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Asteronyx loveni Müller & Troschel, 1842 Figs 2, 3A–B, 4A, D–E Asteronyx loveni Müller & Troschel, 1842: 119, pl. X figs 3–5. Ophiuropsis lymani Studer, 1884: 55, pl. V figs 12a–d. Asteronyx locardi Koehler, 1895: 470–471, fig. 10 Asteronyx loveni – Clark 1923: 314–315. — Mortensen 1927: 158–160, fig. 90 — Paterson, 1985: 13–15, fig. 15. Asteronyx locardi – Koehler 1896: 88–89, pl. 3 fig. 25. Material examined MAURITANIA • 1 spec., 25.22 mm dd; 19°34′14′′– 19°31′34′′ N, 17°31′44′′– 17°30′21′′ W; depth 1689– 1628 m; 23 Nov. 2007; Maurit-1107 exped.; stn MU22; Maurit-1107-04528; LZM-UV • 12 specs, 6.08–21.71 mm dd; 19°25′29″– 19°22′44″ N, 17°33′17″– 17°32′11″ W; depth 1778–1811 m; 26 Nov. 2007; Maurit-1107 exped.; stn MU31; Maurit-1107-05231; LZM-UV • 10 specs, 6.83–19.28 mm dd; 19°55′41″– 19°53′05″ N, 18°01′07″– 18°02′01″ W; depth 1808–1862 m; 21 Nov. 2008; Maurit-0811 exped.;stn MU92; Maurit-0811-03931; LZM-UV • 4 specs, 64.90– 22.98 mm dd; 19°51′02″– 19°49′33″ N, 17°55′33″– 17°53′00″ W; depth 1740–1769 m; 21 Nov. 2008; Maurit-0811 exped.; stn MU93; Maurit-0811-03725; LZM-UV • 2 specs, 9.60–12.56 mm dd; 19°35′15″– 19°32′43″ N, 17°35′13″– 17°33′37″ W; depth 1720–1734 m; 21 Nov. 2008; Maurit-0811 exped.; stn MU94; Maurit-0811-03928; LZM-UV • 1 spec., 11.07 mm dd; 19°59′28″– 19°59′01″ N, 17°57′28″– 17°59′07″ W; depth 1746–1749 m; 22 Nov. 2009; Maurit-0911 exped.; stn MU193; Maurit-0911-03154; LZM-UV • 1 spec., 25.74 mm dd; 16°08′44″– 16°11′14″ N, 17°10′08″– 17°08′40″ W; depth 1595 m; 6 Dec. 2010; Maurit-1011 exped.; stn MU274; Maurit-1011-02982; LZM-UV. WESTERN SAHARA • 1 spec., 11.01 mm dd; 21°33′13″– 21°36′08″ N, 18°07′26″– 18°07′09″ W; depth 1860– 1820 m; 17 Nov. 2006; Maroc-0611 exped.; stn MO198; Maroc-0611-16135; LZM-UV • 1 spec., 5.81 mm dd; 22°59′13″– 22°56′19″ N, 17°37′30″– 17°38′12″ W; depth 1562–1577 m; 26 Nov. 2006; Maroc-0611 exped.; stn MO230; Maroc-0611-16155; LZM-UV. GUINEA BISSAU • 2 specs, 13.24–18.81 mm dd; 10°01′18″– 10°00′24″ N, 17°24′56″– 17°25′05″ W; depth 902–908 m; 29 Oct. 2008; Bissau-0810 exp.; stn BS166; Bissau-0811-06529; LZM-UV. Distribution Asteronyx loveni Müller & Troschel, 1842 is a circumglobal species, widely distributed across the three major oceans (Indian, Pacific and Atlantic). In the Atlantic Ocean, it has been recorded on both sides: in the West Atlantic, from North USA to West Indies (Hernández-Herrejón et al. 2008), and in the East Atlantic, from Norway (Döderlein 1911) to South Africa (Mortensen 1933). It also has a wide bathymetric distribution, ranging from 100 to 4721 m (Smirnov et al. 2014). We collected the species at eleven stations from Western Sahara, Mauritania and Guinea-Bissau waters, between 902 and 1862 m. Remarks This is a deep-sea-water species generally associated with gorgonians and pennatularians (Mortensen 1927). Our specimens were always associated with pennatularians Distichoptilum gracile Verrill, 1882 and Anthoptilum murrayi Kölliker, 1880. Living colour of the species is cream or pinkish orange, more intense in the central part of the disc. The innermost arm spine much larger than the other spines and a hooked arm spine at the tip of the arm are the most distinctive characteristic for this species., Published as part of Calero, Belén & Ramil, Fran, 2023, Euryalida (Echinodermata, Ophiuroidea) from Northwest Africa, pp. 46-75 in European Journal of Taxonomy 870 on pages 51-53, DOI: 10.5852/ejt.2023.870.2117, http://zenodo.org/record/7938618, {"references":["Muller J. & Troschel F. H. 1842. System der Asteriden. F. Vieweg und Sohn, Braunschweig. https: // doi. org / 10.5962 / bhl. title. 11715","Studer T. 1884. Verzeichnis der wahrend der Reise S. M. S. \" Gazelle \" um die Erde, 1874 - 76 gesammelten Asteriden und Euryaliden. Abhandlungen der Preussischen Akademie der Wissenschaften: 1 - 64.","Koehler R. 1895. Draguage profonds executes a bord du ' Caudan' dans le Golfe de Gascogne. Rapport preliminaire sur les Echinodermes. Revue Biologique du Nord de la France VII: 439 - 506.","Clark H. L. 1923. The Echinoderm fauna of South Africa. Annals of The South African Museum XIII: 221 - 432.","Mortensen Th. 1927. Handbook of the Echinoderms of the British Isles. Oxford University Press, Rotterdam. https: // doi. org / 10.5962 / bhl. title. 6841","Paterson G. L. J. 1985. The deep-sea Ophiuroidea of the North Atlantic Ocean. Bulletin of the British Museum (Natural History) 49 (1): 1 - 162.","Koehler R. 1896. Resultats scientifiques de la campagne du Caudan dans le Golfe de Gascogne. Echinodermes. Annales de l'Universite de Lyon 26: 33 - 122. https: // doi. org / 10.5962 / bhl. title. 65730","Hernandez-Herrejon L. A., Solis-Marin F. A. & Laguarda-Figueras A. 2008. Ofiuroideos (Echinodermata: Ophiuroidea) de las aguas mexicanas del golfo de Mexico. Revista De Biologia Tropical 56 (3): 83 - 167.","Doderlein L. 1911. Uber japanische und andere Euryalae. KB Akademie der Wissenschaften, Munich. https: // doi. org / 10.5962 / bhl. title. 16334","Mortensen Th. 1933. Papers from Dr. Th. Mortensen's Pacific Expedition 1914 - 16. LXV. Echinoderms of South Africa (Asteroidea and Ophiuroidea). Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i Kobenhavn: 93: 215 - 400.","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."]}

Astrodendrum juancarlosi sp. nov. urn:lsid:zoobank.org:act: ECD0622E-6FAF-4C72-B102-F1B94D8ECBFB Figs 3E–F, 7–9 Diagnosis Species with small granule-like external ossicles, ending in a crystalline point, covering the dorsal and lateral interradial areas of the disc. Ventral disc areas and arms covered by domed granule-like external ossicles without any crystalline point. Two or three terminal projections on each arm spine; one secondary teeth on each valve. Etymology The specific epithet ‘ juancarlosi ’ was chosen as a tribute to Mr Juan Carlos Calero, father of the first author. Material examined Holotype GUINEA BISSAU • 2 specs, 40.43–56.81 mm dd; 10°18′55″ N, 16°25′07″ W; depth 79 m; 4 Nov. 2008; Bissau-0810 exped.; stn BS200; Bissau-0810-06403; MNCN 29.02/1534. Paratypes GUINEA BISSAU • 2 specs, 28.20–51.16 mm dd; 11°08′07″– 11°09′33″ N, 17°15′20″– 17°15′44″ W; depth 109 m; 29 Oct. 2011; CCLME-1110 exped.; CCLME-1110 exped.; stn BT53; MHN USC-10132 -1 and 2 • 1 spec., 40.43 mm dd; 10°18′55″ N, 16°25′07″ W; depth 79 m; 4 Nov. 2008; Bissau-0810 exped.; Bissau-0810 exped.; stn BS200; MNCN 29.02/1535. WESTERN SAHARA • 1 spec., 44.62 mm dd; 26°26′23″– 26°25′06″ N, 14°25′30″– 14°26′23″ W; depth 67– 58 m; 29 Nov. 2011; CCLME-1110 exped.; CCLME-1110 exped.; stn BT215; CFM-IEOMA-7776. • 1 spec., 46.70 mm dd; 14°57′00″– 14°58′09″ N, 17°39′08″– 17°38′13″ W; depth 797 m; 25 May 2012; CCLME-1205 exped.; CCLME-1205 exped.; stn BT368; CCLME-1205-03248; LZM-UV. Additional material GUINEA BISSAU • 1 spec., 10.07 mm dd; 11°05′09″– 17°03′15″ N, 11°04′15″– 17°03′10″ W; depth 46–47 m; 26 Oct. 2008; Bissau-0810 exped.; stn BS151; Bissau-0810-06146; LZM-UV. Description (holotype) DISC. Five-lobed in shape, slightly excavated inter-radially (Fig. 8A), with no peripheral calcareous plates on rim. Radial shields tumid, long (almost raising the centre of disc) and narrow, which is deeply sunken (Fig. 8C). Radial shields completely concealed by external ossicles, bar-shaped, as wide proximally as distally, but more separated distally, converging towards centre of disc. Distally, radial shields end on enlarged, slightly concave and oval-shaped plate covered by minute granules (Fig. 8C–D). Dorsal disc covered by small granule-like external ossicles (Fig. 8A, C–D), each one ending in terminal crystalline point. At edge of disc, ossicles more densely packed and without crystalline point (Fig. 8C), and bigger in size between radial shields (Fig. 8C–D). Ossicles concealing radial shields similar to those from dorsal disc but more densely packed.Ventral inter-radial areas densely covered by mosaic of small irregular flat plates with granule-like external ossicles without terminal point. Oral shield, adoral shield, oral plates, along edge of mouth frame and ventral arm plates more densely covered by similar external ossicles. Mouth frame sunken (Fig. 8E). Interradial surface of lateral disc covered by external ossicles similar but smaller than those covering dorsal disc. Two large genital slits on each interradius running almost vertically along first five or six brachial segments after first fork (Fig. 8F). Conical external ossicles with terminal crystalline point more developed on adradial edge of genital slits. One oval-shaped and well-developed madreporite located just outside mouth frame (Fig. 8E). Both, tooth and oral papillae spiniform, especially larger apical ones. Mouth and infradental papillae form continuous series along mouth frame (Fig. 8E). Teeth varying in position and size, being irregular in outline and more or less irregularly disposed. ARMS. Arms branching, with first fork before disc margin and second one located at margin. Nevertheless, in smaller specimens (juvenile), first fork located on margin of disc. Arms tapering gradually towards tips, completely covered, both, dorsally and ventrally, by domed granule-like external ossicles (Fig. 9A); these granules somewhat bigger than disc ones and without any crystalline point. Dorsal side of arms carry pedicellarial bands along whole arms. Valves with one secondary tooth downwardly curved (Fig. 9C). Some sunken transverse furrow between segments, giving arms an annulated appearance. Indication observed of median furrow along arm (Fig. 8G). Ventral side of arms with noticeable transverse naked furrows between segments until second fork; afterwards, furrows become smaller, disappearing after third fork. First two pores without arm spine. Arm spines beginning at third pair of pores with only one small spine at third and fourth pair of pores, two arm spines (sometimes one) afterwards and three arm spines (sometimes two) after second fork. Arm spines short and wide, ending in two or three hyaline points (Fig. 9F). Vertebrae streptospondylous (Fig. 9G–K). COLOUR. Living specimens showing varying colours, from creamish-pink to dark orange and brown to gray (Fig. 3E–F) with clear ventral part; preserved specimens are white. OSSICLE MORPHOLOGY. External ossicles on dorsal surface of disc, including radial shields, are granule-shaped and ending in a crystalline point (Fig. 9A). Baseplates oval-shaped with three to five tubercleshaped articulations for pedicellarial (Fig. 9D). External ossicles on baseplates granule-like shaped, approximately 200 µm in length and 100 µm in height (Fig. 9B). Valves with single inner tooth downwardly directed, and reticular structure (Fig. 9C). Lateral arm plates long, bar-like, with tuberculous stereom, spines placed in external lobe of plate (Fig. 9E). Arm spines ovoid-shaped with two or three small projections, not transforming into hook-shaped spines on distal portion (Fig. 9F). Vertebrae with hourglass-shaped streptospondylous articulations (Fig. 9G–K). Branching vertebra wider and with two surfaces for articulation. Distribution This species has been recorded in the Northwest African coast, from the Western Sahara to Guinea-Bissau waters. Its bathymetric distribution ranges between 47 and 797 m. Remarks The genus Astrodendrum was established by Döderlein (1911) for Gornocephalus sagaminus Döderlein, 1902. He realised that all species that belong to Gorgonocephalus Leach 1815 are characterised by the presence of a well-developed belt of calcareous plates at the margins of the disc. However, species of Astrodendrum have no ring of calcareous plates at the rim. Additionally, the arm spines appear before the first fork, as in Gorgonocephalus; however, in Astrodendrum Döderlein, 1911, these arm spines are much smaller, hardly reaching ⅓ of the segment length, and their number is reduced: with three (or rarely four) on each side. Taxonomic studies dealing with this genus are scarce, and we have only found a revision of the genus recently published by Okanishi & Fujita (2018). According to these authors, the genus is characterised by having five branching arms, with less than six segments before the first fork; lack of calcareous plates on the edge of the disc margin; variously shaped external ossicles or no ossicles on the disc; a madreporite placed on the innermost part of the interradial lateral disc; and valves from the dorsal arms with one secondary tooth. Currently, only six species have been assigned to this genus. Among them, only Astrodendrum capense (Mortensen, 1933), described from Durban, South Africa (Mortensen 1933; Clark & Courtman-Stock 1976), has been found in the Atlantic Ocean – Namibia (Alva & Vadon 1989). Astrodendrum elingamita Baker, 1974 has been reported in New Zealand and Philippines (Baker 1974; Okanishi & Fujita 2018); Astrodendrum galapagense A.H. Clark, 1916 from Galapagos Islands; Astrodendrum laevigatum (Koehler, 1897) from Colombo (Sri Lanka); and Astrodendrum sagaminum (Döderlein, 1902) from Japan, East China Sea and Sri Lanka (Döderlein 1902, 1911; Clark 1911; Bomford 1913; Matsumoto 1917; Irimura & Kubodera 1998); and the recently described Astrodendrum spinulosum Okanashi & Fujita, 2018 also from Japan. In addition to the shape, size and arrangement of external ossicles – widely used as an important specific taxonomic character (Baker 1974, 1980; McKnight 2000) – Okanishi and Fujita (2018) included the possibility of the lack of external ossicles (as in the case of A. laevigatum), and they also proposed three new taxonomic characters to distinguish species of Astrodendrum: • absence/ presence of bulges on lateral ridges of proximal portion of arm • number of terminal projections of arm spines on proximal portion of arm • number of secondary teeth of hook-shaped arm spines on distal portion of the arm The main morphological features of all known species of Astrodendrum, including A. juancarlosi sp. nov., are summarized in Table 2. Astrodendrum spinulosum differs from the rest of species by the presence of bulges on lateral ridges of proximal portion of the arm. The new species here described, also differs from A. spinulosum by the number of terminal projections of arm spines on the proximal portion of the arm (three in the case of the new species and one in A. spinulosum). In addition, A. spinulosun has cone-shaped external ossicles, while A. juancarlosi sp. nov. has granule like ossicles ending in a crystalline point at the dorsal surface of the disc. Astrodendrum juancarlosi sp. nov. is more similar to A. elingamita in the shape of the ventral coverage and the lack of a scale in the first tentacle pore. Nevertheless, A. elingamita has the first fork in the margin of the disc, while it is located before the margin in our species. The polygonal plates of the ventral covering are closer in the A. elingamita than in our specimen. Our specimens also differ from A. elingamita by having one type of dome-shaped granules with 1–2 hyaline terminal points rather than two smooth types. Astrodendrum sagaminum differs from Astrodendrum juancarlosi sp. nov. in also having two types of granules and naked arms and ventral disk. Astrodendrum capense has several medium-sized conical tubercles along the radial shields; it also has some smaller conical tubercles along the inter-radial disc margin, both ending in small thorns. Moreover, the disc is closely covered with minute and smooth plates. Astrodendrum galapagense has a dorsal coarse armament on the disc and arms. The external ossicles on the aboral disc are plate-shaped at periphery and conical at center, both slightly in contact, while on the oral surface has a few small widely scattered granules, except in the ventral interbrachial areas. Astrodendrum laevigatum is covered by a thin, transparent, soft and perfectly smooth tegument without any granules or spines. According to the description of this species in the literature, there are some doubts about the inclusion of this species in the genus Astrodendrum. We consider necessary to review the type material before we can reach a conclusion on this issue. Therefore, in this paper we follow Okanishi & Fujita (2018) and keep the species within the genus Astrodendrum. Finally, our specimen has marked rectangular furrows that are absent in the rest of the species of Astrodendrum. Even though Mortensen (1933) described the underside of the arms of A. capense as flat and without any grooves, he pointed out that this “may be an indication of a transverse furrow between the segments from the first forking onwards” (Mortensen 1933: 286). See Table 2 for comparison of main morphological characteristics among species., Published as part of Calero, Belén & Ramil, Fran, 2023, Euryalida (Echinodermata, Ophiuroidea) from Northwest Africa, pp. 46-75 in European Journal of Taxonomy 870 on pages 59-67, DOI: 10.5852/ejt.2023.870.2117, http://zenodo.org/record/7938618, {"references":["Doderlein L. 1911. Uber japanische und andere Euryalae. KB Akademie der Wissenschaften, Munich. https: // doi. org / 10.5962 / bhl. title. 16334","Doderlein L. 1902. Japanische Euryaliden. Zoologischer Anzeiger 25 (659 - 684): 320 - 326.","Okanishi M. & Fujita T. 2018. A taxonomic review of the genus Astrodendrum (Echinodermata, Ophiuroidea, Euryalida, Gorgonocephalidae) with description of a new species from Japan. Zootaxa 4392 (2): 289 - 310. https: // doi. org / 10.11646 / zootaxa. 4392.2.4","Mortensen Th. 1933. Papers from Dr. Th. Mortensen's Pacific Expedition 1914 - 16. LXV. Echinoderms of South Africa (Asteroidea and Ophiuroidea). Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i Kobenhavn: 93: 215 - 400.","Clark A. M. & Courtman-Stock J. 1976. The Echinoderms of Southern Africa. Trustees of the British Museum (Natural History), London.","Alva V. & Vadon C. 1989. Ophiuroids from the western coast of Africa (Namibia and Guinea-Bissau). Scientia Marina 53 (4): 827 - 845.","Baker A. N. 1974. New species of brittle-stars from New Zealand (Echinodermata: Ophiiuroidea). Records of the Dominion Museum 8 (15): 247 - 266.","Clark H. L. 1916. Report on the Sea-Lilies, Starfishes, Brittle-Stars and Sea-Urchins obtained by the F. I. S. ' Endeavour' on the coast of Queensland, New South Wales, Tasmania, Victoria, South Australia, and Western Australia. Biological results of the fishing experiments carried on by the \" Endeavour \" 4 (1). Minister for Trade and Customs, Sydney. hhtps: // doi. org / 10.5962 / bhl. title. 13854","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. https: // doi. org / 10.5479 / si. 03629236.75.1","Bomford T. L. 1913. A note on certain ophiiuroids in the Indian Museum. Records of the Indian Museum 9 (4): 219 - 225.","Matsumoto H. 1917. A monograph of Japanese Ophiuroidea, arranged according to a new classification. Journal of the College of Science, Imperial University, Tokyo, Japan XXXVIII (2): 1 - 407.","Irimura S. & Kubodera T. 1998. Ophiuroidea in the East China Sea. Memoirs of the National Science Museum, Tokyo 31: 135 - 143.","Baker A. N. 1980. Euryalinid Ophiuroidea (echinodermata) from Australia, New- Zealand, and the Southwest Pacific-Ocean. New Zealand Journal of Zoology 7 (1): 11 - 83. https: // doi. org / 10.1080 / 03014223.1980.10423763","McKnight D. G. 2000. The marine fauna of New Zealand: Basket-stars and Snake-stars (Echinodermata: Ophiuroidea: Euryalinida). National Institute of Water and Atmospheric Research, Wellington, New Zealand."]}

Gorgocephalus pustulatum (H.L. Clark, 1916) Figs 10–11 Astrodendrum pustulatum Clark, 1916: 84–85, pl. XXXIV figs 1–2. Gorgonocephalus pustulatum Baker, 1980: 54–56, figs 18B, 20, 30. Gorgonocephalus pectinatus Mortensen, 1933: 281–285, figs. 16–17, pl. XVIII figs. 1–2. Gorgonocephalus pustulatum – Rowe & Gates 1995: 368. — Calero et al. 2018: 3, 8. Gorgonocephalus pectinatus – Clark & Courtman-Stock 1976: 133. Material examined GUINEA BISSAU • 1 spec., 30.45 mm dd; 10°01′18″– 10°00′24″ N, 17°24′56″– 17°25′05″ W; depth 902–908 m; 24 Oct. 2008; Bissau-0810 exped.; stn BS166; Bissau-0810-18012; LZM-UV. Distribution This species has an Indo-Pacific distribution. It has been recorded in South Africa from Cape Province to East London (Mortensen 1933), the Indonesian region (Döderlein 1927) and Flinders Islands (Bass Strait, Australia) (Clark 1916); its bathymetric range extends from 182 (Clark 1916) to 860 m (Clark & Courtman-Stock 1976). Our material was recorded in one station in Guinea-Bissau waters, between 902 and 908 m. This material is the same as that reported by Calero et al. (2018). Description The dorsal side of disc covered by a skin with some scattered tubercles, ending in some small thorns. The same type of tubercles were found on the marginal belt of plates. Radial shields long and bar-shaped, nearly reaching the centre of the disc (Fig. 11A). They are almost completely covered by tubercles similar to those from the interradial areas but slightly bigger (Fig. 11C). The ventral interradial areas are almost fully covered by small granules. Plates of the oral frame swollen and obscured by a thick skin. Oral shields with some scattered small granules. There is a cluster of slender apical papillae flanked on each side by smaller oral papillae. Arms also covered by a skin concealing the plates. First pair of tentacle pores outside the mouth edge, without arm spines. Two arm spines from the second to fifth or sixth pores; afterwards, from the first fork on, three spines. Arm spines are small, less than one arm segment, and with some thorny ends. First fork within the edge of the disc. Dorsally, arms covered by flat granules, and with a longitudinal median furrow (Fig. 11F). Pedicellarial bands along the arms, appearing from the first segments. Remarks Even though the single specimen collected was badly damaged, the presence of the main distinctive features of Gorgonocephalus pustulatum (H.L. Clark, 1916), like the number of spines (max. 4), disc coverage (sparse and low tubercles) or the thin peripheral ring, legitimate our identification to species level. Our finding in Guinea-Bissau represents the first record of G. pustulatum in the Tropical East Atlantic Ocean, extending its geographical distribution to the north, from south Africa to Guinea-Bissau. This station also represents the deepest record for this species (908 m)., Published as part of Calero, Belén & Ramil, Fran, 2023, Euryalida (Echinodermata, Ophiuroidea) from Northwest Africa, pp. 46-75 in European Journal of Taxonomy 870 on pages 67-68, DOI: 10.5852/ejt.2023.870.2117, http://zenodo.org/record/7938618, {"references":["Clark H. L. 1916. Report on the Sea-Lilies, Starfishes, Brittle-Stars and Sea-Urchins obtained by the F. I. S. ' Endeavour' on the coast of Queensland, New South Wales, Tasmania, Victoria, South Australia, and Western Australia. Biological results of the fishing experiments carried on by the \" Endeavour \" 4 (1). Minister for Trade and Customs, Sydney. hhtps: // doi. org / 10.5962 / bhl. title. 13854","Baker A. N. 1980. Euryalinid Ophiuroidea (echinodermata) from Australia, New- Zealand, and the Southwest Pacific-Ocean. New Zealand Journal of Zoology 7 (1): 11 - 83. https: // doi. org / 10.1080 / 03014223.1980.10423763","Mortensen Th. 1933. Papers from Dr. Th. Mortensen's Pacific Expedition 1914 - 16. LXV. Echinoderms of South Africa (Asteroidea and Ophiuroidea). Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i Kobenhavn: 93: 215 - 400.","Rowe F. W. E. & Gates J. 1995. Echinodermata. In: Wells A. (ed.) Zoological Catalogue of Australia Vol. 33. CSIRO Australia xii, Melbourne, Australia.","Calero B., Ramos A. & Ramil F. 2018. Distribution of suspension-feeder brittle stars in the Canary Current upwelling ecosystem (Northwest Africa). Deep Sea Research Part I: Oceanographic Research Papers 142: 1 - 15. https: // doi. org / 10.1016 / j. dsr. 2018.11.001","Clark A. M. & Courtman-Stock J. 1976. The Echinoderms of Southern Africa. Trustees of the British Museum (Natural History), London.","Doderlein L. 1927. Indopacifische Euryalae. Abhandlungen der Bayerischen Akademie der Wissenschaften XXXI (6): 1 - 105. https: // doi. org / 10.1515 / 9783486755459"]}

Egmundella modesta Millard & Bouillon, 1975 (Fig. 4a; Table 2) Lovenella (?)— Millard & Bouillon, 1973: 42–43, fig. 5E–F. Egmundella modesta Millard & Bouillon, 1975: 5–7, fig. 1E–H; Vervoort, 2006: 224–225, figs. 7 no. 3; 8 no. 3; 9d–h. Material examined. Western Sahara. MAROC-0611, stn MO235, 23º12′00″– 23º14′27″N, 17º11′16″– 17º12′27″W, 909–913 m, 27-XI-2006: a colony, 0.85 mm high, growing on Halecium sp., without gonothecae. Description. Colony stolonal, composed of hydrothecae and nematothecae arising from a filiform hydrorhiza. Hydrothecae borne on pedicels of varied length, though most are short, slender, generally smooth, occasionally with 2–5 basal annulations and sometimes a few irregularly-placed, additional annulations along its length, distally widening at junction with the corresponding theca, and there provided with a transverse, thin diaphragm. Hydrotheca deeply campanulate, tapering basally, walls almost parallel, aperture closed by a conical operculum, composed of 8–10 elongate, triangular flaps, independent from one another; flaps may be folded either inwards or outwards and, in this case, the rim is distinctly-marked. Nematothecae irregularly scattered, small, globular, borne on short pedicels, aperture apical, oval. No gonothecae observed. Biology. Egmundella modesta has been reported so far growing on an unidentifiable hydroid fragment (Vervoort 2006). In our material, it was found growing on a species of Halecium. Distribution. This species has previously been found in the Seychelles (Millard & Bouillon 1973, as Lovenella sp.; Millard & Bouillon 1975) and Mauritania (Vervoort 2006). Its bathymetric distribution ranges from the littoral zone (Millard & Bouillon 1975) to 1000 m (Vervoort 2006). Our material was found off Western Sahara at depths from 909 to 913 m. Remarks. The material agrees in morphology with the holotype described by Millard & Bouillon (1975) from the Seychelles and with the CANCAP material of E. modesta studied by Vervoort (2006). In our material most of hydrothecae have short pedicels. However, some hydrothecae are larger in size, and have longer pedicels (Fig 4a). This feature was also described by Vervoort (2006), but we now provide more extensive measurements (see table 2). Largest hydrothecae resemble those of E. grimaldii, but in that species the colonies form rhizocaulomic, stemlike structures, a character not observed in our material, where the hydrorhiza is composed of a single stolon growing on Halecium sp. Moreover, in E. grimaldii the hydrothecal pedicels are shorter and the nematothecae are larger. After comparing material of both species collected during the MAROC surveys, we concluded that the present material is clearly different from E. grimaldii, while fitting well the descriptions of E. modesta found in the literature., Published as part of Gil, Marta & Ramil, Fran, 2023, The genera Egmundella Stechow, 1921 and Cyclocanna Bigelow, 1918 (Cnidaria, Hydrozoa) in waters of Northwest Africa, pp. 490-504 in Zootaxa 5264 (4) on pages 495-496, DOI: 10.11646/zootaxa.5264.4.2, http://zenodo.org/record/7836965, {"references":["Millard, N. A. H. & Bouillon, J. (1975) Additional Hydroids from the Seychelles. Annals of the South African Museum, 69 (1), 1 - 15.","Millard, N. A. H. & Bouillon, J. (1973) Hydroids from the Seychelles (Coelenterata). Annales du Museum Royal de l´Afrique Centrale, Sciences Zoologiques, 206 (8), 1 - 106.","Vervoort, W. (2006) Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania-II expeditions of the National History, Leiden, the Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden, 80, 181 - 318."]}

Egmundella ansini n. sp. (Fig. 5; Table 4) Material examined. Western Sahara. MAROC-0611, stn MO239, 23º28′05″– 23º24′32″N, 17º16′24″– 17º16′22″W, 963–969 m, 28-XI-2006: a colony, 2 mm high, with gonothecae, growing on the stem of an unidentified hydrozoan (Holotype, MNCN 2.03 /687). MAROC-0611, stn MO275, 25º27′17″– 25º29′34″N, 16º22′06″– 16º21′15″W, 1505–1510 m, 9-XII-2006: a colony, 4 mm high, growing on Streptocaulus chonae, one gonotheca present (Paratype, RMNH.COEL.43831). Etymology. The specific name ansini honours our colleague and friend Dr José Ansín-Agís, of the University of Vigo, Spain, in appreciation and recognition of his important contribution to the taxonomy of plumularioid hydroids. Description. Colonies stolonal, composed of hydrothecae, nematothecae and gonothecae arising from filiform hydroriza. Hydrothecae borne on pedicels of varied lengths, though mostly long (Fig. 5a, c–g), smooth, slender, with short basal annulations and occasionally a distally placed, additional annulation; distally widening at junction with the corresponding theca, and there provided with a transverse, thin diaphragm. Hydrotheca deeply campanulate, tapering basally, walls parallel, rim not apparent, aperture closed by a conical operculum composed of 15–18 elongate, triangular flaps, not connected between them, and folded either inwards or outwards. Nematothecae borne irregularly on the hydrorhiza between the hydrothecae; long, slender, without distinct pedicel, aperture distal, circular. Gonothecae arise perpendicularly to the hydrorhiza, tubular, elongate, tapering basally in small undulations, without distinct pedicel, rim imperceptible, aperture distal, closed by a conical operculum composed of 16 elongate triangular flaps, independent from one another (Fig. 5a, c). Biology. In our material, one colony was growing on the hydroid Streptocaulus chonae Ansín Agís, Ramil & Vervoort, 2001. Gonothecae have been observed in November and December. Distribution. Egmundella ansini n. sp. was collected from Western Sahara at depths between 696 and 1510 m. Remarks. This species is clearly different from both E. grimaldii and C. producta (see below) on the account of the shape of gonothecae and the appearance of its colonies. It is also different from E. modesta, which has colonies and pedicels much smaller than those of E. ansini n. sp. Our material resembles in morphology to E. superba, E. magellanica Galea et al., 2019 and the material from the “Galathea” Expedition described by Vervoort (1966) as Egmundella sp. Nevertheless, there are considerable differences in size allowing them to be confidently separated specifically. In E. ansini n. sp. the hydrothecae and pedicels are larger than those of the specimens of E. superba studied herein, and also larger than those described by Calder (1991). Conversely, E. ansini n. sp. has smaller and narrower gonothecae than those of E. magellanica. Also, its hydrothecae are larger and their pedicels slenderer and lacking the twists of E. magellanica (see table 4). Finally, Egmundella sp. from the “Galathea” Expedition (Vervoort 1966) has been only reported from Indonesia, and it seems unlikely that it could be conspecific, given its distribution. In addition, its hydrothecal pedicels have a “few distinct rings” basally (Vervoort 1966: fig. 9a), while in our material there are only some scarcely-defined annulations (Fig. 5a). Moreover, in our material the hydrothecal pedicels are shorter, while the hydrothecae and nematothecae are larger than those of the “Galathea” Expedition (Vervoort, 1966) (see table 4)., Published as part of Gil, Marta & Ramil, Fran, 2023, The genera Egmundella Stechow, 1921 and Cyclocanna Bigelow, 1918 (Cnidaria, Hydrozoa) in waters of Northwest Africa, pp. 490-504 in Zootaxa 5264 (4) on pages 498-500, DOI: 10.11646/zootaxa.5264.4.2, http://zenodo.org/record/7836965, {"references":["Ansin Agis, J., Ramil, F. & Vervoort, W. (2001) Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, the Netherlands. Zoologische Verhandelingen, Leiden, 333, 1 - 268.","Galea, H. R., Schories, D. & Holtheuer, J. (2019) Three new records of hydroids (Cnidaria: Hydrozoa) from southern Chile. Revue suisse de Zoologie, 126 (2), 235 - 247. https: // doi. org / 10.5281 / zenodo. 3463457","Vervoort, W. (1966) Bathyal and abyssal hydroids. Galathea Report. Scientific Results of The Danish Deep-Sea Expedition, 1950 - 1952, 8, 97 - 173.","Calder, D. R. (1991) Shallow-water hydroids of Bermuda. The Thecatae, exclusive of Plumularioidea. Royal Ontario Museum, Life Sciences Contributions, 154, 1 - 140."]}

Stegopoma giganteum Ramil & Vervoort, 1992 Fig. 3D–E; Table 3 Stegopoma giganteum Ramil & Vervoort, 1992: 36–38, fig. 5e–f. Material examined SOUTH ATLANTIC OCEAN • 5 colonies, up to 15 mm high (1 growing on Zygophylax sp., 1 on bivalve shell, 1 on ghost fishing net with a gonotheca); Valdivia Seamount, stn BT12; 24°49′01″–24°47′38″ S, 6°24′40″–6°25′26″ E; 887– 886 m depth; 7 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40222, SEAFO-2015-40612, SEAFO-2015-40811, SEAFO-2015-40827, SEAFO-2015-40852, LZM-UV slide R. 587. Description Colony composed of a thin and ramified stolon, growing attached on the hydrocaulus and branches of Zygophylax sp., from which arise pedicellate hydrothecae and gonothecae. Hydrothecae placed at the end of long, slender, smooth-walled and unbranched pedicels with some transversal scars due to regeneration after damage. Hydrothecae large, tubular, with smooth walls, almost bilaterally symmetrical, and slightly widening distally (Fig. 3D). Aperture closed by a triangular operculum adopting the shape of a gabled roof, formed by two opposite, semicircular sections on the distal part of the hydrothecal wall; opercular apparatus provided with longitudinal strips running downwards from top to basis. Hydranths are damaged or absent, and their description is not possible, but we can confirm that they are attached to the inner side of the hydrothecal base by means of a hyaline membranous ring, identical to the description given by Ramil & Vervoort (1992); this membranous ring indicates the boundary between the pedicel and the hydrotheca. The gonotheca shows similar morphology to that described for the hydrotheca, including the closing apparatus, but it is supported by a shorter pedicel (Fig. 3E). Remarks This is the first record of S. giganteum after its original description. The large size of the hydrothecae (2–3 mm long), with long and narrow pedicels, are distinctive features of this species. In addition, the opercular apparatus, the presence of a hyaline membranous ring at the attachment site of the hydranth to the hydrothecal base, and the gonothecal shape fit well with the original description of this species. Consequently, despite the wide geographical distance between the type locality and the present record, we include this material in S. giganteum. Distribution This species is only known from off Cape São Vicente (Portugal; type locality) where it was collected at a depth of 1523 m (Ramil & Vervoort 1992). This is the first record for the South Atlantic., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 60-61, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262."]}

Sertularella areyi Nutting, 1904 Fig. 4C; Table 8 Sertularella areyi Nutting, 1904: 83, pl. 17 fig. 6. Sertularella annulaventricosa Millard, 1975: 279 –281, fig 91F –H. Sertularella areyi – Vervoort 1993: 201–203, fig. 41c–g. — Vervoort & Watson 2003: 156–158, fig. 35f–i. — Calder 2013: 28–29, fig. 8h. Material examined SOUTH ATLANTIC OCEAN • 5 colonies, up to 5 mm high (2 growing on algae), all without gonothecae; Vema Seamount, stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40407, SEAFO-2015-40513, SEAFO-2015-40768, SEAFO-2015-40798, SEAFO-2015-40882, LZM-UV slide R. 585. Distribution Sertularella areyi is considered as a circumtropical species (Calder 2013). It was reported from the east coast of South Africa by Millard (1975, as Sertularella annulaventricosa Mulder & Trebilcock, 1915), but not from the west coast. Our record from Vema Seamount is the first one in the South Atlantic Ocean. The bathymetric distribution ranges from 47 (Millard 1975, as S. annulaventricosa) to a depth of 480 m (Vervoort 1993)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 68, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Nutting C. C. 1904. American hydroids, Part II. The Sertulariidae. Bulletin of the United States National Museum 4 (2): 1 - 325.","Vervoort W. 1993. Cnidaria, Hydrozoa, Hydroida: hydroids from the Western Pacific (Philippines, Indonesia and New Caldeonia). I: Sertulariidae. (Part I). In: Crosnier A. (ed.) Resultats des Campagnes MUSORSTOM. Memoires du Museum national d'histoire naturelle 11: 89 - 298.","Vervoort W. & Watson J. E. 2003. The marine fauna of New Zealand. Leptothecata (Cnidaria: Hydrozoa) (thecate hydroids). NIWA Biodiversity Memoir 119: 1 - 540.","Calder D. R. 2013. Some shallow-water hydroids (Cnidaria: Hydrozoa) from the central east coast of Florida, USA. Zootaxa 3648 (1): 1 - 72. https: // doi. org / 10.11646 / zootaxa. 3648.1.1"]}

Monotheca bergstadi sp. nov. urn:lsid:zoobank.org:act: 3BFDE359-6A4B-4910-9AB5-226193B6584E Figs 7C–D, 8; Table 12 Plumularia pulchella – Millard 1957: 232; 1962: 300; 1966: 493; 1975: 398–399, fig. 125c–d [not Monotheca pulchella (Bale, 1882)]. Diagnosis Colonies monosiphonic, mostly unbranched. Hydrocaulus divided into internodes by straight nodes, each internode bearing one apophysis and three nematothecae. Hydrocladia composed of two internodes: one athecate proximal without nematothecae, with two internal perisarcal rings, and one thecate distal bearing a hydrotheca and three nematothecae. Hydrotheca deep campanulate and abcauline wall concave. Mesial inferior nematotheca long and lateral nematothecae short. Gonothecae arising frontally, large, barrel-shaped and smooth-walled. Etymology The specific name bergstadi honours Dr. Odd Aksel Bergstad, Institute of Marine Research (IMR), Bergen, Norway, leader of the SEAFO 2015 cruise, in recognition of his wide contribution to deep-sea research. Material examined Holotype SOUTH ATLANTIC OCEAN • colony, 10 mm high, with gonothecae; Vema Seamount, stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; LZM- UV slide R. 582; SAMC-A092083. Paratypes SOUTH ATLANTIC OCEAN • 7 colonies, 8–13 mm high (2 growing on algae), 3 colonies, with gonothecae; same collection data as for holotype; SEAFO-2015-40042, SEAFO-2015-40167, SEAFO-2015-40572, SEAFO-2015-40768. Additional material SOUTH ATLANTIC OCEAN • 1 colony, 10 mm high growing on algae, with gonothecae; Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40137 • 1 colony, growing on bryozoan, without gonothecae; Vema Seamount, stn GRAB9C; 31°36′09″ S, 8°22′29″ E; 84 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40080 • 1 colony, without gonothecae; Vema Seamount, stn GRAB12B; 31°37′56″ S, 8°23′12″ E; 89 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40245. Description Colonies composed of a reticulate hydrorhiza growing on algae and a bryozoan, supporting erect, monosiphonic and mostly unbranched, occasionally branched once, hydrocauli (Fig. 7C). Stem regularly divided into internodes by straight nodes, each bearing a latero-distal apophysis and three nematothecae: two axillar, flanking the apophysis and one on the basal half on the opposite side. Apophyses alternately directed left and right and disposed almost in the same plane (Fig. 8A). Hydrocladia inserted on apophyses and composed of two internodes: one athecate basal and one thecate distal. Basal internode short, without nematothecae and with two internal perisarcal rings, one basal and the other distal. Thecate internode slightly longer than athecate, with one hydrotheca and three nematothecae: one mesial inferior and a pair of laterals (Figs 7D, 8A). Hydrotheca deep campanulate, adcauline wall fully adnate to internode, abcauline wall concave, margin straight, smooth and slightly flared. Mesial nematotheca long, reaching or even surpassing the middle of the abcauline wall of hydrotheca. Lateral nematothecae comparatively shorter and placed on small, yet distinct apophyses reaching the hydrothecal rim (Fig. 7D). All nematothecae two-chambered and movable; rim of upper chamber even throughout. Gonothecae arising frontally from apophyses of hydrocladia; large, barrel-shaped, smooth-walled, truncated apically; aperture wide and circular; operculum not observed (Figs 7C, 8B–C). Remarks The validity of the genus Monotheca or its synonymy with Plumularia Lamarck, 1816 has been widely discussed during the last few years in the literature. Watson (2011) and Calder (2019) indicated that, despite the traditional interpretation of the genus, Monotheca might involve a polyphyletic group. Indeed, some molecular analyses (Leclère et al. 2007, 2009; Moura et al. 2008; Maronna et al. 2016) revealed that the type species of both genera, Monotheca margaretta Nutting, 1900 and Plumularia setacea (Linnaeus, 1758), respectively, did not cluster together. In addition, the latest molecular study of the superfamily Plumularioidea (Moura et al. 2018) supports the validity of Monotheca. Taking into account that the new species is closely allied to M. margaretta, we have decided to assign it to this genus, under the name Monotheca bergstadi sp. nov. Our material is closely related to four nominal species of Monotheca, namely M. margaretta Nutting, 1900, M. pulchella (Bale, 1882), M. flexuosa (Bale, 1894) and M. femina (García, Aguirre & González, 1978). The latter is currently accepted as a junior synonym of M. margaretta (Calder 1977; Ansín Agís et al. 2001; Schuchert 2020; as Plumularia margaretta), and we agree. The remaining valid species are easily recognizable by the morphology of their gonothecae. In M. margaretta, they are barrel-shaped, with well-developed transverse ridges and a broad, apical aperture (Calder 1997; Ansín Agís et al. 2001); in M. pulchella the gonothecae are ovate, with an obliquely truncate aperture with a submarginal row of large, internal teeth surrounded by large, internal teeth (Bale 1882; Ralph 1961; Watson 1973, 2011); finally, in M. flexuosa, the gonothecae are fusiform, with slightly undulated walls and a rather small, apical aperture produced into a neck of variable height (Bale 1894; Watson 2011). In addition, M. margaretta is an amphi-Atlantic species, whereas M. pulchella and M. flexuosa are predominately Indo-Pacific. Nevertheless, M. pulchella was reported several times from the Atlantic Ocean and Mediterranean Sea (for a review, see Calder 1997 and Ansín Agís et al. 2001), and the actual status of these records have been subjected to different interpretations in the literature. The records from the Northeast Atlantic and the Mediterranean Sea, all with annulated and barrel-shaped gonothecae, were included in M. margaretta by Calder (1997) and Ansín Agís et al. (2001), and we agree with this conclusion, despite the fact that Watson (2011) considers that they are conspecific with M. flexuosa. The records of M. pulchella from the Mediterranean (Bouillon et al. 2004) are based on the material studied by García Corrales et al. (1978, as Plumularia femina) and Medel & Vervoort (1995), and belong to M. margaretta, despite some figures (Bouillon et al. 2004: fig. 92h, j) being based on Millard (1975: fig. 125c–d) and representing a different species (see below). The records of M. pulchella from the Argentinian coast (Blanco 1973, 1994; Genzano 1990, 1994; all as Plumularia pulchela), were provisionally placed under M. margaretta by Ansín Agís et al. (2001) because the involved colonies were sterile. The morphology of the colonies collected at the Vema Seamount studied in this report, with respect to their tropho- and gonosome, completely coincides with those described by Millard (1975) as M. pulchella from South Africa and the Vema Seamount. This material, characterized by its barrel-shaped, smooth-walled gonothecae, is clearly distinct from the current concept of M. pulchella, and also from other previously discussed species. In fact, Watson (2011) excluded the South African records from the synonymy of M. pulchella, but did not assign them to any known species of Monotheca. Consequently, we consider that this material represents a new species, for which we propose the name M. bergstadi sp. nov. Distribution Monotheca bergstadi sp. nov. has previously been reported from Vema Seamount (Millard 1966, as Plumularia pulchella) and South Africa, from the west coast of Cape Peninsula to Natal (Millard 1957, 1962, 1975; all as P. pulchella). Its bathymetric distribution extends from the littoral zone to a depth of 100 m (Millard 1975, as P. pulchella)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 78-82, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Millard N. A. H. 1957. The Hydrozoa of False Bay, South Africa. Annals of the South African Museum 43: 173 - 243.","Millard N. A. H. 1962. The Hydrozoa of the south and west coasts of South Africa. Part I. The Plumulariidae. Annals of the South African Museum 46 (11): 261 - 319.","Millard N. A. H. 1966. Hydroids of the Vema Seamount. Annals of the South African Museum 48: 489 - 496.","Bale W. M. 1882. On the Hydroida of south-eastern Australia, with descriptions of supposed new species, and notes on the genus Aglaophenia. Journal of the Microscopical Society of Victoria 2 (1): 15 - 48.","Watson J. E. 2011. Review of the genus Monotheca (Hydrozoa: Leptolida) from Australia with description of a new species and a note on Monothecella Stechow, 1923. Memoirs of Museum Victoria 68 (1): 71 - 91. https: // doi. org / 10.24199 / j. mmv. 2011.68.05","Calder D. R. 2019. On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA. Zootaxa 4689 (1): 1 - 141. https: // doi. org / 10.11646 / zootaxa. 4689.1.1","Leclere L., Schuchert P. & Manuel M. 2007. Phylogeny of the Plumularioidea (Hydrozoa, Leptothecata): evolution of colonial organization and life cycle. Zoologica Scripta 36: 371 - 394. https: // doi. org / 10.1111 / j. 1463 - 6409.2007.00283. x","Leclere L., Schuchert P., Cruaud C., Couloux A. & Manuel M. 2009. Molecular phylogenetics of Thecata (Hydrozoa, Cnidaria) reveals long-term maintenance of life history traits despite high frequency of recent character changes. Systematic Biology 58: 509 - 526. https: // doi. org / 10.1093 / sysbio / syp 044","Moura C. J., Harris D. J., Cunha M. R. & Rogers A. D. 2008. DNA barcoding reveals cryptic diversity in marine hydroids (Cnidaria, Hydrozoa) from coastal and deep-sea environments. Zoologica Scripta 37: 93 - 108. https: // doi. org / 10.1111 / j. 1463 - 6409.2007.00312. x","Maronna M. M., Miranda T. P., Pena Cantero A. L., Barbeitos M. S. & Marques A. C. 2016. Towards a phylogenetic classification of Leptothecata (Cnidaria, Hydrozoa). Scientific Reports 6: 1 - 23. https: // doi. org / 10.1038 / srep 18075","Linnaeus C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. L. Salvius, Stockholm. https: // doi. org / 10.5962 / bhl. title. 542","Moura C. J., Lessios H., Cortes J., Nizinski M. S., Reed J., Santos R. S. & Collins A. G. 2018. Hundreds of genetic barcodes of the species-rich hydroid superfamily Plumularioidea (Cnidaria, Medusozoa) provide a guide toward more reliable taxonomy. Scientific Reports 8 (1): 1 - 14. https: // doi. org / 10.1038 / s 41598 - 018 - 35528 - 8","Bale W. M. 1894. Further notes on Australian hydroids, with descriptions of some new species. Proceedings of the Royal Society of Victoria 6: 93 - 117.","Garcia Corrales P., Aguirre Inchaurbe A. & Gonzalez Mora D. 1978. Contribucion al conocimiento de los hidrozoos de las costas espanolas. Parte I: Halecidos, campanularidos y plumularidos. Boletin del Instituto Espanol de Oceanografia 5 (273): 5 - 73.","Ansin Agis J., Ramil F. & Vervoort W. 2001. Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, The Netherlands. Zoologische Verhandelingen, Leiden 333: 1 - 268.","Schuchert P. 2020. World Hydrozoa Database. Available from http: // www. marinespecies. org / hydrozoa / [accessed 14 Jan. 2021].","Calder D. R. 1997. Shallow-water hydroids of Bermuda: superfamily Plumularioidea. Life Sciences Contributions of the Royal Ontario Museum 161: 1 - 85.","Ralph P. M. 1961. New Zealand thecate hydroids, pt. III. Family Sertulariidae. Transactions and Proceedings of the New Zealand Institute 88 (4): 749 - 838.","Watson J. E. 1973. Pearson Island Expedition, 1969. - 9. Hydroids. Transactions of the Royal Society of South Australia 97 (3): 153 - 200. Available from https: // www. biodiversitylibrary. org / page / 41079927 [accessed 15 Jun. 2021].","Bouillon J., Medel M. D., Pages F., Gili J. M., Boero F. & Gravili C. 2004. Fauna of the Mediterranean Hydrozoa. Scientia Marina 68 (2): 5 - 438. https: // doi. org / 10.3989 / scimar. 2004.68 s 25","Medel M. D. & Vervoort W. 1995. Plumularian hydroids (Cnidaria: Hydrozoa) from the strait of Gibraltar and nearby areas. Zoologische Verhandelingen, Leiden 300: 1 - 72.","Blanco O. M. 1973. Nuevos plumularidos para aguas Argentinas. Neotropica 19: 73 - 78.","Blanco O. M. 1994. Enumeracion sistematica y distribucion geografica preliminar de los Hydroida de la Republica Argentina. Suborden Athecata (Gymnoblastea, Anthomedusae), Thecata (Calyptoblastea, Leptomedusae) y Limnomedusae. Revista del Museo de La Plata 14 (161): 181 - 216.","Genzano G. N. 1990. Hidropolipos (Cnidaria) de Mar del Plata, Argentina. Neritica 5 (1): 35 - 54.","Genzano G. N. 1994. La comunidad hidroide del intermareal rocoso de Mar del Plata (Argentina). I. Estacionalidad, abundancia y periodos reproductivos. Cahiers de Biologie marine 35 (3): 289 - 303."]}

Amphisbetia minima (Thompson, 1879) Fig. 4B; Table 7 Sertularia minima Thompson, 1879: 104���105, pl. 17 fig. 3. Amphisbetia minima ��� Millard 1975: 250, fig. 82h���k. ��� Galea & Schories 2012: 36, fig. 3n���o. Material examined SOUTH ATLANTIC OCEAN ��� 2 colonies, growing on algae (1 with gonothecae); Vema Seamount, stn BT5; 31��37���16������31��36���58��� S, 8��22���37������8��23���06��� E; 71���94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40617, SEAFO-2015-40768, LZM-UV slide R. 584. Remarks The presence of ���pores��� or ���holes��� surrounded by a low perisarcal collar below various hydrothecae and usually located at the proximal internodes of the colonies was described by Ralph (1961), Millard (1975) and Vervoort & Watson (2003), but we have not observed any ���pores��� in our colonies. Nevertheless, these pores seem to be a variable feature in this species, as Vervoort & Watson (2003), after reviewing a large amount of material from New Zealand, stated that in some cases there is a pair of holes in the basalmost internode, but other colonies have a single pore or none at all. This structure has been interpreted as nematothecae (Ralph 1961), comparable to the mamelon of Plumularidae (Millard 1975), or glandular pores (Vervoort & Watson 2003), but their true significance remains unknown. Distribution Amphisbetia minima is considered as a circumglobal species, without records from Arctic and Antarctic waters (Millard 1975; Vervoort & Watson 2003). In the South Atlantic, it was reported from Vema Seamount (Millard 1966), the west coast of South Africa (Millard 1975) and the Tristan da Cunha group of islands (Galea 2010, 2015). Its bathymetric distribution extends from the littoral zone to 664 m depth (Vervoort & Watson 2003)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 67-68, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Thompson d'Arcy W. 1879. On some new and rare hydroid zoophytes (Sertulariidae and Thuiariidae) from Australia and New Zealand. The Annals and Magazine of Natural History, Series 5 3 (14): 97 - 114. https: // doi. org / 10.1080 / 00222937908682487","Galea H. R. & Schories D. 2012. Some hydrozoans (Cnidaria) from Central Chile and the Strait of Magellan. Zootaxa 3296 (1): 19 - 67. https: // doi. org / 10.11646 / zootaxa. 3296.1.2","Ralph P. M. 1961. New Zealand thecate hydroids, pt. III. Family Sertulariidae. Transactions and Proceedings of the New Zealand Institute 88 (4): 749 - 838.","Vervoort W. & Watson J. E. 2003. The marine fauna of New Zealand. Leptothecata (Cnidaria: Hydrozoa) (thecate hydroids). NIWA Biodiversity Memoir 119: 1 - 540.","Millard N. A. H. 1966. Hydroids of the Vema Seamount. Annals of the South African Museum 48: 489 - 496.","Galea H. R. 2010. Additional shallow-water thecate hydroids (Cnidaria: Hydrozoa) from Guadeloupe and Les Saintes, French Lesser Antilles. Zootaxa 2570 (1): 1 - 40. https: // doi. org / 10.11646 / zootaxa. 2570.1.1"]}

Eudendrium ramosum (Linnaeus, 1758) Tabularia ramosum Linnaeus, 1758: 804. Eudendrium ramosum – Marques et al. 2000: 104, figs 75–78. — Schuchert 2012: 322–323, fig. 281. Material examined SOUTH ATLANTIC OCEAN • 9 colonies, 7–44 mm high (2 growing on ghost fishing net), 8 of them with gonophores; Valdivia Seamount, stn BT12; 24°49′01″–24°47′38″ S, 6°24′40″–6°25′26″ E; 887– 886 m depth; 7 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40252, SEAFO-2015-40402, SEAFO-2015-40737, SEAFO-2015-40811, SEAFO-2015-40852. Distribution Eudendrium ramosum is considered as a cosmopolitan species by Bouillon et al. (2006), but many records are likely doubtful (Ramil & Vervoort 1992; Marques et al. 2000). Schuchert (2012) indicated that all records outside the East Atlantic (Arctic to South Africa, including the Mediterranean) need confirmation. The bathymetrical distribution of the species extends from intertidal areas (Ansín Agís 1992) to a depth of 1870 m (Ramil & Vervoort 1992)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 55, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Linnaeus C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. L. Salvius, Stockholm. https: // doi. org / 10.5962 / bhl. title. 542","Schuchert P. 2012. North-West European Athecate Hydroids and their Medusae. In: Crothers J. H. & Haywars P. J. (eds) Synopses of the British Fauna (New Series) 59. Field Studies Council, London.","Bouillon J., Gravili C., Pages F., Gili J. M. & Boero F. 2006. An Introduction to Hydrozoa. Memoires du Museum national d'Histoire naturelle, Paris 194: 1 - 591.","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Ansin Agis J. 1992. Hidrozoos de la Ria de Vigo. PhD thesis, Universidad de Vigo, Spain."]}

Sertularella polyzonias (Linnaeus, 1758) Fig. 4D Sertularia polyzonias Linnaeus, 1758: 813. Sertularella polyzonias – Ramil & Vervoort 1992: 225–227, fig. 63a–b. — Cornelius 1995: 74–76, fig. 17. Material examined SOUTH ATLANTIC OCEAN • 5 colonies, 6–13 mm high (2 growing on algae and 2 on bryozoan), 3 of them bear gonothecae; Vema Seamount, stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40197, SEAFO-2015-40347, SEAFO-2015-40387, SEAFO-2015-40602, SEAFO-2015-40768, LZM-UV slide R. 583. Distribution Sertularella polyzonias is a circumglobal species (Gil 2017). In the Southeast Atlantic, it was reported from Angola by Broch (1914). Its bathymetric distribution ranges from 2 (Peña Cantero & García Carrascosa 2002) to 2500 m (Fraser 1944)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 71, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Linnaeus C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. L. Salvius, Stockholm. https: // doi. org / 10.5962 / bhl. title. 542","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Cornelius P. F. S. 1995. North-West European Thecate Hydroids and their Medusae. Part 2. Sertulariidae to Campanulariidae. In: Barnes R. S. K. & Crothers J. H. (eds) Synopses of the British Fauna (New Series) 50. Field Studies Council, London.","Broch H. 1914. Hydrozoa benthonica. In: Michaelsen W. (ed.) Beitrage zur Kenntnis der Meeresfauna Westafrikas. Volume 1: 19 - 50. L. Friederichsen & Co., Hamburg.","Pena Cantero A. L. & Garcia Carrascosa A. M. 2002. The benthic hydroid fauna of the Chafarinas Islands (Alboran Sea, western Mediterranean). Zoologische Verhandelingen, Leiden 337: 1 - 180.","Fraser C. M. 1944. Hydroids of the Atlantic Coast of North America. University of Toronto Press, Toronto."]}

Amphisbetia distans (Lamouroux, 1816) Dynamena distans Lamouroux, 1816: 180, pl. 5 fig. 1. Sertularia distans – Broch 1914: 34. Sertularia distans – Millard 1975: 306–307, fig. 99e–h. — Ramil & Vervoort 1992: 227–228, fig. 63c. Tridentata distans – Calder 1991: 105–107, fig. 55. — Cornelius 1995: 108–111, fig. 27. Material examined SOUTH ATLANTIC OCEAN • 4 colonies, 4–5 mm high (3 growing on algae, 1 of them with gonothecae); Vema Seamount, stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71– 94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40377, SEAFO-2015-40437, SEAFO-2015-40768, SEAFO-2015-40912, LZM-UV slide R. 578 • 1 colony, without gonothecae; Vema Seamount, stn GRAB11A; 31°37′55″ S, 8°21′48″ E; 64 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40853 • 1 colony, without gonothecae; Vema Seamount, stn Dive 4; 91–95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40661. Distribution Amphisbetia distans was considered as a circumtropical species by Ramil & Vervoort (1992, as Sertularia distans), and circumglobal by Calder (1991, as Tridentata distans). In the southeastern Atlantic, it is known from Angola (Broch 1914, as S. distans), Vema Seamount (Millard 1966, as S. distans gracilis) and South Africa (Millard 1975, as S. distans). Its bathymetric distribution ranges from 0 (Millard 1975; Cornelius 1995, as Tridentata distans) to 826 m (Ramil & Vervoort 1992)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 67, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Lamouroux J. V. F. 1816. Histoire des Polypiers coralligenes flexibles, vulgairement nommes Zoophytes. F. Poisson, Caen. https: // doi. org / 10.5962 / bhl. title. 11172","Broch H. 1914. Hydrozoa benthonica. In: Michaelsen W. (ed.) Beitrage zur Kenntnis der Meeresfauna Westafrikas. Volume 1: 19 - 50. L. Friederichsen & Co., Hamburg.","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Calder D. R. 1991. Shallow-water hydroids of Bermuda. The Thecatae, exclusive of Plumularioidea. Life Sciences Contributions of the Royal Ontario Museum 154: 1 - 140.","Cornelius P. F. S. 1995. North-West European Thecate Hydroids and their Medusae. Part 2. Sertulariidae to Campanulariidae. In: Barnes R. S. K. & Crothers J. H. (eds) Synopses of the British Fauna (New Series) 50. Field Studies Council, London.","Millard N. A. H. 1966. Hydroids of the Vema Seamount. Annals of the South African Museum 48: 489 - 496."]}

Genus Monostaechoides gen. nov. urn:lsid:zoobank.org:act: E7E0F40E-8573-4EDF-98F5-D3CD4EAA3ED2 Type species Plumularia providentiae Jarvis, 1922, designated herein. Additional species Monostaechoides bertoti (Galea & Ferry, 2015) gen. et comb. nov. (= Monostaechas bertoti Galea & Ferry, 2015). Diagnosis Halopteridids with monosiphonic hydrocladia arising directly from creeping stolons. Hydrocladia branched, with several cladia originating dorsally from the distal parts of its ahydrothecate internodes. All cladia directed towards the same side or arranged either alternately or irregularly left and right along the stem. Branches of second and third order frequent in, at least, one species. Hydrothecate internodes with one hydrotheca, two pairs of lateral nematothecae and one mesial inferior nematotheca. Ahydrothecate internodes with a variable number of nematothecae. Hydrotheca partly adnate to its corresponding internode, cup-shaped, with untoothed rim. All nematothecae conical, bithalamic and movable. Gonothecae provided with nematothecae on the basal part. Etymology The generic name Monostaechoides is derived from a combination of the generic name Monostaechas Allman, 1877, and the latinized form of the Greek word-forming element ‘- eidés ’, meaning ‘like, resembling’ and referring to the affinities of the new taxon with the genus Monostaechas. The gender of the name is masculine. Remarks The presence of hydrothecae on the hydrocaulus is the main defining character of the family Halopterididae Millard, 1962 (Millard 1962, 1975; Schuchert 1997), and the generic limits within the family are largely based on the shape of the colonies and their ramification patterns (Schuchert 1997). The new genus described herein is characterized by having monosiphonic stems or primary hydrocladia arising from hydrorhiza and supporting irregularly pinnate or unilaterally-arranged secondary hydrocladia that, in turn, can originate hydrocladia of second and third order, in at least the type species. Another distinctive feature is the origin of the subsidiary hydrocladia from the postero-distal parts of ahydrothecate internodes, on the backside of an oblique distal node. The general habit of the colonies, with single monosiphonic stems carrying laterally-placed hydrocladia, resembles those of Halopteris Allman, 1877, Monostaechas Allman, 1877 and the recently described Thamnopteros Galea, 2020. Resemblances with Halopteris are found in the ramified nature of the colonies belonging to both genera, but in Halopteris the hydrocladia are routinely arranged in either alternate or opposite pairs, and originate from the hydrothecate internodes of the stem, laterally to the hydrothecae. Thamnopteros builds polysiphonic colonies giving rise to monosiphonic branchlets bearing pinnate hydrocladia with the same origin as in Halopteris (Galea & Maggioni 2020). The new genus shows more affinities with Monostaechas Allman, 1877 in both the origin of subsidiary hydrocladia on the postero-distal part of ahydrothecate internodes, just behind the distal oblique node, and the tendency to a unilateral disposition of subsidiary hydrocladia. Nevertheless, in Monostaechas the ramification pattern is a helicoid or scorpioid sympodium, in which each subsidiary hydrocladium originates from the postero-distal part of the first ahydrothecate internode of the previous hydrocladium (Billard 1913; Millard 1975; Schuchert 1997), resulting in a false axis composed of the basal parts of successive hydrocladia (Billard 1913; Millard 1975). In Monostaechoides gen. nov., there is a ‘true axis’ represented by a stem or primary hydrocladium bearing several secondary hydrocladia irregularly disposed along the same axis. This branching pattern is clearly different from that displayed by Monostaechas, supporting the creation of a new genus. The colonies of Monostaechas fisheri Nutting, 1906, recently redescribed by Galea & Maggioni (2020), show another ramification pattern, different from that met with in Monostaechoides gen. nov. In this case, the stem is devoid of hydrothecae and the lateral ramification builds a true sympodium (see Billard 1913: fig. 7). The same type of ramification found in Monostaechoides gen. nov. was also described in specimens of Antennella secundaria (Gmelin, 1791) collected from Indonesia (Billard 1913: 8, pl. 1 figs 2–3), the Seychelles (Millard & Bouillon 1973: 78) and South Africa (Millard 1975: 334), suggesting the existence of other undescribed species within this genus. Both Billard (1913) and Millard (1975) pointed out that, in these colonies, the main axis is formed by the first hydrocladium, and does not originate from the basal part of successive hydrocladia, excluding these materials from Monostaechas. Ramified colonies assigned to A. secundaria were also described by Vervoort & Vasseur (1977: 66, fig. 28b), Ryland & Gibbons (1991: 526, fig. 1a) and Calder (1997: 30, fig. 7a), but, in all cases, the ramification fits well with a sympodial pattern and was clearly different from that in Monostaechoides gen. nov., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 71-72, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Jarvis F. E. 1922. The hydroids from the Chagos, Seychelles and other islands and from the coasts of British East Africa and Zanzibar. Transactions of the Royal Society of London, Zoology 18 (1): 331 - 360. https: // doi. org / 10.1111 / j. 1096 - 3642.1922. tb 00553. x","Galea H. R. & Ferry R. 2015. Notes on some hydroids (Cnidaria) from Martinique, with descriptions of five new species. Revue suisse de Zoologie 122 (2): 213 - 246. https: // doi. org / 10.5281 / zenodo. 29998","Millard N. A. H. 1962. The Hydrozoa of the south and west coasts of South Africa. Part I. The Plumulariidae. Annals of the South African Museum 46 (11): 261 - 319.","Schuchert P. 1997. Review of the family Halopterididae (Hydrozoa, Cnidaria). Zoologische Verhandelingen, Leiden 309: 1 - 161.","Galea H. R. & Maggioni D. 2020. Plumularioid hydroids (Cnidaria: Hydrozoa) from off New Caledonia collected during KANACONO and KANADEEP expeditions of the French Tropical Deep-Sea Benthos Program. European Journal of Taxonomy 708: 1 - 58. https: // doi. org / 10.5852 / ejt. 2020.708","Billard A. 1913. Les hydroides de l'expedition du Siboga, I. Plumulariidae. Siboga-Expeditie 7: 1 - 115.","Vervoort W. & Vasseur P. 1977. Hydroids from French Polynesia with notes on distribution and ecology. Zoologische Verhandelingen, Leiden 159: 3 - 98.","Ryland J. S. & Gibbons M. J. 1991. Intertidal and shallow water hydroids from Fiji, II. Plumulariidae and Aglaopheniidae. Memoirs of the Queensland Museum 30 (3): 525 - 560.","Calder D. R. 1997. Shallow-water hydroids of Bermuda: superfamily Plumularioidea. Life Sciences Contributions of the Royal Ontario Museum 161: 1 - 85."]}

Obelia geniculata (Linnaeus, 1758) Sertularia geniculata Linnaeus, 1758: 812. Laomedea geniculata – Broch 1914: 37. Obelia geniculata – Millard 1975: 229–230, fig. 75a–b. — Cornelius 1995: 301–303, fig. 70. — Calder 2012: 50–51, fig. 53. Material examined SOUTH ATLANTIC OCEAN •3 colonies, up to 5 mm high (all growing on brown algae, 2 colonies, with gonothecae); Vema Seamount, stn BT5; 31°37′16″– 31°36′58″ S, 8°22′37″– 8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40317, SEAFO-2015-40327, SEAFO-2015-40768. Distribution Usually considered as a cosmopolitan species, with records from all oceans (Peña Cantero & García Carrascosa 2002), although absent from Antarctic waters (Peña Cantero 2004). In the Southeast Atlantic, it was recorded from Namibia (Broch 1914, as Laomedea geniculata (Linnaeus, 1758)), Vema Seamount (Millard 1966) and South Africa (Millard 1975). Its bathymetric distribution extends from the intertidal (Cornelius 1995) to 381 m (Gili et al. 1989)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 66, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Linnaeus C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. L. Salvius, Stockholm. https: // doi. org / 10.5962 / bhl. title. 542","Broch H. 1914. Hydrozoa benthonica. In: Michaelsen W. (ed.) Beitrage zur Kenntnis der Meeresfauna Westafrikas. Volume 1: 19 - 50. L. Friederichsen & Co., Hamburg.","Cornelius P. F. S. 1995. North-West European Thecate Hydroids and their Medusae. Part 2. Sertulariidae to Campanulariidae. In: Barnes R. S. K. & Crothers J. H. (eds) Synopses of the British Fauna (New Series) 50. Field Studies Council, London.","Calder D. R. 2012. On a collection of hydroids (Cnidaria, Hydrozoa, Hydroidolina) from the west coast of Sweden, with a checklist of species from the region. Zootaxa 3171 (1): 1 - 77. https: // doi. org / 10.11646 / zootaxa. 3171.1.1","Pena Cantero A. L. & Garcia Carrascosa A. M. 2002. The benthic hydroid fauna of the Chafarinas Islands (Alboran Sea, western Mediterranean). Zoologische Verhandelingen, Leiden 337: 1 - 180.","Millard N. A. H. 1966. Hydroids of the Vema Seamount. Annals of the South African Museum 48: 489 - 496.","Gili J. M., Vervoort W. & Pages F. 1989. Hydroids from the West African coast: Guinea Bissau, Namibia and South Africa. Scientia Marina 53 (1): 67 - 112."]}

Campanularia africana Stechow, 1923 Fig. 3G–H; Table 5 Campanularia africana Stechow, 1923: 104. Campanularia africana – Leloup 1938: 13–14, fig. 9. — Millard 1975: 204, fig. 67a. Material examined SOUTH ATLANTIC OCEAN • 2 colonies, growing on algae, without gonothecae; Vema Seamount, stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40437, SEAFO-2015-40768, LZM-UV slide R. 577. Distribution Campanularia africana has previously been reported from Australia (Watson 1990), Japan (Stechow 1923; Leloup 1938; Hirohito 1995) and Natal, South Africa (Millard 1975). Its bathymetric distribution extends from the littoral area to a depth of 102 m (Millard 1975; Stechow 1925). Our finding of C. africana at Vema Seamount represents the first record of this species for the Atlantic Ocean., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 62, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Stechow E. 1923. Uber Hydroiden der Deutschen Tiefsee-Expedition, nebst Bemerkungen uber einige andre Formen. Zoologischer Anzeiger 53 (9 - 10): 223 - 236.","Leloup E. 1938. Quelques hydropolypes de la baie de Sagami, Japon. Bulletin du Musee royal d'Histoire naturelle de Belgique 14 (28): 1 - 22.","Watson J. E. 1990. Studies on Australian Hydroids. The genus Eudendrium and the fauna of the seagrass Amphibolis. Unpublished D. Phil. Thesis, University of Deaking.","Hirohito Emperor of Japan. 1995. Hydroids of Sagami Bay II. Thecata. Publications of the Biological Laboratory, Imperial Household, Tokyo.","Stechow E. 1925. Hydroiden der Deutschen Tiefsee-Expedition. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition auf dem Dampfer \" Valdivia \" 1898 - 1899 27: 383 - 546."]}

Campanulina denticulata Clarke, 1907 Fig. 3F; Table 4 Campanulina denticulata Clarke, 1907: 12–13, pl. 8. Campanulina denticulata – Stechow 1913: 122–123, fig. 92. Opercularella denticulata – Vervoort 1966: 104–106, figs 4–5. Material examined SOUTH ATLANTIC OCEAN • 2 colonies, up to 10 mm high (1 growing on ghost fishing net) and with gonothecae; Valdivia Seamount, stn BT12, 24°49′01″– 24°47′38″ S, 6°24′40″– 6°25′26″ E; 887– 886 m depth; 7 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40811, SEAFO-2015-40887. Remarks Campanulina denticulata was considered a synonym of Earleria panicula (G.O. Sars, 1874) by several authors (Leloup 1974; Schuchert 2003), but Calder (2012) suggested that the Atlantic E. panicula is a different species from the Indo-Pacific C. denticulata. The comparison of the material from the Valdivia Seamount with colonies of E. panicula collected in NW Africa showed some morphological differences, and agrees with descriptions of C. denticulata given by Clarke (1907) and Vervoort (1966). Distribution Campanulina denticulata has an Indo-Pacific distribution (Calder 2012). Its bathymetric distribution extends from more than 500 m (Clarke 1970, as Opercularella denticulata) to 4040 m deep (Vervoort 1966, as O. denticulata)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 61-62, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Clarke S. F. 1907. 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 \" Albatros \", from October 1904 to March 1905, Lieut. - Commander L. M. Garrett, U. S. N., commanding. VIII. The hydroids. Memoirs of the Museum of Comparative Zoology at Harvard College 35: 1 - 18.","Stechow E. 1913. Hydroidpolypen der japanischen Ostkuste. II. Teil: Campanularidae, Halecidae, Lafoeidae, Campanulinidae und Sertularidae, nebst Erganzungen zu den Athecata und Plumularidae. Abhandlungen der Koniglich Bayerischen Akademie der Wissenschaften, Supplementband zu den Abhandlungen der Mathematisch-naturwissenschaftlichen Klasse 3 (2): 1 - 162. https: // doi. org / 10.5962 / bhl. title. 11621","Vervoort W. 1966. Bathyal and abyssal hydroids. Galathea Report. Scientific Results of the Danish Deep-Sea Expedition, 1950 - 1952 8: 97 - 173.","Leloup E. 1974. Hydropolypes calyptoblastiques du Chili. Report no. 48 of the Lund University Chile Expedition 1948 - 1949. Sarsia 55: 1 - 62. https: // doi. org / 10.1080 / 00364827.1974.10411252","Schuchert P. 2003. Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to the Kei Islands. Steenstrupia 27 (2): 137 - 256.","Calder D. R. 2012. On a collection of hydroids (Cnidaria, Hydrozoa, Hydroidolina) from the west coast of Sweden, with a checklist of species from the region. Zootaxa 3171 (1): 1 - 77. https: // doi. org / 10.11646 / zootaxa. 3171.1.1"]}

Zygophylax sp. Fig. 3A–C; Table 2 Zygophylax ? biarmata – Millard 1958: 176–177, fig. 4a; 1975: 193, fig. 63c. Material examined SOUTH ATLANTIC OCEAN • 29 colonies, 16–61 mm high (1 growing on ghost fishing net), without coppiniae; Valdivia Seamount, stn BT12; 24°49′01″–24°47′38″ S, 6°24′40″–6°25′26″ E; 887– 886 m depth; 7 Feb. 2015;SEAFO-2015 leg.; SEAFO-2015-40192, SEAFO-2015-40282, SEAFO-2015-40432, SEAFO-2015-40492, SEAFO-2015-40767, SEAFO-2015-40811, SEAFO-2015-40827, LZM-UV slide R. 580. Description Colonies branched, stems erect, with a main primary tube surrounded by many secondary tubes, grading to monosiphonic distally. Lateral hydrocladia, originating from the primary tube, monosiphonic, forming an angle of 45° in all directions around the stem, always with an axillary hydrotheca. Some branches are occasionally branched once (secondary hydrocladia). The existence of internodes in both the stem and branches was not observed. Main stem and branches with the same structure and provided with alternately disposed hydrothecal apophyses, slightly directed to the ‘frontal’ side of the colony (Fig. 3B). Some isolated apophyses and hydrothecae were also observed arising from secondary tubes. Hydrothecae slightly shifted frontally, long, tubular, with the adcauline wall convex and the abcauline wall almost straight; basal part tapering below into a short pedicel, separated from hydrotheca by a slightly oblique, thin diaphragm; rim smooth, circular and slightly everted; renovations of the hydrothecal rim common and usually multiple; diaphragm occasionally renovated as well. Nematothecae inserting on small apophyses, usually one on each side of hydrotheca, but when lost, only a circular depression, corresponding to their origin, could be observed; tubular, with short, spherical pedicel; rim smooth, circular, slightly everted; renovations absent (Fig. 3C). Variabillity In one colony we found one hydrocladium that was polysiphonic at its basal part and distally monosiphonic. Remarks Our material clearly resembles Zygophylax biarmata Billard, 1905, but the hydrothecae are larger and, in addition, the arrangement of branches in all directions around the stem makes it easy to differentiate between species, as Z. biarmata presents branches that are arranged in the same plane as the main stem. Among all species of Zygophylax reported from West Africa, only one, Z. parabiarmata Vervoort, 2006, shows the lateral branches arranged in several planes, but in this case hydrothecae are arranged in different planes as well, whereas in Zygophylax sp. hydrothecae are almost in the same plane. Moreover, in Zygophylax sp. hydrothecae are longer and narrower than in Z. parabiarmata. Nevertheless, the material studied here agrees with that described by Millard (1958, 1975) as Zygophylax ? biarmata (not Z. biarmata Billard, 1905, see Ramil & Vervoort 1992: 60–65) in both measurements and the irregular disposition of the lateral branches around the stem, and the occasional presence of hydrothecae on secondary tubes. Consequently, we consider that all belong to the same species, but the absence of coppinia prevents us from assigning this material to a new species. Distribution This species has previously been recorded from off Natal, South Africa (Millard 1958, 1975, as Zygophylax ? biarmata), at depths of 164 to 333 m., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 57-59, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Millard N. A. H. 1958. Hydrozoa from the coasts of Natal and Portuguese East Africa. Part I. Calyptoblastea. Annals of the South African Museum 44 (5): 165 - 226.","Vervoort W. 2006. Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania- II expeditions of the National Museum of Natural History, Leiden, The Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden 80 (1): 181 - 318.","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Clarke S. F. 1907. 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 \" Albatros \", from October 1904 to March 1905, Lieut. - Commander L. M. Garrett, U. S. N., commanding. VIII. The hydroids. Memoirs of the Museum of Comparative Zoology at Harvard College 35: 1 - 18.","Stechow E. 1923. Uber Hydroiden der Deutschen Tiefsee-Expedition, nebst Bemerkungen uber einige andre Formen. Zoologischer Anzeiger 53 (9 - 10): 223 - 236."]}

Coryne pusilla Gaertner, 1774 Coryne pusilla Gaertner, 1774: 40–41, pl. 4 fig. 8. Coryne pusilla – Millard 1975: 51–52, fig. 19f–g. — Schuchert 2001b: 776–780, fig. 14a–b; 2012: 134–135, fig. 142. Material examined SOUTH ATLANTIC OCEAN • 1 colony, with sporosacs; Vema Seamount, stn BT5; 31°37′16″– 31°36′58″S,8°22′37″–8°23′06″E; 71–94m depth; 31Jan.2015;SEAFO-2015leg.; SEAFO-2015-40942 • 1 colony, with sporosacs, growing on sponge; Vema Seamount, stn Dive 5; 91 – 42 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40191. Remarks Molecular studies carried out by Schuchert (2005) to explore species boundaries within the genus Coryne found that populations identified as Coryne pusilla from the Mediterranean, Japan and Korea are genetically different from the Northeast Atlantic ones. Based on these results, Schuchert (2005, 2010) indicated that C. pusilla appears to be a species complex, an opinion also shared by Calder (2017). The material examined here is scarce and prevents us from giving a detailed description of the species. Nevertheless, we want to highlight that we found two size-classes of stenoteles: small (8.2–10.3× 4.1– 5.5 µm) and large (15.1–17.6 × 10.3–11.8 µm) ones. These measurements concur with those obtained by Millard (1975) from South African material, but they are clearly inferior to those reported from East and West Atlantic populations (see Schuchert 2001b and Calder 2017, respectively). These data suggest that the Southeast Atlantic populations of C. pusilla could also represent a different species. Distribution Coryne pusilla is considered as a circumglobal species, although the records from Madagascar and Kerguelen Islands (Millard 1975) and those from the Pacific Ocean (Millard 1975; Schuchert 2005, 2012) are considered as uncertain. It was reported from South Africa by Millard (1975). Its bathymetric range extends from the intertidal level to 100 m depth (Hirohito 1988)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 52, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Gaertner J. 1774. Zoophyta. In: Pallas P. S. (ed.) Spicilega zoologica quibus novae imprimus et obscurae animalium species. August Lange, Berolini.","Schuchert P. 2001 b. Survey of the family Corynidae (Cnidaria, Hydrozoa). Revue suisse de Zoologie 108: 739 - 878. https: // doi. org / 10.5962 / bhl. part. 80165","Schuchert P. 2005. Taxonomic revision and systematic notes on some Halecium species (Cnidaria, Hydrozoa). Journal of Natural History 39 (8): 607 - 639. https: // doi. org / 10.1080 / 00222930400001319","Schuchert P. 2010. The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Capitata Part 2. Revue suisse de Zoologie 117 (3): 337 - 555. https: // doi. org / 10.5962 / bhl. part. 117793","Calder D. R. 2017. Additions to the hydroids (Cnidaria, Hydrozoa) of the Bay of Fundy, northeastern North America, with a checklist of species reported from the region. Zootaxa 4256 (1): 1 - 86. https: // doi. org / 10.11646 / zootaxa. 4256.1.1","Schuchert P. 2012. North-West European Athecate Hydroids and their Medusae. In: Crothers J. H. & Haywars P. J. (eds) Synopses of the British Fauna (New Series) 59. Field Studies Council, London.","Hirohito Emperor of Japan. 1988. The Hydroids of Sagami Bay Collected by His Majesty the Emperor of Japan. Publications of the Biological Laboratory Imperial Household, Tokyo."]}

Turritopsis sp. Turritopsis sp. – Gil 2017: 37–41, fig. 6a. — Gil et al. 2020: 7–8, fig. 2a. Material examined SOUTH ATLANTIC OCEAN • 3 colonies, up to 6 mm high, without gonophores; Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40072; SEAFO-2015-40093, SEAFO-2015-40273 • 2 colonies, without gonophores (1 growing on ascidian and 1 on a gorgonian); Vema Seamount, stn Dive 4; 91–95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40134, SEAFO-2015-40631. Distribution Turritopsis sp. was collected from depths of 18 to 1581 m at several localities stretching from Western Sahara to Gabon (Gil 2017)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 53, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Gil M., Ramil F. & Ansin Agis J. 2020. Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds. Zootaxa 4878 (3): 412 - 466. https: // doi. org / 10.11646 / zootaxa. 4878.3.2"]}

Obelia dichotoma (Linnaeus, 1758) Sertularia dichotoma Linnaeus, 1758: 812. Laomedea (Obelia) dichotoma – Vervoort 1959: 315– 316. Obelia dichotoma – Millard 1975: 229–230, fig. 75a–b. — Ramil & Vervoort 1992: 243–244, fig. 68c. — Cornelius 1995: 296–300, fig. 69. Material examined SOUTH ATLANTIC OCEAN • 2 colonies, up to 19 mm high, without gonothecae; Vema Seamount, stn Dive 4; 91–95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40020, SEAFO-2015-40131. Distribution Obelia dichotoma is a well-known species with a nearly cosmopolitan distribution (Cornelius 1995); it is absent from Arctic and Antarctic waters (Peña Cantero & García Carrascosa 2002). In the Southeast Atlantic, it was reported from Angola (Vervoort 1959, as Laomedea (Obelia) dichotoma) and South Africa (Millard 1975). Its bathymetric distribution ranges from the intertidal (Cornelius 1995) to 540 m (Vervoort 2006)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 65-66, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Linnaeus C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. L. Salvius, Stockholm. https: // doi. org / 10.5962 / bhl. title. 542","Vervoort W. 1959. The Hydroida of the tropical west coast of Africa. Atlantide-Report: Scientific Results of the Danish Expedition to the Coasts of Tropical West Africa 5: 211 - 325.","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Cornelius P. F. S. 1995. North-West European Thecate Hydroids and their Medusae. Part 2. Sertulariidae to Campanulariidae. In: Barnes R. S. K. & Crothers J. H. (eds) Synopses of the British Fauna (New Series) 50. Field Studies Council, London.","Pena Cantero A. L. & Garcia Carrascosa A. M. 2002. The benthic hydroid fauna of the Chafarinas Islands (Alboran Sea, western Mediterranean). Zoologische Verhandelingen, Leiden 337: 1 - 180.","Vervoort W. 2006. Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania- II expeditions of the National Museum of Natural History, Leiden, The Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden 80 (1): 181 - 318."]}

Monostaechoides providentiae (Jarvis, 1922) gen. et comb. nov. Figs 5–6, 7A–B; Table 11 Plumularia providentiae Jarvis, 1922: 347–348, pl. 26 fig. 21. Antennella quadriaurita – Millard 1966: 492–493. — Calder 1997: 27–29, fig. 6 (not Antennella quadriaurita Ritchie, 1909). Material examined SOUTH ATLANTIC OCEAN • 3 colonies, 19–23 mm high, on sponge (1 with gonothecae); Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40063, LZM-UV slide R. 576 • 4 colonies, 5–7 mm high (1 colony, growing on algae, with gonothecae); Vema Seamount, stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″– 8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40227, SEAFO-2015-40497, SEAFO-2015-40768, LZM-UV slide R. 581. Description Hydrorhiza composed of a cluster of perisarcal tubes covered by a sponge growing on old gorgonian axis. In some cases, isolated hydrocladia are born directly on the hydrorhiza but, in most cases, several monosiphonic primary hydrocladia arise in tufts from a short, polysiphonic axis composed by several entangled stolons protruding from the sponge. The basal part of the primary hydrocladium is composed of one to five internodes separated by straight nodes, provided with a variable number of scattered nematothecae separated from the remainder of hydrocladium by an oblique node. This part is formed by a regular succession of hydrothecate and ahydrothecate internodes, delimited by alternating oblique and straight nodes; hydrothecate internodes with proximally oblique and distally straight nodes; ahydrothecate internodes with a reversed position of nodes (Figs 5E, 6C, 7B). Almost all primary hydrocladia carry lateral ramifications randomly disposed, always originating from their posterior side. In most cases, the subsidiary hydrocladia arise from the distal end of ahydrothecate internodes, just on the back side of the oblique nodes within the heteromerous part of the colony (Fig. 6A); occasionally, some ramifications are found on the basal part of primary hydrocladia (Figs 5F–G, 7A). All subsidiary hydrocladia (i.e., of the second, third and even fourth order) are born on small apophyses and are composed of a basal ahydrothecate internode of varied length carrying between one and four nematothecae (Figs 6A, D, 7A), followed by a regular succession of hydrothecate and ahydrothecate internodes with the same structure as the primary hydrocladia. Usually, all subsidiary hydrocladia originating from the same hydrocladium are directed to the same side in a linear succession, but irregularities also occur. Hydrothecate internodes with one hydrotheca and five nematothecae: one mesial inferior and two pairs of laterals. Hydrotheca cup-shaped, widening towards rim; adcauline wall adnate for about half its length; abcauline wall straight; hydrothecal rim circular, even and slightly everted. Mesial nematothecae not reaching hydrothecal base. Two pairs of lateral nematothecae; first pair borne on well-developed apophyses adpressed to the hydrothecal wall, and as long as the nematothecae proper, the latter reaching the hydrothecal rim; second pair small, inserted on bases of apophyses (Fig. 5D). Ahydrothecate internodes usually with two frontal nematothecae in a row, although the number may vary between one and three. All nematothecae bithalamic, movable and conical, with adcauline wall of distal chamber scooped. Colonies monoecious; gonothecae of both sexes found on same hydrocladia, arising from below the hydrothecal bases, just above the mesial nematothecae (Figs 6A–B, 7B). Male gonotheca small, sackshaped, with small and circular aperture located at the rounded top, basal part slightly curved and carrying one nematotheca, and narrowing into a short pedicel composed of one internode. Female gonotheca pear-shaped, rather curved, with a distal, slightly tilted, circular aperture, closed by lid; basally provided with two nematothecae and narrowing into a two-segmented pedicel. Variability In some hydrocladia, the regeneration processes when ahydrothecate internodes are damaged result in two ahydrothecate internodes, each one with one or two nematothecae, between two consecutive hydrothecate internodes. We have also observed a subsidiary hydrocladium originating from the back side of a hydrothecate internode (Fig. 6D), but this type of ramification is exceptional and probably related to regeneration processes. Remarks Our material agrees with the main features described by Jarvis (1922) as Plumularia providentiae. In both cases the colonies are ramified, with the subsidiary hydrocladia originating from the back side of a true axis (or hydrocladia) shifted on to one side, but that does not adopt the shape of a scorpioid sympodium. Moreover, the morphology of hydrothecae and the number and arrangement of the nematothecae are also similar. The main difference is found in the presence, in our colonies, of subsidiary hydrocladia originating from the basal part of some primary hydrocladia; however, this is an occasional feature and not the norm. Moreover, Jarvis (1922) described P. providentiae with homomerously segmented hydrocladia, but in our colonies the segmentation is heteromerous. Nevertheless, the existence of intermediate ahydrothecate internodes is clearly visible only in subsidiary and younger hydrocladia. In older parts of the colony, and mainly in primary hydrocladia, the perisarc of the wall is thick, masking the heteromerous segmentation. In our opinion, these differences do not justify the description of a new species and, therefore, we identify our material as Monostaechoides providentiae (Jarvis, 1922) gen. et comb. nov. In addition, the material described from the Vema Seamount by Millard (1966) as Antennella quadriaurita (Ritchie, 1909), with hydrocladia clustered together basally and ramified following the same pattern as our colonies, also belongs to this species. Colonies found in Bermuda with a similar morphology and with the same ramification pattern were described by Calder (1997) as A. quadriaurita (see Calder 1997: 28, fig. 6a). That material, excluded from A. quadriaurita by Galea & Ferry (2015), is also included here in M. providentiae gen. et comb. nov. Differences between M. providentiae gen. et comb. nov. and M. bertoti gen. et comb. nov. were discussed by Galea & Ferry (2015), and refer to the ramification pattern, with hydrocladia more or less alternately arranged in M. bertoti gen. et comb. nov., and a different number of nematothecae on both cauline and cladial internodes. Distribution This species has been reported from Providence Atoll, the Seychelles (Jarvis 1922, as Plumularia providentiae), Vema Seamount (Millard 1966; Berrisford 1969, both as A. quadriaurita) and Bermuda (Calder 1997, as A. quadriaurita) in depths from 42 to 85 m., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 73-78, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Jarvis F. E. 1922. The hydroids from the Chagos, Seychelles and other islands and from the coasts of British East Africa and Zanzibar. Transactions of the Royal Society of London, Zoology 18 (1): 331 - 360. https: // doi. org / 10.1111 / j. 1096 - 3642.1922. tb 00553. x","Millard N. A. H. 1966. Hydroids of the Vema Seamount. Annals of the South African Museum 48: 489 - 496.","Calder D. R. 1997. Shallow-water hydroids of Bermuda: superfamily Plumularioidea. Life Sciences Contributions of the Royal Ontario Museum 161: 1 - 85.","Ritchie J. 1909. New species and varieties of Hydroida Thecata from Andaman Island. The Annals and Magazine of Natural History, Series 8 3: 524 - 528.","Galea H. R. & Ferry R. 2015. Notes on some hydroids (Cnidaria) from Martinique, with descriptions of five new species. Revue suisse de Zoologie 122 (2): 213 - 246. https: // doi. org / 10.5281 / zenodo. 29998","Berrisford C. D. 1969. Biology and zoogeography of the Vema Seamount: a report on the first biological expedition made on the seamount. Transactions of the Royal Society of South Africa 38: 387 - 398. https: // doi. org / 10.1080 / 00359196909519099"]}

Halecium tenellum Hincks, 1861 Halecium tenellum Hincks, 1861: 252, pl. 6 figs 1–4. Halecium tenellum – Cornelius 1975: 409–411, fig. 12. — Ramil & Vervoort 1992: 90–91, fig. 21f–g. Material examined SOUTH ATLANTIC OCEAN • 7 colonies, without gonothecae (1 growing on Zygophylax sp., 1 on bivalve shell, and 5 on ghost fishing net); Valdivia Seamount, stn BT12; 24°49′01″–24°47′38″ S, 6°24′40″–6°25′26″ E; 887– 886 m depth; 7 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40282, SEAFO-2015-40402, SEAFO-2015-40762, SEAFO-2015-40797, SEAFO-2015-40811, SEAFO- 2015-40850, SEAFO-2015-40852. Distribution Halecium tenellum is a nearly cosmopolitan species (Cornelius 1975), with records from all oceans, including polar waters, although some identifications from high latitudes in the North Atlantic proved to be erroneous (Calder 1991; Schuchert 2005). Reported from South Africa by Millard (1975). Its bathymetric range extends from the intertidal zone to 1200 m (Peña Cantero & García Carrascosa 2002)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 66-67, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Hincks T. 1861. A catalogue of the Zoophytes of South Devon and South Cornwall. The Annals and Magazine of Natural History (3) 8: 152 - 161, 251 - 262, 290 - 297. https: // doi. org / 10.1080 / 00222936108697420","Cornelius P. F. S. 1975. A revision of the species of Lafoeidae and Haleciidae (Coelenterata: Hydroida) recorded from Britain and nearby seas. Bulletin of the British Museum Natural History. Zoology 28: 375 - 426. https: // doi. org / 10.5962 / p. 271711","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Calder D. R. 1991. Shallow-water hydroids of Bermuda. The Thecatae, exclusive of Plumularioidea. Life Sciences Contributions of the Royal Ontario Museum 154: 1 - 140.","Schuchert P. 2005. Taxonomic revision and systematic notes on some Halecium species (Cnidaria, Hydrozoa). Journal of Natural History 39 (8): 607 - 639. https: // doi. org / 10.1080 / 00222930400001319","Pena Cantero A. L. & Garcia Carrascosa A. M. 2002. The benthic hydroid fauna of the Chafarinas Islands (Alboran Sea, western Mediterranean). Zoologische Verhandelingen, Leiden 337: 1 - 180."]}

Stegolaria geniculata (Allman, 1888) Cryptolaria geniculata Allman, 1888: 41, pl. 20 figs 1, 1a–b. Stegolaria geniculata – Ramil & Vervoort 1992: 32–34, fig. 4c–e. — Watson & Vervoort 2001: 154, fig. 2a–d. Material examined SOUTH ATLANTIC OCEAN • 1 colony, 10 mm high, without gonothecae; Vema Seamount, stn Dive 3; 71–935 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40648 • 54 colonies, 15–62 mm high (2 colonies growing on bivalves, 2 on ghost fishing net and 2 on ropes), 21 colonies, with gonothecae; Valdivia Seamount, stn BT12; 24°49′01″–24°47′38″ S, 6°24′40″–6°25′26″ E; 887– 886 m depth; 7 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40220, SEAFO-2015-40342, SEAFO-2015-40462, SEAFO-2015-40582, SEAFO-2015-40707, SEAFO-2015-40792, SEAFO-2015-40811, SEAFO-2015- 40822, SEAFO-2015-40850, SEAFO-2015-40852. Distribution A circumglobal species (Ramil & Vervoort 1992), widely distributed in deep waters of the Atlantic Ocean (Vervoort 2006). Its bathymetric distribution extends between 300 and 1727 m (Stepanjants 2012; Gil 2017)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 60, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Allman G. J. 1888. Report on the Hydroida dredged by H. M. S. Challenger during the years 1873 - 76. Part II. The Tubularinae, Corymorphinae, Campanularinae, Sertularinae and Thalamorphora. Report on the Scientific Results of the Voyage of H. M. S. Challenger, Zoology 23 (70): 1 - 90.","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Watson J. E. & Vervoort W. 2001. The hydroid fauna of Tasmanian seamounts. Zoologische Verhandelingen, Leiden 334: 151 - 188.","Vervoort W. 2006. Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania- II expeditions of the National Museum of Natural History, Leiden, The Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden 80 (1): 181 - 318.","Stepanjants S. D. 2012. Deep-water Hydrozoa (Cnidaria: Medusozoa) in the Sea of Japan, collected during the 51 st cruise of R / V Akademik M. A. Lavrentyev, with description Opercularella angelikae, sp. nov. Deep Sea Research Part II: Topical Studies in Oceanography 86 - 87: 231 - 237. https: // doi. org / 10.1016 / j. dsr 2.2012.08.014"]}

Leuckartiara octona (Fleming, 1823) Geryonia octona Fleming, 1823: 298. Leuckartiara octona – Millard 1975: 123–125, fig. 41a–d. — Schuchert 2012: 251–252, fig. 232. Material examined SOUTH ATLANTIC OCEAN • 1 colony, without gonophores; Valdivia Seamount, stn GRAB14B; 26°15′38″ S, 6°16′37″ E; 451 m depth; 5 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40452. Distribution Circumglobal in subtropical and temperate waters. In the eastern Atlantic, it has been reported from the Arctic Seas (Kramp 1938) to South Africa (Millard 1975). Its bathymetric range extends from the intertidal (Millard 1975) to depths of 418 m (Gil & Ramil 2017) and 451 m (this paper)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 55, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Fleming J. 1823. Gleanings of natural history, gathered on the coast of Scotland during a voyage in 1821. The Edinburgh Philosophical Journal 8: 294 - 303.","Schuchert P. 2012. North-West European Athecate Hydroids and their Medusae. In: Crothers J. H. & Haywars P. J. (eds) Synopses of the British Fauna (New Series) 59. Field Studies Council, London.","Kramp P. L. 1938. Marine Hydrozoa. Hydroida. The Zoology of Iceland 2: 1 - 82.","Gil M. & Ramil F. 2017. Hydrozoans from Mauritanian deep-waters. In: Ramos A., Ramil F. & Sanz J. L. (eds) Deep-Sea Ecosystems off Mauritania: 419 - 444. Springer Netherlands, Dordrecht. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11"]}

Campanularia hincksii Alder, 1856 Campanularia hincksii Alder, 1856: 360–361, pl. 13 fig. 9. Campanularia hincksii – Ramil & Vervoort 1992: 233–235, fig. 66. — Cornelius 1995: 229–231, fig. 52. Material examined SOUTH ATLANTIC OCEAN • 9 colonies, 0.5–17 mm high (2 growing on antipatharians, 1 on sponge, 1 on Sertularella arbuscula, 1 on Sertularella striata, 1 on Turritopsis sp.), all without gonothecae; Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40003, SEAFO-2015-40093, SEAFO-2015-40123, SEAFO-2015-40153, SEAFO-2015-40213, SEAFO-2015-40243, SEAFO-2015-40273, SEAFO-2015- 40444, SEAFO-2015-40972 • 5 colonies, 8–12 mm high (2 with gonothecae); stn Dive 3; 71–935 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40132, SEAFO-2015-40257, SEAFO-2015-40678 • 2 colonies, without gonothecae (1 growing on Amphisbetia distans); Vema Seamount, stn Dive 4; 91– 95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40131, SEAFO-2015-40977 • 1 colony, growing on ghost fishing net, without gonothecae; Valdivia Seamount, stn BT12; 24°49′01″–24°47′38″ S, 6°24′40″–6°25′26″ E; 887– 886 m depth, 7 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40850. Distribution Campanularia hincksii is a circumglobal species, recorded in the eastern Atlantic from Iceland to South Africa (Peña Cantero & García Carrascosa 2002). Its bathymetric distribution extends from the tidal level to a depth of 1200 m (Peña Cantero & García Carrascosa 2002; Leloup 1940)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 62-63, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Alder J. 1856. A notice of some new genera and species of British hydroid zoophytes. The Annals and Magazine of Natural History series 2 18: 353 - 362. https: // doi. org / 10.1080 / 00222935608697652","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Cornelius P. F. S. 1995. North-West European Thecate Hydroids and their Medusae. Part 2. Sertulariidae to Campanulariidae. In: Barnes R. S. K. & Crothers J. H. (eds) Synopses of the British Fauna (New Series) 50. Field Studies Council, London.","Stechow E. 1923. Uber Hydroiden der Deutschen Tiefsee-Expedition, nebst Bemerkungen uber einige andre Formen. Zoologischer Anzeiger 53 (9 - 10): 223 - 236.","Pena Cantero A. L. & Garcia Carrascosa A. M. 2002. The benthic hydroid fauna of the Chafarinas Islands (Alboran Sea, western Mediterranean). Zoologische Verhandelingen, Leiden 337: 1 - 180.","Leloup E. 1940. Hydropolypes provenant des croisieres du Prince Albert Ier de Monaco. Resultats des Campagnes scientifiques du Prince Albert I de Monaco 104: 1 - 38."]}

Filellum sp. Fig. 2F; Table 1 Material examined SOUTH ATLANTIC OCEAN • 2 colonies (1 growing on an antipatharian, 1 on Sertularella patagonica), no coppinia; Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40003, SEAFO-2015-40033 • 4 colonies (3 growing on Campanularia hincksii, 1 on a bryozoan), no coppinia; Vema Seamount, stn Dive 3; 71–935 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40132, SEAFO-2015-40257, SEAFO-2015-40921 • 1 colony, growing on Amphisbetia distans, no coppinia; Vema Seamount, stn Dive 4; 91–95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40661. Description Stolonal colonies arising from a filiform hydrorhiza creeping on other hydroids and a bryozoan. Hydrorhizal stolons give rise to small, tubular hydrothecae adnate for ca half their length; adnate part parallel to hydrorhiza, upper, free part provided with numerous and very faint striations on abcaulinar side, and bent upwards from hydrorhiza at an angle between 45° and 90°, although only occasionally perpendicular to the adnate part; aperture circular, rim even, only slightly everted; renovations have not been observed. Cnidome: two size classes of nematocysts, with small (10–12.5× 5–7.5 µm) and large (15–17.5 × 7.5–10 µm). Coppinia absent. Remarks The shape of the hydrothecae in the colonies studied herein resembles those of Filellum serratum (Clarke, 1879), Filellum antarcticum (Hartlaub, 1904) and Filellum magnificum Peña Cantero, Svoboda & Vervoort, 2004, due to the presence of numerous transversal striations of the adnate part. Nevertheless, the measurements of both hydrothecae and nematocysts do not match with those of the species mentioned above. In our material, the hydrothecae are smaller and the nematocysts larger than those of F. serratum, F. antarticum and F. magnificum. Based on these differences, we considered this material to be a different species, but the absence of coppinia prevents us from establishing a more accurate identification., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 56, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Pena Cantero A. L., Svoboda A. & Vervoort W. 2004. Antarctic hydroids (Cnidaria, Hydrozoa) of the families Campanulinidae, Lafoeidae and Campanulariidae from recent Antarctic expeditions with R. V. Polarstern, with the description of a new species. Journal of Natural History 28: 2269 - 2303. https: // doi. org / 10.1080 / 00222930310001647361"]}

Modeeria rotunda (Quoy & Gaimard, 1827) Dianeae rotunda Quoy & Gaimard, 1827: 181–182, pl. 6a figs 1–2. Modeeria rotunda – Millard 1975: 137–138, fig. 45a. — Ramil & Vervoort 1992: 29–32, fig. 4a–b. Material examined SOUTH ATLANTIC OCEAN • 1 colony, growing on Eudendrium ramosum, without gonothecae; Vema Seamount, stn Dive 3; 71–935 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40708. Distribution Modeeria rotunda is a cosmopolitan species (Ramil & Vervoort 1992; Vervoort 2006). In the Southeast Atlantic, it was reported from Namibia (Gili et al. 1989) and also from the east coast of South Africa to Mozambique (Millard 1975). Its bathymetric distribution extends from 0.5 to 1575 m (Gil 2017)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 59, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Quoy J. R. C. & Gaimard J. P. 1827. Observations zoologiques faites a bord de l' Astrolabe, en mai 1826, dans le Detroit de Gibraltar. Annales des Sciences naturelles, Zoologie 10: 5 - 21, 172 - 193, 225 - 239.","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Vervoort W. 2006. Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania- II expeditions of the National Museum of Natural History, Leiden, The Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden 80 (1): 181 - 318.","Gili J. M., Vervoort W. & Pages F. 1989. Hydroids from the West African coast: Guinea Bissau, Namibia and South Africa. Scientia Marina 53 (1): 67 - 112."]}

Sertularella arbuscula (Lamouroux, 1816) Table 9 Sertularia arbuscula Lamouroux, 1816: 191–192, pl. 5 fig. 4. Sertularella crassipes Allman, 1886: 133–134, pl. 8 figs 4–5. Sertularella arbuscula – Millard 1975: 281–282, fig. 91j–l. Material examined SOUTH ATLANTIC OCEAN • 2 colonies, up to 31 mm high, without gonothecae; Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40093, SEAFO-2015-40123 • 2 colonies, up to 40 mm high growing on algae, without gonothecae; Vema Seamount, stn BT5; 31°37′16″–31°36′58″ S, 8°22′37″–8°23′06″ E; 71–94 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40527, SEAFO-2015-40768, LZM-UV slide R. 588 • 1 colony, 30 mm high, growing on bryozoan, with gonothecae; Valdivia Seamount, stn PT10; 25°36′54″–25°37′26″ S, 6°12′40″–6°11′31″ E; 476–707 m depth; 5 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40414. Distribution This species has been previously recorded from the Australasian Seas, Indian Ocean, South Africa and Vema Seamount, from the littoral zone to a depth of 219 m (Millard 1966, 1975). Our records from Valdivia Bank, between 476 and 707 m, represent the deepest known localities for this species., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 69, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Lamouroux J. V. F. 1816. Histoire des Polypiers coralligenes flexibles, vulgairement nommes Zoophytes. F. Poisson, Caen. https: // doi. org / 10.5962 / bhl. title. 11172","Allman G. J. 1886. Description of Australian, Cape, and other Hydroida, mostly new, from the collection of Miss H. Gatty. Journal of the Linnean Society of London, Zoology 19: 132 - 161. https: // doi. org / 10.1111 / j. 1096 - 3642.1885. tb 01994. x"]}

Plumularia setacea (Linnaeus, 1758) Sertularia setacea Linnaeus, 1758: 813. Plumularia setacea – Ramil & Vervoort 1992: 191–193, fig. 47f–i. — Ansín Agís et al. 2001: 238–245, fig. 91. Material examined SOUTH ATLANTIC OCEAN • 1 colony, without gonothecae; Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40924 • 2 colonies (1 with gonothecae); Vema Seamount, stn Dive 4; 91–95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40050, SEAFO-2015-40131. Distribution Circumglobal, with a bathymetric range of 0 to 1517 m (Ansín Agís et al. 2001; Gil 2017). In the Southeast Atlantic, it was reported from Angola (Broch 1914; Bouillon et al. 1995), Namibia (Broch 1914; Gili et al. 1989), Vema Seamount (Millard 1966) and South Africa (Millard 1975)., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 82, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Linnaeus C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. L. Salvius, Stockholm. https: // doi. org / 10.5962 / bhl. title. 542","Ramil F. & Vervoort W. 1992. Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden 277: 1 - 262.","Ansin Agis J., Ramil F. & Vervoort W. 2001. Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, The Netherlands. Zoologische Verhandelingen, Leiden 333: 1 - 268.","Broch H. 1914. Hydrozoa benthonica. In: Michaelsen W. (ed.) Beitrage zur Kenntnis der Meeresfauna Westafrikas. Volume 1: 19 - 50. L. Friederichsen & Co., Hamburg.","Bouillon J., Massin C. & Kresevic R. 1995. Hydroidomedusae de l'Institut royal des Sciences naturelles de Belgique. Documents de Travail de l'Institut royal des Sciences naturelles de Belgique 78: 3 - 106.","Gili J. M., Vervoort W. & Pages F. 1989. Hydroids from the West African coast: Guinea Bissau, Namibia and South Africa. Scientia Marina 53 (1): 67 - 112.","Millard N. A. H. 1966. Hydroids of the Vema Seamount. Annals of the South African Museum 48: 489 - 496."]}

Clytia gigantea (Hincks, 1866) Fig. 4A; Table 6 Campanularia gigantea Hincks, 1866: 297. Clytia gigantea – Calder 2012: 46–47, figs 46–47. — Peña Cantero & Horton 2017: 13, fig. 5a–b. Clytia sp. – Ramil 1988: 254–256, pl. XVII. Material examined SOUTH ATLANTIC OCEAN • 5 colonies, up to 13 mm high (2 growing on a ghost fishing net, 1 on Stegolaria geniculata), no gonothecae; Valdivia Seamount, stn BT12; 24°49′01″–24°47′38″ S, 6°24′40″–6°25′26″ E; 887– 886 m depth; 7 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40552, SEAFO-2015-40582, SEAFO-2015-40811, SEAFO-2015-40852, SEAFO-2015-40857, LZM-UV slide R. 579. Remarks Despite the fact that this species is currently included in the synonymy of Clytia hemisphaerica (Linnaeus, 1767) (Schuchert 2020), we agree with Calder (2012) who considers C. gigantea as a valid species, due to the comparatively larger size of its hydrothecae, provided with linguiform cusps, an opinion that was also later shared by Peña Cantero & Horton (2017). Moreover, Ramil (1988), in his study of the hydroids of Galicia (NW Spain), described this species as Clytia sp., apart from C. hemisphaerica, based on the same features highlighted by Calder (2012). Therefore, considering that both morphological features and measurements of our colonies coincide with those given by Ramil (1988), Calder (2012) and Peña Cantero & Horton (2017), we identify this material as C. gigantea. The material studied here also resembles C. joycei Calder, 2019 in the hydrothecal shape; however, C. joycei is a shallow-water species, growing on the seagrass Thalassia testudinum K.D. Koening, 1805 and develops minute, stolonal colonies with comparatively smaller hydrothecae. These features typically separate C. joycei from C. gigantea (Calder 2019). Distribution This species has been recorded from the boreal waters of the Northeast Atlantic (Calder 2012) to Galicia, NW Spain (Ramil 1988, as Clytia sp.) and also from Newfoundland to Cape Cod in the West Atlantic (Calder 2012). Its presence outside the Atlantic Ocean, including the Mediterranean Sea, is considered as doubtful by Calder (2012). The records from Chile (Leloup 1974; Galea et al. 2009) are based on misidentifications (Galea & Schories 2012). Its bathymetric distribution extends from 20 (Calder 2012) to 950 m (Peña Cantero & Horton 2017). Clytia gigantea is reported here for the first time from the South Atlantic, at Valdivia Seamount., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 63-65, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Hincks T. 1866. On new British Hydroida. The Annals and Magazine of Natural History (3) 18: 296 - 299. https: // doi. org / 10.1080 / 00222936608679646","Calder D. R. 2012. On a collection of hydroids (Cnidaria, Hydrozoa, Hydroidolina) from the west coast of Sweden, with a checklist of species from the region. Zootaxa 3171 (1): 1 - 77. https: // doi. org / 10.11646 / zootaxa. 3171.1.1","Pena Cantero A. L. & Horton T. 2017. Benthic hydroids (Cnidaria, Hydrozoa) from bathyal and abyssal depths of the Northeast Atlantic held in the modern Discovery Collections. Zootaxa 4347 (1): 1 - 30. https: // doi. org / 10.11646 / zootaxa. 4347.1.1","Ramil F. 1988. Hidrozoos de Galicia. PhD thesis, Universidade de Santiago de Compostela, Spain.","Schuchert P. 2020. World Hydrozoa Database. Available from http: // www. marinespecies. org / hydrozoa / [accessed 14 Jan. 2021].","Thompson d'Arcy W. 1879. On some new and rare hydroid zoophytes (Sertulariidae and Thuiariidae) from Australia and New Zealand. The Annals and Magazine of Natural History, Series 5 3 (14): 97 - 114. https: // doi. org / 10.1080 / 00222937908682487","Nutting C. C. 1904. American hydroids, Part II. The Sertulariidae. Bulletin of the United States National Museum 4 (2): 1 - 325.","Linnaeus C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. L. Salvius, Stockholm. https: // doi. org / 10.5962 / bhl. title. 542","d' Orbigny A. D. 1846. Zoophytes. In: Bertrand P. (ed.) Voyage dans l'Amerique meridionale (Le Bresil, La Republique orientale de l'Uruguay, La Republique argentine, La Patagonie, La Republique du Chili, La Republique de Bolivia, La Republique du Perou), execute pendant les annees 1826, 1827, 1828, 1829, 1830, 1831, 1832 et 1833. Zoophytes: Tome V, 4 e Partie. Bertrand, Paris and Levrault, Strasbourg. https: // doi. org / 10.5962 / bhl. title. 100771","Calder D. R. 2019. On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA. Zootaxa 4689 (1): 1 - 141. https: // doi. org / 10.11646 / zootaxa. 4689.1.1","Leloup E. 1974. Hydropolypes calyptoblastiques du Chili. Report no. 48 of the Lund University Chile Expedition 1948 - 1949. Sarsia 55: 1 - 62. https: // doi. org / 10.1080 / 00364827.1974.10411252","Galea H. R., Haussermann V. & Forsterra G. 2009. New additions to the hydroids (Cnidaria: Hydrozoa) from the fjords region of southern Chile. Zootaxa 2019 (1): 1 - 28. https: // doi. org / 10.11646 / zootaxa. 2019.1.1","Galea H. R. & Schories D. 2012. Some hydrozoans (Cnidaria) from Central Chile and the Strait of Magellan. Zootaxa 3296 (1): 19 - 67. https: // doi. org / 10.11646 / zootaxa. 3296.1.2"]}

Amphinema biscayana (Browne, 1907) Fig. 2A–E Bimeria biscayana Browne, 1907: 21–23, pl. 1 figs 4–5. Amphinema biscayana – Schuchert 2000: 415–417, fig. 3a–e; 2001a: 21–22, fig. 11a–d; 2007: 317–319, fig. 51. Material examined SOUTH ATLANTIC OCEAN • 3 colonies, 23–30 mm high (1 with medusa buds); Valdivia Seamount, stn BT12; 24°49′01″– 24°47′38″ S, 6°24′40″– 6°25′26″ E; 887– 886 m depth; 7 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40162, SEAFO-2015-40522. Description Colonies up to 20 mm high, polysiphonic in their basal parts, grading to monosiphonic distally; ramified, with thick main stem and branches; axial tube surrounded by numerous, comparatively thinner, auxiliary tubes running parallel to one another (Fig. 2B, D). Branches originating from auxiliary tubes, and not from the main tube. Polyps scattered along the main stem and branches, placed at the distal end of short pedicels originating from both the main and auxiliary tubes (Fig. 2C–E); basal parts of the polyps covered by a pseudohydrotheca, ending below the tentacles; column cylindrical, with an apical, conical hypostome, surrounded by a whorl of 15–16 filiform tentacles. Nematocysts: desmonemes (5.5–6 × 3.5– 5 µm) and asymmetric microbasic euryteles (6–8× 3.5–4 µm). Medusa buds given off from auxiliary tubes, far away from hydranths; almost rounded and enclosed in thin perisarcal envelope; four small bulbs are clearly differentiated distally (Fig. 2D). Remarks In our material, we have not observed the distal ramification of the main axis with lateral branches, as described by Schuchert (2001a). Nevertheless, other features, such as the origin of lateral branches from auxiliary tubes, the morphology and type of nematocysts, as well as their measurements, concur with observations made by Schuchert (2000, 2001a) and, consequently, we identified our material as A. biscayana. Distribution Amphinema biscayana has previously been reported from South Iceland (Schuchert 2000) and the Bay of Biscay (Browne 1907, as Bimeria biscayana). Its bathymetric distribution ranges from depths of 20 to 2076 m (Schuchert 2000, 2001b). Our discovery is the first record of this species for South Atlantic waters., Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on pages 53-55, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125, {"references":["Browne E. T. 1907. The Hydroida collected by the \" Huxley \" from the north side of the Bay of Biscay in August, 1906. Journal of the Marine Biological Association of the United Kingdom 8: 15 - 37. https: // doi. org / 10.1017 / S 002531540004371 X","Schuchert P. 2000. Hydrozoa (Cnidaria) of Iceland collected by the BIOICE programme. Sarsia 85: 411 - 438. https: // doi. org / 10.1080 / 00364827.2000.10414592","Schuchert P. 2001 a. Hydroids of Greenland and Iceland (Cnidaria, Hydrozoa). BioScience 53: 1 - 184.","Schuchert P. 2001 b. Survey of the family Corynidae (Cnidaria, Hydrozoa). Revue suisse de Zoologie 108: 739 - 878. https: // doi. org / 10.5962 / bhl. part. 80165"]}

Sertularella porcupine nom. nov. (Fig. 3E) Sertularella gayi var. robusta Allman, 1873: 186; Allman, 1874: 474, pl. LXVI, figs 3, 3A; Billard, 1906b: 185, fig. 9C. Sertularella gayi robusta: Ramil & Vervoort, 1992: 223–225, figs. 60B, 62A–C; Medel & Vervoort, 1998: 45–46, fig. 12; Calder & Vervoort, 1998: 39–41, fig. 19A–B. Material examined. MAURIT-0911, stn MUDR01, 16º08´24”N, 16º57´12”W, 488 m, 5-XII-2009: one hydrothecae growing on a bryozoan, no gonothecae. Etymology. The specific name porcupine refers the 1869 Expedition of the vessel H.M.S. “Porcupine”, in which the species was collected for the first time. Noun in apposition. Biology. This species has been found growing on coral fragments and gorgonians (Medel & Vervoort 1998) and on bryozoans, scleractinians and artificial substrata (Gil & Ramil 2017a). Fertile material has been found in May, June and November (Medel & Vervoort 1998). In our material, this species was epibiont on a bryozoan. Distribution. Sertularella porcupine nom. nov. is an East Atlantic species reported from the Shetland Islands to Madeira and the Atlantic coast of Morocco (Ramil & Vervoort 1992, as Sertularella gayi robusta Allman, 1873). In West Africa, it was collected from Morocco (Billard 1906b, as S. gayi var. elongata and S. gayi var. robusta; Ramil & Vervoort 1992, as S. gayi robusta), Mauritania (Gil & Ramil 2017a, as S. gayi robusta) and Cape Verde region (Medel & Vervoort 2000, as S. gayi robusta). Its bathymetric distribution ranges from 120 to 1003 m (Gil & Ramil 2017a; Calder & Vervoort 1998, both as S. gayi robusta). Our material was collected from a depth of 488 m. Remarks. The differences between S. gayi and Sertularella porcupine nom. nov. (= S. gayi robusta) were established by Ramil & Vervoort (1992), and they deal with the ramification pattern of the colonies, size of the hydrothecae and the morphology of gonothecal aperture. In Sertularella porcupine nom. nov. the ramification of the colony is more irregular with branches disposed all around of axis, the hydrothecae are bigger and the gonothecal aperture provided with three low cups versus two lips ins S. gayi. Research on the DNA barcode gene 16S mRNA within Sertulariidae conducted by Moura et al. (2011) suggested that S. gayi and S. porcupine nom. nov. (= S. gayi robusta) are different species, but the authors used the name ‘ Sertularella robusta ’ for the material collected from the deep waters of the Gulf of Cádiz; nevertheless, the binomen Sertularella robusta cannot be applied to Allman’s variety because it is an invalid junior homonym of Sertularella robusta Coughtrey, 1879, a different species mainly distributed in the Indo-Pacific region (Vervoort & Watson 2003). Another name applied to this species was Sertularella gayi var. elongata Billard, 1906b, included by Ramil & Vervoort (1992) in its synonym. The binomen Sertularella elongata is also an invalid junior homonym of Sertularella elongata Jäderholm, 1904 [= Antarctoscyphus elongatus (Jäderholm, 1904)]. In consequence, we propose Sertularella porcupine as a replacement name for this species.

Streptocaulus multiseptatus (Bale, 1915) Cladocarpia multisepatus Bale, 1915: 304���306, pl. 47 figs. 1���5. Cladocarpus multiseptatus: Alvarez Claudio, 1993: 221���224, fig. 38, Lam. XX; ��lvarez Claudio, 1995: 13���14, fig. 2.1; Bouillon et al., 2004: 124, fig. 65K. Cladocarpus cf. multiseptatus: Ramil & Vervoort, 1992: 109���111, fig. 27a. Streptocaulus multiseptatus: Ramil & Vervoort, 2008: 417���421, figs. 1���2. Material examined. MAURIT-0911, stn MUDR06, 17��40��22���N, 16��40��11���W, 435 m, 10-XII-2009: four colonies, without phylactocarps. Biology. Colonies of S. multiseptatus with phylactocarps and gonothecae have been found only in November (Ramil & Vervoort 2008). Our material was found on the cold-water coral mound barrier. Distribution. This species is known from Australia, Bay of Biscay, Alboran Sea and the Sahara coast; its bathymetric distribution ranges from 135 to 576 m (Ramil & Vervoort 2008). In West Africa, S. multiseptatus was reported in Western Sahara (Ramil & Vervoort 2008) and also in Mauritania (Gil & Ramil 2017a). Our material was collected from a depth of 435 m off Nouakchott, representing the southernmost record of the species in the Atlantic Ocean. Remarks. The material examined by us is consistent with the description of S. multiseptatus given by Ramil & Vervoort (2008) on the basis of material collected off the Sahara coast., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on page 432, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Bale, W. M. (1915) Report on the Hydroida collected in the Great Australian Bight and other localities. Part III. Fish. Zool. (biol) Biological Results of the Fishing Experiments Carried on by the F. I. S. \" Endeavour \", 1909 - 14, 3 (5), 304 - 307.","Alvarez Claudio, M. C. (1993) Hidrozoos bentonicos y Catalogo de Antozoos de la Plataforma y Talud Continentales de la costa central de Asturias. Tesis de Licenciatura, Universidad de Oviedo, Oviedo, Asturias, 458 pp.","Alvarez Claudio, M. C. (1995) Some records of the superfamily Plumularioidea L. Agassiz, 1862 (Cnidaria, Hydrozoa) from the Bay of Biscay. Miscel. lania Zoologica, 18, 9 - 20.","Bouillon, J., Medel, M. D., Pages, F., Gili, J. M., Boero, F. & Gravili, C. (2004) Fauna of the Mediterranean Hydrozoa. Scientia Marina, 68 (2), 5 - 438. https: // doi. org / 10.3989 / scimar. 2004.68 s 25","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Ramil, F. & Vervoort, W. (2008) Note on Streptocaulus multiseptatus (Bale, 1915) (Cnidaria: Leptolida: Aglaopheniidae), with the description of its gonosome. Zoologische Medelingen Leiden, 82, 417 - 422.","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11"]}

Lytocarpia myriophyllum (Linnaeus, 1758) Lytocarpia myriophyllum: Ramil & Vervoort, 1992: 137���143, figs. 35b���d, 36a���j; Ramil et al., 1998:19���23, figs. 9���12; Ans��n Ag��s et al., 2001: 88���99, figs. 40���45; Di Camillo et al., 2013: 778���784, figs. 2���5. Material examined. MAURIT-0911, stn MUDR02, 16��08��50���N, 16��57��01���W, 462 m, 5-XII-2009: one colony, no corbulae. Biology. Lytocarpia myriophyllum shows hydrorhizal adaptations to anchor the colony in soft bottoms (Ans��n Ag��s et al. 2001). Because of its capacity to create wide forests and stabilize sediments, it was defined as a habitat former and ecosystem engineer (Di Camillo et al. 2013). Fertile material has been reported from March to November (Ans��n Ag��s et al. 2001; Di Camillo et al. 2013). Our colony was collected on the cold-water coral mounds barrier but detached from substratum. Distribution. The geographical distribution of L. myriophyllum was reviewed by Ans��n Ag��s et al. (2001), who excluded the records of this species from the Pacific and Indian Oceans. Its current distribution stretches from the Arctic Seas to the USA in the West Atlantic and to the Gulf of Guinea in the East Atlantic and throughout the whole Mediterranean Sea to the coast of Israel. In West Africa, it was collected from Morocco [Billard 1906b; Patriti 1970, both as Thecocarpus myriophyllum (Linnaeus, 1758); Ans��n Ag��s et al. 2001], West Sahara (Vervoort 2006), Canary Islands (Bedot 1921b, as T. myriophyllum; Ans��n Ag��s et al. 2001), Mauritania (Ans��n Ag��s et al. 2001; Vervoort 2006; Gil & Ramil 2017a), Cape Verde Islands (Billard 1906b, as T. myriophyllum; Ans��n Ag��s et al. 2001), Senegal (Vervoort 1959, as T. myriophyllum), Guinea-Bissau (Gili et al. 1989, as T. myriophyllum), Sierra Leone (Vervoort 1959, as T. myriophyllum), Liberia (Broch 1914, as T. myriophyllum), Ghana (Buchanan 1957, as T. myriophyllum) and the Gulf of Guinea (Redier 1965, as Aglaophenia myriophyllum). Its bathymetric range extends from 5 to 1800 m (Ramil & Vervoort 1992; Ans��n Ag��s et al. 2001). The colony examined by us was collected at a depth of 462 m, close to the Senegalese border. Remarks. This material falls within the variations described by Ramil & Vervoort (1992) and Ans��n Ag��s et al. (2001) for Lytocarpia myriophyllum., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on page 432, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Linnaeus, C. (1758) Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. Laurentii Salvii, Holmiae, 823 pp. https: // doi. org / 10.5962 / bhl. title. 542","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Ramil, F., Vervoort, W. & Ansin, J. A. (1998) Report on the Haleciidae and Plumularioidea (Cnidaria, Hydrozoa) collected by the French SEAMOUNT 1 expedition. Zoologische Verhandelingen, Leiden, 322, 1 - 42.","Ansin Agis, J., Ramil, F. & Vervoort, W. (2001) Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, The Netherlands. Zoologische verhandelingen, Leiden, 333, 1 - 268.","Di Camillo, C. G., Boero, F., Gravili, C., Previati, M., Torsani, F. & Cerrano, C. (2013) Distribution, ecology and morphology of Lytocarpia myriophyllum (Cnidaria: Hydrozoa), a Mediterranean Sea habitat former to protect. Biodiversity and Conservation, 22,773 - 789. https: // doi. org / 10.1007 / s 10531 - 013 - 0449 - 9","Billard, A. (1906 b) Hydroides. In: Expeditions scientifiques du \" Travailleur \" et du \" Talisman \" pendant les annees 1880, 1881, 1882, 1883, etc. Masson & Cie., Paris, pp. 153 - 243.","Patriti, G. (1970) Catalogue des cnidaires et ctenaires des cotes Atlantiques marocaines. Travaux de l'Institut Scientifique Cherifien, Serie Zoologique, 35, 1 - 149.","Vervoort, W. (2006) Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania-II expeditions of the National Hystory, Leiden, the Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden, 80, 181 - 318.","Bedot, M. (1921 b) Hydroides provenant des campagnes des yachts Hirondelle et Princesse-Alice (1887 - 1912). I. Plumulariidae. Resultats des Campagnes scientifiques accomplies sur son yacht par le Prince Albert Ier de Monaco, 60, 1 - 73.","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11","Gili, J. M., Vervoort, W. & Pages, F. (1989) Hydroids from the West African coast: Guinea Bissau, Namibia and South Africa. Scientia Marina, 53 (1), 67 - 112.","Broch, H. (1914) Hydrozoa benthonica. In: Michaelsen, W. (Ed.), Beitrage zur Kenntnis der Meeresfauna Westafrikas. Vol. 1. Friederichsen, Hamburg, pp. 19 - 50.","Buchanan, J. B. (1957) The hydroid fauna of the Gold Coast. Revue de Zoologie et de Botanique Africaines, 56 (3 - 4), 349 - 372.","Redier, L. (1965) Hydraires et Bryozoaires du Golfe de Guinee. Bulletin du Museum National D'Histoire Naturelle, 37, 367 - 394."]}

Zygophylax levinseni (Saemundsson, 1911) Zygophylax levinseni: Ramil & Vervoort, 1992: 78���82, figs. 18a���d, 19a���f; Calder & Vervoort, 1998: 35���37, fig. 17a���c; Schuchert, 2001: 71���72; Vervoort, 2006: 240���242, fig. 16. Material examined. MAURIT-1011, stn MUDR20, 16��08��11���N, 16��56��08���W, 405 m, 7-XII-2010: one fragment, without coppiniae. Biology. This species was collected from bottoms of L. pertusa and M. oculata (Altuna Prados & ��lvarez Claudio 1994) and was found growing on a sponge, Acryptolaria longitheca (Allman, 1877) (Calder & Vervoort 1998) and a gorgonian axis (Vervoort 2006). Coppiniae have been found only in December (Ramil & Vervoort 1992). Distribution. Zygophylax levinseni has a Northeast Atlantic distribution, from South of Iceland to south of Cape Verde Islands, including the Mid-Atlantic Ridge (Schuchert 2001; Vervoort 2006). The records of the species were summarised by Vervoort (2006). In West Africa, it was collected from Morocco (Ramil & Vervoort 1992), Mauritania (Gil & Ramil 2017a) and Cape Verde Islands (Vervoort 2006). Its bathymetric distribution is between 183 (Altuna Prados & ��lvarez Claudio 1994) and 3647 m (Ramil & Vervoort 1992). Our material was obtained from a depth of 405 m. Remarks. Although our colony is only a fragment, it is consistent with the material described by Ramil & Vervoort (1992)., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on page 426, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Saemundsson, B. (1911) Bidrag til Kundskaben om de islandske Hydroider. II. Videnskabelige Meddelelser fra Den Danske Naturhistoriske Forening, 63, 67 - 107.","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Calder, D. R. & Vervoort, W. (1998) Some hydroids (Cnidaria: Hydrozoa) from the Mid-Atlantic Ridge, in the North Atlantic Ocean. Zoologische verhandelingen, Leiden, 319, 1 - 65.","Schuchert, P. (2001) Hydroids of Greenland and Iceland (Cnidaria, Hydrozoa). Bioscience, 53, 1 - 185.","Vervoort, W. (2006) Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania-II expeditions of the National Hystory, Leiden, the Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden, 80, 181 - 318.","Altuna Prados, A. & Alvarez Claudio, C. (1994) El genero Zygophylax Quelch, 1885 (Cnidaria, Hydrozoa) en el Golfo de Vizcaya. Miscel. lania Zoologica, 17, 1 - 16.","Allman, G. J. (1877) Report on the Hydroida collected during the exploration of the Gulf Stream by L. F. de Pourtales, assistant United States Coast Survey. Memoirs of the Museum of Comparative Zoology at Harvard College, 5 (2), 1 - 66. https: // doi. org / 10.5962 / bhl. title. 15852","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11"]}

Sertularella gayi (Lamouroux, 1821) (Fig. 3 B���D) Sertularella gayi gayi: Ramil & Vervoort, 1992: 219���222, fig. 61a���e; Medel & Vervoort, 1998: 40���45, fig. 10���11; Vervoort, 2006: 267. Sertularella gayi: Billard, 1906a: 184���185, fig. 9; Billard, 1906b:73; Billard, 1931: 675; Buchanan, 1957: 366; Vervoort, 1959: 273���275, figs. 33B���C, 34B; Redier, 1965: 373; Rees & Thursfield, 1965: 134; Vervoort, 1966: 127���128, fig. 30; Patriti, 1970: 37���38, fig. 48; Gili et al., 1989: 102���103, fig. 27; Ramil et al., 1992: 496���500, figs. 1a, 2���3. Material examined. MAURIT-0911, stn MUDR01, 16��08��24���N, 16��57��12���W, 488 m, 5-XII-2009: four colonies, without gonothecae. MAURIT-0911, stn MUDR02, 16��08��50���N, 16��57��01���W, 462 m, 5-XII-2009: two colonies, no gonothecae. MAURIT-1011, stn MUDR10, 19��50��01���N, 17��37��03���W, 520 m, 22-XI-2010: one colony 30 mm high, with gonothecae. MAURIT-1011, stn MUDR20, 16��08��11���N, 16��56��08���W, 405 m, 7-XII-2010: five colonies 18���30 mm high, three of them growing on Lophelia pertusa; one colony with gonothecae. MAURIT-1011, stn MUDR21, 16��28��13���N, 16��51��43���W, 522 m, 9-XII-2010: one fragmented colony, without gonothecae. MSM 16 /3, stn GeoB 14796���5, ROV, 20��14.823���N, 17��40.178���W, 613 m, 3-XI-2010: two colonies 30 and 33 mm high, with gonothecae. MSM 16 /3, stn GeoB 14871���2, ROV, 19��08.344������ 19��08.235���N, 16��45.849������ 16��45.664���W, 427���566 m, 9-XI- 2010: two colonies 35 and 56 mm high, one growing on Lophelia pertusa, no gonothecae. MSM 16/3, stn GeoB 14886���1, ROV, 18��39.013������ 18��38.476���N, 16��43.580������ 16��43.757���W, 484���640 m, 12- XI-2010: two colonies 8 and 17 mm high, one colony on Acesta excavata and another one on Madrepora oculata; no gonothecae. MSM 16 /3, stn GeoB 14903���1, GKG, 17��32.853���N, 16��39.700���W, 414 m, 15-XI-2010: one colony 22 mm high, growing on a sponge, without gonothecae. MSM 16 /3, stn GeoB 14908���1, ROV, 17��40.213������ 17��40.191���N, 16��40.829������ 16��40.289���W, 463���574 m, 16-XI- 2010: five colonies 11���73 mm high, on Lophelia pertusa; two colonies with gonothecae. MSM 16 /3, stn GeoB 14914���1, ROV, 17��08.203������ 17��07.898���N, 16��49.478������ 16��48.878���W, 417���514 m, 17-XI- 2010: six colonies 20���55 mm high, on Acesta excavata, four of them with gonothecae. Biology. This species has been found growing on a great variety of substrata, such as stones, sponges, the hydroid Lytocarpia myriophyllum, worm tubes, gorgonians, old antipatharian axis, coral fragments, bryozoans, shell fragments and ascidians (Ramil & Vervoort 1992; Medel & Vervoort 1998; Vervoort 2006). This species was also reported anchoring directly on soft-bottom (Gil & Ramil 2017a). Fertile material has been found in March, April and between June and December (Teissier 1965; Ramil & Vervoort 1992; Ramil et al. 1992; Medel & Vervoort 1998). Our colonies were found growing on different hydroid species, the scleractinian corals L. pertusa and M. oculata, sponges and the bivalve A. excavata. Some colonies were collected with gonothecae in November and December. Distribution. This species has a wide distribution in the Atlantic, from Spitzbergen to Gough Island, including the Mediterranean Sea [Ramil & Vervoort 1992, as Sertularella gayi gayi (Lamourux, 1821)]. In West Africa, it was collected from Morocco (Billard 1906a; Patriti 1970; Ramil & Vervoort 1992, as S. gayi gayi), Mauritania (Billard 1906a, as S. gayi gayi; Billard 1931; Medel & Vervoort 1998, as S. gayi gayi; Gil & Ramil 2017a, as S. gayi gayi), Cape Verde Islands (Rees & Thursfield 1965; Medel & Vervoort 1998, Vervoort 2006, last both as S. gayi gayi), Guinea-Bissau (Gili et al. 1989), Senegal (Vervoort 1959), Ivory Coast (Vervoort 1959; Redier 1965), Ghana (Buchanan 1957, as S. gayi gayi), Congo (Vervoort 1966, as S. gayi gayi) and Angola (Gili et al. 1989). The bathymetrical distribution ranges from 9 (Ramil et al. 1992) to 1200 m (Ramil & Vervoort 1992, as S. gayi gayi). Our material was collected from depths of 405 to 640 m. Remarks. The colonies from stations GeoB 14796���5 and GeoB 14908���1 have a lot of female gonothecae between 2000 and 3000 ��m in length (fig. 3C���D). In the gonothecae, we could observe two ���lips��� flanking the apical aperture, which is characteristic of S. gayi. We observed some variations in the ramification pattern of a colony from station GeoB 14914���1. In the basal part of the colony, three consecutive branches separated from each other by only one hydrotheca were found. In the proximal part, we found two hydrothecae between consecutive branches; however, in the distal part, the colony showed the typical ramification of S. gayi (see Ramil & Vervoort 1992, as S. gayi gayi)., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on pages 429-430, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Lamouroux, J. V. F. (1821) Exposition methodique des genres de l'ordre des polypiers, avec leur description et celle des principales especes, figurees dans 84 planches; les 63 premieres appartenant a l'histoire naturelle des zoophytes d'Ellis et Solander. Agasse, Paris, 115 pp. https: // doi. org / 10.5962 / bhl. title. 11328","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Medel, M. D. & Vervoort, W. (1998) Atlantic Thyroscyphidae and Sertulariidae (Hydrozoa, Cnidaria) collected during the CAN- CAP and Mauritania II expeditions of the National Museum of Natural History, Leiden, The Netherlands. Zoologische Verhandelingen, Leiden, 320, 1 - 83.","Vervoort, W. (2006) Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania-II expeditions of the National Hystory, Leiden, the Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden, 80, 181 - 318.","Billard, A (1906 a) Hydroides. In: Mission des pecheries de la cote occidental d'Afrique, III. Actes de la Societe Linneenne de Bordeaux, 61, 69 - 76.","Billard, A. (1906 b) Hydroides. In: Expeditions scientifiques du \" Travailleur \" et du \" Talisman \" pendant les annees 1880, 1881, 1882, 1883, etc. Masson & Cie., Paris, pp. 153 - 243.","Billard, A. (1931) Hydroides de Mauritanie. Bulletin du Museum national d'histoire naturelle, Series 2, 3 (7), 673 - 678.","Buchanan, J. B. (1957) The hydroid fauna of the Gold Coast. Revue de Zoologie et de Botanique Africaines, 56 (3 - 4), 349 - 372.","Redier, L. (1965) Hydraires et Bryozoaires du Golfe de Guinee. Bulletin du Museum National D'Histoire Naturelle, 37, 367 - 394.","Rees, W. J., Thursfield, S. (1965) The hydroid collections of James Ritchie. Proceedings of the Royal Society of Edinburgh, (B), 69 (1 - 2), (2), 34 - 220. https: // doi. org / 10.1017 / S 0080455 X 00010122","Patriti, G. (1970) Catalogue des cnidaires et ctenaires des cotes Atlantiques marocaines. Travaux de l'Institut Scientifique Cherifien, Serie Zoologique, 35, 1 - 149.","Gili, J. M., Vervoort, W. & Pages, F. (1989) Hydroids from the West African coast: Guinea Bissau, Namibia and South Africa. Scientia Marina, 53 (1), 67 - 112.","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11","Teissier, G. (1965) Inventaire de la faune marine de Roscoff. Cnidaires-Ctenaires. Travaux de la Station Biologique de Roscoff, 16, 1 - 53."]}

Earleria panicula (G.O. Sars, 1874) Campanulina panicula: Cornelius, 1995a: 190���192, fig. 43. Opercularella panicula: Christiansen, 1972: 291���292; Leloup, 1974: 4���6, fig. 3; Ramil & Iglesias, 1988: 79���81, figs. 1���2; Ramil & Vervoort, 1992: 25���27, fig. 3. Opercularella denticulata: Gili et al. 1989: 75���76, fig. 6A. Racemoramus panicula: Calder, 2012: 26, fig. 24. Earleria quadrata: Schuchert et al. 2017: 177, figs. 5���6. Material examined. MAURIT-0911, stn MUDR02, 16��08��50���N, 16��57��01���W, 462 m, 5-XII-2009: one colony, badly damaged, no gonothecae. MAURIT-0911, stn MUDR07, 18��35��40���N 16��43��12���W, 460 m, 12-XII-2009: one colony, without gonothecae. Biology. The species can colonize a great variety of substrata, such as hydroids, brachiopods, pennatulids, bivalves, dead corals, polychaete tubes and ascidians (Cornelius 1995a; Calder 2012). Fertile colonies have been found in April, June, August, November and December (Ramil & Vervoort 1992; Gili et al. 1989; Cornelius 1995a; Gil & Ramil 2017a). Gonothecae were not found in our material. Distribution. Earleria panicula, including its synonyms Campanulina denticulata Clarke, 1907 and Campanulina indivisa Fraser, 1948, was considered to be widely distributed in the Atlantic, Pacific and Indian Oceans at moderately deep to deep waters (Ramil & Vervoort 1992). Nevertheless, Calder (2012) considered the material from the Pacific and Indian Oceans to be a different species (Racemoramus denticulata), and, in consequence, the current distribution of E. panicula is restricted to the East Atlantic, from Trondheimfjord, Norway (Calder 2012) to at least Namibia [Gili et al. 1989, as Opercularella denticulata (Clarke, 1907)]. In West Africa, it was collected from Morocco [Ramil & Vervoort 1992, as Opercularella panicula (Sars, 1874)] and Mauritania (Gil & Ramil 2017a). The bathymetric distribution of the species ranges from 30 to 2100 m (Christiansen 1972; Ramil & Vervoort 1992). Our material was collected from depths of 460 to 462 m. Remarks. The material was composed of two colonies with monopodial growth and a cluster of monosiphonic, unsegmented and straight branches with badly damaged terminal hydranths. This morphology was consistent with the typical structure of E. panicula, a species previously recorded in Mauritanian soft bottoms (Gil & Ramil 2017a, as R. panicula). Moreover, the Mauritanian material is identical to those reported by Ramil & Vervoort (1992) from the Alboran Sea and Ibero-Moroccan Gulf to off Casablanca. Recently, Schuchert et al. (2017) used DNA barcoding and found that Earleria quadrata (Hosia & Pag��s, 2007) is the medusa of E. panicula. However, differences in the geographical distribution of the medusa, only known in deep waters of Korsfjord (Norway), and the polyp phase, which is widely distributed in the East Atlantic, led Schuchert et al. (2017) to consider the identity of E. panicula ambiguous, since it could represent a species complex. Nevertheless, samples of Racemoramus panicula from the Alboran Sea and Gulf of C��diz showed 16S sequences almost identical to that of E. quadrata (Schuchert et al. 2017), which seems to supports its co-specificity in at least the Northeast Atlantic. Despite Schuchert et al. (2017) hesitate to synonymise both names, currently they are considered the same species (Schuchert 2018)., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on page 422, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Sars, G. O. (1874) Bidrag til Kundskaben om Norges Hydroider. Forhandlinger i Videnskabs-Selskabet i Kristiana, 1873, 91 - 150.","Cornelius, P. F. S. (1995 a) North-West European Thecate Hydroids and their Medusae. Part 1. Part 1. Introduction, Laodiceidae to Haleciidae. Synopses of the British Fauna, New Series, 50, 1 - 347.","Christiansen, B. O. (1972). The hydroid fauna of the Oslo Fjord in Norway. Norwegian Journal of Zoology, 20, 279 - 310.","Leloup, E. (1974) Hydropolypes calyptoblastiques du Chili. Report no. 48 of the Lund University Chile Expedition 1948 - 1949. Sarsia, 55, 1 - 62. https: // doi. org / 10.1080 / 00364827.1974.10411252","Ramil, F. & Iglesias, A. (1988) Sobre la presencia de Opercularella panicula (Sars, 1873) (Cnidaria, Hydrozoa) en las costas de la Peninsula Iberica. Thalassas, 6, 79 - 82.","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Gili, J. M., Vervoort, W. & Pages, F. (1989) Hydroids from the West African coast: Guinea Bissau, Namibia and South Africa. Scientia Marina, 53 (1), 67 - 112.","Calder, D. R. (2012) On a collection of hydroids (Cnidaria, Hydrozoa, Hydroidolina) from the west coast of Sweden, with a checklist of species from the region. Zootaxa, 3171 (1), 1 - 77. https: // doi. org / 10.11646 / zootaxa. 3171.1.1","Schuchert, P., Hosia, A. & Leclere, L. (2017) Identification of the polyp stage of three leptomedusa species using DNA barcoding. Revue suisse de Zoologie, 124 (1), 167 - 182.","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11","Schuchert, P. (2018) World Hydrozoa Database. Earleria panicula (G. O. Sars, 1874). Available from: http: // www. marinespecies. org / hydrozoa / aphia. php? p = taxdetails & id = 1255613 (accessed 3 September 2020)"]}

Nemertesia belini Bedot, 1916 (Fig. 4; Table 1) Nemertesia belini Bedot, 1916: 1; 1917: 43; 1921a: 35; 1921b: 24, Pl. IV figs 22–30; 1923: 215, fig. 1A–B; Rees & White, 1966: 280; Bouillon et al., 1995: 59. Not Nemertesia belini – Ansín Agís et al., 2001: 200–204, figs. 78–79, (= Nemertesia caboverdensis n. sp.) Material examined. Nemertesia belini: Syntype material: Musée Océanographique, Monaco. Campagnes Scientifiques Prince Albert 1 er de Monaco: Expedition 1895, stn 584, 38°31´– 38°30´30”N, 26°49´15”– 26°50´15”W, 845 m, 16-VII-1895: many colonies, several with damaged gonothecae. MOM 11 0139. Expedition 1897, stn 889, 37°57´30”N, 29°15´10”W, 208 m, 10-VIII-1897: one damaged stem. MOM 11 0170. Expedition 1905, stn 2.210, 39°25´N, 31°22´30”W, 1229 m, 01-IX-1905: one colony with hydrocladia alternately directed left and right in the basal part, no gonothecae. MOM 11 0199. Expedition 1903, stn without number, 32 miles ESE of Punta Este, Pico Island (Azores), 1160 m, 26-II-1903: many colonies with gonothecae. MOM 11 0213. Biology. Bedot (1921b) indicated the presence of gonothecae in February and July. Distribution. Nemertesia belini was, to date, only known in the Azores. Its bathymetric range is between 208 and 1229 m (Bedot 1916, 1921b). Description. Hydrorhiza tubular, adhering to substrate, giving rise to a monosiphonic and unbranched stem with several internal coenosarc canals. Axis divided into internodes separated by transverse nodes distinctly visible along the entire stem. Each internode with one to five apophyses distally and a variable number of nematothecae. Apophyses usually arranged in opposite pairs or verticils, in some cases also have been observed alternately directed left and right. There are a variable number of nematothecae between two consecutive apophyses. Length of apophyses varied in same colony, short basally and becoming longer distally. Basal apophyses with a small mamelon on the upper surface and four nematothecae: two axillar and two located distally to mamelon. Distal apophyses longer with a mamelon and may have up to 10 nematothecae: two axilar, two pairs above mamelon and between one and four unpaired distal nematothecae. Internal perisarc ring of varied development just under node separating the apophyses from hydrocladia. First hydrocladial internode in basal part of stem, short and ahydrothecate and provided with one or two nematothecae. Hydrocladia composed of succession of hydrothecate and ahydrothecate internodes, separated by slightly oblique nodes, but irregularly distributed, making it difficult to define a pattern for hydrocladial segmentation. Therefore, in the same colony, we have been observed hydrocladia with only hydrothecate internodes and other hydrocladia composed of hydrothecate and ahydrothecate internodes, which does not seem to be due to damage and subsequent regeneration. The regenerated part of a broken hydrocladia always shows regular heteronomous segmentation. Hydrothecate internodes with one hydrotheca and six or seven nematothecae: two or three mesial inferior, two laterals and two supracalycine nematothecae. Nevertheless, the number of nematothecae is variable between five and ten. Hydrothecae cup-shaped, adcauline wall fully adnate, abcauline wall straight and rim smooth and tilted upwards. In hydrocladia without ahydrothecate internodes, the hydrotheca is located in the middle of the internode, while in heteronomous hydrocladia it is placed in the basal half. Ahydrothecate internodes bearing one to three nematothecae, usually with two. All nematothecae bithalamic and movable. Likewise, in some hydrocladia after rupture and subsequent regeneration, three ahydrothecate internodes have been observed before the first hydrothecate internode. All internodes, hydrothecate and ahydrothecate, with two internal perisarcal rings of varied development, one in basal part and other in distal part. Gonothecae inserted on apophyses, near mamelon. Gonothecae curved, with one side clearly convex and other straight, with latero-terminal, ovoid-shaped aperture. Sex undetermined. Remarks. Bedot (1916) indicated that N. belini mainly differs from other Nemertesia species by considerable variability in the apophysis length, pattern of segmentation of the hydrocladia and number of unpaired nematothecae per hydrocladial internode (one to five mesial inferior and one or four supracalycine), making it difficult to establish diagnostic characters for the species. However, at the same time, this variability distinguishes N. belini from the other Nemertesia species. An exhaustive study of the variability in this species was published by Bedot (1921b). This species is not represented in our collection; however, review of the type material was necessary to clearly identity some samples, and its redescription is included in this study. The differences between N. belini and N. freiwaldi n. sp. are discussed below., Published as part of Gil, Marta, Ramil, Fran & Agís, José Ansín, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on pages 436-437, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Bedot, M. (1916) Sur le genre Kirchenpaueria. Revue Suisse de Zoologie, 24 (11), 637 - 648.","Bedot, M. (1917) Le genre Nemertesia. Memoire de la Societe de Physique et d'Histoire Naturelle de Geneve, 39 (1), 15 - 52.","Bedot, M. (1921 a) Notes systematiques sur les plumularides. 2 me partie. Revue Suisse de Zoologie, 29 (1), 1 - 40. https: // doi. org / 10.5962 / bhl. part. 84689","Bedot, M. (1921 b) Hydroides provenant des campagnes des yachts Hirondelle et Princesse-Alice (1887 - 1912). I. Plumulariidae. Resultats des Campagnes scientifiques accomplies sur son yacht par le Prince Albert Ier de Monaco, 60, 1 - 73.","Rees, W. J. & White, E. (1966) New records and fauna list of hydroids from the Azores. Annals and Magazine of Natural History, Series 13, 9, 271 - 284. https: // doi. org / 10.1080 / 00222936608656051","Bouillon, J., Massin, C. & Kresevic, R. (1995) Hydroidomedusae de l'Institut royal des Sciences naturelles de Belgique. Documents de travail de l'Institut royal des Sciences naturelles de Belgique, 78, 3 - 106.","Ansin Agis, J., Ramil, F. & Vervoort, W. (2001) Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, The Netherlands. Zoologische verhandelingen, Leiden, 333, 1 - 268."]}

Nemertesia caboverdensis n. sp. (Fig. 5; Table 2) Nemertesia belini: Ansín Agís, 1998: 457–460; figs. 62–63; Ansín Agís et al., 2001: 200–204, figs. 78–79 (not Nemertesia belini Bedot, 1916). Material examined. Cape Verde Islands. CANCAP, stn 6.072, 15º54´N, 23º06´W, 110 m, 13-VI-1982: six colonies 26–171 mm high, without gonothecae; paratypes (RMNH-Coel. 28754; LZM-UV slide R. 332). CANCAP, stn 6.074, 15º55´N, 23º04´W, 91 m, 13-VI-1982: one colony 53 mm high, no gonothecae; paratype (RMNH-Coel. 28762). CANCAP, stn 6.076, 15º55´N, 23º05´W, 92 m, 13-vi-1982: one colony 69 mm high, without gonothecae; paratype (RMNH-Coel. 29101). CANCAP, stn 6.078, 15º55´N, 23º06´W, 185–190 m, 13-vi-1982: one colony 92 mm high, with gonothecae; holotype (RMNH-Coel. 28788). Etymology. The specific name, caboverdensis, refers to the locality from which this new species was obtained: Cape Verde Archipelago. Biology. Gonothecae were found in June (Ansín Agís 1998; Ansín Agís et al. 2001). Distribution. Only recorded in four localities of Cape Verde Islands, between depths of 91 and 190 m (Ansín Agís 1998; Ansín Agís et al. 2001). Description. Hydrorhiza tubular, adhering to substrate, giving rise to several monosiphonic, unbranched hydrocauli, divided into internodes by straight nodes, distinctly visible along the entire stem, especially in distal part. Each internode provided with two opposite apophyses in basal part of stem and a verticil of four apophyses in distal part, with decussate disposition; moreover, each axial internode carries several nematothecae distributed under the apophyses. Length of apophyses varies, short basally and long distally; each apophysis with two axillar nematothecae, a mamelon on its upper surface and an unpaired distal nematotheca. Long apophyses may have, after the mamelon, a pair of proximal nematothecae and up to three unpaired distal nematothecae. In basal half of stem, the apophyses are short and each hydrocladium starts with a short ahydrothecate internode, provided with a single nematotheca. In distal half, with long apophyses, first internode of hydrocladium is hydrothecate because of the fusion of the first ahydrothecate internode with the apophysis. Hydrocladia composed of succession of hydrothecate internodes with slightly oblique nodes, each with one hydrotheca on distal third, two to four mesial inferior nematothecae, a pair of lateral nematothecae and occasionally a supracalycine nematotheca. Hydrothecae cup-shaped, adcauline wall fully adnate, abcauline wall straight, with the aperture perpendicular to longitudinal axis of hydrocladia; rim smooth.Ahydrothecate internodes occur but distributed without any regularity, bearing one to three nematothecae, usually as the result of node formation in basal part of succeeding hydrothecate internode; in this case, the hydrotheca occupies a central position on the internode. All nematothecae bithalamic and movable, with long and narrow basal chamber. Gonothecae inserted on apophyses, ovoid, narrowing basally into a short pedicel. Aperture latero-terminal, broadly oval. Only one type of gonothecae observed; sex unknown. A colony from Stn 6.078 showed two secondary hydrocladia arising from the interior of a hydrotheca or a small apophysis below the hydrotheca of a primary hydrocladium (fig. 5E). Remarks. Review of the type material of N. belini and study of the samples identified as N. belini by Ansín Agís (1998) and Ansín Agís et al. (2001) led us to the conclusion that they are different species.Although this species was not collected in our surveys, for comparative purposes, we have also included a description of this material. Comparison of these colonies with the type material of N. belini showed a fair similarity in morphological traits, both with respect to trophosome and gonosome. Moreover, this material also shows wide variations related to the length of apophyses, segmentation of the stem and hydrocladia, and number of nematothecae per hydrocladial internode. This variability is consistent with that described by Bedot (1916) for N. belini. Nevertheless, we found differences that, in our opinion, justify its specific separation. In N. caboverdensis n. sp., hydrothecae are disposed in distal third of internodes and its aperture is almost perpendicular to the longitudinal axis of hydrocladia, whereas in N. belini, hydrothecae are located in basal half of internodes and its aperture is clearly tilted to abcauline side (adcauline wall longer than abcauline one) (fig. 4F, G). The number of supracalycine nematothecae is also different: one to three in N. belini, two being the more common number (Bedot 1921b) versus zero to one in the N. caboverdensis n. sp., one being the most common; moreover, in N. caboverdensis n. sp., the nematothecae are longer (see Table 2). In addition, N. caboverdensis n. sp. has ahydrothecate internodes irregularly distributed along hydrocladia, whereas in N. belini, hydrocladia are composed of a succession of hydrothecate and ahydrothecate internodes as standard morphology. Material from CANCAP stn 5010, collected in the Azores area and reported by Ansín Agís (1998) and Ansín Agís et al. (2001) within N. belini, must be reviewed before its definitive identification. Some features of this colony, such as the hydrothecal aperture tilted in abcauline direction and the length of its nematothecae clearly smaller, suggest that could be a different species. Differences with N. freiwaldi n. sp. are discussed below., Published as part of Gil, Marta, Ramil, Fran & Agís, José Ansín, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on pages 439-441, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Ansin Agis, J. (1998) Plumularioidea (Cnidaria, Hydrozoa) recolectados por las expediciones holandesas \" CANCAP \" en el Atlantico nor-oriental. Tesis Doctoral, Universidade de Vigo, Vigo, Galicia, 675 pp.","Ansin Agis, J., Ramil, F. & Vervoort, W. (2001) Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, The Netherlands. Zoologische verhandelingen, Leiden, 333, 1 - 268.","Bedot, M. (1916) Sur le genre Kirchenpaueria. Revue Suisse de Zoologie, 24 (11), 637 - 648.","Bedot, M. (1921 b) Hydroides provenant des campagnes des yachts Hirondelle et Princesse-Alice (1887 - 1912). I. Plumulariidae. Resultats des Campagnes scientifiques accomplies sur son yacht par le Prince Albert Ier de Monaco, 60, 1 - 73."]}

Garveia nutans Wright, 1859 Garveia nutans: Ramil & Vervoort, 1992: 15���16; Schuchert, 2007: 251-253, fig, 21; Schuchert, 2012: 222���223, fig. 208. Material examined. MSM 16 /3, stn GeoB 14886���1, ROV, 18��39.013������18��38.476���N, 16��43.580������ 16��43.757���W, 484���640 m, 12-XI-2010: two colonies with gonophores, one colony attached to Madrepora oculata Linnaeus, 1758 and another one to Acesta excavata. Biology. Garveia nutans is frequently found growing on stones, algae, hydroids and other hard substrata in areas with strong tidal currents (Schuchert 2007). Fertile colonies have been found between February and December (Schuchert 2012; Gil & Ramil 2017a). Our colonies were found with gonophores in November. Distribution. This species has a worldwide distribution in boreal and temperate seas (Ramil & Vervoort 1992; Bouillon et al. 2006). In West Africa, G. nutans was only collected from Mauritania (Gil & Ramil 2017a). Its bathymetric range stretches from 0 (Schuchert 2007, 2012) to 1339 m (Gil & Ramil 2017a). Our material was collected from depths of 484 to 640 m., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on pages 419-420, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Wright, T. S. (1859) Observations on British zoophytes. Edinburgh new Philosophical Journal, 10, 105 - 114.","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Schuchert, P. (2007) The European athecate hydroids and their medusa (Hydrozoa, Cnidaria): Filifera Part 2. Revue suisse de Zoologie, 114, 195 - 396. https: // doi. org / 10.5962 / bhl. part. 80395","Schuchert, P. (2012) North-West European Athecate Hydroids and their Medusae. Synopses of the British Fauna, New Series, 59, 1 - 364.","Linnaeus, C. (1758) Systema naturae per regna tria naturae, secundum classes, ordines, genera, species cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. Laurentii Salvii, Holmiae, 823 pp. https: // doi. org / 10.5962 / bhl. title. 542","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11","Bouillon, J., Gravili, C., Pages, F., Gili, J. M. & Boero, F. (2006) An introduction to Hydrozoa. Editions du Museum, Paris, 591 pp."]}

Halecium sibogae marocanum Billard, 1934 Halecium sibogae marocanum: Ramil & Vervoort, 1992: 86���90, figs. 21a���e, 22a���b; Ramil et al., 1998: 7���8, fig. 1; Medel et al., 1998: 39���41, fig.5; Pe��a Cantero & Garc��a Carrascosa, 2002: 74���75, fig. 15. Material examined. MAURIT-0911, stn MUDR01, 16��08��24���N, 16��57��12���W, 488 m, 5-XII-2009: three colonies badly damaged, without gonothecae. MAURIT-0911, stn MUDR07, 18��35��40���N, 16��43��12���W, 460 m, 12-XII-2009: one colony, no gonothecae. MAURIT-1011, stn MUDR20, 16��08��11���N, 16��56��08���W, 405 m, 7-XII-2010: one colony 15 mm high, no gonothecae. MSM 16/3, stn GeoB 14908���1, ROV, 17��40.213������ 17��40.191���N, 16��40.829������ 16��40.289���W, 463���574 m, 16- XI-2010: six colonies 6���7 mm high, three colonies growing on Lophelia pertusa, one on cirriped and two on Sertularella gayi; one colony with gonothecae. Biology. This species has been reported to grow on rocks, pebbles, shell fragments, algae, other hydroids, gorgonians and worm tubes. The gonothecae have been observed in March, June, July, August (Pe��a Cantero & Garc��a Carrascosa 2002) and December (Gil & Ramil 2017a). Our colonies were found growing on L. pertusa, S. gayi and cirripeds; the female gonothecae were recorded in November. Distribution. Halecium sibogae marocanum has an Atlantic-Mediterranean distribution from the Galicia Bank (Ramil et al. 1998) to Cape Verde Islands (Medel & Vervoort 2000) and Alboran Sea in the Mediterranean (Ramil & Vervoort 1992; Pe��a Cantero & Garc��a Carrascosa 2002). In West Africa, this species was found in Morocco (Patriti 1970; Ramil & Vervoort 1992; Vervoort 2006), Canary Islands (Medel & Vervoort 2000), Mauritania (Gil & Ramil 2017a) and Cape Verde Islands (Medel & Vervoort 2000). Bathymetric distribution from 16 (Pe��a Cantero & Garc��a Carrascosa 2002) to 756 m (Ramil et al. 1998). Our material was collected from depths of 405 to 574 m. Remarks. The presence of a perisarc fold at the base of the primary hydranthophore, the rim strongly everted and the female gonothecae are characteristics of H. sibogae marocanum and help in identifying the colonies to the species level (Ramil et al. 1998)., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on pages 427-428, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Billard, A. (1934) Note sur quelques hydroides du Maroc. Bulletin de la Societe Zoologique de France, 59, 227 - 231.","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Ramil, F., Vervoort, W. & Ansin, J. A. (1998) Report on the Haleciidae and Plumularioidea (Cnidaria, Hydrozoa) collected by the French SEAMOUNT 1 expedition. Zoologische Verhandelingen, Leiden, 322, 1 - 42.","Pena Cantero, A. L. & Garcia Carrascosa, A. M. (2002) The benthic hydroid fauna of the Chafarinas Islands (Alboran Sea, western Mediterranean). Zoologische Verhandelingen, Leiden, 337, 1 - 180.","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11","Medel, M. D. & Vervoort, W. (2000) Atlantic Haleciidae and Campanulariidae (Hydrozoa, Cnidaria) collected during the CAN- CAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, The Netherlands. Zoologische Verhandelingen, Leiden, 330, 1 - 66.","Patriti, G. (1970) Catalogue des cnidaires et ctenaires des cotes Atlantiques marocaines. Travaux de l'Institut Scientifique Cherifien, Serie Zoologique, 35, 1 - 149.","Vervoort, W. (2006) Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania-II expeditions of the National Hystory, Leiden, the Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden, 80, 181 - 318."]}

Acryptolaria conferta var. minor Ramil & Vervoort, 1992 (Fig. 2B) Acriptolaria conferta var. minor Ramil & Vervoort, 1992: 43–48, figs. 8a–c, 9a–c. Acriptolaria conferta var. minor: Vervoort, 2006: 228, fig. 11a–d. Material examined. MAURIT-0911, stn MUDR01, 16º08´24”N, 16º57´12”W, 488 m, 5-XII-2009: one colony, no coppiniae. MAURIT-1011, stn MUDR20, 16º08´11”N, 16º56´08”W, 405 m, 7-XII-2010: two colonies, one colony attached to Gorgoniidae indet, without coppiniae. Biology. Colonies of A. conferta var. minor have been reported to grow on hard substrata like rocks, shell fragments, old antipatharian stems and coral fragments or as epibionts on Polyplumaria flabellata G.O. Sars, 1874 and other hydroids, gorgonians, soft corals and worm tubes (Ramil & Vervoort 1992; Vervoort 2006). Acryptolaria conferta var. minor also colonises soft bottoms and anchors directly into the sediment with a basal tuft of hydrorhizal fibres (Ramil & Vervoort 1992). Fertile material has been found in June and August (Ramil & Vervoort 1992; Vervoort 2006). In the material studied by us, one colony was found growing on the axis of a gorgonian. Distribution. This variety is known in the Alboran Sea and Ibero-Moroccan Gulf (Ramil & Vervoort 1992), Azores, south of Madeira, Canary Islands, off Cape Blanc du Nord and Cape Yubi (Morocco) and off Cape Timiris (Mauritania) (Vervoort 2006). The bathymetric range varies between depths of 135 (Ramil & Vervoort 1992) and 1835 m (Gil & Ramil 2017a). Our material was collected from depths of 405 to 488 m. Remarks. The measurements of the hydrothecae is within the size range established by Ramil & Vervoort (1992) and Vervoort (2006) for A. conferta minor and separates this material from Acryptolaria conferta conferta (Allman, 1877). The two size groups, not bridged by intermediate forms, were also found by Gil & Ramil (2017a) in Mauritanian soft bottoms, which justifies, in our opinion, in maintaining it separate from the nominal species. Because of its sympatric distribution with A. conferta, this form only represents a variety and not a subspecies (Vervoort 2006).

Halopteris catharina (Johnston, 1833) (Fig. 3F) Halopteris catharina: Ramil & Vervoort, 1992: 145���148, fig. 37e���g; Cornelius, 1995b: 126���128, fig. 29; Schuchert, 1997: 107���110, fig. 38; Ans��n Ag��s et al., 2001: 159���163, fig. 68. Material examined. MAURIT-0911, stn MUDR 01, 16��08��24���N, 16��57��12���W, 488 m, 5-XII-2009: 25 colonies, six colonies growing on bryozoans, one on sponge, three on Aglaophenia lophocarpa, three on Plumularia filicula, one on Halecium sibogae marocanum and one on Nemertesia sp.; without gonothecae. MAURIT-0911, stn MUDR02, 16��08��50���N, 16��57��01���W, 462 m, 5-XII-2009: seven colonies, no gonothecae. MAURIT-1011, stn MUDR20, 16��08��11���N, 16��56��08���W, 405 m, 7-XII-2010: two colonies, one of them attached to Aglaophenia lophocarpa, without gonothecae. MSM 16/3, stn GeoB 14796���1, ROV, 20��14.840������ 20��14.575���N, 17��40.193������ 17��40.071���W, 487���642m, 3-XI- 2010: five colonies 7���17 mm high, one on a sponge, two on Lophelia pertusa, two on Halecium beanii; without gonothecae. MSM 16 /3, stn GeoB 14801���1, BG, 20��14.762���N, 17��40.173���W, 568 m, 3-XI-2010: two colonies 7 mm high, one on Aglaophenia lophocarpa, no gonothecae. MSM 16 /3, stn GeoB 14802���1, BG, 20��14.791���N, 17��40.188���W, 595 m, 3-XI-2010: one colony on Lophelia pertusa, no gonothecae. MSM 16/3, stn GeoB 14886���1, ROV, 18��39.013������ 18��38.476���N, 16��43.580������ 16��43.757���W, 484���640 m, 12-XI- 2010: two colonies 12 mm high, one on Acesta excavata, one on Madrepora oculata, no gonothecae. Biology. Halopteris catharina has been collected frequently from other hydroids and algae, sponges, corals, worm tubes and ascidians (Ramil & Vervoort 1992; Ans��n Ag��s et al. 2001; Gravili et al. 2013). The gonothecae have been found in February and from April to September (Ans��n Ag��s et al. 2001). In our material, some colonies were found growing on sponges, other hydroid species, the scleractinians L. pertusa and M. oculata and the bivalve A. excavata. Distribution. This species has a wide distribution on both sides of the Atlantic Ocean, from the Arctic to the southern-boreal regions, including the Mediterranean Sea (Ramil & Vervoort 1992). For a detailed distribution, see Ans��n Ag��s et al. (2001). In West Africa, H. catharina was collected from Morocco (Ramil & Vervoort 1992), Mauritania (Gil & Ramil 2017a) and Cape Verde Archipelago (Ans��n Ag��s et al. 2001; Vervoort 2006). Its bathymetric range stretches from 1 to 627 m (Ans��n Ag��s et al. 2001; Gil & Ramil 2017a). The material studied by us was collected from depths of 405 to 642 m. Remarks. The plumose aspect of the colony with opposed hydrocladia and presence of a supplementary pair of lateral nematothecae helped in accurate identification of this species., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on pages 433-435, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Johnston, G. (1833) Illustrations in British zoology. Magazine of natural history and journal of zoology, botany, mineralogy, geology and meteorology, 6, 320 - 324, 497 - 499.","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Cornelius, P. F. S. (1995 b) North-West European Thecate Hydroids and their Medusae. Part 2. Sertulariidae to Campanulariidae. Synopses of the British Fauna, New Series, 50, 1 - 386.","Schuchert, P. (1997) Review of the family Halopterididae (Hydrozoa, Cnidaria). Zoologische Verhandelingen, Leiden, 309, 1 - 161.","Ansin Agis, J., Ramil, F. & Vervoort, W. (2001) Atlantic Leptolida (Hydrozoa, Cnidaria) of the families Aglaopheniidae, Halopterididae, Kirchenpaueriidae and Plumulariidae collected during the CANCAP and Mauritania-II expeditions of the National Museum of Natural History, Leiden, The Netherlands. Zoologische verhandelingen, Leiden, 333, 1 - 268.","Pictet, C. & Bedot, M. (1900) Hydraires provenant des campagnes de l' \" Hirondelle \" (1886 - 1888). Resultats des campagnes scientifiques du prince de Monaco, 18, 1 - 59, pls. 1 - 10. https: // doi. org / 10.5962 / bhl. title. 11294","Lamouroux, J. V. F. (1821) Exposition methodique des genres de l'ordre des polypiers, avec leur description et celle des principales especes, figurees dans 84 planches; les 63 premieres appartenant a l'histoire naturelle des zoophytes d'Ellis et Solander. Agasse, Paris, 115 pp. https: // doi. org / 10.5962 / bhl. title. 11328","Gravili, C., Di Camillo, C. G., Piraino, S. & Boero, F. (2013) Hydrozoan species richness in the Mediterranean Sea: past and present. Marine Ecology, 34, 41 - 62. https: // doi. org / 10.1111 / maec. 12023","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11","Vervoort, W. (2006) Leptolida (Cnidaria: Hydrozoa) collected during the CANCAP and Mauritania-II expeditions of the National Hystory, Leiden, the Netherlands [Anthoathecata, various families of Leptothecata and addenda]. Zoologische Mededelingen, Leiden, 80, 181 - 318."]}

Cirrholovenia tetranema Kramp, 1959 Egmundella amirantensis Millard & Bouillon, 1973: 40���42, fig. 5A���D; Ramil & Vervoort, 1992: 22���24, fig. 2a���d; Pe��a Cantero & Garc��a Carrascosa, 2002: 48���49, fig. 10a���d; Migotto & Cabral, 2005: 3���13, figs 1���3. Lafoeina amirantensis: Calder, 1991: 10, fig. 3; Calder & Vervoort, 1998: 15���16, fig 5a���c. Material examined. MAURIT-0911, stn MUDR05: 18��08��43���N, 16��35��42���W, 421 m, 8-XII-2009: one colony, on bryozoan, without gonothecae. Biology. This species has been reported growing mainly on other hydroids and rocks, algae and other invertebrates (Pe��a Cantero & Garc��a Carrascosa 2002; Migotto & Cabral 2005). Fertile material has been found during the austral summer in the Seychelles (Millard & Bouillon 1973) and Brazil (Migotto & Cabral 2005). The colony studied by us was found on a bryozoan. Distribution. Cirrholovenia tetranema is a circumglobal species (Calder 1991; Pe��a Cantero & Garc��a Carrascosa 2002); its geographical distribution was sumarised by Migotto & Cabral (2005). In West Africa, it was collected from Morocco (Ramil & Vervoort 1992) and Mauritania (Gil & Ramil 2017a). The bathymetric distribution ranges from 1 to 1062 m (Calder 1991; Calder & Vervoort 1998). Our material was collected from a depth of 421 m., Published as part of Gil, Marta, Ramil, Fran & Ag��s, Jos�� Ans��n, 2020, Hydroids (Cnidaria, Hydrozoa) from Mauritanian Coral Mounds, pp. 412-466 in Zootaxa 4878 (3) on page 421, DOI: 10.11646/zootaxa.4878.3.2, http://zenodo.org/record/4425132, {"references":["Kramp, P. L. (1959). Some new and little known Indo-Pacific medusae. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i KObenhavn, 121, 223 - 259.","Millard, N. A. H. & Bouillon, J. (1973) Hydroids from the Seychelles (Coelenterata). Annals Musee Royal de L'Afrique Centrale, Sciences Zoologiques, 206 (8), 1 - 106.","Ramil, F. & Vervoort, W. (1992) Report on the Hydroida collected by the \" BALGIM \" expedition in and around the Strait of Gibraltar. Zoologische Verhandelingen, Leiden, 277, 1 - 262.","Pena Cantero, A. L. & Garcia Carrascosa, A. M. (2002) The benthic hydroid fauna of the Chafarinas Islands (Alboran Sea, western Mediterranean). Zoologische Verhandelingen, Leiden, 337, 1 - 180.","Migotto, A. E. & Cabral, A. S. (2005) Lafoeina amirantensis (Cnidaria: Hydrozoa, Campanulinoidea), the hydroid stage of the medusa Cirrholovenia tetranema (Cnidaria: Hydrozoa, Lovenelloidea). Zootaxa, 919 (1), 1 - 16. https: // doi. org / 10.11646 / zootaxa. 919.1.1","Calder, D. R. (1991) Shallow-water hydroids of Bermuda. The Thecatae, exclusive of Plumularioidea. Royal Ontario Museum, Life Sciences Contributions, 154, 1 - 140.","Calder, D. R. & Vervoort, W. (1998) Some hydroids (Cnidaria: Hydrozoa) from the Mid-Atlantic Ridge, in the North Atlantic Ocean. Zoologische verhandelingen, Leiden, 319, 1 - 65.","Gil, M. & Ramil, F. (2017 a) Hydrozoans from Mauritanian Deep-Waters. In: Ramos, A., Ramil, F. & Sanz, J. L. (Eds.), Deep sea ecosystems off Mauritania: Researching marine biodiversity and habitats in West African Deep-waters. Springer, Dordrecht, pp. 419 - 444. https: // doi. org / 10.1007 / 978 - 94 - 024 - 1023 - 5 _ 11"]}