Caucasogeyeria ignidona Grego & Palatov, 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

Caucasogeyeria ignidona Grego & Palatov sp. nov. Plate 15 (1); Fig. 14A-C

Type locality.

Georgia • Imereti, Kumistavi, Prometheus Cave (პრომეთეს მღვიმე); 42°22'33"N, 42°36'2"E; 175 m a.s.l.; bottom of cave stream.

Material.

Holotype: Georgia • adult, dry; type locality; 01 May 2018; J. Grego, L. Mumladze and M. Olšavský leg.; ISU FM-T005-H. Paratypes: Georgia • same as for holotype; ISU FM-T005-P1/1 dry and 1 wet, coll. JG F0969/1 dry and 2 wet.

Diagnosis.

The new species can be distinguished from other members of the genus by the typical shell aperture. Caucasogeyeria gloeri sp. nov. has a larger, more robust shell with different aperture, C. colchis sp. nov. has more sinuated and more deeply cut labral margin at its columellar side, and C. chrysomallos sp. nov. has smaller, more conical and elongate shell with a greater number of whorls and proportionally smaller, differently shaped aperture.

Description.

Shell: conical with blunt protoconch and with 3½ inflated whorls separated by semi-deep suture. Height 1.4-1.7 mm. Shell surface milky white, glossy with occasional rusty brown incrustations. Aperture expanded, proportionally larger, rhomboidal with a weak negative sinuation at labral junction with the body whorl and a weak positive sinuation at columellar margin. Umbilicus slit-like.

Operculum: paucispiral, glass-like translucent.

Animal body: white, without eye spots.

Holotype measurements: H-1.60 mm; W-1.10 mm; BH-1.15 mm; BW-0.9 mm; AH-0.85 mm; AW-0.70 mm; CA: 28°.

Anatomy: the penis (Fig. 14A-C ) bent, simple, narrow, gradually narrowing towards its distal end, vas deferens inside running straight.

Etymology.

Name derived from Latin word ignidona meaning of "donating fire", referring to the gift of Prometheus to the mankind, indirectly indicating the name of type locality in the Prometheus Cave near Kutaisi.

Habitat.

Stygobiotic species. Live individuals of the new species were found in the cave stream on submerged stones and gravel, covered by a layer of dark brown-black layer of bacterial mats. Empty shells were found in sandy sediment of the cave 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 sympatric Imeretiopsis prometheus sp. nov. has more numerous populations throughout the cave stream. It is not clear whether both species share the micro-habitats within the same cave stream.

Figures

Figure 14. A-C Caucasogeyeria ignidona sp. nov., Imereti, Kumistavi, Prometheus Cave D C. chrysomallos sp. nov., Kanti, Mapeli Spring, morphology of the penis. Photograph A. Falniowski and A. Rysiewska.

Plate 15. 1 Caucasogeyeria ignidona sp. nov., Imereti, Kumistavi, Prometheus Cave, holotype 2 Caucasogeyeria colchis sp. nov., Samegrelo, Pirveli Balda, Motena Cave, holotype 3 Caucasogeyeria colchis sp. nov., Samegrelo, Pirveli Balda, spring in village, holotype 4 Caucasogeyeria colchis sp. nov., Imereti, Nakhriduri 2 left side spring in Turchu Gamosadivari Basin above small ford, paratype 5 - 8 Caucasogeyeria pseudocolchis sp. nov., Samegrelo, Mukhuri, Shisha Spring 5 holotype 6 - 8 paratypes. The numbers correspond to individuals, and the letters represent the different views of the same individual. Photograph J. Grego.