Herpetopoma, : Pilsbry, 1890

Herbert, D. G., 2012, A revision of the Chilodontidae (Gastropoda: Vetigastropoda: Seguenzioidea) of southern Africa and the south-western Indian Ocean, African Invertebrates 53 (2), pp. 381-381 : 436-437

Herpetopoma (s.s.) seychellarum (G. & H. Nevill, 1869) comb. n.

Fig. 29 Euchelus seychellarum : G. & H. Nevill 1869: 157, pl. xvii, fig. 107; Pilsbry 1890 in 1889–90: 438, pl. 57,

fig. 13. Type loc.: Island of Mahé, Seychelles. Type material: Five syntypes of Euchelus seychellarum G. & H. Nevill, 1869, in the Indian Museum , Kolkata (M13143/2), one is here figured and designated lectotype .

Remarks: This species does not appear to have been recorded subsequent to the original description. Its small size (diameter 2.8 mm), depressed profile and wide umbilicus, together with the distinct, peg-like basal columella tooth and dentate interior of the outer lip render it easily separable from other south-western Indian Ocean chilodontids. Obviously such small species are easily overlooked, but the evident absence of additional material from the Seychelles raises the possibility that the original material was mislocalised. Comparison with taxa from other areas may shed further light on this subject. The Philippine H. exasperatum (A. Adams, 1853) has a similarly depressed shape, but is larger (diameter attaining 6.5 mm) and has spiral cords of alternating size and crisper sculpture ( Fig. 68E, F ).

Figures

Fig. 29. Herpetopoma seychellarum (G. & H. Nevill, 1869): lectotype (here designated) of Euchelus seychellarum G. &H.Nevill, 1869,diameter 2.8 mm (Indian Museum,Kolkata,M13143/2; photographs courtesy of R. Kilburn).

Fig.68.Ascetostomaand Herpetopoma species examined forcomparison:(A,B) Euchelus ringens Schepman, 1908, holotype, Sulu Archipelago, Indonesia, length 7.8 mm, diameter 7.5 mm [not length 7.5 mm, diameter 8.0 mm as given bySchepman] (ZMAN 3.08.092); (C, D)Clanculus crassilabrum Sowerby, 1905,one of three syntypes,specimen marked with an X, Sri Lanka, length 7.0 mm, diameter 6.4 mm (NHMUK 1905.10.23.41–43); (E, F) Monodonta exasperata A.Adams, 1853, one of four syntypes, Sibonga Is. [Cebu], Philippines, length 6.0 mm, diameter 6.5 mm (NMHUK 196875).