Imeretiopsis nakeralaensis Grego & Mumladze, 2020

Grego, Jozef, Mumladze, Levan, Falniowski, Andrzej, Osikowski, Artur, Rysiewska, Aleksandra, Palatov, Dimitry M. & Hofman, Sebastian, 2020, Revealing the stygobiotic and crenobiotic molluscan biodiversity hotspot in Caucasus: Part I. The phylogeny of stygobiotic Sadlerianinae Szarowska, 2006 (Mollusca, Gastropoda, Hydrobiidae) from Georgia with descriptions of five new genera and twenty-one new species, ZooKeys 955, pp. 1-77 : 1

Imeretiopsis nakeralaensis Grego & Mumladze sp. nov. Plate 9 (9)

Type locality.

Georgia • Imereti, Tkibuli, Tkibuli-Nikortsminda road to Nakerala Pass (ნაქერალას უღელტეხილი); 42°23'00"N, 42°00'45"E; 980 m a.s.l.; spring above left side of road with small travertine waterfall and a small spring cavern entrance.

Material.

Holotype: Georgia • 1 adult, dry; type locality; 04 May 2018; J. Grego, L. Mumladze and M. Olšavský leg.; ISU FM-T015-H. Paratypes: Georgia • same as for holotype; ISU FM-T015-P1/10 dry, SBMNH 633110/2 dry, NHMW 113371/1 dry, NHMB 563969/2 dry, coll. JG F1009/10 dry, coll. Glöer /1 dry.

Diagnosis.

The new species differs from all the morphotypes with related shell shape in the region by its more robust oval shape, by the position of the aperture more right of the columella (to viewer; shell in apertural pose, apex up), and by the more open umbilicus. Caucasogeyeria shakuranica (Starobogatov, 1962) from Abkhazia has similar but narrower shell shape with less inflated whorls and a proportionally smaller body whorl. Caucasogeyeria letsurtsume sp. nov. has a smaller shell with more inflated whorls and more open umbilicus.

Description.

Shell: 2 mm high, elongate ovate-conical with pronounced protoconch, five tumid whorls and moderately deep suture. Shell surface whitish, translucent-glossy, covered by faint axial growth lines. Umbilicus open. Proportionally small aperture irregular, almost round, not expanded, with straight lateral and columellar labral profiles lacking sinuation. Protoconch surface densely and coarsely pitted.

Operculum: not known.

Animal body: not known.

Holotype measurements: H-2.00 mm; W-1.09 mm; BH-1.02 mm; BW-0.85 mm; AH-0.64 mm; AW-0.53 mm; CA: 29°.

Anatomy: not known.

Etymology.

Name after the Nakerala Pass 1218 m alt. situated above the type locality north of Tikbuli along the road to Ambrolauri.

Habitat.

Stygobiotic species. The empty shells of the species were found at the foot of small travertine cascade formed by a small stream emerging from the very narrow cave spring (small entrance covered by moss and ivy). Only a few shells were found in sparse sediments accumulated near the cave walls. The shells were washed out from its subterranean habitat by the very small permanent stream.

Distribution.

Only known from the type locality.

Conservation status.

The number of known locations (1) is no more than 5 and EOO is smaller than 20 km2. There is no reason to suppose that AOO, EOO, number of locations, number of subpopulations or the number or mature individuals are declining however due to its extremely small EOO we assessed as Vulnerable (VU) D2.

Remarks.

The assignment of the new species to the genus Imeretiopsis gen. nov. is only provisional, based on the resemblance if its shell to that of the type species. However, molecular data will be essential to confirm generic placement.

Figures

Plate 9. 1 Caucasopsis olsavskyi sp. nov., Samegrelo, Chkhorotsku, Nazodelavo Cave, holotype 2 C. letsurtsume sp. nov., Samegrelo, Chkhorotsku, Letsurtsume, Letsurtsume Cave, holotype 3 C. letsurtsume sp. nov., Samegrelo, Chkhorotsku, Kachara Cave 4 C. egrisi sp. nov., Samegrelo, Pirveli Balda, Motena Cave form 5, 6 C. egrisi sp. nov., Samegrelo, Pirveli Balda, spring in village: 5 holotype 6 paratype 7 Imeretiopsis prometheus sp. nov., Imereti, Kumistavi, Prometheus Cave, holotype 8 I. cameroni sp. nov., Imereti, Kutaisi, Iazoni (Tskhal-Tsiteli) Cave Spring, holotype 9 I. nakeralaensis sp. nov., Imereti, Tikibuli, spring above Tikibuli-Nikortsminda road to Nakerala pass, holotype 10 C. letsurtsume sp. nov., Samegrelo, Chkhorotsku, Letsurtsume, Letsurtsume Cave, robust morphotype. The numbers correspond to individuals, and the letters represent the different views of the same individual. Photograph J. Grego.