Euthymella leucocephala Kosuge, 1963

Albano, Paolo G., Bakker, Piet A. J. & Sabelli, Bruno, 2019, Annotated catalogue of the types of Triphoridae (Mollusca, Gastropoda) in the Natural History Museum of the United Kingdom, London, Zoosystematics and Evolution 95 (1), pp. 161-308 : 161

Euthymella leucocephala Kosuge, 1963

Figure 58

Euthymella leucocephala Kosuge 1963b: 260-261, pl. 18, fig. 5, text figs 5, 8.

Type locality.

Ankyaba, Setouchi-machi, Amami Islands.

Type material.

Holotype: TZM Mo. 13064 (fide Kosuge 1963b; not seen, illustrated in Higo et al. 2001: 51, G1686). Paratype: NHMUK 1966139: 1 specimen, Amami Islands, Japan .

Original description.

Shell medium in size, apex blunt, conical, somewhat inflated at the middle of the spire and slightly narrowed at the body whorl. Protoconch of a single whorl, mammillate and smooth. Mature whorl 9, each whorl convex and widely separated by a rather deep grooved suture, encircled by a fine supra-sutural thread. Sculpture consists of 3 rows of granules, median row somewhat larger than the others at the lower spire, equal in size at the early 2 or 3 whorls and rapidly diminished at its first whorl; each granule spirally elongate and well elevated from the crossing points of broad axial columns and spiral costae which are deeply latticed, aparts from each other by about its diameter and 14 to a whorl. On the body whorl, fourth row of granules encircles the periphery, the other 2 slender, smooth, spiral ridges the base and the anterior canal which is short and recurved backward. Protoconch and early 2 whorls white, remainder dark reddish brown.

Shell length: 6.8 mm.

Remarks: This species is easily distinguished by its protoconch, white apex and spirally elongated granules. It is somewhat related to E. regalis Jousseaume and E. isaotakii Kosuge, though differs in its protoconch, shell shape and colour-pattern, and also differs from Notosinister atratus Kosuge in its sculpture and protoconch.

Figures

Figure 58. Triphora leucocephala Kosuge, 1963, Amami Islands, Japan. A-E, G-I Paratype, NHMUK 1966139: front (A, B), side (C, D), back (E), protoconch (G, H), aperture (I). F Original figure. J NHMUK label. Scale bars: A-E: 1 mm; G, H: 0.2 mm; I: 0.5 mm.