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Shimada, Daisuke, Suzuki, Atsushi C., Tsujimoto, Megumu, Imura, Satoshi, Kakui, Keiichi (2021): Two New Species of Free-living Marine Nematodes (Nematoda: Axonolaimidae and Tripyloididae) from the Coast of Antarctica. Species Diversity 26 (1): 49-63, DOI: 10.12782/specdiv.26.49, URL: http://dx.doi.org/10.12782/specdiv.26.49

Subfamily Euchromadorinae Gerlach and Riemann, 1973 Diagnosis [afler Tchesunov (2014)]. Chromadoridae. Body cuticle usually with complex heterogeneous ornamentation along the body, with or without lateral differentiation. The six outer labial and four cephalic sensilla setiform may be arranged in a single circle. Amphideal fovea transverse slit-like or oval, located posterior to the cephalic setae. Buccal cavity with large dorsal tooth, with or without denticles or smaller ventrosublateral teeth. Pharynx with or without defined terminal bulb. Gubernaculum usually with hammer- or L-shaped lateral pieces [sometimes mistakenly called as ���telamon,��� which indicates a thickened immovable plate of ventral cloacal wall in Strongylida (cf. Maggenti 1981; Tchesunov 2014)]. Precloacal supplements absent, but a precloacal differentiation of body cuticle may be present. Type genus. Euchromadora de Man, 1886. Other genera. Ten genera: 1. Actinonema Cobb, 1920 = Pareuchromadora Schuurmans Stekhoven and Adam, 1931 [synonymized by Wieser (1954)]; 2. Adeuchromadora Boucher and de Bov��e, 1971; 3. Crestanema Pastor de Ward, 1985; 4. Endeolophos Boucher, 1976; 5. Graphonema Cobb, 1898 = Protochromadora Inglis, 1969 [synonymized by Warwick and Coles (1975)]; 6. Parapinnanema Inglis, 1969 = Austranema Inglis, 1969 [synonymized by Warwick and Coles (1975)]; 7. Portmacquaria Blome, 2005 = Macquaria Blome, 2002 (junior homonym of Macquaria Cuvier in Cuvier and Valenciennes, 1830); 8. Rhips Cobb, 1920; 9. Steineridora Inglis, 1969; and 10. Trochamus Boucher and de Bov��e, 1971. Remarks. Eleven genera, including the type genus, are valid (Inglis 1969; Gerlach and Riemann 1973; Warwick and Coles 1975; Blome 2002, 2005; Tchesunov 2014). Four other genera��� Dasylaimus Cobb, 1933, Dicriconema Steiner and Hoeppli, 1926, Nygmatonchus Cobb, 1933, and Odontocricus Steiner, 1918 ���were placed in Euchromadorinae before, but recently, these are now treated as genera inquirendae (Coles 1965; Inglis 1969; Hope and Murphy 1972; Warwick and Coles 1975)., Published as part of Shimada, Daisuke, Tsujimoto, Megumu & Watanabe, Kentaro, 2019, A New Free-living Marine Nematode Species of the Genus Graphonema (Nematoda: Chromadorida: Chromadoridae) from Antarctica, pp. 61-67 in Species Diversity 24 (1) on page 62, DOI: 10.12782/specdiv.24.61, http://zenodo.org/record/4585216, {"references":["Gerlach, S. A. and Riemann, F. 1973. The Bremerhaven checklist of aquatic nematodes. A catalogue of Nematoda Adenophorea excluding the Dorylaimida. Veroffentlichungen des Instituts fur Meeresforschung in Bremerhaven, Supplement 4: 1 - 404.","Tchesunov, A. V. 2014. Order Chromadorida Chitwood, 1933. Pp. 373 - 398. In: Schmidt-Rhaesa, A. (Ed.) Handbook of Zoology. Gastrotricha, Cycloneuralia and Gnathifera. Volume 2. Nematoda. De Gruyter, Berlin and Boston.","Maggenti, A. 1981. General Nematology. Springer, New York, x + 372 pp.","Wieser, W. 1954. Reports of the Lund University Chile Expedition 1948 - 49. 17. Free-living marine nematodes. II. Chromadoroidea. Lunds Universitets Arsskriπ. Ny Foljd. Andra Avdelningen 50: 1 - 148.","Cobb, N. A. 1898. Australian free-living marine nematodes. Proceedings of the Linnean Society of New South Wales 23: 383 - 407.","Inglis, W. G. 1969. Convergence in the structure of the head and cuticle of Euchromadora species and apparently similar nematodes. Bulletin of the British Museum (Natural History). Zoology 17: 149 - 204.","Warwick, R. M. and Coles, J. W. 1975. Notes on the free-living marine genus Euchromadora de Man, 1886 and its allies, with descriptions of two new species (Chromadoridae: Nematoda). Journal of Natural History 9: 403 - 412.","Blome, D. 2005. Portmacquaria nom. nov. pro Macquaria Blome, 2002 (Nematoda: Chromadoridae). Memoirs of the Queensland Museum 50: 132.","Blome, D. 2002. Five new genera of free-living marine nematodes from sandy beaches of eastern Australia. Memoirs of the Queensland Museum 48: 29 - 43.","Coles, J. W. 1965. A critical review of the marine nematode genus Euchromadora de Man, 1886. Bulletin of the British Museum (Natural History). Zoology 12: 157 - 194.","Hope, W. D. and Murphy, D. G. 1972. A taxonomic hierarchy and checklist of the genera and higher taxa of marine nematodes. Smithsonian Contributions to Zoology 137: 1 - 101."]}

Graphonema antarcticum sp. nov. (Figs 1–4; Table 1) Material examined. Holotype: adult male (ICHUM 5867), whole mount, 68°59′55″S, 39°35′28″E, Kita-noura, off Syowa Station in Lützow-Holm Bay, Antarctica, surface of macroalgae collected by means of bait traps at 27 m depth, 16 December 2005. Paratypes: six adult males (ICHUM 5868–5872, 5876) and five adult females (ICHUM 5873–5875, 5877, 5878), whole mounts, same collection data as with holotype. Non-type: an adult male (ICHUM 5879), Au-coated SEM specimen, same collection data as with holotype. Diagnosis. Graphonema antarcticum sp. nov. is characterized by large body size (equal to or more than 2.0 mm), truncated cephalic end, presence of lateral differentiation, long spicules (80–90 µm and 1.3–1.6 abd), without capitulum, well-developed gubernaculum with L-shaped lateral pieces bending at an obtuse angle with minute denticles at distal end, and long tail in both sexes (approximately 4–6 abd in males and 6–9 abd in females). Measurements. See Table 1. Description. Males. Body (Fig. 1A) almost cylindrical, tapering toward both ends. Epicuticle coarsely annulated (Fig. 2), except at anterior and posterior body ends (Figs. 1B, 2, 4A, G). Exocuticle with heterogeneous ornamentations (cf. Gourbault and Vincx 1994): tiny punctate at anterior half of cephalic region (Figs 1B, 4A); regularly hexagonal to posterior half of cephalic region to anterior 1/3 of pharynx (Figs 1B, C, 4A, B); longitudinally elongated hexagonal from anterior 1/3 of pharynx to cloacal region (Figs 1D, E, 4C, D), becoming longer toward posterior end; regularly hexagonal in caudal region (Figs 1F, 4F), becoming smaller toward posterior end; no ornamentation at tail end (Figs 3A, 4G). Lateral differentiation (Figs 1 C–E, 4B, C) present, beginning from anterior 1/3 of pharyngeal region to cloacal region, becoming wider toward posterior end. Cephalic region (Figs 1B, G, H, 2A, B) not set-off, truncated at anterior end. Cephalic diameter 25–30% of mbd. Inner labial sensilla inconspicuous. Six outer labial setae (2–3 µm) and four cephalic setae (4–6 µm) in single circle observed in the holotype and two paratype males (ICHUM 5869 and 5871), but inconspicuous in the other individuals including SEM specimen (Fig. 2A, B). Amphids not observed. Buccal cavity (Fig. 1G) divided into two sections: cheilostome—cup-shaped, with a circle of twelve tooth-like rugae; and esophastome—conical in shape, with a large dorsal onchium, two smaller ventrosublateral onchia, and four minute ventrosublateral teeth (Fig. 1G, H). Denticles absent. Pharynx (Fig. 1A, G) anteriorly surrounding esophastome, without posterior terminal bulb. Excretory pore and nerve ring indistinct. Ventral gland cell (Fig. 1A) located posterior to base of pharynx, posterior edge of gland at 1.5 times pharyngeal length from anterior body end. Testis (Fig. 1A) single, outstretched, beginning at anterior 20–25% of body length, located on right-hand side of intestine, posterior junction of vas deferens inconspicuous (complete testis observed only in the holotype and paratype ICHUM 5869, probably because of damage caused by freezing). Spicules (Fig. 3B, C) equal, arcuate, without capitulum, gradually tapering distally and 1.3–1.6 abd or 30–40% of tail length. Gubernaculum (Fig. 3C) well-developed: dorsal piece thin, almost straight and parallel to spicules; lateral pieces paired, L-shaped and bending at an obtuse angle, with one or two minute denticles at distal end; whole length (from proximal end of dorsal piece to distal end of lateral piece) 50–55% of spicule length. Precloacal supplement or cuticular elevation absent. A longitudinal row of cuticular wrinkles (Figs 3B, 4E) present at both subventral sides of precloacal region in all males, however it possibly artefact of preservation in ethanol and/or freezing. One or two short ventral setae just anterior to cloaca either present or absent. Tail (Fig. 3B) conico-cylindrical, 3.9–6.0 abd long, without ventral cuticular elevation. Three caudal glands just anterior to cloaca. Distinct spinneret at tip of tail. Females. Body (Fig. 3D) similar to males but thicker (mbd approximately 100–120 µm). Cephalic diameter 20– 25% of mbd. In one specimen (ICHUM 5877), ventral gland cell reaches 1.9 times pharyngeal length from anterior body end. Female reproductive system didelphic and amphidelphic. Ovaries opposed and reflexed: anterior ovary beginning at 15–30% of body length, located on right-hand side of intestine; posterior ovary ending at 70% of body length, located on leπ-hand side of intestine. Eggs oval, 3–18 in uteri, 30–60 µm in diameter. Vulva situated slightly anterior to middle of body. Tail 6.1–8.4 abd long, longer and thinner than in males. Three caudal glands situated in anal region, one or two of them located preanally, and the others located postanally. Etymology. The specific name antarcticum (Antarctic) is a Latin adjective taken from the type locality. Remarks. Graphonema antarcticum sp. nov. is most similar to G. metuliferum described from Japan in respect of the longer spicules (approximately 1.5 abd), the shape of the gubernaculum (whole length approximately 1/2 of spicule length, and with L-shaped lateral pieces bending at an obtuse angle and equipped with minute denticles at the distal end), and tail length in both sexes (approximately 4–6 abd in males and 6–9 abd in females). However, G. antarcticum sp. nov. differs from G. metuliferum by larger body size (L=2.0– 2.5 mm in males, 2.2–2.7 mm in females of G. antarcticum sp. nov. vs. 1.0– 1.4 mm in males, 1.2–1.4 mm in females of G. metuliferum) and the presence of the lateral differentiation (absent in G. metuliferum) (Fig. 4 H–J). The presence or absence of lateral differentiation is a good diagnostic character used to distinguish species or genera in Chromadoridae (cf. Tchesunov 2014). The genus Graphonema contains five species reported to have lateral differentiation, viz., G. arcticum, G. northumbriae G. parafricanum, G. scampae, and G. antarcticum sp. nov., and only one species, G. metuliferum, reported to have no lateral differentiation (Filipjev 1946; Gerlach 1958; Coles 1965; Warwick and Coles 1975; Kito 1981). It is unknown that lateral differentiation is present or absent in the other four known species. In addition, following minor differences are found from the original description by Kito (1981) and our observation of the type series of G. metuliferum, but these may not be enough for the diagnostic characters: amphideal fovea (indistinct in G. antarcticum sp. nov. vs. distinct in G. metuliferum), ventral gland cell (rounded in G. antarcticum sp. nov. vs. elongated in G. metuliferum), and longitudinal rows of cuticular wrinkles in precloacal region (present in G. antarcticum sp. nov. vs. absent in G. metuliferum).The distinctions between the new species and all known congeners are shown in the following key.

Shimada, Daisuke, Tsujimoto, Megumu, Watanabe, Kentaro (2019): A New Free-living Marine Nematode Species of the Genus Graphonema (Nematoda: Chromadorida: Chromadoridae) from Antarctica. Species Diversity 24 (1): 61-67, DOI: 10.12782/specdiv.24.61, URL: http://dx.doi.org/10.12782/specdiv.24.61

Genus Graphonema Cobb, 1898 Protochromadora Inglis, 1969: 177. Diagnosis [modified from Inglis (1969), Warwick and Coles (1975) and Tchesunov (2014)]. Euchromadorinae. Body cuticle with complex heterogeneous ornamentation. Lateral differentiation either present or absent. Amphideal fovea either transverse slit-like without a double contour, or not observed. Buccal cavity with a hollow dorsal onchium and two lateral or ventrosublateral onchia, without rows of denticles. Pharynx without posterior terminal bulb. Spicules not jointed. Gubernaculum containing a dorsal piece and a pair of hammer- or L-shaped lateral pieces. Precloacal supplement absent. Pre- and postcloacal cuticular elevation also absent. Type species. Graphonema vulgare Cobb, 1898 (originally spelled G. vulgaris). Other species. Nine species: 1. G. amokurae (Ditlevsen, 1921) Inglis, 1969 = Spilophora amokurae Ditlevsen, 1921 = Euchromadora amokurae Allg��n, 1929; 2. G. arcticum (Filipjev, 1946) Warwick and Coles, 1975 = Euchromadora arctica Filipjev, 1946; 3. G. georgei Inglis, 1969; 4. G. mediterraneum (Allg��n, 1942) Warwick and Coles, 1975 = Euchromadora mediterranea Allg��n, 1942 = Protochromadora mediterranea Inglis, 1969; 5. G. metuliferum Kito, 1981; 6. G. northumbriae Warwick and Coles, 1975; 7. G. parafricanum (Gerlach, 1958) Warwick and Coles, 1975 = Euchromadora parafricana Gerlach, 1958 = Protochromadora parafricana Inglis, 1969; 8. G. scampae (Coles, 1965) Warwick and Coles, 1975 = Euchromadora scampae Coles, 1965 = Protochromadora scampae Inglis, 1969; and 9. G. antarcticum sp. nov. Remarks. Ten species, including the type species, are valid (Cobb 1898; Wieser 1954, 1959a; Inglis 1969; Gerlach and Riemann 1973; Warwick and Coles 1975; Kito 1981). Graphonema achaeta Platonova, 1971 should be transferred to Endeolophos because of the absence of the lateral pieces of gubernaculum (Platonova 1971). Two specific names, G. pachyderma nom. nud. by Cobb (1898), and G. biseriale nom. nud. by Wieser (1959b; originally spelled G. biserialis) are unavailable (Gerlach and Riemann 1973), because they were published without any description, definition, or bibliographic reference., Published as part of Shimada, Daisuke, Tsujimoto, Megumu & Watanabe, Kentaro, 2019, A New Free-living Marine Nematode Species of the Genus Graphonema (Nematoda: Chromadorida: Chromadoridae) from Antarctica, pp. 61-67 in Species Diversity 24 (1) on page 62, DOI: 10.12782/specdiv.24.61, http://zenodo.org/record/4585216, {"references":["Cobb, N. A. 1898. Australian free-living marine nematodes. Proceedings of the Linnean Society of New South Wales 23: 383 - 407.","Inglis, W. G. 1969. Convergence in the structure of the head and cuticle of Euchromadora species and apparently similar nematodes. Bulletin of the British Museum (Natural History). Zoology 17: 149 - 204.","Warwick, R. M. and Coles, J. W. 1975. Notes on the free-living marine genus Euchromadora de Man, 1886 and its allies, with descriptions of two new species (Chromadoridae: Nematoda). Journal of Natural History 9: 403 - 412.","Tchesunov, A. V. 2014. Order Chromadorida Chitwood, 1933. Pp. 373 - 398. In: Schmidt-Rhaesa, A. (Ed.) Handbook of Zoology. Gastrotricha, Cycloneuralia and Gnathifera. Volume 2. Nematoda. De Gruyter, Berlin and Boston.","Filipjev, I. N. 1946. Nematodes libres du bassin polaire. Trudy dreifuiushchaia ekspeditsiia Glavsevmorputi na ledokol'nom parokhode \" G. Sedov \" 1937 - 1940 3: 158 - 184.","Kito, K. 1981. Studies on the free-living marine nematodes from Hokkaido, IV. Journal of the Faculty of Science, Hokkaido University. Series VI, Zoology 22: 250 - 278.","Gerlach, S. A. 1958. Freilebende Nematoden von den Korallenriffen des Roten Meeres. Kieler Meeresforschungen 14: 241 - 246.","Coles, J. W. 1965. A critical review of the marine nematode genus Euchromadora de Man, 1886. Bulletin of the British Museum (Natural History). Zoology 12: 157 - 194.","Wieser, W. 1954. Reports of the Lund University Chile Expedition 1948 - 49. 17. Free-living marine nematodes. II. Chromadoroidea. Lunds Universitets Arsskriπ. Ny Foljd. Andra Avdelningen 50: 1 - 148.","Wieser, W. 1959 a. Free-living Nematodes and Other Small Invertebrates of Puget Sound Beaches. University of Washington Press, Seattle, vii + 179 pp.","Gerlach, S. A. and Riemann, F. 1973. The Bremerhaven checklist of aquatic nematodes. A catalogue of Nematoda Adenophorea excluding the Dorylaimida. Veroffentlichungen des Instituts fur Meeresforschung in Bremerhaven, Supplement 4: 1 - 404.","Platonova, T. A. 1971. Free-living marine nematodes from the Possjet Bay of the Sea of Japan. Pp. 72 - 108. In: Academy of Sciences of the USSR, Zoological Institute (Ed.) Fauna and Flora of the Possjet Bay of the Sea of Japan: Hydrobiological Investigations by Means of Diving Method. Explorations of the Fauna of the Seas 8 (16). The Academy of Sciences of the USSR, Leningrad. [In Russian]","Wieser, W. 1959 b. A note on subterranean nematodes from Chesapeake Bay, Md. Limnology and Oceanography 4: 225 - 227."]}

Graphonema antarcticum sp. nov. (Figs 1���4; Table 1) Material examined. Holotype: adult male (ICHUM 5867), whole mount, 68��59���55���S, 39��35���28���E, Kita-noura, off Syowa Station in L��tzow-Holm Bay, Antarctica, surface of macroalgae collected by means of bait traps at 27 m depth, 16 December 2005. Paratypes: six adult males (ICHUM 5868���5872, 5876) and five adult females (ICHUM 5873���5875, 5877, 5878), whole mounts, same collection data as with holotype. Non-type: an adult male (ICHUM 5879), Au-coated SEM specimen, same collection data as with holotype. Diagnosis. Graphonema antarcticum sp. nov. is characterized by large body size (equal to or more than 2.0 mm), truncated cephalic end, presence of lateral differentiation, long spicules (80���90 ��m and 1.3���1.6 abd), without capitulum, well-developed gubernaculum with L-shaped lateral pieces bending at an obtuse angle with minute denticles at distal end, and long tail in both sexes (approximately 4���6 abd in males and 6���9 abd in females). Measurements. See Table 1. Description. Males. Body (Fig. 1A) almost cylindrical, tapering toward both ends. Epicuticle coarsely annulated (Fig. 2), except at anterior and posterior body ends (Figs. 1B, 2, 4A, G). Exocuticle with heterogeneous ornamentations (cf. Gourbault and Vincx 1994): tiny punctate at anterior half of cephalic region (Figs 1B, 4A); regularly hexagonal to posterior half of cephalic region to anterior 1/3 of pharynx (Figs 1B, C, 4A, B); longitudinally elongated hexagonal from anterior 1/3 of pharynx to cloacal region (Figs 1D, E, 4C, D), becoming longer toward posterior end; regularly hexagonal in caudal region (Figs 1F, 4F), becoming smaller toward posterior end; no ornamentation at tail end (Figs 3A, 4G). Lateral differentiation (Figs 1 C���E, 4B, C) present, beginning from anterior 1/3 of pharyngeal region to cloacal region, becoming wider toward posterior end. Cephalic region (Figs 1B, G, H, 2A, B) not set-off, truncated at anterior end. Cephalic diameter 25���30% of mbd. Inner labial sensilla inconspicuous. Six outer labial setae (2���3 ��m) and four cephalic setae (4���6 ��m) in single circle observed in the holotype and two paratype males (ICHUM 5869 and 5871), but inconspicuous in the other individuals including SEM specimen (Fig. 2A, B). Amphids not observed. Buccal cavity (Fig. 1G) divided into two sections: cheilostome���cup-shaped, with a circle of twelve tooth-like rugae; and esophastome���conical in shape, with a large dorsal onchium, two smaller ventrosublateral onchia, and four minute ventrosublateral teeth (Fig. 1G, H). Denticles absent. Pharynx (Fig. 1A, G) anteriorly surrounding esophastome, without posterior terminal bulb. Excretory pore and nerve ring indistinct. Ventral gland cell (Fig. 1A) located posterior to base of pharynx, posterior edge of gland at 1.5 times pharyngeal length from anterior body end. Testis (Fig. 1A) single, outstretched, beginning at anterior 20���25% of body length, located on right-hand side of intestine, posterior junction of vas deferens inconspicuous (complete testis observed only in the holotype and paratype ICHUM 5869, probably because of damage caused by freezing). Spicules (Fig. 3B, C) equal, arcuate, without capitulum, gradually tapering distally and 1.3���1.6 abd or 30���40% of tail length. Gubernaculum (Fig. 3C) well-developed: dorsal piece thin, almost straight and parallel to spicules; lateral pieces paired, L-shaped and bending at an obtuse angle, with one or two minute denticles at distal end; whole length (from proximal end of dorsal piece to distal end of lateral piece) 50���55% of spicule length. Precloacal supplement or cuticular elevation absent. A longitudinal row of cuticular wrinkles (Figs 3B, 4E) present at both subventral sides of precloacal region in all males, however it possibly artefact of preservation in ethanol and/or freezing. One or two short ventral setae just anterior to cloaca either present or absent. Tail (Fig. 3B) conico-cylindrical, 3.9���6.0 abd long, without ventral cuticular elevation. Three caudal glands just anterior to cloaca. Distinct spinneret at tip of tail. Females. Body (Fig. 3D) similar to males but thicker (mbd approximately 100���120 ��m). Cephalic diameter 20��� 25% of mbd. In one specimen (ICHUM 5877), ventral gland cell reaches 1.9 times pharyngeal length from anterior body end. Female reproductive system didelphic and amphidelphic. Ovaries opposed and reflexed: anterior ovary beginning at 15���30% of body length, located on right-hand side of intestine; posterior ovary ending at 70% of body length, located on le��-hand side of intestine. Eggs oval, 3���18 in uteri, 30���60 ��m in diameter. Vulva situated slightly anterior to middle of body. Tail 6.1���8.4 abd long, longer and thinner than in males. Three caudal glands situated in anal region, one or two of them located preanally, and the others located postanally. Etymology. The specific name antarcticum (Antarctic) is a Latin adjective taken from the type locality. Remarks. Graphonema antarcticum sp. nov. is most similar to G. metuliferum described from Japan in respect of the longer spicules (approximately 1.5 abd), the shape of the gubernaculum (whole length approximately 1/2 of spicule length, and with L-shaped lateral pieces bending at an obtuse angle and equipped with minute denticles at the distal end), and tail length in both sexes (approximately 4���6 abd in males and 6���9 abd in females). However, G. antarcticum sp. nov. differs from G. metuliferum by larger body size (L=2.0��� 2.5 mm in males, 2.2���2.7 mm in females of G. antarcticum sp. nov. vs. 1.0��� 1.4 mm in males, 1.2���1.4 mm in females of G. metuliferum) and the presence of the lateral differentiation (absent in G. metuliferum) (Fig. 4 H���J). The presence or absence of lateral differentiation is a good diagnostic character used to distinguish species or genera in Chromadoridae (cf. Tchesunov 2014). The genus Graphonema contains five species reported to have lateral differentiation, viz., G. arcticum, G. northumbriae G. parafricanum, G. scampae, and G. antarcticum sp. nov., and only one species, G. metuliferum, reported to have no lateral differentiation (Filipjev 1946; Gerlach 1958; Coles 1965; Warwick and Coles 1975; Kito 1981). It is unknown that lateral differentiation is present or absent in the other four known species. In addition, following minor differences are found from the original description by Kito (1981) and our observation of the type series of G. metuliferum, but these may not be enough for the diagnostic characters: amphideal fovea (indistinct in G. antarcticum sp. nov. vs. distinct in G. metuliferum), ventral gland cell (rounded in G. antarcticum sp. nov. vs. elongated in G. metuliferum), and longitudinal rows of cuticular wrinkles in precloacal region (present in G. antarcticum sp. nov. vs. absent in G. metuliferum).The distinctions between the new species and all known congeners are shown in the following key., Published as part of Shimada, Daisuke, Tsujimoto, Megumu & Watanabe, Kentaro, 2019, A New Free-living Marine Nematode Species of the Genus Graphonema (Nematoda: Chromadorida: Chromadoridae) from Antarctica, pp. 61-67 in Species Diversity 24 (1) on pages 63-66, DOI: 10.12782/specdiv.24.61, http://zenodo.org/record/4585216, {"references":["Gourbault, N. and Vincx, M. 1994. New species of Parapinnanema (Nematoda: Chromadoridae) are described, with a discussion of the genus. Australian Journal of Marine and Freshwater Research 45: 141 - 159.","Kito, K. 1981. Studies on the free-living marine nematodes from Hokkaido, IV. Journal of the Faculty of Science, Hokkaido University. Series VI, Zoology 22: 250 - 278.","Tchesunov, A. V. 2014. Order Chromadorida Chitwood, 1933. Pp. 373 - 398. In: Schmidt-Rhaesa, A. (Ed.) Handbook of Zoology. Gastrotricha, Cycloneuralia and Gnathifera. Volume 2. Nematoda. De Gruyter, Berlin and Boston.","Filipjev, I. N. 1946. Nematodes libres du bassin polaire. Trudy dreifuiushchaia ekspeditsiia Glavsevmorputi na ledokol'nom parokhode \" G. Sedov \" 1937 - 1940 3: 158 - 184.","Gerlach, S. A. 1958. Freilebende Nematoden von den Korallenriffen des Roten Meeres. Kieler Meeresforschungen 14: 241 - 246.","Coles, J. W. 1965. A critical review of the marine nematode genus Euchromadora de Man, 1886. Bulletin of the British Museum (Natural History). Zoology 12: 157 - 194.","Warwick, R. M. and Coles, J. W. 1975. Notes on the free-living marine genus Euchromadora de Man, 1886 and its allies, with descriptions of two new species (Chromadoridae: Nematoda). Journal of Natural History 9: 403 - 412."]}

Genus Flabegraviera Salazar-Vallejo, 2012 (New Japanese name: Kibukure-habouki-zoku), Published as part of Jimi, Naoto, Tsujimoto, Megumu, Watanabe, Kentaro, Kakui, Keiichi & Kajihara, Hiroshi, 2017, A new species and the shallowest record of Flabegraviera Salazar-Vallejo, 2012 (Annelida: Flabelligeridae) from Antarctica, pp. 477-485 in Zootaxa 4221 (4) on page 478, DOI: 10.11646/zootaxa.4221.4.4, http://zenodo.org/record/252505, {"references":["Salazar-Vallejo, S. I. (2012) Revision of Flabelligera Sars, 1829 (Polychaeta: Flabelligeridae). Zootaxa, 3203, 1 - 64."]}

Flabegraviera fujiae sp. nov. (New Japanese name: Fuji-kibukure-habouki) (Figs 1���2) Type material. Holotype. NSMT-Pol-H-609. Complete (some chaetae broken, dissected), sex undetermined, nonreproductive-adult, Nishinoura (69��00.4��S, 39��34.5��E), 9 m depth, sandy mud, 16 Jan., 1981. Description. Holotype (NSMT-Pol-H-609) 9.4 cm long, 1.8 cm wide. Body fusiform, covered by very thick tunic (Fig. 1 A). Tunic transparent, gel-like, covering whole body except cephalic cage (partially eroded); sediment grains attached dorsally, ventrally, and laterally (size in long axis ~40 ��m), not immersed in tunic. Body papillated; papillae long, clavate, forming sheath covering chaetae, mostly eroded. Lobe on dorsum of chaetiger 1 absent. Dorsal and ventral surface irregular. Prostomium low cone. Branchiae 6���8 rows, about 110 filaments per side, 3���5 mm long, decreasing in size ventrally, black in ethanol. Branchial plate crescent-like, bisected by well-developed caruncle (Fig. 1 B). Palps long (6 mm), cylindrical, pink in ethanol. Four black eyes present. Lateral and dorsal lips well developed; ventral lip reduced. Nephridial lobes present. Chaetigers 33 in number; chaetiger 1 comprising cephalic cage. Cephalic cage 1.6 cm long, exposed whole, about 1/5 body length (9/10 body width), comprising 39 notochaetae and 24 neurochaetae per side. Chaetal transition from cephalic cage to body abrupt. Parapodia well developed, completely covered by tunic, notopodia and neuropodia widely separated. Gonopodial lobe absent. Chaetal bundles arranged into a straight series not like F. mundata. Notochaetae of two types: 1) multiarticulated, 1.2���3.4 cm long, 5���7 per fascicle (Fig. 2 A); and 2) not multiarticulated, 3 mm long, 8���10 per fascicle (Fig. 2 B). Neurochaetae multiarticulated capillaries in chaetiger 1. Neurohooks in chaetigers 2���33 (Fig. 2 C, D), 3���5 per fascicle, anchylosed, 0.7���0.9 cm long, pale orange, covered by a cylindrical shaft; crest bending region anchylosed. Multiarticulated neurohooks absent. Posterior end exposed, truncate; last two segments achaetous; pygidium simple; no anal cirri; anus without pigment (Fig. 1 C). Etymology. The species is named after the Japanese icebreaker Fuji, utilized for the research operation during which KW collected the holotype. The derivation is made after the vessel���s name taken as a feminine proper name. The new specific name is thus a noun in the genitive case. The Japanese name literally means ���Fuji���s thickly dressed flabelligerid���, derived from kibukure (thick-dressed) and haboukigokai (flabelligerid polychaete). Remarks. Morphologically, Flabegraviera fujiae sp. nov. resembles Flabegraviera profunda Salazar-Vallejo, 2012 because in both species the notochaetal arrangement follows a straight-line, the neurohooks are anchylosed, and the tunic carries sediment grains. However, F. fujiae can be discriminated from F. profunda by the relative size and exposure of the cephalic cage, which is exposed almost entirely in F. fujiae, whereas it is covered by the tunic in F. profunda. In addition, the cephalic cage is about 1/5 body length in F. fujiae, compared to about 1/ 10 in F. profunda. An additional difference is that F. fujiae has eyes. Our specimen was collected from a depth of 9 m, that is markedly shallower than the previous records for F. profunda, collected in sediments at 330���450 m water depth (Salazar-Vallejo 2012)., Published as part of Jimi, Naoto, Tsujimoto, Megumu, Watanabe, Kentaro, Kakui, Keiichi & Kajihara, Hiroshi, 2017, A new species and the shallowest record of Flabegraviera Salazar-Vallejo, 2012 (Annelida: Flabelligeridae) from Antarctica, pp. 477-485 in Zootaxa 4221 (4) on pages 478-481, DOI: 10.11646/zootaxa.4221.4.4, http://zenodo.org/record/252505, {"references":["Salazar-Vallejo, S. I. (2012) Revision of Flabelligera Sars, 1829 (Polychaeta: Flabelligeridae). Zootaxa, 3203, 1 - 64."]}

Flabegraviera fujiae sp. nov. (New Japanese name: Fuji-kibukure-habouki) (Figs 1–2) Type material. Holotype. NSMT-Pol-H-609. Complete (some chaetae broken, dissected), sex undetermined, nonreproductive-adult, Nishinoura (69°00.4´S, 39°34.5´E), 9 m depth, sandy mud, 16 Jan., 1981. Description. Holotype (NSMT-Pol-H-609) 9.4 cm long, 1.8 cm wide. Body fusiform, covered by very thick tunic (Fig. 1 A). Tunic transparent, gel-like, covering whole body except cephalic cage (partially eroded); sediment grains attached dorsally, ventrally, and laterally (size in long axis ~40 µm), not immersed in tunic. Body papillated; papillae long, clavate, forming sheath covering chaetae, mostly eroded. Lobe on dorsum of chaetiger 1 absent. Dorsal and ventral surface irregular. Prostomium low cone. Branchiae 6–8 rows, about 110 filaments per side, 3–5 mm long, decreasing in size ventrally, black in ethanol. Branchial plate crescent-like, bisected by well-developed caruncle (Fig. 1 B). Palps long (6 mm), cylindrical, pink in ethanol. Four black eyes present. Lateral and dorsal lips well developed; ventral lip reduced. Nephridial lobes present. Chaetigers 33 in number; chaetiger 1 comprising cephalic cage. Cephalic cage 1.6 cm long, exposed whole, about 1/5 body length (9/10 body width), comprising 39 notochaetae and 24 neurochaetae per side. Chaetal transition from cephalic cage to body abrupt. Parapodia well developed, completely covered by tunic, notopodia and neuropodia widely separated. Gonopodial lobe absent. Chaetal bundles arranged into a straight series not like F. mundata. Notochaetae of two types: 1) multiarticulated, 1.2–3.4 cm long, 5–7 per fascicle (Fig. 2 A); and 2) not multiarticulated, 3 mm long, 8–10 per fascicle (Fig. 2 B). Neurochaetae multiarticulated capillaries in chaetiger 1. Neurohooks in chaetigers 2–33 (Fig. 2 C, D), 3–5 per fascicle, anchylosed, 0.7–0.9 cm long, pale orange, covered by a cylindrical shaft; crest bending region anchylosed. Multiarticulated neurohooks absent. Posterior end exposed, truncate; last two segments achaetous; pygidium simple; no anal cirri; anus without pigment (Fig. 1 C). Etymology. The species is named after the Japanese icebreaker Fuji, utilized for the research operation during which KW collected the holotype. The derivation is made after the vessel’s name taken as a feminine proper name. The new specific name is thus a noun in the genitive case. The Japanese name literally means ‘Fuji’s thickly dressed flabelligerid’, derived from kibukure (thick-dressed) and haboukigokai (flabelligerid polychaete). Remarks. Morphologically, Flabegraviera fujiae sp. nov. resembles Flabegraviera profunda Salazar-Vallejo, 2012 because in both species the notochaetal arrangement follows a straight-line, the neurohooks are anchylosed, and the tunic carries sediment grains. However, F. fujiae can be discriminated from F. profunda by the relative size and exposure of the cephalic cage, which is exposed almost entirely in F. fujiae, whereas it is covered by the tunic in F. profunda. In addition, the cephalic cage is about 1/5 body length in F. fujiae, compared to about 1/ 10 in F. profunda. An additional difference is that F. fujiae has eyes. Our specimen was collected from a depth of 9 m, that is markedly shallower than the previous records for F. profunda, collected in sediments at 330–450 m water depth (Salazar-Vallejo 2012).

Flabegraviera mundata (Gravier, 1906) Flabelligera mundata Gravier, 1906, 537���538; Gravier 1907, 37���39, Pl. 4, Figs 31���32, Text figs 22���23; Gravier 1911, 110��� 112, Pl. 8, Fig. 87; Benham 1921, 108���109; Monro 1939, 130; Hartman 1952, 233; Hartman 1953, 50; Hartman 1966, 37��� 39, Pl. 11, Figs 1���4; Hartman 1967, 124; Hartman 1978, 170; Rozbaczylo 1985, 159; Hartmann-Schr��der & Rosenfeldt 1989, 72; Knox & Cameron 1998, 72, Figs 137���139. Flabegraviera mundata: Salazar-Vallejo 2012, 43���44, Fig. 18. (New Japanese name: Kibukure-habouki) (Figs 3���4) Material examined. Nontype specimen. NSMT-Pol- 113161. Complete (some chaetae broken, dissected), sex undetermined, non-reproductive adult, Nishinoura (69��00.4��S, 39��34.5��E), 8 m depth, sandy mud, 16 Jan., 1981. Description. Nontype (NSMT-Pol- 113161) 6.0 cm long, 1.1 cm wide, fusiform, covered by very thick tunic (Fig. 3 A). Tunic transparent, gel-like, covering whole body and posterior portion of cephalic cage; sediment grains not attached. Body papillated; papillae long, clavate, forming sheath around base of chaetae. Lobe on dorsum of chaetiger 1 absent. Dorsal and ventral surface irregular. Prostomium low cone. Branchiae 5���7 rows, about 120 filaments per side, 3 mm long, decreasing in size ventrally, colorless in ethanol. Branchial plate crescent-like, bisected by well-developed caruncle. Palps long (8 mm), cylindrical, grooved, pink in ethanol. Four black eyes present. Lateral and dorsal lips well developed, ventral lip reduced. Nephridial lobes present. Chaetigers 30 in number; chaetiger 1 comprising cephalic cage. Cephalic cage 0.7 cm long, exposed for anterior 0.2���0.3 cm (Fig. 3 B), about 1/10 body length (6/10 body width), comprising 36 notochaetae and 30 neurochaetae per side. Chaetal transition from cephalic cage to body abrupt. Parapodia poorly developed, completely covered by tunic; notopodia and neuropodia widely separated. Gonopodial lobe absent. Chaetal arrangement from chaetiger 1 (using ���u��� for upper, ���m��� for middle, and ���l��� for lower (cf. Salazar- Vallejo 2012)): ululumluml.... Notochaetae of single type, multiarticulated, 1.1���2.6 cm long, sickle-like, 4���6 per fascicle. Neurohooks in chaetigers 2���30 (Fig. 4 A), 3 per fascicle, multiarticulated, 0.6���1.1 cm long, dark orange, covered by cylindrical shaft; handle anchylosed basally and distally, articulated in between, with 17 articles, progressively longer towards distal end (Fig. 4 B); crest distinct, width: length = 1: 7. Posterior end not exposed; pygidium simple; no anal cirri; anus without pigment. Remarks. The syntype specimens of Flabegraviera mundata (Gravier, 1906) were collected from 40 m and other specimens from a 20���385 m depth range (Salazar-Vallejo 2012). Our specimen was collected from 8 m depth, making it the shallowest record of the species. The finding of this species and also F. fujiae sp. nov. in shallow water means good opportunities for future research on adaptation of annelids to extreme environments, since the locality can be sampled using SCUBA., Published as part of Jimi, Naoto, Tsujimoto, Megumu, Watanabe, Kentaro, Kakui, Keiichi & Kajihara, Hiroshi, 2017, A new species and the shallowest record of Flabegraviera Salazar-Vallejo, 2012 (Annelida: Flabelligeridae) from Antarctica, pp. 477-485 in Zootaxa 4221 (4) on page 481, DOI: 10.11646/zootaxa.4221.4.4, http://zenodo.org/record/252505, {"references":["Gravier, C. (1906) Sur les annelides polychetes recueillies par l'Expedition Antarctique Francaise (Aphroditiens, Amphinomiens, Flabelligeriens, Maldaniens, Ampharetiens). Bulletin du Museum d'Histoire Naturelle, Paris, 12, 535 - 540.","Gravier, C. (1907) Annelides polychetes. In: Joubin, L. (Ed.), Expedition Antarctique Francaise (1903 - 1905) Commandee par le Dr. Jean Charcot. Masson et Cie, Paris, pp. 1 - 75.","Gravier, C. (1911) Annelides polychetes. In: Joubin, L. (Ed.), Deuxieme Expedition Antarctique Francaise (1908 - 1910) Commandee par le Dr. Jean Charcot. Masson et Cie, Paris, pp. 1 - 165.","Benham, W. (1921) Polychaeta. Australasian Antarctic Expedition 1911 - 14 under the leadership of Sir Douglas Mawson. Scientific Reports of the Australasian Antarctic Expedition 1911 - 1914, Series C, Zoology and Botany, 3, 185 - 201.","Monro, C. C. A. (1939) Polychaeta. Reports of the British Antarctic Research Expedition 1929 - 1931, Series B, 4 (4), 87 - 156.","Hartman, O. (1952) The marine annelids of the United States Navy Antartic Expedition, 1947 - 48. Journal of the Washington Academy of Sciences, 42, 231 - 237.","Hartman, O. (1953) Non-pelagic Polychaeta of the Swedish Antarctic Expedition 1901 - 1903. Further Zoological Result on the Swedish Antarctic Expedition 1901 - 1903, under the Direction of Dr. Otto Nordenskjold, 4 (11), 1 - 83.","Hartman, O. (1966) Polychaeta Myzostomidae and Sedentaria of Antartica. Antartic Research Series, 7, 1 - 155. https: // doi. org / 10.1029 / AR 007","Hartman, O. (1967) Polychaetous annelids collected by the USNS Eltanin and Staten Island cruises, chiefly from Antarctic Seas. Allan Hancock Monographs in Marine Biology, 2, 1 - 387.","Hartman, O. (1978) Polychaeta from the Weddell Sea Quadrant, Antarctica. Antarctic Research Series, 26, 125 - 222. https: // doi. org / 10.1029 / AR 026 p 0125","Rozbaczylo, N. (1985) Los anelidos poliquetos de Chile: Indice sinonimico y distribucion geografica de especies. Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Monografias Biologicas, 3, 1 - 284.","Hartmann-Schroder, G. & Rosenfeldt, P. (1989) Die Polychaeten der \" Polarstern \" - Reise ANT III / 2 in die Antarktis 1984. Teil 2: Cirratulidae bis Serpulidae. Mitteilungen aus dem Hamburgischen Zoologischen Museum und Institut, 86, 65 - 106.","Knox, G. A. & Cameron, D. B. (1998) The marine fauna of the Ross Sea: Polychaeta. National Institute of Water and Atmospheric Research, Biodiversity Memoir, 108, 1 - 125.","Salazar-Vallejo, S. I. (2012) Revision of Flabelligera Sars, 1829 (Polychaeta: Flabelligeridae). Zootaxa, 3203, 1 - 64."]}

Shimada, Daisuke, Suzuki, Atsushi C., Tsujimoto, Megumu, Imura, Satoshi, Kakui, Keiichi (2017): Oncholaimus langhovdensis sp. nov. (Nematoda: Enoplea: Oncholaimida), a New Species of Free-living Marine Nematode from Langhovde, Dronning Maud Land, East Antarctica. Species Diversity 22: 151-159, DOI: 10.12782/sd.22_151