Alomasoma belyaevi Zenkevitch 1964

• Main Author: Biseswar, Ramlall
• Format: Text
• Language: unknown
• Published: Zenodo 2010
• Subjects: Biodiversity; Taxonomy; Animalia; Echiura; Polychaeta; Echiuroidea; Bonelliidae; Alomasoma; Alomasoma belyaevi; Antarctic; Pacific; Antarc*
• Online Access: https://dx.doi.org/10.5281/zenodo.4559915; https://zenodo.org/record/4559915

Alomasoma belyaevi Zenkevitch, 1964 (Fig. 1A, B) MATERIAL EXAMINED. — East Equatorial Atlantic Ocean. Gulf of Guinea, BIOZAIRE 3, CP 10, stn ZB-D, 5°50.6300’S, 8°20.0600’E, 3977 m, 19.XII.2003, 1 ♀. — CP 11, stn ZB-D, 05°50.5840’S, 008°20.0380’E, 3978 m, 20.XII.2003, 1 ♀. — CP 22, stn R 10, 05°46.9700’S, 009°44.1828’E, 3121 m, 3.I.2004, 1 ♀. DESCRIPTION Colour of trunk of preserved specimens is reddishbrown. In one female only small proximal part of proboscis is attached to trunk, rest damaged.Trunk is cylindrical, 30 mm long and 12 mm across broadest part. Part of body wall damaged on ventral side of trunk. In other two specimens, probosces are missing and posterior ends of trunk are damaged. Anterior end of trunk covered with small rounded papillae, remainder of trunk smooth and devoid of papillae. Single genital pore is located about 5 mm away from anterior end of trunk (Fig. 1A). Ventral setae absent. Gonoducts one pair (Fig. 1B), large, sac-like, uniting proximally beneath nerve cord and opening to exterior by single genital pore. In one female, gonoducts compactly filled with eggs. Gonostomes small, basal in position (Fig. 1B). Gonostomal lips with minute lobes around margin. Except for oesophagus and foregut, rest of alimentary canal is damaged in all specimens including blood system and anal vesicles. REMARKS Alomasoma belyaevi was originally described by Zenkevitch (1964) from the North-West Pacific Ocean at depths ranging from 2826-2843 m. Zenkevitch (1966) also reported the occurrence of this species in the Gulf of Panama. Alomasoma belyaevi has been recorded and briefly described by Saiz-Salinas et al . (2000) from Antarctic and adjacent waters. The latter authors have described male specimens in the genus Alomasoma for the first time. According to Stephen & Edmonds (1972) all the specimens have been found at great depths. The anatomy of this species is fairly well known as it has been described from numerous specimens. Alomasoma belyaevi is close to A. rhynchollulus DattaGupta, 1981 from the North Atlantic.According to DattaGupta (1981), A. rhynchollulus differs from all the other species in the genus in possessing a minute triangular proboscis. The discovery of A. belyaevi from the East Equatorial Atlantic Ocean is a new record for this region which considerably extends its range of distribution. : Published as part of Biseswar, Ramlall, 2010, Report on deep-sea bonelliids (Echiura) from the East Equatorial Atlantic Ocean, pp. 139-154 in Zoosystema 32 (1) on page 141, DOI: 10.5252/z2010n1a7, http://zenodo.org/record/4520699 : {"references": ["ZENKEVITCH L. A. 1964. - [New representatives of deep-sea echiurids Alomasoma belyaevi Zenk. sp. n. and Choanostoma filatovae n. sp. in the Pacific]. Zoologicheskii Zhurnal 43: 1863 - 1884 (in Russian).", "ZENKEVITCH L. A. 1966. - The systematics and distribution of abyssal and hadal (ultraabyssal) Echiuroidea. Galathea Report 8: 175 - 184.", "STEPHEN A. C. & EDMONDS S. J. 1972. - The Phyla Sipuncula and Echiura. The British Museum (Natural History), London, 508 p.", "DATTAGUPTA A. K. 1981. - Atlantic echiurans. Part 1. Report on twenty-two species of deep-sea echiurans of the North and the South Atlantic Oceans. Bulletin du Museum national d'Histoire naturelle Paris, 4 e serie, sect. A, 3 (2): 353 - 378."]}