Vitreotubus digeronimoi Zibrowius, 1979: 184 Vitreotubus digeronimoi Serpulidae (Annelida) of the Australian Indian Ocean Territories Kupriyanova, Elena K. Flaxman, Beth Records of the Australian Museum 2024 Rec. Aust. Mus. 2024-08-28 76 4 211 242 5BMF7 Zibrowius, 1979 Zibrowius 1979 [896,1410,493,520] Polychaeta Serpulidae Vitreotubus Animalia Sabellida 26 237 Annelida species digeronimoi   Figs. 14A–C, 15A–E      Vitreotubus digeronimoi Zibrowius, 1979: 184, figs 1–2.   Vitreotubus digeronimoi–ten Hove 1994:113 ( Seychelles,  empty tubes only); Vinn, 2005: 262–262, fig. 5 (tube ultrastructure); ten Hove & Kupriyanova, 2009: 103–104, fig. 50 (SEM of chaetae).   Material examined:W.54402,  Cocos (Keeling) Islands Territory, Muirfield Seamount( 13°10'28"S, 96°14'14"E), depth  528 m,  21/10/2022(1 tube); W.54409 (LK295),  Cocos (Keeling) Islands Territory, Muirfield Seamount( 13°10'28"S, 96°14'14"E), depth  528 m,  21/10/2022( 1 spec); W.55301 (LK317), same locality ( 1 spec.prepared for SEM).  Species diagnosis.Tube entirely vitreous ( Fig. 14A, C), more or less quadrangular in cross-section, by its two large undulating ( Fig. 14C) or distinctly denticulate lateral keels ( Fig. 14C), and with a median keel made of a row of short teeth. Operculum inverse conical with chitinous diabolo-like endplate ( Fig. 14B, 15A). Seven thoracic chaetigerous segments. Collar trilobed. ( Fig. 14B, 15A).  Apomatuschaetae absent ( Fig. 15B). Thoracic uncini saw-shaped with 6–7 teeth above pointed fang ( Fig. 15C). Abdominal chaetae true trumpet-shaped, with two rows of pointed teeth bordering hollow groove and extended into a long lateral spine ( Fig. 15D). Abdominal uncini saw-shaped with about 6 teeth anteriorly ( Fig. 15E).   Remarks.The species has a very characteristically shaped transparent tube. Not surprisingly, the irregular spherulitic prismatic tube ultrastructure of  Vitreotubusclosely resembles that of  Placostegus tridentatus, a species with similarly transparent tube ( Vinn, 2005).   Zibrowius (1979)designated the station 229/  9.11.1971of RV“ Jean Charcot” Campagne Biaçorescollected NW of Santa Maria, Azores( 37°01.5'N, 25°14'W,  600 m) as the typelocality of  V. digeronimoi, but his additional materialcame from Northern(off Kuria Muria Islandsoff Omancoast) and Southern( Mayotte) Indian Oceanlocalities. Thedepth range reported for the species is  500–1415 m. Herewe provide a new record from Southern Indian Ocean( Muirfield Seamount) of this poorly known, but apparently widely distributed bathyal species and, more importantly, we provide the first DNA sequence data for this species.   Distribution. Central Atlantic and Indian Ocean; bathyal ( 500–1415 m). 2022-10-21 Cocos (Keeling) Islands 528 -13.174445 Territory 21 96.23722 Muirfield Seamount 27 238 1 2022-10-21 SEM Cocos (Keeling) Islands 528 -13.174445 Territory 21 96.23722 Muirfield Seamount 27 238 2 1971-09-11 RV Oman Muirfield Seamount 600 37.025 Campagne Biacores 744 -25.233334 Southern Indian Ocean 27 238 2