Type-species: Bathyvermilia challengeri Zibrowius, 1973
Generic diagnosis (after ten Hove & Kupriyanova 2009). Tube white, opaque, circular in cross-section, longitudinal keel(s) present or absent. Collar-like rings present. Granular overlay absent. Operculum sub-globular, with simple flat to slightly conical chitinous endplate, sometimes encrusted by calcareous deposit. Peduncle cylindrical, FIGURE 3. SEM micrographs of chaetae in Bathyditrupa hovei, R/V “ Vityaz ” Stn. 4370. A—collar chaetae, B—bundle of thoracic chaetae, C—anterior abdominal chaeta, D—uncini from 5 th thoracic chaetiger, E—uncini from 1 st abdominal chaetiger. Scale: A— 2 μm, B— 5 μm, C— 1 μm, D, E— 2 μm.
smooth or wrinkled, distal wings absent; inserted as 2 nd dorsal radiole on either side, constriction present. Pseudoperculum absent. Up to 35 radioles per lobe arranged in semi-circles. Inter-radiolar membrane, branchial eyes, and stylodes all absent. Mouth palps present or absent. Seven thoracic chaetigerous segments, four of which uncinigerous. Trilobed collar (may be not divided into lobes in some taxa) with straight edge, tonguelets absent. Thoracic membranes of variable length, extending to 2 nd– 7 th thoracic segment. Collar chaetae limbate capillaries. Apomatus chaetae present. Thoracic uncini saw-shaped, with 6-10 teeth and simple, pointed anterior fang. Abdominal chaetae flat, narrow geniculate with blunt teeth. Anterior and mid-abdominal uncini saw-shaped, uncini on few far posterior segments rasp-shaped. Short achaetous anterior abdominal zone present. Posterior capillary chaetae present. Posterior glandular pad present.
Remarks. Ten Hove & Kupriyanova (2009) list five bathyal and abyssal species in this genus, including three (B. challengeri Zibrowius, 1973, B. kupriyanovae Bastida-Zavala, 2008, and B. zibrowiusi Kupriyanova, 1993 b) from the Pacific Ocean. Recently, Kupriyanova & Nishi (2010) added another species from the Patton-Murray Seamount, Gulf of Alaska by transferring Vermiliopsis (?) eliasoni Zibrowius, 1970 to Bathyvermilia.
Bathyvermilia is morphologically similar to Metavermilia Bush, 1905 sensu Zibrowius, 1971, Pseudovermilia Bush, 1907, Semivermilia ten Hove, 1975, and Vermiliopsis Saint-Joseph, 1894, all of them previously united under Vermiliopsis. The distinction among these genera is based upon the characters, such as the morphology of the uncinal anterior peg, the position of insertion and the shape of the peduncle, and the tube structure (Zibrowius 1973, ten Hove 1975), which are either rather subtle or quite variable among the species of the group (the flat ribbon-like peduncle of Metavermilia being the only exception). The relationships among the groups or whether any of the nominal genera constitute monophyletic groups remain uknown.