Imeretiopsis prometheus 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

Imeretiopsis prometheus Grego & Palatov sp. nov. Plates 6 (1-6); 7(1); 9(7)

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 • 1 adult, dry; type locality; 01 May 2018; J. Grego, L. Mumladze and M. Olšavský leg.; ISU FM-T017-H. Paratypes: Georgia • same as for holotype; ISU FM-T017-P1/21 dry, SBMNH 633098/4 dry, NHMW 113372/1 dry, HNHM 104682/1 dry, NHMUK 20191338/1 dry, NHMB 563970/1 dry, SMF 358929/1 dry, ZMH140634/1 dry, NHMW 113372/1 dry, ZIN 1/508-2020/1 dry, coll. JG F/21 dry and 2 wet, coll. Glöer /1 dry.

Diagnosis.

The species differs from all the related morphotypes from the Caucasus by the more conical-elongate shell with typical triangular shell shape, by the more oval aperture situated more right of the columellar axis (to viewer; shell in apertural pose, apex up). I. cameroni sp. nov. has a much narrower elongated shell shape with a more elongated aperture and less inflated whorls with closed umbilicus, and I. nakeralaensis sp. nov. has more robust, oval shell with proportionally smaller aperture and narrower umbilicus.

Description.

Shell: elongate-conical, 1.42-1.66 mm high with five whorls, blunt protoconch, inflated whorls, deep suture and proportionally larger body whorl. Umbilicus narrow, slit like. Shell surface glossy, translucent with horny-yellowish periostracum, occasionally covered by rusty-brown inorganic incrustations. Aperture irregularly ovate, slightly expanded, separated from body whorl by a grove and by broadening adapical apertural gap. Lateral labral profile weakly sinuated, columellar profile straight. Protoconch strongly pitted.

Operculum: yellowish, translucent, elongate ellipsoid, paucispiral with excentric nucleus.

Animal body: eyeless, milky whitish coloured with light brown pellets.

Holotype measurements: H-1.66 mm; W-0.53 mm; BH-0.87 mm; BW-0.72 mm; AH-0.60 mm; AW-0.47 mm; CA: 33°.

Etymology.

Name is derived from the type locality inside Prometheus Cave (პრომეთეს მღვიმე). The cave was named after Prometheus, the Titan of Greek mythology, who created mankind from clay, stealing the fire from gods and providing it to humanity. As punishment, he was eternally bound to a rock at Caucasus Mountains, where each day an eagle was sent to feed on his liver.

Habitat.

Stygobiotic species. Empty shells of the new species were found among the sandy sediments inside the cave stream of Prometheus Cave. Live individuals were found attached at the slimy surface of boulders and gravel at the bottom of underground streambed. The rock surface was covered by dark brown- black slimy microbial mats likely serving as a food substrate. More specimens were found in flowing stream than semi-stagnant water.

Distribution.

Only known from the type locality.

Conservation status.

The number of known localities (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.

Figures

Plate 6. 1 - 6 Imeretiopsis prometheus sp. nov., Imereti, Kumistavi, Prometheus Cave, specimens used for molecular and anatomical studies. The numbers correspond to individuals, and the letters represent the different views of the same individual. Photograph A. Falniowski.