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Deep-sea ophiuroids from western Mexico have been documented since 1899, but mostly by non-Mexican expeditions. TALUD is a Mexican project designed to study the deep-sea fauna from Mexico. As part of it, the present contribution provides for the first time detailed information about the taxonomy and distribution, as well as images, of deep-sea ophiuroids from western Mexico, representing a useful taxonomic identification tool for Ophiuroidea from the eastern Pacific. A total of 38 species of ophiuroid (35 identified at species level, one at genus level, and two as confer) were collected from 83 stations located at 123‒2,309 m depth. At a regional scale, several new species records are presented: six for western Baja California, five for western Baja California Sur, two for the Gulf of California, four for Jalisco, 14 for Colima, and five for Guerrero. Geographic (six) and bathymetric (seven) distribution ranges of species are extended. An updated list of deep-sea ophiuroids (61 species) from western Mexico is provided together with an identification key to species collected during this survey. In addition, nine records of deep-sea ophiuroids for the Mexican Pacific are unproven, doubtful or invalid. We corroborated the presence of Ophiacantha eurypoma and Ophiacantha pacifica in the study area and added Amphiura gymnogastra as the first record for Mexico. We propose to transfer Ophiacantha phragma to Ophiolimna on account of it having both granules and spines on the dorsal disc and striated arm plates. TALUD cruises collected 57 % of the total deep-sea species known to occur off Mexico, making it the most important survey of deep-sea Ophiuroidea carried out in western Mexico to date.

Ophiacantha diplasia H.L. Clark, 1911 Fig. 8G‒L Ophiacantha diplasia H.L. Clark, 1911: 209‒211, fig. 97a‒c.— Boolotian & Leighton 1966: 7‒8, fig. 30.— Hendler 1996: 155‒157, fig. 7.16.— Lambert & Austin 2007: 78‒79, fig. 32‒33. Ophiophthalmus diplasia. Kyte 1982: 508. Material examined. 56 individuals at five stations. TALUD X, Sta. 4, 1 ind. (ICML-EMU-11181-A). TALUD XIV, Sta. 1, 1 ind. (ICML-EMU-11180); Sta. 20, 1 ind. (ICML-EMU-11181-B). TALUD XV, Sta. 1, 12 ind. (ICML-EMU-11183) and 4 ind. (ICML-EMU-11949); Sta. 23, 34 ind. (ICML-EMU-11182) and 3 ind. (ICML-EMU-11673). Comparative material. Ophiacantha diplasia H.L. Clark, 1911, holotype, 1 ind.: USNM 24647. Paratypes, 79 ind.: MCZ OPH-3198, MCZ OPH-3199, MCZ OPH-3416, MCZ OPH-3417, MCZ OPH-3418, USNM 25647, USNM 26000, USNM 26247, USNM 26248, USNM 26814, USNM 26927, USNM 26987, USNM 27091, USNM 27215, USNM 27216 (Supplementary file 2). Description (ICML-EMU-11183). DD = 10 mm. Disc circular. Dorsal disc covered by separated granules, those on the margin longer. Primary plates not evident. RS oval, separated (Fig. 8G). Ventral interradii covered by imbricated scales and some granules distally (Fig. 8H). OSh broader than long, diamond-shape with rounded edges. Madreporite with a rounded depression. AdSh longer than broad, slender, meeting in front of OSh. Jaws bearing six papillae at each side; AdShSp elongated, longer than rest; 2AdShSp elongated; LOPa three, similar in shape to 2AdShSp; IPa pointed (Fig. 8I). Arms gradually narrowing distally. First DAP covered by granules; subsequent DAP as long as broad, rhombic, meeting (Fig. 8J). VAP slightly broader than long, pentagonal, slightly separated from each other. LAP with 6‒7 ArSp, large (approximately 2.5 arm segments in length), smooth, dorsalmost the longest. Tentacle pores with two oval TSc, abradial much longer (Fig. 8K). Color pattern in dorsal disc and arms light brown (Fig. 8G, J), beige in ventral view (ethanol preservation) (Fig. 8H). Habitat and distribution. British Columbia, Canada, Oregon and California, USA, and Mexico (H.L. Clark 1911; Lambert & Austin, 2007; Granja-Fernández et al. 2015); 71‒ 1,408 m depth (Maluf 1988; Hendler 1996), sandy and rocky substrates, coral, death coral, and sponges (H.L. Clark 1911). The material examined was collected off western Baja California Sur and in the Gulf of California; 208‒850 m depth. Remarks. Ophiacantha diplasia is highly variable in its external morphology (H.L. Clark 1911; Hendler 1996). The revision of the TALUD specimens and the type material corroborate this. The following morphological plasticity was observed in the examined specimens: 1) variability in oral shields shape, 2) different thickness of adoral shields (slender vs. broad), 3) jaws with up to 7‒8 papillae and presence of 1‒3 IPa, 4) small specimens (DD Ophiacantha diplasia had been transferred to the genus Ophiophthalmus (Kyte 1982) but was subsequently returned to Ophiacantha by Hendler (1996), who suggested that Ophiophthalmus was an invalid homonym (Paterson 1985). However, the homonymy of Ophiophthalmus has been recently disproven by Nethupul et al. (2022), and this genus currently includes five species (O. cataleimmoidus (H.L. Clark, 1911), O. hylacanthus (H.L. Clark, 1911), O. normani, O. relictus (Koehler, 1904), and O. serratus Nethupul, Stöhr & Zhang, 2022) characterized by ovoid and naked RS, 3‒4 spiniform lateral oral papillae, and a short jaw. These characteristics do not coincide with O. diplasia since the latter presents round and short RS, many oral papillae, and an elongated jaw, suggesting that it belongs to the family Ophiotomidae (O’Hara et al. 2018). Previously recorded off western Baja California, in the Gulf of California, and off the Revillagigedo Islands (Granja-Fernández et al. 2015). The material from western Baja California Sur is a new distribution record for this area., Published as part of Granja-Fernández, Rebeca, Hendrickx, Michel E., Rangel-Solís, Pedro Diego & López-Pérez, Andrés, 2023, Deep-sea Ophiuroidea (Echinodermata) collected during the TALUD cruises in western Mexico, pp. 1-71 in Zootaxa 5259 (1) on pages 33-35, DOI: 10.11646/zootaxa.5259.1.1, http://zenodo.org/record/7794984, {"references":["Clark, H. L. (1911) North Pacific Ophiurans in the collection of the United States National Museum. U. S. National Museum Bulletin, 75, 1 - 302. https: // doi. org / 10.5479 / si. 03629236.75.1","Boolotian, R. A. & Leighton, D. (1966) A key to the species of Ophiuroidea (brittle stars) of the Santa Monica Bay and adjacent areas. Los Angeles County Museum Contributions in Science, 93, 1 - 20. https: // doi. org / 10.5962 / p. 241083","Hendler, G. (1996) Taxonomic atlas of the benthic fauna of the Santa Maria Basin and Western Santa Barbara Channel. Class Ophiuroidea. Santa Barbara Museum of Natural History, 14, 113 - 179.","Lambert, P. & Austin, W. (2007) Brittle stars, sea urchins and feather stars of British Columbia, Southeast Alaska and Puget Sound. Royal BC Museum Handbook, Victoria, 150 pp.","Kyte, M. A. (1982) Ophiacantha abyssa, a new species, and Ophiophthalmus displasia (Clark), a suggested new combination in the ophiuroid family Ophicanthidae (Echinodermata: Ophiuroidea) from off Oregon, U. S. A. Proceedings of the Biological Society of Washington, 95 (3), 505 - 508.","Granja-Fernandez, R., Herrero-Perezrul, M. D., Lopez-Perez, R. A., Hernandez-Morales, A. & Rangel-Solis, P. D. (2015) A literature review of the Ophiuroidea (Echinodermata) from the Pacific coast of Mexico. Revista de Biologia Tropical, 63 (2), 37 - 47.","Maluf, L. Y. (1988) Composition and distribution of the central Eastern Pacific Echinoderms. Natural History Museum of Los Angeles County, Technical Report, 2, 1 - 306.","Lu ¨ tken, C. F. &. Mortensen, T. (1899) The Ophiuridae. Memoirs of the Museum of Comparative Zoology at Harvard College, 23 (2), 93 - 208.","Stohr, S., O'Hara, T. & Thuy, B. (2022) World Ophiuroidea database. Available from: http: // marinespecies. org / aphia. php? p = search (accessed 15 April 2022)","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History) Zoology, 49 (1), 1 - 162.","Nethupul, H., Stohr, S. & Zhang, H. (2022) Review of Ophioplinthaca Verrill, 1899 (Echinodermata, Ophiuroidea, Ophiacanthidae), description of new species in Ophioplinthaca and Ophiophthalmus, and new records from the Northwest Pacific and the South China Sea. ZooKeys, 1099, 155 - 202. https: // doi. org / 10.3897 / zookeys. 1099.76479","Koehler, R. (1904) Ophiures de l'expedition du Siboga. Part 1. Ophiures de mer profonde. In: Weber, M., Siboga Expeditie. 45 a. M. E. J. Brill, Leiden, pp. 1 - 176. https: // doi. org / 10.5962 / bhl. title. 11682","O'Hara, T. D., Stohr, S., Hugall, A. F., Thuy, B. & Martynov, A. (2018) Morphological diagnoses of higher taxa in Ophiuroidea (Echinodermata) in support of a new classification. European Journal of Taxonomy, 416, 1 - 35. https: // doi. org / 10.5852 / ejt. 2018.416"]}

Ophiophthalmus normani (Lyman, 1879) Fig. 12A‒F Ophiacantha normani Lyman, 1879: 58‒59, pl. 15, figs. 414‒416.—Lütken & Mortensen 1899: 170‒171, pl. 16, figs. 1‒4.— H.L. Clark 1911: 215‒217.— Boolotian & Leighton 1966: 7‒10, fig. 31.— Lambert & Austin 2007: 80‒81, figs. 34‒35. Ophiophthalmus normani. Koehler 1922: pl. 9, fig. 5‒6.— Kyte 1969a: 1738.— Hendler 2018: 212‒213, fig. 17.— Nethupul et al. 2022: 196. Material examined. 2,254 individuals at 14 stations. TALUD VIII, Sta. 3, 5 ind. (ICML-EMU-11198) and 5 ind. (ICML-EMU-11202-A); Sta. 10, 1 ind. (ICML-EMU-11199-A); Sta. 16, 2 ind. (ICML-EMU-11199-B). TALUD IX, Sta. 21B, 1 ind. (ICML-EMU-11202-B). TALUD X, Sta. 9, 412 ind. (ICML-EMU-11196); Sta. 10, 2 ind. (ICML-EMU-9015), 9 ind. (ICML-EMU-11200), 7 ind. (ICML-EMU-11201), and 941 ind. (ICML-EMU-11219); Sta. 12, 11 ind. (ICML-EMU-11197). TALUD XIII, Sta. B, 1 ind. (ICML-EMU-11203-A); Sta. 34, 3 ind. (ICML-EMU-11203-B); Sta. 37, 1 ind. (ICML-EMU-13000). TALUD XVIB, Sta. 19, 2 ind. (ICML-EMU-11205); Sta. 22, 47 ind. (ICML-EMU-11204); Sta. 23, 22 ind. (ICML-EMU-11206); Sta. 27, 19 ind. (ICML-EMU-11207), 54 ind. (ICML-EMU-11208), 704 ind. (ICML-EMU-11223), and 5 ind. (ICML-EMU-11688). Comparative material. Ophiacantha normani Lyman, 1879, syntypes, 4 ind.: MCZ OPH-1971 (Supplementary file 2). Description (ICML-EMU-11219). DD = 16 mm. Disc circular. Dorsal disc covered by scales and scattered granules. Primary plates not evident. RS oval, separated (Fig. 12A). Ventral interradii covered by scattered granules, longer than dorsal granules. Genital slits with numerous imbricated scales (Fig. 12B). OSh broader than long, slender, diamond-shaped with rounded edges. Madreporite with a rounded depression. AdSh longer than broad, slender, curved, separated from each other. Jaws bearing three papillae at each side; AdShSp elongated, pointed; 2AdShSp similar in shape to AdShSp; IPa similar to AdShSp and 2AdShSp but with widened base. vT pointed, wider than IPa (Fig. 12C). Arms gradually narrowing distally. DAP broader than long, fan-shaped, distal edge with a conspicuous row of pointed granules, meeting on the first segments and separated distally (Fig. 12D). VAP slightly broader than long, pentagonal with a distal notch, separated from each other. LAP with four ArSp, large (approximately three arm segments in length), smooth, dorsalmost the longest. Tentacle pores with one pointed TSc (Fig. 12E). Color pattern brown (ethanol preservation) (Fig. 12A‒F). Habitat and distribution. Japan, the Okhotsk Sea, the Bering Sea, Alaska, USA, Mexico, Costa Rica, and Peru (Lyman 1879; Lambert & Austin 2007; Granja-Fernández et al. 2015; Granja-Fernández & Hooker 2020); 37‒ 3,000 m depth (Lambert & Austin 2007), muddy substrates (Lütken & Mortensen 1899). The material examined was collected off western Baja California and in the Gulf of California; 465‒ 2,195 m depth. Remarks. Ophiophthalmus normani is easily identifiable by its DAP with a conspicuous row of pointed granules on the distal edge, and its disc with scales and granules (except on the radial shields)., Published as part of Granja-Fernández, Rebeca, Hendrickx, Michel E., Rangel-Solís, Pedro Diego & López-Pérez, Andrés, 2023, Deep-sea Ophiuroidea (Echinodermata) collected during the TALUD cruises in western Mexico, pp. 1-71 in Zootaxa 5259 (1) on pages 42-43, DOI: 10.11646/zootaxa.5259.1.1, http://zenodo.org/record/7794984, {"references":["Lyman, T. (1879) Ophiuridae and Astrophytidae of the \" Challenger \" expedition. Part II. Bulletin of the Museum of Comparative Zoology at Harvard College, 6 (2), 17 - 83.","Lu ¨ tken, C. F. &. Mortensen, T. (1899) The Ophiuridae. Memoirs of the Museum of Comparative Zoology at Harvard College, 23 (2), 93 - 208.","Clark, H. L. (1911) North Pacific Ophiurans in the collection of the United States National Museum. U. S. National Museum Bulletin, 75, 1 - 302. https: // doi. org / 10.5479 / si. 03629236.75.1","Boolotian, R. A. & Leighton, D. (1966) A key to the species of Ophiuroidea (brittle stars) of the Santa Monica Bay and adjacent areas. Los Angeles County Museum Contributions in Science, 93, 1 - 20. https: // doi. org / 10.5962 / p. 241083","Lambert, P. & Austin, W. (2007) Brittle stars, sea urchins and feather stars of British Columbia, Southeast Alaska and Puget Sound. Royal BC Museum Handbook, Victoria, 150 pp.","Koehler, R. (1922) Ophiurans of the Philippine Seas and adjacent waters. Bulletin of the United States National Museum, 100, 1 - 486. https: // doi. org / 10.5962 / bhl. title. 32917","Kyte, M. A. (1969 a) A synopsis and key to the recent Ophiuroidea of Washington State and Southern British Columbia. Journal of the Fisheries Research Board of Canada, 26 (7), 1727 - 1741. https: // doi. org / 10.1139 / f 69 - 160","Hendler, G. (2018) Armed to the teeth: a new paradigm for the buccal skeleton of brittle stars (Echinodermata: Ophiuroidea). Contribution in Science, 526, 189 - 311. https: // doi. org / 10.5962 / p. 324539","Nethupul, H., Stohr, S. & Zhang, H. (2022) Review of Ophioplinthaca Verrill, 1899 (Echinodermata, Ophiuroidea, Ophiacanthidae), description of new species in Ophioplinthaca and Ophiophthalmus, and new records from the Northwest Pacific and the South China Sea. ZooKeys, 1099, 155 - 202. https: // doi. org / 10.3897 / zookeys. 1099.76479","Granja-Fernandez, R., Herrero-Perezrul, M. D., Lopez-Perez, R. A., Hernandez-Morales, A. & Rangel-Solis, P. D. (2015) A literature review of the Ophiuroidea (Echinodermata) from the Pacific coast of Mexico. Revista de Biologia Tropical, 63 (2), 37 - 47.","Granja-Fernandez, R. & Hooker, Y. (2020). Revisiting the diversity and distribution of the ophiuroids (Echinodermata: Ophiuroidea) from Peru. Zootaxa, 4766 (4), 539 - 556. https: // doi. org / 10.11646 / zootaxa. 4766.4.2"]}

Ophiacantha pacifica Lütken & Mortensen, 1899 Fig. 10A‒F Ophiacantha pacifica Lütken & Mortensen, 1899: 166‒167, pl. 15, figs. 4‒6, pl. 16, fig. 11.— Stöhr & O’Hara 2021: 520‒523, fig. 4a‒d. Material examined. 622 individuals at seven stations. TALUD VIII, Sta. 11, 9 ind. (ICML-EMU-11193-A); Sta. 22, 28 ind. (ICML-EMU-11193-B). TALUD IX, Sta. 14, 3 ind. (ICML-EMU-11192-A); Sta. 15, 1 ind. (ICML-EMU-11192-B); Sta. 22, 8 ind. (ICML-EMU-9013-A) and 1 ind. (ICML-EMU-9013-B). TALUD XII, Sta. 27, 6 ind. (ICML-EMU-11194). TALUD XIII, Sta. 37, 561 ind. (ICML-EMU-11195) and 5 ind. (ICML-EMU-11675). Comparative material. Syntypes, 28 ind.: MCZ OPH-1972, MCZ OPH-2199, USNM 19559 (Supplementary file 2). Description (ICML-EMU-11195). DD = 7 mm. Disc pentagonal, flat. Dorsal disc densely covered by slender multifid spines. Primary plates not evident. RS longer than broad, slender, covered by scales and multifid spines, very conspicuous distally (Fig. 10A). Ventral interradii covered by scales and spines similar to those on the dorsal side (Fig. 10B). OSh broader than long, diamond-shape. Madreporite larger than OSh. AdSh longer than broad, larger than oral OSh, almost meeting or meeting in front of OSh. Jaws bearing 3‒4 erected, lanceolate papillae at each side; AdShSp pointed; LOPa 1‒2 similar in shape to AdShSp; IPa lanceolate, pointed. vT shortest than oral papillae (Fig. 10C). Arms slender. DAP almost as long as broad, triangular with rounded edges, separated from each other (Fig. 10D). VAP broader than long, pentagonal with rounded edges, separated from each other. LAP with five ArSp, large (almost one arm segment in length), slender, smooth, blunt, dorsalmost much largest. One pointed TSc, shorter than VAP, size diminishes distally (Fig. 10E). Color pattern brown dorsally and beige ventrally (ethanol preservation) (Fig. 10A‒F). Habitat and distribution. Southern California, USA, Mexico, and Ecuador; 362‒ 2,877 m depth, muddy and sandy substrates (Maluf 1988; Hendrickx 2012a; See Remarks).The material examined was collected in the southern Gulf of California; 920‒ 2,309 m depth. Remarks. According to the examination of the type material and the TALUD samples, specimens of Ophiacantha pacifica present: 1) pentagonal or rounded disc, 2) radial shields partially covered by multifid spines or naked, and 3) larger individuals (DD> 10 mm) with four oral papillae at each side of a jaw as well as up to six arm spines. Additional variations were observed by Stöhr & O’Hara (2021), who suggested that O. pacifica belongs to a species complex conformed by Ophiacantha bathybia H.L. Clark, 1911, Ophiacantha cosmica Lyman, 1878, and Ophiacantha sociabilis Koehler, 1897. Ophiacantha pacifica was tentatively recorded in Mexico by Hendrickx (2012a) and Granja-Fernández et al. (2015); its presence in Mexican waters is hereby confirmed (Gulf of California)., Published as part of Granja-Fernández, Rebeca, Hendrickx, Michel E., Rangel-Solís, Pedro Diego & López-Pérez, Andrés, 2023, Deep-sea Ophiuroidea (Echinodermata) collected during the TALUD cruises in western Mexico, pp. 1-71 in Zootaxa 5259 (1) on pages 37-39, DOI: 10.11646/zootaxa.5259.1.1, http://zenodo.org/record/7794984, {"references":["Lu ¨ tken, C. F. &. Mortensen, T. (1899) The Ophiuridae. Memoirs of the Museum of Comparative Zoology at Harvard College, 23 (2), 93 - 208.","Stohr, S. & O'Hara, T. D. (2021) Deep-sea Ophiuroidea (Echinodermata) from the Danish Galathea II Expedition, 1950 - 52, with taxonomic revisions. Zootaxa, 4963 (3), 505 - 529. https: // doi. org / 10.11646 / zootaxa. 4963.3.6","Clark, H. L. (1917) Reports on the scientific results of the expedition to the Eastern Tropical Pacific in charge of Alexander Agassiz, by the U. S. Fish Commission Steamer \" Albatross \" from October, 1904, to March, 1905, Lieut. Commander L. M. Garrett U. S. N., Commanding. XXX. Ophiuroidea. Bulletin of the Museum of Comparative Zoology at Harvard College, 61 (12), 429 - 453.","Maluf, L. Y. (1988) Composition and distribution of the central Eastern Pacific Echinoderms. Natural History Museum of Los Angeles County, Technical Report, 2, 1 - 306.","Hendrickx, M. E. (2012 a) Listado sistematico de los equinodermos de aguas profundas del Pacifico mexicano. In: Zamorano, P., Hendrickx, M. E. & Caso, M. (Eds.), Biodiversidad y comunidades del talud continental del Pacifico mexicano. Secretaria del Medio Ambiente y Recursos Naturales (SEMARNAT), Instituto Nacional de Ecologia (INE), Mexico, D. F., pp. 373 - 395.","Clark, H. L. (1911) North Pacific Ophiurans in the collection of the United States National Museum. U. S. National Museum Bulletin, 75, 1 - 302. https: // doi. org / 10.5479 / si. 03629236.75.1","Lyman, T. (1878) Ophiuridae and Astrophytidae of the \" Challenger \" expedition. Part I. Bulletin of the Museum of Comparative Zoology at Harvard College, 5 (7), 65 - 168.","Koehler, R. (1897) Echinodermes recueillis par \" l'Investigator \" dans l'Ocean Indien. I. Les Ophiures de mer profonde. Annales des Sciences Naturelles Zoologie, series 8, 4, 277 - 372.","Granja-Fernandez, R., Herrero-Perezrul, M. D., Lopez-Perez, R. A., Hernandez-Morales, A. & Rangel-Solis, P. D. (2015) A literature review of the Ophiuroidea (Echinodermata) from the Pacific coast of Mexico. Revista de Biologia Tropical, 63 (2), 37 - 47."]}

Ophiacantha costata Lütken & Mortensen, 1899 Fig. 8A‒F Ophiacantha costata Lütken & Mortensen, 1899: 172‒173, pl. 16, fig. 10, pl. 17, figs. 4‒6. Material examined. Two individuals at two stations. TALUD VIII, Sta. 11, 1 ind. (ICML-EMU-11695); TALUD XII, Sta. 28, 1 ind. (ICML-EMU-11700). Comparative material. Syntypes, 9 ind.: MCZ OPH-1941, MNHN 2013-10259, USNM 19573, USNM 19574 (Supplementary file 2). Description (ICML-EMU-11700). DD = 6 mm. Disc interadii deeply indented. Dorsal disc covered by scales and short multifid spines. Primary plates not evident. RS slender, elongated, covered by multifid spines (Fig. 8A). Ventral interradii very reduced, covered by imbricated scales and spines similar to those on the dorsal side (Fig. 8B). OSh broader than long, diamond-shape with distal rounded edge. Madreporite swollen. AdSh longer than broad, semilunar; almost meeting or meeting in front of OSh. Jaws bearing five papillae at each side; AdShSp lanceolate; LOPa three, lanceolate, first the longest of all oral papillae, the rest slender; IPa pointed. vT longer than oral papillae (Fig. 8C). Arms slender, gradually narrowing distally. First DAP reduced, covered by short multifid spines; subsequent DAP slightly longer than broad, bell-shaped with rounded edges; separated from each other by lateral plates (Fig. 8D). VAP broader than long, pentagonal, separated from each other. LAP with six ArSp, large (approximately 1.5 arm segment in length), serrated, dorsalmost the longest and ventralmost the shortest. One elongated, pointed TSc (Fig. 8E). Color pattern beige (ethanol preservation) (Fig. 8A‒F). Habitat and distribution. California, USA, Mexico, and Panama; 733‒ 1,271 m depth, sandy substrates (Lütken & Mortensen 1899; Maluf 1988). The material examined was collected in the southern Gulf of California and off Colima; 920‒ 1,106 m depth. Remarks. The widely open genital slits (Fig. 8B) in our examined material can be an artifact of preservation or a stress reaction to the fixing process (pers. comm. Sabine Stöhr, 2022). Previously recorded in the Gulf of California and off Marias Islands (Granja-Fernández et al. 2015). The examined material collected off Colima corresponds to a new distribution record for this area and the southernmost record in the Mexican Pacific.

Ophiolimna phragma (Ziesenhenne, 1940) new combination Fig. 11G‒L Ophiacantha phragma Ziesenhenne, 1940: 11‒13, pl. 2 figs. 4‒6.— Boolotian & Leighton 1966: 7, 10, fig. 29. Material examined. One individual at one station. TALUD XVIB, Sta. 28, 1 ind. (ICML-EMU-11682). Comparative material. Ophiacantha phragma Ziesenhenne, 1940, holotype, 1 ind.: LACM 597.7. Paratypes, 23 ind.: LACM 597.3, LACM 597.6, LACM 597.8, LACM 597.9, LACM 597.10, LACM 597.11, LACM 597.12, LACM 597.13, LACM 597.14, LACM 597.15, LACM 597.16 (Supplementary file 2). Description (ICML-EMU-11682). DD = 6 mm. Disc rounded. Dorsal disc densely covered by granules and scattered elongated spines. Primary plates not evident. RS covered by granules and spines (Fig. 11G). Ventral interradii covered by granules, smaller than dorsal granules (Fig. 11H). OSh broader than long, triangular with rounded edges, granules distally. Madreporite larger than OSh, with a central rounded depression. AdSh longer than broad, very slender, meeting in front of OSh. Jaws bearing 5‒6 papillae at each side; AdShSp rounded; LOPa 3‒4, first LOPa similar in shape to AdShSp but smaller, rest elongated and pointed; IPa elongated, pointed. vT wider than oral papillae (Fig. 11I). Arms slender. First DAP covered by granules; subsequent DAP longer than broad, hexagonal with rounded distal edge, meeting. Longitudinal swollen keel along DAP (Fig. 11J). First VAP broader than long, rhombic, smaller than rest. Second to fourth VAP broader than long; subsequent VAP longer than broad, triangular with concave distal edge, meeting excepting distally. LAP striated. LAP with 6‒7 ArSp, large (almost two arm segments in length), slender, blunt, dorsalmost largest, ventralmost shortest. First 2‒3 tentacle pores with two TSc; subsequent pores with one oval TSc (Fig. 11K). Color pattern in dorsal disc and arms brown (Fig. 11G, J, L), ventral side beige (ethanol preservation) (Fig. 11H). Habitat and distribution. California, USA, Mexico, Costa Rica, Panama, Colombia, Ecuador, and the Galapagos Islands; 13‒ 1,532 m depth, muddy and sandy substrates, gravel, and coralline bottoms (Ziesenhenne 1940; Solís-Marín et al. 2013; see Remarks). The material examined was collected off western Baja California; 1,461 ‒1,532 m depth. Remarks. The genus Ophiacantha is characterized by uncovered bar-like radial shields (Matsumoto 1917), but Ophiacantha phragma, as originally described, has radial shields covered by granules and spines. Our revision of O. phragma, including a detailed examination of the holotype and paratypes, clearly indicated that it belongs to Ophiolimna due to the following characters: 1) a disc densely covered with numerous granules and few spines, 2) distalmost papillae broad, rounded, and operculiform, 3) the junction area of the adoral shields and the edges of the oral shield covered by granules, 4) a single broad tentacle scale, and 5) striated lateral arm plates (O’Hara & Stöhr 2006; Martynov 2010). Therefore, it is herein proposed to assign this species to the genus Ophiolimna (new combination). Ophiolimna phragma is very similar to O. bairdi, but the following characteristics help to easily distinguish them from one another (comparing specimens with a similar size, DD = 6 mm): 1) dorsal arm plates triangular, as long as wide in O. bairdi vs. hexagonal, longer than wide (2‒3 times) in O. phragma, 2) adoral shields conspicuous in O. bairdi vs. inconspicuous, hardly noticeable in O. phragma, 3) distalmost oral papilla of much larger size in O. bairdi, and 4) one tentacle scale in O. bairdi vs. first 1‒8 segments with two tentacle scales and then with one tentacle scale in O. phragma. The genus Ophiolimna currently includes seven species (Stöhr et al. 2022) of which O. bairdi and O. phragma are the two representatives for the eastern tropical Pacific. The previously deepest record for O. phragma was from 644 m depth (Maluf 1988; as Ophiacantha phragma), but during the TALUD cruises one specimen was collected as deep as 1,532 m., Published as part of Granja-Fernández, Rebeca, Hendrickx, Michel E., Rangel-Solís, Pedro Diego & López-Pérez, Andrés, 2023, Deep-sea Ophiuroidea (Echinodermata) collected during the TALUD cruises in western Mexico, pp. 1-71 in Zootaxa 5259 (1) on pages 40-42, DOI: 10.11646/zootaxa.5259.1.1, http://zenodo.org/record/7794984, {"references":["Ziesenhenne, F. C. (1940) New Ophiurans of the Allan Hancock Pacific Expeditions. Allan Hancock Pacific Expeditions, 8 (2), 9 - 52.","Boolotian, R. A. & Leighton, D. (1966) A key to the species of Ophiuroidea (brittle stars) of the Santa Monica Bay and adjacent areas. Los Angeles County Museum Contributions in Science, 93, 1 - 20. https: // doi. org / 10.5962 / p. 241083","Lyman, T. (1883) Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Caribbean Sea (1878 - 79), and on the east coast of the United States, during the summer of 1880, by the U. S. coast survey steamer \" Blake \", commander J. R. Bartlett, U. S. N., commanding. XX. Report on the Ophiuroidea. Bulletin of the Museum of Comparative Zoology at Harvard College, 10 (6), 227 - 287.","Solis-Marin, F. A., Alvarado, J. J., Abreu-Perez, M., Aguilera, O., Ali, J., Bacallado-Aranega, J. J., Barraza, E., Benavides-Serrato, M., Benitez-Villalobos, F., Betancourt-Fernandez, L., Borges, M., Brandt, M., Brogger, M. I., Borrero-Perez, G. H., Buitron- Sanchez, B. E., Campos, L. S., Cantera, J., Clemente, S., Cohen-Renjifo, M., Coppard, S., Costa-Lotufo, L. V., del Valle- Garcia, R., Diaz, Y., Diaz de Vivar, M. E., Diaz-Martinez, J. P., Duran-Gonzales, A., Ephera, L., Escolar, M., Francisco, V., Freire, C. A., Garcia-Arraras, J. E., Gil, D. G., Hadel, V. F., Hearn, A., Hernandez, J. C., Hernandez-Delgado, E. A., Herrera- Moreno, A., Herrero-Perezrul, M. D., Hooker, Y., Honey-Escandon, M. B. I., Lodeiros, C., Luzuriaga, M., Manso, C. L. C., Martin, A., Martinez, M. I., Martinez, S., Moro-Abad, L., Mutschke, E., Navarro, J. C., Neira, R., Noriega, N., Palleiro- Nayar, J. S., Perez, A. F., Perez-Ruzfa, A., Prieto-Rios, E., Reyes, J., Rodriguez, R., Rubilar, T., Sancho-Mejia, T., Sangil, C., Silva, J. R. M. C., Sonnenholzner, J. I., Ventura, C. R., Tablado, A., Tavares, Y., Tiago, C. G., Tuya, F. & Williams, S. M. (2013) Appendix. In: Alvarado-Barrientos, J. J. & Solis-Marin, F. A. (Eds.), Echinoderm research and diversity in Latin America. Springer-Verlag, Berlin, pp. 543 - 658.","Matsumoto, H. (1917) A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College of Science, Imperial University, Tokyo, 32 (2), 1 - 408.","O'Hara, T. D. & Stohr, S. (2006) Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Forges, R. & Justine, J. L. (Eds.), Tropical deep-sea benthos. Vol. 24. Memoires du Museum national d´Histoire naturelle, Paris, 193, pp. 33 - 141.","Martynov, A. (2010) Reassessment of the classification of the Ophiuroidea (Echinodermata), based on morphological characters. I. General character evaluation and delineation of the families Ophiomyxidae and Ophiacanthidae. Zootaxa, 2697 (1), 1 - 154. https: // doi. org / 10.11646 / zootaxa. 2697.1.1","Stohr, S., O'Hara, T. & Thuy, B. (2022) World Ophiuroidea database. Available from: http: // marinespecies. org / aphia. php? p = search (accessed 15 April 2022)","Maluf, L. Y. (1988) Composition and distribution of the central Eastern Pacific Echinoderms. Natural History Museum of Los Angeles County, Technical Report, 2, 1 - 306."]}

Ophiolimna bairdi (Lyman, 1883) Fig. 11A‒F Ophiacantha bairdi Lyman, 1883: 256, pl. 5, figs. 70‒72. Ophiolimna bairdi. Lütken & Mortensen 1899: 177, pl. 18, figs. 9‒13.— H.L. Clark 1911: 230‒231.— Kyte 1969a: 1738.— Paterson 1985: 60, fig. 24.— Martynov 2010: 68, figs. 13g, 28c, 44a, 81a‒b, 82a, 82d, 82g, 82j.— Martynov & Litvinova 2008: 100‒101, fig. 17a.— Lambert & Boutillier 2011: 44, fig. 30.— O’Hara & Thuy 2022: 28, fig. 6g ‒h. See Paterson (1985) and O’Hara & Thuy (2022) for other synonymous records. Material examined. 95 individuals at seven stations. TALUD VIII, Sta. 3, 11 ind. (ICML-EMU-11209); Sta. 11, 5 ind. (ICML-EMU-11210-B); Sta. 15, 10 ind. (ICML-EMU-11210-A); Sta. 22, 26 ind. (ICML-EMU-11211). TALUD XII, Sta. 26, 1 ind. (ICML-EMU-11212-B); Sta. 27, 16 ind. (ICML-EMU-11212-A). TALUD XIII, Sta. 37, 26 ind. (ICML-EMU-11213). Comparative material. Ophiacantha bairdi Lyman, 1883, holotype: MCZ OPH-1916. Paratypes, 2 ind.: MCZ OPH-1917, MNHN-IE-2013-10324 (Supplementary file 2). Description (ICML-EMU-11211). DD = 10.8 mm. Disc pentagonal, flat. Dorsal disc covered by elongated granules and few scattered elongated spines. Primary plates and RS covered by granules (Fig. 11A). Ventral interradii covered by granules similar to dorsal granules (Fig. 11B). OSh broader than long, triangular with rounded edges. Madreporite with a rounded depression. AdSh longer than broad, slender, triangular, separated from each other. Oral plate conspicuous, covered by granules projected to OSh and AdSh. Jaws bearing five papillae at each side; AdShSp rounded; LOPa three, first LOPa oval, the rest elongated, pointed; IPa very pointed, large. vT similar in appearance to IPa but shorter (Fig. 11C). Arms fragile. First DAP covered by granules; subsequent DAP slightly longer than broad, triangular with rounded edges, slightly separated from each other (Fig. 11D). VAP slightly longer than broad, pentagonal, meeting. VAP and LAP with conspicuous horizontal striations, respectively. LAP with 7‒8 ArSp, large (approximately three arm segments in length), smooth, pointed. Tentacle pores with one lanceolate TSc (Fig. 11E). Color pattern in dorsal and ventral disc and arms brown (ethanol preservation) (Fig. 11A‒F). Habitat and distribution. Widely distributed in the Atlantic and Pacific Oceans (Lambert & Boutillier 2011). In the Pacific it has been reported from Japan, the Okhotsk Sea, Alaska, USA, Mexico, Costa Rica, and Panama (Lütken & Mortensen 1899; H.L. Clark 1911; Lambert & Boutillier 2011; Granja-Fernández et al. 2015); 620‒ 2,600 m depth (Martynov 2010), muddy substrates (Lütken & Mortensen 1899). The material examined was collected in the southern Gulf of California and off Colima; 920‒ 2,200 m depth. Remarks. In the material examined, even smaller specimens (DD = 5 mm) presented the characteristic horizontal striations in the ventral and lateral arm plates but with a tuberculous appearance. Moreover, these small specimens had denser spines on the dorsal disc than larger specimens. Due to its wide geographic distribution, a thorough morphological and molecular approach is needed to elucidate whether it may be a cryptic species complex. In Mexico, Ophiolimna bairdi had previously been documented off western Baja California Sur and in the Gulf of California (Granja-Fernández et al. 2015); its presence off Colima represents a new distribution record for Mexico., Published as part of Granja-Fernández, Rebeca, Hendrickx, Michel E., Rangel-Solís, Pedro Diego & López-Pérez, Andrés, 2023, Deep-sea Ophiuroidea (Echinodermata) collected during the TALUD cruises in western Mexico, pp. 1-71 in Zootaxa 5259 (1) on page 40, DOI: 10.11646/zootaxa.5259.1.1, http://zenodo.org/record/7794984, {"references":["Lyman, T. (1883) Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Caribbean Sea (1878 - 79), and on the east coast of the United States, during the summer of 1880, by the U. S. coast survey steamer \" Blake \", commander J. R. Bartlett, U. S. N., commanding. XX. Report on the Ophiuroidea. Bulletin of the Museum of Comparative Zoology at Harvard College, 10 (6), 227 - 287.","Lu ¨ tken, C. F. &. Mortensen, T. (1899) The Ophiuridae. Memoirs of the Museum of Comparative Zoology at Harvard College, 23 (2), 93 - 208.","Clark, H. L. (1911) North Pacific Ophiurans in the collection of the United States National Museum. U. S. National Museum Bulletin, 75, 1 - 302. https: // doi. org / 10.5479 / si. 03629236.75.1","Kyte, M. A. (1969 a) A synopsis and key to the recent Ophiuroidea of Washington State and Southern British Columbia. Journal of the Fisheries Research Board of Canada, 26 (7), 1727 - 1741. https: // doi. org / 10.1139 / f 69 - 160","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History) Zoology, 49 (1), 1 - 162.","Martynov, A. (2010) Reassessment of the classification of the Ophiuroidea (Echinodermata), based on morphological characters. I. General character evaluation and delineation of the families Ophiomyxidae and Ophiacanthidae. Zootaxa, 2697 (1), 1 - 154. https: // doi. org / 10.11646 / zootaxa. 2697.1.1","Martynov, A. V. & Litvinova, N. M. (2008) Deep-water Ophiuroidea of the northern Atlantic with descriptions of three new species and taxonomic remarks on certain genera and species. Marine Biology Research, 4 (1 - 2), 76 - 111. https: // doi. org / 10.1080 / 17451000701840066","Lambert, P. & Boutillier, J. (2011) Deep-sea Echinodermata of British Columbia, Canada. Canadian Technical Report of Fisheries and Aquatic Sciences, 2929, 1 - 140.","O'Hara, T. D. & Thuy, B. (2022) Biogeography and taxonomy of Ophiuroidea (Echinodermata) from the I ˆ les Saint-Paul and Amsterdam in the southern Indian Ocean. Zootaxa, 5124 (1), 1 - 49. https: // doi. org / 10.11646 / zootaxa. 5124.1.1","Granja-Fernandez, R., Herrero-Perezrul, M. D., Lopez-Perez, R. A., Hernandez-Morales, A. & Rangel-Solis, P. D. (2015) A literature review of the Ophiuroidea (Echinodermata) from the Pacific coast of Mexico. Revista de Biologia Tropical, 63 (2), 37 - 47."]}

Deep-sea ophiuroids were collected by the manned submersible ‘Shenhaiyongshi’ from the South China Sea at depths of 500–3550 m, in 2017 to 2020. A total of 18 species were identified, including three new species and eight new records, increasing the total number of species known from the South China Sea to 304. Most of the ophiuroids recorded from the South China Sea were found in shallow waters (77.9%) and a few of them occurred only in deep water (20.4%). Three new species are described as Ophiacantha aster sp. nov., Ophiomoeris petalis sp. nov. and Ophiopristis shenhaiyongshii sp. nov. We provide comprehensive descriptions of morphological features, including characteristics of the arm skeletons, and a phylogenetic analysis based on COI and 16S sequences. Overall intraspecific and interspecific genetic distance variations among the families found in this study were 0.5% to 2.47% and 1.16% to 44.16%, respectively, along the South Pacific region to the South China Sea. Our phylogenetic analysis suggested that COI partial genes resolved the interspecies complexity in the class Ophiuroidea better than 16S partial genes. The order Euryalida had low interspecies genetic distance variation within the class Ophiuroidea. The present study suggests a high probability that species of Asteroschema and Gorgonocephalus are more widely spread around the Indo-Pacific region than previously expected.

Ophientrema scolopendrica (Lyman, 1883) Figs 20–22 Ophiacantha scolopendrica Lyman, 1883: 259. Ophiacantha leucosticta H.L. Clark, 1911: 235. Ophientrema leucosticta – Matsumoto 1917: 111. Ophientrema leucostictum – H.L. Clark 1911: 217. — Koehler 1922a: 85, pl. 8 figs 1–4, pl. 94 fig. 1. Material examined CHINA • 1 spec.; South China Sea, E of Hainan Island, seamount; 18°30.14′ N, 112°49.62′ E; depth 1400 m; 28 Jun. 2019; collection event: stn SC003; MSV Shenhaiyongshi leg.; preserved in -80°C; IDSSE EEB-SW0035 • 1 spec.; South China Sea, SE of Hainan Island, seamount; 17°27.00′ N, 111°15.00′ E; depth 1550 m; 24 Mar. 2018; collection event: stn SC018; MSV Shenhaiyongshi leg.; preserved in -80°C; GenBank: MZ198775, MZ203271; IDSSE EEB-SW0021 • 2 specs; same collection data as for preceding; IDSSE EEB-SW0036, IDSSE EEB-SW0037 • 2 specs; South China Sea, SE of Hainan Island, seamount; 17°35.80′ N, 111°02.00′ E; depth 1750 m; 3 Apr. 2018; collection event: stn SC022; MSV Shenhaiyongshi leg.; preserved in -80°C; IDSSE EEB-SW0038, IDSSE EEB-SW0039 • 1 spec.; South China Sea, SE of Hainan Island, seamount; 17°17.81′ N, 110°31.92′ E; depth 1460 m; 4 Apr. 2018; collection event: stn SC023; MSV Shenhaiyongshi leg.; preserved in -80°C; IDSSE EEB- SW0040 • 1 spec.; South China Sea, Xisha Islands, seamount; 17°06.00′ N, 110°58.20′ E; depth 1500 m; 23 Mar. 2018; collection event: stn SC017; MSV Shenhaiyongshi leg.; preserved in -80°C; GenBank: MZ198774, MZ203270; IDSSE EEB-SW0020 • 1 spec.; same collection data as for preceding; IDSSE EEB-SW0041. Description (IDSSE EEB-SW 0020) MEASUREMENTS. Disc diameter 13 mm, length of arms 80–100 mm. DiSC. Disc slightly pentagonal (Fig. 20A–B). Dorsal disc covered by thin, uncalcified, dark skin with surface of small projecting granules (Fig. 20A). Ventral disc smooth, with few or no smooth granules (Fig. 20B, E). Radial shields short, distally wider and widely separated (Fig. 21F). Distal half of radial shields uncovered, bearing few granules on outer margin but do not reach periphery of disc (Fig. 21F–G). Oral shields short, twice as wide as long and somewhat rhombic. Adoral shields short and wide, proximally meeting fully or some hardly meeting (Fig. 21A). Teeth significantly larger than oral papillae. Lateral oral papillae broad, flat, rounded, transparent, distal edges break easily (Fig. 21E). Number of lateral oral papillae varies among jaws, three per side, but some jaws have four oral papillae on one side (Fig. 21E). Genital slits conspicuous and extending from distal end of oral shield to periphery of disc (Fig. 21B). ARMS. Dorsal arm plate transversely oval with pointy corners, nearly twice as broad as long, covering only about half width of arm (Fig. 21C). First ventral arm plate transverse diamond-shaped, with rounded angles, next two plates square with convex outer margin. Beyond third ventral arm plate, arm segments nearly semicircular with slight peak, covering one third of width of arm segment (Fig. 21D–E). Tentacle scale absent on first arm segment and starts to appear from second or third arm segment (Fig. 21E). Lateral arm plates stout, forming well defined spine ridge and meeting on ventral side except on first two arm segments (Fig. 21D–F). Seven arm spines on an elevated ridge, four dorsal and three to four ventral. Dorsal arm spines often nearly two segments long, stout, nearly cylindrical and tapering to a blunt point (Fig. 21G). Ventral arm spines smaller, thorny with hook-shaped tip, with a few spiny points on their adoral or proximal side (Fig. 21H–I). Ventralmost arm spines on first few arm segments elongated and less hook-like, with rough surface but distalwards along arm developing into a short, little hyaline hook (Fig. 21I). COLOR. Dark olivaceous green on dorsal disc, light brown color on radial shield, dorsal arm spine, and dorsal and ventral arm plate; dark reddish brown on oral papillae and ventral arm spine (Fig. 20A–B). OSSiCLE MORPHOLOGY.Ventralmost arm spine short, thorny, with proximally oriented tip (Fig. 22A). Arm spine articulation well developed, with volute-shaped perforated lobe except in dorsal- and ventralmost articulations (Fig. 22B–C), with large muscle opening and small nerve opening (Fig. 22B–C). Vertebrae with short zygospondylous articulation with a broad dorsal extension of lateral muscle flanges, distally abruptly truncated, dorsal median furrow moderately expressed, and podial basins short and large (Fig. 22D–G). Middle segment of ventral vertebrae with deeply expressed furrow without oral bridge (Fig. 22F). Remarks The genus Ophientrema includes only two species, O. euphylactea (H.L. Clark, 1911) and O. scolopendrica (Lyman 1883). H.L. Clark (1911) mentioned a band of black spots on the dorsal disc of O. scolopendrica caused by tissue on the inner surface of the skin. In the present study, we examined nine specimens and all of them concurred with the description of the holotype of O. scolopendrica. However, there are some slightly different features in the color of the dorsal disc and number of lateral oral papillae, but the color of the present specimens matched the description by Koehler (1922a). Among the specimens from this study, we identified two different color patterns: 1) dark olivaceous green on the dorsal disc, light brown on radial shield, dorsal arm spine, and dorsal and ventral arm plate; 2) dark reddish brown on oral papillae and ventral arm spine, dark olivaceous green and brown on dorsal disc and bright red pink on radial shield, light brown on oral papillae, dorsal and ventral arm plate, and arm spine (Fig. 20A–D). Some specimens possessed seven oral papillae on one jaw, but when we examined our specimens and previous records, we considered this as intraspecific variation. Ophientrema euphylactea is distinguished from O. scolopendrica by the scale density on the dorsal disc and by having spiniform oral papillae (H.L. Clark 1911). Distribution 1000–2000 m depth. South China Sea, Eastern Japan, Indonesia (Gulf of Tomoni), Eastern China Sea, Tasman Sea, Madagascar (OBIS 2021). Genus Ophiurothamnus Matsumoto, 1917, Published as part of Nethupul, Hasitha, Stöhr, Sabine & Zhang, Haibin, 2022, New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach, pp. 1-95 in European Journal of Taxonomy 810 (1) on pages 39-44, DOI: 10.5852/ejt.2022.810.1723, http://zenodo.org/record/6419522, {"references":["Lyman T. 1883. Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Carribbean Sea (1878 - 79), and on the east coast of the United States, during the summer of 1880, by the U. S. coast survey steamer \" Blake \", commander J. R. Bartlett, U. S. Bulletin of the Museum of Comparative Zoology 10 (6): 227 - 287.","Clark H. L. 1911. North Pacific ophiurans in the collection of the United States National Museum. United States National Museum Bulletin 75: 1 - 302.","Matsumoto H. 1917. A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College of Science, Imperial University, Tokyo 38: 1 - 408.","Koehler R. 1922 a. Ophiurans of the Philippine seas and adjacent waters. United States National Museum Bulletin 5 (100): 1 - 480.","OBIS 2021. Ocean Biodiversity Information System. Available from www. obis. org [accessed 15 Aug. 2021]."]}

Ophiomoeris petalis sp. nov. urn:lsid:zoobank.org:act: 656A30A3-A81A-4A87-9C19-4007F194788A Figs 34–35 Diagnosis Disc with deep interradial incisions with seven lobes and ring of irregular scales bearing a few granules around centrodorsal plate and overlapping with radial shields. Seven thin arms curled under disc. Etymology The specific name is derived from the Latin word for flower petals, alluding to the shape of the disc. Material examined Holotype CHINA • South China Sea, SE of Zhongsha Islands, seamount; 13°58.65′ N, 114°52.09′ E; depth 1550 m; 25 Sep. 2020; collection event: stn SC013; MSV Shenhaiyongshi leg.; preserved in 95% ethanol; GenBank: MZ 203278; IDSSE EEB-SW0029. Paratypes CHINA • 5 specs; same collection data as for holotype; IDSSE EEB-SW0058 to EEB-SW0062. Description (holotype) MEASUREMENTS. Disc diameter 2.2 mm, heptamerous specimen. DiSC. Disc heptamerous with deep interradial incisions and a lobe above each arm, four large lobes, three smallest lobes and one intermediate lobe (signs of regeneration after fission). Arms differ in width in groups of 3, 3, 1 arms. Lobes formed by large drop-shaped radial shields, largest one a third of disc diameter in length and two to three times as long as wide (Fig. 34A–C). Radial shields distally connected, separated proximally by large triangular scales, covered by small conical granules (Fig. 34E). Center of disc sunken and covered by large, round centrodorsal plate without granules (Fig. 34A, C). Ring of irregular plates bearing a few conical granules around centrodorsal plate and overlapping with radial shields (Fig. 34A, C). Genital slits small, half as long as interradial ventral disc (Fig. 34F). Oral shields swollen, much smaller than adoral shields, as wide as long, fan-shaped with pointed proximal angle, slightly concave lateral edges and convex distal edge; size varies among radials (Fig. 34B, D, F). Adoral shields swollen, twice as wide as long, with angled, concave proximal edges of oral shield, not separating it from arm (Fig. 34F). Jaw as wide as long bearing one pointed ventralmost tooth and three spiniform lateral oral papillae, proximalmost one spine-like, other two shorter and rounded (Fig. 34F). All teeth spiniform like ventralmost tooth (Fig. 35B, D, F). ARMS. Seven thin arms, curled under disc. Dorsal arm plates fan-shaped, two times as wide as long, with convex distal edge and always separated (Fig. 34G). Ventral arm plate much wider than long on proximal segments, but reduced to small, round, thin scales, embedded in a strand of thick skin running along entire arm distally, always present along arm and always separated (Fig. 34H). Four thick, conical, smooth arm spines, two thirds arm segment in length (Fig. 34D, H). One minute tentacle scale clearly visible on proximal arm segments (Fig. 34D). COLOR. In alcohol, entire specimen creamy white. OSSiCLE MORPHOLOGY. Arm spine articulation formed by two thick, smooth, curved lobes, ventral lobe smaller than dorsal lobe, positioned at angle to distal edge of lateral plate, with large muscle opening and small nerve opening, the latter large in dorsalmost articulation. Volute-shape not well defined, absent in dorsalmost articulation, dorsal and ventral articular lobes connected but separating in ventral articulations (Fig. 35A–C). Vertebrae elongated, with streptospondylous articulation, dorsal and lateral furrows absent, middle section much lower than proximal part and distal muscle flanges, with straight ambulacral groove. Podial basins at distal end, tongue-like with round hole (Fig. 35D–F). Variations in paratypes Five heptamerous paratypes, with disc diameter ranging from 1.45 mm to 1.87 mm. All with similar morphological features as holotype, having conical granules on disc plates/scales and large, drop-shaped radial shields. Most paratypes with arms curled under disc. Remarks The oral frame arrangement and the lobe-like shape of the disc concur with the genus Ophiomoeris, which was recently transferred to Ophiacanthidae (O’Hara et al. 2018). The arm spine articulation of this genus is interpreted as a variation of the volute-shape typical of the family Ophiacanthidae. Previously only four species of Ophiomoeris were recognized and all of them are pentamerous: O. obstricta (Lyman, 1878), O. exuta Stöhr, 2011, O. nodosa (Koehler, 1905) and O. tenera (Koehler, 1897). The seven-fold symmetry is consistent in all our specimens. This is the first record of a sevenarmed (or indeed non-pentamerous) species in the genus Ophiomoeris, and this distinguishes it from all congeners. The size differences among the seven sections of the animals suggests that it is a fissiparous species. Morphological characters to differentiate species in the genus Ophiomoeris are otherwise difficult to interpret due to their high morphological variation among individuals. Taking geographic distribution into account, there may be several cryptic species complexes in the genus Ophiomoeris that can only be resolved by a molecular study (O’Hara & Stöhr 2006; Stöhr 2011). Distribution and habitat South China Sea (1550 m), found on a deep-sea seamount near the Zhongsha Islands. Order Amphilephidida O’Hara, Hugall, Thuy, Stöhr & Martynov, 2017 Suborder Gnathophiurina Matsumoto, 1915 Superfamily Ophiactoidea Ljungman, 1867 Family Ophiactidae Matsumoto, 1915 Genus Ophiactis Lütken, 1856, Published as part of Nethupul, Hasitha, Stöhr, Sabine & Zhang, Haibin, 2022, New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach, pp. 1-95 in European Journal of Taxonomy 810 (1) on pages 61-64, DOI: 10.5852/ejt.2022.810.1723, http://zenodo.org/record/6419522, {"references":["O'Hara T. D., Stohr S., Hugall A. F., Thuy B. & Martynov A. 2018. Morphological diagnoses of higher taxa in Ophiuroidea (Echinodermata) in support of a new classification. European Journal of Taxonomy 416: 1 - 35. https: // doi. org / 10.5852 / ejt. 2018.416","Lyman T. 1878. Ophiuridae and Astrophytidae of the \" Challenger \" expedition. Part I. Bulletin of the Museum of Comparative Zoology 5 (7): 65 - 168.","Stohr S. 2011. New records and new species of Ophiuroidea (Echinodermata) from Lifou, Loyalty Islands, New Caledonia. Zootaxa 50 (1): 1 - 50. https: // doi. org / 10.11646 / zootaxa. 3089.1.1","Koehler R. 1905. Ophiures de l'expedition du Siboga. Part 2. Ophiures littorales. Siboga Expeditie 45 B: 1 - 140.","Koehler R. 1897. Echinodermes recueillis par \" l'Investigator \" dans l'Ocean Indien. I. Les ophiures de mer profonde. Annales des Sciences naturelles Zoologie 8 (4): 277 - 372.","O'Hara T. D. & Stohr S. 2006. Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Richer de Forges B. & Justine J. - L. (ed.) Tropical Deep-Sea Benthos 24: 33 - 141. Museum national d'histoire naturelle, Paris.","O'Hara T. D., Hugall A. F., Thuy B., Stohr S. & Martynov A. V. 2017. Restructuring higher taxonomy using broad-scale phylogenomics: the living Ophiuroidea. Molecular Phylogenetics and Evolution 107: 415 - 430. https: // doi. org / 10.1016 / j. ympev. 2016.12.006","Matsumoto H. 1915. A new classification of the Ophiuroidea: with descriptions of new genera and species. Proceedings of the Academy of Natural Sciences of Philadelphia 67: 43 - 92."]}

Ophioplinthaca plicata (Lyman, 1878) Figs 25–26 Ophiomitra plicata Lyman, 1878: 150, pl. 8 figs 209–212, pl. 9 figs 233–235. Ophioplinthaca vicina Koehler, 1904: 129-130, pl. 25 figs 1–3. Ophiomitra plicata – Lyman 1882: 203–204, pl. 10 figs 7–9. — Li 1987: 143–145, pl. 1 fig. 2. — Liao 2004: 139–140, fig. 70. Ophioplinthaca plicata – O’Hara & Stöhr 2006: 84–85, fig. 8g, m–p. Material examined CHINA • 1 spec.; South China Sea, Zhongsha Islands, seamount; 15°36.20′ N, 113°33.74′ E; depth 1820 m; 27 Sep. 2019; collection event: stn SC014; MSV Shenhaiyongshi leg.; preserved in 95% ethanol; GenBank: MZ 198773, MZ 203269; IDSSE EEB-SW0019. Remarks The present study found only one specimen of O. plicata , with 12.5 mm in disc diameter (Fig. 25). Within Chinese waters, this species has previously been recorded only from the South China Sea. The arm spine articulation is well developed and placed at a slight angle to the distal edge of the lateral arm plate. A volute-shaped perforated lobe is present in most articulations, but is reduced in the dorsalmost one (Fig. 26A–B). The arm spine articulation has a large muscle opening and a small nerve opening (Fig. 26A–B), and it decreases significantly in size ventralwards (Fig. 26A). The vertebrae have a streptospondylous articulation, with a short, broad podial basin at the proximal end and a narrow, small distal end. The dorsal end of the vertebrae is distally triangular and proximally flattened with a longitudinal groove along the midline (Fig. 26C–G). The ventral end of the vertebrae has a broad ambulacral groove without an oral bridge (Fig. 26E). The genus Ophioplinthaca is clearly distinguishable from other genera within the family Ophiacanthidae by the deep interradial incisions into the disc, which are lined distally by enlarged disc scales. Ophioplinthaca plicata is morphologically variable among individuals and is difficult to distinguish from other species of Ophioplinthaca, especially from O. pulchra Koehler, 1904. The morphological features of the specimen of O. plicata from our collection and previous descriptions show complex morphological variation among individuals, and more specimens need to be analyzed from neighboring seas and the Indo-Pacific region to understand their morphological variation with respect to geographic distribution (O’Hara & Stöhr 2006). A molecular analysis using specimens from many localities is required to understand the genetic variation in this species and its impact on morphological variation. Distribution 480–2003 m depth. South China Sea, Philippines, Indonesia, New Caledonia, Kermadec Island, New Zealand, SE Australia (O’Hara & Stöhr 2006; OBIS 2021). Genus Ophiacantha Müller & Troschel, 1842, Published as part of Nethupul, Hasitha, Stöhr, Sabine & Zhang, Haibin, 2022, New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach, pp. 1-95 in European Journal of Taxonomy 810 (1) on page 47, DOI: 10.5852/ejt.2022.810.1723, http://zenodo.org/record/6419522, {"references":["Lyman T. 1878. Ophiuridae and Astrophytidae of the \" Challenger \" expedition. Part I. Bulletin of the Museum of Comparative Zoology 5 (7): 65 - 168.","Koehler R. 1904. Ophiures de l'expedition du Siboga. Part 1. Ophiures de mer profonde. Siboga Expeditie 45 A: 1 - 176.","Lyman T. 1882. Report on the Ophiuroidea. Report of the Scientific Results of the Voyage of H. M. S. Challenger 1873 - 76, Zoology 5 (1): 1 - 386.","Li G. 1987. Deep-sea ophiurans in the South China Sea. Nanhai Studia Marina Sinica 8: 143 - 153.","Liao Y. 2004. Echinodermata: Ophiuroidea. Fauna Sinica: Zoology of China Invertebrates 40. Science Press, Beijing.","O'Hara T. D. & Stohr S. 2006. Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Richer de Forges B. & Justine J. - L. (ed.) Tropical Deep-Sea Benthos 24: 33 - 141. Museum national d'histoire naturelle, Paris.","OBIS 2021. Ocean Biodiversity Information System. Available from www. obis. org [accessed 15 Aug. 2021].","Muller J. & Troschel F. H. 1842. System der Asteriden. 1. Asteriae. 2. Ophiuridae. Vieweg, Braunschweig, Germany."]}

Ophiurothamnus clausa (Lyman, 1878) Figs 23–24 Ophioceramis clausa Lyman, 1878: 124, pl. 6 figs 161–163. Ophiothamnus stultus Koehler, 1904: 141–142, pl. 25 figs 9–10, pl. 26 fig. 1. Ophiurothamnus musorstomae Guille, 1981: 427, fig. 1g –j, pl. 3 figs 20–21. Ophioceramis clausa – Lyman 1882: 26, pl. 11 figs 4–6. Ophiurothamnus stultus – Matsumoto 1917: 130. — Koehler 1922a: 104–105, pl. 22 fig. 1–4. — Liao 2004: 149, fig. 78. Ophiurothamnus clausa – O’Hara & Stöhr 2006: 105, fig. 14 (a–j). — Chen et al. 2020: 651–652, figs 1–2. Material examined CHINA • 1 spec.; South China Sea, SE of Hainan Island, seamount; 17°17.60′ N, 111°34.17′ E; depth 1500 m; 2 Apr. 2018; collection event: stn SC021; MSV Shenhaiyongshi leg.; preserved in 95% ethanol; GenBank: MZ 198777; IDSSE EEB-SW0023 • 2 specs; South China Sea, SE of Hainan Island, seamount; 17°59.21′ N, 111°01.17′ E; depth 1500 m; 1 Apr. 2018; collection event: stn SC020; MSV Shenhaiyongshi leg.; preserved in -80°C; IDSSE EEB-SW0042, IDSSE EEB-SW0043. Remarks The disc diameter (4.5–5.0 mm), the circular disc and the morphology are similar to the description of Ophiurothamnus clausa in O’Hara & Stöhr (2006) and to the description from the South China Sea in Chen et al. (2020), but we identified some variability in the number of scales on the dorsal disc and in the shape of the radial shields (Fig. 23). The arm skeleton characters of O. clausa differ from those of other species in the family Ophiacanthidae. The dorsal arm plate is triangular and well developed (Fig. 24A). The arm spine articulation is well developed and has a large muscle opening and a small nerve opening. A volute-shaped perforated lobe is present in most articulations, but is lacking in the dorsalmost one (Fig. 24B). A perforation is present on the inner side of each lateral arm plate (Fig. 24C). The vertebrae have a long streptospondylous articulation, with broad proximal and distal ends and a narrow middle segment. The proximal end of a vertebra has two clearly separated openings and the distal end of the podial basin becomes short and small. The dorsal side of the vertebrae is distally triangular and proximally flattened, without a keel. The ventral side of the vertebrae has a narrow and straight ambulacral furrow without an oral bridge (Fig. 24D–G). Ophiurothamnus clausa has variable morphological features according to O’Hara & Stöhr (2006), especially regarding the characters of the disc, and the variation in disc covering is very striking, ranging from smooth naked plates to plates with granules, the number and shape of the scales covering the disc, the shape and position of the radial shields and the shape of the arm spines. These character differences cannot be explained by biogeographic distribution or size of the animal (O’Hara & Stöhr 2006) and may instead be evidence of cryptic speciation. Distribution 480–3202 m depth. East China Sea, South China Sea, Indonesia, Australia, New Zealand, Kermadec Islands, Philippines, New Caledonia, Papua New Guinea, Mozambique Channel (O’Hara & Stöhr 2006; OBIS 2021). Genus Ophioplinthaca Verrill, 1899, Published as part of Nethupul, Hasitha, Stöhr, Sabine & Zhang, Haibin, 2022, New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach, pp. 1-95 in European Journal of Taxonomy 810 (1) on pages 44-47, DOI: 10.5852/ejt.2022.810.1723, http://zenodo.org/record/6419522, {"references":["Lyman T. 1878. Ophiuridae and Astrophytidae of the \" Challenger \" expedition. Part I. Bulletin of the Museum of Comparative Zoology 5 (7): 65 - 168.","Koehler R. 1904. Ophiures de l'expedition du Siboga. Part 1. Ophiures de mer profonde. Siboga Expeditie 45 A: 1 - 176.","Guille A. 1981. Echinodermes: Ophiurides. In: Forest J. (ed.) Resultats des Campagnes MUSORSTOM: 1. Philippines. Memoires ORSTOM 91: 413 - 456. Museum national d'histoire naturelle, Paris.","Lyman T. 1882. Report on the Ophiuroidea. Report of the Scientific Results of the Voyage of H. M. S. Challenger 1873 - 76, Zoology 5 (1): 1 - 386.","Matsumoto H. 1917. A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College of Science, Imperial University, Tokyo 38: 1 - 408.","Koehler R. 1922 a. Ophiurans of the Philippine seas and adjacent waters. United States National Museum Bulletin 5 (100): 1 - 480.","Liao Y. 2004. Echinodermata: Ophiuroidea. Fauna Sinica: Zoology of China Invertebrates 40. Science Press, Beijing.","O'Hara T. D. & Stohr S. 2006. Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. In: Richer de Forges B. & Justine J. - L. (ed.) Tropical Deep-Sea Benthos 24: 33 - 141. Museum national d'histoire naturelle, Paris.","Chen W. Y., Zhang D. & Wang C. 2020. Two new records of genus Ophiurothamnus (Ophiuroidea, Ophiacanthidae) from a deep-sea seamount of the South China Sea. Oceanologia et Limnologia Sinica 51 (3): 649 - 655. https: // doi. org / 10.11693 / hyhz 20191100232","OBIS 2021. Ocean Biodiversity Information System. Available from www. obis. org [accessed 15 Aug. 2021]."]}

Ophiacantha bathybia H.L. Clark, 1911 Figs 27–28 Ophiacantha bathybia H.L. Clark, 1911: 233–234. Material examined CHINA • 1 spec.; South China Sea, E of Hainan Island, seamount; 18°11.96′ N, 114°21.01′ E; depth 3536 m; 11 Sep. 2017; collection event: stn SC016; MSV Shenhaiyongshi leg.; GenBank: MZ 203273; IDSSE EEB-SW0024 • 1spec.; South China Sea,E of Hainan Island, seamount; 18°11.93′N, 114°21.01′ E; depth 1550 m; 9 Sep. 2017; collection event: stn SC016; MSV Shenhaiyongshi leg.; GenBank: MZ 203274; IDSSE EEB-SW0025 • 1 spec.; South China Sea, E of Hainan Island; 18°12.03′ N, 114°21.25′ E; depth 3500 m; 6 Sep. 2017; collection event: stn SC016; MSV Shenhaiyongshi leg.; preserved in -80°C; IDSSE EEB-SW 0044. Description (IDSSE EEB-SW 0025) MEASUREMENTS. Disc diameter 17.5 mm. DiSC. Flat, pentagonal, covered by thin skin, underlying scales with short disc spines (Fig. 27A–B), 0.3–0.4 mm high, rough, with two to three sharp terminal thorns, similar on both dorsal and ventral disc (Fig. 27C–E). Radial shields long, narrow, well separated, parallel to each other, concealed by thin skin, their form and position clearly visible through skin, with thorny stumps (Fig. 27A, E). Ventral disc near oral shields with scales without thorny stumps (Fig. 27B). Oral shield much wider than long, broadly triangular, with wide, pointed proximal angle and a straight or convex distal edge (Fig. 27F). Madreporite larger, with central depression, pentagonal. Adoral shields large, three times as long as wide, narrow, not separated (Fig. 27B, F). Adoral shields enclose proximal oral shield edges and extend around it, separating it from first lateral arm plate (Fig. 27C, F). Jaws wider than long, ventralmost tooth with large, blunt, pointed or flat edge, and three pointed, spiniform lateral oral papillae with thick and rounded base (Fig. 27F). Genital slits conspicuous and extending from oral shield to periphery of disc (Fig. 27I). ARMS. Dorsal arm plate on first few arm segments triangular, somewhat fan-shaped and distal margin more convex, but along arm becoming straighter, towards rhombic, somewhat swollen, two times as wide as long, barely separated (Fig. 27G). Ventral arm plate widely triangular, two times as wide as long, distal margin convex, proximally with low, wide angle, lateral side weakly concave and widely separated, but along arm ventral arm plate decreasing in size, as wide as long, with convex distal margin (Fig. 27H). Lateral arm plates meeting above and below, but along arm becoming separated ventrally (Fig. 27H). Six sharp and thorny arm spines (Fig. 27J). Three uppermost spines longest, two to three arm segments in length, one to two dorsal arm spines smooth but others thorny (Fig. 27K). Two to three tapering ventral arm spines with rough tip (Fig. 24L). One tentacle scale, elongated, half as long as ventral arm plate, pointed (Fig. 27I). COLOR. When alive, entire specimen light red, light brown when dry (Fig. 27A–B). OSSiCLE MORPHOLOGY. Arm spine articulation well developed and placed at small angle to distal edge of lateral arm plate (Fig. 28A–B). Volute-shaped perforated lobe forms most articulations, but reduced in dorsalmost articulation (Fig. 28A–B). Arm spine articulation with large muscle opening (Fig. 28B). Ventral arm spine smooth, but with rough tip (Fig. 28C). Vertebrae with a well-developed zygospondylous articulation, with a broad dorsal surface, distally abruptly truncated, with a shallow dorsal medial furrow, podial basins slightly wider than long (Fig. 28D–H). Ambulacral groove widened in middle, without oral bridge (Fig. 28G). Remarks Ophiacantha bathybia was described by H.L. Clark (1911); additional specimens have been collected in 1980, 1981 and 2015 (OBIS 2021). Ophiacantha bathybia from the present study is quite similar to the holotype description, but it differs in the arm spine and arm plate characters. Our specimens were larger than the holotype (12 mm disc diameter) and some of the morphological differences may be caused by this size difference. The lateral arm plates in the holotype description are connected at both the dorsal and ventral edges, but in our specimens they were only connected by a ligament. Another morphological variation was the number of thorny spines, which differs from segment to segment and arm to arm. Ophiacantha bathybia has no uniquely distinguishing characters, but appears to be different from other species of Ophiacantha by the size of the disc and characters of the disc covering, dorsal arm plates, arm spines and tentacle scale. Mature specimens have narrow, long radial shields and thorny disc stumps, but differ in arm spine and dorsal arm plate shape. It has been recorded from abyssal depths, and its morphological characters are similar to those of other abyssal species of Ophiacantha, namely O. pacifica Lütken & Mortensen, 1899, O. sollicita Koehler, 1922, O. cosmica Lyman, 1878, O. frigida Koehler, 1907 and O. sociabilis Koehler, 1897, but these species have been recorded from Panama, the Southern Ocean and the Atlantic Ocean. Ophiacantha bathybia may be considered as a sister species to these abyssal species of Ophiacantha based on their morphological features. Ophiacantha cosmica differs from O. bathybia by having up to eight arm spines, slender lateral oral papillae without a thick base and a blunt ventralmost tooth (Lütken & Mortensen 1889; Stöhr & O’Hara 2021). Ophiacantha sociabilis differs from O. bathybia by having four to five lateral oral papillae, a less enlarged distalmost papilla and wider jaws (Koehler 1897; Stöhr & O’Hara 2021). Ophiacantha sollicita differs from O. bathybia by having up to eight arm spines, conical disc spines, a notably thickened distal oral papilla and non-moniliform arms (Koehler 1922b). Ophiacantha frigida differs from O. bathybia by having a larger distalmost lateral oral papilla and usually two tentacle scales on the first tentacle pore (Koehler 1922b). Ophiacantha pacifica is highly similar to O. bathybia in morphological features of the oral frame, as well as the number and length of arm spines, but the ventralmost arm spines of O. bathybia have a rough tip (Lütken & Mortensen 1889) (Fig. 28C). However, these morphological differences vary and overlap among individuals between species of the genus Ophiacantha. Therefore, a molecular analysis from a wider range of localities is needed to understand the species boundaries. Distribution 1602–3656 m depth. South China Sea, Alaska, British Colombia, Bering Sea, Shumagin Island, Makassar Strait and Northwest Pacific (OBIS 2021)., Published as part of Nethupul, Hasitha, Stöhr, Sabine & Zhang, Haibin, 2022, New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach, pp. 1-95 in European Journal of Taxonomy 810 (1) on pages 47-53, DOI: 10.5852/ejt.2022.810.1723, http://zenodo.org/record/6419522, {"references":["Clark H. L. 1911. North Pacific ophiurans in the collection of the United States National Museum. United States National Museum Bulletin 75: 1 - 302.","Lyman T. 1878. Ophiuridae and Astrophytidae of the \" Challenger \" expedition. Part I. Bulletin of the Museum of Comparative Zoology 5 (7): 65 - 168.","OBIS 2021. Ocean Biodiversity Information System. Available from www. obis. org [accessed 15 Aug. 2021].","Koehler R. 1907. Note preliminaire sur quelques asteries et ophiures provenant des campagnes de la Princesse Alice. Bulletin de l'Institut oceanographique 99: 1 - 47.","Koehler R. 1897. Echinodermes recueillis par \" l'Investigator \" dans l'Ocean Indien. I. Les ophiures de mer profonde. Annales des Sciences naturelles Zoologie 8 (4): 277 - 372.","Lutken C. F. & Mortensen T. 1889. Reports on an exploration off the west coasts of Mexico, Central and Southern America and off the Galapagos Islands. XXV. The Ophiuridae. Memoirs of the Museum of Comparative Zoology 23 (2): 97 - 208.","Koehler R. 1922 b. Echinodermata: Ophiuroidea. Australasian Antarctic Expedition 1911 - 1914, Scientific Report Series C 8 (2): 5 - 98."]}

Ophiacantha vorax Koehler, 1897 Figs 29–30 Ophiacantha vorax Koehler, 1897: 353–356, pl. 8 figs 68–69. Ophiacantha anchilabra H.L. Clark, 1911: 204–206, fig. 95. Ophiacantha vorax – Koehler 1899: 62, pl. 7 figs 52–54; 1922a: 63, pl. 15 figs 4–5. — Liao 2004: 122–123, fig. 59. Ophiacantha anchilabra – H.L. Clark 1915: 196. — Matsumoto 1917: 117. Material examined CHINA • 1 spec.; South China Sea, SE of Hainan Island, seamount; 17°59.21′ N, 111°01.17′ E; depth 1500 m; 1 Apr. 2018; collection event: stn SC020; MSV Shenhaiyongshi leg.; preserved in -95°C ethanol; GenBank: MZ 198765, MZ 203267; IDSSE EEB-SW0011 • 1 spec.; South China Sea, SE of Hainan Island, sea plain; 18°26.13′ N, 111°49.09′ E; depth 1576 m; 26 Jun. 2019; collection event: stn SC001; MSV Shenhaiyongshi leg.; preserved in -80°C; GenBank: MZ 198766, MZ 203268; IDSSE EEB-SW0012 • 1 spec.; South China Sea, SE of Hainan Island, seamount; 17°17.60′ N, 110°34.18′ E; depth 1500 m; 2 Apr. 2018; collection event: stn SC021; MSV Shenhaiyongshi leg.; preserved in -80°C; IDSSE EEB-SW0045. Description (IDSSE EEB-SW 0011) MESUREMENTS. Disc diameter 6.2 mm. DiSC. Sub-pentagonal, covered by skin with underlying scales, bearing four to six short, stump-like spines with crown of sharp, straight thorns and a few elongated thick, thorny stumps in the center (Fig. 29A–F). Radial shields long, narrow, widely separated, slightly convex, distal end thickened and exposed (Fig. 29A). Radial shields concealed by thin skin and thorny stumps, but clearly visible through skin when specimen dried (Fig. 29A). Dorsal arm plate on first arm segment covered by thorny stumps (Fig. 29D). Ventral disc also covered by thorny stumps, but less dense than on dorsal disc, scales clearly visible, genital slits short (Fig. 29F). Oral shield triangular, much wider than long, distal end slightly convex, proximal edges concave or straight (Fig. 29B), madreporite larger, as long as wide, distal edge strongly convex (Fig. 29G). Adoral shields narrow, curved, three times as long as wide and not separated, bordering proximal edges of oral shield, not separating it from arm (Fig. 29G). Jaws elongated, with one large pointed ventralmost tooth and three long, spiniform, pointed lateral oral papillae on each side, distalmost papilla wider than other two (Fig. 29G). ARMS. Dorsal arm plates triangular, distal edge convex, separated (Fig. 29I). Ventral arm plate on first arm segment small, wider than long, slightly triangular with concave distal edge. Second ventral arm plate pentagonal, wider than long, with obtuse proximal angle, excavated lateral edges and slightly convex distal edge. Following plates as wide as long, distalwards becoming wider than long, slightly hexagonal, with curved distal edge and angular proximal edges, separated except on second arm segment (Fig. 29H, J). Lateral arm plates meeting above and below. Six smooth arm spines, three dorsal and three ventral. Dorsalmost arm spine one and a half to two arm segments in length, second dorsalmost arm spine longest and meeting across dorsal midline (Fig. 29I–J). Ventral arm spines similar in length, with finely thorny surface (Fig. 29K). One elongated tentacle scale, large, often as long as ventral arm plate (Fig. 29H). COLOR. When alive, entire specimen light brown, darker brown when dry (Fig. 29). OSSiCLE MORPHOLOGY.Arm spine articulations well-developed, placed at an angle on separate, protruding distal part of lateral plate, bordered by a wavy ridge, middle articulations largest (Fig. 30A–B). Arm spine with thorny surface (Fig. 30C). Volute-shaped perforated lobe in most articulations, reduced in dorsalmost articulation, with large muscle opening and small nerve opening (Fig. 30A–B). Vertebrae with short, well-developed zygospondylous articulation with a broad, shallow dorsal furrow, distally abruptly truncated, podial basins wider than long (Fig. 30D–H). Ambulacral groove widely diverging distally, without oral bridge (Fig. 30H). Remarks The holotype description of the dorsal disc of Ophiacantha vorax (5 mm disc diameter) is slightly different from conditions in our specimen, which has no elongated disc stumps. However, this morphological feature was only found here on one of the 3 specimens collected. Variability in morphological characters (arm spines, extent of thorny stumps on radial shields, tentacle scale) is low in O. vorax (Koehler 1922a). Koehler (1897) considered one of the distinguishing features of O. vorax to be the presence of only six arm spines, but H.L. Clark (1911) and Liao (2004) documented eight to nine arm spines in their specimens. Therefore, the number of arm spines is not a suitable character to distinguish O. vorax from other species of Ophiacantha. Ophiacantha pentagona Koehler, 1897 is related to O. vorax, but differs in having long and thicker oral papillae, strongly moniliform arms and longer ventral arm plates in the middle region of the arm. Ophiacantha vorax closely resembles O. longidens Lyman, 1878 in the shape of the oral papillae and oral shields, as well as in the disc shape, but differs in the arrangement of arm spines, and the shape of the arm plates and tentacle scales. Ophiacantha longidens has flattened arm spines, blunt with a thorny surface. Another species resembling O. vorax is O. duplex Koehler, 1897, recorded from deep waters in Japan, Philippines, Indonesia, Australia and Madagascar. It can clearly be distinguished by its large tentacle scale, less thorny, long, thin arm spines, large dorsal arm plate and the presence of large disc spines, as well as the smaller thorned spines. Distribution 550–1908 m depth. South China Sea, East China Sea, off East Japan, India, Philippines, Indonesia, Makassar Strait and Molucca Sea, Coral Sea and New Zealand (OBIS 2021)., Published as part of Nethupul, Hasitha, Stöhr, Sabine & Zhang, Haibin, 2022, New species, redescriptions and new records of deep-sea brittle stars (Echinodermata: Ophiuroidea) from the South China Sea, an integrated morphological and molecular approach, pp. 1-95 in European Journal of Taxonomy 810 (1) on pages 53-57, DOI: 10.5852/ejt.2022.810.1723, http://zenodo.org/record/6419522, {"references":["Koehler R. 1897. Echinodermes recueillis par \" l'Investigator \" dans l'Ocean Indien. I. Les ophiures de mer profonde. Annales des Sciences naturelles Zoologie 8 (4): 277 - 372.","Clark H. L. 1911. North Pacific ophiurans in the collection of the United States National Museum. United States National Museum Bulletin 75: 1 - 302.","Koehler R. 1899. An Account of the Deep-Sea Ophiuroidea Collected by the Royal Indian Marine Survey. Trustees of the Indian Museum, Calcutta.","Liao Y. 2004. Echinodermata: Ophiuroidea. Fauna Sinica: Zoology of China Invertebrates 40. Science Press, Beijing.","Clark H. L. 1915. Catalogue of recent ophiurans, based on the collection of the Museum of Comparative Zoology. Memoirs of the Museum of Comparative Zoology at Harvard College 25 (4): 164 - 376.","Matsumoto H. 1917. A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College of Science, Imperial University, Tokyo 38: 1 - 408.","Koehler R. 1922 a. Ophiurans of the Philippine seas and adjacent waters. United States National Museum Bulletin 5 (100): 1 - 480.","Lyman T. 1878. Ophiuridae and Astrophytidae of the \" Challenger \" expedition. Part I. Bulletin of the Museum of Comparative Zoology 5 (7): 65 - 168.","OBIS 2021. Ocean Biodiversity Information System. Available from www. obis. org [accessed 15 Aug. 2021]."]}

Ophiacantha aster sp. nov. urn:lsid:zoobank.org:act: 6AB8A891-700D-4BF2-8873-5CD18178795E Figs 31–33 Diagnosis Disc slightly pentagonal, interradially excavated and covered by conical pointed granules with wide, round base. Single small, broad, triangular, pointed tentacle scale. Adoral shields larger than oral shield. Jaw with one large, blunt, wide ventralmost tooth and four to five lateral oral papillae. Top of radial shields and center of disc creamy white, dark brown lines radiate from disc center to arms. Etymology The specific name is derived from the Greek word for ‘star’, alluding to the shape and color of the dorsal disc. Material examined Holotype CHINA • South China Sea, SE of Zhongsha Islands, seamount; 13°59.70′ N, 115°24.81′ E; depth 516 m; 20 Sep. 2020; collection event: stn SC011; MSV Shenhaiyongshi leg.; preserved in 95% ethanol; GenBank: MZ 203275; IDSSE EEB-SW0026. Paratypes CHINA • 1 spec.; same collection data as for holotype; GenBank: MZ 203276; IDSSE EEB-SW0027 • 12 specs; same collection data as for holotype; IDSSE EEB-SW0046 to EEB-SW0057. Description (holotype) MEASUREMENTS. Disc diameter 8.5 mm. DiSC. Disc slightly pentagonal, interradially excavated, covered by oval disc scales, each bearing a conical pointed granule with wide, round base (Fig. 31A–B). At disc periphery and lateral disc, granules lower and less pointed, near oral shields no granules on scales (Fig. 31C–F). In disc center, granules spine-like (Fig. 31C). Ventral disc reduced to oral frame (Fig. 31B). Radial shields long, narrow, parallel to each other, but well separated, distal ends exposed (Fig. 31A, E). Genital slits conspicuous, short, extending from oral shield to periphery of disc (Fig. 31E). Oral shield broadly triangular, with acute proximal angle, with straight, convex or wavy distal edge. Adoral shields larger than oral shield, trapezoid extending along concave proximal edges of oral shield, not separating it from arm (Fig. 31F). Jaw with one large, blunt, wide ventralmost tooth, four to five lateral oral papillae, first three elongated, spiniform, first possibly infradental papilla, distal two papillae larger, distalmost one scale-like (possibly adoral shield spine) (Fig. 31F). Dorsal teeth square, with straight proximal edge (Fig. 31F). ARMS. Moniliform. Dorsal arm plates fan-shaped, distal edge convex, acute proximal angle, straight to slightly concave proximolateral edges, completely separated (Fig. 31G). Ventral arm plates pentagonal to broadly rectangular, wider than long, concave lateral edges around tentacle pore, distal edge straight with small inward curve, separated (Fig. 31H). Lateral arm plates with a high spine-bearing ridge, meeting dorsally and ventrally (Fig. 31I–K). Eight transparent, rounded arm spines, more or less thorny (Fig. 31J–K). Four dorsalmost spines longest, with rough surface, as long as three arm segments, meeting at dorsal midline, length gradually decreasing ventralwards. Ventral arm spines tapering, rougher than dorsal arm spines, one to two arm segments in length (Fig. 31I–K). Tentacle pore on proximalmost and second arm segments half to two-thirds arm segment in length (Fig. 31B). One to three arm segments covered by disc and only possessing ventral arm spines (Fig. 31I). Arm spines on fourth to sixth arm segments longer than those on middle or dorsal arm segments (Fig. 31I–J). Arm spines on first six arm segments tapered, smooth, but distal to sixth segment spines rough or thorny (Fig. 31K). One small, broad, triangular, pointed tentacle scale, one third as long as ventral arm plate (Fig. 31B). COLOR. Top of radial shields and center of disc creamy white, but dark brown lines radiate from disc center to arms, outside radial shields, a third line between each pair of radial shields continues along center of each arm. Similar longitudinal, lighter brown line on ventral arms (Fig. 31). OSSiCLE MORPHOLOGY. Proximal lateral arm plate short, strongly curved and arm spine articulations well developed, with large muscle opening and small nerve opening (Fig. 32A). Spine articulations volute-shaped perforated lobe (Fig. 32A–B). Arm spines with sparse thorns (Fig. 32C). Vertebrae with a short streptospondylous articulation, as wide as long, proximal end with podial basins. Dorsal end of vertebrae distally triangular, proximally slightly curved inwards, with shallow dorsal furrow (Fig. 32D–H). Ambulacral groove without oral bridge (Fig. 32F–G). Variations in paratypes Paratypes generally similar to holotype, disc diameters 3.9–9.0 mm, but some morphological variations were observed. Only dorsal arm spines tapered or thorny in some specimens (Fig. 33). One paratype had black dots scattered near periphery of disc (Fig. 33A). Disc color of some paratypes slightly lighter than in holotype and interradials not as strongly excavated as in holotype, radial shields more widely separated (Fig. 33B). Smallest paratype with 3.9 mm disc diameter and similar to holotype, except fifth arm segments with thorny spines. Lateral oral papillae four to six, distalmost one varies from scalelike, flat to narrower and pointed, ventralmost tooth much larger than oral papillae (Fig. 33C–D). Disc granules varied in shape; some specimens with taller spines in disc center (Fig. 33E). Remarks The arm spine articulation is here interpreted as a variation of the zygospondylous type, not uncommon in the family Ophiacanthidae, typical of epizoic species. The deeply interradially excavated disc is a character used by Paterson (1985) to distinguish the no longer valid subfamily Ophioplinthacinae Paterson, 1985 (Martynov 2010), but the narrow, long radial shields and the oral frame fit with the genus Ophiacantha. Ophiacantha aster sp. nov. differs from most species of the genus by having deep incisions in the disc along with five (more or less) lateral oral papillae. Ophiacantha antarctica Koehler, 1900 resembles O. aster sp. nov. by having long narrow radial shields with a more or less excavated interradial disc, four elongated lateral oral papillae and tapering long uppermost arm spines, but it differs in having a thickened integument that covers the disc scales, conical granules on the scales with two to five fine spinules, and near the periphery of the disc the granules are less elongated and more cylindrical. Ophiacantha antarctica has seven arm spines with a thin pointed tip (Koehler 1900), frequently has disc spines on the dorsal arm plates and transversely split dorsal arm plates dividing them into a small proximal and larger distal section (observation from anonymous reviewer). Another species that resembles Ophiacantha aster sp. nov. is O. veterna Koehler, 1907, known from the Atlantic Ocean (2200 m), which has similar morphological characteristics in its disc shape, oral shield, adoral shield, oral papillae and arm spines, but differs mainly in having dense small granules on both ventral and dorsal disc and in the shape of the ventral arm plate along the arm (Koehler 1907 a). The new species is unusually colorful among deep-water species. Distribution and habitat Found on a seamount near the Zhongsha Islands, South China Sea (516 m) as a colony attached to a dead coral branch. The vertebrae of Ophiacantha aster sp. nov. are almost streptospondylous and suggest an epizoic life-style, typical of suspension feeders. Genus Ophiomoeris Koehler, 1904

Ophiosabine cuspidata (Lyman 1878b) comb. nov. Fig. 6C–E Ophiacantha cuspidata Lyman, 1878b: 143, pl. 10(248–250).— Lyman 1882: 191–192, pl. 15(9–10), 41(12–14).— Mortensen 1933c: 31–33, fig. 17–18(a–c), pl. 3(3–4).— Martynov & Litvinova 2008: fig. 7d. Material examined. MD 50 DC49, MNHN IE.2009.1558 (1). MD 50 DC91, MNHN IE.2009.1559 (1). MD 50 CP152, MNHN IE.2009.1560 (2). MD 50 CP178, MNHN IE.2009.1561 (1). Distribution. Arctic (781–1505 m), NE Atlantic (1315–2669 m), W Atlantic (274– 274 m), E Atlantic (781– 1236 m). SPA (880–1275 m). Remarks. The new specimens are very similar to the types of O. cuspidata found off Ascension Is (781 m) on the Mid-Atlantic Ridge (see Martynov & Litvinova 2008, fig. 7D). They have relatively sparse but long elongate disc spines with thorns diverging at the tip, radial shields marked by a furrow and small exposed distal section, four oral papillae, the outmost widened (sometimes with a groove), pentagonal oral shields, with obtuse proximal margins and a large squarish distal lobe, 8–9 arm spines, and a pointed tentacle scale (Fig. 6C–E). The MD 50 specimens measure 6–10.5 mm dd, compared with 9 mm for the holotype (Lyman 1882). The MD 50 specimens also have small thorns on the distal edge of the dorsal arm plates that were not recorded for the O. cuspidata types but may have been overlooked. Martynov and Litvinova (2008) synonymised the five-armed O. cuspidata with the six-armed O. anomala. They are very similar, and mitochondrial sequence data indicates that for other Ophiosabine species, such as O. pentactis, five and six-armed specimens can be in the same clade (O’Hara et al. 2013). However, in this instance, the holotype of O. cuspidata from Ascension Island in the South Atlantic appears to be distinct from other five-armed specimens from the North Atlantic that are close to O. anomala (see Martynov & Litvinova 2008, fig. 7C). The disc spines on the five- and six-armed O. anomala are shorter and stouter (see Martynov & Litvinova 2008, fig. 7H–I; Mortensen 1933c, fig. 18c) than shown for O. cuspidata, and here we recognise the latter as a distinct species., Published as part of O'Hara, Timothy D. & Thuy, Ben, 2022, Biogeography and taxonomy of Ophiuroidea (Echinodermata) from the Îles Saint- Paul and Amsterdam in the southern Indian Ocean, pp. 1-49 in Zootaxa 5124 (1) on page 18, DOI: 10.11646/zootaxa.5124.1.1, http://zenodo.org/record/6404674, {"references":["Lyman, T. (1878 b) Ophiuridae and Astrophytidae of the exploring voyage of H. M. S. Challenger, under Prof. Sir Wyville Thomson, F. R. S. Part 1. Bulletin of the Museum of Comparative Zoology, Harvard University, 5, 65 - 168, 10 pls.","Lyman, T. (1882) Ophiuroidea. Report on the Scientific Results of the Voyage of the \" Challenger \" Zoology, 5, 1 - 385 pls. 1 - 48.","Mortensen, T. (1933 c) Ophiuroidea. The Danish Ingolf Expedition, 4, 1 - 120, 3 pls.","Martynov, A. V. & Litvinova, N. M. (2008) Deep-water Ophiuroidea of the northern Atlantic with descriptions of three new species and taxonomic remarks on certain genera and species. Marine Biology Research, 4, 76 - 111. https: // doi. org / 10.1080 / 17451000701840066","O'Hara, T. D., Smith, P. J., Mills, V. S., Smirnov, A. V. & Steinke, D. (2013) Biogeographical and phylogeographical relationships of the bathyal ophiuroid fauna of the Macquarie Ridge, Southern Ocean. Polar Biology, 36, 321 - 333. https: // doi. org / 10.1007 / s 00300 - 012 - 1261 - 9"]}

Genus Ophiosabine gen. nov. http://zoobank.org/ urn:lsid:zoobank.org:act: 19CBDBB0-7DF5-46C7-9C62-592BD6EC0A80 Diagnosis. Disc covered in thin scales and armoured with stout thorny spines, smooth spines or granules; radial shields mostly obscured, only evident by a shallow furrow and small exposed distal section on the disc; oral shields 1–3 times longer than wide, pentagonal to square, with an obtuse proximal angle or straight proximal margin and rounded to square distal margin; adoral shields small, usually situated proximal to the oral shields; 3–5 spiniform oral papillae, the outer one usually widened, suboral papillae can be present around the second oral tentacle pore; DAPs triangular to fan-shaped, separate, sometimes edged with small thorns; VAPs with an obtuse angle proximally, and an uplifted rounded distal edge, can be glassy and striated; 6–10 long hollow cylindrical arm spines, rounded at tip, finely denticulate; tentacle pores small, one large oval to pointed tentacle scale on most pores, sometimes two on first arm segment. Included species. Ophiacantha rosea Lyman, 1878b (type species); Ophiacantha anomala Sars, 1872; Ophiacantha aristata Koehler, 1896b; Ophiacantha cuspidata Lyman, 1878b; Ophiacantha densispina Mortensen, 1936; Ophiacantha nodosa Lyman, 1878b; Ophiacantha notata Koehler, 1906; Ophiacantha parcita Koehler, 1906; Ophiacantha pentactis Mortensen, 1936; Ophiacantha vivipara Ljungman, 1871; Ophiacantha wolfarntzi Martín-Ledo et al., 2013. Remarks. The molecular phylogenies presented in O’Hara et al. (2017) and Christodoulou et al. (2019) show that the genus Ophiacantha Müller & Troschel, 1842, is polyphyletic, with some species even occurring in the Ophiotomidae (see O. spectabilis below). Amongst the many nominal Ophiacantha species that are not closely related to the type species O. bidentata (Bruzelius 1805), there is a monophyletic clade with a coherent morphology that contains the species O. rosea and O. vivipara that is here named as a new genus Ophiosabine. The most prominent feature is the unusual oral shield that usually is longer than wide and can be almost rectangular in some species (e.g., O. rosea) and the small interradially-contiguous adoral shields that are placed proximal to the oral shields. There is DNA evidence that, as well as O. rosea and O. vivipara, this genus includes the Southern Ocean O. pentactis, O. densispina and O. wolfarntzi, as well as the Atlantic species O. anomala, O. cuspidata, O. aristata (Christodoulou et al. 2019; Martín-Ledo et al. 2013; O’Hara et al. 2013). In addition, the Atlantic species O. nodosa, O. notata and O. parcita share many morphological features of the group. Several taxonomists have noted the similarity of the six-armed O. nodosa and O. anomala (Mortensen 1933c; Paterson 1985). However, Paterson (1985) found morphological characters that distinguished the two species and the two species differ in depth distribution, with the holotype and only known specimen of O. nodosa collected from much lower depths (2789 m) than is characteristic for O. anomala (141–1200 m). As well as the typical oral shield, O. notata and O. parcita share the glassy striated nature of the VAPs that occur in O. wolfarntzi. Several other little-known species are also similar but have been described or figured with certain morphological features that make their assignment to Ophiosabine uncertain. The Atlantic species O. lineata Koehler, 1896a and O. metallacta H.L. Clark, 1915 have disc spines in the form of short cylindrical stumps with a rim of thorns. Ophiomitrella porrecta Koehler, 1914 from the Straits of Magellan (636 m) has a very elongated jaw, Ophiacantha atopostoma H.L. Clark, 1911 from the Bering Sea (629–681 m) has round exposed patches on the radial shields, and O. acanthinotata H.L. Clark, 1911 from Japan (309–331 m) has oral shields that “tend to become triangular”. All these species require further critical examination. There are also numerous cryptic species in this group which complicate the nomenclature. Ophiosabine vivpara consists of three clades in the Southern Ocean (Brogger & O’Hara 2015; O’Hara et al. 2013). Ophiosabine rosea consists of numerous clades around Australia / New Zealand and New Caledonia (Christodoulou et al. 2019; O’Hara et al. 2013), which may not be the same species as the type collected from off Chile. COI sequences of O. densispina from South Georgia (Martín-Ledo et al. 2013) are distinct from those around southern Australia (O’Hara et al. 2013). There is a second unnamed species at South Georgia closely related to O. wolfarntzi (Martin-Ledo, 2013). The micromorphology of ophiuroid lateral arm plates has been shown to yield a wealth of characters potentially relevant for taxon diagnoses and phylogenetic analyses (Martynov 2010; Thuy & Stöhr 2011, 2016). A recent study suggested that lateral arm plate morphologies among species of the Ophiacanthidae are consistent with clades resolved by molecular evidence (Numberger-Thuy & Thuy 2020; O’Hara et al. 2017). Although the number of species analysed by Numberger-Thuy and Thuy (2020) only reflects a small part of the ophiacanthid spectrum, the study suggests that the lateral arm plates of Ophiosabine rosea have a uniquely shaped vertebral articular structure on their inner side. In order to corroborate this preliminary observation and potentially establish the shape of the vertebral articular structure as a diagnosing character of the genus Ophiosabine, more species will have to be examined with respect to their lateral arm plate morphology. There is no available genus-level name for the group. Verrill (1899b) created the subgenus Ophientodia for O. cuspidata, Ophiacantha scutata Lyman, 1878a and O. pectinula Verrill, 1899a (= echinulata Lyman, 1878a) but didn’t designate a type species. However, as he only reported examining specimens of O. scutata and echinulata it seems improbable that he would have intended O. cuspidata to be the type species. Likewise, he created the subgenus Ophiectodia Verrill, 1899b, without designating a type species, which contained O. enopla Verrill, 1885, O. rosea and O. spectabilis but only listed material he had examined of O. enopla. Both of Verrill’s proposed subgenera would now be regarded as polyphyletic assemblages. Etymology. Named using the typical “Ophio” prefix of brittle star genera and after our colleague, ophiuroid taxonomist and friend Sabine Stöhr of the Swedish Museum of Natural History. Gender is feminine., Published as part of O'Hara, Timothy D. & Thuy, Ben, 2022, Biogeography and taxonomy of Ophiuroidea (Echinodermata) from the Îles Saint- Paul and Amsterdam in the southern Indian Ocean, pp. 1-49 in Zootaxa 5124 (1) on pages 17-18, DOI: 10.11646/zootaxa.5124.1.1, http://zenodo.org/record/6404674, {"references":["Lyman, T. (1878 b) Ophiuridae and Astrophytidae of the exploring voyage of H. M. S. Challenger, under Prof. Sir Wyville Thomson, F. R. S. Part 1. Bulletin of the Museum of Comparative Zoology, Harvard University, 5, 65 - 168, 10 pls.","Sars, G. O. (1872) Nye Echinodermer fra den norske kyst. Videnskabelige Selskabets Forhandlinger, 1871, 1 - 31.","Koehler, R. (1896 b) Resultats scientifiques de la compagne du Caudan dans de Golfe de Gascogne. Echinodermes. Annales de l'Universite de Lyon, 26, 33 - 122. https: // doi. org / 10.5962 / bhl. title. 65730","Mortensen, T. (1936) Echinoidea and Ophiuroidea. Discovery Reports, 12, 199 - 348, 9 pls. https: // doi. org / 10.5962 / bhl. part. 8051","Koehler, R. (1906) Description des ophiures nouvelles recueillies par le Travailleur et le Talisman. Memoires de la Societe Zoologique de France, 19, 5 - 34 pls. 1 - 3.","Martin-Ledo, R., Sands, C. J. & Lopez-Gonzalez, P. J. (2013) A new brooding species of brittle star (Echinodermata: Ophiuroidea) from Antarctic waters Polar Biology, 36, 115 - 126. https: // doi. org / 10.1007 / s 00300 - 012 - 1242 - z","O'Hara, T. D., Hugall, A. F., Thuy, B., Stohr, S. & Martynov, A. V. (2017) Restructuring higher taxonomy using broad-scale phylogenomics: the living Ophiuroidea. Molecular Phylogenetics and Evolution, 107, 415 - 430. https: // doi. org / 10.1016 / j. ympev. 2016.12.006","Christodoulou, M., O'Hara, T. D., Hugall, A. F. & Arbizu, P. M. (2019) Dark Ophiuroid Biodiversity in a Prospective Abyssal Mine Field. Current Biology, 29 (e 3), 3909 - 3912.","Muller, J. & Troschel, F. H. (1842) System der Asteriden. Braunschweig: Papier, Druck und Verlag.","Bruzelius, N. (1805) Dissertatio sistens species cognitas asteriarum, quamr. sub praesidio A. J. Retzii. exhibet N. Bruzelius. s. n., Lundae, 37 pp.","O'Hara, T. D., Smith, P. J., Mills, V. S., Smirnov, A. V. & Steinke, D. (2013) Biogeographical and phylogeographical relationships of the bathyal ophiuroid fauna of the Macquarie Ridge, Southern Ocean. Polar Biology, 36, 321 - 333. https: // doi. org / 10.1007 / s 00300 - 012 - 1261 - 9","Mortensen, T. (1933 c) Ophiuroidea. The Danish Ingolf Expedition, 4, 1 - 120, 3 pls.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History) Zoology, 49, 1 - 162.","Koehler, R. (1896 a) Note preliminaire sur les ophiures recueillies pendant les campagnes de la ' Princesse Alice' Memoires de la Societe Zoologique de France, 9, 241 - 253.","Clark, H. L. (1915) Catalogue of Recent ophiurans: based on the collection of the Museum of Comparative Zoology. Memoirs of the Museum of Comparative Zoology, Harvard University, 25, 165 - 376, pls. 1 - 20. https: // doi. org / 10.5962 / bhl. title. 48598","Koehler, R. (1914) A contribution to the study of ophiurans of the United States National Museum. Bulletin of the United States National Museum, 84, 1 - 173 pls. 1 - 18. https: // doi. org / 10.5962 / bhl. title. 27414","Clark, H. L. (1911) North Pacific ophiurans in the collection of the United States National Museum. Bulletin of the United States National Museum, 75, 1 - 302, figs. 1 - 144. https: // doi. org / 10.5962 / bhl. title. 32556","Brogger, M. I. & O'Hara, T. D. (2015) Revision of some ophiuroid records from Argentina. Zootaxa, 3972 (3), 432 - 440. https: // doi. org / 10.11646 / zootaxa. 3972.3.8","Martynov, A. V. (2010) Reassessment of the classification of the Ophiuroidea (Echinodermata), based on morphological characters. I. General character evaluation and delineation of the families Ophiomyxidae and Ophiacanthidae. Zootaxa, 2697, 1 - 154. https: // doi. org / 10.11646 / zootaxa. 2697.1.1","Thuy, B. & Stohr, S. (2011) Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification. Zootaxa, 3013, 1 - 47. https: // doi. org / 10.11646 / zootaxa. 3013.1.1","Thuy, B. & Stohr, S. (2016) A New Morphological Phylogeny of the Ophiuroidea (Echinodermata) Accords with Molecular Evidence and Renders Microfossils Accessible for Cladistics. PLoSONE, 11, e 0156140. https: // doi. org / 10.1371 / journal. pone. 0156140","Numberger-Thuy, L. & Thuy, B. (2020) A new bathyal ophiacanthid brittle star (Ophiuroidea: Ophiacanthidae) with Caribbean affinities from the Plio-Pleistocene of the Mediterranean. Zootaxa, 4820, 19 - 30. https: // doi. org / 10.11646 / zootaxa. 4820.1.2","Verrill, A. E. (1899 b) Report on the Ophiuroidea collected by the Bahama expedition in 1893. Bulletin of the Laboratories of Natural History of the State of Iowa, 5, 1 - 88 pls. 1 - 8.","Lyman, T. (1878 a) Ophiurans and Astrophytons. Reports on the dredging operations of the U. S. coast survey Str. ' Blake'. Bulletin of the Museum of Comparative Zoology, Harvard University, 5, 217 - 238, 3 pls.","Verrill, A. E. (1899 a) North American Ophiuroidea. 1. Revision of certain families and genera of West Indian ophiurans. Transactions of the Connecticut Academy of Arts and Sciences, 10, 301 - 396. https: // doi. org / 10.5962 / bhl. part. 7032","Verrill, A. E. (1885) Notice of the remarkable marine fauna occupying the outer banks off the southern coast of New England, No. 11. American Journal of Science, 29, 149 - 157. https: // doi. org / 10.2475 / ajs. s 3 - 29.170.149"]}

Ophiolebes felli sp. nov. Fig. 7C–I, 8A–S http://zoobank.org/ urn:lsid:zoobank.org:act: E2AF7C6B-E83C-4F14-8DBD-D11F80E0A183 Type material. MD50 CP7, north-east of Île Amsterdam, 37° 47.2´S, 77° 38.98´E, 1680– 940m, Beam trawl, 9/7/1986, MNHN IE.2019.4746 (holotype), MNHN IE.2009.1569 (9 paratypes). Holotype description. Disc is 8.3 mm dd, arms are coiled distally but are at least 25 mm long. Both sides of the disc and the arms are covered in skin that obscures underlying plates. Disc is five lobed, constricted interradially, covered in skin with embedded low conical granules (Fig. 7D). The granules are largest on and between the radial shields and in the centre of the disc (0.27–0.3 mm dia), on the dorsal and ventral interradii they are smaller (0.18– 0.25 mm), sparser and separated by skin and small scales. The wide genital slits are contiguous with the first 2 arm segments (Fig. 7E). Oral shields are rhomboid, 1.5 times wider than long; adorals are almost of the same size, trapezoid, widest proximally, 2 times as wide as long, meeting broadly interradially, slightly tumid; teeth robust, pentagonal, pointed at tip, 3 conical papillae on the ventral margin of the oral plate, the adoral shield spine is slightly larger. DAPs are fan-shaped, as wide as long, with a rounded distal margin and acute angle proximally, separate. Some disc granules are present along the base of the arm and between DAPs of the first few segments. VAPs are wider than long, pentagonal with an obtuse proximal angle, rounded distal margin and straight lateral margins, separate. Arm spines are rounded in cross section and tapering to a blunt rounded tip, rugose but not thorny. First segments have 3 short spines, 4 on next 2 segments; beyond the disc there are 5–6 arm spines, uppermost to as long as a segment, lower spines 2/3 to half as long (Fig. 7F). Near the arm tip, the 3 spines become slender, subequal, less than a segment long and have thorns on the ventral side (Fig. 7G). Tentacle pores are small with a tiny pointed tentacle scale on proximal segments. Paratype variations. 4.5–5.5 mm dd (Fig. 7H–I). On one broken specimen, a vertical row of 5 flattened teeth are visible with a rounded distal edge. On some specimens there are only 2 lateral oral papillae on some jaws. The tentacle scales are difficult to see and rare on many specimens. Paratype ossicle description. Proximal LAPs (Fig. 8A–B) are approximately as high as long, of rounded outline, tumid, thick, with strongly convex distal edge; ventral edge convex, not protruding; dorsal edge oblique, very weakly concave; outer surface with coarsely meshed stereom, with trabecular intersections transformed into small, inconspicuous tubercles, no vertical striation; outer proximal edge with band of more finely meshed stereom, with a single, poorly defined spur in the dorsal half of the proximal edge. Spine articulations (Fig. 8C) are freestanding in a continuous vertical row on a raised distal portion of the LAP, ear-shaped, relatively small, composed of proximally merged dorsal and ventral lobes enclosing a large muscle opening and a smaller nerve opening, with a weakly developed sigmoidal fold. Inner side of LAPs with a large, prominent, moderately well-defined, digit-1-shaped vertebral articular ridge; poorly-defined spur in the dorsal half of the inner distal edge corresponding to the spur on the outer distal edge of the LAP; tentacle notch small, oblique, shallow. Very small, inconspicuous perforations occur close to the ventro-distal tip of the vertebral articular structure. Vertebrae (Fig. 8G–K) compact, tumid, with small, narrow distal and proximal muscle fossae; large, hourglassshaped (streptospondylous) distal and proximal articulations; oblique P-shaped lateral articulation structure corresponding with articular structure on the inner side of the LAP; large, deep dorsal and ventral furrows, with small, inconspicuous podial basins. Oral plates (Fig. 8O) split into distal and proximal halves, approximately as high as long, with adradial muscle fossa lining the ventro-distal edge of articulation area. Dental plates (Fig. 8P) are undivided, narrow, rounded, with single row of small, shallow tooth sockets surrounded by weakly-defined protruding ring. Abradial genital plates (Fig. 8Q) are almost as long as the adradial ones (Fig. 8R), relatively thick, bar-like, without ridges or groves and with a straight adradio-distal tip. Radial shields (Fig. 8S) are strongly elongated, isosceles-triangular outline with a slightly oblique proximal tip; no ornamentation on the outer surface. Proximal dorsal arm spines (Fig. 8D), ventral arm spines (Fig. 8E), tentacle scales (Fig. 8F), disc granules (Fig. 8L), ventral arm plate (Fig. 8M) and dorsal arm plate (Fig. 8N) are also figured. Remarks. This species is similar to the Atlantic species O. baccata Koehler, 1921. However, that species is generally smaller, to 4.5 m dd, with smaller (0.2 mm dia) disc granules, and distally lobed oral shields (Paterson 1985). Other similar species include O. vestitus Lyman, 1878 from off southern Chile (273–940 m) and O. mortenseni A.H. Clark, 1916 from the Galapagos (729 m). These differ in having a more even covering of disc granules that have the form of short cylindrical stumps with a crown of thorns. The species named as “ Ophiacantha sp. ” in Manso (2010, fig. 6) is also likely to be either O. vestitus or O. mortenseni. The type of Ophiolebes is O. scorteus Lyman, 1878b from off subantarctic Marion Island (279–576 m) which has not been reported since. The granules on that species are smaller and restricted to the radial shields with only a few occurring marginally. The other Atlantic species, O. pachyphylax H.L. Clark, 1915 has much longer arm spines (to 2 segments) and obvious disc plates bearing the granules, and O. retecta Koehler, 1895 has DAPs that are split into two sections (also present in O. antarctica Koehler, 1901). There are a number of North Pacific species also referred to Ophiolebes by Clark (1911), Matsumoto (1917), Djakonov (1949) and Irimura (1982) but none of these have the low disc granules embedded in thick skin of the present species. The New Zealand species, O. comatulina McKnight, 2003, has much longer disc spines. All these species require reassessment of their generic placement. Conversely, Ophiacantha yaldwyni Fell, 1958 from southern Australia and New Zealand is similar morphologically to the current species and is herein transferred to Ophiolebes, sharing the tiny tentacle scale, short arm spines, and conical granules embedded in disc skin (Fell, 1958). It differs from the new species in having divergent thorns arising from the centre of the disc granules, thorns at the tip of the arm spines and numerous lateral oral papillae and adoral shield spines. The MD 50 specimens were found epizoic on a black coral (Fig. 7C). Etymology. Named after H.B. Fell, a pioneer of echinoderm taxonomy and biogeography in New Zealand, who promoted the idea of long distance dispersal around southern oceans on the “West Wind Drift” (Fell 1962)., Published as part of O'Hara, Timothy D. & Thuy, Ben, 2022, Biogeography and taxonomy of Ophiuroidea (Echinodermata) from the Îles Saint- Paul and Amsterdam in the southern Indian Ocean, pp. 1-49 in Zootaxa 5124 (1) on pages 21-24, DOI: 10.11646/zootaxa.5124.1.1, http://zenodo.org/record/6404674, {"references":["Koehler, R. (1921) Echinodermes (asteries, ophiures, echinides, et crinoides) des dernieres campagnes de la Princesse-Alice et de l'Hirondelle II. Bulletin de l'Institut Oceanographique, Monaco, 396, 1 - 8.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History) Zoology, 49, 1 - 162.","Clark, A. H. (1916) On a new starfish and five new brittle-stars from the Galapagos Islands. Annals and Magazine of Natural History, 18, 115 - 122. https: // doi. org / 10.1080 / 00222931608693831","Manso, C. L. C. (2010) Deep-water Ophiuroidea (Echinodermata) from off Chile in the Eastern South Pacific. Biota Neotropica, 10, 1 - 15. https: // doi. org / 10.1590 / S 1676 - 06032010000200023","Lyman, T. (1878 b) Ophiuridae and Astrophytidae of the exploring voyage of H. M. S. Challenger, under Prof. Sir Wyville Thomson, F. R. S. Part 1. Bulletin of the Museum of Comparative Zoology, Harvard University, 5, 65 - 168, 10 pls.","Clark, H. L. (1915) Catalogue of Recent ophiurans: based on the collection of the Museum of Comparative Zoology. Memoirs of the Museum of Comparative Zoology, Harvard University, 25, 165 - 376, pls. 1 - 20. https: // doi. org / 10.5962 / bhl. title. 48598","Koehler, R. (1895) Dragages profonds executes a bord du Caudan dans le Golfe de Gascogne Revue biologique du Nord de la France, 7, 439 - 496.","Koehler, R. (1901) Note preliminaire sur quelque Ophiures nouvelles provenant des compagnes de la Princesse Alice. Bulletin de la Societe Zoologique de France, 26, 222 - 231.","Clark, H. L. (1911) North Pacific ophiurans in the collection of the United States National Museum. Bulletin of the United States National Museum, 75, 1 - 302, figs. 1 - 144. https: // doi. org / 10.5962 / bhl. title. 32556","Matsumoto, H. (1917) A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College of Science, Imperial University Tokyo, 38, 1 - 408, pls. 1 - 7.","Djakonov, A. M. (1949) Key to the Echinoderms of the Far Eastern Seas. Izvestiya Tikhookeanskogo Instituta Rybnogo Khozyaistva i Okeanografii, 30, 4 - 127.","Irimura, S. (1982) The Brittle-stars of Sagami Bay. Biological Laboratory, Imperial Household, Tokyo, 95 + 53 pp, 15 leaves of pls.","McKnight, D. G. (2003) New brittle-stars (Echinodermata: Ophiuroidea) from New Zealand waters. Zootaxa, 352, 1 - 36. https: // doi. org / 10.11646 / zootaxa. 352.1.1","Fell, H. B. (1958) Deep-sea echinoderms of New Zealand. Zoological Publications of the Victoria University Wellington, 24, 1 - 40.","Fell, H. B. (1962) West-wind-drift dispersal of echinoderms in the southern hemisphere. Nature, 193, 759 - 761. https: // doi. org / 10.1038 / 193759 a 0"]}

Ophiacantha veterna Koehler, 1907a Fig. 6A–B Ophiacantha veterna Koehler, 1907a: 41–43.— Koehler 1909: 189–190, pl. 29(3–4). — Koehler 1921 b: 2.— Martynov & Litvinova 2008: 96–97, fig. 11d. Ophiacantha enopla veterna.— Paterson 1985: 37, fig. 16.— Stöhr & Segonzac 2005: 392. Material examined. MD 50 CP7, MNHN IE.2009.1562 (2). MD 50 CP113, MNHN IE.2009.1563 (1). Distribution. Arctic (1992–1995 m), NE Atlantic (1350–2669 m), E Atlantic (1004–1679 m), SPA (940–1680 m). Remarks. The MD 50 specimens are 6.5–7.0 mm dd, disc pentagonal or slightly indented interradially, with margin covered in small rugose granules and centre with small cylindrical spines with terminal thorns, radial shields raised and rib like with oval distal section exposed (Fig. 6A), oral shields trapezoid to hemispherical, two times as wide as long, three to four conical to capitate rugose oral papillae (Fig. 6B), DAPs fan to kite-shaped and separate, to eight arm spines with tiny thorns, upper to three segments long and one tiny spiniform thorny tentacle scale. They are morphologically consistent with material from the North Atlantic including the type description. Although Paterson (1985) considered this species to be a subspecies of Ophiacantha enopla Verrill, 1885, Martynov & Litvinova (2008) re-established O. veterna as a full species. Paterson’s (1985) record of this species from 101 m is a depth outlier that requires re-examination. All other records are from 1000–2700 m., Published as part of O'Hara, Timothy D. & Thuy, Ben, 2022, Biogeography and taxonomy of Ophiuroidea (Echinodermata) from the Îles Saint- Paul and Amsterdam in the southern Indian Ocean, pp. 1-49 in Zootaxa 5124 (1) on pages 16-17, DOI: 10.11646/zootaxa.5124.1.1, http://zenodo.org/record/6404674, {"references":["Koehler, R. (1907 a) Note preliminaire sur quelques Asterias et Ophiures provenant des campagnes de la ' Princesse Alice'. Bulletin de l'Institut Oceanographique, Monaco, 99, 1 - 47.","Koehler, R. (1909) Echinodermes provenant des campagnes du yacht ' Princesse Alice' (Asteries, Ophiures, Echinides et Crinoides). Resultats des Scientifiques Campagnes du Prince de Monaco, 34, 1 - 317, 32 pls.","Koehler, R. (1921) Echinodermes (asteries, ophiures, echinides, et crinoides) des dernieres campagnes de la Princesse-Alice et de l'Hirondelle II. Bulletin de l'Institut Oceanographique, Monaco, 396, 1 - 8.","Martynov, A. V. & Litvinova, N. M. (2008) Deep-water Ophiuroidea of the northern Atlantic with descriptions of three new species and taxonomic remarks on certain genera and species. Marine Biology Research, 4, 76 - 111. https: // doi. org / 10.1080 / 17451000701840066","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History) Zoology, 49, 1 - 162.","Stohr, S. & Segonzac, M. (2005) Deep-sea ophiuroids (Echinodermata) from reducing and non-reducing environments in the North Atlantic Ocean. Journal of the Marine Biological Association of the United Kingdom, 85, 383 - 402. https: // doi. org / 10.1017 / S 0025315405011318 h","Verrill, A. E. (1885) Notice of the remarkable marine fauna occupying the outer banks off the southern coast of New England, No. 11. American Journal of Science, 29, 149 - 157. https: // doi. org / 10.2475 / ajs. s 3 - 29.170.149"]}

Ophiolimna bairdi (Lyman, 1883) Fig. 6G–H Ophiacantha bairdi Lyman, 1883: 256, pl. 5(70–72).— Mortensen 1933c: 30–31. Ophiolimna bairdi.— Paterson 1985: 60, fig 24.— Martynov & Litvinova 2008: 100–101, fig. 17a. Material examined. MD 50 CP7, MNHN IE.2009.1570 (6). MD 50 CP152, MNHN IE.2009.1571 (1). Distribution. Arctic (664–2750 m), NW Atlantic (1910–2592 m), NE Atlantic (609–2910 m), NW Pacific (48–2207 m), NE Pacific (520–2300 m), E Atlantic (1975–2330 m), E Indo-W Pacific (244–280 m), E Pacific (960– 1819 m), S America (2945–2958 m), South Africa (1300 m), S Australia (1428–2010 m), New Zealand (1318–1327 m). SPA (940–1880 m). Remarks. The SPA specimens have been identified here as the northern hemisphere O. bairdi, rather than O. antarctica (Lyman 1879) that has been recorded from Antarctic and subantarctic regions, on both morphological and bathymetric evidence. The specimens have a mix of granules and short conical stumps on the disc (Fig. 6G), characteristic of O. bairdi, rather than the uniform granule-shaped armament of O. antarctica. Moreover, records from the north Atlantic have been generally found at 1000–2500 m, whereas those in the southern polar regions are generally above 1000 m. Phylogenetic evidence in Christodoulou et al. (2019) suggests that tropical Indo-Pacific specimens identified by O’Hara and Stöhr (2006) as O. antarctica are a separate species related to O. perfida (Koehler 1904). Specimens from the Galapagos Islands, although appearing broadly similar in appearance, are placed in a separate genetic lineage (Christodoulou et al. 2019, DNA code=NA064-015-13-A_EP_3)., Published as part of O'Hara, Timothy D. & Thuy, Ben, 2022, Biogeography and taxonomy of Ophiuroidea (Echinodermata) from the Îles Saint- Paul and Amsterdam in the southern Indian Ocean, pp. 1-49 in Zootaxa 5124 (1) on page 28, DOI: 10.11646/zootaxa.5124.1.1, http://zenodo.org/record/6404674, {"references":["Lyman, T. (1883) Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Caribbean Sea in 1878 - 79, and among the Atlantic coast of the United States during the summer of 1880, by the U. S. Coast Survey steamer Blake, Commander J. R. Bartlett, U. S. N., commanding. XX. Report on the Ophiuroidea. Bulletin of the Museum of Comparative Zoology, Harvard University, 10, 227 - 287 pls. 1 - 8.","Mortensen, T. (1933 c) Ophiuroidea. The Danish Ingolf Expedition, 4, 1 - 120, 3 pls.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History) Zoology, 49, 1 - 162.","Martynov, A. V. & Litvinova, N. M. (2008) Deep-water Ophiuroidea of the northern Atlantic with descriptions of three new species and taxonomic remarks on certain genera and species. Marine Biology Research, 4, 76 - 111. https: // doi. org / 10.1080 / 17451000701840066","Lyman, T. (1879) Ophiuridae and Astrophytidae of the exploring voyage of H. M. S. Challenger under Prof. Sir Wyville Thomson, F. R. S. Part 2. Bulletin of the Museum of Comparative Zoology, Harvard University, 6, 17 - 83, pls. 11 - 19.","Christodoulou, M., O'Hara, T. D., Hugall, A. F. & Arbizu, P. M. (2019) Dark Ophiuroid Biodiversity in a Prospective Abyssal Mine Field. Current Biology, 29 (e 3), 3909 - 3912.","O'Hara, T. D. & Stohr, S. (2006) Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. Tropical Deep-Sea Benthos, 24, 33 - 141.","Koehler, R. (1904) Ophiures de mer profonde. Siboga-Expeditie, 45, 1 - 176 pls. 1 - 36."]}

Ophiolebes paulensis sp. nov. Fig. 9A–C, 10A–P http://zoobank.org/ urn:lsid:zoobank.org:act: F57E6CCA-DD72-4FED-80BB-439479B0C13D Type material. MD50 CP7, north-east of Île Amsterdam, 37° 47.2´S, 77° 38.98´E, 1680– 940m, Beam trawl, 9/7/1986, MNHN IE.2009.1566 (holotype), MNHN IE.2009.1567 (5 paratypes). Other material examined. MD 50 DC91, MNHN IE.2009.1568 (2). Comparative Material. Ophiolebes comatulina McKnight, 2003: NZOI / E728, 37° 37.5´S, 177° 12.198´E, 688– 432 m, 25/3/1967, holotype, NIWA 3343 (1). EBISCO/DW2603, Plateau des Chesterfield, 19° 36´S, 158° 43.0005´E, 568–570 m, 18/10/2005, MNHN IE. 2013.6311 (1). EBISCO/DW2613, Plateau des Chesterfield, 19° 37´S, 158° 41.9998´E, 519–522 m, 19/10/2005, MNHN IE. 2013.6287 (2). KAH9907/37, Ritchie Hill Seamount, 39° 29.44´S, 178° 25.05´E to 39° 28.51´S, 178° 25.48´E, 1000– 980 m, 3/6/1999, NIWA 41434 (1). Holotype description. Disc is 5.5 mm dd, the longest attached arm piece is ~ 10 mm long; disc is tumid radially and sunken interradially, covered in rounded non-imbricating scales, embedded in thin skin, ~ 0.5 mm dia, minutely perforated, fully contiguous and more polygonal over the radial shields, slightly separated in the centre of the disc (Fig. 9A). Scales support one, rarely 2, disc spines, tapered conical to cylindrical, thorny on blunt tip, 3 times as high as wide, ~ 0.3 mm high in centre, smaller near margin, base smooth, upper half with more sculptured stereom and some small thorns. Radial shields are evidently bar-like but covered by skin and scales. Ventral disc (Fig. 9B) surfaces are covered in similar scales, 4–5 rows from oral shield to margin, marginal scales with short conical stumps, 2 times as long as wide, but extend only half the way to the oral shield. Genital slits extend from oral shield for 2.5 arm segments, stopping short of the margin. Genital plates visible externally, adradial plates with a short base and broadly curved, abradial ones abut it closely, extending for half the length of the slit. Jaws are as long as wide, supporting a tapered ventralmost tooth and three spiniform oral papillae, all arising from the oral plate, the proximally pointed inner one representing the infradental papilla, the obliquely pointed middle one the lateral oral papilla and the distal one the adoral shield spine (following Hendler 2018, fig. 16). All papillae are pitted with tiny thorns near the tip, hollow. Four are teeth visible from the external ventral surface, similar shape to the ventralmost one. Oral plates are raised near the papillae and sunken slightly behind. Second oral podia arise from a naked patch between the adoral shields and first VAP. Adoral shields are 3 times as wide as long, sausage shaped, with concave inner and convex outer margins, rounded outer ends, fully contiguous interradially, separated radially by the first VAP. Oral shields are pentagonal, with concave proximolateral margins, obtuse proximal angle, slightly tapering distolateral sides and a truncate distal margin, the distal section of the plate is sunken down to the level of the ventral disc, central section tumid in the madreporite. First 1–2 DAPs are triangular, wide as long, contiguous. Succeeding DAPs are rounded triangular, with convex distal margin, and long tapered proximolateral sides, with a small truncate proximal margin, sometimes contiguous, or with a small skin-covered bare patch or a small supplementary plate between plates, typically 1.5 to 2 times as long as wide. LAPs are roughly quadrangular, contiguous, arm spine ridge raised slightly, contiguous ventrally but not dorsally. VAPs on the first segment are 1.5 times as long as wide, widest proximally, with straight proximolateral edges and a straight to concave proximal edge, concave sides (to accommodate the adoral shields), straight distolateral edges and a truncate to rounded distal margin, just touching the proximal angle of the 2nd VAPs, 2nd VAPs are fanshaped with straight proximolateral edges, an acute proximal angle and a rounded distal edge, widest at the distal 1/3 of the plate. Tube foot openings are very small, rounded, the proximolateral edges of the VAPs are not concave around the pore. Succeeding plates become as wide as long, well separated from their neighbours, widest in the middle of the plate, and notched around the pore, the distal edge can become centrally concave on distal segments. Arm spines are rounded, tapering to a blunt tip, hollow, with sculptured stereom but generally no thorns, do not meet basally even on basal segments just free of the disc. Three arm spines occur on the first segments, four on second and third, four on the fourth segment, then five on segment five and six, just free of the disc, an occasional segment has six spines in the middle of the arm. Upper arm spines are generally longest, particularly on the 5th and 6th segment, to 1.7 mm, 2nd spines (from dorsal) about half its length, lower three 1/4 as short and more slender. From about the 10th segment, the upper spine reduces in size becoming subequal with the others, and the lower arm spines become shorter and stouter with proximally directed thorns (Fig. 9C). Tentacle scales absent proximally (or rubbed off), a tiny pointed scale on the ventral edge of LAP in the middle of the arm, 1/10 the length of the VAP. Colour (preserved). light brown, the tube feet and tips of the arm spines (skin covered?) are darker brown. Paratype variations. Discs vary from 4.0– 5.5 mm dd, longest arm fragment is 12.5 mm on a 5 mm dd specimen. The distal section of the bar-like radial shields are exposed on some radii. Some specimens have long disc stumps (to five times height/dia) with stereom extending into short thorns around the spine stem as well as the tip. Paratype ossicle description. Proximal LAPs (Fig. 10A–B) are slightly higher than long, of rounded outline, relatively thin, with strongly convex distal edge; ventral edge oblique, straight, slightly protruding; dorsal edge slightly concave as a result of a weak constriction; outer surface with coarsely meshed stereom, devoid of tubercles or a vertical striation; outer proximal edge with a proximalwards-pointed spur, entirely lined by a band of more finely meshed stereom. Spine articulations (Fig. 10C) are freestanding in a continuous vertical row on a strongly raised distal portion of the LAP, ear-shaped, moderately large, composed of proximally merged dorsal and ventral lobes enclosing nearly equal-sized muscle and nerve openings and with a moderately well-developed sigmoidal fold. Inner side of LAPs have a large, prominent, well-defined, slender digit-1-shaped vertebral articular ridge; poorly-defined spur in the dorsal half of the inner distal edge corresponding to the protruding spur on the outer distal edge of the LAPs; tentacle notches are small, oblique, shallow. Very small, inconspicuous perforations occur close to the ventro-distal tip of the vertebral articular structure. Vertebrae (Fig. 10E–I) have wide triangular dorsal fossae and with relatively large ventral muscle fossae on both distal and proximal faces; distal articulations are relatively large, hour-glass-shaped (streptospondylous) with a very small ventral projection of the middle saddle; hourglass-shaped proximal articulation with a vertical pore in the ventral half; oblique L-shaped lateral articulation structure corresponding to articular structure on the inner side of the LAP; dorso-distal muscle fossae are deeply carved into the lateral side of the vertebra; relatively large dorsal and ventral furrows, with moderately large podial basins. Oral plates (Fig. L) are split in distal and proximal halves, approximately as high as long, with adradial muscle fossa lining the ventro-distal edge of articulation area. Dental plates (Fig. 10K) are undivided, very narrow, rounded, with single row of small, shallow tooth sockets surrounded by weakly-defined protruding ring. Abradial genital plates (Fig. 10N) shorter than the adradial ones (Fig. 10O), slender, bar-like without ridges or groves and with a straight adradio-distal tip. Radial shields (Fig. 10P) are strongly elongated, bar-like, slightly bent, devoid of outer surface ornamentation. A proximal dorsal arm spine (Fig. 10D), disc spine (Fig. 10M), and ventral arm plate (Fig. 8J) are also figured. Distribution. SPA (940–1680 m). Remarks. This species is similar to Ophiolebes comatulina McKnight, 2003 known from NE New Zealand (432–1000 m) and the Chesterfield Bank, New Caledonia (519–570 m) (O’Hara unpublished data). Ophiolebes comatulina differs in having diamond shaped oral shields (tapering to a distal angle) and a stout tentacle scale on proximal segments, 1/4 the length of the VAP.All the O. comatulina specimens to date have been found on crinoids. Although there is now no evidence of crinoid material with the MD50 Ophiolebes paulensis sp. nov. specimens, the type locality (stn CP7) was the only sample from the survey recorded with crinoids (Arnaud 1990). Other Ophiolebes species have disc granules and/or short spines on the disc (see above) rather than tall stumps. The South African species Ophiosemnotes corynephora (H.L. Clark, 1923) has superficially similar disc spines to the new species but differs in having wide exposed radial shields. Etymology. Named after the Île Saint-Paul.

O'Hara, Timothy D., Thuy, Ben (2022): Biogeography and taxonomy of Ophiuroidea (Echinodermata) from the Îles Saint- Paul and Amsterdam in the southern Indian Ocean. Zootaxa 5124 (1): 1-49, DOI: https://doi.org/10.11646/zootaxa.5124.1.1

Ophiosemnotes conferta (Koehler 1922b) Fig. 7A–B Ophioripa conferta Koehler, 1922b: 19–21, pl. 85(9–13). Ophiomitrella falklandica Mortensen, 1936: 256–259, figs. 8c–d, pl. 7(5) [according to O’Hara, 1990]. Ophiomitrella conferta.— Madsen 1967: 127.— O’Hara 1990: 299–300, fig. 2c–d, f–g.— O’Hara & Stöhr 2006: 90–92, fig. 10f–h, 18n–o. Material examined. MD 50 CP7, MNHN IE.2009.1574 (5). MD 50 CP113, MNHN IE.2009.1575 (1). MD 50 DC146, MNHN IE.2009.1576 (14). Distribution. East Indo-West Pacific (480–1019 m), South America (79–680 m), Kerguelen (247 m), southern Australia (590–2340 m), New Zealand (27–1365 m), Antarctic (74–835 m). SPA (420–1680 m). Remarks. The MD 50 specimens are up to 7 mm dd, the disc scales coarse and imbricating with 1–2 stumps, to 0.6 mm high, vase-shaped to capitate, rough/thorny at tip (Fig. 7A). The radial shields are broadly triangular, and distally contiguous. There are three long cylindrical, blunt tipped oral papillae, sunken oral plates, and rhomboid oral shields. The VAPs are small and separate, with a notched distal edge (Fig. 7B). The LAPs bear up to six rounded arm spines, with a finely thorny surface, uppermost are longest, to 1.3 mm long, two times the length of a segment. The lowest arm spines have conspicuous ventrally directed thorns distally. The single tentacle scale is lanceolate. These specimens are similar to the Southern Ocean O. conferta complex, characterised by the large capitate disc stumps. Following Madsen (1967), this complex has been placed in the genus Ophiomitrella Verrill, 1899b. However, the molecular phylogeny of O’Hara et al. (2017) shows that species placed in Ophiomitrella form several unrelated clades, one of which is a monophyletic group that contains O. conferta, O. ingrata Koehler, 1908, O. corynephora H.L. Clark, 1923 and O. clavigera (Ljungman 1865). There are two other available genus-level names that have been applied to at least one of these species. Matsumoto (1917) placed O. clavigera in his new genus Ophiosemnotes along with several North Pacific species including the type species O. tylota H.L. Clark, 1911. Koehler (1922b) originally placed O. conferta in Ophioripa Koehler, 1922a with type species O. marginata from the Philippines. We have not obtained DNA sequence for O. tylota or O. marginata, however, the sequenced specimens from this clade do conform to both generic morphological diagnoses, having large disc scales, sparse disc stumps, wide radial shields, small widely separate VAPs and DAPs, and short robust arm spines. They are clearly differentiated from the type of Ophiomitrella, O. laevipellis Lyman, 1883, which has small disc plates and tiny disc granules (mostly absent), widely separated radial shields, wide ventral arm plates, and numerous long slender arm spines. Consequently, we use the genus-name Ophiosemnotes for the O. conferta group as it has priority over Ophioripa, which may be a synonym. Another Ophiomitrella species that can be assigned to Ophiosemnotes is O. hamata Mortensen, 1933a. The inclusion of O. chilensis Mortensen, 1952 is questionable given the tiny tentacle scale and requires further investigation. Two species O. tylota and O. pachybactra share many features with O. conferta, however, the other North Pacific species now referred to Ophiosemnotes show a range of morphologies with several having tiny disc granules and naked circular separate radial shields (O. diaphora H.L. Clark, 1911, O. paucispina H.L. Clark, 1911) or no granules at all (O. brevispina H.L. Clark, 1911) and probably belong to other genera. It is likely that there are several species within the O. conferta complex (O’Hara et al. 2017; O’Hara et al. 2013), which has been reported from upper bathyal depths from Antarctica to New Caledonia (O’Hara & Stöhr 2006). The disc stumps in particular are polymorphic, varying from spherical to capitate. Many Ophiosemnotes species, including O. conferta, are viviparous (O’Hara 1990) which potentially limits dispersal and species ranges. A thorough phylogeographical study of the complex is required to sort out species boundaries., Published as part of O'Hara, Timothy D. & Thuy, Ben, 2022, Biogeography and taxonomy of Ophiuroidea (Echinodermata) from the Îles Saint- Paul and Amsterdam in the southern Indian Ocean, pp. 1-49 in Zootaxa 5124 (1) on page 20, DOI: 10.11646/zootaxa.5124.1.1, http://zenodo.org/record/6404674, {"references":["Koehler, R. (1922 b) Echinodermata: Ophiuroidea. Scientific Reports. Australasian Antarctic Expedition, Series C, 8 (2), 1 - 98, pls. 76 - 90.","Mortensen, T. (1936) Echinoidea and Ophiuroidea. Discovery Reports, 12, 199 - 348, 9 pls. https: // doi. org / 10.5962 / bhl. part. 8051","O'Hara, T. D. (1990) New records of Ophiuridae, Ophiacanthidae and Ophiocomidae (Echinodermata: Ophiuroidea) from south-eastern Australia. Memoirs of the Museum of Victoria, 50, 287 - 305. https: // doi. org / 10.24199 / j. mmv. 1990.50.04","Madsen, F. J. (1967) Ophiuroidea. Report of the British, Australian and New Zealand Antarctic Research Expedition 1929 - 1931, Series B, 9, 123 - 145.","O'Hara, T. D. & Stohr, S. (2006) Deep water Ophiuroidea (Echinodermata) of New Caledonia: Ophiacanthidae and Hemieuryalidae. Tropical Deep-Sea Benthos, 24, 33 - 141.","Verrill, A. E. (1899 b) Report on the Ophiuroidea collected by the Bahama expedition in 1893. Bulletin of the Laboratories of Natural History of the State of Iowa, 5, 1 - 88 pls. 1 - 8.","O'Hara, T. D., Hugall, A. F., Thuy, B., Stohr, S. & Martynov, A. V. (2017) Restructuring higher taxonomy using broad-scale phylogenomics: the living Ophiuroidea. Molecular Phylogenetics and Evolution, 107, 415 - 430. https: // doi. org / 10.1016 / j. ympev. 2016.12.006","Koehler, R. (1908) Asteries, ophiures et echinides de l'Expedition Antarctique Nationale Ecossaise Report on the Scientific Results of the Voyage of the S. Y. Scotia Zoology, 13, 193 - 313, 16 pls.","Clark, H. L. (1923) The echinoderm fauna of South Africa. Annals of the South African Museum, 13, 221 - 435, pls. 8 - 23.","Ljungman, A. V. (1865) Tillagg till kannedom af Skandinaviens Ophiurider Ofversigt af Kongl. Vetenskaps-Akademiens Forhandlingar, Stockholm, 21, 359 - 370.","Matsumoto, H. (1917) A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College of Science, Imperial University Tokyo, 38, 1 - 408, pls. 1 - 7.","Clark, H. L. (1911) North Pacific ophiurans in the collection of the United States National Museum. Bulletin of the United States National Museum, 75, 1 - 302, figs. 1 - 144. https: // doi. org / 10.5962 / bhl. title. 32556","Koehler, R. (1922 a) Contributions to the biology of the Philippine Archilepago and adjacent regions. Ophiurans of the Philippine seas and adjacent waters. Bulletin of the United States National Museum, 100, 1 - 486 pls. 1 - 103.","Lyman, T. (1883) Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Caribbean Sea in 1878 - 79, and among the Atlantic coast of the United States during the summer of 1880, by the U. S. Coast Survey steamer Blake, Commander J. R. Bartlett, U. S. N., commanding. XX. Report on the Ophiuroidea. Bulletin of the Museum of Comparative Zoology, Harvard University, 10, 227 - 287 pls. 1 - 8.","Mortensen, T. (1933 a) Echinoderms of South Africa (Asteroidea: Ophiuroidea). Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening, 93, 215 - 400, pls. 8 - 19.","Mortensen, T. (1952) Reports of the Lund University Chile Expedition 1948 - 1949. 3. Echinoidea and Ophiuroidea. Lunds Universitets Arsskrift, Neue Folge, 47, 1 - 22, pl. 1.","O'Hara, T. D., Smith, P. J., Mills, V. S., Smirnov, A. V. & Steinke, D. (2013) Biogeographical and phylogeographical relationships of the bathyal ophiuroid fauna of the Macquarie Ridge, Southern Ocean. Polar Biology, 36, 321 - 333. https: // doi. org / 10.1007 / s 00300 - 012 - 1261 - 9"]}

The ophiuroid genus Ophioplinthaca is well characterized by the deep incisions in the disc. Prior to this study, it contained 32 accepted species, but species limits and geographic distributions were not well understood. The manned submersible vehicle ‘Shenhaiyongshi’ was used to collect ophiuroid specimens from the deep-sea seamounts and cold seeps in the South China Sea and Northwest Pacific at 602–3600 m depth, during 2018 to 2020. The genus Ophioplinthaca was reviewed using both morphological data and a phylogenetic analysis, based on COI sequences. The taxonomic status of the genus Ophiophthalmus Matsumoto, 1917, a junior homonym of Ophiophthalmus Fitzinger, 1843 (a reptile) was clarified by proving prevailing usage of the ophiuroid name. A total of eight species were identified, including two new species, described asOphioplinthaca brachispinasp. nov. and Ophiophthalmus serratussp. nov., and two new records. The new species are characterized by unique features of the arm skeletons. Tabular keys to all Ophioplinthaca and Ophiophthalmus species are provided. Interspecific and intraspecific genetic distance of Ophioplinthaca species ranged from 2.32% to 19.72%, and from 0.26% to 0.90%, respectively. The data suggest that species of the genus Ophioplinthaca are more widely spread around the Northwest Pacific region deep-sea seamounts than previously known.

Family Ophiacanthidae Ljungman, 1867 Type genus Ophiacantha Müller & Troschel, 1842. Other genera Ophialcaea Verrill, 1899; Ophientrema Verrill, 1899; Ophiocanops Koehler, 1922; Ophiochondrus Lyman, 1869; Ophiohamus O’Hara & Stöhr, 2006; Ophiolebes Lyman, 1878; Ophiolimna Verrill, 1899; Ophiomitrella Verrill, 1899; Ophiomoeris Koehler, 1904; ‘ Ophiophthalmus ’ Matsumoto, 1917; Ophioplinthaca Verrill, 1899; Ophioripa Koehler, 1922; Ophiosemnotes Matsumoto, 1917; Ophiurothamnus Matsumoto, 1917. Description ARM. Arm shape unbranched; length 3× disc diameter, or length 3– 4× disc diameter, or length more than 4× disc diameter; covering without granules/spines/tubercles.Arm combs absent. Dorsal arm plate present. Accessory dorsal arm plate absent. Ventral arm plate present.Accessory ventral arm plate absent. Girdle of tiny hooks on the arms absent. Spines all similar in shape. Arm spine cross section round. The ratio of thickness of distal ⅓ of arm spine to maximum thickness (in a given cross-sectional plane) 0.6–0.9, or 0.9–1 (Ophiochondrus). Arm spines pointed; mainly lateral; predominantly erect, standing perpendicular to arm axis. Longest arm spines between one and two segments long (Ophiolimna), or longer than two segments. Tentacle scales present; pores visible along most of the arm; nearly as long as wide; shorter than the spine nearby; cross section oval. Position of lateral arm plate (LAP) arched (wrapped around the arm). Dorsal and/or ventral edge(s) of LAPs with constriction. Ventral position of LAP not projecting ventro-proximalwards. Ventro-distal tip of LAP not projecting ventralwards. Arm spine articulation with dorsal and ventral lobes; with a fully developed sigmoidal fold; arranged over entire distal LAP edge; dorsalwards increasing in size (Ophiacantha bidentata (Bruzelius, 1805), Ophiolimna), or all similar (Ophiacantha abyssicola G.O. Sars, 1872, Ophioplinthaca). Distance between spine articulations dorsalwards increasing. Nerve and muscle openings separated by small ridge if at all. Nerve opening smaller than muscle opening. DORSAL DISC. Disc circular; flat (about same level as arms) or high (above arm level) (Ophiochondrus). Integument obscuring plates. Dorsal disc with granules (Ophioplinthaca, Ophiolimna); with concealed primary plates; with scales; with spines (Ophiacantha, Ophiolimna) or without spines. Dorsal disc scale/plate without tubercles. Radial shield present; with spines and with granules; length between one third and half of the disc radius (O. bidentata, Ophioplinthaca), or length more than half of the disc radius (O. abyssicola, Ophiochondrus); isosceles (mirror-symmetric) triangular to pear-shaped, or bar-like. VENTRAL DISC. Gonads restricted to the disc or not restricted to the disc (Ophiocanops). Ventral interradii with spines (O. abyssicola) or with granules (O. bidentata, Ophiochondrus, with spine and granules in Ophiolimna). Scales on ventral interradii covering the whole area of an interradius. The number of scales on H line of an interradius about 7–14. Ventral teeth single. Infradental papillae on oral plate present. Buccal scales on OP absent. Accessory oral papillae on OP absent. Lateral oral papillae on OP present; single row of lateral papillae; spiniform. Adoral shield spine present. Lyman’s ossicle present. Oral shield covering less than one third of interradius; much wider than long. Madreporite one or multiple; with one pore or with numerous pores. Adoral shield meeting in front of the oral shield. Abradial genital plate not twisted. Number of genital slits one per bursa. Genital slit longer than half the length of an interradius. Genital papillae absent. Dental plate of equal width all over, or dorsal half widest (Ophiolimna); entire (single plate). Dental sockets slit-shaped; equal to or more than 50% of the width. At least one socket on DP as depression or perforation without septum. Teeth flat (with round or slightly pointed tip, but never spine-like). Teeth on DP arranged as single row. VERTEBRAE. Vertebrae zygospondylous; beyond segment 5 with short keel; without oral bridge., Published as part of Goharimanesh, Mona, Stöhr, Sabine, Mirshamsi, Omid, Ghassemzadeh, Fereshteh & Adriaens, Dominique, 2021, Interactive identification key to all brittle star families (Echinodermata; Ophiuroidea) leads to revised morphological descriptions, pp. 1-63 in European Journal of Taxonomy 766 (1) on pages 33-34, DOI: 10.5852/ejt.2021.766.1483, http://zenodo.org/record/5514587, {"references":["Koehler R. 1922. Ophiurans of the Philippine Seas and Adjacent Waters. US Government Printing Office, Washington. https: // doi. org / 10.5962 / bhl. title. 32917","Matsumoto H. 1917. A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College of Science, Imperial University, Tokyo 38: 1 - 408."]}

Ophiuroidea is the largest class among extant echinoderms, with over 2000 described species assigned to 33 families. Here, the first identification key to the recently revised classification was developed, and revised morphological descriptions were derived from it, expanding the previous short diagnoses. The key was built by analyzing internal and external skeletal characters of predominantly the type species of each family, including at least two mutually exclusive attributes per family. Various numeric and multistate characters were used to create a traditional as well as an interactive key using the DELTA and Xper software programs­. Illustrations (SEM and digital photos) are included in the key to facilitate the assessment of character states by users. Not only is it the first identification key to the families, according to the recently proposed new classification and the examined species, but this interactive key also assists users in understanding the family level taxonomy of brittle stars. The interactive key allows new characters and states to be added, when more species will have been analyzed, without the need to reconfigure the complete key (as may be necessary with conventional keys).

Ophiacantha pacifica Lütken & Mortensen, 1899: 166–167, pl. XV figs 4–6, pl. XVI fig. 11. ? Ophiacantha bathybia H.L. Clark, 1911: 233. (not examined) Figure 4A–D

Ophiacantha cosmica Lyman, 1878: 146, pl. 10 figs 251–254, 262–265, 269, 270. Figure 4E–G, Published as part of Stöhr, Sabine & O'Hara, Timothy D., 2021, Deep-sea Ophiuroidea (Echinodermata) from the Danish Galathea II Expedition 1950 - 52, with taxonomic revisions, pp. 505-529 in Zootaxa 4963 (3) on page 520, DOI: 10.11646/zootaxa.4963.3.6, http://zenodo.org/record/4704429, {"references":["Lyman, T. (1878) Ophiuridae and Astrophytidae of the \" Challenger \" expedition. Part I. Bulletin of the Museum of Comparative Zoology at Harvard, 5, 65 - 168."]}

The brittle star samples collected by the Danish cruise ‘Galathea II’ (1950–52) had not been studied completely. We examined the remaining deep-sea samples (>400 m) and present the species inventory, discussing taxonomic issues in relation to recent phylogenetic data. About 235 samples were examined, over 9,300 individuals, from 67 species and 74 sampling localities, at depths of 425–5340 m. The species complex Amphiophiura bullata (Thomson, 1877) is morphologically not well separated, but molecular data suggest at least two clades. We propose to apply A. bullata for Atlantic and Australian populations and A. convexa (Lyman, 1878) for the North Pacific clade. We consider A. bullata pacifica Litvinova, 1971 conspecific with A. convexa. Ophiuroglypha irrorata (Lyman, 1878) and its subspecies are a polyphyletic group with unclear morphological boundaries. We propose to transfer Ophiura ossiculata (Koehler, 1908), Ophiura plana (Lütken & Mortensen, 1899) and Ophiura scomba Paterson, 1985 to Ophiuroglypha. Silax Fell, 1962, until now synonymised with Amphioplus Verrill, 1899, is proposed as a valid genus with the species S. verrilli (Lyman, 1879), S. consors (Koehler, 1908), S. daleus (Lyman, 1879), S. patulus (Lyman, 1879) and S. magnificus (Koehler, 1907). Triplodia Turner & Hallen, 2011 (a replacement name for Triodia A. M. Clark, 1970, due to homonymy) is synonymised with Silax, and possible specimens of its type species Triodia abdita A. M. Clark, 1970 are analysed. The species limits of Ophiacantha cosmica Lyman, 1879 and Ophiacantha pacifica Lütken & Mortensen, 1899 could not be confirmed morphologically, but published molecular data suggest two clades. We propose to apply O. pacifica to the Northern/Central Pacific population and O. cosmica to the Southern Pacific/Antarctic population.

Identifiable remains of large deep-sea invertebrates are exceedingly rare in the fossil record. Thus, every new discovery adds to a better understanding of ancient deep-sea environments based on direct fossil evidence. Here we describe a collection of dissociated skeletal parts of ophiuroids (brittle stars) from the latest Pliocene to earliest Pleistocene of Sicily, Italy, preserved as microfossils in sediments deposited at shallow bathyal depths. The material belongs to a previously unknown species of ophiacanthid brittle star, Ophiacantha oceani sp. nov. On the basis of morphological comparison of skeletal microstructures, in particular spine articulations and vertebral articular structures of the lateral arm plates, we conclude that the new species shares closest ties with Ophiacantha stellata, a recent species living in the present-day Caribbean at bathyal depths. Since colonization of the deep Mediterranean following the Messinian crisis at the end of the Miocene was only possibly via the Gibraltar Sill, the presence of tropical western Atlantic clades in the Plio-Pleistocene of the Mediterranean suggests a major deep-sea faunal turnover yet to be explored.

Genus Ophiacantha Müller & Troschel, 1842 Remarks. Ophiacantha is one of the most species-rich (Stöhr et al. 2012) and heterogeneous genera among the living ophiuroids (O’Hara & Stöhr 2006; Thuy 2013). Latest molecular evidence confirmed earlier suspicions that the genus, as currently defined, represents a polyphyletic amalgam of species (O’Hara et al. 2017, 2018) that should be subdivided into several genus-level clades. Previous studies already hinted at morphologically coherent species groups within Ophiacantha potentially representing such genus-level clades (O’Hara & Stöhr 2006; Thuy 2013). A revision of Ophiacantha and allied genera combining molecular and morphological evidence by far exceeds the scope of the present paper. We therefore preliminarily assign the species described herein to Ophiacantha, emphasizing, however, that it belongs to a separate species group than the type species O. bidentata.

Ophiacantha oceani sp. nov. Figure 2 urn:lsid:zoobank.org:act: F80B0B8E-7E60-4666-B682-E59E0B50A7A6 Etymology. Species named in honour of progressive metal band ���The Ocean���. Musicians who so skillfully combine arts and science, composing albums like ���Precambrian��� (with songs named after the periods of the Precambrian), ���Pelagial��� (with songs named after the bathymetric subdivisions of the water column) and ���Phanerozoic��� as well as the song ���Turritopsis dohrnii��� referring to the immortal jellyfish from the Mediterranean, are more than deserving of being immortalized in the fossil record. Holotype. MnhnL (Mus��e national d���histoire naturelle, Luxembourg) OPH074, dissociated lateral arm plate. Paratypes. MnhnL OPH075 and OPH076, two dissociated lateral arm plates. Additional material. MnhnL OPH077, ten dissociated lateral arm plates. Diagnosis. Species of Ophiacantha with lateral arm plates showing a very strong constriction; weak vertical striation close to the row of spine articulations; large, poorly defined, proximalwards protruding and slightly prominent spur on the outer proximal edge; up to seven dorso-ventrally compressed spine articulations composed of massive dorsal and ventral ridges fully separated at their proximal tips; inner side of lateral arm plates with vertebral articular structures composed of a well-defined prominent triangular central knob and a similarly well-defined oblique, slightly arched proximal ridge with a ventralward-pointing dorsal tip. Locus typicus. Punta Mazza, Capo Milazzo, NE Sicily, Italy (38.270694�� N, 15.239373�� E). Stratum typicum. Yellowish marls of the MPL5���MPL6, Piacenzian to Gelasian, latest Pliocene to earliest Pleistocene, approximately 2.6 mya. Description of the holotype. MnhnL OPH074 (Fig. 2 A���B) is a dissociated proximal to median lateral arm plate approximately 1.3 times longer than high with deeply concave dorsal edge as a result of an extreme constriction; ventral edge weakly convex; outer proximal edge convex, with a large, smooth, protruding, slightly prominent and poorly defined spur proximally fading into the crest of the outer surface curvature; outer surface with moderately coarsely meshed stereom with very weak vertical striation in a narrow line along the proximal edge of a welldefined, slightly wavy ridge bordering the row of spine articulations; outer surface stereom slightly more densely meshed on crest of curvature in distal continuation of the spur on the outer proximal edge; seven spine articulations on strongly bulging distal portion of lateral arm plate, forming a row from the ventral to the dorsal edge of the lateral arm plate and probably forming a continuous to near-continuous fan of arm spines in the intact individual; size of spine articulations and of gaps separating them increasing towards the dorsal edge of the lateral arm plate; spine articulations dorso-ventrally compressed, consisting of a large, comma-shaped, near-horizontal dorsal lobe composed of compact stereom and a much shorter, straight, horizontal ventral lobe composed of compact to weakly perforate stereom; dorsal and ventral lobes proximally and distally completely separate, with weak sigmoidal fold distally; spine articulations distally bordered by brink composed of slightly more finely meshed stereom than on outer surface, with brink starting at second ventralmost spine articulation, widest at second dorsalmost spine articulation. Inner side of lateral arm plate (Fig. 2B) with thick ventral edge showing a large contact surface with opposite lateral arm plate suggesting small ventral arm plates widely separated by lateral arm plates; dorsal edge much thinner but also showing extensive contact surface with opposite lateral arm plate, suggesting small dorsal arm plates restricted to the distal quarter of the arm segment; vertebral articular structures consisting of a well-defined, prominent central knob composed of slightly more finely meshed stereom than remaining inner side of lateral arm plate, proximally bordered and seemingly merged with a much smaller but similarly prominent and well-defined knob; additional vertebral articular structure consisting of a similarly well-defined, boomerang-shaped proximal ridge; weakly developed, narrow vertical ridge in distal third of the lateral arm plate, distally bordered by a very weak vertical furrow without clearly discernible perforations; inner distal edge with a large but poorly defined area of compact to very dense stereom corresponding to spur on outer proximal edge; tentacle notch small and inconspicuous. Paratype supplements. MnhnL OPH075 (Fig. 2 C���D) is a dissociated proximal to proximalmost lateral arm plate slightly higher than long; dorso-proximal tip missing, otherwise well preserved, with respect to finer stereom structures even better preserved than holotype specimen; outer proximal edge and outer surface ornamentation as in holotype; seven spine articulations as in holotype except for enlarged and distalwards displaced dorsalmost spine articulation. Inner side with vertebral articular structures as in holotype except for more clearly separated large and small central knobs. MnhnL OPH076 (Fig. 2 E���F) is a dissociated distal lateral arm plate approximately 1.5 times longer than high; general plate outline, outer surface ornamentation and outer proximal edge as in holotype but with weaker constriction and thus less strongly concave dorsal edge; dorso-proximal tip of lateral arm plate missing; six spine articulations as in holotype; size of gaps separating spine articulations increasing dorsalwards but size of spine articulations unchanging. Inner side as in holotype but with widely separated large and small central knobs; proximal vertebral articular structure roughly boomerang shaped but very poorly defined., Published as part of Numberger-Thuy, Lea D. & Thuy, Ben, 2020, A new bathyal ophiacanthid brittle star (Ophiuroidea: Ophiacanthidae) with Caribbean affinities from the Plio-Pleistocene of the Mediterranean, pp. 19-30 in Zootaxa 4820 (1) on pages 22-24, DOI: 10.11646/zootaxa.4820.1.2, http://zenodo.org/record/4397238

Ophiacantha smitti Ljungman, 1872 Reports for the Azores: Ophiacantha smitti Ljungman, 1872 — $ St̂hr & Segonzac 2005: 286. Type locality: Portugal (38°10’N, 9°25’W). See: Ljungman (1872: 621–622); Paterson (1985: 46–47, fig. 20). Occurrence: North Atlantic, from the Bay of Biscay south to off Western Sahara (Paterson 1985, Bartsch 1987), including the Azores (St̂hr & Segonzac 2005) and Madeira (Jesus & Abreu 1998); also off Bermuda (Lyman 1882). Depth: 75– 2,282 m (Jesus & Abreu 1998, Paterson 1985); AZO: 1,550 m (St̂hr & Segonzac 2005). Habitat: soft bottoms, muddy sand (Jesus & Fonseca 1999) to grey ooze (Lyman 1882). Remarks: Ophiacantha smitti, a species known from both sides of the Atlantic, is one of the more recent additions to the deep-water echinoderm fauna from the Azores, identify by St̂hr & Segonzac (2005) in a non-vent area near Lucky Strike (L’Atalante, Victor 1ère cruise, sta PL 33: 37°15’45”N, 32°13’30”W, 1,550 m)., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on pages 36-37, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Ljungman, A. V. (1872) F ˆ rteckning ˆ fver uti Vestindien af Dr A. Goes samt under korvetten Josefinas expedition i Atlantiska Oceanen samlade Ophiurider. Ofversigt af Kongliga Vetenskaps-Akademiens F ˆ rhandlingar, 28 (5), 615 - 658. [1871]","St ˆ hr, S. & Segonzac, M. (2005) Deep-sea ophiuroids (Echinodermata) from reducing and non-reducing environments in the North Atlantic Ocean. Journal of the Marine Biological Association of the United Kingdom, 85 (2), 383 - 402. https: // doi. org / 10.1017 / S 0025315405011318 h","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162.","Bartsch, I. (1987) Notes on Ophiuroidea (Echinodermata) from the northeastern Atlantic Ocean. I. Ophiacanthidae. Spixiana, 10, 115 - 130.","Jesus, D. & Abreu, A. D. (1998) Contribution to the knowledge of the soft bottom echinoderms of Madeira Island. Boletim do Museu Municipal do Funchal (Historia Natural), 50 (286), 59 - 69., 4 figs.","Lyman, T. (1882) Report on the Ophiuroidea. Report on the Scientific Results of the Voyage of H. M. S. Challenger 1873 - 1876, Zoology, 5 (14), 1 - 386.","Jesus, D. C. & Fonseca, L. C. (1999) First records of 13 echinoderm species on the southwest coast of Portugal. Boletin Instituto Espanol de Oceanografia, 15 (1 - 4), 343 - 349."]}

Ophiacantha simulans Koehler, 1895c Reports for the Azores: non Ophiacantha composita Koehler, 1897 a— $ Koehler 1909: 185 [misidentification]; García-Diez et al. 2005: 49 [based on Koehler 1909]; Ophiacantha simulans Koehler, 1895 c—Gage et al. 1983: 291; Paterson 1985: 39–40, fig. 17; Martynov & Litvinova 2008: 96, fig. 11B; Smirnov et al. 2014: 196. Type locality: Bay of Biscay. See: Koehler (1895c: 465–467; fig. 7; 1896c: 82–84); Mortensen (1933a: 26–29, figs. 11, 12, pl. 3, figs. 5–6); Paterson (1985). Occurrence: North Atlantic, from off North Carolina eastwards to Iceland in the North (Gage et al. 1983), southwards to off Morocco (Bartsch 1987) including the archipelagos of the Azores and Canaries (Koehler 1909). Depth: 1,480–3,018 m (Mortensen 1933a); AZO: 1,919–3,018 m (Koehler 1909). Habitat: soft substrates, mud to muddy sand and corals (Koehler 1909). Remarks: Koehler (1906b, 1909) reported small animals collected by the Talisman, Travailleur and Princesse Alice in the Bay of Biscay, Canaries and the Azores, which he believed to be Ophiacantha composita, a species he described for the Indian Ocean. Mortensen (1933a) disagreed with Koehler stating that the NE Atlantic animals were O. simulans. Paterson (1985) re-examined the material from the Talisman and Travailleur collected in the Bay of Biscay and agreed with Mortensen, assigning Koehler’s Ophiacantha composita specimens from the Atlantic to O. simulans., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 36, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Koehler, R. (1895 c) Dragages profonds executes a bord du Caudan dans le Golfe de Gascogne. Rapport preliminaire sur le Echinodermes. Revue biologique du Nord de la France, 7, 439 - 496.","Koehler, R. (1897 a) Echinodermes recueillis par \" l'Investigator \" dans l'Ocean Indien. I. Les Ophiures de mer profonde. Annales Sciences Naturelles Zoologie et Paleontologie, 4, 273 - 372.","Koehler, R. (1909) Echinodermes provenant des campagnes du yacht Princesse-Alice (Asteries, Ophiures, Echinides et Crinoides). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 34, 1 - 317.","Garcia-Diez, C., Porteiro, F. M., Meirinho, A., Cardigos, F. & Tempera, F. (2005) Taxonomic review of selected invertebrate groups collected during the Campaigns of the Prince Albert I of Monaco in the Azorean waters. Arquipelago. Life and Marine Sciences, 22 A, 35 - 59.","Koehler, R. (1895 a) Note preliminaire sur les echinides recueillis pendant les campagnes de l'Hirondelle. Bulletin de la Societe Zoologique de France, 20, 223 - 227.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162.","Martynov, A. V. & Litvinova, N. M. (2008) Deep-water Ophiuroidea of the northern Atlantic with descriptions of three new species and taxonomic remarks on certain genera and species. Marine Biology Research, 4, 76 - 11. https: // doi. org / 10.1080 / 17451000701840066","Smirnov, I. S., Piepenburg, D., Ahearn, C. & Juterzenka, K. V. (2014) Deep-sea fauna of European seas: An annotated species check-list of benthic invertebrates living deeper than 2000 m in the seas bordering Europe. Ophiuroidea. Invertebrate Zoology, 11 (1), 192 - 209. https: // doi. org / 10.15298 / invertzool. 11.1.18","Mortensen, T. (1933 a) Ophiuroidea. The Danish Ingolf Expedition, 4 b (8), 1 - 121.","Gage, J. D., Billett, D. S. M., Jensen, M. & Tyler, P. A. (1983) Echinoderms of the Rockall Trough and adjacent areas. I. Crinoidea, Asteroidea and Ophiuroidea. Bulletin of the British Museum (Natural History), Zoology, 45, 263 - 308. https: // doi. org / 10.5962 / bhl. part. 28002","Bartsch, I. (1987) Notes on Ophiuroidea (Echinodermata) from the northeastern Atlantic Ocean. I. Ophiacanthidae. Spixiana, 10, 115 - 130.","Koehler, R. (1906 b) Ophiures. Expeditions Scientifiques du Travailleur et du Talisman, 8, 245 - 311."]}

Ophiacantha bidentata ? (Bruzelius, 1805) Reports for the Azores: Ophiacantha bidentata (Bruzelius, 1805) —? $ Koehler 1898: 55; Koehler 1924: 244–246; Mortensen 1927a: 196, figs. 105.1–2; Nobre 1938: 72; Paterson 1985: 34–36, fig. 15; García-Diez et al. 2005: 49; Micael & Costa 2010: 322; Benavides-Serrato et al. 2011: 244–245; Micael et al. 2012: 3; Smirnov et al. 2014: 195. Type locality: Norway. See: Bruzelius (1805: 33, as Asterias bidentata); Mortensen (1933a: 20–22, figs. 6–8); Martynov & Litvinova (2008). Occurrence: Arctic (circumpolar) and North Atlantic, from the eastern coast of USA to Greenland and in the eastern Atlantic from South of Iceland to Cape Blanc (Paterson 1985), including the archipelagos of the?Azores (Koehler 1898), Madeira (Jesus & Abreu 1998), Canaries (Koehler 1906b) and? Cape Verde (Mortensen 1927a). Depth: 10–? 4,730 m (Smirnov et al. 2014);? AZO:? 1,287 m (Koehler 1898). Remarks: when describing Ophiacantha fraterna, Verrill (1885c) cautioned that this species had previously been confused with O. bidentata, including some of the H.M.S. Challenger material identified by Lyman (1882). Verrill (1885b) also added that O. bidentata unlike O. fraterna occurs at moderate depths. Later authors consider O. fraterna as a junior synonym of O. bidentata, or a variety of the latter (e.g., Mortensen 1933a; Paterson 1985). As a result, it is difficult to understand the true geographical and depth range of O. bidentata (see discussion by Martynov & Litvinova 2008). In view of this and considering that the report of Ophiacantha bidentata in the archipelago is based on a single poorly preserved specimen collected at a depth of 1,287 m (Koehler 1898; Hirondelle, sta 112: 38°48’30”N, 28°06’16”W), the inclusion of this species in the Azorean faunal list should be considered with caution. Mortensen (1927a) included Cape Verde in the geographical distribution of O. bidentata. To the best of our knowledge no animal belonging to this species was ever collected in the archipelago. In an earlier report, Koehler (1906b) recorded this species at Talisman deep-water stations located between off NW African coast and Canaries. It is possible that Mortensen (1927a) mistook Koehler’s records, which was repeated by subsequent references (e.g., Mortensen 1933 a, Nobre 1938, Madsen 1947)., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 34, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Bruzelius, N. (1805) Dissertatio sistens species cognitas asteriarum, quam, sub praesidio A. J. Retzii. exhibet N. Bruzelius. Berlingianis, Lundae, 37 pp.","Koehler, R. (1898) Echinides et Ophiures provenant des campagnes du yacht Hirondelle (Golfe de Gascogne, Acores, Terre- Neuve). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 12, 1 - 78.","Koehler, R. (1924) Les echinodermes des mers d'Europe. Encyclopedie Scientifique. Tome I. Libraire Octave Doin, Paris, XIII + 361 pp.","Mortensen, T. (1927 a) Handbook of the echinoderms of the British Isles. Oxford University Press, viii + 471 pp. https: // doi. org / 10.5962 / bhl. title. 6841","Nobre, A. (1938) Equinodermes de Portugal. 3 rd Edition. Companhia Editora do Minho, Barcelos, 215 pp.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162.","Garcia-Diez, C., Porteiro, F. M., Meirinho, A., Cardigos, F. & Tempera, F. (2005) Taxonomic review of selected invertebrate groups collected during the Campaigns of the Prince Albert I of Monaco in the Azorean waters. Arquipelago. Life and Marine Sciences, 22 A, 35 - 59.","Micael, J. & Costa A. C. (2010) Echinodermata. In: Borges, P. A. V., Costa, A., Cunha, R., Gabriel, R., Goncalves, V., Martins, A. F., Melo, I., Parente, M., Raposeiro, P., Rodrigues, P., Santos, R. S., Silva, L., Vieira, P. & Vieira, V. (Eds.), A list of the terrestrial and marine biota from the Azores. Principia, Oeiras, pp. 321 - 323.","Benavides-Serrato, M., Borrero-Perez, G. H. & Diaz-Sanchez, C. M. (2011) Equinodermos del Caribe colombiano I: Crinoidea, Asteroidea y Ophiuoridea. Vol. 22. Serie de Publicaciones Especiales de Invemar, Santa Marta, 384 pp.","Micael, J., Alves, M. J., Jones, M. B. & Costa, A. C. (2012) Diversity of shallow-water asteroids (Echinodermata) in the Azorean Archipelago. Marine Biodiversity Records, 5, e 49. https: // doi. org / 10.1017 / S 1755267211000534","Smirnov, I. S., Piepenburg, D., Ahearn, C. & Juterzenka, K. V. (2014) Deep-sea fauna of European seas: An annotated species check-list of benthic invertebrates living deeper than 2000 m in the seas bordering Europe. Ophiuroidea. Invertebrate Zoology, 11 (1), 192 - 209. https: // doi. org / 10.15298 / invertzool. 11.1.18","Mortensen, T. (1933 a) Ophiuroidea. The Danish Ingolf Expedition, 4 b (8), 1 - 121.","Martynov, A. V. & Litvinova, N. M. (2008) Deep-water Ophiuroidea of the northern Atlantic with descriptions of three new species and taxonomic remarks on certain genera and species. Marine Biology Research, 4, 76 - 11. https: // doi. org / 10.1080 / 17451000701840066","Jesus, D. & Abreu, A. D. (1998) Contribution to the knowledge of the soft bottom echinoderms of Madeira Island. Boletim do Museu Municipal do Funchal (Historia Natural), 50 (286), 59 - 69., 4 figs.","Koehler, R. (1906 b) Ophiures. Expeditions Scientifiques du Travailleur et du Talisman, 8, 245 - 311.","Verrill, A. E. (1885 c) Results of the explorations made by the steamer \" Albatross \", off the northern coast of the United States, in 1883. Report of Commissioner of Fish and Fisheries, 1885 503 - 699. https: // doi. org / 10.5962 / bhl. title. 12059","Lyman, T. (1882) Report on the Ophiuroidea. Report on the Scientific Results of the Voyage of H. M. S. Challenger 1873 - 1876, Zoology, 5 (14), 1 - 386.","Verrill, A. E. (1885 b) Notice of recent additions to the marine invertebrata of the northeastern coast of America, with descriptions of new genera and species and critical remarks on others. Part V-Annelida, Echinodermata, Hydroida, Tunicata. Proceedings of the United States National Museum, 8, 424 - 447. https: // doi. org / 10.5479 / si. 00963801.534.424","Madsen, F. J. (1947) The Echinoderms collected by the \" Skagerak \" Expedition in the Eastern Atlantic 1946. Meddelanden fran G ˆ teborgs Kungliga Vetenskaps- och Vitterhets- Samhalles Handlingar, sjatte f ˆ ljden, Serie B, 5 (7), 1 - 16."]}

Ophiacantha aristata Koehler, 1895c Reports for the Azores: Ophiacantha aristata Koehler, 1895 c— $ Koehler 1896a: 212, 1898: 55, 1906b: 288–289, 1909: 183, pl. 26, figs. 5–6, 1921a: 2; Mortensen 1927a: 191, 193–194, fig. 107; Grieg 1932: 38; Nobre 1938: 76–77; García-Diez et al. 2005: 49. Type locality: Bay of Biscay. See: Koehler (1896c: 81–86, figs. 43, 44); Rodrigues et al. (2011: 7, fig. 2). Occurrence: Northeast Atlantic, from the Reykjanes Ridge (S of Iceland; Copley et al. 1996) and British Isles to NW Africa (Paterson 1985), including the Azores and Canaries (Koehler 1909). Depth: 658– 1,805 m (Copley et al. 1996); AZO: 1,095 –1,740 m (Koehler 1909, 1921a). Habitat: soft bottoms, mud to sand (Koehler 1909) and on corals (Rodrigues et al. 2011). Remarks: Koehler (1896a, 1898, 1906b, 1909, 1921a) recorded Ophiacantha aristata among the material collected by the main oceanographic cruises crossing the Azorean archipelago waters at the time (Hirondelle, Talisman, Princesse Alice). This species is only known in the archipelago from Koehler’s historical reports., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 33, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Koehler, R. (1895 c) Dragages profonds executes a bord du Caudan dans le Golfe de Gascogne. Rapport preliminaire sur le Echinodermes. Revue biologique du Nord de la France, 7, 439 - 496.","Koehler, R. (1895 a) Note preliminaire sur les echinides recueillis pendant les campagnes de l'Hirondelle. Bulletin de la Societe Zoologique de France, 20, 223 - 227.","Koehler, R. (1896 a) Note preliminaire sur les Ophiures recueillies pendant les campagnes de \" L'Hirondelle \". Memoires. Societe Zoologique de France, 9, 203 - 213.","Koehler, R. (1898) Echinides et Ophiures provenant des campagnes du yacht Hirondelle (Golfe de Gascogne, Acores, Terre- Neuve). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 12, 1 - 78.","Koehler, R. (1906 b) Ophiures. Expeditions Scientifiques du Travailleur et du Talisman, 8, 245 - 311.","Koehler, R. (1909) Echinodermes provenant des campagnes du yacht Princesse-Alice (Asteries, Ophiures, Echinides et Crinoides). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 34, 1 - 317.","Mortensen, T. (1927 a) Handbook of the echinoderms of the British Isles. Oxford University Press, viii + 471 pp. https: // doi. org / 10.5962 / bhl. title. 6841","Grieg, J. A. (1932) Echinodermata. Report of the scientific results of the Michael Sars North Atlantic deep sea expedition 1910, 3 (2), 1 - 47.","Nobre, A. (1938) Equinodermes de Portugal. 3 rd Edition. Companhia Editora do Minho, Barcelos, 215 pp.","Garcia-Diez, C., Porteiro, F. M., Meirinho, A., Cardigos, F. & Tempera, F. (2005) Taxonomic review of selected invertebrate groups collected during the Campaigns of the Prince Albert I of Monaco in the Azorean waters. Arquipelago. Life and Marine Sciences, 22 A, 35 - 59.","Koehler, R. (1896 c) Echinodermes. Resultats scientifiques de la Campagne du \" Caudan \" dans le Golfe de Gascogne. Annales de l'Universite de Lyon, 26, 33 - 127. https: // doi. org / 10.5962 / bhl. title. 65730","Rodrigues, C. F., Paterson, G. Cabrinovic, A. & Cunha, M. R. (2011) Deep-sea ophiuroids (Echinodermata: Ophiuroidea: Ophiurida) from the Gulf of Cadiz (NE Atlantic). Zootaxa, 2754, 1 - 26. https: // doi. org / 10.11646 / zootaxa. 2754.1.1","Copley J. T. P., Tyler, P. A., Sheader, M., Murton, B. J. & German, C. R. (1996) Megafauna from sublittoral to abyssal depths along the Mid-Atlantic Ridge south of Iceland. Oceanologica Acta, 19 (5), 549 - 559.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162.","Koehler, R. (1921 a) Echinodermes (Asteries, Ophiures, Echinides et Crinoides) des dernieres campagnes de la Princesse-Alice et de l' Hirondelle II. Bulletin de l'Institut Oceanographique de Monaco, 396, 1 - 8."]}

Ophiacantha abyssicola Sars, 1872 Reports for the Azores: Ophiacantha abyssicola Sars, 1872 — $ Koehler 1909: 182; Farran 1913: 38–39, fig. 9d; Mortensen 1927a: 194, figs. 105.5–6; Grieg 1932: 37; García-Diez et al. 2005: 49. Type locality: Norway. See: Sars (1872: 8–10); Paterson (1985: 47–48, fig. 20). Occurrence: North Atlantic, Northeast American coast, north of Cape Hatteras to Greenland and Iceland, eastwards to Scandinavia, southwards to the Western Sahara (Paterson (1985), including the Azores (Koehler 1909), Madeira (Jesus & Abreu (1998), Canaries (Madsen 1970), and the Atlantis Seamount (A.H. Clark 1949). Depth: 35– 3,500 m (Mortensen (1927a), an upper bathyal species that may occur in shallow waters at higher latitudes, such as the Norwegian Sea (Gage et al. 1983); AZO: 880 m (Koehler 1909). Habitat: rock, coral, mud to gravel and detritic substrates (Farran 1913; Cherbonnier 1969, 1970); it can form dense beds (Metaxas & Giffin 2004). Remarks: the record of Ophiacantha abyssicola in the Azores is based on a single small specimen collected by Princesse Alice (sta 837: 37°55’N, 25°24’15”W, 880 m) and identified by Koehler (1909)., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on pages 32-33, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Sars, G. O. (1872) Nye Echinodermer fra den norske kyst. Videnskabelige Selskabets Forhandlinger, 1871, 1 - 31.","Koehler, R. (1909) Echinodermes provenant des campagnes du yacht Princesse-Alice (Asteries, Ophiures, Echinides et Crinoides). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 34, 1 - 317.","Farran, G. P. (1913) The deep-water Asteroidea, Ophiuroidea and Echinoidea of the West Coast of Ireland. Department of Agriculture and technical instruction for Ireland, fisheries branch, scientific investigations, 6, 1 - 66. [1912]","Mortensen, T. (1927 a) Handbook of the echinoderms of the British Isles. Oxford University Press, viii + 471 pp. https: // doi. org / 10.5962 / bhl. title. 6841","Grieg, J. A. (1932) Echinodermata. Report of the scientific results of the Michael Sars North Atlantic deep sea expedition 1910, 3 (2), 1 - 47.","Garcia-Diez, C., Porteiro, F. M., Meirinho, A., Cardigos, F. & Tempera, F. (2005) Taxonomic review of selected invertebrate groups collected during the Campaigns of the Prince Albert I of Monaco in the Azorean waters. Arquipelago. Life and Marine Sciences, 22 A, 35 - 59.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162.","Jesus, D. & Abreu, A. D. (1998) Contribution to the knowledge of the soft bottom echinoderms of Madeira Island. Boletim do Museu Municipal do Funchal (Historia Natural), 50 (286), 59 - 69., 4 figs.","Madsen, F. J. (1970) West African Ophiuroids. Atlantidae Report, 11, 151 - 243.","Clark, A. H. (1949) Echinoderms from the mid-Atlantic dredged by lhe Atlantis in the summer of 1948. Journal of the Washington Academy of Sciences, 39, 371 - 377.","Gage, J. D., Billett, D. S. M., Jensen, M. & Tyler, P. A. (1983) Echinoderms of the Rockall Trough and adjacent areas. I. Crinoidea, Asteroidea and Ophiuroidea. Bulletin of the British Museum (Natural History), Zoology, 45, 263 - 308. https: // doi. org / 10.5962 / bhl. part. 28002","Cherbonnier, G. (1969) Echinodermes recoltes par la \" Thalassa \" au large de cotes d'espagne et du Golfe de Gascogne (3 - 12 AOUT 1967). Bulletin Museum National Histoire Naturelle Paris, Serie 2, 41 (1), 343 - 361.","Cherbonnier, G. (1970) Echinodermes recoltes par la \" Thalassa \" au large de cotes d'espagne et du Golfe de Gascogne (18 - 25 AOUT 1968). Bulletin Museum National Histoire Naturelle, Paris, 2 ª Serie, 41 (5), 1266 - 1277.","Metaxas, A. & Giffin, B. (2004) Dense beds of the ophiuroid Ophiacantha abyssicola on the continental slope off Nova Scotia, Canada. Deep-Sea Research I, 51, 1307 - 1317. https: // doi. org / 10.1016 / j. dsr. 2004.06.001"]}

Erroneous— Ophiacantha brevispina Koehler, 1898 Reports for the Azores: Ophiacantha brevispina Koehler, 1898 — Bartsch 1987: 120–121, figs. 16, 17. Type locality: Bay of Biscay (46°27’00″N, 4°09’46″W). See: Koehler (1898: 56–57, pl. 8, figs. 43, pl. 9, fig. 44). Occurrence: Northeast Atlantic, from the Bay of Biscay to Dakar in Senegal (Koehler 1898, Bartsch 1987), including Madeira (Jesus & Abreu 1998). Depth: 90–417 m (Bartsch 1987). Habitat: soft sediment, sand to muddy sand (Cadenat 1938). Remarks: few specimens of Ophiacantha brevispina have been found since Koehler (1898) described this species. Cadenat (1938) identified numerous animals from an area that the author referred as Cape Blanc and Cape Verde as Ophiacantha sp., though none of the specimens came from the later archipelago but from Dakar. Regardless Cadenat remarked that these brittle stars were quite close to what Koehler described as Ophiacantha brevispina. Later, Bartsch (1987) recorded O. brevispina from the same region as the previous author. Bartsch erroneously listed the Azores under geographical range of this species (citing Cadenat 1938), mistaking the Cape Verde Islands with the Azores., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 163, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Koehler, R. (1898) Echinides et Ophiures provenant des campagnes du yacht Hirondelle (Golfe de Gascogne, Acores, Terre- Neuve). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 12, 1 - 78.","Bartsch, I. (1987) Notes on Ophiuroidea (Echinodermata) from the northeastern Atlantic Ocean. I. Ophiacanthidae. Spixiana, 10, 115 - 130.","Jesus, D. & Abreu, A. D. (1998) Contribution to the knowledge of the soft bottom echinoderms of Madeira Island. Boletim do Museu Municipal do Funchal (Historia Natural), 50 (286), 59 - 69., 4 figs.","Cadenat, J. (1938) Liste des echinodermes recueillis pendant la cinquieme croisiere du navire de recherches President-Theodore- Tissier. Revue des Travaux de l'Institut des Peches Maritimes, 11, 349 - 375."]}

Erroneous— Ophiomitrella clavigera (Ljungman, 1865) Reports for the Azores: non Ophiomitrella clavigera (Ljungman, 1864) — Mortensen 1927a: 186–187, fig. 103 [based on invalid synonymy]; Marques 1980: 102 [based on Mortensen 1927a]; Paterson 1985: 71, fig. 28 [based on Mortensen 1927a]; Harvey et al. 1988: 170 [based on Paterson 1985]; García-Diez et al. 2005: 49 [based on Mortensen 1927a]. Type locality: Norway. See: Mortensen (1933a: 39–41, fig. 23); Paterson (1985). Occurrence: North Atlantic, in the west from the Northern American coasts to Greenland and in the east from Iceland and Scandinavia to the British waters (Mortensen 1933 a, Paterson 1985). Depth: 166– 1,952 m (Paterson 1985, Harvey et al. 1988). Habitat: coral epibiont and also known from muddy sand (Farran 1913). Larval stage: brooding, protandric hermaphrodite (Mortensen 1920). Remarks: Ophiomitrella clavigera was included in the Azorean fauna based on the erroneous assumption that O. cordifera was conspecific with this species (for details see remarks under Ophiomitrella cordifera)., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 164, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Ljungman, A. V. (1865) Tillagg till kannedom af Skandinaviens Ophiurider. Ofversigt af Kongliga Vetenskaps-Akademiens F ˆ rhandlingar, 21 (7), 359 - 367. [1863]","Mortensen, T. (1927 a) Handbook of the echinoderms of the British Isles. Oxford University Press, viii + 471 pp. https: // doi. org / 10.5962 / bhl. title. 6841","Marques, V. M. (1980) Echinodermes recueillis pedant la mission \" Hesperides 76 \" du N / O Jean Charcot. Arquivo do Museu Bocage, 2 ª Serie, 7 (7), 95 - 107.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162.","Harvey, R., Gage, J. D., Billett, D. S. M., Clark, A. M. & Paterson, G. L. J. (1988) Echinoderms of the Rockall Trough and adjacent areas. 3. Additional records. Bulletin British Museum Natural History, Zoology, 54, 153 - 198.","Garcia-Diez, C., Porteiro, F. M., Meirinho, A., Cardigos, F. & Tempera, F. (2005) Taxonomic review of selected invertebrate groups collected during the Campaigns of the Prince Albert I of Monaco in the Azorean waters. Arquipelago. Life and Marine Sciences, 22 A, 35 - 59.","Mortensen, T. (1933 a) Ophiuroidea. The Danish Ingolf Expedition, 4 b (8), 1 - 121.","Farran, G. P. (1913) The deep-water Asteroidea, Ophiuroidea and Echinoidea of the West Coast of Ireland. Department of Agriculture and technical instruction for Ireland, fisheries branch, scientific investigations, 6, 1 - 66. [1912]","Mortensen, T. (1920) Notes on some Scandinavian Echinoderms with descriptions of two new Ophiuroids. Videnskabelige Meddelser fra Dansk Naturhistorisk Forening i KjObenhavn, 72, 45 - 79."]}

Ophiacantha setosa (Bruzelius, 1805) Reports for the Azores: Ophiacantha setosa M̹ller & Troschel, 1842 —? Koehler 1898: 57–58, pl. 8, figs. 37–38; $ Nobre 1938: 74, fig. 34.2; Ophiacantha setosa (Bruzelius, 1805) — $ Koehler 1906b: 291–292; Tortonese 1965: 218–220, fig. 102. See: Tortonese (1965); Paterson (1985: 37–38, fig. 16). Occurrence: Mediterranean Sea and East Atlantic, from the Bay of Biscay along West African coast as far as Angola (Paterson 1985), including the archipelagos of the Azores (Koehler 1906b), Canaries (Bacallado et al. 1985) and Cape Verde (Rochebrune 1881). Depth: 5– 1,480 m (Koukouras et al. 2007); AZO:?139– 1,257 m (Koehler 1898, 1906b). Habitat: abundant in detritic substrates and a frequent epibiont on gorgonians (Tortonese 1965). Remarks: the first report of Ophiacantha setosa from the Azores can be traced back to Koehler (1898). In the introduction and later in the discussion of the geographical distribution of this species (pages 32 and 58), Koehler remarked that he found this species in the Azores at a depth of 139 m, without giving any further details. However, Koehler (pp. 33, 57, 69) only listed a station sampled by Hirondelle located in the Bay of Biscay, at a depth of 135 m. Regardless, the same author (1906b) later identified a specimen belonging to O. setosa among the material collected by Talisman in the Azores (sta 127, 1883: 38°38’N, 28°20’46”W, 1,257 m), which appears to have been re-examined later by Nobre (1938)., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 36, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Bruzelius, N. (1805) Dissertatio sistens species cognitas asteriarum, quam, sub praesidio A. J. Retzii. exhibet N. Bruzelius. Berlingianis, Lundae, 37 pp.","M ʾ ller, J. & Troschel, F. H. (1842) System der Asteriden. Vieweg und Sohn, Braunschweig, xxx + 134 pp.","Koehler, R. (1898) Echinides et Ophiures provenant des campagnes du yacht Hirondelle (Golfe de Gascogne, Acores, Terre- Neuve). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 12, 1 - 78.","Nobre, A. (1938) Equinodermes de Portugal. 3 rd Edition. Companhia Editora do Minho, Barcelos, 215 pp.","Koehler, R. (1906 b) Ophiures. Expeditions Scientifiques du Travailleur et du Talisman, 8, 245 - 311.","Tortonese, E. (1965) Fauna D'Italia-Echinodermata. Edizioni Calderini, Bologna, 422 pp.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162.","Bacallado, J. J., Moreno, E. & Perez-Ruzafa, A. (1985) Echinodermata (Canary Islands) provisional Check-list. In: Keegan, B. F. & O'Connor, B. D. S. (Eds.), Echinodermata; Proceedings of the 5 th International Echinoderm Conference, Galway, September 1984. A. A. Balkema, Rotterdam, pp. 149 - 151.","Rochebrune, A. T. (1881) Materiaux pour la faune de l'Archipel du Cap Vert. Nouvelle Archives du Museum National d'Histoire Naturelle, Paris, Series 2, 4, 215 - 340.","Koukouras, A., Sinis, A. I., Bobori, D., Kazantzidis, S. & Kitsos, M. - S. (2007) The echinoderm (Deuterostomia) fauna of the Aegean Sea, and comparison with those of the neighbouring seas. Journal of Biological Research, 7, 67 - 92."]}

Ophiacantha notata Koehler, 1906a Reports for the Azores: Ophiacantha notata Koehler, 1906 a— $ St̂hr & Segonzac 2005: 386. Type locality: Bay of Biscay (45°05’00”N, 7°00’26”W). See: Koehler (1906a: 23–24, pl. 2, figs. 28–30; 1906b: 284–286. pl. 20, figs. 36–38); Paterson (1985: 44, fig. 19). Occurrence: only known from the Bay of Biscay (Koehler 1906a) and near Menez Gwen, in Azores (St̂hr & Segonzac 2005). Depth: 850– 1,226 m (AZO: 850 m; Koehler 1906 a, St̂hr & Segonzac 2005). Remarks: until recently, Ophiacantha notata was known only from the type material collected by Travailleur and Talisman expeditions in the Bay of Biscay. St̂hr & Segonzac reported this rare species from the waters in the vicinity of Menez Gwen, in the southwest of the Azores (SEAHMA–1, DR01: 37°50’32”N, 31°31’16”W, 850 m)., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 35, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Koehler, R. (1906 a) Description des ophiures nouvelles recueillies par le Travailleur et le Talisman. Memoires de la Societe Zoologique de France, 19, 5 - 34.","St ˆ hr, S. & Segonzac, M. (2005) Deep-sea ophiuroids (Echinodermata) from reducing and non-reducing environments in the North Atlantic Ocean. Journal of the Marine Biological Association of the United Kingdom, 85 (2), 383 - 402. https: // doi. org / 10.1017 / S 0025315405011318 h","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162."]}

Ophiacantha aculeata Verrill, 1885a Reports for the Azores: Ophiacantha aculeata Verrill, 1885 — $ Martynov & Litvinova 2008: 90–91, figs. 7A, 10. Type locality: off Virginia, USA (37°50’00”N, 73°03’50”W). See: Verrill (1885a: 153; 1885b: 443–444); Koehler (1914a: 74–77, pl. 11, figs. 1–2); Martynov & Litvinova (2008). Occurrence: North Atlantic deep waters, from off Virginia to New England, eastwards to Rockall Trough, the Bay of Biscay to Iberian Basin, including in the Mid-Atlantic Ridge, from Reykjanes Ridge to the north of the Azores (Martynov & Litvinova 2008). Depth: 1,650–3,584 m (AZO: 2,954–2,968 m; Martynov & Litvinova 2008). Habitat: soft sediments (Globigerina ooze; Verrill 1885a). Remarks: Ophiacantha aculeata was recently identified by Martynov & Litvinova (2008) among the material collected by G.O. Sars (MAR–ECO expedition) at a station located at the northern border of the Azorean waters (sta 40/367: 42°55’N, 30°20’W, 2,954 –2,968 m). This species has been historically confused with O. fraterna Verrill, 1885c (Martynov & Litvinova 2008), a species also considered at one point conspecific or a variety of O. bidentata (Bruzelius, 1805). See remarks under the latter species., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 33, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Verrill, A. E. (1885 a) Notice of the remarkable Marine Fauna occupying the outer banks off the Southern Coast of New England. The American Journal of Science, Series 3, 29, 149 - 156. https: // doi. org / 10.2475 / ajs. s 3 - 29.170.149","Martynov, A. V. & Litvinova, N. M. (2008) Deep-water Ophiuroidea of the northern Atlantic with descriptions of three new species and taxonomic remarks on certain genera and species. Marine Biology Research, 4, 76 - 11. https: // doi. org / 10.1080 / 17451000701840066","Verrill, A. E. (1885 b) Notice of recent additions to the marine invertebrata of the northeastern coast of America, with descriptions of new genera and species and critical remarks on others. Part V-Annelida, Echinodermata, Hydroida, Tunicata. Proceedings of the United States National Museum, 8, 424 - 447. https: // doi. org / 10.5479 / si. 00963801.534.424","Koehler, R. (1914 a) A Contribution to the Study of Ophiurans of the United States National Museum. Bulletin of the United States National Museum, 84, 1 - 173. https: // doi. org / 10.5479 / si. 03629236.84.1","Verrill, A. E. (1885 c) Results of the explorations made by the steamer \" Albatross \", off the northern coast of the United States, in 1883. Report of Commissioner of Fish and Fisheries, 1885 503 - 699. https: // doi. org / 10.5962 / bhl. title. 12059","Bruzelius, N. (1805) Dissertatio sistens species cognitas asteriarum, quam, sub praesidio A. J. Retzii. exhibet N. Bruzelius. Berlingianis, Lundae, 37 pp."]}

Ophiacantha mesembria H.L. Clark, 1915 Reports for the Azores: Ophiacantha pentagona armata $ Koehler, 1898: 55–56; Ophiacantha mesembria H.L. Clark, 1915 — Koehler 1922: 60–61; Mortensen 1927a: 188. Type locality: off Santa Cruz (Virgin Islands, Caribbean). See: H.L. Clark (1915: 201–202); Benavides-Serrato et al. (2011: 248–249). Occurrence: Northwest Atlantic, known from the Caribbean islands and Gulf of Mexico (Benavides-Serrato et al. 2011) eastwards to the Azores (Koehler 1922) and?Madeira (Jesus & Abreu 1998). Depth: 256– 2,870 m (H.L. Clark 1915, Koeheler 1898); AZO: 2,870 m (Koeheler 1898). Habitat: soft sediments (clayish sand; Koehler 1898). Remarks: Koehler (1898) examined two specimens collected by Hirondelle in Azorean waters, which he placed in a variety armata of O. pentagona, a species described from the Pacific Ocean. Later, Koehler (1922) changed his previous identification of the Hirondelle material, and placed them under the Caribbean O. mesembria, extending its geographical distribution to the Mid-Atlantic and its vertical distribution from 1,143 m to 2,870 m. This species may also occur at Madeira Archipelago (Jesus & Abreu 1998, as Ophiacantha cf. mesembria)., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 35, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Clark, H. L. (1915) Catalogue of recent ophiurans. Memoirs of the Museum of Comparative Zo ˆ logy at Harvard College, 25 (4), 165 - 376.","Koehler, R. (1898) Echinides et Ophiures provenant des campagnes du yacht Hirondelle (Golfe de Gascogne, Acores, Terre- Neuve). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 12, 1 - 78.","Koehler, R. (1922) Ophiurans of the Philippine Seas and adjacent waters. Smithsonian Institution United States National Museum Bulletin, 100 (5), 1 - 486.","Mortensen, T. (1927 a) Handbook of the echinoderms of the British Isles. Oxford University Press, viii + 471 pp. https: // doi. org / 10.5962 / bhl. title. 6841","Benavides-Serrato, M., Borrero-Perez, G. H. & Diaz-Sanchez, C. M. (2011) Equinodermos del Caribe colombiano I: Crinoidea, Asteroidea y Ophiuoridea. Vol. 22. Serie de Publicaciones Especiales de Invemar, Santa Marta, 384 pp.","Jesus, D. & Abreu, A. D. (1998) Contribution to the knowledge of the soft bottom echinoderms of Madeira Island. Boletim do Museu Municipal do Funchal (Historia Natural), 50 (286), 59 - 69., 4 figs."]}

Ophiacantha lineata Koehler, 1896b Reports for the Azores: Ophiacantha lineata $ Koehler, 1896b: 247–249, 1909: 187–188, pl. 25, figs. 6–8, 1921a: 2, 4; Mortensen 1927a: 188; Cherbonnier & Sibuet 1972: 398; $ Paterson 1985: 42–44, fig. 19; García-Diez et al. 2005: 49. Type locality: Azores (38°26’N, 26°30’45”W). See: Koehler (1896b); Bartsch (1987: 122–123, figs. 20–21); Paterson (1985). Occurrence: North Atlantic, from Florida eastwards from Rockall to Western Sahara, including the Azores (Paterson 1985). Depth: 500– 3,175 m (Koehler 1914 a, Cherbonnier & Sibuet 1972); AZO: 1,165 –1,378 m (Koehler 1909, 1921a). Habitat: soft sediments, sand with coral and shells (Koehler 1914a). Remarks: Koehler (1896b, 1909) described Ophiacantha lineata based on specimens collected in the Azores by Princesse Alice (sta 578: 38°26’N, 26°30’45”W, 1,165 m). Koehler (1921a) found further material from the archipelago on a later expedition by Hirondelle II (sta 3140: 37°38’N, 26°01’W, 1,378 m). No other material is known from the archipelago., Published as part of Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), pp. 1-231 in Zootaxa 4639 (1) on page 35, DOI: 10.11646/zootaxa.4639.1, http://zenodo.org/record/3342161, {"references":["Koehler, R. (1896 b) Note preliminaire sur les Ophiures des premieres campagnes de la \" Princesse Alice \". Memoires. Societe Zoologique de France, 9, 241 - 253.","Koehler, R. (1909) Echinodermes provenant des campagnes du yacht Princesse-Alice (Asteries, Ophiures, Echinides et Crinoides). Resultats des campagnes scientifiques accomplies sur son yacht par Albert Ier Prince Souverain de Monaco, 34, 1 - 317.","Mortensen, T. (1927 a) Handbook of the echinoderms of the British Isles. Oxford University Press, viii + 471 pp. https: // doi. org / 10.5962 / bhl. title. 6841","Cherbonnier, G. & Sibuet, M. (1972) Resultats scientifiques de la campagne Noratlante: Asterides et Ophiurides. Bulletin du Museum National D'histoire Naturelle, 102 (76), 1333 - 1394.","Paterson, G. L. J. (1985) The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History), Zoology Series, 49 (1), 1 - 162.","Garcia-Diez, C., Porteiro, F. M., Meirinho, A., Cardigos, F. & Tempera, F. (2005) Taxonomic review of selected invertebrate groups collected during the Campaigns of the Prince Albert I of Monaco in the Azorean waters. Arquipelago. Life and Marine Sciences, 22 A, 35 - 59.","Bartsch, I. (1987) Notes on Ophiuroidea (Echinodermata) from the northeastern Atlantic Ocean. I. Ophiacanthidae. Spixiana, 10, 115 - 130.","Koehler, R. (1914 a) A Contribution to the Study of Ophiurans of the United States National Museum. Bulletin of the United States National Museum, 84, 1 - 173. https: // doi. org / 10.5479 / si. 03629236.84.1","Cherbonnier, G. & Guille, A. (1972) Sur une espece actuelle de Crinoide cretacique de la famille Holopodidae: Cyanthidium foresti nov. sp. Comptes rendus hebdomadaires des seances de l'Academie des sciences. Serie D, Sciences Naturelles, 274, 2193 - 2196.","Koehler, R. (1921 a) Echinodermes (Asteries, Ophiures, Echinides et Crinoides) des dernieres campagnes de la Princesse-Alice et de l' Hirondelle II. Bulletin de l'Institut Oceanographique de Monaco, 396, 1 - 8."]}