, 1062–1063, 1065, 2150–2151, 2220, 19 stained specimens from type locality, 21.05.2014. P.89.14, 19 specimens from type locality, in 70 % ethanol, 21.05.2014. P.89.15, 11 specimens from type locality, 13.10.2014. P.89.16, 10 specimens from type locality, in 70 % ethanol, 24.10.2016. Further material examined. 22 living specimens, not fixed, from the type locality. Etymology. Named in honour of our colleague, Dr. János Farkas, who assisted many times in recent sampling campaigns. Diagnosis. The new species can be recognized by the following combination of characters: (1) small size (body length 3–5 mm, in vivo), segments 22–26; (2) maximum 6–8 sigmoid and nodulate chaetae per bundle; (3) clitellum developed only laterally; (4) two or three unpaired nephridia preclitellarly; (5) coelomocytes spindleshaped, with refractile granules, black under transmittent light; (6) 2 + 2 pharyngeal glands; (7) sperm funnel cylindrical, large, approximately 2/3 as long as body diameter, collar conspicuous, slightly narrower than the funnel body; (8) sperm ducts considerably widened in the middle; (9) male copulatory organs large, pores surrounded by gland cells; (10) spermathecae free, reaching VII–IX segments, consisting of ectal ducts, hemispherical parts with sperm and long wide ampullae; the distal part of ectal ducts with conspicuous widenings. Description. Holotype 3.0 mm long, 160 µm wide at VIII and 205 µm at clitellum (fixed), 25 segments. Length of paratypes 3–5 mm, width 140–230 µm at VIII and 200–310 µm at clitellum in vivo, length of fixed specimens 1.8–3.8 mm, width 130–160 µm at VIII and 170–220 µm at clitellum, segments 22–26. Chaetae slender, sigmoid, with nodulus; number of chaetae per bundle variable, up to 6–8 in ventral preclitellar bundles, length 28– 35 µm. Chaetae in XII absent. Head pore at 0. Clitellum only laterally in XII–1 /2XIII, gland cells in dense rows or irregularly distributed (granulocytes about 10–13 µm long and 7–8 µm wide (fixed), the hyalocytes slightly smaller and fewer). Thickness of body wall about 12 µm in vivo, (9 µm when fixed), cuticle very thin. Brain deeply cleft posteriorly, about 100 µm long and two times longer than wide when fixed (Fig. 2 A). In prostomium, about 12 inner papillae (Figs. 2 A,B) similar to those found in Xetadrilus (Schmelz et al. 2011). This trait of Cernosvitoviella species is mentioned for the first time here. Oesophageal appendages and intestinal diverticula absent. Two pairs of primary pharyngeal glands in 4/5 and 5/6, dorsally without or with narrow connection, two secondary glands free in V and VI. (Fig. 4 D). Chloragocytes from V and forming a dense layer from VI, individual cells relatively large (22–55 µm long) and containing refractile oil droplets in vivo (Fig. 2 G). Midgut pars tumida in XV–XIX, occupying 2–3 segments (Fig. 2 E). Dorsal vessel from XII or in front of XIII, blood slightly pink, the anterior bifurcation in peristomium. 2–3 mostly unpaired preclitellar nephridia from 6/7 or 7/8, anteseptale small with funnel only, postseptale with conspicuous canals, efferent duct terminal (Fig. 2 F). Coelomocytes spindle-shaped with dark refractile granules, 36–60 µm long, 7–8 µm wide in the middle in vivo (Figs. 2 C,D). In fixed specimens they are only 20–22 µm long, the granules are not visible but the nucleus is large. Seminal vesicle large in X–XI (Fig. 3 A). Sperm funnels cylindrical, large (Figs. 2 I, 3A,C), about 90–180 µm long in vivo (80–155 µm, fixed) and 2–3 times longer than wide, about 3/4 of body diameter; collar distinct, tall and slightly narrower than the funnel body. Spermatozoa about 70 µm long, heads 25 µm, in vivo (40–60 µm and 10–20 µm, fixed, respectively). Sperm ducts considerably widened in the middle (Figs. 2 I, 3B,C,D). This thick-walled dilation about 120–180 µm long, 30–50 µm wide and the canal is 17–26 µm wide in vivo (100–180 µm, 23–34 µm and 14–17 µm, fixed, respectively). Tracts of the sperm duct before and after the dilation of about the same length as the dilated part; just after the sperm funnel duct is slightly thinner, diameter about 8–13 µm until the dilation, while the part after the dilation is 13–19 µm wide, finally slightly dilated again in the male copulatory organ, up to 15–20 µm in vivo. Male copulatory organs large, the male pore surrounded by glands forming a round and compact mass (Figs. 3 B,C,D,E), diameter 60–90 µm in vivo (60–70 µm, fixed). Subneural glands absent. Spermathecae free (Figs. 1 A, 2H, 4A.B,D), ectal glands absent. Spermathecae consist of ectal ducts (about 170 µm long and 10 µm wide in vivo, and fixed alike) widened ectally to up to 25 µm in vivo (20 µm, fixed) (Figs. 3 F,G, 4C). The ectal ducts in VI widens into almost hemispherical parts with sperm in them (25–32 µm wide in vivo and fixed alike) (Figs. 3 G. 4A). These bulbiform parts continue in long ducts which expand into wide sack-like ampullae (30–50 µm wide, in vivo and fixed alike). Ampullae reaching VII–IX segments when fully developed (Figs. 2 H, 4A,B). In the subadult specimens the hemispherical parts absent and the ampullae smaller, expanding only to VI or VII. One mature egg at a time. On the body wall surface, often epibiotic ciliates attached, similar to other Cernosvitoviella species (Figs. 2 I, 3H). Distribution and habitat. Known only from the type locality. Differential diagnosis. The new species is clearly distinguished from the rest of hitherto described Cernosvitoviella species by the prominent dilatation in the middle part of the vas deferens. C. farkasi sp. n. is most similar to C. aggtelekiensis in size, the type of coelomocytes, and the remarkable dilatations of the vasa deferentia (Figs. 3 B–D vs. Figs. 5 I,J). However, in the new species coelomocytes are narrower (Figs. 2 C,D vs. Figs. 5 E,F), the dilatations of the vasa deferentia are located more proximally, and they are more conspicuous and refracting. The spermathecal ectal duct of C. aggtelekiensis has also a widening distally, but the ampullae reach only into V or VI (Figs. 1 B, 6D–F). In five Cernosvitoviella species (C. sphaerotheca Healy, 1975, C. briganta Springett 1969, C. palustris Healy, 1979, C. estaragniensis Giani, 1979 and C. ampullax Klungland & Abrahamsen, 1981), the spermathecae also extend into VIII or IX, but in these species the dilatations of the vasa deferentia are absent or smaller, or they occur distally if present.

Cernosvitoviella crassoductus D��zsa-Farkas, 1990 (Figures 1 D, 9) Cernosvitoviella crassoductus D��zsa-Farkas, 1990: 269 ���271, figs. 7���10. Timm 1999: 134 ���135, 2 textfigs Material investigated: 3 specimens from site 10 (13.05.2011). Body 3���4 mm long, 160 ��m wide at VIII and 320 ��m at XII, segments 19���23. Chaetae sigmoid with nodulus, up to 6���8 per bundle, 44���49 ��m long. Brain deeply incised posteriorly, about 120 ��m long and 100 ��m wide in vivo (Fig. 9 A). Two pairs primary and two pairs secondary pharyngeal glands. Secondary glands without lobes and larger than the primary glands (Fig. 9 D). Coelomocytes plum-stone-shaped, 20���26 ��m long, transparent, with some refractile granula, but not dark in transmittent light (Fig. 9 C). Blood light-pink, dorsal vessel origin in XII. The anterior bifurcation in peristomium (Fig. 9 B). Seminal vesicle absent. Sperm funnels (Fig. 9 E) small, pearshaped 40���48 ��m long and 23���30 ��m wide, collars as wide as the diameter of funnel bodies, about 8 ��m high. Dilatation of vas deferens proximally just after the funnel, 90���120 ��m long and 20���23 ��m wide (the diameter of canal 10���13 ��m). After the dilatation (i.e. towards male pore) duct about 85���90 ��m long and 9 ��m wide. Male pore surrounded by a mass of glands about 50���55 ��m wide. Spermatozoa 20���23 ��m long, heads 10 ��m. Spermathecae (Figs. 1 D, 9F) short, confined to V. Ampullae elongate-oval, 45���55 ��m long and 20���22 ��m wide, with distinct sperm-containing lumen. Ectal duct 45���80 ��m long and 10���14 ��m wide, not widened at the orifice., Published as part of D��zsa-Farkas, Kl��ra, Csit��ri, Bianka & Felf��ldi, Tam��s, 2017, A new Cernosvitoviella species (Clitellata: Enchytraeidae) and its comparison with other Cernosvitoviella species from Sphagnum mires in Hungary, pp. 322-338 in Zootaxa 4254 (3) on page 330, DOI: 10.11646/zootaxa.4254.3.2, http://zenodo.org/record/546814, {"references":["Dozsa-Farkas, K. (1990) New enchytraeid species from Sphagnum-bogs in Hungary (Oligochaeta: Enchytraeidae). Acta Zoologica Academiae Scientiarum Hungaricae, 36 (3 - 4), 265 - 274.","Timm, T. (1999) A guide to the Estonian Annelida. Naturalist's Handbooks 1. Issued by the Estonian Naturalists' Society. Estonian Academy Publishers, Tartu-Tallin, 208 pp."]}

Cernosvitoviella minor D��zsa-Farkas, 1990 sensu lato (Figures 1 E���F, 10) Cernosvitoviella minor D��zsa-Farkas, 1990: 271 ���272, figs. 11���14. Rota & Healy 1999: 34 ���35, figs. 1 D��� E. Schmelz & Collado 2010: 59. Material investigated: (in total 41 specimens), 4 specimens from site 1, 3 and 4 (13.10.2014), 7 specimens from site 2 (21.05.2014 and 13.10.2014), 20 specimens from site 6 (31.03.2014), 3 specimens from sites 8 and 9 (31.03.2014), 5 specimens from site 10 (13.05.2011), 2 specimens from site 11 (20.06.2016). Body 2���3.3 mm long, 140���200 ��m wide at VIII and 150���280 ��m at XII, segments 19���22. Chaetae sigmoid with nodulus, up to 6���7���(8) per bundle. The clitellum, when well-developed, saddle-shaped, the glandular cells in transverse rows interrupted ventrally (Fig. 10 F). In the prostomium about 8���10 large, rounded papillae (Fig. 10 B). Brain (Fig. 10 A) slightly incised posteriorly, about 85���90 ��m long and 1.5 times longer than wide. Two pairs primary and two pairs secondary pharyngeal glands (Fig. 10 J). Dorsal vessel originating at XII or XIII, blood lightpink or colourless. Interestingly, the anterior bifurcation not in peristomium, as in other Cernosvitoviella species, but in segment III (Fig. 10 C) (observed only in two cases, not studied in all specimens, so requiring further studies). Nephridia mostly unpaired in 6/7���7/8 and 8/9 or 9/10. Coelomocytes are very variable: Originally they were described by D��zsa-Farkas (1990) as spindle-shaped, with coarse refractile granules (black in transmittent light). Later Rota & Healy (1999) found that the coelomocytes are variable in shape and colour (dark and hyaline). In the case of specimens studied here, this trait was also variable. Sometimes all coelomocytes were granulated and dark, while in other specimens there were spindle-shaped or oval-dark and hyaline cells alike. Hyaline cells are usually concentrated in the forepart of the body, while the majority of dark cells are found in the posterior part (Fig. 10 D,E). Sperm funnels cylindrical, about 30���40 ��m long and 2 times longer than wide, with high collar (Fig. 10 G). Sperm duct about 5 times longer than the length of funnels, diameter uniform (6 ��m) and without or with a small dilatation at the opening. Male pores surrounded by glands. Spermatozoa 25���29 ��m long, heads 12���13 ��m. Spermathecae also variable but confined to V. Ampullae spherical, length of the ectal duct can varying: In some specimens, ducts are very short (11���20 ��m long and the diameters of ampullae are 14���20 ��m (Figs.1 E, 10H,J)), in other specimens, the ducts are much longer (50���55 ��m long) and ampullae are also larger: diameter 23���25 ��m and here the sperm is arranged mostly crosswise in the lumen (Figs.1 F, 10I). In some cases, intermediate states were also found (e.g., duct 28 ��m long, ampulla 22 ��m wide). In all samples were found specimens with long and short ectal ducts alike., Published as part of D��zsa-Farkas, Kl��ra, Csit��ri, Bianka & Felf��ldi, Tam��s, 2017, A new Cernosvitoviella species (Clitellata: Enchytraeidae) and its comparison with other Cernosvitoviella species from Sphagnum mires in Hungary, pp. 322-338 in Zootaxa 4254 (3) on pages 333-334, DOI: 10.11646/zootaxa.4254.3.2, http://zenodo.org/record/546814, {"references":["Dozsa-Farkas, K. (1990) New enchytraeid species from Sphagnum-bogs in Hungary (Oligochaeta: Enchytraeidae). Acta Zoologica Academiae Scientiarum Hungaricae, 36 (3 - 4), 265 - 274.","Rota, E. & Healy, B. (1999) A taxonomic study of some Swedish Enchytraeidae (Oligochaeta), with descriptions of four new species and notes on the genus Fridericia. Journal of Natural History, 33, 29 - 64. https: // doi. org / 10.1080 / 002229399300461","Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82 (1), 1 - 176."]}

Fridericia sphaerica sp. n. (Figures 1 E–G, 2 G–I, 4, 5) Type material. Holotype. NIBRIV0000320518, slide No. 1114, adult specimen, stained whole mount. Type locality: site 1. College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do, Korea, 35 º 50 '59.0"N 127 º07' 56.4 "E, 55 m asl, soil and litter layers of woodland, leg.Y. Hong, 19.05. 2014. Paratypes. NIBRIV0000320519, NIBRIV0000320520, 2 adult specimens in 70 % ethanol from type locality, 19.05. 2014. P. 105.1–105.11. 11 adult, fixed, stained whole mounts, slides No. 1003, 1109–1111, 1115–1117, 1123– 1125, 1174, from type locality. P. 105.12. One adult, fixed, stained whole mount, slide No. 1101, site 7: Dongjinmyeon, Buan-gun, Jeollabuk-do, Korea, 35 º 46 '04.6"N 126 º 43 ' 14.8 "E, 23 m asl, garden (planting garden tree), agronomical fields, leg. Y. Hong, 19.05. 2014. P. 105.13–105.14, slides No. 1167–1168, two fixed stained whole mounts from site 13: Gyeongju National Park Buddhist Center, Korea, 35 º 52 '032"N 129 º 13 ' 21 "E, leg. Sándor Mahunka, 0 9.12. 1990. P. 105.15, six specimens in 70 % ethanol from site 1, P. 105.16, six specimens in 70 % ethanol from site 7. Further material examined. 8 specimens from sites 1, 6, and 7. Etymology. Named after the shape of spermathecal ampulla ('sphaera' = sphere, Latin). Diagnosis. The new species can be recognized by the following combination of characters: (1) large size (13– 21.5 mm long, 400–630 µm wide at clitellum in vivo, but the cuticle thin, in vivo), separate openings into oesophagus. Description. Holotype 15.8 mm long, 410 µm wide at VIII and 420 µm at clitellum (fixed), segments 60. Body length of paratypes (11)– 13–21.5 mm, width 330–450 µm at VIII and 400–630 µm at clitellum, in vivo, length of fixed specimens 10–15.8 mm, width 420–580 µm at VIII and at clitellum, segments 47–64. Chaetal formula: (2)3,4 – 4,3, 2: 3,4(5) – 4,3,(1) 2. As in other Fridericia species, the chaetae within a bundle arranged in pairs with the outer pair and thicker than the inner pair (52– 63 x 5 Μm vs. 33– 35 x 3–4 Μm, preclitellar bundles). Lengths about the same in postclitellar segments but between XVIII–XX often only the two smaller chaetae present. Two chaetae per bundle from about XXI–XXVI; chaetae gradually increasing in size posteriad from 65 Μm to 90– 95 x 5 Μm in terminal segments. Detached chaetae often present in the coelom. Head pore at 0/I. Dorsal pores from VII. Epidermal gland cells arranged in 2–3 transverse rows per segments (Fig. 4 D). Clitellum in XII– 1 / 3 XIII, girdle-shaped, hyalocytes and granulocytes arranged in dense rows dorsally (Fig. 2 G), between the bursal slits only granulocytes (Fig. 4 B,C). Body wall thick, 40–50 µm, cuticula thin ( Brain egg-shaped (Fig. 4 A), 150–190 Μm long in vivo, about 2 times longer than wide. Oesophageal appendages (Fig. 1 E) with few short branches at the end. All pairs of pharyngeal glands united dorsally and with ventral lobes, lobes in VI longest. Chloragocytes from V. Dorsal vessel from XVII–XXIII (mostly XVIII–XX), blood colourless. Midgut pars tumida not seen. Five pairs of preclitellar nephridia from 6 / 7 to 10 / 11; length ratio anteseptale: postseptale 1: 1.2–1.3, midventral origin of efferent duct, anteseptale often brown in transmitted light. Coelomo-mucocytes with fine granular matrix and clearly visible nucleus, type c (sometimes a/c), length mostly 25–53 µm (Fig. 4 E), sometimes with coarser granulation (Fig. 4 F), lenticytes small and scarce (4–8 Μm long, in vivo). Chylus cells (Fig. 4 G) between XIII–XVI, occupying 2–3 segments. Seminal vesicle large (X–XI or XI– XII). Sperm funnels cylindrical (Figs. 1 F, 2 H, 4 H, 5 A), 200–370 µm long, in vivo and 1.5–2.7 times as long as wide. In fixed specimens the length of funnels 180–260 µm. Collar slightly narrower than funnel body. Spermatozoa long, length 400–600 µm, heads 150–170 µm, in vivo. Diameter of sperm ducts about 10 µm, in vivo. Male copulatory organs (Fig. 4 C) 100–220 µm long, 60–90 µm wide and 60–80 Μm high, in vivo (100 –170, 50– 90 and 40–90 µm, respectively fixed), the laterally bent bursal slits are longitudinal or H-shaped. No subneural glands. Ectal ducts of spermathecae very long, length 380–620 µm and width 24–35 µm, in vivo (300–500 µm long, and 20–25 µm wide, fixed), gland absent at the ectal opening (Fig. 5 E). Ampullae large, onion-shaped without diverticula, diameter 95–150 µm, in vivo (fixed 90–130 µm), ental bulbs (56–70 µm wide, in vivo), projecting into the lumina of ampullae, sperm in circles around the bulbs (Figs. 1 G, 2 I, 5 B). Ectal duct canal describing spiral loops inside the ental bulbs before entering the ampullae (Figs. 1 G, 2 I, 5 B,C), a characteristic trait similar to F. perrieri. Ampullae often with granular texture (Fig. 5 D). Distal and proximal parts of ampullae considerably set off by a constriction, the proximal part about 70–130 µm long, in vivo, separate openings into oesophagus. Spermathecae enlarged in one specimen: ectal ducts 621 µm long and 36 µm wide, diameter of ampulla 199 µm, ental bulb 90 µm wide, in vivo. One to three mature eggs at a time. Distribution and habitat. In Korea, site 1, College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do, Korea, 35 º 50 '59.0"N 127 º07' 56.4 "E, 55 m asl, woodland. Site 7, Dongjinmyeon, Buan-gun, Jeollabuk-do, 35 º 46 '04.6"N 126 º 43 ' 14.8 "E, 23 m asl, garden (planting garden tree), agronomical fields. Site 11, Sulchon-myeon, Muju-gun, Jeollabuk-do 35 º 59 ' 28.7 "N 127 º 50 ' 46.8 "E, 544 m asl, mixed forest. Site 1, collected in 2007, Soil and litter layers in College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do 35 ° 50 ' 51.1 "N 127 °08' 0.3 "E, maple trees cultivation of experimental farm (= Fridericia sp. 1 in Dózsa-Farkas & Hong 2010, Table 1). Site 13, Gyeongju National Park Buddhist Center 35 º 52 '032"N 129 º 13 ' 21 "E. Differential diagnosis. Among the previously described Fridericia species with more than 40 segments, onion-shaped spermathecal ampulla without diverticula and separate openings into oesophagus, five species (F. paratalassia Schmelz, 2002, F. peregrinabunda Michaelsen, 1913, F. seoraksani Christensen & Dózsa-Farkas, 2012, F. callosa (Eisen, 1878) and F. tuberosa Rota, 1995) are similar to the new species (Schmelz 2003; Christensen & Dózsa-Farkas 1999; Rota 1995; Christensen & Dózsa-Farkas 2012). The main differences are as follows: in F. parathalassia, the spermathecal ampullae are similarly large [70–100 Μm (Schmelz 2003), 100–200 Μm (Nielsen & Christensen 1959)], but there are only four pairs of preclitellar nephridia and subneural glands are present. The main differences of F. peregrinabunda to the new species are only two chaetae in the bundles and a smaller diameter of the spermathecal ampullae (60–70 Μm). These two species were found also together with F. seoraksani. F. seoraksani can be easily distinguished from F. sphaerica sp. n. by the following characters: by their smaller size (7.2–14.4 mm long, in vivo and 37–45 segments), by the smaller diameter of spermathecal ampulla (50–60 Μm) and by the smaller sperm funnel (160–190 Μm long, in vivo). F. callosa (as redescribed in Schmelz 2003) and the new species resemble each other in more traits (e.g. similar size, form of spermatheca, long spermatozoa, large seminal vesicle, the locality of chylus cells), but F. callosa has a thick cuticle (3–5 Μm, vs. less than 1 Μm in the new species) and never 4 chaetae in the dorso-lateral bundles. Moreover the chaetae are often absent in several bundles, the third pharyngeal glands are not united dorsally and the oesophageal appendages are much branched. In F. tuberosa diverticula-like protrusions may appear on the spermathecal ampullae, spermathecal ectal glands and subneural glands are present, and the coelomocytes are of type b.

Mesenchytraeus calyx sp. n. (Figures 6 H–K, 9, 10, 11) Type material. Holotype. NIBRIV0000320525, slide No. 1173 a+b, adult, stained and whole-mounted specimen, anterior part of the worm opened dorsally, fixed 23.02. 2015. Type locality: site 8: Mt. Cheontae, Yeongdong-gun, Cheungcheongnam-do, Korea, 36 º09' 29.8 "N 127 º 36 ' 49.8 "E, 248 m asl, soil and litter layers of broad-leaved forest, leg. Y. Hong, 15.05. 2014. Paratypes. NIBRIV0000320526, slide No. 2005, adult, stained whole mounted, anterior part of the worm opened. NIBRIV0000320527, one adult specimen in 70 % ethanol, both from site 11: Sulchon-myeon, Muju-gun, Jeollabuk-do, Korea, 35 º 59 ' 28.7 "N 127 º 50 ' 46.8 "E, 544 m asl, soil and litter layers of forest, leg. Y. Hong, 16.05. 2014. Fixed 15.04. 2015. P. 107.1–107.2, slides No. 1156 a+b; 2002 a+b two adult, stained, whole mounted specimens, site 11: Sulchon-myeon, Muju-gun, Jeollabuk-do, Korea, 35 º 59 ' 28.7 "N 127 º 50 ' 46.8 "E, 544 m asl, soil and litter layers of forest, leg. Y. Hong, 16.05. 2014. Fixed 18.02. 2015 and 26.03. 2015. P. 107.3–107.8, slides No. 1149 a+b, 1155 a+b, 1157 a+b, 1162 a+b, 1163 a+b, 2003 a+b, six adult, stained specimens, anterior part of the worms opened dorsally, fixed 17.02 – 26.03.2015, from site 1: College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do, Korea, 35 º 50 '59.0"N 127 º07' 56.4 "E, 55 m asl, soil and litter layers of woodland, leg. Y. Hong, 19.05. 2014. P. 107.9 – 107.10, slide No. 1181, 2004a+b, two adult, stained specimens, anterior part of the worm opened dorsally, fixed 15.04. 2015, from type locality. P. 107.11, slide No. 2006, one juvenile specimen, fixed 26.03. 2015, from type locality. Further material examined. 1 specimen in 70 % ethanol from site 8 and 5 juveniles from sites 1, 11 and 8. Etymology. Named after the cup-shaped spermathecal ampulla (calyx = cup, Latin). Diagnosis. The new species can be recognized by the following combination of characters: (1) large wide worms (27–42 mm long and about 0.9–1 mm wide, in vivo), segments 60–84; head and the body dorsally brown pigmented; (2) chaetae sigmoid, with nodulus, maximum 6–7 per bundle, in VII–X ventrally only 2–3 enlarged chaetae; (3) clitellum girdle-shaped: gland cells small, in reticulate pattern; (4) five preclitellar pairs of nephridia; (5) dorsal blood vessel from XXIII–XXV, blood light pink; (6) two pairs primary and 3 pairs secondary pharyngeal glands, not connected dorsally; (7) small lemon-shaped coelomocytes, light yellow in aggregations in vivo; (8) sperm sacks and egg sack may extend into XXX and XLI; (9), atrium long with 5–6 very large atrial glands, numerous accessory copulatory glands of different size extending around male pores; (10) spermathecae with long ectal ducts, projecting deeply into the cup-shaped ampullae, which have 7–9 diverticula; ental ducts connected with oesophagus in V–VII. Description. Large enchytraeid worm. Colour light pink, dorsal side is light-brown preclitellarly, while the prostomium is dark brown by pigmentation (Fig. 9 A–C). Holotype 20.7 mm long, 900 µm wide at VIII and 960 µm at the clitellum, fixed, 83 segments. Body length of paratypes 27–42 mm, width 850–1000 µm at VIII and 1005– 1050 µm at clitellum, in vivo. Length of fixed specimens 20–39 mm, width 900–1050 µm at VIII and 960–1250 µm at clitellum. Segments 60–84. Strong external segmentation at body end (Fig. 10 C). Chaetae sigmoid with nodulus. Chaetal formula: 2,3, 4 – 3,2,4,5,(6): 4,5,6,2, 3 – 4,5,6,(7,3,2). Chaetae mostly unequal in size within the bundle: in ventral bundles a gradual increase in length towards the ventral midline and in lateral bundles increase to the dorsal direction. The length of the longest chaetae gradually increasing from II to VI (from 100 or 125 x 8–10 µm to 150–170 x 9–10 µm). From VII to XI only 3 or 2 chaetae in ventral bundles (rarely 4 in XI), they are larger and stronger (200–240 x 15–18 µm). Chaetae of lateral bundles smaller and thinner than ventrals (about 103–150 x 10–12 µm). Postclitellarly longest chaetae measuring 150–190 x 9–10 µm. Chaetae in XII absent. Head pore at 0/I, a large transverse slit (Figs. 9 C, 10 A). Clitellum girdle-shaped in 1 / 2 XI –XIV, extending over 2.5–3 segments (up to four segments, slide No. 1149), gland cells small in reticulate pattern, also between bursal slits (Figs. 10 B, 11 B). In one case gonadal region shifted forwards by 4 segments: clitellum in 1 / 2 VII – 1 / 2 X, bursal slits in VIII (paratype P. 107.7 slide No. 1163 a). Thickness of body wall about 80–150 µm, depending on state of sexual maturity, cuticle about 1–2 µm, fixed. Brain incised anteriorly and slightly convex posteriorly, slightly longer than wide (about 150 x 180 µm, fixed) (Figs. 6 H, 10 A). Two pairs of primary pharyngeal glands (in 4 / 5 – 5 / 6), not united dorsally, and two or three (four in the holotype) pairs of secondary pharyngeal glands in V–VI or V–VII (VIII); the secondary glands lobed (Fig. 10 E). Yellow-brownish chloragocytes (Fig. 9 A,D) from IV, about 20–25 µm long, fixed. Dorsal blood vessel from XXIII–XXV, anterior bifurcation in I, blood pale reddish. Five pairs of preclitellar nephridia (Fig. 10 D) from 6 / 7 to 10 / 11, anteseptale funnel only, postseptale lobed with folded canal, no interstitial tissue, efferent duct arising between the lobes. Oesophageal and intestinal appendages or diverticula absent. Coelomocytes only mucocytes, lemon-shaped, with granula, in cell aggregations light yellowish in vivo, small, size of cells 16–21 µm. Sperm sac (Fig. 9 A,B) extending backwards to XXII–XXX, egg sack to XXV–XLI. In sperm sack many sperm bundles (Fig. 10 F), about 88–110 µm long, with spermatozoal heads at one end, 26–30 µm long and 23–28 µm wide (Fig. 6 I). Sperm funnel thick-walled, about 500–600 µm long and 2 times as long as wide, fixed, the collar widely opened and bending outwards (Fig. 11 C), often longer on side. Sperm duct very long, reaching as far as XV–XVII, loosely coiled, diameter 35–40 µm, fixed; diamaeter gradually increasing towards atrium. Maximum width of atrium 90–120 µm, here joined by 5–6 very large atrial glands (prostate glands), usually 250–350 µm long, up to 600–700 µm (Figs. 6 K, 10 H, 11 A). The atrium connects through a duct (120–210 µm long and 40–45 µm wide, fixed) with the male copulatory organ, which is surrounded by many accessory copulatory glands of different size (Figs. 6 K, 10 G, 11 A). The everted bursa may be remarkable (Fig. 11 A). Bursal slits large, irregular, transversal, in XII (Fig. 11 B). Subneural glands absent. Spermathecae (Figs. 6 J, 9 D, 11 D,E): ectal ducts long (400– 820 µm long and 40–65 µm wide), devoid of glands. Spermathecal pores in 4 / 5 in lateral position as wavy transverse gaps (Fig. 11 F). Ampullae mostly in VI but sometimes in V or VII. Lengths of ectal ducts often unequal, e.g. when one ampulla lies in V and the other one in VI or VII. Ducts projecting deeply into the cup-shaped ampullae (their length inside ampulla 150–200 µm, width at the end about 50 µm) (Figs. 6 J, 11 E). Ampullae 250– 350 µm long, 200–260 µm wide. Ectal end of ampullae with an ectally oriented collar of about 7–9 pointed diverticula of various length (100–200 µm) (Figs. 6 J, 11 D,E). In one case (slide No. 1155) we can see these diverticula from above and count the number of diverticula (Fig 9 E). Spermatozoa appear to be hanging out from the wall of diverticula (Fig. 9 F). Ampullae continuing entally into a flexible elongate bag which ends in VI or VII, here apparently connected to the oesophagus. Eggsack with submature eggs only. Distribution and habitat. In Korea site 1: College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do, 35 º 50 '59.0"N 127 º07' 56.4 "E, 55 m asl, woodland; site 8: Mt. Cheontae, Yeongdong-gun, Cheungcheongnam-do 36 º09' 29.8 "N 127 º 36 ' 49.8 "E, 248 m asl, forest; site 11: Sulchon-myeon, Muju-gun, Jeollabuk-do, 35 º 59 ' 28.7 "N 127 º 50 ' 46.8 "E, 544 m asl, mixed forest. Differential diagnosis. Up to now, seven valid species of Mesenchytraeus have been reported with enlarged ventral chaetae: M. tetrapodus Timm & Popchenko, 1978, M. crenobius Timm, 1994, M. kontrimavichusi Piper et al., 1982, M. gigachaetus Xie, 2012 (a replacement name for M. megachaetus Shen et al., 2011), M. longiductus Christensen & Dózsa-Farkas, 2012, M. anisodiverticulatus Shen et al., 2012, and M. monodiverticulatus Shen et al., 2012. The main differences between these species and the new species are as follows: M. kontrimavichusi is smaller (12 mm long, 53 segments), spermathecae have one diverticulum each, and there is no atrium; M. crenobius has two spermathecal diverticula and the dorsal blood vessel origin in the clitellar region. M. tetrapodus has only one enlarged chaeta per ventral bundle, six pairs of preclitellar nephridia and the spermathecae attached to the oesophagus in IX–X; M. gigachaetus is smaller (10–13 mm long, 31–50 segments) and without atrial glands; the spermathecae of M. anisodiverticulatus have two asymmetrical diverticula with short ental ducts attached to the oesophagus in V, and atrial glands are absent; M. monodiverticulatus is smaller (6–10 mm, 39–58 segments), has more (4–5) enlarged chaetae in V–VI, one spermathecal diverticulum, and no atrial glands. M. longiductus is smaller (7.5–15 mm long, 48-55 segments), spermathecae are onion-shaped devoid of diverticula, and there are only two large atrial glands (Timm 1994; Timm & Popchenko 1978; Piper et al. 1982; Christensen & Dózsa-Farkas 2012; Shen et al. 2011, 2012a, b; Xie 2012). The spermathecae of M. mirabilis Eisen, 1878 are slightly similar to the spermathecae of the new species, but the ectal ducts are very short and the diverticula are roundish, moreover enlarged chaetae are absent (Eisen 1879; Christensen & Dózsa-Farkas 1999).

Dózsa-Farkas, Klára, Felföldi, Tamás, Hong, Yong (2015): New enchytraeid species (Enchytraeidae, Oligochaeta) from Korea. Zootaxa 4006 (1): 171-197, DOI: http://dx.doi.org/10.11646/zootaxa.4006.1.9

Achaeta spp. We found two Achaeta species: one with and another one without pyriform glands. Unfortunately there were very few individuals present in the samples and it was not possible to study all characters, so the first species was named only Achaeta sp. The second species had many traits in common with A. brevivasa Graefe, 1980, and is described in the following.

Fridericia granulocyta sp. n. (Figures 6 D – G, 8) Type material. Holotype. NIBRIV0000320523, slide No. 1094, adult, stained and whole-mounted specimen. Type locality: site 7: Dongjin-myeon, Buan-gun, Jeollabuk-do, Korea, 35 º 46 '04.6"N 126 º 43 ' 14.8 "E, 23 m asl, soil of agronomical fields, leg. Y. Hong, 19.05. 2014. Paratypes. NIBRIV0000320524, slide No. 2026, adult stained whole mounted specimen. Locality: site 11: Sulchon-myeon, Muju-gun, Jeollabuk-do, Korea, 35 º 59 ' 28.7 "N 127 º 50 ' 46.8 "E, 544 m asl, mixed forest, leg. Y. Hong, 16.05. 2014. P. 106. 1– 5, slides No. 2007 –2010, 2016. 2 adult and 3 subadult stained whole mounts, from type locality, leg. Y. Hong, 19.05. 2014. P. 106.6–106.8, slides 2024, 2025, 2027. 3 adult whole mounts, stained specimens, from site 11, Sulchon-myeon, Muju-gun, Jeollabuk-do, Korea, 35 º 59 ' 28.7 "N 127 º 50 ' 46.8 "E, 544 m asl, mixed forest, leg. Y. Hong, 16.05. 2014. Further material examined. 4 subadult specimens from type locality. Etymology. Named after the granulated coelomo-mucocytes. Diagnosis. The new species can be recognized by the following combination of characters: (1) Medium-sized worms (7–12 mm, in vivo), segments 40–47; (2) maximum 5 (6) chaetae per bundle; (3) clitellum girdle-shaped, between male openings only granulocytes; (4) five preclitellar pairs of nephridia; (5) all pharyngeal glands with ventral lobes; (6) coelomo-mucocytes type b, lenticytes scarce; (7) chylus cells in XII–XIV (2 segments); (8) seminal vesicle absent; (9) subneural glands absent; (10) sperm funnel small, barrel-shaped, collar narrower as funnel body; (11) spermathecae with onion-shaped ampullae (diameter 34 – 47 µm, in vivo) without diverticula, separate opening into oesophagus, spermathecal ectal duct somewhat shorter than body diameter, no ectal glands. Description. Holotype 8.5 mm long, 320 µm wide at VIII and 330 µm at clitellum, fixed, 44 segments. Body length of paratypes 7–11.5 mm, width 290 – 380 µm at VIII and 300–400 µm at clitellum, in vivo. Length of fixed specimens 6–12 mm, width 300–400 µm at VIII and 310–420 µm at clitellum. Segments 40–47. Chaetal formula: 3,4 – 4,3, 2: 4,5,(6) – 5.4,3,2. Largest chaetae in preclitellar bundles 55 – 60 x 5 µm, intermediate-sized chaetae 48 – 50 x 5 µm, smaller inner chaetae 25 – 35 x 4 µm. At body end chaetae measuring 65– 75 x 5–6 µm. Chaetae in XII absent. Head pore at 0/I. Dorsal pores from VII. Epidermal gland cells arranged in 1–3 transverse rows per segment, often one or two rows per segment brown-colored. Clitellum in XII– 1 / 2 XIII, girdle-shaped. Gland cells arranged in rows, between male openings only granulocytes. Thickness of body wall about 32–42 µm, cuticle about 2 µm in fixed specimens. Brain egg-shaped, about 120 Μm long (fixed) and 1.7 times longer than wide (Fig. 8 A). Oesophageal appendages type a, with some small branches at the end (Fig. 6 D). First pair of pharyngeal glands united dorsally, the secondary and third pairs separate dorsally (sometimes all three separate), all with ventral lobes the smallest lobes in IV. Chloragocytes from V about 14–20 Μm long, in vivo. Dorsal vessel from XVI–XVIII, blood colourless. Midgut pars tumida not seen. Five pairs of preclitellar nephridia from 6 / 7 to 10 / 11, anteseptale large, length ratio anteseptale: postseptale 1: 1.3–1.4, adseptal origin of efferent duct, no terminal vesicle (Fig. 8 G). Coelomomucocytes (Figs. 6 E, 8 C) broadly-elliptical, cell periphery with refractile granules, type b, length 22–40 Μm, lenticytes scarce, 5–9 Μm long, in vivo. Chylus cells between XII–XIV, occupying 2 segments. Seminal vesicle absent. Sperm funnels mostly barrel-shaped, small (Figs. 6 G, 8 E,G), about 90–150 µm long and 1.5–1.8 times as long as wide, in vivo. Funnel length in fixed specimens about 100 µm. Collar 12–20 Μm, high and narrower than funnel body. Spermatozoa about 80–160 µm long, heads 40–60 µm, in vivo (Fig. 8 G). Diameter of sperm ducts 5– 7 µm, fixed. Male copulatory organs (Fig. 8 D,E) small 70–90 µm long, 60 µm wide and 30–40 (70) Μm high, fixed, modiolus distinct, muscular sheath weakly developed, bursal slits longitudinal, bent laterally. Subneural glands absent. Spermathecae (Figs. 6 F, 8 H,I): ectal ducts slightly shorter than body diameter, about 200–250 µm long and 12–14 µm wide, in vivo (170–210 µm, fixed), no ectal glands at the orifice. Ampullae onion-shaped without ental bulb in ampullae and without diverticula, diameter 34–47 µm, in vivo and 27–45 µm, fixed. Proximal parts of ampullae 35–42 µm long (in vivo, fixed), communication with oesophagus separate but close to each other dorsolaterally. One or two mature eggs at a time. Distribution and habitat. In Korea site 7: Dongjin-myeon, Buan-gun, Jeollabuk-do, 35 &ring; 46 ’04.6”N 126 &ring; 43 ’ 14.8 ”E, 23 m asl, agronomical fields, and site 11: Sulchon-myeon, Muju-gun, Jeollabuk-do, 35 &ring; 59 ’ 28.7 ”N 127 &ring; 50 ’ 46.8 ”E, 544 m asl, mixed forest. Differential diagnosis. Considering the shape of spermathecae with separate openings into the oesophagus, this new species is similar to 13 Fridericia species: F. c al l o s a (Eisen, 1878) sensu Schmelz (2003), F. parathalassia Schmelz, 2002, F. peregrinabunda Michaelsen, 1913, F. s i m a Welch, 1914, F. sphaerica sp. n., F. seoraksani Christensen & Dózsa-Farkas, 2012, F. b e nt i Schmelz, 2002, F. bulbosa (Rosa, 1887) sensu Rota (2015), F. rara Rota, 2015, F. meridiana Rota, 2015, F. tuberosa Rota, 1995, F. nielseni Möller, 1971, F. unisetosa Xie et al., 2000 (Schmelz 2003; Christensen & Dózsa-Farkas 2012; Rota 2015; Xie et al. 2000). The main differences between the first five species and the new species are body size (10-20 mm long), higher segment number and a larger diameter of the spermathecal ampullae. Moreover, F. ca l l o s a has type c oesophageal appendagees, F. parathalassia has only four pair nephridia preclitellarly, in F. peregrinabunda the maximum of chaetae is two per bundle, F. sphaerica sp. n. has longer spermathecal ectal ducts, and in F. si ma the maximum number of chaetae per bundle is 7–8. The smaller F. benti, F. rara and F. nielseni have a maximum of only two chaetae per bundle; moreover, F. benti has a larger spermathecal ectal gland, in F. bu l bo s a the maximum of chaetae is four and the coelomo-mucocytes type a. F. rara has only three pairs of preclitellar nephridia, F. meridiana has only 4 pairs of preclitellar nephridia, the penial (=bursal) slits are T-shaped and chylus cells occur preclitellarly; in F. nielseni the clitellum is saddle-shaped. F. tuberosa is similar to the new species by the b type coelomocytes but has only 4 pairs of preclitellar nephridia and subneural glands. In F. unisetosa the dorsal chaetal bundles are absent. Finally, F. loretensis and F. seoraksani are the most similar species to F. granulocyta, but F. loretensis has more segments (51–55), pharyngeal glands in IV are without ventral lobes and the dorsal lobes in VI have a posterior bulge projecting into VII. F. seoraksani is somewhat larger (8–15 mm), coelomocytes are type a (not type b) and the sperm funnel is cylindrical and more than two times longer than wide.

Achaeta cf. brevivasa Graefe, 1980 (Figure 13, A,B) NIBRIV0000320532, NIBRIV0000320533, slides 1084, 1085. Two adult fixed and stained specimens, collected from site 11. Segment number 20���23, length 3.1���3.5 mm, in vivo, 2.1���2.7 mm long and about 200���210 ��m wide, fixed. Pyriform glands absent, lentiform epidermal glands not detected. Clitellum and male openings in XII. Clitellum with 6 baguette-rows of hyalocytes; between rows, at the edges, granulocytes present (Fig. 13 B). Brain 65���75 ��m long (fixed) and about 1.5 times longer than wide, rounded posteriorly. Coelomocytes rounded, about 44 ��m long. One pair small secondary pharyngeal glands in VI, not well visible. Two pairs preclitellar nephridia in 6 / 7, 7/ 8. Sperm funnels small, 40���50 ��m long and 20���21 ��m wide. Spermathecae in V, about 65���75 ��m long in vivo (Fig. 13 A). The whole mounts are unfortunately not of good quality; secondary pharyngeal glands could not be seen with certainty, and lentiform epidermal glands were not detected, either. For these reasons we added a "cf." to the species name., Published as part of D��zsa-Farkas, Kl��ra, Felf��ldi, Tam��s & Hong, Yong, 2015, New enchytraeid species (Enchytraeidae, Oligochaeta) from Korea, pp. 171-197 in Zootaxa 4006 (1) on page 191, DOI: 10.11646/zootaxa.4006.1.9, http://zenodo.org/record/237087

Henlea magnaampullacea sp. n. (Figures 1 A–D, 2 A–F, 3) Type material. Holotype. NIBRIV0000320515, slide No. 1126, adult whole mount stained with borax-carmine. Type locality: Site 1: College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do, Korea, 35 º 50 '59.0"N 127 º07' 56.4 "E, 55 m asl, soil and litter layers of woodland, leg.Y. Hong, 19.05. 2014. Paratypes. NIBRIV0000320516, NIBRIV0000320517, 2 adult specimens from type locality, in 70 % ethanol. P. 103.1 – 4, slide No. 1005, 1121, 1122, 1127. Four adult whole mounts stained with borax-carmine from the type locality, 0 3.04. 2014 and 19.05. 2014. P. 103.5 – 103.10. slide No. 1098, 1119, 1120, 1128– 1130. Six specimens from site 7, Dongjin-myeon, Buan-gun, Jeollabuk-do, Korea, 35 º 46 '04.6"N 126 º 43 ' 14.8 "E, 23 m asl, soil of agronomical fields, leg. Y. Hong, 19.05. 2014. P. 103.11. Six specimens in 70 % ethanol from type locality. Further material examined. 12 and 10 specimens from sites 7 and 1, respectively. Etymology. Named after the large spermathecal ampulla (magna = large, Latin). Diagnosis. The new species can be recognized by the following combination of characters: (1) medium-sized stout worms (11–16 mm long and 600–800 Μm wide at clitellum in vivo, segments 47–58; (2) maximum 6 chaetae per bundle; (3) clitellum girdle-shaped: gland cells small in reticulate pattern dorsally and ventrally; (4) six preclitellar pairs of nephridia; (5) canals of the intestinal diverticula arranged longitudinally in VIII, dorsal vessel origin in IX; (6) coelomocytes large, rounded brownish, thickened at cell periphery; (7) seminal vesicle large; (8) sperm funnel large, cylindrical, collar wider as funnel body; (9) spermathecae with very large pear-shaped ampullae and without diverticula. Description. Holotype 16.2 mm long, 590 µm wide at VIII and 620 µm at clitellum, in vivo (11.1 mm long, 490 µm wide at VIII and 660 µm at clitellum, fixed), 52 segments. Body length of paratypes 11–16 mm, width 520–700 µm at VIII and 530–800 µm at clitellum, in vivo. Length of fixed specimens 8.7–13.5 mm, width 400–670 µm at VIII and 400–730 µm at clitellum. Segments 47–58. Chaetal formula: 2,3,4,5 – 4,5,(3,2): 2,3,4,5, 6 – 4,5,6,3. Chaetae straight, mostly unequal in size within a bundle; the largest 90–100 Μm long and 5 Μm wide, the smallest 63–70 Μm long and 4 Μm wide. Chaetae in XII absent. Head pore at 0/I, large transverse slit (Fig. 3 B). Epidermal gland cells arranged in 3–4 transverse rows per segment. Many glands also on the prostomium dorsally (Fig. 3 B). Clitellum girdle-shaped in XII– 1 / 2 XIII, gland cells small in reticulate pattern (Fig. 2 C), also between the bursal slits (Fig. 2 D). Thickness of body wall about 40–60 µm, cuticle about 1 µm, in vivo. Brain concave posteriorly, about 150 Μm long, in vivo and slightly longer than wide (Fig. 3 A). Oesophagus in VI with a pattern of transverse streaks and one pair dorso-laterally and one pair ventro-laterally lobes of oesophageal appendages. Pharyngeal glands all separate dorsally, the second and third pairs with ventral lobes (Fig. 3 E.). Chloragocytes from IV about 15–40 Μm long, in vivo (fixed 13–15 Μm). Dorsal vessel from IX, large heart-like pulsating expansion from IX to VII (Fig. 2 A), blood colourless. Intestinal diverticula forming a ring around intestine in VIII, consisting of 4 spherical diverticula, which unite proximally (Figs. 2 A,B, 3 E). Canals of the diverticula arranged longitudinally and not including large hollows; especially well visible in subadult or juvenile specimens (Fig. 3 F). Intestinal epithelium behind clitellum with tall, hyaline type of cells ventrally and laterally from XXIV–XXV to XXXI–XXXII (type 2 after Rota et al. 1998). Six pairs of preclitellar nephridia from 5 / 6 to 10 / 11 (in one case from 4 / 5–10 / 11, absent at 5 / 6), anteseptale small, efferent duct origin posteroventrally (Fig. 1 C). Coelomocytes large, rounded or ellipsoid (Fig. 3 C), with fine brown granula in the cytoplasma (coelomocyte aggregations dark brown in transmitted light), and a peripherally thickened cell border, distinct at high magnification (Fig. 3 D) (length 35– 60 Μm, in vivo, 20–30 µm, fixed). Seminal vesicle large in XI or XI–XII. Sperm funnels cylindrical, large (Figs. 1 B, 3 H–I), about 350–600 µm long and 4–6 times as long as wide, in vivo, about ¾ as long as body diameter. Funnel length in fixed specimens 230–550 µm, 2.5–4 times longer than wide. Collar wider as funnel body. Spermatozoa about 140–170 µm long, heads 40–70 µm, in vivo. Diameter of sperm ducts 12–13 µm, in vivo, 10–13 µm, fixed. Male copulatory organs (Fig. 2 D) 120–190 µm long, 100–145 µm wide and 80–110 Μm high, fixed, bursal slits H-shaped, modiolus well developed. Subneural glands absent. Spermathecae (Figs. 1 A, 2 E–F, 3 J) very prominent, large; pear-shaped ampullae without diverticula, 90–150 µm wide, up to 200 µm when full with sperm. Ectal duct about 160–300 µm long and 40–60 (80) µm wide, slightly tapering distally, canal wide (13–15 µm, in vivo), (170–260 µm long, 45–60 µm wide, diameter of canal 10–12 µm in fixed specimens). Ampullae about 250–280 µm long in vivo, merging entally and with joint opening into oesophagus in VI. At the orifice of spermathecal ducts 3–4 large glands (40–80 µm long, in vivo). 2–3 mature eggs at a time. Distribution and habitat. In Korea site 1: College of Agriculture & Life Science, Chonbuk National University, Jeonju-si, Jeollabuk-do 35 º 50 '59.0"N 127 º07' 56.4 "E, 55 m asl), woodland, sites 6 and 7, Dongjinmyeon, Buan-gun, Jeollabuk-do 35 º 46 '04.6"N 126 º 43 ' 14.8 "E, 23 m asl and 35 º 46 '04.2" 126 º 43 ' 15.6 "E, 20 m a s l, agronomical fields, and planting garden tree. Differential diagnosis. Henlea magnaampullacea sp. n. and 6 other Henlea species are characterized by intestinal diverticula with multitubular substructure in VIII, and the dorsal vessel origin in IX. Among these species, H. ventriculosa (d' Udekem, 1854), H. jutlandica Nielsen & Christensen, 1959, H. andreae Rodriguez & Giani, 1986, H. groenlandica &Ccaron;ernosvitov, 1929 augm. Christensen & Dózsa-Farkas, 2006 and H. conchifera Christensen & Dózsa-Farkas, 1999 differ from the new species in the spermathecal ampullae which are only slightly wider than the ectal ducts (Schmelz & Collado 2010; Christensen & Dózsa-Farkas 1999, 2006). H. irkutensis Burov, 1929 is much larger (60–90 segments, 23.6–55 mm) (Burov 1929). H. magnaampullacea sp. n. is most similar to Henlea ochracea (Eisen, 1978) augm. Nurminen, 1973, because both are similarly large, have up to 6 chaetae per bundle, large sperm funnels and more robust spermathecae, but the collar of sperm funnels is not so high and bent backwards in the new species, and the spermathecal ampullae are abruptly widened, about 2–3 times wider than the diameter of ectal ducts, whereas in H ochracea the ampullae are about 1.5 times wider than the ectal ducts and the duct widens gradually into the ampullae (Dózsa-Farkas, personal observation, see Christensen & Dózsa-Farkas 1999, Fig 16). Based on the phylogenetic analysis (Fig. 14), individuals from the new species were separated from other Henlea species collected in Korea, and were also distantly related to H. ochracea individuals from Alaska (identified morphologically by Dózsa-Farkas). Therefore molecular taxonomical results supported the description of a new Henlea species.

Enchytraeus buchholzi Vejdovsk��, 1879 sensu lato Recent description in Schmelz & Collado (2010)., Published as part of D��zsa-Farkas, Kl��ra, Felf��ldi, Tam��s & Hong, Yong, 2015, New enchytraeid species (Enchytraeidae, Oligochaeta) from Korea, pp. 171-197 in Zootaxa 4006 (1) on page 191, DOI: 10.11646/zootaxa.4006.1.9, http://zenodo.org/record/237087, {"references":["Schmelz, R. M. & Collado, R. (2010) A guide to European terrestrial and freshwater species of Enchytraeidae (Oligochaeta). Soil Organisms, 82 (1), 1 - 176."]}

Fridericia cusanicaformis sp. n. (Figures 6 A – C, 7) Type material. Holotype. NIBRIV0000320521, slide No. 1080, adult whole mount stained with borax carmine. Type locality: site 9: Cheontae mountain, Yeongdong-gun, Cheungcheongnam-do, Korea, 36 º06' 57.8 "N 128 º00' 30.4 "E, 201 m asl, soil and litter layers of forest, leg. Y. Hong, 15.05. 2014. Paratypes. NIBRIV0000320522, slide No. 1082, two adult whole mounts stained specimens from type locality, sampling data as for holotype. P. 104.1 – 2, slide No. 1079, 1081, sampling data as for holotype. Etymology. Named after the similarity to F. c u s a ni ca Schmelz, 2003. Diagnosis. The new species can be recognized by the following combination of characters: (1) small size (5–7 mm, in vivo), segments 29–32; (2) only one chaeta in the lateral bundles; (3) clitellum only laterally developed: hyalocytes and granulocytes arranged in transverse rows, dorsally and ventrally absent, except 1–3 rows behind bursal slits; (4) four preclitellar pairs of nephridia; (5) coelomo-mucocytes type a, lenticytes large; (6) chylus cells in X–XI; (7) seminal vesicle absent; (8) subneural glands absent; (9) sperm funnel small, cylindrical, collar narrower as funnel body; (10) spermathecae without diverticula, fused proximally, ampullae small (diameter 20–25 µm, in vivo), spermathecal ducts elongate, with small sessile ectal glands. Description. Holotype 5 mm long, 220 µm wide at VIII and 240 µm at clitellum, fixed, 30 segments. Body length of paratypes 5–7 mm, width 200 µm at VIII and 210–240 µm at clitellum, in vivo. Length of fixed specimens 3.4–5.6 mm, width 180–220 µm at VIII and 200–240 µm at clitellum. Segments 29–32. Chaetal formula: 1,(0) – 1: 2 – 2. Chaetae in preclitellar and postclitellar bundles alike, about 20–25 x 2.5 µm both ventrally and laterally. Chaetae in XII absent. Head pore at 0/I. Dorsal pores from VII. Epidermal gland cells arranged in 1–2 transverse rows per segment. Clitellum in XII– 1 / 2 XIII, only laterally developed, except for 2–3 rows posterior to the bursal slits (Fig. 7 B); dorsal gap of clitellum about 58 µm wide (Fig. 7 A); gland cells arranged in rows, hyalocytes slightly larger (diameter 17–20 x 18 Μm) than granulocytes (diameter 10–12 x 18 Μm, fixed). Thickness of body wall about 10–13 µm, cuticle about 1 µm in fixed specimens. Brain egg-shaped, about 90–100 Μm long (fixed) and 1.7 times longer than wide (Fig. 7 C). Oesophageal appendages type a, short, unbranched (Fig. 7 D). First and second pairs of pharyngeal glands united dorsally, third pair dorsally separate; in IV without and in V and VI with ventral lobes. Chloragocytes from V, about 19–23 Μm long, in vivo (fixed 5–10 Μm). Dorsal blood vessel from XIII, blood colourless. Midgut pars tumida in XIX–XXII, occupying 4 segments. Four pairs of preclitellar nephridia from 6 / 7 to 9 / 10, length ratio anteseptale: postseptale 1: 1.4–1.6, midventral origin of efferent duct preclitellarly (Fig. 7 E), postclitellarly efferent duct originating terminally (Fig. 7 F). Coelomo-mucocytes type a (length 20–30 Μm, in vivo, 13–17 µm, fixed), lenticytes large 8–13 Μm long, in vivo (5-8 µm long, fixed) (Fig. 6 B). Chylus cells between X–XI, occupying 2 segments (Fig. 7 G). Seminal vesicle small or absent. Sperm funnels cylindrical, small (Fig. 7 G), about 70–90 µm long and 1.8–2.3 times as long as wide, in vivo. Funnel length in fixed specimens 55–87 µm (Fig. 7 H). Collar narrower than funnel body. Spermatozoa about 100 µm long, heads 25–28 µm, in vivo. Diameter of sperm ducts 5 µm, fixed. Male copulatory organs (Fig. 7 B) 40–57 µm long, 30–37 µm wide and 20–32 Μm high, fixed, bursal slits were undeterminable. Subneural glands absent. Spermathecae (Fig. 7 I,J): one small, sessile ectal gland at the orifice, length about 12–17 µm, fixed. Ectal duct as long as or slightly longer than body diameter, about 195–240 µm long and 10 µm wide, in vivo (125–250 µm, fixed), canal not widened. Ampullae onion-shaped without ental bulbs in ampullae and without diverticula, diameter 20–25 µm, in vivo and fixed alike. Proximal parts of ampullae (18–20 µm long, fixed) merging and joint opening into oesophagus in V. One large mature egg at a time (in specimen No. 1079 four mature eggs). Distribution and habitat. In Korea only in site 9, Cheontae mountain, Yeongdong-gun, Cheungcheongnamdo Korea, 36 &ring;06’ 57.8 ”N 128 &ring;00’ 30.4 ”E, 201 m asl, broad-leaved forest. Differential diagnosis. The shape of the spermathecae in F. cusanicaformis sp. n. is very similar to the spermathecae of six Fridericia species: F. bulboides Nielsen & Christensen, 1959, F. bretscheri Southern, 1907, F. semisetosa Dózsa-Farkas, 1970, F. schmelzi Cech & Dózsa-Farkas, 2005, F. pretoriana Stephenson, 1930, F. losangelensis Bell, 1936; they differ all from the new species in the maximum number of ventral chaetae, four in first four species, in the case of F. pretoriana 6–8 and in F. losangelensis 4–6 (Schmelz 2003). Only F. semisetosa has 1 or 0 chaetae in the lateral bundles but differs by the number of preclitellar nephridia (5 pairs). The new species differs from these species discussed by the dorsally absent clitellum. F. cusanica Schmelz, 2003 is most similar to the new species (see etymology of F. cusanicaformis) in regard to body size, spermathecal form, the maximum number of chaetae per bundle, preclitellar location of chylus cells and oesophageal appendages type a, but F. cusanicaformis differs from F. cusanica by longer spermathecal ducts (as long as or slightly longer than body diameter), only four pairs of preclitellar nephridia, lenticytes larger (8–13 µm long) and the third pairs of pharyngeal glands in VI separate dorsally; moreover the first pharyngeal glands are without ventral lobes. In F. cusanica the spermathecal duct length is 3 / 4 of body diameter, there are five pairs of preclitellar nephridia, lenticytes are 3–5 µm long, and all pairs of pharyngeal glands with wide dorsal connection and with ventral lobes (Schmelz 2003).

Enchytraeus dichaetus Schmelz & Collado, 2010 NIBRIV0000320530, NIBRIV0000320531. Two adult specimens in 70 % ethanol. Our observations agree with Rota and Healy's (1994) original description: small species 4–7 mm long with 26–35 segments. Only two chaetae per bundle, three pairs of pharyngeal glands, all separate dorsally. Coelomocytes without refractile vesicles. Dorsal blood vessel rising in clitellar region. Sperm funnel small, the long spermathecal ectal duct covered halfway with small glands. Some specimens were athecal as observed previously by Schmelz & Collado (2010). New for the Korean fauna.