Type locality. Between Marion Island and Prince Edward Island, Challenger, stn 145, 46°43'S, 38° 04'30'E, 256 m; Royal Sound, Kerguelen Islands, Challenger, stn 149b, 49°28'S, 70°30'E, 46 m; and 149d, Royal Sound, Kerguelen Islands, 49°28'S, 70°13'E, 51 m.
Morphology
Protoconch paucispiral, c.2.5 whorls, obtuse, conical, nearly smooth. Diameter (syntype) 1.12 mm, height 0.9 mm (Numanami 1996: fig. 157, diameter 1.2, height 0.8 mm).
Radula (Numanami 1996:figs 157D, 157E),of very short hypodermic, loosely enrolled marginal teeth. Length c.55 um (0.75% of AL), conic, unbarbed, with very wide basal opening of tooth canal spanning about one-half of tooth length, and long slit-like apical opening, spanning about one-fifth of tooth length. Small outgrowth at the level of upper part of basal opening probably homologous to spur. Teeth with well-developed ligament.
Remarks
Pleurotoma (Thesbia) translucida was attributed to the genus Typhlodaphne Powell, 1951 (type species Bela purissima Strebel, 1908) by Powell (1951: 175). However, the type species of Typhlodaphne has an operculum and, based on the morphology of its foregut and radula, belongs to the family Borsoniidae. Numamani (1996: 224) provisionally transferred this species to Xanthodaphne on the basis of its shell and radular morphology and lack of operculum.
The radula of this species, which consists of short, simplified, marginal hypodermic teeth, clearly indicates its position within Raphitomidae, while the shell of X. translucida closely resembles that of X. membranacea (Watson, 1886), the type species of Xanthodaphne.
Distribution
Marion Island, 99-113 m, Kerguelen Islands, 20-168 m, off the Crozet Islands ( 115-205 m), Enderby Land, Antarctic continent between 49°E-53°E, 193-300 m (Powell 1960; Dell 1990), live 275-289 m (Numanami 1996).