Seguenzia cf. S. emmeles Marshall, 1991, 1876

Herbert, David G., 2024, The Vetigastropoda (Mollusca) of Walters Shoal, with descriptions of two new genera and thirty new species, European Journal of Taxonomy 923, pp. 1-119 : 46

Seguenzia cf. S. emmeles Marshall, 1991

Fig. 19E–J

Seguenzia emmeles Marshall, 1991: 93 , figs 213–217.

Type loc.: off southern New Caledonia , 2100– 2650 m .

Material examined

WALTERS SHOAL • 1 empty shell; south plain, stn CP4913; 33°52′ S, 44°05′ E; depth 1539–1615 m; 11 May 2017; MNHN .

Remarks

A single juvenile shell in poor condition exhibits considerable similarity to Seguenzia emmeles from New Caledonia. It differs from that species in having more numerous, but weaker spiral cords on the base and a narrower umbilicus with a less strongly angled margin. In addition, whereas the inner lip of S emmeles is toothless, the specimen from Walters Shoal, even though juvenile, has a distinct rounded columella bulge. Seguenzia mirabilis Okutani, 1964 from Japan is also similar to the present specimen, but it has a closed or at most chink-like umbilicus and a strong basal columella tooth ( Okutani 2000; Sasaki 2008). Although it is possible that the differences between the specimen from Walters Shoal and S. mirablis reflect the former’s juvenile condition, it also possesses finer and more numerous axial riblets. Unusually, on the fourth whorl these are more close-set below the shoulder keel than above it (9 vs 12 per 0.5 mm). The condition of the specimen is inadequate to meaningfully evaluate its identity and thus I merely note the occurrence of a species resembling S. emmeles on the plain surrounding Walters Shoal.

Figures

Fig. 19. A–B. Fluxinella dufresneae sp. nov., juvenile paratype (MNHN-IM-2000-38058). A. Spire whorls. B. Protoconch. C–D. Hadroconus scobina sp. nov., paratype (MNHN-IM-2000-38065). C. Oblique view of spire whorls. D. Protoconch. E–J. Seguenzia cf. S. emmeles Marshall, 1991, Walters Shoal, stn CP4913, height 1.63 mm, diameter 1.50 mm (MNHN). E–G. Apertural, oblique basal and apical views of shell. H. Detail of sculpture showing more numerous axial riblets below shoulder keel. I. Side view of apex. J. Protoconch. Scale bars: A, C = 0.5 mm; B, D, J = 100 μm; E–G = 1.0 mm; H–I = 200 μm.