Schapsugia Chertoprud, Palatov & Vinarski, 2021

Chertoprud, Elizaveta M., Palatov, Dmitri M. & Vinarski, Maxim V., 2021, Revealing the stygobiont and crenobiont Mollusca biodiversity hotspot in the Caucasus: Part III. Revision of stygobiont microsnails (Mollusca: Gastropoda: Hydrobiidae) from the Russian part of Western Transcaucasia, with the description of new taxa, Zootaxa 5005 (3), pp. 257-275 : 266

Genus Schapsugia Chertoprud, Palatov & Vinarski , gen. nov.

Type species. Paladilhiopsis pulcherrima Starobogatov, 1962

Gender. Feminine.

Diagnosis. Shell small, turriculate to conical-ovoid, relatively slender, with strongly inflated and slowly increasing whorls separated by deep suture. Spire high, body whorl oblong and slightly convex, its’ height exceeds 0.50 SH. Aperture triangular-ovoid, with a more or less obtuse angle in its upper part, leaned against body whorl wall forming a slit-like umbilicus. Protoconch broad, low domed-shaped. Surface of embryonic shell is covered in its initial part by irregularly arranged pits which turn into thin spiral and short wrinkles towards the end of the first whorl. Operculum ovoid. Radula : taenioglossate. The rachis bears 4–5 cusps on each side of the median cusp and one pair of basal cusps, basal tongue narrow, V-shaped; lateral tooth with 9 or 11 cusps (4 or 5 at the inner side, one largest, 4 or 5 at the outer side); inner marginal tooth with 20 cusps, outer marginal tooth with 17–18 cusps ( Fig. 6E , 7F ). Penis large, flattened, with medial lobe on inner edge. Lobe shape varies from small warty-shaped bulge to well visible paddle-shaped outgrowth. Distal part of the penis has a delicate fin-shaped edging, which is easily damaged during dissection and is rarely preserved on the specimen in its original form ( Fig. 6H , 7G, 7P ). Animal blind, with depigmented body.

From all genera of Caucasian hydrobiid snails, established to date, Schapsugia gen. nov. differs by a unique combination of general shell shape and penis structure.

Etymology. Named after the ancient Adyghe tribe called Shapsug, originally inhabiting extensive territories of the Black Sea coast and the Kuban River basin; the type locality of the type species of the genus lies within the territory that belonged, in former times, to this tribe.

Species composition. Three species, all endemic to the Krasnodar Krai of Russia.

Figures

FIGURE 6. Schapsugia pulcherrima (A–J) and Tachira valvataeformis (K–R). A, B, K, L—shell; C, M—operculum: inner and outer sides; E, O—radulae; F–H, P—penis structure; D, N—protoconch, lateral view; J, Q—protoconch surface sculpture; I, R—protoconch, apical view. F, G correspond to individuals identified as ‘Paladilhiopsis orientalis’, H—‘P. pulcherrima’. White arrow points to the fin-like edging of the penis. Scale bars: A, B, J, K—500 μm; R—200 μm; F, G, H, K, L—250 μm; C, D, I, M, N—100 μm; E, J, Q—20 μm; O—10 μm.

FIGURE 7. Schapsugia kudepsta sp. nov. (A–I) and Schapsugia occultata sp. nov. (J–R). A, J—shell, holotype; B, C, K, L—shell; D, M—protoconch, lateral view; E, N, O—protoconch surface sculpture; F—radula; G, P—penis structure; H, I, Q, R—protoconch, apical view. White arrow points to the fin-like edging of the penis. Scale bars: A–C, J–L—500 μm; G, P—250 μm; D, H, I, M, Q, R—100 μm; E, N, O—20 μm; F—10 μm.