Search

A remarkable new genus and species of scale worm (Annelida: Polynoidae) was found on the bottom sediments of an anchialine cave on the island of Mallorca (Balearic Islands, western Mediterranean). Specimens reach up to 2 cm long, lack eyes and body pigmentation except for a few scattered minute speckles and show enlarged parapodia and sensorial appendages. A red brain is visible through the translucent tegument. Morphological features resemble those of Eulagiscinae, currently comprising eight species in three genera. Phylogenetic analyses of mitochondrial and nuclear DNA sequences are not conclusive on the position of the new taxon but affinity to Eulagiscinae is not ruled out, particularly when taxa with missing data or non-homologous insertion sites are excluded from the analyses. Pollentia perezi gen. & sp. nov. is characterized by a unique set of morphological features: 13 pairs of dorsal elytra; a single type of notochaetae (stout, with spinous rows and pointed tip); and two types of neurochaetae (superior flattened, spinous with tridentate tip; inferior shorter and thinner, lanceolate and pectinate). Some characteristics, such as the long parapodial appendages and swimming habits, are shared with other cave scale worms. However, the new taxon is not closely related to the other two known cave-dwelling polynoids., M.C. was funded by the Ramón y Cajal programme (RYC-2016-20799) funded by Spanish Ministerio de Economía, Industria y Competitividad (MINECO), Agencia Estatal de Investigación, Govern de les Illes Balears and the European Social Fund.

The widely distributed polychaete family Polynoidae Kinberg, 1856 is found across all oceans and from shallow to deep waters, including deep-sea hydrothermal vents and hydrocarbon seeps. Taxa inhabiting chemosynthesis-based ecosystems are often endemic to those specific habitats commonly targeted by deep-sea mining, and understanding their species diversity is essential for shaping conservation plans. Here, we report two previously undescribed scale-worms in the genus Branchinotogluma Pettibone, 1985 from the Off Hatsushima hydrocarbon seep of Sagami Bay and the Nikko Seamount hydrothermal vent on the Izu-Ogasawara Arc, and describe them as B. nikkoensis sp. nov. and B. sagamiensis sp. nov. Branchinotogluma nikkoensis sp. nov. is distinguished from the known species by the following characters: i) ventral segmental lamellae near ventral bases of neuropodia present on segments 13–17, ii) dorsal tentacular cirri being longer than ventral tentacular cirri, iii) absence of dorsal tubercles. Branchinotogluma sagamiensis sp. nov. can be differentiated from other congeners by i) 20 segments, ii) dorsal tentacular cirri being longer than ventral tentacular cirri, iii) ventral segmental lamellae near ventral bases of neuropodia present on segments 13–18, and iv) thin median antennae. The two new species are distinct in both morphology and four gene sequences from the only two species previously known from Japan including Branchinotogluma japonicus (Miura & Hashimoto, 1991) and B. elytropapillata Zhang, Chen & Qiu, 2018, originally described from Kaikata Seamount vent on the Izu-Ogasawara Arc and Okinawa Trough, respectively

Updated key to genera of Polynoinae sensu lato present in the Northeast Atlantic incl. the Mediterranean Sea Based on Barnich & Fiege (2003, 2009, 2010), Barnich (2011), Barnich et al. (2017), Chambers & Muir (1997), Charles et al. (2014), Fiege & Barnich (2009), Hartmann-Schröder (1996), Jourde et. al (2015), Núñez et al. (2015), Pettibone (1963), Ravara & Cunha (2016), Taboada et al. (2019) and this study. In order to allow for identification of anterior fragments, the current key avoids, where possible, the use of numbers of elytra and segments as main distinguishing character. 1. Dorsal tubercles T-shaped. (Cephalic peaks absent. Lateral antennae terminoventral. More than 15 pairs of elytra. More than 50 segments)..................................................... Acholoe Claparède, 1870 – Dorsal tubercles nodular................................................................................................................... 2 2. First three pairs of elytra modified, with translucent central area. (Cephalic peaks absent or present. Lateral antennae ventral. 15 pairs of elytra. Fewer than 50 segments)..................................................................................................................................................... Gorgoniapolynoe Pettibone, 1991 – First three pairs of elytra not modified............................................................................................. 3 3. Dorsum with one or more median nodules per segment, starting from segment 2. (Cephalic peaks absent. Lateral antennae ventral. 18 pairs of elytra. Fewer than 50 segments)..................................................................................................................................................... Bathynoe Ditlevsen, 1917 – Dorsum without median nodules in anterior segments (may start later).......................................... 4 4. Prostomium with cephalic peaks (can be small or masked when prostomium in bad condition).... 5 – Prostomium without cephalic peaks............................................................................................... 18 5. Notochaetae with two kinds of tips. Lateral antennae ventral or terminoventral............................. 6 – Notochaetae all with similar, stout tip. Lateral antennae ventral...................................................... 9 6. Some notochaetae with slender furcate tip, most others with stout, entire tip. Cephalic peaks small. Lateral antennae terminoventral (15 pairs of elytra. Fewer than 50 segments).................................................................................................................................................. Pettibonesia Nemésio, 2006 – Notochaetae different. Cephalic peaks obvious. Lateral antennae ventral....................................... 7 7. Long notochaetae with stout, blunt tip, short notochaetae abruptly tapering to sharp, pointed tip (15 pairs of elytra. Fewer than 50 segments)..................................... Neolagisca Barnich & Fiege, 2000 – Most notochaetae with elongate, capillary tip.................................................................................. 8 8. Neurochaetae all with short, unidentate tip. Notochaetae numerous. Elytra large, covering dorsum. Dorsum without median nodules (15 pairs of elytra. Fewer than 50 segments).................................................................................................................................................... Gattyana McIntosh, 1897 – Neurochaetae with two types of tip: short, bi- or unidentate or elongate, capillary. Notochaetae few. Elytra small, leaving mid-dorsum uncovered. Dorsum with or without small median nodule starting in mid-body (15 pairs of elytra. More than 50 segments)............................. Enipo Malmgren, 1866 9. Dorsum with large median nodule starting in mid-body. Cephalic peaks small. (15 pairs of elytra. More than 50 segments)................................................................................ Polynoe Lamarck, 1818 – Dorsum without median nodules. Cephalic peaks obvious............................................................ 10 10. Neurochaetae distally bill-shaped. Neuropodia elongate, without supra-acicular process (15 pairs of elytra. Fewer than 50 segments)......................................................... Robertianella McIntosh, 1885 – Neurochaetae otherwise. Neuropodia with supra-acicular process.................................................11 11. Some neurochaetae with hairy, penicillate tip. (15–16 pairs of elytra. Fewer than 50 segments)................................................................................................................ Austrolaenilla Bergström, 1916 – Neurochaetae otherwise.................................................................................................................. 12 12. Some neurochaetae slender with furcate tip. (15 pairs of elytra. Fewer than 50 segments)................................................................................................................................. Eucranta Malmgren, 1866 – Neurochaetae otherwise.................................................................................................................. 13 13. All neurochaetae with unidentate tip.............................................................................................. 14 – Neurochaetae with bi- and unidentate tip....................................................................................... 15 14. Neurochaetae all with stout tip (15 pairs of elytra. Fewer than 50 segments)........................................................................................................................................................... Eunoe Malmgren, 1866 – At least some neurochaetae with elongate, capillary tip (15 pairs of elytra. Fewer than 50 segments)................................................................................................. Bylgides Chamberlin, 1919 15. Notopodium prominent. More than 50 segments, long tail uncovered by elytra. 15 pairs of elytra.................................................................................................................. Neopolynoe Loshamn, 1981 – Notopodium reduced. Fewer than 50 segments, dorsum covered by elytra or at most short tail uncovered........................................................................................................................................ 16 16. Elytra 18 pairs (elytral characters distinctive).................................. Acanthicolepis McIntosh, 1900 – Elytra 16 or 15 pairs....................................................................................................................... 17 17. Elytra 16 pairs (elytral characters distinctive)............................................. Leucia Malmgren, 1867 – Elytra 15 pairs (elytral characters distinctive).......................................... Harmothoe Kinberg, 1856 18. Neurochaetae with semilunar pockets. Lateral antennae ventral.................................................... 19 – Neurochaetae without semilunar pockets. Lateral antennae ventral or terminoventral.................. 20 19. Neuropodial acicular lobe rounded, neuroaciculum not penetrating epidermis. Notochaetae with few, scattered rows of spines (15 pairs of elytra. More than 50 segments)............................................................................................................................................................. Adyte Saint-Jospeh, 1899 – Neuropodial acicular lobe pointed, neuroaciculum penetrating epidermis.Notochaetae with numerous rows of spines (15–16 pairs of elytra. Fewer than 50 segments)............... Subadyte Pettibone, 1969 20. Anteriormost neuropodia with stout hooks. Lateral antennae ventral or terminoventral (15 pairs of elytra. Fewer than 50 segments).................................................. Australaugeneria Pettibone, 1969 – Anteriormost neuropodia without hooks (15 pairs of elytra. Fewer than 50 segments)................. 21 21. Lateral antennae terminoventral. Neurochaetae all stout. (Notopodium reduced)............................................................................................................................................ Malmgrenia McIntosh, 1874 – Lateral antennae ventral. Neurochaetae with stout or capillary tip................................................ 22 22. Notopodium reduced. Neurochaetae all with stout, entire tip. Notochaetae very few (2-3), stout with faint rows of spines............................................................................................ Webbnesia gen. nov. – Notopodium prominent. Most neurochaetae with slender, capillary tip, some with stout, furcate tip. Notochaetae few, very stout, acicular, smooth......................................... Melaenis Malmgren, 1866, Published as part of Núñez, Jorge, Barnich, Ruth & Monterroso, Óscar, 2022, A new genus and species of Polynoidae (Annelida: Polychaeta) from the Canary Islands, and update on taxa present in the Northeast Atlantic, pp. 55-74 in European Journal of Taxonomy 846 (1) on pages 69-71, DOI: 10.5852/ejt.2022.846.1965, http://zenodo.org/record/7277225, {"references":["Barnich R. & Fiege D. 2003. The Aphroditoidea (Annelida, Polychaeta) of the Mediterranean Sea. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft 559: 1 - 167.","Barnich R. 2011. Identification of scale worms in British and Irish waters. NMBAQC 2010 taxonomic workshop, Dove Marine Laboratory: 1 - 52.","Barnich R., Dietrich A., Hager T. & Fiege D. 2017. On the genera Malmgrenia McIntosh, 1874 and Pettibonesia Nemesio, 2006 in the Northeast Atlantic and Mediterranean Sea, with descriptions of two new species (Polychaeta: Polynoidae). Marine Biodiversity 49: 315 - 324. https: // doi. org / 10.1007 / s 12526 - 017 - 0802 - 4","Chambers S. J. & Muir A. I. 1997. Polychaetes: British Chrysopetaloidea, Pisionoidea and Aphroditoidea. Synopses of the British Fauna 54: 1 - 202.","Charles F., Guarini J. M. & Fanfard S. 2014. First record of Harmothoe mariannae Barnich & Fiege, 2009 (Polychaeta: Polynoidae) in the Mediterranean Sea, France. Check List 10 (3): 607 - 608. https: // doi. org / 10.15560 / 10.3.607","Barnich R. & Fiege D. 2009. Revision of the genus Harmothoe Kinberg, 1856 (Polychaeta: Polynoidae) in the Northeast Atlantic. Zootaxa 2104: 1 - 76. https: // doi. org / 10.11646 / zootaxa. 2104.1.1","Hartmann-Schroder G. 1996. Annelida, Borstenwurmer, Polychaeta [Annelida, bristleworms, Polychaeta]. 2 nd revised Ed. The Fauna of Germany and Adjacent Seas with their Characteristics and Ecology 58. Gustav Fischer, Jena, Germany.","Nunez J., Barnich R., Brito M. del C. & Fiege D. 2015. Familia Polynoidae Kinberg, 1855. In: Ramos et al. (eds) Annelida Polychaeta IV. Parapar J., Moreira J., Nunez J., Barnich R., Brito M. del C., Fiege D., Capaccioni-Azzati R. & El-Haddad M. Fauna Iberica, Vol. 41: 216 - 251. Museo Nacional de Ciencias Naturales, CSIC, Madrid.","Pettibone M. H. 1963. Marine polychaete worms of the New England region. 1. Aphroditidae through Trochochaetidae. U. S. National Museum Bulletin 227 (1): 1 - 356. https: // doi. org / 10.5479 / si. 03629236.227.1","Ravara A. & Cunha M. R. 2016. Two new species of scale worms (Polychaeta: Aphroditiformia) from deep-sea habitats in the Gulf of Cadiz (NE Atlantic). Zootaxa 4097 (3): 442 - 450. https: // doi. org / 10.11646 / zootaxa. 4097.3.12","Taboada S., Silva A. S., Neal L., Cristobo J., Rios P., Alvarez-Campos P., Hestetun J. T., Koutsouveli V., Sherlock E. & Riesgo A. 2019. Insights into the symbiotic relationship between scale worms and carnivorous sponges (Cladorhizidae, Chondrocladia). Deep-Sea Research Part I: Oceanographic Research Papers 156 (103191): 1 - 14. https: // doi. org / 10.1016 / j. dsr. 2019.103191","McIntosh W. C. 1885. Report on the Annelida Polychaeta collected by H. M. S. Challenger during the years 1873 - 76. Report on the Scientific Results of the Voyage of H. S. M. \" Challenger \", Zoology 12: 1 - 554."]}

Genus Webbnesia gen. nov. urn:lsid:zoobank.org:act: 33FB3584-DCFC-4B0E-9D1D-ED8AF67F15E9 Tables 2–3 Type species Webbnesia maculata gen. et sp. nov. designated herein. Diagnosis BODY. Flattened dorsoventrally, short, with fewer than 40 segments, more or less covered by elytra dorsally. ELYTRA. 15 pairs on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 26, 29 and 32. PROSTOMIUM. Bilobed, without cephalic peaks, with three antennae. Median antenna inserted in anterior notch, lateral antennae inserted ventrally. Two pairs of eyes. PARAPODIA. Biramous, notopodium reduced and neuropodium elongate. Notopodium with aciculum penetrating distally. Neuropodium with elongate prechaetal lobe and shorter postchaetal lobe; prechaetal acicular lobe with minute (i.e., reduced) supra-acicular process, aciculum penetrating subdistally. CHAETAE. Notochaetae and neurochaetae stout, with rows of spines and entire tip. Etymology The genus name is a combination of the name Webb and the Greek word ‘ nes ’ (= ‘island’); gender feminine. ‘Webbnesia’ refers to a new ecoregion defined by Freitas et al. (2019) and co-authored by one of us (JN) which includes the Canary, Savage and Madeira Islands. Remarks Among the genera currently attributed to Polynoinae sensu lato, only Hermadion Kinberg, 1856, Antinoe Kinberg, 1856 and Malmgrenia McIntosh, 1874 (see Pettibone 1993; Bock et al. 2010 and Barnich et al. 2017) share the following diagnostic characters with Webbnesia gen. nov.: 15 pairs of elytra, fewer than 50 segments (i.e., short-bodied), cephalic peaks absent, noto-and neurochaetae all of same type, stout, without semi-lunar pockets. Webbnesia and Hermadion have ventrally inserted lateral antennae, but the shape of their parapodia is different. The notopodium of Hermadion is prominent, nearly as long as the neuropodium, while the new genus is characterised by a minute, reduced notopodium (see Tables 2–3). In Malmgrenia and Antinoe the parapodia are similar to those of Webbnesia, but the main difference is the insertion of the lateral antennae, which is ventral in Webbnesia and terminoventral in the two other genera. Among the polynoid genera sharing the diagnostic characters listed above, the combination of ventrally inserted antennae and a reduced notopodium is unique and justifies the erection of a new genus (see Table 2).

Webbnesia maculata gen. et sp. nov. urn:lsid:zoobank.org:act: 3128B356-28DC-4072-BC95-7DC8454AC1D3 Figs 2–6, Tables 2–3 Diagnosis PROSTOMIUM. Without cephalic peaks. Lateral antennae inserted ventrally. Two pairs of eyes, anterior pair dorsolateral, posterior pair dorsal. ELYTRA. With smooth margins, surface with scattered, conical microtubercles and pigmented patches. ANTENNAE AND CIRRI. Tapering, papillate. PARAPODIA. With reduced notopodium and prominent neuropodium; neuropodium with minute (i.e., reduced) supra-acicular process, aciculum penetrating subdistally. CHAETAE. Notochaetae stout with faint rows of spines and entire tip. Neurochaetae stout with distinct rows of spines and falcate, entire tip. Etymology The species epithet refers to the characteristic pigmented patches on the elytra, described by the Latin word ‘ maculatus ’ in its female form. Material examined Holotype CANARY ISLANDS • ovigerous ♀ (complete, with 33 segments); NE Atlantic, east coast of Gran Canaria, off Tufía; 27°57.91′ N, 15°22.63′ W; 27 m depth; Feb. 2019; fine sands; TFMCBM-AN/246. Paratypes CANARY ISLANDS • 1 spec. (anterior fragment of 11 segments); NE Atlantic, south coast of Gran Canaria, off Castillo del Romeral; 27°47.79′ N, 15°24.40′ W; 39 m depth; Oct. 2020; coarse sands; TFMCBM-AN/247 • 1 spec. (posterior fragment of 12 segments); NE Atlantic, south coast of Gran Canaria, off Castillo del Romeral; 27°47.73′ N, 15°23.49′ W; 60 m depth; Oct. 2020; coarse sands; TFMCBM-AN/248 • 1 spec. (anterior fragment of 16 segments); NE Atlantic, south coast of Tenerife, off Granadilla; 28°3.56′ N, 16°30.20′ W; 22 m depth; 18 Sep. 2013; coarse sands; SMF 32262. Description of holotype MEASUREMENTS. Holotype, complete specimen of 8 mm length and 2 mm width in anterior body region. BODY. Flattened dorsoventrally, short, with 33 segments, dorsum covered by elytra (Fig. 3A); ovigerous female (Fig. 4C–D). PROSTOMIUM. Cephalic peaks absent, lobes anteriorly rounded. Median antenna with ceratophore in anterior notch, style tapering, papillate; lateral antennae with ceratophores inserted ventrally, styles tapering, papillate. Anterior pair of eyes dorsolateral in front of widest part of prostomium, posterior pair dorsal near posterior margin (Figs 2A, 3B). TENTACULOPHORES. Inserted laterally to prostomium, with a pair of dorsal and ventral tentacular cirri; styles tapering, papillate (Figs 2A, 3B). ELYTRA. Fifteen pairs on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 26, 29 and 32. Elytral margins smooth; surface with scattered, conical microtubercles and five pigmented patches (Figs 2B, 3A–B, 4A–B). CIRRI. Dorsal cirri from segment3 on segments without elytra; cirrophore inserted dorsally on notopodium; style tapering, papillate (Figs 2A, C, 3A–D, 4D). Ventral cirri from segment 2 on all segments; first pair distinctly larger than following; style tapering, papillate (Figs 2C, 3D). Pair of pygidial cirri similar to dorsal cirri. DORSAL TUBERCLES. Conical, one pair present on all cirrigerous segments, situated on dorsum in line with elytrophores of adjacent segments (Fig. 2A, C). PARAPODIA. Notopodium reduced, with notoaciculum penetrating distally (may be withdrawn). Neuropodium more prominent, with elongate, conical prechaetal lobe and shorter, rounded postchaetal lobe; prechaetal lobe acicular with minute (i.e., reduced) supra-acicular process and neuroaciculum penetrating subdistally (Figs 2C–D, 4D, 5). CHAETAE. Notochaetae few (2–3), stout, with faint rows of spines and blunt, entire tip (Figs 2C–E, 6A). Neurochaetae more numerous (up to 18), stout, with falcate, entire (i.e., unidentate) tip; upper neurochaetae distally rather straight and spinose region elongate with pronounced rows of spines; middle and lower neurochaetae distally more curved and spinose region shorter with less marked rows of spines (Figs 2C–D, F, 4D, 6B–D). Pigmentation (animals preserved) (Figs 2A–B, 3A–D, 4A) Body dorsally mostly white with brown patches; ventrally with 13 intersegmental, incomplete transverse bands in posterior body region. Prostomial lobes with diffuse pigmentation; basal part of median antenna and all of lateral antennae darkly pigmented. Tentacular cirri unpigmented. Dorsal and ventral cirri pigmented basally throughout body, also pygidial cirri similarly pigmented. Elytra usually with five pigmented patches: one circular above place of attachement to elytrophore, the others irregularlyshaped, two on the inner lateral part and two on the posterior part. Distribution and habitat NE Atlantic, Canary Islands: E and S of Gran Canaria and S of Tenerife; in 22 to 60 m depth. The substrate at the Tufía station is characterised by areas of fine sand and poorly consolidated maerl. The faunal composition is dominated by the polychaetes Paradoneis armata Glémarec, 1966 and Aponuphis ornata (Fauvel, 1928) and the crustaceans Apseudopsis rogi Esquete, 2016 and Urothoe marina (Spence Bate, 1857). At the Castillo del Romeral stations the substrate is characterised by gravel and coarse organogenic sand. The dominant polychaetes are Pisione guanche San Martín, López &Núñez, 1999 and Syllis gerundensis (Alós & Campoy, 1981); the most abundant species are the bivalve Gouldia minima (Montagu, 1803) and the amphipod Photis longicaudata (Spence Bate & Westwood, 1862). At the Granadilla station the substrate is characterised by maerl and coarse sand. The faunal composition is dominated by the amphipod Animoceradocus semiserratus (Spence Bate, 1862) and the polychaetes Chone filicaudata Southern, 1914 and Aponuphis bilineata (Baird, 1870).

POLLENTIA PEREZI SP. NOV. (FIGS 3, 4, 5, 6) Zoobank registration: urn: lsid: zoobank. org:act: DF4ED4DA-818A-49E0-9996-AFDB2FAD73FA Type material: Cova des Bastons (also known as Cave C-11), Alcúdia, Mallorca, Balearic Islands, 39°53 ′ 03.1 ″ N, 3°11 ′ 45.1 ″ E. Holotype: specimen preserved in ethanol; collected by J. Pérez at 17 m depth on bare rock with some patches of calcareous silt, 11 March 2020 (MNCN 16.01 /18955) (Supporting Information Video S 15). Paratype: specimen preserved in ethanol, divided into two fragments, same collector, locality, substratum and depth, 30 June 2019 (MNCN 16.01 /18956). Additional material examined: specimen preserved in RNAlater, same collector, locality, substratum and depth as holotype (deposited at IMEDEA collection) (see Supporting Information Video S16). Description of holotype: Body length 18 mm, maximum width 6 mm at midbody segments (including parapodia; *A pair of large eyes was described in Bathymoorea renotubulata by Pettibone (1967) and in Bathymoorea lucasi by Bonifácio & Menot (2019), but these are considered herein as potential misinterpretations. excluding chaetae). Body 27-segmented, flattened dorsoventrally, anterior margin blunt, tapering posteriorly (Fig. 4). Specimen pale when alive, with some tiny brown spots scattered over dorsum, forming narrow segmental transverse bands near base of notopodia and elytrophores, and on ventrum near base of parapodia (Figs 4, 5C, D). Head intensely coloured dark red (pigmented brain visible through translucent epithelium; Figs 4A, C, D, 5A–C). Prostomium bilobed, wider than long, with lobes extending anteriorly to form ceratophores of lateral antennae (Figs 5A–C, 6A). Median antenna inserted proximal to anterior margin of prostomium; ceratophore bulbous, longer than wide (Figs 5B, 6A); style tapering, reaching segment 3 (Fig. 5B). Lateral antennae with styles also tapering, shorter than median antenna (Fig. 5A, B). Median and lateral antennae with scattered long papillae on styles (Fig. 6A–C). Palps stout and longer than antennae, reaching segment 6, heavily wrinkled and covered with minute oval papillae (Figs 4D, 5A, 6B, E, F). Eyes absent (Figs 4A, C, D, 5A–C). Tentacular segment (segment 1) with short lobe inserted lateral to prostomium; aciculae not penetrating epidermis; bundle of about six notochaetae (Figs 5A, C, 6B, H). One pair of tentacular cirri present on each side of segment; tentaculophores longer than wide, ventral larger than dorsal (Fig. 6H); tentacular styles tapering, dorsal and ventral of similar length, reaching segment 5 (Fig. 4D); styles covered with elongated papillae (Fig. 6I). Mouth lips strongly developed, protruding when pharynx not everted (Fig. 5E). Facial tubercle absent, but slightly inflated longitudinal ridge present on upper lip (Fig. 6B, G). Pharynx not everted in holotype and dissected in paratype, with ring of elongate, blunt subconical papillae of similar size (Fig. 6M, not counted) and two pairs of jaws with smooth margins (Fig. 6N). Segment 2 devoid of nuchal pads and folds (Fig. 6A–C). Thirteen pairs of elytra, one on each of segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23 and 26. Elytra large, covering dorsum, lacking papillae, each with microtubercles along external edge (Fig. 7A–D) and on dorsal surface of posterior third (Fig. 7E). Surface of anterior part of elytra smooth (Fig. 7F). Dorsal cirri present on non-elytrigerous segments from segment 3 onwards; cirrophores cylindrical (Fig. 8A–C); styles elongated and tapering, largely surpassing length of parapodia and chaetae, of similar length (Figs 4C, D, 8F, H), with some long, scattered papillae. Dorsal tubercles inconspicuous, low and conical, more evident on elytrigerous segments (Fig. 8B). Segment 2 with subbirramous parapodia, enlarged conical acicular lobe, and noto- and neurochaetae (Fig. 6H). Ventral cirri of segment 2 (buccal cirri) inserted basally, with large cirrophores; stylode longer than subsequent counterparts, with elongated papillae (Fig. 6I). Rest of segments also with subbiramous parapodia and with thin and long, tapering acicular lobes projecting on both rami; notoacicular lobe shorter than neuroacicular and hidden under the inferior notochaetae (Fig. 8B); neuroacicular lobe conspicuous (Fig. 8E, G); noto- and neuroaciculae not penetrating into lobes (Fig. 8D, E, G). Notopodia rounded, one-third the length of neuropodium; latter subconical, with further indistinct lobes other than the acicular projections (Fig. 8E–G). Ventral cirri inserted at midlength of neuropodia (Fig. 8E–G), with short ceratophore and smooth, tapering style reaching about midlength of parapodia (Fig. 8A, B). Styles of ventral cirri of segments 2 and 3 longer than subsequent counterparts, with elongated papillae (Fig. 8H–K); styles from segment 4 onwards all similar in length, without papillae (Fig. 8I, L). Semispherical papillae ventrally at base of parapodia (Fig. 8M). Notochaetae of all segments similar, of only one type (~20 on parapodia of anterior and midbody segments), stouter than neurochaetae, arranged in dense, radiating tufts (Fig. 9A, B). Notochaetae smooth and straight basally, slightly curved and tapering, with welldeveloped spinous rows along convex margin (Fig. 9 A-C) and pointed, conical tips. Two types of neurochaetae (30–40 on parapodia of midbody segments) arranged in transverse rows. Superior neurochaetae flattened, with one side bearing faintly spinous rows (Fig. 9 D-F); tip tridentate, with a slightly hooked tooth and two additional smaller teeth (Fig. 9F). Inferior neurochaetae shorter and thinner than superior counterparts, each with a cylindrical proximal half and a broader, lanceolate and flattened distal half; one of sides with well-developed spinous rows reaching the tip (Fig. 9G, H). Unpigmented nephridial papillae present at base of parapodia from segment 5 onwards, small and bulbous. Nephridial papillae from segment 8 onwards connect to posterior half of body through long ducts, visible under light microscopy. Pygidium small, rounded, not enclosed by last segment (Fig. 5G), with anus placed terminally. Pair of anal cirri longer than dorsal cirri. segment number. Intraspecific variability: Paratype, with 26 segments, measuring 18 mm long (including tentacular segment) and maximum width 6 mm at midbody segments (including parapodia; excluding chaetae). Pigmentation pattern similar to holotype (Figs 4, 5). Specimen with most elytra detached after preservation. Most other morphological features as for holotype (Figs 4, 5). Ecology: The first specimen was found and collected after scuba divers accidentally dropped an object on the sandy bottom of the cave and the animal escaped from danger, ascending to the water column (Supporting Information Videos S 15, S16). The other two specimens were each found in subsequent visits to the cave, crawling on the sediment. In all cases, specimens were found at 17 m depth in full-strength marine water (38 PSU) at 19 °C (Fig. 1C). Etymology: Species named after the Mallorcan cave diver Joan Pérez, who discovered the species and kindly offered the material to us for study. Remarks: The new Mallorcan cave polynoid bears an overall resemblance to members of the subfamily Eulagiscinae, in that they all share the terminal or subterminal insertion of the lateral antennae on anterior extensions of the prostomium, and the parapodia display notopodia shorter than neuropodia, unlike members of other related subfamilies (Wehe, 2006; Bonifácio & Menot, 2019). However, there are some morphological features that are unique among the current members of Eulagiscinae. The number of pairs of elytra, 13 in Pollentia perezi, is the lowest reported in the subfamily (Table 5; Pettibone, 1967, 1997; Bonifácio & Menot, 2019). In addition, the chaetal morphology and arrangement in Pollentia perezi are unique amongst members of Eulagiscinae and even Polynoidae. Thus, body segments from segment 2 onwards bear only stout notochaetae with spinous rows and pointed tips, similar to those described in Eulagisca and Bathymoorea lucasi (Table 5). Neurochaetae are of two types: the superior flattened, spinous and with a tridentate tip, whereas the inferior are shorter and thinner, lanceolate, spinous and tapering (Table 5). Furthermore, the superior neurochaetae are unique amongst those of Polynoidae, because they have a tridentate tip, with a main larger tooth and two additional smaller teeth. The inferior neurochaetae resemble the pectinate forms described in members of Eulepethidae (Pettibone, 1969). Both Eulagisca and Paraeulagisca are oculate (each bearing two pairs of eyes). The two nominal species of deep-sea Bathymoorea were described as bearing a pair of large eyes, but we consider this to be a misinterpretation of the brain occupying most of the prostomial lobes, as in the anchialine Pollentia perezi, which is eyeless. Like its deep-sea relatives, Pollentia perezi lacks body pigmentation except for a few scattered spots distributed as described above., Published as part of Capa, María, Pons, Joan & Jaume, Damià, 2022, Discovery of a new scale worm (Annelida: Polynoidae) with presumed deep-sea affinities from an anchialine cave in the Balearic Islands (western Mediterranean), pp. 479-502 in Zoological Journal of the Linnean Society 196 on pages 490-498, DOI: 10.1093/zoolinnean/zlac046, http://zenodo.org/record/7035469, {"references":["Pettibone MH. 1967. Some bathyal Polynoids from central and northeastern Pacific (Polychaeta: Polynoids). Proceedings of the United States National Museum 121: 1 - 15.","Bonifacio P, Menot L. 2019. New genera and species from the Equatorial Pacific provide phylogenetic insights into deepsea Polynoidae (Annelida). Zoological Journal of the Linnean Society 185: 555 - 635.","Wehe T. 2006. Revision of the scale worms (Polychaeta: Aphroditoidea) occurring in the seas surrounding the Arabian Peninsula. Part I: Polynoidae. Fauna of Arabia 22: 23 - 197.","Pettibone MH. 1997. Revision of the scaleworm genus Eulagisca McIntosh (Polychaeta: Polynoidae) with the erection of the subfamily Eugaliscinae and the new genus Pareulagisca. Proceedings of the Biological Society of Washington 110: 537 - 551."]}

POLLENTIA GEN. NOV. Zoobank registration: urn: lsid: zoobank. org: act: A 0 C C E E 3 2 - 9 4 F E - 4 4 C 7 - B B 1 D - C4DD85D58FB5 Diagnosis: Body flattened dorsoventrally, with ≤ 27 segments (Fig. 4). Prostomium bilobed (Fig. 5A–C). Frontal filaments absent. Eyes absent (Fig. 5A–C). Median and lateral antennae present; lateral antennae inserted subterminally on extensions of prostomium (Fig. 5A–C). Facial tubercle absent. Tentaculophores with acicula and chaetae (Figs 5, 6B). Dorsal tubercles present. Elytrophores large, 13 pairs: one pair on each of segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23 and 26. Elytra large, covering dorsum, lacking papillae, each with microtubercles along external edge and posterior dorsal surface. Parapodia subbiramous; noto- and neuropodia with elongate acicular lobe. Notochaetae with spinous rows and pointed tips. Neurochaetae numerous, of two types: superior, flattened, with spinous rows and with tridentate tip; and inferior, shorter and thinner, lanceolate and pectinate, with spinous rows and tapering. Nephridial papillae present from segment 5 onwards. Remarks: The erection of a new genus is required to accommodate this taxon because it shows some unique features not reported in any other member of the subfamily Eulagiscinae, namely, the display of 13 pairs of elytra and the morphology and arrangement of noto- and neurochaetae. In addition, Pollentia shows a unique combination of features: eyelessness; tentaculophores bearing acicula and chaetae; nephridial papillae present from segment 5 onwards; only one type of notochaetae present from segment 2 onwards, stout and spinous; and two types of neurochaetae: superior flattened, spinous and tridentate; and inferior smaller, lanceolate and pectinate with spinous rows reaching the tip. Etymology: Generic name refers to Pollentia, an ancient Roman city located in the current Mallorcan municipality of Alcúdia, where the cave harbouring the new taxon is located. Gender feminine. Type species: Pollentia perezi sp. nov., described herein, by monotypy.

Branchipolynoe onnuriensis sp. nov. (Figs. 1–4) urn:lsid:zoobank.org:act: 7E5DB4C2-75E2-4AD2-9BE7- A4860812BBC9 Material examined: Six specimens. Holotype (B_S_ MA_0031740) and five paratypes (B_S_MS_00031741- 5), collected from the OVF on the northern Central Indian Ridge (st. GTV 1906 - 11°24.96'S, 66°25.397'E, 2064 m depth). Etymology: Named in honor of the discoverer of the OVF. Ecology: The new species is only known to occur in association with the hydrothermal vent mussel Gigantidas vrijenhoeki Jang et al. 2020. It lives inside the pallial cavity of the host (Fig. S1). The deep-sea OVF in the Indian Ocean is a hydrothermal system characterized by low-temperature diffuse emissions with high concentrations of dissolved methane (Jang et al. 2020). Description: Body slightly tapered anteriorly and posteriorly, flattened ventrally and arched dorsally, with 21 segments, first segment achaetous (Fig. 1A, B). Ten pairs of elytrophores and elytra on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, and 19; elytra moderately large, smooth, oval without border papillae (Fig. 2C– F), covering the dorsum in the anterior and posterior regions, but leaving the mid-dorsum partially uncovered (Fig. 1A, B). Cirrophorous segments with short cylindrical cirrophores and short, smooth dorsal cirri with short slender tips, tapering gradually, exceeding the anterior and ventral cirri, not extending past the tips of neurochaetae (Fig. 1A). Prostomium ellipsoidal, bilobed, with rounded anterior lobes. A pair of short conical palps and short conical median antennae between the two anterior lobes (Fig. 1C). Median antenna and palps smooth, tapering to slender tip; palps extending beyond prostomium. Prostomium lacking frontal peaks, eyes, and lateral antennae. First segment with two pairs of tentacular cirri, fused to the prostomium; tentacular cirri smooth, slightly slender, not exceeding prostomium length (Fig. 1C). Thick, muscular pharynx with five pairs of dorsal and ventral small, sac-like terminal papillae surrounding the mouth (Fig. 2A). © 2022 Academia Sinica, Taiwan Branchiae on segments 3–21, dense, arborescent, with short terminal filaments (Fig. 2B), not extending beyond the elytral border, gradually decreasing in size anteriorly and posteriorly, separated into two types emerging dorsally and ventrally, respectively. Dorsal tubercles non-discernible. Parapodia subbiramous. Notopodia smaller than neuropodia, with few notochaetae projecting beyond notopodia (Fig. S2). Neuropodia large, rounded, enclosing numerous neurochaetae with rounded lobes. Notochaetae smooth; stouter and shorter than neurochaetae (Fig. 3A). Notochaetae few (up to 8 per parapodium), more numerous in middle and posterior than anterior segments, slightly tapering, with serrated distal parts, rounded unidentate tips and shafts with indistinctive serrations (Fig. 3B–D). Neurochaetae numerous, more abundant on middle than anterior and posterior segments, arranged as a lateral fan, tapering, with subdistal swelling and small spines along the edge, serrations starting at the midpoint of the expanded distal part on only one side and extending distally; supraacicular neurochaetae long, stout, with slender tips, bidentate, with hooked distal teeth, serrated distally and flattened on one side; subacicular neurochaetae similar to supraacicular but with shorter distal serrated parts (Fig. 4). © 2022 Academia Sinica, Taiwan Ventral cirri smooth, small, lacking papillae, inserted in the middle of neuropodia; projecting anteriorly (Fig. 1D). Nephridial papillae ventral, on segments 11 and 12 in females, long, reaching the next segment, projecting posteriorly (Fig. 1D). Pygidium small, round with a pair of short, stout, tapered anal cirri, not fused (Fig. 1B). Morphological variation: Holotype 28 mm long and 13 mm wide (including parapodia); paratypes 23– 31 mm long and 8–14 mm wide (including parapodia). All specimens showing nephridial papillae on segments 11 and 12, suggesting all were females. Remarks: Nine species of Branchipolynoe have been described (Pettibone 1984 1986; Miura and Hashimoto 1991; Zhou et al. 2017; Lindgren et al. 2019; Wu et al. 2019). The diagnostic characteristics of this genus were established based on Branchipolynoe symmytilida and amended based on B. seepensis to include the first position of branchiae, the presence of cephalic peaks, and the form of parapodia (Pettibone 1984 1986). Subsequently, B. longqiensis was described from the Indian Ocean and five additional species were described from the Pacific Ocean (Lindgren et al. 2019; Zhou et al. 2017) (Table S2). Members of this genus have 21 segments, 10 elytra partially covering the dorsal region and bilobed prostomium (except B. kajsae) lacking cephalic peaks (except B. symmytilida). Branchipolynoe onnuriensis sp. nov. most closely resembles B. longqiensis and B. tjiasmantoi in having branchiae starting on the third segment and subbiramous parapodia, but differs in the two latter species have short, rounded notopodial acicular lobes, inconspicuous pharyngeal papillae, and different tip shapes of their sub-acicular neurochaetae (Table S3)., Published as part of Kim, Sang Lyeol, Choi, Hyeongwoo, Eyun, Seong-il, Kim, Dongsung & Yu, Ok Hwan, 2022, A New Branchipolynoe (Aphroditiformia: Polynoidae) Scale Worm from the Onnuri Deep-sea Hydrothermal Vent Field, Northern Central Indian Ridge, pp. 1-14 in Zoological Studies 61 (21) on pages 4-6, DOI: 10.6620/ZS.2022.61-21, http://zenodo.org/record/8075105, {"references":["Jang SJ, Ho PT, Jun SY, Kim D, Won YJ. 2020. A newly discovered Gigantidas bivalve mussel from the Onnuri Vent Field in the northern Central Indian Ridge. Deep Res Part I Oceanogr Res Pap 161: 103299. doi: 10.1016 / j. dsr. 2020.103299.","Pettibone M. 1984. A new scale-worm commensal with deepsea mussels on the Galapagos hydrothermal vent (Polychaeta, Polynoidae). Proc Biol Soc Wash 97: 226 - 239.","Pettibone M. 1986. A new scale-worm commensal with deep-sea mussels in the seep-sites at the Florida escarpment in the eastern Gulf of Mexico (Polychaeta: Polynoidae: Branchipolynoinae). Proc Biol Soc Wash 99: 444 - 451.","Miura T, Hashimoto J. 1991. Two new branchiate scale-worms (Polynoidae: Polychaeta) from the hydrothermal vent of the Okinawa through and the volcanic seamount off Chichijima Island. Proc Biol Soc Wash 104: 166 - 174.","Zhou Y, Zhang D, Lu B, Wang C. 2017. Description of a new branchiate scale-worm (Polychaeta: Polynoidae) from the hydrothermal vent on Southwest Indian Ocean Ridge. Zootaxa 4282: 123 - 134. doi: 10.11646 / zootaxa. 4282.1.7.","Lindgren J, Hatch AS, Hourdez S, Seid CA, Rouse GW. 2019. Phylogeny and biogeography of Branchipolynoe (Polynoidae, Phyllodocida, Aciculata, Annelida), with descriptions of five new species from methane seeps and hydrothermal vents. Diversity 11: 153. doi: 10.3390 / d 11090153.","Wu X, Zhan Z, Xu K. 2019. Two new and two rarely known species of Branchinotogluma (Annelida: Polynoidae) from deep-sea hydrothermal vents of the Manus Back-Arc basin, with remarks on the diversity and biogeography of vent polynoids. Deep Res Part I Oceanogr Res Pap 149: 103051. doi: 10.1016 / j. dsr. 2019.05.011."]}

Deep-sea hydrothermal vents are dynamic environments with exotic fauna, including bathymodiolin mussels and scale worm annelids that are often in close association. In this study, we found a new species of Branchipolynoe (Aphroditiformia: Polynoidae) living in the recently discovered mussel Gigantidas vrijenhoeki in deep-sea hydrothermal vents and methane seeps at 2,014–2,023 m depth. Based on the morphology and full mitochondrial genome sequences of specimens of Branchipolynoe from the Onnuri vent field (OVF) on the northern Central Indian Ridge, we describe them as a new species: Branchipolynoe onnuriensis sp. nov. This species resembles B. longqiensis and B. tjiasmantoi, but can be distinguished from these species by the shape of the notopodial acicular lobe and the tips of the subacicular neurochaetae. This identity is well-supported by genetic distance and phylogenetic analyses based on the mitochondrial c oxidase subunit I (COI) gene, with the new species being closest to the Western Pacific species B. tjiasmantoi. Phylogenetic analyses support close relationships between the Indian Ocean and Western Pacific hydrothermal polychaetes. Our data provide a foundation for exploring the evolutionary relationship between scale worms and bathymodiolin mussels.

Branchinotogluma sagamiensis sp. nov. [Japanese name: Sagami-tsunodashi-urokomushi] Zoobank LSID: urn:lsid:zoobank.org:act: 174E1034-D587-467D-BADA-E80B0D279451 Type locality: Hydrocarbon seep area, Off Hatsushima, Sagami Bay (36°00.957' N, 139°13.325' E), Japan, 867 m in depth. Material examined: Holotype (NSMT-Pol H-885): male, Sagami Bay, 867 m depth, ROV KM-ROV, R / V Kaimei, February, 2021, collected by CC. Paratype (NSMT-Pol P-886): one specimen, female, collected with the holotype. Description: Male 8 mm long, 3 mm wide (with parapodia, without chaetae), with 20 segments, flat (Fig. 4). Living colour purple-red. Body without dorsal tubercles. Ten pairs of elytra on segments 2, 4, 5, 7, and alternating segments to 19. Elytra transparent, without fringing papillae at outer margins, without microtubercles and macrotubercles. Bilobed prostomium pinkish in live specimens (whitish in ethanol) bilobed, with distinct anterior lobes; anterior lobes cylindrical, without conical frontal filaments (Figs 4C, 6A). Median antenna with short cylindrical ceratophore, inserted at anterior notch of prostomium (Figs 4C, 6A); style 0.5 mm, not papillate, thin and tapered. Lateral antennae absent. Eyes absent. Palps as long as ventral tentacular cirri (Figs 4C, 6A), whitish, smooth, tapered in tips. Dorsal and ventral tentacular cirri with tentaculophores lateral to prostomium. Dorsal tentacular cirri longer than ventral tentacular cirri. Dorsal and ventral tentacular cirri whitish, not papillated. One pair of short, thick ventral papillae present on segment 12 (Figs 4D, 6B). Ventral segmental lamellae near ventral bases of neuropodia present on segments 13–18 (Figs 4D, 6B). Pygidium with a pair of pygidial cirri, long and slender (Figs 4D, 6B). Parapodia biramous (Figs 5B, 6C). Notopodia shorter than neuropodia. Notopodia with short conical acicular lobes, on elytrigerous segments, with prominent bracts enclosing notochaetae dorsally and posteriorly (Figs 5B, 6C). About 50 notochaetae in each notopodium. Notochaetae short to long, with distinct rows of spines along one side, tapering to blunt tips, unidentate (Figs 5C, 6D), stouter than neurochaetae. Neuropodia with subconical prechaetal lobes tapering to sharp tips; post chaetal lobes shorter, rounded. Neurochaetae of one type, numerous, short to long, with borders finely spinous, tips slightly hooked and finely spinous, spines long and widely spaced in subdistal region, without semi-lunar pockets (Fig. 5D). Robust acicula in each ramum. Ventral cirri tapered, not papillated, attached on middle part of parapodia. On segment 2, ventral cirri elongated and projecting from neuropodia. Branchiae present from chaetigers 3 to 16, short, with 8–10 filaments, arborescent, two pouches per parapodium. Pharynx with four pairs of papillae terminally and two pairs of jaws.Jaws growing inwardly, with minute denticles. Variation: Paratypes 7 mm long, 2 mm wide. Ventral papillae absent in female specimen. Etymology: Named after the type locality (Sagami Bay). The specific name is an adjective. Distribution: Hydrocarbon seep area, 867 m, Off Hatsushima, Sagami Bay, Japan, Northwest Pacific Ocean. Remarks: This new species resembles Branchinotogluma trifurcus (Miura & Desbruyères, 1995) in having a cylindrical anterior lobe, absence of conical frontal filaments, and presence of short ventral papillae (Miura & Desbruyères 1995). The new species can be differentiated from B. trifurcus by the following features: i) 20 segments; ii) dorsal tentacular cirri longer than ventral tentacular cirri; iii) ventral segmental lamellae near ventral bases of neuropodia present on segments 13–18; iv) median antenna thin. This is the first record of Branchinotogluma from a hydrocarbon seep in Japan. Although categorized as a seep due to the typically cool temperature, the geofluid of the Off Hatsushima seep is probably hydrothermal in origin, since fluids as high as 11.6°C have been measured and the temperature of the end-member is said to be 34–54 °C (Tsunogai et al. 1996).

Branchinotogluma nikkoensis sp. nov. [Japanese name: Nikko-tsunodashi-urokomushi] Zoobank LSID: urn:lsid:zoobank.org:act: 380201B0-0231-4D7B-9AE8-1334B54A1FB0 (Figures 1–3) Type locality: Nikko Seamount hydrothermal vent field (23°04.855' N, 142°19.506' E), Japan, 458 m in depth. Material examined: Holotype (NSMT-Pol H-880): male, Nikko Seamount, 458 m depth, ROV KM-ROV, R / V Kaimei, December 8, 2020, collected by NJ. Paratypes (NSMT-Pol P-881–884): 4 specimens, male and female, collected with the holotype. Description: Male 7 mm long, 2 mm wide (with parapodia, without chaetae), with 21 segments, flat. Living colour purple-red (Fig. 1). Body without dorsal tubercles. Ten pairs of elytra on segments 2, 4, 5, 7, and alternating segments up to 19. Elytra transparent, without fringing papillae at outer margins, without microtubercles and macrotubercles. Bilobed prostomium pinkish in live (whitish in ethanol), with distinct anterior lobes; anterior lobes triangular, with conical frontal filaments. Median antenna with short cylindrical ceratophore (Figs 1C, 3A), inserted at anterior notch of prostomium; style 0.5 mm, not papillate, thin and tapered. Lateral antennae absent. Eyes absent. Palps as long as ventral tentacular cirri (Figs 1C, 3A), whitish, smooth. Dorsal and ventral tentacular cirri with tentaculophores lateral to prostomium. Dorsal tentacular cirri longer than ventral tentacular cirri. Dorsal and ventral tentacular cirri whitish, not papillated. One pair of long, thick ventral papillae present on segment 12. Ventral segmental lamellae near ventral bases of neuropodia present on segments 13–17. Pygidium with a pair of pygidial cirri (Fig. 3B). Parapodia biramous (Figs 2A, 3C). Notopodia shorter than neuropodia. Notopodia with short conical acicular lobes, on elytrigerous segments, with prominent bracts enclosing notochaetae dorsally and posteriorly (Figs 2B, 3C). About 50 notochaetae in each notopodium. Notochaetae short to long, with distinct rows of spines along one side, tapering to blunt tips, unidentate, stouter than neurochaetae (Figs 2C, 3D). Neuropodia with subconical prechaetal lobes tapering to sharp tips; post chaetal lobes shorter, rounded. Neurochaetae of one type, numerous, short to long, with borders finely spinous, tips slightly hooked and finely spinous, spines long and widely spaced in sub-distal region, without semi-lunar pockets (Figs 2D, 3E). Robust acicula in each rami. Ventral cirri tapered, not papillated, attached on middle part of parapodia. On segment 2, ventral cirri elongated and projecting from half of neuropodia. Branchiae present from chaetigers 3 to 16, short, digitate, with 2–3 filaments, two pouches per parapodium. Pharynx with six pairs of papillae terminally and two pairs of jaws. Jaws growing inwardly, with minute denticles. Variation: Paratypes 7–10 mm long, 2 mm wide without chaetae. Ventral papillae absent in female specimens. Etymology: Named after the type locality (Nikko Seamount). The specific name is an adjective. Distribution: Hydrothermal vent, 458 m, Nikko Seamount, Japan, Northwest Pacific Ocean. Remarks: This new species resembles Branchinotogluma hessleri Pettibone, 1985 in having a body with 21 segments, long and thick ventral papillae, bilobed prostomium, dentated jaws. The new species can be distinguished from B. hessleri by the following features: i) ventral segmental lamellae near ventral bases of neuropodia present on segments 13–17; ii) dorsal tentacular cirri longer than ventral tentacular cirri; iii) dorsal tubercles absent. Branchinotogluma japonicus (Miura & Hashimoto, 1991) is known from the Kaikata Seamount on the Izu-Ogasawara Arc and vents in the Okinawa Trough (Zhang et al. 2018) but has not been found in Nikko Seamount which is much further south to the Kaikata Seamount. Branchinotogluma elytropapillata Zhang, Chen & Qiu, 2018, was described from the Okinawa Trough and also has not been found at Nikko Seamount. The new species can be differentiated from these two other known Japanese species by having elytra with smooth edges and jaws with denticles., Published as part of Jimi, Naoto, Chen, Chong & Fujiwara, Yoshihiro, 2022, Two new species of Branchinotogluma (Polynoidae: Annelida) from chemosynthesis-based ecosystems in Japan, pp. 17-30 in Zootaxa 5138 (1) on pages 19-21, DOI: 10.11646/zootaxa.5138.1.2, http://zenodo.org/record/6552075, {"references":["Pettibone, M. H. (1985) Additional branchiate scale-worms (Polychaeta: Polynoidae) from Galapagos hydrothermal vent and rift-area off western Mexico at 21 ° N. Proceedings of the Biological Society of Washington, 98, 447 - 469.","Miura, T. & Hashimoto, J. (1991) Two new branchiate scaleworms (Polynoidae: Polychaeta) from the hydrothermal vent of the Okinawa Trough and the volcanic seamount off Chichijima Island. Proceedings of the Biological Society of Washington, 104, 166 - 174.","Zhang, Y., Chen, C. & Qiu, J. - W. (2018) Sexually dimorphic scale worms (Annelida: Polynoidae) from hydrothermal vents in the Okinawa Trough: two new species and two new sex morphs. Frontiers in Marine Science, 5, 112. https: // doi. org / 10.3389 / fmars. 2018.00112"]}

To increase the mitogenome data available for robust phylogeny, we sequenced the complete mitochondrial DNA of the scale worm Eunoe nodosa (Sars, 1861) in the family Polynoidae of the order Phyllod...

Genus Halosydna Kinberg, 1856 Type species: Halosydna patagonica Kinberg, 1856. Diagnosis. (from Salazar-Silva (2013)). Body thin, sub-rectangular, with 36 segments. Prostomium bilobed, without cephalic peaks; two pairs of small eyes, both pairs on posterior half of prostomium; three antennae, median antenna with ceratophore inserted frontally, with long, thick, style, subdistally expanded and tip filiform, surface not papillose; lateral antennae with ceratophores inserted terminally as prolongations of prostomium, at same level of ceratophore of median antenna, style of similar shape to median antenna. Two palps. Pharynx with nine pairs of marginal papillae and two pairs of hard jaws. Tentacular segment not visible dorsally, tentaculophores lateral to prostomium, tentacular cirri similar to antennae. Body with 18 pairs of elytra on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 28, 30, 31, 33. Posteriormost three segments with dorsal cirri. Elytra imbricated; margins with or without papillae; surface with papillae and/or tubercles (sclerotized or vesicular). Elytrophores rounded. Parapodia biramous. Notopodia shorter than neuropodia. Neuropodia distally truncated, with small rounded lobe near acicula tip. Dorsal cirri subdistally expanded and distally with filiform tip; cirrophore basally expanded. Dorsal tubercle inconspicuous. Ventral cirri shorter than neuropodia, tapering to fine tip. Notochaetae shorter than neurochaetae; with rows of spines; less abundant than neurochaetae; the smaller curved, with blunt tip, remaining ones slender tapering to capillary tips. Neurochaetae with rows of spines on upper region, tips entire or bidentate. Anus dorsal, between segments 35–36. Pygidium with one pair of anal cirri., Published as part of Valencia-Soto, David, 2021, Scale-bearing beauty: Intertidal scale-worms (Polychaeta: Polynoidae) from Punta Blanca (Arequipa, Peru), pp. 151-194 in Zootaxa 5032 (2) on page 166, DOI: 10.11646/zootaxa.5032.2.1, http://zenodo.org/record/5487023, {"references":["Kinberg, J. G. H. (1856) Nya slagten och arter af Annelider, Ofversigt af Kongl. Vetenskaps-Akademiens Forhhandlingar Stockholm, 12 (9 - 10), 381 - 388. Available from: https: // www. biodiversitylibrary. org / page / 15970133 (accessed 1 November 2020)","Salazar-Silva, P. (2013) Revision of Halosydna Kinberg, (Annelida: Polychaeta: Polynoidae) from the Tropical Eastern Pacific and Grand Caribbean with descriptions of new species. Journal of Natural History, 47, 1177 - 1242. Available from: https: // www. researchgate. net / publication / 263158752 _ Revision _ of _ Halosydna _ Kinberg _ 1856 _ Annelida _ Polychaeta _ Polynoidae _ from _ the _ Tropical _ Eastern _ Pacific _ and _ Grand _ Caribbean _ with _ descriptions _ of _ new _ species (accessed 18 January 2021) https: // doi. org / 10.1080 / 00222933.2012.752934"]}

Three species of polynoid polychaetes were collected during an exploratory sampling on the rocky shore of Punta Blanca in Arequipa, Peru. Lepidonotus aff. crosslandi peruana Hartmann-Schröder, 1962 differed from the nominal species by the presence of jaws without denticles and bidentate neurochaetae in the third parapodium while Harmothoe aff. hirsuta Johnson, 1897, differed by a disparate distribution of elytral ornamentations. Halosydna parva Kinberg, 1856 is newly recorded for the locality. Comparative tables between Lepidonotus, Halosydna and Harmothoe species recorded for Peru and the Pacific Coast of South America are provided.

In Australia, the deep-water (bathyal and abyssal) benthic invertebrate fauna is poorly known in comparison with that of shallow (subtidal and shelf) habitats. Benthic fauna from the deep eastern Australian margin was sampled systematically for the first time during 2017 RV ‘Investigator’ voyage ‘Sampling the Abyss’. Box core, Brenke sledge, and beam trawl samples were collected at one-degree intervals from Tasmania, 42°S, to southern Queensland, 24°S, from 900 to 4800 m depth. Annelids collected were identified by taxonomic experts on individual families around the world. A complete list of all identified species is presented, accompanied with brief morphological diagnoses, taxonomic remarks, and colour images. A total of more than 6000 annelid specimens consisting of 50 families (47 Polychaeta, one Echiura, two Sipuncula) and 214 species were recovered. Twenty-seven species were given valid names, 45 were assigned the qualifier cf., 87 the qualifier sp., and 55 species were considered new to science. Geographical ranges of 16 morphospecies extended along the eastern Australian margin to the Great Australian Bight, South Australia; however, these ranges need to be confirmed with genetic data. This work providing critical baseline biodiversity data on an important group of benthic invertebrates from a virtually unknown region of the world’s ocean will act as a springboard for future taxonomic and biogeographic studies in the area.

Chaetacanthus pomareae (Kinberg, 1856) Figures 17, 18 Lepidonotus pomareae Kinberg, 1856: 383; Kinberg 1858: 10, Pl. 3, Fig. 9, Pl. 10, Fig. 47; Seidler 1924: 20 (key), 32–33. Chaetacanthus pomareae: Hartman 1948: 27–29, Pl. 3, Figs 13, 14. Type material. Central South Pacific, French Polynesia. Holotype of Lepidonotus pomareae Kinberg, 1856, SMNH 395, Tahiti, 20°S, 150° W, Freg. Eugenie Exped. 1851–53. Diagnosis. Chaetacanthus with branchial filaments single, thick lobes; elytra with globular micropapillae and microtubercles; round macrotubercles larger on first pair of elytra; conical macrotubercles in following elytra, macrotubercles up to five times longer than wide, basally spinous, tips long, smooth; elytra without large, amber-colour macrotubercles arranged in honeycomb like groups. Description. Holotype in poor condition, without posterior end, 1.2 cm long, 0.3 cm wide, 23 segments. Data from description and illustrations by Kinberg (1858) given in parentheses. Prostomium bilobed, hexagonal, as long as wide; two pairs of eyes, without pigmentation; anterior pair on middle part, posterior pair near to posterior margin (Fig. 17A). Facial tubercle prominent, pointed. Median antenna with ceratophore long, inserted frontally, style long, expanded subdistally, tip filiform (slightly longer than laterals). Lateral antennae with ceratophores inserted terminally, styles thin, shorter than median antenna, similar in shape to median antenna (Fig. 17A). Palps with stout papillae, tapered, as long as median antenna. Pharynx missing (previously removed; 12 pairs of marginal papillae; jaws with smooth cutting edge). Tentacular segment not visible dorsally; tentaculophores long, thin, with chaetae; tentacular cirri similar in shape to antennae. Segment two dorsally projected on prostomium as a nuchal rounded lobe (Fig. 17A). Elytra with fringe of short papillae; surface granular with numerous microtubercles, and digitiform papillae (Fig. 17G). First pair of elytra with microtubercles and macrotubercles spherical or hemispherical, spinous (Figs 17B, C; 18A, F), larger in elytrophoral plug area (Fig. 18B). Elytra of median and posterior segments oval with fringe of slender papillae (Figs 17F; 18C, E), surface with numerous conical macrotubercles, amber incolour, sclerotized, basally spinous, tips long (Figs 17D, E; 18D, E, G, H), larger macrotubercles over elytrophoral plug area. Parapodia biramous, with branchial filaments laterally to eytrophores, cirrophores and between neuropodia. Notopodia shorter than neuropodia. Neuropodia with postchaetal rounded lobe, prechaetal lobe with a small acicular lobe, acicular tips slightly projected. Dorsal cirri short, thin, smooth, with subdistal swelling, tips filiform. Cirrophores short. Ventral cirri thin, short, tips filiform. Nephridial papillae from segment seven. Notochaetae abundant, long, slender, with minute rows of spines. Neurochaetae thicker than notochaetae; upper bundle with shorter chaetae, tips with subdistal spines. Pygidium with anal cirri long, similar to dorsal cirri, anus terminal in last segment. Remarks. The specific epithet given by Kinberg most probably refers to Queen Animata Pômare, who reigned in Tahiti from 1827 to 1877, an account of whom is given by O’Brien (2006). The type specimen is the only known record. The holotype of C. pomareae (Kinberg, 1856) is about half as long as the critical size indicated by Augener (1927), and herein confirmed; however, instead of having many globular macrotubercles densely packed, there are just a few, and they have very long, conical macrotubercles in the elytrophoral plug area. Consequently, we are confident about using the type, size, and density of globular macrotubercles as diagnostic features, and that C. pomareae differs from its congeners by having a low density of globular macrotubercles, and many conical macrotubercles. Type locality. Tahiti, French Polynesia (20°S, 150° W). Distribution. Only known from the locus typicus., Published as part of Salazar-Silva, Patricia, López-Sánchez, Daniel A. & Salazar-Vallejo, Sergio I., 2020, Revision of Chaetacanthus Seidler, 1922 (Annelida, Phyllodocida, Polynoidae), pp. 395-422 in Zootaxa 4885 (3) on pages 415-417, DOI: 10.11646/zootaxa.4885.3.5, http://zenodo.org/record/4296773, {"references":["Kinberg, J. G. H. (1856) Nya slagten och arter af Annelider. Ofversigt af Kongliga Vetenskaps-Akademiens Forhhandlingar Stockholm, 12 (9 - 10), 381 - 388.","Kinberg, J. G. H. (1858) Kongliga Svenska Fregatten Eugenies Resa omkring jorden under befal af C. A. Virgin aren 1851 - 1853. Zoologi, 1. Annulater. Almquist and Wicksells, Uppsala & Stockholm, 32 pp., 8 pls.","Seidler, H. J. (1924 (1923 )) Beitrage zur Kenntnis der Polynoiden, 1. Archiv f ̡ r Natugeschichte Berlin, 89 (11), 1 - 217. https: // doi. org / 10.1002 / mmnz. 4830110105","Hartman, O. (1948) The marine annelids erected by Kinberg with some notes on some other types in the Swedish State Museum. Arkiv for Zoologi, 42 A (1), 1 - 137.","O'Brien, P. (2006) ' Think of me as a woman': Queen Pomare of Tahiti and Anglo-French imperial contest in the 1840 s Pacific. Gender & History, 18, 108 - 129. https: // doi. org / 10.1111 / j. 1468 - 0424.2006.00417. x","Augener, H. (1927) Resultaten eener Reis van Dr. C. J. van der Horst in 1920: Polychaeten von Curacao. Bijdragen tot de Kennis der Fauna van Curacao. Bijdragen tot de Dierkunde, 25, 39 - 82. https: // doi. org / 10.1163 / 26660644 - 02501003"]}

Chaetacanthus harrisae n. sp. urn:lsid:zoobank.org:act: E304CEF1-D40F-404C-89D3-710D8087C618 Figure 9 Lepidonotus pomareae panamensis Hartman 1939a: 44–46, Pl. 6, Figs 70–77 (partim). Lepidonotus panamensis: Hartman 1948: 28 (n. status, partim). Type material. Pacific Panama. Holotype LACM 245-34, Pacora Island, Panama, 27–45 m, R/ V Velero III, Sta. 245-34, 07°44’19” N, 81°35’23”W, dredged off North West Point Rock, large shells and nullipores, 21 Jul. 1934. Diagnosis. Chaetacanthus with branchial filaments single, thick lobes; elytra with pale to brownish round spinous macrotubercles; microtubercles bulbous up to three times longer than wide, spinous surface extended along ½– 2 / 3 basal length; elytra without large, amber-colour macrotubercles arranged in honeycomb like groups. Description. Holotype (LACM 245-34) 5.5 cm long, 1.35 cm wide, 26 segments. Prostomium bilobed with facial tubercle prominent, acute. Two pairs of eyes, anterior pair on widest prostomial area, posterior pair hidden under anterior projection of second segment. Median antenna with ceratophore inserted frontally, style long, subdistally swollen. Lateral antennae with ceratophores inserted frontally, styles similar to median antennal one. Palps with rows of thick papillae. Pharynx not everted. Tentacular segment not visible dorsally. Tentaculophores thin, tentacular cirri similar to median antenna. Second segment with anterior border projected over prostomium as a short round nuchal lobe. Elytral margin with fringe of long abundant, filiform papillae (Fig. 9A), some with globular tips, including a distinctive bundle of papillae. Elytral surface verrucose with abundant globular, non-sclerotized spinous macrotubercles (Fig. 9G), and clavate micropapillae (Fig. 9B). First pair of elytra with scattered microtubercles along its whole surface, globular macrotubercles close to elytrophoral plug area (Fig. 9A, G). On middle and posterior elytra globular macrotubercles scarce (Fig. 9F), spinous surface extended along ½– 2 / 3 basal length, microtubercles numerous, bulbous with long peaks (Fig. 9 B–E). Parapodia biramous. Notopodia thick with acicular tips emergent. Neuropodia distally truncate, acicular tips emergent. Branchial filaments present between successive parapodia. Dorsal cirri thin, long, reaching neurochaetal tips, cirri subdistally swollen, resembling antennae. Cirrophores robust. Nephridial papillae long, thick. Notochaetae thin capillaries, long, with spinous surface, lower notochaetae shorter, slightly curved, serrated. Neurochaetae with upper region short, subdistally with long thin spines, tips entire, long, acute. Etymology. This species is named after Mrs. Leslie Harris, our long-term friend and teacher, in recognition of her efforts supporting taxonomy of polychaetes, and especially because she has been very generous by housing us during repetitive visits to Los Angeles during the last 20 years. Remarks. Hartman (1939a) described Lepidonotus pomareae panamensis and indicated its differences from the nominal form by having elytra “conspicuously covered with numerous large headed, high tubercles, the sixth pair of elytra is rectangular, not triangular, and the total length is over 35 mm as against 13 mm specified for L. pomareae.” As indicated below, the holotype of this subspecies, later raised to species level as L. panamensis, is regarded as a junior synonym of C. pilosus (Treadwell, 1937). However, the specimen investigated here belongs neither to L. pilosus nor to L. pomareae, and is described here as C. harrisae n. sp. The material was erroneously referred from station 254-34, but it comes from station 245-34. Further, C. harrisae n. sp. differs from C. pilosus because its elytra do not have pedunculated tubercles, in the first pair of elytra of C. harrisae the macrotubercles are mainly globular, scarce and concentrated along the area corresponding to the elytrophoral plug. In elytra of median and posterior segments, the macrotubercles are smaller, and the microtubercles bear long, tapered peaks. On the other hand, members of C. harrisae n. sp. also differ from members of C. pomareae (Kinberg, 1856) in that the latter lacks the long conical tubercles scattered along the posterior elytral half area, and only the anterior elytra have long macrotubercles. Type locality. Pacora Island, Panamá, in 27–90 m depth. Distribution. Only known from the original record.

Chaetacanthus brasiliensis (de Quatrefages, 1866) n. comb. Figures 1–6, 7, 8, 13 D–F Polynoe brasiliensis de Quatrefages, 1866: 246–247. Iphione magnifica Grube, 1876: 51. Polynoe branchiata Treadwell, 1901:186; Horst 1922: 197–198, Fig. 1. Lepidonotus (Physalidonotus) barbatus Augener 1910: 244–246, Figs 4–6. Lepidonotus (Physalidonotus) magnificus: Augener 1922: 40. Lepidonotus brasiliensis: Seidler 1924: 37 (n. comb.); Amaral & Nonato 1982: 25; de Assis et al. 2015: 65 (Tabl. 1), 68. Physalidonotus magnificus: Seidler 1921: 87 (n. comb.). Chaetacantus magnificus: Seidler 1922: 301; Seidler 1924: 97 (n. comb., syn.); Amaral & Nonato 1982: 18 –19, Figs 24–31; de Brito et al. 2013: 27–29, Figs 1–6. Euphione (Chaetacanthus) magnificus: Augener 1927: 43–44. Lepidonotus branchiatus Treadwell, 1939: 183–184, Fig. 16. Lepidonotus pilosus: Treadwell 1941: 26 (specimen not seen; non Treadwell, 1937). Type material. Brazil. Holotype of Polynoe brasiliensis de Quatrefages, 1866, MNHN 78, Bahía, 1868. Trinidad. Holotype of Iphione magnifica Grube, 1876, ZMB 1059, Schilling leg. (plus one slide made by Seidler). Puerto Rico. Holotype of Polynoe branchiata Treadwell, 1901, USNM 16006, Harbor Mayaguez, Bahía Boquerón, United States Fish Commission Steamer Fish Hawk, Sta. 6065, 8– 10 m, 20 Jan. 1899. Additional material. Brazil. UMML 4215, R/V Oregon, Cruise 84, Sta. 4215 (00°27’ N, 47º09’ W), 22 m, 26 Feb. 1963 [3.5 cm long, 1.2 cm wide, 26 segments]. Caribbean Panama. Four specimens (ECOSUR P3100), Bocas del Toro, Islote Manglar, off Isla Bastimento, 2 m, dead Agaricia coral, 2 m depth, 12 Jul. 2018, O. Molina, coll. [2.5–4.5 mm long, 0.7–1.5 mm wide (without chaetae), 26 segments; nephridial lobes from segment 7]. Diagnosis. Chaetacanthus with branchial filaments distally bifurcated; elytral surface with digitiform papillae and numerous spinous globular microtubercles from third pair of elytra with macrotubercles amber colour, sclerotized, depressed in honeycomb like groups; outer area with macrotubercles fusiform mucronate, marginal ones hemispherical; inner area with abundant, dark microtubercles conical with thick spines. Redescription. Holotype of Polynoe brasiliensis (MNHN 78) complete, dehydrated, 1.5 cm long (20–22 mm long in original description), 0.4 cm wide, 26 segments. Prostomium bilobed, facial tubercle rounded; median antenna with long ceratophore inserted frontally, style dried; lateral antennae inserted terminally with long thin ceratophores, styles dried-out; palps papillate; pharynx not everted. Tentacular segment not visible dorsally; segment two projected on prostomium as rounded lobe; tentaculophores thin with few thin chaetae. First pair of elytra circular, following ones oval, wide, imbricate, margins with long abundant fimbriae along posterolateral and external margins, and a bundle of long filiform papillae along inner posterolateral margin. Surface of two anterior elytra with hemispherical macrotubercles spinous over elytrophoral area arranged in a C-shaped row. Following elytra with macrotubercles ambercolour, depressed, densely packed in honeycomb like groups in elytral centre (Fig. 1A). Outer elytral region with macrotubercles covered by small spines (Fig. 1B, C), marginal ones hemispherical, other numerous fusiform with sharp tips, surface spinulose (Fig. 1D), markedly larger along posterolateral external area, inner elytral area with abundant microtubercles, conical spinous (Fig. 1D). Parapodia biramous. Notopodia short with abundant notochaetae; neuropodia thick, truncate, with a short acicular projection. Branchial filaments along notopodial anterior and posterior surfaces. Cirrigerous segments with dorsal cirri thin, subdistally swollen, tips long filiform. Ventral cirri thick, short. Notochaetae thin, brownish, shorter than neurochaetae, surface spinulous, tips sharp. Neurochaetae markedly thicker, amber, short, tips unidentate, slightly falcate, with a few subdistal thick spines and striae (Fig. 1 E–G). Segment 2 with neurochaetae markedly thinner, with several rows of long spines. Variation. The holotype of Iphione magnifica Grube, 1876 (ZMB 1059), and the holotype of Polynoe branchiata Treadwell, 1901 (USNM 16006) have the same diagnostic features for prostomia, elytra, and parapodia, with the sole exception that the former does not have its median antenna. Anterior eyes on the widest prostomial area; posterior eyes partially hidden by nuchal lobe (Figs 2B; 3B; 4A; 6B). Elytra with fringe of long papillae (Figs 2C; 3C; 5; 12 A–C); spinous globular macrotubercles on first elytra (Figs 2C, D; 3B, F; 4B); from the third pair of elytra macrotubercles are sclerotized, depressed, packed in honeycomb groups (Figs 2A, E; 3D; 4D; 6A), with conical microtubercles (Fig. 3G, H), and fusiform macrotubercles with acute tips (Figs 3E; 5C). Parapodia with branchial filaments (Figs 3H; 5D; 6A), and neurochaetae with tips unidentate (Figs 3I; 5E; 6C). These features are also present in the additional material (UMML 078). Antennae, tentacular and dorsal cirri thin, smooth, subdistally swollen, tips filiform; median antenna longer than prostomium; lateral antennae half as long as prostomium, palps papillated; pygidium thick, long, anal cirri resembling dorsal cirri, subdistally swollen, tips filiform. Elytral ornamentation has been indicated above; the colour of the neurochaetae can vary from light brownish to dark, and the notochaetae are slender and long. Augener (1927: 44) noted that the elytra of the C. brasiliensis specimens (as Euphione (Chaetacanthus) magnificus) smaller than 20 mm in length do not show the honeycomb like patch of large macrotubercles. He further added that Treadwell (1901) specimens of P. branchiata were 20–25 mm long, and that because of their small size these patches of elytral macrotubercles were barely developed. In our new material, elytral shape and ornamentation change along the body. The first elytra are almost circular (Fig. 7A); the subsequent ones are elongated, almost oval, medially narrower, and wider laterally, inserted obliquely and imbricate, posterior and lateral margins with fringe. In first and second pair of elytra, the macrotubercles start as an irregular, oblique row (Fig. 7A), often with a bent section, resembling a “C”, “J” or half-moon shaped, and there are other large globular macrotubercles along the margin. By segment 9, the macrotubercles are arranged as an ovoid group with individual round and larger macrotubercles (Fig. 7B), and the group expands laterally covering about one-fourth of elytral surface (Fig. 7C). Elytra of posterior segments show two modifications because macrotubercles become larger although the covered elytral surface is about the same (Fig. 7D). Other large macrotubercles are fusiform, truncate basally, distally mucronate, abundant on the outer lateral surface. On the internal elytral areas, the conical spinous microtubercles can be dark. Fimbriae are well-developed along most elytral margins, often loaded with foreign materials, and form a distinct bundle in the inner, posterior elytral region, although they can be eroded by excessive brushing off. The honeycomb-like group of macrotubercles varies with body size as noted by comparing C. brasiliensis specimens of different size (2.5 cm long vs. 3.5 cm long). The first elytra shows that whereas in smaller specimens (Fig. 8A) the central macrotubercles are arranged into a row barely turned around, in larger specimens (Fig. 8D), the row turns around quite distinctly resembling an inverted “J”. As indicated above, by segment 9 in smaller specimens the macrotubercles are round, smaller (Fig. 8B) than those present in larger specimens (Fig. 8E), where they are also polygonal instead of round. In posterior segments, the smaller specimens have more macrotubercles but they are less pigmented, and the group extends over a slightly smaller elytral surface (Fig. 8C), whereas in larger specimens, the macrotubercles are larger, darker, and extended over a larger area (Fig. 8F). Remarks. Polynoe brasiliensis de Quatrefages, 1866 is newly combined into Chaetacanthus Seidler, 1922 as C. brasiliensis (de Quatrefages, 1866). The original description was based upon a single specimen, hence the holotype, although its type status was regarded as syntype (Solís-Weiss et al. 2004: S14). Despite the fact that the original description of P. brasiliensis does not include illustrations, and that the holotype is dehydrated, it is a complete specimen and some diagnostic features were observed: elytral surfaces, and the presence of branchiae are visible between parapodia, close to cirrophores. These features match the diagnosis of Chaetacantus and it explains the new combination. The presence of branchial filaments was overlooked by de Quatrefages (1866), and Seidler (1924) only translated the original description, but the latter transferred the species and newly combined it into Lepidonotus. In that combination, it has been reported in a faunistic note and in a compilation (Amaral & Nonato 1982, de Assis et al. 2015). The study of the holotype of Polynoe branchiata Treadwell, 1901 from Puerto Rico, indicated that this species is a junior synonym of C. magnificus as well, as already indicated by Seidler (1924: 97), Augener (1927: 43), and Hartman (1959: 99). We confirm this synonymy, but the senior species name is C. brasiliensis (see below). For instance, the publication date for the paper by Treadwell on Puerto Rican polychaetes has been cited as 1900, 1901, or 1902; however, the correct publication date is 4 October 1901 (Evermann 1902). Chaetacanthus brasiliensis and C. magnificus refer to a rare biological entity. It is rarely collected and most collections have just a few specimens, if any at all, with the sole exception of Augener (1927) who reported 30 specimens. Consequently, there are several publications using C. magnificus, and a few ones listing P. brasiliensis. This could make us propose a reversal of precedence and retain the junior synonym instead of the senior one, following article 23.9 of the code (ICZN 1999). This means that because the senior species-group name has been used less frequently than the junior one, the older name should be regarded as a nomen oblitum, and the other more frequently used, nomen protectum. Nevertheless, this violates two essential conditions in 23.9.1.1 and 23.9.1.2 of the Code, because the senior synonym has been used as a valid name after 1899, and the junior synonym has not been used in at least 25 works published by 10 different authors during the last 50 years. Consequently, there is no need to reverse precedence, and we newly combine it as C. brasiliensis, and confirm it as the senior synonym over C. magnificus (Grube, 1876). As explained by Seidler (1924), and herein confirmed, the type specimen of Iphione magnifica Grube, 1876 lacks the median antenna, which probably caused Grube to place it in Iphione Kinberg, 1856. Despite the fact of this missing appendage, and a superficial similarity in elytral appeareance, the species does not match with Iphione, and it is why Seidler (1924) proposed it as the type species for his new genus Chaetacanthus. Members of C. brasiliensis resemble C. ornatus n. sp. because their elytra have large macrotubercles in honeycomb-like groups, and a comparison of specimens of similar size indicate some differences (Fig. 13). In C. brasiliensis macrotubercles are smaller, usually polygonal, and extend over smaller elytral areas (Fig. 13 D–F) than in C. ornatus n. sp. whose macrotubercles are usually larger, globular, and extended over larger elytral areas (Fig. 13 A–C). On the other hand, Puerto Rican specimens were recorded with ripe oocytes in November (Allen 1957). Lepidonotus pilosus Treadwell, 1937, described from Western Mexico, was also regarded as a junior synonym of C. magnificus by Hartman (1939a: 29; 1956: 253), and by de Brito et al. (2013). However, this is a different species (see below), and it is herein redescribed. On the other hand, Lepidonotus brasiliensis laevis Rullier & Amoreux, 1979 was described with two specimens dredged about 300 km E off Mar del Plata in sediments between 220–270 m depth. The description was restricted to details of elytra and chaetae, and provided illustrations for them. Elytra has large champagne cork-, or mushroom-shaped macrotubercles with finely spinous heads, and long marginal fimbriae; neurochaetae were described and illustrated as blackish, smooth, unidentate. The subspecies was retained in Lepidonotus by de Assis et al. (2015), but its neurochaetae differ from those present in members of this genus and, after this feature, the subspecies does not belong in this genus. Regretfully, branchial filaments were not indicated in the original description, but after Fauchald (1977) key to genera, there would be only two options for transferring this subspecies after the presence of smooth neurochaetae: Euphionella Monro, 1936 if it has branchial filaments, Dilepidonotus Hartman, 1967 if they are missing. For the former, the most similar species might be E. besnardi Amaral & Nonato, 1982 dredged in muddy sands off Rio Grande do Sul, in 200 m depth. For the latter, the only known species, D. falklandicus Hartman, 1967 has blackish unidentate neurochaetae, but macrotubercles are sparser and markedly smaller. Nevertheless, despite Rullier & Amoureux (1979: 152) indicated the type was deposited in the Paris museum (AK 229), it was not included in the type catalogue (Solís-Weiss et al. 2004). In conclusion, L. brasiliensis laevis does not belong in Lepidonotus nor Chaetacanthus by having smooth neurochaetae; its generic affiliation cannot be solved until the type material is found, or some topotypes are found and carefully compared. This is beyond our current objectives. Type locality. Bahia, Brazil. Distribution. Puerto Rico to Panamá, Curaçao, Trinidad, Bahia and Paraíba, Brazil.

Key to species of Chaetacanthus Seidler, 1924 1 Elytra of middle and posterior segments with large, amber macrotubercles packed in a sclerotized honeycomb group...... 2 – Elytra of middle and posterior segments without honeycomb group amber macrotubercles........................... 3 2(1) Prostomial anterior eyes area bulky; sclerotized macrotubercles of honeycomb group globular, surface with minute spines; macrotubercles of outer area blunt, fusiform, without acute mucrons.................... C. ornatus n. sp. Eastern Pacific – Prostomial anterior eyes area non-bulky laterally; sclerotized macrotubercles like honeycomb depressed, surface without minute spines; macrotubercles of outer area fusiform, with acute mucrons................................................................... C. brasiliensis (de Quatrefages, 1866) n. comb. Grand Caribbean to Ubatuba, S„o Paulo, Brazil 3(1) Branchial filaments single, thick lobes..................................................................... 4 – Branchial filaments bifurcated; elytra with pedunculated microtubercles and macrotubercles hemispherical............................................................................... C. pilosus (Treadwell, 1937) Eastern Pacific 4(3) Elytra of middle and posterior segments with conical macrotubercles (up to five times longer than wide, basally spinous, long tip); microtubercles round and spinous............................ C. pomareae (Kinberg, 1856) South Central Pacific – Elytra of middle and posterior segments with globular macrotubercles; microtubercles globular with long tips...................................................................................... C. harrisae n. sp. Eastern Pacific, Published as part of Salazar-Silva, Patricia, López-Sánchez, Daniel A. & Salazar-Vallejo, Sergio I., 2020, Revision of Chaetacanthus Seidler, 1922 (Annelida, Phyllodocida, Polynoidae), pp. 395-422 in Zootaxa 4885 (3) on page 417, DOI: 10.11646/zootaxa.4885.3.5, http://zenodo.org/record/4296773, {"references":["Seidler, H. J. (1924 (1923 )) Beitrage zur Kenntnis der Polynoiden, 1. Archiv f ̡ r Natugeschichte Berlin, 89 (11), 1 - 217. https: // doi. org / 10.1002 / mmnz. 4830110105","de Quatrefages, A. (1866 (1865 )) Histoire Naturelle des Anneles marines et d'Eau Douce: Annelides et gephyriens. Vol. 1. Roret, Paris, 578 pp. https: // doi. org / 10.5962 / bhl. title. 122818","Treadwell, A. L. (1937) The Templeton Crocker Expedition, 8. Polychaetous annelids from the West coast of Lower California, the Gulf of California and Clarion Island. Zoologica, Scientific Contributions of the New York Zoological Society, 22, 139 - 159, Pls 1 - 2.","Kinberg, J. G. H. (1856) Nya slagten och arter af Annelider. Ofversigt af Kongliga Vetenskaps-Akademiens Forhhandlingar Stockholm, 12 (9 - 10), 381 - 388."]}

Chaetacanthus pilosus (Treadwell, 1937) Figures 14–16 Lepidonotus pilosus Treadwell, 1937: 141–143, Pl. 1, Figs. 1–7. Lepidonotus pomareae panamensis Hartman, 1939a: 44–46, Pl. 6, Figs. 70–77 (partim). Lepidonotus panamensis: Hartman 1948: 28 (n. status, partim). Chaetacanthus magnificus: Salazar-Vallejo et al. 1990: 215, Fig. 37 (non Grube, 1876). Chaetacanthus pilosus: Salazar-Silva 2006: 146 (reinst.). Type material. Eastern Pacific. Holotype of Lepidonotus pilosus Treadwell, 1937, AMNH 3531, Arena Bank, Gulf of California, Sta. 136, D-13 (23°29’ N 109° 24’ W), 20 Apr. 1936. Holotype of Lepidonotus pomareae panamensis Hartman, 1939a, LACM 3, AHF-5, Poly 0039, Bahía Honda, Panama, off North Island, R / V Velero III, Sta. 863- 38, 54–90 m, 1 Mar.1938. Additional material. Eastern Pacific, Panama. One specimen, LACM 863-38, off Bahía Honda, 54–90 m, rock sand mud, R/ V Velero, Sta. 863-38, 07°45’35” N, 81°35’35” W, 26 Jan. 1939, identified as Lepidonotus pomareae panamensis but separated from holotype. Diagnosis. Chaetacanthus with branchial filaments digitiform, bifurcated; elytra with abundant pedunculated macrotubercles and microtubercles, spinous, hemispherical, amber in colour, larger over the elytrophore and on first pair of elytra. Description. Holotype of Lepidonotus pilosus (AMNH 3531) robust, 2.5 cm long, 1.3 cm wide, 26 segments; body homogeneously yellowish without spots, integument wrinkled. Prostomium longer than wide, slightly retracted into segment two; prostomial lobes laterally expanded. Two pairs of eyes, circular, dark, anterior pair on widest prostomial area, posterior pair hidden under anterior projection of segment two (Fig. 14A). Facial tubercle long, slender. Median antenna with ceratophore thick, long, inserted frontally, at same level of lateral antennae, style missing. Lateral antennae with ceratophores thick, long, inserted frontally on prostomial lobes, styles missing. Palps robust, long, two times longer than prostomial length, tapered into filiform tips, surface with rows of papillae. Pharynx not everted. Tentacular segment not visible dorsally. Tentaculophores thick, long, inserted laterally to prostomium, with several chaetae; tentacular cirri missing. Second segment projected anteriorly over prostomium as a wide round lobe. First pair of elytrophores expanded laterally over tentaculophores, with large elytral scar. Segment three narrower than following ones. Elytral margin with fringe of abundant long papillae (Fig. 14B), all with a distinctive bundle of papillae on posterior margin. Elytral surface with abundant spinous macrotubercles, and microtubercles. Macrotubercles pedunculate, distally hemispherical with abundant small spines, mostly scattered along elytral surface, but in first pair of elytra macrotubercles prominent, concentrated in elytral plug area (Fig. 14C, D). Microtubercles hemispherical or tapered, tips subconical. Parapodia biramous, robust. Notopodia short. Neuropodia short, truncated, with acicular tips emergent (Fig. 14E, F). Notopodia with abundant brachial filaments (Fig. 14F), dorsally and laterally, each filament swollen, appearing septate, tips bifurcate. Dorsal cirri thin, long, slightly clavate, tips filiform. Cirrophores bulbous basally, elongate; elytrophores wide with large elytral scars. Ventral cirri short, not reaching neuropodial tips. Nephridial papillae thick, long. Notochaetae abundant, thin, spinous capillaries, thinner and shorter than neurochaetae (Fig. 14E, F). Neurochaetae thick, dark amber (Fig. 14F), upper fascicle with shorter chaetae with long entire tips, lower ones curved, subdistally with short spines. Remarks. Although Hartman (1939a) did not examine the type material of L. pilosus, she correctly regarded it as belonging to Chaetacantus but as a junior synonym of C. magnificus (Grube, 1876). Type material of both species was examined. Treadwell (1937) described and illustrated the type of L. pilosus indicating it has parapodial branchial filaments, and this confirms its belonging into Chaetacanthus. However, C. pilosus differs from C. magnificus (Grube, 1876), herein synonymized with C. brasiliensis (de Quatrefages, 1866). The main difference is that the elytra of C. pilosus do not have the prominent patch of sclerotized, amber macrotubercles arranged in honeycomb like patches, because of this difference C. pilosus is redescribed. The nominal species, Lepidonotus pomareae, and the subspecies, L. p. panamensis, both have branchial filaments between successive parapodia (Fig. 16F). However, because the features of L. pomarae panamensis are the same as those shown by C. pilosus in prostomium (Fig. 16A), elytral ornamentation (Figs 15 A–D; 16B–E), notochaetae and neurochaetae (Fig. 16G, H), the subspecies deserved to be raised in status as a full species, as correctly indicated by Hartman (1948) as C. panamensis (Hartman, 1939). Nevertheless, this species shares the same morphological pattern with C. pilosus (Treadwell, 1937) and it is herein regarded as a junior synonym of the latter. Furthermore, it is interesting to note that in the USNM in Washington (USNM 47981), there is another specimen incorrectly labeled as the holotype of Lepidonotus panamensis Hartman, 1939, collected in Honda Bay, near Coiba Island (R/V Velero III, Sta. 861-38). Hartman (1939: 44) included three specimens for her Lepidonotus pomareae panamensis, two from Station 863-38, and one from station 254-34, with no specimen from any other locality (station 861-38). Consequently, that additional USNM specimen cannot be the holotype (ICZN 1999, Art. 73.1). It must be indicated that in C. pomareae (Kinberg, 1856), elytra of median segments only have bulbous microtubercles with thick tips, whereas in posterior elytra the prominent conical macrotubercles are basally spinous with long, smooth tips (see below), and these macrotubercles are not present in C. pilosus. Type locality. Arena Bank (23°29’ N, 109°24’ W), Gulf of California. Distribution. Gulf of California and Bahía Honda, Panama., Published as part of Salazar-Silva, Patricia, López-Sánchez, Daniel A. & Salazar-Vallejo, Sergio I., 2020, Revision of Chaetacanthus Seidler, 1922 (Annelida, Phyllodocida, Polynoidae), pp. 395-422 in Zootaxa 4885 (3) on pages 411-414, DOI: 10.11646/zootaxa.4885.3.5, http://zenodo.org/record/4296773, {"references":["Treadwell, A. L. (1937) The Templeton Crocker Expedition, 8. Polychaetous annelids from the West coast of Lower California, the Gulf of California and Clarion Island. Zoologica, Scientific Contributions of the New York Zoological Society, 22, 139 - 159, Pls 1 - 2.","Hartman, O. (1939 a) Polychaetous annelids, 1. Aphroditidae to Pisionidae. Allan Hancock Pacific Expeditions, 7, 1 - 156, pls. 1 - 28.","Hartman, O. (1948) The marine annelids erected by Kinberg with some notes on some other types in the Swedish State Museum. Arkiv for Zoologi, 42 A (1), 1 - 137.","Salazar-Vallejo, S. I., de Leon-Gonzalez, J. A. & Chavez-Comparan, J. C. (1990) Poliquetos (Annelida: Polychaeta) de la Bahia de Manzanillo, con una clave ilustrada para las especies de Colima, Mexico. Revista de Biologia Tropical, 38, 211 - 229.","Grube, A. E. (1876) Bemerkungen ʾ ber die Familie der Aphroditeen (Gruppe Polyonina, Acoetea, Polylepidea). Jahres-Bericht der Schlesischen Gesellschaft f ̡ r vaterlandische Cultur, 1875, 46 - 72.","Salazar-Silva, P. (2006) Scaleworms (Polychaeta: Polynoidae) from the Mexican Pacific and some other Eastern Pacific sites. Investigaciones Marinas, Valparaiso, 34 (2), 143 - 161. https: // doi. org / 10.4067 / S 0717 - 71782006000200014","de Quatrefages, A. (1866 (1865 )) Histoire Naturelle des Anneles marines et d'Eau Douce: Annelides et gephyriens. Vol. 1. Roret, Paris, 578 pp. https: // doi. org / 10.5962 / bhl. title. 122818","Kinberg, J. G. H. (1856) Nya slagten och arter af Annelider. Ofversigt af Kongliga Vetenskaps-Akademiens Forhhandlingar Stockholm, 12 (9 - 10), 381 - 388."]}

Chaetacanthus ornatus n. sp. urn:lsid:zoobank.org:act: 8D720EB8-0DEE-4090-816F-1B22BDF989C3 Figures 10–12, 13 A–C Chaetacanthus magnificus: Monro 1928: 558; Hartman 1939a: 28–29 (non Grube, 1876). Chaetacanthus cf. magnificus: Hernández-Moreno 2011: 28–32, Fig. 9 A–O, Pls. 5D, 6F (non Grube, 1876). Type material. Eastern Pacific. Holotype ECOSUR 233, Puerto Escondido, Oaxaca, México, 10, associated with algae on thorny bivalve (Spondylus Sowerby, 1847), 4 Jul. 2004, S. García, coll. Diagnosis. Chaetacanthus with branchial filament digitiform with septate appearance; anterior eyes area bulky; elytral macrotubercles globular, amber-colour, sclerotized in large honeycomb like groups, outer area with fusiform macrotubercles distally blunt; numerous microtubercles dark, conical with thick spines on overlapping medially area. Description. Holotype (ECOSUR 233) 2.9 cm long, 1.1 cm wide, 26 segments (Fig. 10A). Prostomium bilobed, facial tubercle small, round. Two pairs of dark eyes; anterior pair on widest prostomial bulky area; posterior pair near posterior prostomial margin; posterior eyes much smaller than anterior ones (Fig. 10B). Median antenna with thick, long ceratophore inserted frontally between prostomial lobes, style long, 1.5 times longer than prostomial length, thick, subdistally clavate, tip filiform, surface smooth, with pigmentation rings medially and subdistally. Lateral antennae with ceratophores inserted terminally on frontal prostomial border, brownish, styles similar in shape and pigmentation to median antenna. Palps robust, dark, taper into thin tips, surface with long rows of papillae. Pharynx everted with soft marginal papillae, 12 dorsally and 13 ventrally (Figs 10A, B; 11A, B). Tentacular segment not visible dorsally. Tentaculophores basally thick, inserted laterally to prostomium. Tentacular cirri with similar shape and pigmentation as median antenna. Segment two projected anteriorly over prostomium as a small round lobe (Fig. 10B). First pair of elytrophores long, not covering tentaculophores. Segment three narrower than successive segments. All elytra with fringe of abundant, long papillae, and a bundle of long papillae in posterior inner margin (Fig. 12 A–D). First pair of elytra with abundant hemispherical microtubercles along its surface, each with surface spinulose; globular macrotubercles arranged in a curved J-shaped row, smaller along posterior border (Fig. 12A) some pedunculated. From third segment, elytra bear globular macrotubercles with minute spines, mainly along posterior border, and sclerotized on central area forming a honeycomb patch (Fig. 12 B–D). Towards dorsal midline, each elytron has dark microtubercles conical with thick peaks; fusiform macrotubercles long, thin, with short spines along their surface; along outer region numerous fusiform macrotubercles distally rounded. Parapodia biramous; branchial filaments digitate, abundant, some appearing septate (Fig. 10C). Notopodia short with acicular tips emerging. Neuropodia distally truncate, acicular tips slightly projected. Elytrophores wide, dorsal tubercles inconspicuous. Dorsal cirri short, not reaching neurochaetal tips, distally clavate with cirrophores short, swollen. Ventral cirri thick, short with filiform tips. Nephridial papillae present from segment 11, cylindrical, long. Pygidium with two anal cirri, similar to dorsal cirri. Notochaetae abundant, thin, short, as long as half neurochaetal length, tips filiform, surface with rows of denticles (Fig. 10C). Neurochaetae dark amber (Fig. 10C), thick, slightly curved, slender along first two segments (Fig. 10C, inset), markedly larger and thicker thereafter; median segments with upper bundle with shorter chaetae, subdistally with scarce spines, tips entire. Variation. Elytral variation will be better understood in a comparison between C. ornatus n. sp. and C. brasiliensis. Chaetacanthus ornatus has swollen macrotubercles and larger honeycomb-like groups than those present in C. brasiliensis. In first elytra, C. ornatus macrotubercles are about twice as large and mostly arranged in a single row (Fig. 13A), whereas in C. brasiliensis they are smaller, arranged in a row with 1–2 macrotubercles (Fig. 13D). By segment 9 in C. ornatus, the honeycomb groups are 3–4 times larger and occupy about ¼ elytral surface (Fig. 13B), whereas in C. brasiliensis they extend for about 1 / 6 of elytral surface and macrotubercles are smaller (Fig. 13E). In segment 24, the individual macrotubercles in C. ornatus have enlarged about 3–4 times more than in segment 9, and now they extend for about 1 / 3 elytral surface (Fig. 13C), whereas in C. brasiliensis the macrotubercles have doubled their size and expanded over elytra such that now they occupy about ¼ elytral surface (Fig. 13F). Etymology. The specific epithet is derived from the Latin word ornatus (masculine), meaning furnished, equipped, adorned, or decorated, in reference to the large honeycomb group of macrotubercles on elytral surfaces. Remarks. Members of Chaetacanthus ornatus n. sp. were compared with the type material of C. brasiliensis; C. ornatus n. sp. differs because its dorsal cirri are short, the facial tubercle is short and round, not elongate. The globular tubercles present on first pair of elytra are similar in shape to those of middle and posterior elytra; each is globular with spinous surface. Further, C. ornatus differs from C brasiliensis because the macrotubercles of the central patch are not depressed and the patch is wider, covering a region larger than the elytrophoral plug. The long fusiform tubercles are distally blunt, without a sharp tip, and the microtubercles along the inner surface have thicker peaks. Monro (1928) recorded C. magnificus from Coiba and Gorgona Islands, in the Eastern Pacific, and indicated his accounts were the first records for the Caribbean species into the Pacific Ocean. Monro materials were not examined, but they are regarded as conspecific with C. ornatus . Hartman (1939a) recorded C. magnificus for the Pacific with specimens from Ecuador, Panamá and México, The specimens from Socorro Island, Colima (sta. 132-34), and from Petatlan Bay, Guerrero (sta. 264-34) require corroboration, but might also belong to this new species. Type locality. Puerto Escondido, Oaxaca, México. Distribution. Puerto Escondido, Oaxaca, México; probably also present in Coiba, Panama; Isla Gorgona, Colombia.

The polynoid genus Chaetacanthus Seidler, 1922 currently includes three nominal species provided with parapodial branchiae. Members of this taxon have palps with longitudinal rows of papillae, notochaetae abundant and neurochaetae spinulose. Most Chaetacanthus species were originally described as belonging to Lepidonotus Leach, 1816, and some of them were later regarded as subjective synonyms of Iphione magnifica Grube, 1876, the type species for Chaetacanthus. This species was described from the Caribbean Sea and later recorded for the tropical Eastern Pacific. After the supposed Amphi-American distribution, a revision of all available material was performed in order to clarify the generic delineation, and to improve the understanding of species systematics. Further, some non-type specimens collected in Panama allowed us to have a better understanding of the variation of elytral shape and ornamentation along the body. The type material of Polynoe brasiliensis de Quatrefages, 1866 was examined and despite its poor condition, it shows parapodial branchial filaments which were overlooked in the original description; these branchiae are also present in the holotype of I. magnifica. We identify that there are no relevant difference between both species, and they are regarded as synonyms, and Chaetacanthus brasiliensis (de Quatrefages, 1866) is newly combined and is the senior synonym. On the other hand, Chaetacanthus pilosus (Treadwell, 1937), from the Eastern Pacific, and C. pomareae (Kinberg, 1856) from the South Central Pacific are redescribed, and C. harrisae n. sp., and C. ornatus n. sp. are both newly described from the Eastern Pacific. A key to identify all species of Chaetacanthus of the World, together with an appendix for the reversal of precedence of Lepidonotus Leach, 1816 over Eumolpe Oken, 1807 are also included.

Polynoidae Kinberg, 1856 has five branchiate genera: Branchipolynoe Pettibone, 1984, Branchinotogluma Pettibone, 1985, Branchiplicatus Pettibone, 1985, Peinaleopolynoe Desbruyères & Laubier, 1988, and Thermopolynoe Miura, 1994, all native to deep-sea, chemosynthetic-based habitats. Of these, Peinaleopolynoe has two accepted species; Peinaleopolynoe sillardi Desbruyères & Laubier, 1988 (Atlantic Ocean) and Peinaleopolynoe santacatalina Pettibone, 1993 (East Pacific Ocean). The goal of this study was to assess the phylogenetic position of Peinaleopolynoe, utilizing DNA sequences from a broad sampling of deep-sea polynoids. Representatives from all five branchiate genera were included, several species of which were sampled from near the type localities; Branchinotogluma sandersi Pettibone, 1985 from the Galápagos Rift (E/V “Nautilus”); Peinaleopolynoe sillardi from organic remains in the Atlantic Ocean; Peinaleopolynoe santacatalina from a whalefall off southern California (R/V “Western Flyer”) and Thermopolynoe branchiata Miura, 1994 from Lau Back-Arc Basin in the western Pacific (R/V “Melville”). Phylogenetic analyses were conducted using mitochondrial (COI, 16S rRNA, and CytB) and nuclear (18S rRNA, 28S rRNA, and H3) genes. The analyses revealed four new Peinaleopolynoe species from the Pacific Ocean that are formally described here: Peinaleopolynoe orphanae Hatch & Rouse, sp. nov., type locality Pescadero Basin in the Gulf of California, Mexico (R/V “Western Flyer”); Peinaleopolynoe elvisi Hatch & Rouse, sp. nov. and Peinaleopolynoe goffrediae Hatch & Rouse, sp. nov., both with a type locality in Monterey Canyon off California (R/V “Western Flyer”) and Peinaleopolynoe mineoi Hatch & Rouse, sp. nov. from Costa Rica methane seeps (R/V “Falkor”). In addition to DNA sequence data, the monophyly of Peinaleopolynoe is supported by the presence of ventral papillae on segments 12–15. The results also demonstrated the paraphyly of Branchinotogluma and Lepidonotopodium Pettibone, 1983 and taxonomic revision of these genera is required. We apply the subfamily name Lepidonotopodinae Pettibone 1983, for the clade comprised of Branchipolynoe, Branchinotogluma, Bathykurila, Branchiplicatus, Lepidonotopodium, Levensteiniella Pettibone, 1985, Thermopolynoe, and Peinaleopolynoe.

HODOR GEN. NOV. Type species: Hodor hodor gen. nov., sp. nov.

YODANOE GEN. NOV. Type species: Yodanoe desbruyeresi gen. nov., sp. nov., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on page 619

BATHYNOTALIA LEVENSTEIN, 1982 A Type species: Bathynotalia perplexa Levenstein,1982a. The genus is monotypic. Bathynotalia perplexa was originally classified as Macellicephalinae, but Pettibone (1985c, d, 1989c) referred to it as Polynoinae based on the figure of the prostomium having lateral antennae. We followed the interpretation of Pettibone because the description in Russian was not available. However, the specimens should be re-examined to confirm the classification., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on page 625, {"references":["Levenstein RYA. 1982 a. New genera of the subfamily Macellicephalinae (Polychaeta, Polynoidae) from the Tasman Hollow. Zoologicheskii Zhurnal 61: 1291 - 1296.","Pettibone MH. 1985 c. New genera and species of deep sea Macellicephalinae and Harmothoinae Galapagos and Western Mexico at 21 ° N and from the Santa Catalina channel. Proceedings of the Biological Society of Washington 98: 740 - 757."]}

POLARUSCHAKOV LAMELLAE SP. NOV. (FIG. 18A–G; TABLES 1, 2, 5) Polychaeta sp. EBS12o-Po143 (GenBank KJ736547) Janssen et al. (2015). Type material: Holotype, MNHN-IA-TYPE 1837 (IFR151), complete, length 8.41 mm, width 1.40 mm, 22 segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, BGR license area, station 59, collected 28 March 2015, epibenthic sledge supra-net, start 11°48.201′N, 117°30.500′W, end 11°48.442′N, 117°29.395′W, 4384– 4307 m depth, 2469 m trawling distance. Paratype 1, MNHN-IA-TYPE 1838 (IFR659-1 - 1), complete, length 3.40 mm, width 0.58 mm, 17 segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, APEI#3, station 192, collected 21 April 2015, epibenthic sledge epi-net, start 18°44.807′N, 128°21.874′W, end 18°45.338′N, 128°20.418′W, 4821– 4820 m depth, 2799 m trawling distance. Paratype 2, MNHN-IA-TYPE 1839 (IFR607), incomplete, length 2.06 mm, width 0.67 mm, ten segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, APEI#3, station 192, collected 21 April 2015, epibenthic sledge supra-net, start 18°44.807′N, 128°21.874′W, end 18°45.338′N, 128°20.418′W, 4821– 4820 m depth, 2799 m trawling distance. Description (based on holotype): Holotype complete, 8.42 mm long and 1.40 mm wide for 22 segments (including tentacular segment), dorsoventrally flattened, posteriorly tapering; live specimen slightly translucent, bluish (Fig. 18A); ethanol-preserved specimen pale white; chaetae golden. Prostomium bilobed, wider than long, lobes not developed anteriorly, short, rounded anteriorly, with an abrupt depression connecting to superior lip (Fig. 18A, B); frontal filaments absent; median notch between prostomial lobes narrow and shallow; eyes absent; a pair of internal white ganglia visible through translucent epidermis (difficult to see). Median and lateral antennae absent. Palps smooth, tapering, thin, short (reaching to segment 3; Fig. 18A, B). Tentacular segment fused to prostomium, with a pair of short lobes, inserted laterally and slightly ventral to prostomium; without acicula or chaetae; tentaculophores prominent, cylindrical, dorsal longer than ventral; dorsal tentacular style smooth, tapering, thin, short (reaching segment 4; Fig. 18B); ventral tentacular style missing. Pharynx not everted on holotype; dissected in paratype (MNHN-IA-TYPE 1838), with pharyngeal papillae not possible to count, two pairs of jaws, each one with one main fang, outer margin with a small, secondary tooth (small elevation; Fig. 18C). Second segment with elytrophores, subbiramous parapodia, with chaetae and ventral cirri. Ten pairs of large (largest in anterior segments), spherical elytrophores, present on segments 2, 4, 5, 7, 9, 11, 13, 15, 17 and 19 (all elytra missing). Cirrigerous segments with prominent dorsal cirrophores (largest in anterior segments); styles smooth, tapering, long (longer than tip of neuroacicular lobe; Fig. 18D); on segment 3 longer than on subsequent segments; dorsal tubercles present, rounded on segment 2, lamelliform on subsequent segments (Fig. 18D), decreasing in size posteriorly, largest on segment 8, inconspicuous on segment 18 (in paratypes, dorsal tubercles not seen). Segment 6 with a pair of flattened scale-like structures present (Fig. 18B); inserted before cirrophore, basally inflated, rounded; distally lamelliform, small, not reaching mid-dorsal line. Ventral cirri smooth, tapering, present from segment 2 to last segment; inserted basally on neuropodia of segment 2, style long (much longer than tip of neuroacicular lobe); in subsequent segments inserted medially on neuropodia (Fig. 18D), style short (shorter than tip of neuroacicular lobe). Parapodia subbiramous, notopodia reduced, much shorter than neuropodia (Fig. 18D). Notopodia reduced, narrow, subtriangular, tapering into long acicular lobe, tip of notoacicula not penetrating epidermis. Neuropodia large, rectangular to subtriangular, tapering into long acicular lobe, tip of neuroacicula not penetrating epidermis; post-chaetal lobe oval, slightly enlarged. Notochaetae very few (three observed), short, slender, slightly curved, with distinct spinous rows on convex side, with blunt tips (Fig. 18E); notochaetae more slender than neurochaetae. Neurochaetae moderate in number (26 observed), long, distally flattened to concave, serrated along both margins, with blunt tips (Fig. 18F); lower neurochaetae shorter, with pointed tips (Fig. 18G), shorter than upper or middle groups. Nephridial papillae absent. Pygidium rounded, not enclosed by last segment; with terminal anus (Fig. 18A). Anal cirri lost, scars not seen. Morphological variation: All specimens shared the following morphological characters: short palps, chaetae, insertion and length of ventral cirri, slightly enlarged post-chaetal lobe. Although the paratypes are in poor condition, they do not seem to present the lamelliform dorsal tubercles. The tubercles might have been lost or this character could be age dependent, because the holotype has 22 segments whereas the paratypes have 18 segments. Remarks: The notochaetae and neurochaetae are closer to those present in Polaruschakov species. However, as described above, the lamelliform dorsal tubercles and the very reduced prostomium are unique characters, which allow differentiation of Polaruschakov lamellae sp. nov. from the other species belonging to Polaruschakov (Table 5). Etymology: The species name came from Latin ‘ lamellae ’ meaning lamella in plural. It refers to lamelliform dorsal tubercles. Genetic data: DNA sequencing for this species was successful for COI, 16S and 18S. The specimens shared 100% of genetic material in COI and 18S, and ≥ 99.5% in 16S. The average K2P distance for intraspecific variation was 0.0% for COI and 0.2% for 16S. Distribution: Based on the material examined (three specimens), this species has a wide distribution within the Clarion-Clipperton Fracture Zone, being sampled in BGR (type locality) and APEI#3 areas., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on pages 613-614, {"references":["Janssen A, Kaiser S, Meissner K, Brenke N, Menot L, Martinez Arbizu P. 2015. A reverse taxonomic approach to assess macrofaunal distribution patterns in abyssal Pacific polymetallic nodule fields. PLoS ONE 10: e 0117790."]}

BATHYEDITHIA PETTIBONE, 1976 Bathyedithia Pettibone, 1976: 53. – Levenstein, 1978: 167. – Uschakov, 1982: 133 (translated version). – Jirkov, 2001: 128. Type species: Macellicephaloides berkeleyi Levenstein, 1971a. Diagnosis (emended): Short body, dorsoventrally flattened, up to 26 segments. Frontal filaments absent. Eyes absent. Median and lateral antennae absent. Facial tubercle absent. Large palpophores. Tentacular segment fused with prostomium, tentaculophores without acicula or chaetae. Pharynx with seven to nine pairs of distal papillae; two pairs of jaws with serrated margin. Dorsal tubercles large (Bathyedithia tuberculata) or absent (Bathyedithia berkeleyi and Bathyedithia retierei sp. nov.). Elytrophores prominent, up to ten pairs, on segments 2, 4, 5, 7, 9, 11, 13, 15, 17 and 19. Parapodia subbiramous, notopodia shorter than neuropodia; noto- and neuropodia with elongate acicular lobe; tips of noto- and neuroaciculae not penetrating epidermis. Notochaetae distally with spinous rows; notochaetae more slender than neurochaetae. Neurochaetae numerous, serrated along both margins. From segment 3, ventral cirri inserted medially on neuropodia. Nephridial papillae present (Bathyedithia berkeleyi and Bathyedithia retierei sp. nov.) or absent (Bathyedithia tuberculata). Pygidium small, with dorsal (Bathyedithia tuberculata and Bathyedithia berkeleyi) or terminal anus (Bathyedithia retierei sp. nov.). Remarks: The diagnosis of genus Bathyedithia is emended to include a character observed in the species described below and the species Bathyedithia tuberculata Levenstein, 1981: ten pairs of elytrophores; as well as with characters observed in the new species: the presence of a terminal anus and the number of pairs of pharyngeal papillae., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on page 580, {"references":["Pettibone MH. 1976. Revision of the genus Macellicephala McIntosh and the subfamily Macellicephalinae Hartmann- Schroder (Polychaeta: Polynoidae). Washington: Smithsonian Institution Press.","Levenstein RYA. 1978. Polychaetes of the family Polynoidae (Polychaeta) from the deep-water trenches of the Western part of the Pacific. Transactions of the P. P. Shirov Institute of Oceanology Academy of Sciences of the USSR 112: 162 - 173.","Uschakov PV. 1982. Polychaetes of the suborder Aphroditiformia of the Arctic Ocean and the northwestern part of the Pacific Ocean. Families Aphroditidae and Polynoidae. Mnogoshchetinkovyye Chervil (Fauna of the USSR, Polychaeta) 2: 1 - 272.","Jirkov IA. 2001. Polychaeta of the Arctic Ocean. Moscow: Yanus-K Press.","Levenstein RYA. 1971 a. A new polychaete species of the genus Macellicephaloides from the Aleutian Trench. Journal of the Fisheries Research Board of Canada 28: 1429 - 1431.","Levenstein RYA. 1981. Some peculiarities of the distribution of the family Polynoidae from the Canada basin of the Arctic Ocean. Transactions of the P. P. Shirshov Institute of Oceanology 115: 26 - 36."]}

POLARUSCHAKOV PETTIBONE, 1976 Polaruschakov Pettibone, 1976: 55. – Uschakov, 1982: 124 (translated version). – Jirkov, 2001: 133. – Barnich & Fiege, 2003: 92. Type species: Macellicephala polaris Uschakov, 1957. Diagnosis (emended): Short body, dorsoventrally flattened, up to 25 segments. Frontal filaments absent. Eyesabsent.Medianandlateralantennaeabsent.Facial tubercle absent. Reduced palpophores. Tentacular segment fused with prostomium, tentaculophores without acicula or chaetae. Pharynx with seven pairs of distal papillae; two pairs of jaws with smooth margins or with a secondary small tooth (Polaruschakov lamellae sp. nov. and Polaruschakov omnesae sp. nov.). Dorsal tubercles present (Polaruschakov lamellae sp. nov. and Polaruschakov polaris) or absent (Polaruschakov reyssi, Polaruschakov limaae sp. nov. and Polaruschakov omnesae sp. nov.). Elytrophores prominent, up to ten pairs, on segments 2, 4, 5, 7, 9, 11, 13, 15, 17 and 19. Parapodia subbiramous, notopodia shorter than neuropodia; noto- and neuropodia with elongate acicular lobe; tips of noto- and neuroaciculae not penetrating epidermis. Notochaetae distally with spinous rows; notochaetae more slender than neurochaetae. Neurochaetae numerous, serrated along both margins. From segment 3, ventral cirri inserted medially on neuropodia. Nephridial papillae small. Pygidium small, with terminal anus. Remarks: The diagnosis of genus Polaruschakov is emended to include the following characters observed in the new species described below: jaws with small secondary tooth on margin and absence of flattened scale-like structures on segment 6. As highlighted for Hodor gen. nov., this feature, occasionally present on anterior segments, is likely to be a reproductive character, as suggested by its presence or absence without pattern among the taxa belonging to the Anantennata clade (i.e. without median and lateral antennae)., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on page 613, {"references":["Pettibone MH. 1976. Revision of the genus Macellicephala McIntosh and the subfamily Macellicephalinae Hartmann- Schroder (Polychaeta: Polynoidae). Washington: Smithsonian Institution Press.","Uschakov PV. 1982. Polychaetes of the suborder Aphroditiformia of the Arctic Ocean and the northwestern part of the Pacific Ocean. Families Aphroditidae and Polynoidae. Mnogoshchetinkovyye Chervil (Fauna of the USSR, Polychaeta) 2: 1 - 272.","Jirkov IA. 2001. Polychaeta of the Arctic Ocean. Moscow: Yanus-K Press.","Barnich R, Fiege D. 2003. The Aphroditoidea (Annelida: Polychaeta) of the Mediterranean Sea. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft 559: 1 - 167.","Uschakov PV. 1957. On the Fauna of polychaete worms (Polychaeta) from the Arctic and Antarctic. Zoologicheskii Zhurnal Akademiia Nauk SSSR 36: 1659 - 1672."]}

YODANOE DESBRUYERESI SP. NOV. (FIG. 21A–G; TABLES 1, 2) Type material: Holotype, MNHN-IA-TYPE 1843 (IFR448 b), complete, length 3.86 mm, width 0.64 mm, 17 segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, Ifremer license area, station 158, collected 15 April 2015, epibenthic sledge supra-net, start 14°3.411′N, 130°7.989′W, end 14°3.813′N, 130°6.481′W, 4946–4978 m depth, 3789 m trawling distance. Description (based on holotype): Holotype complete, 3.86 mm long and 0.64 mm wide for 17 segments (including tentacular segment), dorsoventrally flattened, tapering posteriorly; live specimen slightly translucent, bluish (Fig. 21A); ethanol-preserved specimen pale white, prostomium whitish. Prostomium bilobed, about as wide as long, lobes pronounced, anteriorly tapering to triangular peaks, located close to the notch; frontal filaments absent; median notch between prostomial lobes wide and moderately deep (Fig. 21B); eyes absent. Median antenna present, lateral antennae absent; ceratophore of median antenna, bulbous, large, short (shorter than anterior margin of prostomial lobes), inserted anteromedially on prostomium, in the notch, style missing. Palps smooth, tapering, long (reaching to segment 5; Fig. 21B). Facial tubercles absent; upper lip with few folds. Tentacular segment with elongate acicular lobe, inserted laterally and slightly ventral to prostomium; with acicula not penetrating epidermis, without chaetae (Fig. 21B); tentaculophores distinct, large, dorsal pair slightly longer than ventral one, inserted distally; styles missing. Pharynx not everted. Second segment with elytrophores, subbiramous parapodia, with chaetae and ventral cirri. Eight pairs of massive, cylindrical, elongate (longest on segments 9 and 11) elytrophores (Fig. 21D) present on segments 2, 4, 5, 7, 9, 11, 13 and 15 (all elytra missing). Cirrigerous segments with distinct, cylindrical dorsal cirrophores (Fig. 21C), inserted subdistally on notopodia; styles missing; dorsal tubercles present, forming cirriform branchial-like processes, small on segment 3, longest on segment 10 (as long as elytrophore of segment 9; Fig. 21D). Ventral cirri smooth, tapering, present from segment 2 to last segment; inserted basally on neuropodia of segment 2, style long (longer than tip of neuroacicular lobe); in subsequent segments inserted medially on neuropodia (Fig. 21C), style short (shorter than tip of neuroacicular lobe). Parapodia subbiramous; notopodia shorter than neuropodia (Fig. 21C). Notopodia arising from the dorsum, as two thickened ridges; notopodia subtriangular, tapering into long acicular lobe, tip of notoacicula not penetrating epidermis. Neuropodia large, rectangular to subtriangular, tapering into long acicular lobe, tip of neuroacicula not penetrating epidermis. Notochaetae few (six to 11 observed), short to long, slender, slightly curved, with developed spinous rows on convex side, with pointed tips (Fig. 21E); notochaetae as stout as neurochaetae. Neurochaetae moderate in number (23– 30 observed), short to long, distally flattened to concave, serrated along both margins, with pointed tips (Fig. 21F); lower group very short, leaf like (Fig. 21G). Nephridial papillae absent. Pygidium rounded, not enclosed by last segment; with dorsal anus (Fig. 21A). Anal cirri lost, scars not seen. Etymology: This species is dedicated to Dr Daniel Desbruyères (Laboratoire Environnement Profond, Ifremer, Brest, France) for his many contributions to the taxonomy and ecology of polychaetes mainly from extreme environments. Remarks: This species shares many similarities with Yodanoe sp. 659-3 but the palps are shorter in Yodanoe desbruyeresi gen. nov., sp. nov. (reaching segment 5) than in Yodanoe sp. 659-3 (reaching segment 7). Moreover, the K2P distance between these species was high (24.0% for COI and 19.3% for 16S). Genetic data: DNA sequencing for this species was successful for COI and 16S but not for 18S. Distribution: Only one specimen was sampled at a single station within the Clarion-Clipperton Fracture Zone in Ifremer license area (type locality)., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on pages 619-620

ABYSSARYA GEN. NOV. Type species: Abyssarya acus gen. nov., sp. nov., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on page 577

POLARUSCHAKOV OMNESAE SP. NOV. (FIG. 20A–G; TABLES 1, 2, 5) Type material: Holotype, MNHN-IA-TYPE 1841 (IFR424), complete, length 4.43 mm, width 0.83 mm, 19 segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, IOM license area, station 99, collected 4 April 2015, epibenthic sledge epi-net, start 11°2.296′N, 119°40.825′W, end 11°2.612′N, 119°39.512′W, 4398– 4402 m depth, 2529 m trawling distance. Paratype, MNHN-IA-TYPE 1842 (IFR530-1), complete, length 4.16 mm, width 0.81 mm, 20 segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, GSR license area, station 117, collected 7 April 2015, epibenthic sledge epi-net, start 13°52.317′N, 123°15.442′W, end 13°52.622′N, 123°14.263′W, 4498–4521 m depth, 3129 m trawling distance. Description (based on holotype and paratype): Holotype complete, 4.43 mm long and 0.83 mm wide for 19 segments (including tentacular segment), dorsoventrally flattened, posteriorly tapering; colour of live animal not known; ethanol-preserved specimen pale white, slightly translucent. Prostomium bilobed, wider than long, anterior lobes not developed, conical; frontal filaments absent; median notch between prostomial lobes moderately narrow and moderately deep (Fig. 20A); eyes absent. Median and lateral antennae absent. Palps smooth, tapering into thin tips, short (reaching segment 3); palpophores not enlarged (Fig. 20A). Facial tubercle absent. Upper lip with multiple minute folds. Tentacular segment fused to prostomium, with a pair of short lobes, inserted laterally and slightly below prostomium; without acicula or chaetae; tentaculophores distinct, bulbous, equal sized; styles smooth, tapering into thin tips, short (reaching segment 3), dorsal tentacular style slightly shorter than ventral tentacular style (Fig. 20A); ventrally to the tentaculophores is a distinct globular pad, located laterally to the mouth. Pharynx not everted in holotype; dissected in paratype (MNHN-IA-TYPE 1842), with seven pairs of distal papillae, subtriangular, equal sized; two pairs of jaws, each one with one main fang, outer margin with a very small, secondary tooth (small elevation; Fig. 20B). Second segment with elytrophores, subbiramous parapodia, chaetae and ventral cirri. Nine pairs of distinct, knob-like elytrophores present on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17 (all elytra missing). Cirrigerous segments with distinct, small dorsal cirrophores (Fig. 20C), inserted subdistally on notopodia; styles smooth, tapering into thin tips, long (slightly longer than tip of neuroacicular lobe); dorsal tubercles absent. Segment 6 without modification. Ventral cirri smooth, tapering into thin tips, present from segment 2 to last segment; inserted basally on neuropodia of segment 2, style short (shorter than tip of neuroacicular lobe); in subsequent segments inserted medially on neuropodia (Fig. 20C), style short (shorter than tip of neuroacicular lobe). Parapodia subbiramous; notopodia much shorter than neuropodia (Fig. 20C). Notopodia narrow, subtriangular, tapering into very short acicular lobe, tip of notoacicula not penetrating epidermis. Neuropodia large, subtriangular, tapering into long acicular lobe, tip of neuroacicula not penetrating epidermis. Notochaetae very few (one to three observed), short, slender, slightly curved, with distinct spinous rows on convex side, with blunt tips (Fig. 20D);notochaetae more slender than neurochaetae. Neurochaetae moderate in number (ten to 15 observed), long, distally flattened to concave, serrated along both margins, with pointed tips (Fig. 20E, F); slightly stouter in middle of fascicle. Nephridial papillae absent. Pygidium rounded, not enclosed by last segment; with terminal anus; with ventral papilla, rounded to ovoid (Fig. 20G). Anal cirri lost, scars not seen. Morphological variation: Specimens with 19 and 20 segments were found, which share most of the morphological characters given in the species description. However, the holotype shows a minute prostomial peak and a minute ventral papilla on the pygidium, whereas the paratype does not show those peaks but presents a more rounded, small, ventral papilla. Remarks: Polaruschakov omnesae sp. nov. is more similar to Polaruschakov polaris, with both having notochaetae with blunt tips, a wide notch and fewer chaetae than Polaruschakov reyssi. However, in Polaruschakov omnesae sp. nov. the neurochaetae tips are pointed and the palps are short (reaching segment 3), whereas in Polaruschakov polaris the neurochaetae tips are rounded and the palps are longer (Table 5). The average K2P distance among Polaruschakov lamellae sp. nov. and Polaruschakov omnesae sp. nov. was high (23.3% for COI and 24.4% for 16S). The presence of minute prostomial peaks could be an artefact of preservation, because its presence cannot be observed in the paratype. Etymology: This species is dedicated to Emmanuelle Omnes (Ifremer) for her help with laboratory work. Genetic data: DNA sequencing for this species was successful for COI, 16S and 18S. Both specimens shared 100% of genetic material in COI and 16S. 18S was not successfully sequenced for the paratype. The average K2P distance for intraspecific variation was 0.0% for both COI and 16S. Distribution: Based on the material examined (two specimens), this species has a restricted distribution within the Clarion-Clipperton Fracture Zone, being sampled in IOM (type locality) and GSR license areas., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on pages 617-619

NU AAKHU GEN. NOV., SP. NOV. (FIG. 17A–F; TABLES 1, 2) Type material: Holotype, MNHN-IA-TYPE 1836 (IFR341), complete, length 4.82 mm, width 0.76 mm, 18 segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, GSR license area, station 117, collected 7 April 2015, epibenthic sledge supra-net, start 13°52.317′N, 123°15.442′W, end 13°52.622′N, 123°14.263′W, 4498– 4521 m depth, 3129 m trawling distance. Description (based on holotype): Holotype complete, 4.82 mm long and 0.76 mm wide for 18 segments (including tentacular segment), dorsoventrally flattened; slightly tapering posteriorly; live specimen translucent, bluish; digestive system and chaetae internally visible, chaetae golden (Fig. 17A); ethanolpreserved specimen pale white, translucent. Prostomium bilobed, wider than long, lobes not pronounced, short, anteriorly rounded; fused with tentacular segment; frontal filaments absent; median notch between prostomial lobes shallow and moderately wide (Fig. 17A, C); eyes absent. Median and lateral antennae absent. Palps smooth, tapering, short (reaching segment 3), with small, distinct palpophores (Fig. 17C). Facial tubercles absent. Upper lip with minute folds. Tentacular segment fused to prostomium, with short lobe, inserted ventrolaterally to prostomium; without acicula or chaetae; tentaculophores very short, small, distinct, equal sized; tentacular styles short, smooth, tapering distally into filamentous tip; dorsal tentacular style (reaching segment 4) slightly longer than ventral tentacular style (Fig. 17C). Pharynx not everted. Second segment with elytrophores, subbiramous parapodia, with chaetae and ventral cirri. Nine pairs of very small, knob-like elytrophores present on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17 (all elytra missing). Cirrigerous segment with distinct, small dorsal cirrophores (Fig. 17D), inserted basally on notopodia; styles smooth, tapering, long to short (anteriorly, longer than tip of neuroacicular lobe; posteriorly, about as long as tip of neuroacicular lobe); dorsal tubercles absent. Segments 5 and 6 with large, swollen dorsal structure (Fig. 17A, B), interiorly whitish; smaller, bilobed on segment 5 (maybe because of elytrophore), larger on segment 6. Elytrophore not visible on segment 5 because of swelling. Ventral cirri smooth, tapering, present from segment 2 to last segment; inserted basally on neuropodia of segment 2, style long (longer than tip of neuroacicular lobe); in subsequent segments inserted subdistally on neuropodia (Fig. 17D), styles short (shorter than tip of neuroacicular lobe); on segments 3 and 4 shorter than those in posterior body; on segment 5 longer (approaching tip of neuroacicular lobe). Parapodia subbiramous (Fig. 17D). Notopodia very reduced to small, pointed acicular lobe, tip of notoacicula not penetrating epidermis. Neuropodia large, subtriangular, tapering into elongate acicular lobe, tip of neuroacicula not penetrating epidermis. Notochaetae absent. Neurochaetae moderate in number (16 observed), short to long, distally flattened to concave, with pronounced, widely spaced spines along both margins, with rounded tips (Fig. 17E, F); often, middle group with single, stouter neurochaeta. Nephridial papillae absent. Pygidium rounded, not enclosed by last segment; with terminal anus (Fig. 17A). Anal cirri lost, scars not seen. Remarks: As detailed in the genus section, Nu aakhu gen. nov., sp. nov. is unique in not having notochaetae and in having very short notoacicular lobes, very small elytrophores and neurochaetae with prominent spines along both margins. Etymology: Again, in the ancient Egyptian religion, ‘ áakhu ’ is one of the elements that compose the human soul. An ‘ áakhu ’ is the glorified spirit or a blessed soul which has passed the final judgement (the Weighing of the Heart). The term refers to the translucent character of the body of this worm. Genetic data: DNA sequencing was successful only for 18S but not for COI or 16S. Distribution: Only one specimen was sampled at a single station within the Clarion-Clipperton Fracture Zone in GSR license area (type locality)., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on pages 611-613

HODOR HODOR SP. NOV. (FIG. 12A–H; TABLES 1, 2) Type material: Holotype, MNHN-IA-TYPE 1825 (IFR655-2 - 1), complete, length 11.35 mm, width 1.68 mm, 24 segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, APEI#3, station 192, collected 21 April 2015, epibenthic sledge epi-net, start 18°44.807′N, 128°21.874′W, end 18°45.338′N, 128°20.418′W, 4821– 4820 m depth, 2799 m trawling distance. Description (based on holotype): Holotype complete, 11.35 mm long and 1.68 mm wide for 24 segments (including tentacular segment), dorsoventrally flattened, posteriorly tapering; colour of live animal not known; ethanol-preserved specimen pale white (Fig. 12A). Prostomium bilobed, about as long as wide, lobes subtriangular, poorly developed, anteriorly tapering into blunt peaks, extending until superior lip; frontal filaments absent; median notch between prostomial lobes narrow and shallow (Fig. 12C); eyes absent; a pair of internal white ganglia visible through translucent epidermis, dorsolaterally located on prostomium. Median and lateral antennae absent. Palps smooth, tapering, very long (reaching segment 9), inserted on large, rounded palpophores (Fig. 12C). Facial tubercle absent. Tentacular segment fused to prostomium, well developed, with a pair of short lobes, inserted laterally and slightly below prostomium; without acicula or chaetae; tentaculophores large, bulbous, equal sized; dorsal tentacular style smooth, tapering, short (reaching segment 4); ventral tentacular style missing (Fig. 12C). Pharynx not everted. Second segment with elytrophores, subbiramous parapodia, chaetae and ventral cirri. Nine pairs of large, globular elytrophores (Fig. 12B, D) present on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17 (all elytra missing); with dorsal cirrophores on last segments. Cirrigerous segments with large, bulbous dorsal cirrophores (Fig. 12B), inserted subdistally on notopodia; styles missing. Segments 6 and 8 with large, swollen dorsal structure (Fig. 12A, B), located basally to cirrophores, interiorly whitish; smaller on segment 6, bigger on segment 8. Dorsal tubercles absent. Ventral cirri smooth, tapering, present from segment 2 to last segment; inserted basally on neuropodia of segment 2, style long (longer than tip of neuroacicular lobe); in subsequent segments inserted medially on neuropodia (Fig. 12D), style short (shorter than tip of neuroacicular lobe). Parapodia subbiramous; notopodia reduced, much short than neuropodia (Fig. 12D). Notopodia arising from the dorsum as two thickened ridges; narrow, subtriangular, tapering into long acicular lobe, tip of notoacicula not penetrating epidermis. Neuropodia large, rectangular to subtriangular, tapering into long acicular lobe, tip of neuroacicula not penetrating epidermis. Notochaetae variable in number (one to 16 observed), long, slender, slightly curved with distinct, faint spinous rows on convex side, with blunt tips preceded by subdistally smooth margin (Fig. 12E); notochaetae more slender than neurochaetae. Neurochaetae of two types: (1) moderate in number (12–28 observed), long to very long, distally flattened to concave, serrated along both margins, with pointed tips (Fig. 12F); and (2) middle and lower group on segments 3–7 modified, moderate in number (16 observed), stouter, short to long, distally flattened to concave, with coarse spines along both margins, spines concentrated basally and well spaced later, middle part with smooth margins (most of or less of their length), subdistally smooth or with one or two spines, blunt tip, tip margin slightly lighter (Fig. 12G, H). Nephridial papillae present on segments 11, 12 and 13, small, bulbous. Last segment very reduced. Pygidium rounded, not enclosed by last segment; with terminal anus (Fig. 12A). Anal cirri lost, scars not seen. Remarks: Hodor hodor gen. nov., sp. nov. presents many similarities with Hodor anduril gen. nov., sp. nov., including the number of segments, prostomium and parapodial shape, chaetae and number of nephridial papillae pairs. However, the palps in Hodor hodor gen. nov., sp. nov. are longer (reaching segment 9) than the palps in Hodor anduril gen. nov., sp. nov. (reaching segment 2). Furthermore, the average K2P distance between these species was 14.2% for COI and 6.1% for 16S. Interestingly, the morphological variation observed in Hodor anduril gen. nov., sp. nov. specimens could also indicate some dissimilarity within Hodor hodor gen. nov., sp. nov. specimens, which will necessitate care in the identification of any further specimens. In addition, both species have overlapping distribution in APEI#3. Etymology: This species is dedicated to Hodor, one of P.B.’s favourite characters in the novel ‘ A song of ice and fire ’ by George R. R. Martin. Genetic data: DNA sequencing for this species was successful for COI, 16S and 18S. Distribution: Only one specimen was sampled at a single station within the Clarion-Clipperton Fracture Zone in APEI#3 area (type locality)., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on pages 598-600

BATHYEDITHIA RETIEREI SP. NOV. (FIG. 6A–G; TABLES 1, 2) Type material: Holotype, MNHN-IA-TYPE 1814 (IFR451 b), complete, length 3.81 mm, width 0.71 mm, 20 segments (including tentacular segment), Equatorial Eastern Pacific Ocean, Clarion-Clipperton Fracture Zone, Ifremer license area, station 158, collected 15 April 2015, epibenthic sledge supranet, start 14°3.411′N, 130°7.989′W, end 14°3.813′N, 130°6.481′W, 4946–4978 m depth, 3789 m trawling distance. Description (based on holotype): Holotype complete, 3.81 mm long and 0.71 mm wide for 20 segments (including tentacular segment), dorsoventrally flattened, posteriorly tapering; live specimen bluish, transparent (Fig. 6A); ethanol-preserved specimen pale white. Prostomium bilobed, wider than long, anteriorly rounded, lobes not developed; frontal filaments absent; median notch between prostomial lobes narrow and shallow (Fig. 6A, B); eyes absent. Median and lateral antennae absent. Palps smooth, tapering into thin tips, short (reaching to segment 2–3), inserted on rounded palpophores (Fig. 6B). Facial tubercle absent. Tentacular segment fused to prostomium, with a pair of short lobes, inserted laterally and slightly ventral to prostomium; without acicula or chaetae; tentaculophores distinct, bulbous, equal sized; styles smooth, tapering into thin tips, short (reaching to segment 4), dorsal and ventral tentacular cirri of similar length (Fig. 6B). Pharynx dissected, with seven pairs of subtriangular distal papillae of similar size; two pairs of jaws with main fang, serrated margin (one pair of jaws with nine to 11 teeth and the other pair with 13 teeth; Fig. 6C). Second segment with elytrophores, subbiramous parapodia, chaetae and ventral cirri. Ten pairs of distinct, knob-like elytrophores present on segments 2, 4, 5, 7, 9, 11, 13, 15, 17 and 19 (elytron still attached on segment 7); elytra very small (approaching the margins of preceding and subsequent segments, covering notopodia), smooth margin; surface with sparse, rounded microtubercles. Cirrigerous segments with distinct, small dorsal cirrophores (Fig. 6D), inserted subdistally on notopodia; styles of dorsal cirri smooth, tapering into thin tips, short (as long as tip of neuroacicular lobe); dorsal tubercles absent. Segment 6–8 without any structures. Ventral cirri smooth, tapering into thin tips, present from segment 2 to last segment; inserted basally on neuropodia of segment 2, style long (longer than tip of neuroacicular lobe); in subsequent segments inserted medially on neuropodia, style short (shorter than tip of neuroacicular lobe). Parapodia subbiramous; notopodia reduced, much shorter than neuropodia (Fig. 6D). Notopodia narrow, subtriangular, tapering into short acicular lobe, tip of notoacicula not penetrating epidermis. Neuropodia large, lanceolate, tapering into long acicular lobe, tip of neuroacicula not penetrating epidermis. Notochaetae very few (one or two observed), short, slender, slightly curved with distinct, faint spinous rows on convex side, with blunt tips preceded by smooth margin (Fig. 6E); notochaetae more slender than neurochaeta. Neurochaetae of two types: (1) variable in number (three to 20 observed), long, distally flattened to concave, serrated along both margins, with abrupt pointed tips (Fig. 6F); and (2) middle group mostly in anterior segments, few (five observed), slightly stouter, long, distally flattened to concave, coarsely serrated along both margins, with blunt tips (Fig. 6G). The neurochaetae present a central rib that is more or less evident. Nephridial papillae present on segments 10 and 11, small, digitiform. Pygidium rounded, not enclosed by last segment; with terminal anus (Fig. 6A). Anal cirri lost, scars not seen. Remarks: The new species is very close to Polaruschakov species having seven pairs of pharyngeal papillae, but even closer to Bathyedithia in having serrated jaws and rounded palpophores. Bathyedithia retierei sp. nov. differs from the two other species of Bathyedithia in having seven pairs of pharyngeal papillae and lanceolate neuropodia. Furthermore, in Bathyedithia retierei sp. nov. the nephridial papillae are present on segments 10 and 11, whereas in Bathyedithia tuberculata they are present from segment 7 to the end of the body, and they are absent in Bathyedithia berkeleyi. Etymology: This species is dedicated to Professor Christian Retière (Muséum National d’Histoire Naturelle, Dinard, France) for his many contributions to French benthic research. Genetic data: DNA sequencing for this species was successful for 16S and 18S (only 720 bp) but not for COI. Distribution: Only one specimen was sampled at a single station within the Clarion-Clipperton Fracture Zone in Ifremer license area (type locality)., Published as part of Bonifácio, Paulo & Menot, Lénaïck, 2019, New genera and species from the Equatorial Pacific provide phylogenetic insights into deep-sea Polynoidae (Annelida), pp. 555-635 in Zoological Journal of the Linnean Society 185 on pages 580-581

Polynoidae Kinberg, 1856 has five branchiate genera: Branchipolynoe Pettibone, 1984, Branchinotogluma Pettibone, 1985, Branchiplicatus Pettibone, 1985, Peinaleopolynoe Desbruyères & Laubier, 1988, and Thermopolynoe Miura, 1994, all native to deep-sea, chemosynthetic-based habitats. Of these, Peinaleopolynoe has two accepted species; Peinaleopolynoe sillardi Desbruyères & Laubier, 1988 (Atlantic Ocean) and Peinaleopolynoe santacatalina Pettibone, 1993 (East Pacific Ocean). The goal of this study was to assess the phylogenetic position of Peinaleopolynoe, utilizing DNA sequences from a broad sampling of deep-sea polynoids. Representatives from all five branchiate genera were included, several species of which were sampled from near the type localities; Branchinotogluma sandersi Pettibone, 1985 from the Galápagos Rift (E/V “Nautilus”); Peinaleopolynoe sillardi from organic remains in the Atlantic Ocean; Peinaleopolynoe santacatalina from a whalefall off southern California (R/V “Western Flyer”) and Thermopolynoe branchiata Miura, 1994 from Lau Back-Arc Basin in the western Pacific (R/V “Melville”). Phylogenetic analyses were conducted using mitochondrial (COI, 16S rRNA, and CytB) and nuclear (18S rRNA, 28S rRNA, and H3) genes. The analyses revealed four new Peinaleopolynoe species from the Pacific Ocean that are formally described here: Peinaleopolynoe orphanae Hatch & Rouse, sp. nov., type locality Pescadero Basin in the Gulf of California, Mexico (R/V “Western Flyer”); Peinaleopolynoe elvisi Hatch & Rouse, sp. nov. and Peinaleopolynoe goffrediae Hatch & Rouse, sp. nov., both with a type locality in Monterey Canyon off California (R/V “Western Flyer”) and Peinaleopolynoe mineoi Hatch & Rouse, sp. nov. from Costa Rica methane seeps (R/V “Falkor”). In addition to DNA sequence data, the monophyly of Peinaleopolynoe is supported by the presence of ventral papillae on segments 12–15. The results also demonstrated the paraphyly of Branchinotogluma and Lepidonotopodium Pettibone, 1983 and taxonomic revision of these genera is required. We apply the subfamily name Lepidonotopodinae Pettibone 1983, for the clade comprised of Branchipolynoe, Branchinotogluma, Bathykurila, Branchiplicatus, Lepidonotopodium, Levensteiniella Pettibone, 1985, Thermopolynoe, and Peinaleopolynoe.

Polynoid scale-worms have been found living as commensals with deep-water antipatharians (commonly known as black corals) in the Potiguar Basin, off Rio Grande do Norte State, Northeastern Brazil. In this paper two polychaete species and four black corals species are redescribed. Benhamipolynoecf.antipathicola and Parahololepidellacf.greeffi, and the black coral Stylopathesadinocrada Opresko, 2006 are recorded for the Southwestern Atlantic. Benhamipolynoecf.antipathicola was first described from off New Zealand and the Malay Archipelago, as symbiont with the black coral Stylopathestenuispina (Silberfeld, 1909). It was later reported for the North Atlantic, off Florida, associated with Stylopathescolumnaris (Duchassaing, 1870). In our study, B.cf.antipathicola was found in association with the black coral S.adinocrada. Parahololepidellacf.greeffi was first described as a free-living from shallow waters off São Tomé and Cabo Verde Islands, West Africa, and later reported as symbiont with the black coral Tanacetipathescf.spinescens in the same location. Our data expand both the geographical distribution and the host range of this species which is reported for the first time as symbiont with Tanacetipathesbarbadensis (Brook, 1889), T.tanacetum (Pourtalès, 1880) and T.thamnea (Warner, 1981) in Brazil. The aim of this study is to discuss commensal associations between two species of scale-worm polynoids and black corals found in the Southwestern Atlantic, and also reporting their global distribution. Finally, we provided an updated list of the commensal polynoids and their black coral hosts.

Este artículo contiene 65 páginas, 26 figuras, 1 tabla., Phyllodocida is a clade of errantiate annelids characterized by having ventral sensory palps, anterior enlarged cirri, axial muscular proboscis, compound chaetae (if present) with a single ligament, and of lacking dorsolateral folds. Members of most families date back to the Carboniferous, although the earliest fossil was dated from the Devonian. Phyllodocida holds 27 well-established and morphologically homogenous clades ranked as families, gathering more than 4600 currently accepted nominal species. Among them, Syllidae and Polynoidae are the most specious polychaete groups. Species of Phyllodocida are mainly found in the marine benthos, although a few inhabit freshwater, terrestrial and planktonic environments, and occur from intertidal to deep waters in all oceans. In this review, we (1) explore the current knowledge on species diversity trends (based on traditional species concept and molecular data), phylogeny, ecology, and geographic distribution for the whole group, (2) try to identify the main knowledge gaps, and (3) focus on selected families: Alciopidae, Goniadidae, Glyceridae, Iospilidae, Lopadorrhynchidae, Polynoidae, Pontodoridae, Nephtyidae, Sphaerodoridae, Syllidae, Tomopteridae, Typhloscolecidae, and Yndolaciidae. The highest species richness is concentrated in European, North American, and Australian continental shelves (reflecting a strong sampling bias). While most data come from shallow coastal and surface environments most world oceans are clearly under-studied. The overall trends indicate that new descriptions are constantly added through time and that less than 10% of the known species have molecular barcode information available, We acknowledge support of the publication fees by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI) and the Open Access Publication Funds of the Georg-August-Universität Göttingen. This research was funded by the Spanish “Agencia Estatal de Investigación” (AEI) and the European Funds for Regional Development (FEDER), Research Project PopCOmics (CTM2017-88080) to DM; the Russian Scientific Foundation for Basic Research, grant no. RFBR 18-05-00459 to TAB; Fundação para a Ciência e a Tecnologia (FCT), contract foreseen in the Decree-Law 57/2016 (Nrs 4-6, art. 23), changed by Law 57/2017 to AR and FCT/MCTES to CESAM (UIDP/50017/2020+UIDB/50017/2020) through national funds; São Paulo Research Foundation (FAPESP), fellowship proc. 2007/53040-9 to MVF; Spanish MINECO, AEI, Comunidad Autónoma de las Islas Baleares, European Social Funds and Ramón y Cajal program, RYC-2016-20799 to MC; FCT and ESF (SFRH/BD/131527/2017) through a PhD grant to MALT.

Among polychaetes, polynoids have the highest number of symbiotic species found living with a wide variety of marine invertebrates, including other polychaetes. Lepidasthenia Malmgren, 1867 and Lepidametria Webster, 1879 were regarded as synonyms but belong to different subfamilies, although both have species associated with thelepodid or terebellid polychaetes. In this contribution Lepidasthenia loboi sp. n. is described from several specimens associated with the thelepodid Thelepus antarcticus Kinberg, 1867, collected on a rocky shore near Puerto Madryn, Argentina. Lepidasthenia loboi sp. n. can be confused with Lepidasthenia esbelta Amaral & Nonato, 1982 because both live with Thelepus, are of similar sizes with similar pigmentation patterns, and have giant neurochaetae. However, in Lepidasthenia loboi sp. n. all eyes are of the same size, cephalic and parapodial cirri are tapered and mucronate, the second pair of elytra is larger than the third, the ventral cirri arise at the base of parapodia such that they do not reach chaetal lobe tips, and neuraciculae are tapered. On the contrary, in Lepidasthenia esbelta the posterior eyes are larger than anterior ones, cephalic and parapodial appendages are swollen subdistally, the second and third pairs of elytra are of the same size, the ventral cirri arise medially such that their tips reach the neurochaetal lobe tips, and the neuraciculae have falcate tips. Some comments about other genera in the Lepidastheniinae, a simplified key to its genera, and a key to Lepidasthenia species with giant neurochaetae are also included.

Branchinotogluma bipapillata n. sp. urn:lsid:zoobank.org:pub:757A9897-4ADC-4C79-9FBB-60CF30722852 (Figs. 1���7) Material examined. Holotype (RSIO35275), female, Southwest Indian Ocean Ridge, Longqi vent field, 49.6502��E, 37.7839��S, depth 2761 m, Stat. 35II-Dive94, coll. HOV Jiaolong, R / V Xiangyanghong 9, 11 January 2015: 26.6 mm long, 5.0 mm wide (without parapodia), 21 segments. Three paratypes (RSIO35274, female; RSIO35277, male; RSIO35402, female), same data as RSIO35275: 23.3 ��� 32.3 mm long, 4.0 ��� 6.5 mm wide (without parapodia); 1 paratype (RSIO3530, anterior partial), female, Southwest Indian Ocean Ridge, Duanqiao vent field, 50.47��E, 37.66��S, depth 1732 m, Stat. 34IV-SWIR-S035-TVG08, coll. television grab, R/V Dayang 1, 13 April 2015. Description. Body short, 21 segments, slightly tapered anteriorly and posteriorly, with flattened ventrum and arched dorsum (Figs. 1A���D). 10 pairs of elytra, subreniform or oval, large, thick, smooth (Figs 1I, J), overlapping, covering dorsum and present on segments 2, 4, 5, 7, 9, 11, 13, 15, 17 and 19 (Fig. 1A, C); elytrophores short (Figs 2G, 3A, C���F). Dorsal tubercles present on non-elytra-bearing segments (Figs 2G, 3B, G). Branchiae arborescent, with short terminal filaments, present in two groups attached to bases of notopodia and dorsal tubercles or elytrophore respectively (Figs 2G, 3B���C, E���G); beginning on segment 3, becoming larger in the middle region of body, and continuing to segment 19, where they are found as single small group. Prostomium deeply bilobed, triangular anterior lobes with minute frontal filaments; median antenna with cylindrical ceratophore (extending to tips of anterior lobes of prostomium) in anterior notch, style long, significantly surpassing prostomium; without eyes; palps stout, tapering, with slender tips (Figs 1E���H). First tentacular segment fused to prostomium, not distinct dorsally, forming lateral lips (Fig. 1H); cylindrical tentaculophores lateral to prostomium, achaetous, each with small acicular lobes on medial side and acicula visible through the epidermis (Figs. 1E���F), 2 pairs of tentacular cirri slender and as long as palps (Fig. 1F). Segment 2 with biramous parapodia bearing prominent notopodial bract and the first pair of elytrophores (Figs 3A, D); ventral cirri attached basally to neuropodia, shorter than tentacular cirri but much longer than that on following segments (Figs 1B, D, H, 3A, D). Mouth located between segments 1 and 2 ventrally. Thick muscular pharynx (everted) with 5 pairs of dorsal and ventral papillae surrounding the opening (Fig. 2A), three medial pairs with small distal cirri (Fig. 2A lower left); 6 pairs of lateral tapered papillae located at the base of the pharynx (Fig. 2C, D); two pairs of prominent jaws, curved, amber colored, minutely denticulate on inner borders (Fig. 2A, B). Parapodia biramous, neuropodia usually larger than notopodia, with a few exceptions on some posterior segments (e.g., parapodia on segments 20 and 21 of holotype (Fig. 5B���C)). Notopodia with elongate acicular lobes on lower sides (Figs. 3A���G), lacking in bracts except on segment 2 (Fig. 3A, D). Neuropodia long, with triangular prechaetal lobes and slightly shorter and rounded postchaetal lobes; lobes deeply notched on upper part, with projecting small lobe on dorsal base (Figs. 3A���G). Dorsal cirri attached to the posterodorsal sides of notopodia on non-elytrigerous segments, with rather long cylindrical cirrophores and long filiform styles, extending beyond neurochaetae (Figs 2G, 3B, G). Ventral cirri on segment 2 long, extending to end of neuropodia (Figs 1H, 3A, D); short on segments 3���21, extending to middle part of neuropodia (Figs 2E���F, H, 3B, C, E���G). Notochaetae few (usually less than 20), straight or slightly coiled subdistally, short to long, forming radiating bundles, smooth, much stouter than neurochaetae, acicular, tapering to pointed tips (Fig. 4A, B, I). Neurochaetae very numerous, forming fan-shaped bundles, slender (Fig. 3B���G). Supraacicular neurochaetae (Fig. 4C, D, J) straight, with pointed tips (sometimes very slightly hooked); two rows of widely-spaced spines beginning subdistally and extending to near tips, finely spinous distally. Upper subacicular neurochaetae (Fig. 4E, F, K���L) long, decreasing in length ventrally, slightly wider and more numerous than supraacicular neurochaetae; two rows of prominent spines emerging subdistally and extending to near end, spinous region shorter than that on supraacicular neurochaetae; tips bare and hooked. Lower subacicular neurochaetae (Fig. 4G, H, M, N) short, delicate, tips flattened, with two rows of feather-like serration. Tips of notochaetae and neurochaetae usually embedded in sulfide (Figs 3A���G, 5A���F). Ventral papillae 5 pairs, short, with blunt tips, present on segments 11���15 (Fig. 2E). Pygidium with pair of long and slender anal cirri (one anal cirrus broken off on collected females, Figs 1B, 2H). On male (only one specimen collected, paratype RSIO35277), elytra much smaller on segment 19; branchiae present on segments 3���18. Ventral papillae 2 pairs, long, tapering, with slender tips, present on segments 12���13 (Fig. 2F); four pairs of rounded ventral lamellae present on segments 14���17 (Fig. 2F). Segments 18���19 slightly modified. Parapodia of segment 18 biramous, with notopodia as strong as neuropodia; branchiae present at base of notopodia as single small branch. Segment 19 (Fig. 5D) with much smaller elytrophores and smaller elytra, without branchiae; neuropodia reduced, shorter than notopodia; ventral cirri attached at base of ventral sides of neuropodia, extending to tips of postchaetal lobes; neurochaetae similar to that on previous segments (Fig. 5G���H), except the presence of some slender capillary neurochaetae, bearing widely-spaced lateral spines (marked with an arrow in Fig. 5G). Segments 20 and 21 fused slightly, modified more strongly than previous two; parapodia, strongly reduced; notopodial acicular lobes fused to cirrophores of dorsal cirri, with few notochaetae; ventral cirri attached near base of parapodia, long, extending beyond the end of neurochaetae (Figs 2I, 5E, F); neurochaetae consisting exclusively of capillary chaetae, with scattered spines (Fig. 5I). Pygidium with pair of anal cirri, long, stout, tapered, basally inflated but not fused (Fig. 2I). Characters B. segonzaci B. trifurcus B. burkensis B. marianus B. tunnicliffeae B. hessleri B. sandersi B. japonica B. elytropapillata B. bipapillata Notopodial bract present not mentioned present on without present on present on present on present on starting on present on segment 2 segment 2 elytrigerous segment 19 in segment 19 segment 2 segment 2 segments males, and on segments 2 in both males and females On males 1 pair of long 1 pair of papillae not mentioned 1 pair of long 4 pairs of 1 pair of papillae 4 pairs of 1 pair of long 1 pair of long 2 pairs of long papillae on on segment 12; 5 papillae on papillae on on segment 12 papillae on papillae on papillae on papillae on segment 12; 5 pairs of lamellae segment 12; 6 segments 12-15; and 5 pairs of segments 12-15 segment 12; 5 segment 12 and 5 segments 12-13; pairs of ventral on segments pairs of lamellae 2 pairs of lamellae on and 3 pairs of pairs of pairs of lamellae 4 pairs of lamellae on 13-17 on segments rounded lamellae segments 13-17 lamellae on lamellae on on segments 13-17 lamellae on segments 13-17 13-18. on segments segments 16-18 segments 13-17 segments 14-17 Ventral 16-17 papillae On females without lacking in 7 pairs on not mentioned not mentioned 6 pairs of with or without 5 without 5 pairs of short 5 pairs of short lamellae and segments 11-17 lamellae on pairs of small papillae on papillae on bearing short segments 11-16 squarish papillae segments 11-15 segments 11-15 papillae on on segments segment 11 11-15 Notopodia small modified not mentioned short Small small; with short not modified small; with highly compressed slightly slightly, bearing notochaetae; and smooth short and modified; modified; very long dorsal small notopodial notochaetae; notochaetae with short and notopodia and cirri acicular lobe bearing delicate stout notochaetae; neuropodia fused to rounded small notopodial subequal in size cirrophore of flattened lamella acicular lobe fused dorsal cirrus; to cirrophore of ciliated on lower dorsal cirrus Modified side segment 18 Neuropodia slender not mentioned not mentioned coincal, short; Small achaetous, small not mentioned small, long neuropodia fused ciliated on upper capillary to form a lamina side; with long neurochaetae on ventral side; capillary with long capillary neurochaetae neurochaetae Remarks. In previous studies, Branchinotogluma bipapillata n. sp. was assigned to Peinaleopolynoe (Copley et al., 2016; Zhou et al., 2018), which is characterized by 9���10 pairs of elytra, branchiae beginning on segment 2, one small acicular lobe on each tentaculophores, the absence of bracts on all parapodia, 7 pairs of border papillae surrounding pharynx and 4 pairs of ventral papillae on segments 12���15 (Pettibone 1993). Branchinotogluma bipapillata n. sp. and Peinaleopolynoe species do share one character, tentaculophores with small acicular lobes (Figs 1E���F), and this character has not been reported in other branchiate scale worms, such as Branchinotogluma (Zhang et al., 2018a) and Branchipolynoe (Zhou et al., 2017). However, characters, such as the number and distribution of branchiae, notopodial bracts on segment 2 (Fig. 3A, D), modified posterior segments on male (Fig. 4D���F), make the new species more like Branchinotogluma species. The COI -based ML tree also shows that it is most strongly affiliated with several other Branchinotogluma species, rather than to the published sequences of an as yet undescribed species of Peinaleopolynoe (Fig. 6). However, COI is insufficient to resolve the phylogenetic relationships among all those branchiate scale worms comprehensively (only a few species can be used) as some nodes on the ML tree are poorly supported. Using the limited dataset available for branchiate worms, a combined analysis (Fig. 7) based on concatenated genes (COI, 16S and 18S) reveals a similar pattern of this group to previous studies (Zhang et al. 2018a; Zhang et al. 2018b): (1) Branchiate scale worms (Branchinotogluma and Branchipolynoe species) form a well-supported clade; (2) Branchinotogluma is paraphyletic, while the three Branchipolynoe species tend to be more deeply placed in the branch, forming one monophyletic subclade. The placement of B. bipapillata n. sp. in the clade is also well supported, and it is sister to the Branchinotogluma japonicus + Branchipolynoe branch. Thus, either morphological or molecular evidences suggest that the placement of the new species in Branchinotogluma is more reasonable than in Peinaleopolynoe, although more genetic markers from a wider range of species are needed for further revision of this clade. Nine recognized species have currently been placed in Branchinotogluma (Desbruy��res et al. 2006; Zhang et al., 2018a). It is easy to distinguish the new species from its congeners by comparison of their characters (Table 1). Characters, such as the presence of small acicular lobes on tentacular segment (Fig. 1E���F), two pairs of long conical ventral papillae on males (Fig. 2F), five pairs of dorsal and ventral papillae surrounding the opening of pharynx (Fig. 2A) and the presence of long ventral cirri on segments 20 and 21 of male (Figs 2I, 5E���F), can each separate B. bipapillata n. sp. from all other members in this genus. Pharynx papillae and ventral papillae show high degree of diversity, as there are six and five different types in the genus regarding their size, shape and distribution pattern (Table 1), making them useful identification tools at the species level. The smooth and stout notochaetae are also unusual in the genus (Fig. 4A, B, I), as it is present in only one species (B. sandersi) besides B. bipapillata n. sp. Another unique feature of the new species is the lower subacicular neurochaetae with delicate feather-like spines (Fig. 4G���H, M���N). Although it has not been reported from other Branchinotogluma species (Miura & Hashimoto 1991; Miura & Desbruy��res 1995; Pettibone 1985; Pettibone 1988; Pettibone 1989; Zhang et al. 2018a), we are not sure if it is unique to the new species as details of neurochaetae are sometimes insufficient in original description. For example, an SEM image of B. hessleri neurochaetae (Fig. 8 in page 220 of Desbruy��res et al. 2006) shows spines with similar outline to the lower subacicular neurochaetae to B. bipapillata n. sp., however the details of the spines are missing in either the original description (Pettibone 1985) or the later publication (Desbruy��res et al. 2006). This makes the direct comparison of neurochaetae between different species difficult. Other characters used to do pairwise comparison in the genus are also listed in Table 1. Coloration. Color of living animal light red, color in alcohol pale white. Etymology. " bipapillata " ("bi" + "papillata"), meaning two papillae, refers to the two pairs of long segmental ventral papillae in males. Distribution. Currently only known from Longqi and Duanqiao hydrothermal vent fields, Southwest Indian Ocean Ridge., Published as part of Zhou, Yadong, Wang, Yueyun, Zhang, Dongsheng & Wang, Chunsheng, 2018, Branchinotogluma bipapillata n. sp., a new branchiate scale worm (Annelida: Polynoidae) from two hydrothermal fields on the Southwest Indian Ridge, pp. 527-540 in Zootaxa 4482 (3) on pages 528-539, DOI: 10.11646/zootaxa.4482.3.5, http://zenodo.org/record/1440787, {"references":["Zhou, Y., Zhang, D., Zhang, R., Liu, Z., Tao, C., Lu, B., Sun, D., Xu, P., Lin, R., Wang, J. & Wang, C. (2018) Characterization of vent fauna at three hydrothermal vent fields on the Southwest Indian Ridge: implications for biogeography and interannual dynamics on ultraslow-spreading ridges. Deep-Sea Research Part I, 137, 1 - 12. https: // doi. org / 10.1016 / j. dsr. 2018.05.001","Zhang, Y., Chen, C. & Qiu, J. (2018 a) Sexually dimorphic scale worms (Annelida: Polynoidae) from hydrothermal vents in the Okinawa Trough: Two new species and two new sex morphs. Frontiers in Marine Science, 5, 112. https: // doi. org / 10.3389 / fmars. 2018.00112","Zhou, Y., Zhang, D., Lu, B. & Wang, C. (2017) Description of a new branchiate scale-worm (Polychaeta: Polynoidae) from the hydrothermal vent on Southwest Indian Ocean Ridge. Zootaxa, 4282 (1), 123 - 134. https: // doi. org / 10.11646 / zootaxa. 4282.1.7","Zhang, Y., Sun, J., Rouse, G. W., Wiklund, H., Pleijel, F., Watanabe, H. K., Chen, C., Qian, P. & Qiu, J. (2018 b) Phylogeny, evolution and mitochondrial gene order rearrangement in scale worms (Aphroditiformia, Annelida). Molecular Phylogenetics and Evolution, 125, 220 - 231. https: // doi. org / 10.1016 / j. ympev. 2018.04.002","Desbruyeres, D., Segonzac, M. & Bright, M. (2006) Handbook of Deep-Sea Hydrothermal Uent. Zugleich Kataloge der Oberosterreichischen Landesmuseen, Brest, 544 pp.","Miura, T. & Hashimoto, J. (1991) Two new branchiate scale-worms (Polynoidae: Polychaeta) from the hydrothermal vent of the Okinawa Trough and the volcanic seamount off Chichijima Island. Proceedings of the Biological Society of Washington, 104, 166 - 174.","Miura, T. & Desbruyeres, D. (1995) Two new species of Opisthotrachopodus (Polychaeta: Polynoidae: Branchinotogluminae) from the Lau and the North Fiji Back-arc Basins, southwestern Pacific Ocean. Proceedings of the Biological Society of Washington, 108, 583 - 595.","Pettibone, M. H. (1985) Additional branchiate scale-worms (Polychaeta: Polynoidae) from Galapagos hydrothermal vent and rift-area off Western Mexico at 21 ° N. Proceedings of the Biological Society of Washington, 98, 447 - 469.","Pettibone, M. H. (1988) New species and new records of scaled polychaetes (Polychaeta: Polynoidae) from hydrothermal vents of the Northeast Pacific Explorer and Juan de Fuca Ridges. Proceedings of the Biological Society of Washington, 101, 192 - 208.","Pettibone, M. H. (1989) New species of scale-worms (Polychaeta: Polynoidae) from the hydrothermal rift-area of the Mariana Back-arc Basin in the Western Central Pacific. Proceedings of the Biological Society of Washington, 102, 137 - 153."]}

A new species of Branchinotogluma, found at two hydrothermal vent fields on Southwest Indian Ocean Ridge, is described herein. It can be distinguished from its congeners by the small acicular lobe on the tentacular segment, the stout smooth notochaetae, 5 pairs of dorsal and ventral papillae surrounding the pharynx, 2 pairs of long ventral papillae and 4 pairs of ventral lamellae on males, and modified parapodia on posterior segments. Sexual dimorphism is also reported in the new species, as male and female individuals display differences in characters on the ventral papillae and posterior segments.

Macellicephala patersoni sp. nov. (Figures 2F and Figures 9, 10; Table 2.) Macellicephala sp. B in Neal et al. (2017) [record]. Material examined. Holotype, NHMUK.2018.1009, Pine Island Bay, Amundsen Sea, Southern Ocean, cruise JR 179, station BIO4 -EBS-3D, collected on 07/03/2008, epibenthic sledge, epi-net, 74°23'25.836''S, 104°46'4.512''W, 506 m depth. Description (based on holotype). Medium sized species; holotype complete specimen in good condition, 13.5 mm long, 2 mm wide excluding parapodia and 6.55 mm wide including parapodia, 18 segments (segment 1 = tentacular segment); body dorsoventrally flattened, tapering anteriorly and posteriorly; live specimen not observed; dorsum and everted proboscis purple in alcohol (Fig. 9A), remaining body pale yellow (Fig. 9A, B); ceratophore of median antenna and tentacular cirrophores with distinct purple pigmentation (Fig. 9C). Prostomium bilobed with wide and deep median notch; prostomial lobes slightly pronounced, anteriorly tapering (Figs. 2F and 8C). Frontal filaments distinct, basally slightly inflated, distally slender, extending from tapering prostomial lobes where medially inserted (Figs. 2F and 9C). Eyes absent. Facial tubercle trilobed, composed of three inflated oval lobes, with median lobe larger than lateral lobes (Figs. 2F and 9C). Ceratophore of median antenna massive, bulbous, with purple pigmentation, inserted medially on prostomium (near the base of anterior notch) (Figs. 2F and 9C); style of median antenna very long (longest of all appendages, reaching to beginning of segment 10), smooth and slender. Palps thick, smooth, tapering into slender tips; moderately long (extending to the beginning of segment 6). Tentaculophores large, cylindrical, equal-sized, with purple pigmentation (Fig. 9C), inserted laterally to prostomium, achaetous; all tentacular styles attached, long slender smooth, similar in form, but shorter in length (about 2/3) than style of median antenna; dorsal tentacular cirrus slightly longer than ventral tentacular cirrus. Pharynx everted, purple, with 9 pairs of equal-sized, triangular papillae distally (Fig. 9D); two pairs of dark ambercoloured jaws, with smooth margins. Second segment with elytrophores, biramous parapodia, chaetae and ventral cirri. Nine pairs of prominent, bulbous elytrophores, on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17; all elytra missing. Parapodia biramous. Notopodia reduced to elongate acicular lobe (Fig. 10A), starting on mid-dorsum as two raised ridges, extending into slender elongated acicular lobes, tip of notoacicula not penetrating epidermis; two distinct, narrow, white lines across dorsum of each segment (Fig. 9A), connecting raised ridges; dorsal tubercules not developed. Neuropodia large (Fig. 10A), approaching subtriangular to rectangular shape, with elongate slender acicular lobe, tip of neuroacicula not penetrating epidermis. Cirrigerous segments with prominent, cylindrical cirrophores, inserted basally on notopodia; styles mostly missing, 8 remaining styles very long (much longer than neuropodial acicular lobe), smooth slender, similar in form to styles of median antenna and tentacular cirri. Ventral cirri smooth, slender, tapering; present from segment 2 to last segment; inserted basally on segment 2, where very long, (slightly longer than associated neuropodia lobe); inserted medially on subsequent segments (Fig. 10A), where very short (not reaching distal margin of neuropodial lobe). Notochaetae about as slender as neurochaetae (Fig. 10B, C); few ( Two distinct white lines running through ventral side of neuropodia and ventrum of each segment (except for tentacular segment). Nephridial papillae on ventrum of segments 10, 11 and 12 small, globular, inconspicuous in other segments, present from segment 5. Reduced parapodia of segment 18 lateral to pygidium, consisting of large notopodia only. Pygidium somewhat truncated, dorsally with two large loops (Fig. 10E). Anal cirri not observed (Fig. 10E, F). Remarks. Of the Southern Ocean Macellicephala species, M. patersoni sp. nov. is most similar to M. brenesorum sp. nov. It differs from the latter species in having a massive, bulbous and pigmented ceratophore of median antenna, in lacking dorsal tubercules, in possessing two dorsal loops on the pygidium and in having neurochaetae with bidentate tips. For comparison with other known Macellicephala species, including those described in this publication, see Table 2. Molecular Information. 16S (434 bp) and 18S (676 bp) were obtained from the holotype. Based on 16S, this species was closest to Macellicephala brenesoru m sp. nov. with uncorrected 'p' distance 0.156, and distance to M. violacea was 0.166. Etymology. Macellicephala patersoni sp. nov. is named after Dr. Gordon Paterson, who recently retired from the Natural History Museum London after a long and successful career in deep-sea research with the focus on polychaete ecology and systematics. Distribution. Known only from its type locality, Pine Island Bay, Amundsen Sea, Southern Ocean, depth of 507 m.

Macellicephala macintoshi sp. nov. (Figure 2B, Figures 5, 6; Table 2.) Polynoe (Macellicephala) mirabilis in Mclntosh (1905): 59. Macellicephala mirabilis in Pettibone (1976): 10, p. 12: Fig. 3a–e. Material examined: Holotype and paratype, both specimens of McIntosh (1905), originally BMNH 1924: 7: 21: 12, South Africa (Cape of Good Hope), 540–900 m depth. Holotype retains original designation BMNH 1924: 7: 21: 12, paratype newly designated as NHMUK. 2018.25345. Description (based on holotype). Holotype 25 mm long, 6.5 mm wide including parapodia and 2 mm wide excluding parapodia; with 18 segments (segment 1 = tentacular segment); body dorsoventrally flattened, tapering anteriorly and posteriorly. Colour in alcohol deep purple dorsally (Fig. 5A) and yellow ventrally, prostomium without pigmentation, only ceratophore of median antenna with blotches of purple pigment. Prostomium bilobed with deep anterior notch; prostomial lobes moderately extended with tapering to somewhat angular anterior margin (Fig. 2B, Fig. 5B). Frontal filaments short, slender, extending from tapering lobes, medially inserted (Fig. 2B, Fig. 5B). Eyes absent. Facial tubercle large, with three distinct, inflated pads (Fig. 2B, Fig. 5D). Ceratophore of median antenna prominent, but relatively short (much shorter than prostomial lobes), cylindrical, inserted posteromedially on prostomium (near the base of anterior notch); style of median antenna missing (Fig. 2B, Fig. 5B). Palps smooth, distally tapering, relatively short (extending to segment 3). Tentaculophores prominent, of equal size, cylindrical, inserted laterally to prostomium, achaetous; styles missing (Fig. 2B, Fig. 5B). Pharynx not observed. Second segment with elytrophores, biramous parapodia, chaetae and ventral cirri. Nine pairs of prominent, bulbous elytrophores, on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17; all elytra missing. Dorsal ridges absent. Parapodia biramous. Notopodia reduced to elongate acicular lobe (Fig. 6A), tip of notoacicula not penetrating epidermis. Neuropodia large (Fig. 6A), subtriangular tapering to elongate acicular lobe, tip of neuroacicula not penetrating epidermis. Cirrigerous segments with prominent bulbous dorsal cirrophores, inserted basally on notopodia; all dorsal styles missing; small but distinct conical dorsal tubercles present (Fig. 5C). Ventral cirri smooth, tapering, present from segment 2; inserted basally on segment 2, where long (exceeding length of associated neuropodia lobe) inserted medially on subsequent segments, where extremely short. Notochaetae stouter than neurochaetae; some very long, few (about 6 present per ramus) often entirely broken off, smooth, with blunt tips; copper-coloured (Fig. 6B). Neurochaetae numerous and dense (Fig. 6C–G), upper and lower neurochaetae shorter and slender (Fig. 6G), others very long; all flattened, with extremely faint serration on both margins, tapering into pointed tip (Fig. 6C–E). Two distinct white lines running through ventral side of neuropodia and ventrum of each segment (except for tentacular segment) very prominent (Fig. 5E). Prominent globular nephridial papillae on ventrum of segments 10, 11 and 12 (Fig. 5E), inconspicuous in other segments, present from segment 5. Reduced parapodia of segment 18 lateral to pygidium, consisting of notopodia only. Pygidium rounded. Anal cirri not observed. ……continued on the next page ? Information not given in the description, neither it can be estimated from the drawings or it is stated as not observed due to poor condition of the specimen n/a - character not applicable § - re-description given by Pettibone (1976) is based on several specimens, which likely represent different species, revision is needed * Wu and Wang (1987) stated that facial tubercule is absent in M. australis, however large trilobed facial tubercule can be clearly seen depicted in their drawing (p.26, Fig. 9) # In original description by McIntosh (1885) and accompanying drawing, the frontal filaments were clearly present in this specimen, however by the time of Pettibone's re-description as well as our recent examination of this specimen, these filaments must have fallen off as they are no longer present. Based on the drawing of McIntosh, these filaments were inserted on the inner margin of anterior lobes. Remarks. Specimens assigned here to M. macintoshi sp. nov. were previously considered to belong to Macellicephala mirabilis by both McIntosh (1905) and Pettibone (1976). New species clearly differs from the holotype of M. mirabilis by having much shorter, tapering to somewhat angular prostomial lobes (Fig. 2B), deeppurple coloration of dorsum, possession of massive tri-lobed facial tubercule and extremely short ventral cirri. See also Remarks under M. mirabilis and Table 2. In addition, there appears to be confusion about the locality of specimens assigned here to M. macintoshi sp. nov. Whereas the locality stated by Pettibone (1976) for specimens accessed as BMNH: 1924: 7: 21: 12 was South Africa (off Cape Point Lighthouse, 860 m depth), the label inside the vial containing these specimens states South Africa (Cape of Good Hope, 300 –500 fathoms = 540–900 m), as included in the Material examined section in this publication. Etymology. This species is dedicated to W. C. McIntosh, who described many polychaete species, including the first species of Macellicephala, M. mirabilis (McIntosh, 1885) and who also collected the specimens upon which the description of M. macintoshi sp. nov. is based., Published as part of Neal, Lenka, Brasier, Madeleine J. & Wiklund, Helena, 2018, Six new species of Macellicephala (Annelida: Polynoidae) from the Southern Ocean and south Atlantic with re-description of type species, pp. 1-34 in Zootaxa 4455 (1) on pages 11-15, DOI: 10.11646/zootaxa.4455.1.1, http://zenodo.org/record/1456911, {"references":["Mclntosh, W. C. (1905) Marine Annelids (Polychaeta) of South Africa, Part 2. Marine Investigations in South Africa, 3, 57 - 92.","Pettibone, M. H. (1976) Revision of the Genus Macellicephala McIntosh and the Subfamily Macellicephalinae Hartmann- Schroder (Polychaeta, Polynoidae). Smithsonian Contributions to Zoology, 229, 1 - 71.","Wu, B. L. & Wang, H. Y. (1987) Two new species of Polychaeta from South Ocean. Acta Zootaxonomica Sinica, 12 (1), 23 - 29.","McIntosh, W. C. (1885) Report on the Annelida Polychaeta collected by HMS Challenger during the years 1873 - 76. Report of the Scientific Results of the Voyage of HMS Challenger 1873 - 76, 12, 1 - 554."]}

Macellicephala brenesorum sp. nov. (Figure 2E and Figure 11, 12; Table 2.) Macellicephala sp. B in Neal et al. (2017) [record]. Material examined. Holotype, NHMUK.2018.830, Pine Island Bay, Amundsen Sea, Southern Ocean, cruise JR 179, station BIO5 -EBS-1A, collected on 09/03/2008, epibenthic sledge epi-net, 74°7' 6''S, 105°50'16 W, 1478 m depth. Description (based on holotype). Medium sized species; holotype complete specimen in a reasonably good condition, 12 mm long, 1.7 mm wide excluding parapodia and 5 mm wide including parapodia, 18 segments (segment 1 = tentacular segment); body dorsoventrally flattened, tapering anteriorly and posteriorly; live specimen not observed; dorsum and everted proboscis purple in alcohol (Fig. 11A), rest of integument pale yellow (Fig. 11B). Prostomium bilobed with moderately wide and deep median notch; prostomial lobes slightly pronounced, anteriorly tapering (Figs. 2E and 11C). Frontal filaments distinct, slender, slightly enlarged basally, distally tapering (Figs. 2E and 11C). Eyes absent. Facial tubercle trilobed, composed of three inflated squarish lobes, with median lobe slightly larger than lateral lobes (Figs. 2E and 11C). Ceratophore of median antenna prominent, elongated, cylindrical, inserted medially on prostomium (near the base of anterior notch) (Figs. 2E and 11C); style of median antenna very long (extending to segment 9), smooth and slender. Palps thick, smooth, tapering into slender tips; relatively short (extending to the beginning of segment 6). Tentaculophores large (Figs. 2E and 11C), cylindrical, equal-sized, inserted laterally to prostomium, achaetous; styles still attached on left side only, long, slender, smooth, similar in form, but shorter in length than style of median antenna (about 3/4 for dorsal tentacular cirrus and ½ for ventral cirrus), dorsal cirrus longer than ventral cirrus. Pharynx everted, with 9 pairs of equal-sized triangular papillae distally (Fig. 11D); two pairs of dark amber coloured jaws with smooth margins. Second segment with elytrophores, biramous parapodia, chaetae and ventral cirri. Nine pairs of prominent, bulbous elytrophores, on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17; all elytra missing. Parapodia biramous. Notopodia reduced to elongate acicular lobe (Fig. 12A, C), starting on mid-dorsum as two raised ridges, extending into slender elongated acicular lobe, tip of notoacicula not penetrating epidermis; two narrow white lines across dorsum of each segment, connecting raised ridges. Neuropodia large (Fig. 12A), approaching subtriangular to rectangular shape, with elongate slender acicular lobe (Fig. 12B); tip of neuroacicula not penetrating epidermis. Cirrigerous segments with prominent, cylindrical cirrophores, inserted basally on notopodia; styles often missing, remaining styles very long (much longer than tip of neuropodial acicular lobe), smooth slender, similar in form to styles of median antenna and tentacular cirri. Dorsal tubercles present as distinct, conical mound (Fig. 12C). Ventral cirri smooth, slender, tapering; present from segment 2 to last segment; inserted basally on segment 2, where very long, (longer than associated neuropodia lobe); inserted medially on subsequent segments (Fig. 12A), where short (not reaching the distal margin of neuropodial lobe). Notochaetae missing (broken stumps observed). Neurochaetae numerous (Fig. 12B); all translucent, long and slender of two forms: either slightly flattened subdistally with faint serration along both margins, with blunt tips (Fig. 12D) or subdistal section with margins appearing raised, creating a depression through mid-shaft, margins faintly, but densely serrated, with pointed tip (Fig. 12D). Nephridial papillae on ventrum of segments 10, 11 and 12 prominent, globular (Fig. 11B), inconspicuous in other segments, present from segment 5. Reduced parapodia of segment 18 lateral to pygidium, consisting of notopodia only. Pygidium conical (Fig. 11E, F). Anal cirri not observed. Remarks. Of the Southern Ocean Macellicephala species, M. brenesorum sp. nov. is most similar to M. patersoni sp. nov. but differs in having smaller, cylindrical ceratophore of median antenna without pigmentation, in having distinct dorsal tubercules and in the form of pygidium and chaetae (see also Remarks under M. patersoni sp. nov.). For comparison with other known Macellicephala species, including those described in this publication, see Table 2. Molecular Information. COI (648 bp), 16S (374 bp) and 18S (1804 bp) were obtained from the holotype. Based on 16S, this species was closest to Macellicephala patersoni sp. nov. with uncorrected 'p' distance 0.156. Etymology. Macellicephala brenesorum sp. nov. is named after the first author's wonderful friends Hana and Fernando Brenes, who assisted with the image editing for this publication, while their lovely daughters Adira and Tzofia provided their very own rendition of the well-known nursery rhyme, which now goes: “There is a worm at the bottom of the ocean.” Distribution. Known only from its type locality, Pine Island Bay, Amundsen Sea, Southern Ocean, depth of 1478 m.

Macellicephala linseae sp. nov. (Figure 2H, Figure 15B, E, F and Figures 16, 17; Table 2.) Macellicephala sp. in Brasier et al. (2016) [record]. Macellicephala sp. A in Neal et al. (2017) [record]. Material examined. Holotype, NHMUK.2018.9354, Amundsen Sea, Southern Ocean, cruise JR 179, station BIO5 - EBS-2A, collected on 09/03/2008, epibenthic sledge epi-net, 73��52'46.704''S, 106��19'6.456''W, 1052 m depth. DNA vouchers (2 specimens): NHMUK.2018.9355, Amundsen Sea, Southern Ocean, cruise JR 179, station BIO5 - EBS-2A, collected on 09/03/2008, epibenthic sledge, epi-net, 73��52'46.704''S, 106��19'6.456''W, 1052 m depth; NHMUK.2018.521, Amundsen Sea, Southern Ocean, cruise JR 179, station BIO5 -EBS-3D, collected on 10/ 03/2008, epibenthic sledge, epi-net, 73��58'40.152''S, 107��25'0.372''W, 550 m. Description (based on holotype). Small to medium sized species; holotype with 18 segments (segment 1 = tentacular segment), 8.5 mm long, 1.3 mm wide excluding parapodia and 2.5 mm wide including parapodia. Live specimens not observed. Preserved specimen creamy yellow in colour (Fig. 16A���C). Prostomium bi-lobed, with a deep anterior notch; prostomial lobes short (not extended), anteriorly rounded (Fig. 16B, Fig. 2H). Frontal filaments absent. Eyes absent. Ceratophore of median antenna large, inserted in anterior notch (Figs. 2H and 16B); style of median antenna missing. Palps very long (extending to segment 9), very slender (only slightly thicker than tentacular cirri), smooth, tapering into slender tips. Tentaculophores inserted laterally to prostomium, of equal size, achaetous (Fig. 2H); only ventral tentacular styles remain attached in holotype, but dorsal styles observed in DNA voucher NHMUK.2 0 18.9355, tentacular styles smooth, very slender and very long (extending to segment 9) (Fig. 16A). Facial tubercle absent. Everted pharynx with 2 pairs of jaws and 9 pairs of small triangular papillae (Fig. 16A); each jaw with single fang and smooth margin. Nine pairs of knob-like elytrophores present on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17; elytra missing. Cirrigerous segments without dorsal tubercles; distinct dorsal cirrophores elongated, cylindrical to slightly bulbous; styles of dorsal cirri missing. Dorsal ridges appears faintly from segment 3 becoming obvious by segments 5���6, on segments 8���10 forming an oval structure, in segments anterior to segment 8 and posterior to segment 10 forming concentric structures (Fig. 16C). In posterior part of body only, similar ridges appear on parapodia of cirrigerous segments; first parapodial ridge lateral to dorsal ridge, second parapodial ridge near base of cirrophore. Parapodia biramous. Notopodia reduced to one stout acicula (Fig. 17A). Neuropodia large (Fig. 17A), elongated, subtriangular to rectangular in shape, with integument covered acicula protruding into slender tip; prechaetal and postchaetal lobes poorly developed. Ventral cirrus on segment 2 inserted basally, where very slender and long, approaching tip of neuropodial acicula lobe; inserted medially on subsequent segments where short (much shorter than tip of neuropodial lobe) (Fig. 17A). Notochaetae stout (Fig. 17A, C, D), few (only 1 to 2 per ramus observed in holotype), often broken off and missing entirely (observed in only 4 parapodia in holotype), short, straw-coloured, with distinct horizontal striation throughout length of its shaft (Fig. 17 C, D), with large rose-bush like alternating and interlocking spines on one side only, distal tip of notochaetae smooth and blunt. Neurochaetae short to very long, numerous, translucent, of two forms: either wide and flattened with shallow, but distinct denticles on both sides throughout most of their lengths, with pointed tip (Fig. 17B) or slender chaetae, with distinct alternating denticles and blunt tip (few in number and easily overlooked) (Fig. 15F, marked by arrow and Fig. 17B). Nephridial papillae globular, present at ventral junction of neuropodia and body on segments 10, 11 and 12, inconspicuous in other segments, present from segment 5. Reduced parapodia of segment 18 lateral to pygidium, consisting of notopodia only. Pygidium rounded. Anal cirri not observed. Remarks. See remarks under Macellicephala gloveri sp. nov. for further details and differentiation of M. linseae sp. nov. from similar species M. gloveri sp. nov. and M. aciculata. Molecular Information. COI and 16S were sequenced by Brasier et al. (2016), while 18S (452 bp) was obtained in this study (Table 1). Based on COI, this species was closest to Macellicephala gloveri sp. nov. with K2P distance 0.12 and uncorrected 'p' distance 0.11. Etymology. This species is named after Dr. Katrin Linse from the British Antarctic Survey, leading Antarctic researcher and the principal scientist of BIOPEARL II cruise. Distribution. Pine Island Bay, Amundsen Sea at shelf and slope depths of 550 to 1052 m., Published as part of Neal, Lenka, Brasier, Madeleine J. & Wiklund, Helena, 2018, Six new species of Macellicephala (Annelida: Polynoidae) from the Southern Ocean and south Atlantic with re-description of type species, pp. 1-34 in Zootaxa 4455 (1) on pages 27-29, DOI: 10.11646/zootaxa.4455.1.1, http://zenodo.org/record/1456911, {"references":["Brasier, M. J., Wiklund, H., Neal, L., Jeffreys, R., Linse, K., Ruhl, H. & Glover, A. G. (2016) DNA barcoding uncovers cryptic diversity in 50 % of deep-sea Antarctic polychaetes. Royal Society Open Science, 3 (11), 160432. https: // doi. org / 10.1098 / rsos. 160432","Neal, L., Linse, K., Brasier, M. J., Sherlock, E. & Glover, A. G. (2017) Comparative marine biodiversity and depth zonation in the Southern Ocean: evidence from a new large polychaete dataset from Scotia and Amundsen seas. Marine Biodiversity, 1 - 21. https: // doi. org / 10.1007 / s 12526 - 017 - 0735 - y"]}

Macellicephala mirabilis (McIntosh, 1885) (Figure 2A, Figures 3, 4; Table 2.) Polynoe (Macellicephala) mirabilis in Mclntosh (1885): 121, p.16: Fig. 1, p. 12A: Figs. 9–11 [original description]. Macellicephala mirabilis in Pettibone (1976): 10, p. 11: Fig. 1a–f [re-description]. Not Polynoe (Macellicephala) mirabilis in Mclntosh (1905): 59. Not Macellicephala mirabilis in Pettibone (1976): 10, p. 12: Fig. 3a–e. Not Macellicephala mirabilis in Monro (1936): 100. Material examined. Holotype of McIntosh (1885), BMNH 1885: 12: 1: 100, New Zealand (off North Island, blue mud), Challenger station 169, collected on 10/07/1874, 37°34'S, 179°22'E, 1280 m depth. Additional material examined. Two specimens of McIntosh (1905), BMNH 1924: 7: 21: 12, South Africa (Cape of Good Hope), 540–900 m depth. Two specimens of Monro (1936), BMNH 1936: 2: 8: 488, South Georgia (mouth of Stromness Harbour), Discovery station 144, 155– 178 m depth. Re-description. Holotype in relatively poor state, but many characters observable; specimen complete but now in two fragments (Fig. 3A, B) as a result of previous examinations, chaetae mostly broken off, all elytra missing. Holotype 25 mm long, 6 mm wide including parapodia and 4 mm wide excluding parapodia; with 18 segments (segment 1 = tentacular segment); body dorsoventrally flattened, tapering anteriorly and posteriorly; yellow in alcohol. Prostomium bilobed with deep anterior notch; prostomial lobes pronounced, greatly extended, with angular (truncated) anterior margins (Fig. 2A, Fig. 3C). Frontal filaments now missing, but once present according to McIntosh (1885) as slender, elongated filaments, inserted internally on the margin of truncated prostomial lobes. Eyes absent. Facial tubercle consisting of two disconnected inflated pads, each medial to bases of palps. Ceratophore of median antenna very long (approaching anterior margin of prostomial lobes), cylindrical, inserted posteromedially on prostomium (near base of anterior notch) (Fig. 2A, Fig. 3C); style of median antenna smooth, slender, tapering and long (extending to segment 5). Palps shortest and thickest of head appendages (extending to about segment 3), tapered, smooth. Tentaculophores prominent, of equal size, cylindrical, inserted laterally to prostomium, achaetous; styles mostly missing, only style of a ventral cirrus present (on left side), smooth, very slender and long (longer than palps but shorter than style of median antenna) (Fig. 2A, Fig. 3C). Pharynx not observed. Second segment with elytrophores, biramous parapodia, chaetae and ventral cirri. Nine pairs of prominent, bulbous elytrophores, on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17; all elytra missing. Dorsal ridges absent. Parapodia biramous. Notopodia reduced to elongate acicular lobe, tip of notoacicula not penetrating epidermis (Fig. 4A). neuropodial large (Fig. 4A), subtriangular and tapering to elongate acicular lobe, tip of neuroacicula not penetrating epidermis. Cirrigerous segments with prominent, bulbous dorsal cirrophores, inserted basally on notopodia; all dorsal styles now missing, but once present according to McIntosh (1885) as slender, smooth, cirriform appendages, far exceeding length of adjacent neuropodial; small, but distinct conical dorsal tubercles present. Ventral cirri smooth, tapering, present from segment 2; inserted basally on segment 2, where very long, about 1.5 times length of associated neuropodial lobe; inserted medially on subsequent segments, where short (not reaching the distal margin of neuropodial l lobe). Notochaetae stouter than neurochaetae (Fig. 4B), short to very long, few (about 7 present per ramus) often broken off entirely, smooth, with blunt tips. Neurochaetae numerous, upper and lower neurochaetae shorter, others very long; two forms present: either flattened, with only faint denticulation of each side (Fig. 4C) or with distinct spines, spines moderately separated (Fig. 4D, E); both forms tapering into sharp tip. Two distinct white lines running through ventral side of neuropodia and ventrum of each segment (except for tentacular segment) (Fig. 3D). Nephridial papillae of segments 10, 11 and 12 prominent (Fig. 3D), inconspicuous in other segments, present from segment 5. Reduced parapodia of segment 18 lateral to pygidium, consisting of notopodia only. Pygidium rounded. Anal cirri not observed (Fig. 3E). Remarks. During the examination of Macellicephala specimens collected as part of this study, several inconsistencies emerged with regards to the revision of the genus carried out by Pettibone (1976). Given that Macellicephala mirabilis (McIntosh, 1885) is the type species of Macellicephala and this genus is in turn the type genus of Macellicephalinae, it is important to clarify the definition of Macellicephala mirabilis. Pettibone (1976) based her re-description of M. mirabilis on the following specimens found in the collections of the NHM London: holotype of McIntosh (1885), BMNH 1885: 12: 1: 100; two specimens of McIntosh (1905), BMNH 1924: 7: 21: 12 (see M. macintoshi sp. nov.) and two specimens of Monro (1936), BMNH 1936: 2: 8: 488. The material above was re-examined as part of this study and the definition of Macellicephala mirabilis is here restricted to characters derived from the holotype BMNH 1885: 12: 1: 100, which was described in detail by McIntosh (1885). This form has very extended, anteriorly angular (truncated) prostomial lobes (Fig. 2A) rather than shorter, rounded or tapering form of prostomial lobes as seen in other species of Macellicephala (see Fig. 2 for comparison). The description and drawing provided by McIntosh (1885) clearly depicted slender elongated frontal filaments and dorsal cirri, which have since fallen off and were therefore not observed by Pettibone (1976) or in our examination. Papillation medial to bases of elytrophores and dorsal cirrophores reported by Pettibone (1976) was not observed. For a full comparison of all valid Macellicephala species based on examination of material presented in this study and published literature for the others see Table 2. Distribution. Known only from its type locality: New Zealand, off North Island, 37°34'S, 179°22'E, 1280 m depth., Published as part of Neal, Lenka, Brasier, Madeleine J. & Wiklund, Helena, 2018, Six new species of Macellicephala (Annelida: Polynoidae) from the Southern Ocean and south Atlantic with re-description of type species, pp. 1-34 in Zootaxa 4455 (1) on pages 7-10, DOI: 10.11646/zootaxa.4455.1.1, http://zenodo.org/record/1456911, {"references":["McIntosh, W. C. (1885) Report on the Annelida Polychaeta collected by HMS Challenger during the years 1873 - 76. Report of the Scientific Results of the Voyage of HMS Challenger 1873 - 76, 12, 1 - 554.","Pettibone, M. H. (1976) Revision of the Genus Macellicephala McIntosh and the Subfamily Macellicephalinae Hartmann- Schroder (Polychaeta, Polynoidae). Smithsonian Contributions to Zoology, 229, 1 - 71.","Mclntosh, W. C. (1905) Marine Annelids (Polychaeta) of South Africa, Part 2. Marine Investigations in South Africa, 3, 57 - 92.","Monro, C. C. A. (1936) Polychaete Worms, II. Discovery Reports, 12, 59 - 198."]}