Pseudopomatias siyomensis Godwin-Austen, 1917

Fig. 10 C

Pseudopomatias siyomensis Godwin-Austen, 1917: p. 578, Figs 5 a, 6c. Pseudopomatias siyomensis — Gude 1921, pp 160–161.

Diagnosis. A large species with strong, widely-spaced ribs and well-developed peristome consisting of two readily distinguishable circles.

Description. The only known shell is corroded, the shell colour and the sculpture of the protoconch could not be observed; shell slender turriform; whorls 9 in number and they are moderately bulging, separated by rather deep suture; teleoconch finely, regularly ribbed even behind the aperture, where the spaces between the ribs are wider than on the previous whorls; ribs seem to be stronger behind the aperture; aperture rounded with not angled columellar-parietal transition and slightly angled parietal-palatal transition; peristome very much thickened and slightly reflexed; it consists of a slimmer, protruding inner and a wider outer circle.

Measurements (in mm). H: 12.2, D: 4.9 (n=1).

Differential diagnosis. P. siyomensis is larger than P. himalayae, P. abletti n. sp. and P. harl i n. sp. Moreover, P. himalayae has a wider shell and more bulging whorls, and its aperture is oblique in lateral view; P. abletti n. sp. has "reversed oblique", rather triangular aperture; P. ha r l i n. sp. has turriform shell shape, lower ribs and a thinner apertural lip, which is not divided into two separated circles. P. rei schuetzi n. sp. is slightly more slender, has a thinner apertural rim and almost smooth neck area (last half of whorl).

Type material. Siyom, Abor Hills, leg. Captain Oakes, coll. Godwin-Austen, NHMUK 3406.03.7.1. (holotype).

Distribution. P. siyomensis is known from the type locality only. See also Fig. 2 and Table 3.