Caucasogeyeria colchis 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

Caucasogeyeria colchis Grego & Mumladze sp. nov. Plates 15 (2-4); 17(1, 2)

Type locality.

Georgia • Samegrelo, Pirveli Balda, Motena Cave; 42°28'36"N, 42°23'29"E; 480 m a.s.l.; sediment in terminal lake.

Material.

Holotype: Georgia • 1 adult dry; Type locality; 09 May 2018; J. Grego, L. Mumladze and M. Olšavský leg.; ISU FM-T002-H. Paratypes: Georgia • same as for holotype; coll. JG T1036/1 dry; • Samegrelo, Pirveli Balda (პირველი ბალდა), spring in village above road; 42°29'2"N, 42°23'53"E; 295 m a.s.l.; 09 May 2018; J. Grego, L. Mumladze and M. Olšavský leg.; ISU FM-T002-P1/12 dry, SBMNH 633068/4 dry, NHMW 113362/1 dry, coll. JG F1034/12 dry. • same as preceding; same as preceding; 12 October 2019; J. Grego leg.; ISU FM-T002 P2/5 dry, HNHM 104676/1 dry, NHMB 563962 /1 dry, SMF 358923/1 dry, coll JG F1434/37 dry. Other material: Georgia • Imereti, Nakhriduri 6, left tributary rivulet under travertine waterfall; 42°29'7"N, 42°31'22"E; 960 m a.s.l.; 03 May 2018; J. Grego, L. Mumladze and M. Olšavský leg.; coll. JG/4 dry.

Diagnosis.

The C. colchis sp. nov. differs from all the members of the genus by its more deeply cut sinuation at the junction of the labral margin with the body whorl. The sinulus-like deep grove and the characteristically inward bent labral fold clearly distinguish the species from its congeners. From C. pseudocolchis sp. nov. it can be distinguished mainly by shallower and narrower sinulus-like cut at the posterior canal, by the differently curved columellar peristome, different sinuation of the labral margin and by proportionally larger body whorl.

Description.

Shell: conical, elevated 1.35-1.80 mm high shell with 4½ inflated whorls and a deeply cut suture. Shell colour milky white with frequent reddish-brown inorganic encrustations. Umbilicus widely open. The expanded, rhomboidal aperture with a characteristic deep and broad sinus-like cut at the adapical labral junction with the body whorl. The protruded labral fold characteristically curved inward, continuing to a negative sinuation at the lower extremity of the aperture. Columellar margin just slightly positively sinuated. Protoconch surface regularly pitted.

Operculum: white, glassy translucent, circular and paucispiral with excentric nucleus.

Animal body: entirely white, without eyes and bears, very long tiny tentacles (Plate 12 (5-8)).

Holotype measurements: H-1.80 mm; W-1.40 mm; BH-1.15 mm; BW-1.10 mm; AH-0.85 mm; AW-0.65 mm; CA: 37°.

Anatomy: not known.

Etymology.

Named after the ancient kingdom Colchis (კოლხეთი) established in the territory of the southwestern Caucasus and the Colchis lowland from the 13th century BC to 164 BC.

Habitat.

Stygobiotic species. The scarce empty shells were found in the terminal sump lake of Motena Cave, and a few live individuals with some empty shells in the head of Pirveli Balda spring as it emerges from stone debris.

Distribution.

Except the type locality and the Motena Cave, the species is known from one locality in the Turchu Gamosadivari basin.

Conservation status.

The number of known locations (3) 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 species is sympatric with the C. gloeri sp. nov. in Nakhriduri 2 spring in the Turchu Gamosadivari Basin, Imereti and in Motena Cave and Piveli Balda spring in Samegrelo. Both species can be clearly separated by shell morphology without intermediates, indicating their separate specific position. Separation is confirmed by a p-distance = 0.034 in the H3 gene.

Figures

Plate 12. Caucasogeyeria specimens used for molecular and anatomical studies 1 C. chrysomallos sp. nov. 2 - 4 C. ignidona sp. nov. 5 - 8 C. colchis sp. nov., live specimens Pirveli Balda, spring in the village 9 - 12 C. chrysomallos sp. nov. The numbers correspond to individuals. Photograph A. Falniowski, J. Grego, 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.