Pontohoratia pichkhaiai 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

Pontohoratia pichkhaiai Grego & Mumladze sp. nov. Plates 20 (3); 21(2); 22(5-8); Fig. 16C, D

Type locality.

Georgia • Samegrelo, Mukhuri, Shisha Spring (შიშა წყარო, სოფელი მუხური); 42°37'47"N, 42°11'26"E; 255 m a.s.l.; sediment at bottom of spring zone.

Material.

Holotype: Georgia • 1 adult, dry; type locality; 10 May 2018; J. Grego, L. Mumladze and M. Olšavský leg.; ISU FM-T022-H. Paratypes: Georgia • same as for holotype; ISU FM-T022-P1/9 dry, coll. JG F1044/9 dry; • same as for holotype; 11 October 2019; J. Grego, L. Mumladze and G. Bananashvili leg.; ISU FM-T022-P2/13 dry SBMNH 633083/1 dry, NHMW 113376/1 dry, HNHM 104685/1 dry, NHMB 563973/1 dry, SMF 358933/1 dry, ZMH 140637/1 dry, MNHN-IM-2016-7901, ZIN 1/504-2020/1 dry, coll. JG F1419/14 fry, coll. Glöer /1 dry.

Diagnosis.

The new species differs from the geographically close P. vinarskii sp. nov. by its flatter shell and smaller, more rounded aperture. P. mapeli has a flatter shell with smaller, more rounded aperture.

Description.

Shell: planispiral small, discoid, the spire only a slightly pronounced and early whorls flat, umbilicus widely opened and protoconch surface pitted. Diameter 1.36-1.68 mm. The descending whorls separated by a deep suture. The shell wall is translucent, the surface whitish and smooth. The aperture proportionally small and circular with the labral peristome angled vs. the columellar axis. The aperture in a short distance joining the body whorl. Protoconch surface weakly pitted in its nuclear portion and abapically gradually changing into a smooth slightly malleated surface.

Operculum: reddish, circular, paucispiral, with central nucleus and smooth central callosity without forming a peg at its attachment.

Holotype measurements: H-0.87 mm; W-1.42 mm; BH-0.66 mm; BW-1.00 mm; AH-0.50 mm; AW-0.5 mm; CA: -45°.

Anatomy: the penis (Fig. 16C, D ) simple, without any outgrowths, broad, slowly narrowing to its distal end.

Etymology.

Named after the avid speleologist Igor Pichkhaia (იგორ ფიჩხაია) from Chkhorotsku, who supported our research in the region of Samegrelo (Mingrelia).

Habitat.

Stygobiotic species. Empty shells and a few live individuals were found washed out from primary habitat at the bottom sediments of the spring lake of Shisha spring near Mukhuri. See the habitat of Kartvelobia shishaensis sp. nov.

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.

Figures

Figure 16. A, B Pontohoratia vinarskii sp. nov.: Samegrelo, Chkhorotsku, Nazodelavo Cave, morphology of penis C, D P. pichkhaiai sp. nov.: Samegrelo, Chkhorotsku, Shisha Spring, morphology of penis E, F P. mapeli. sp.: Samegrelo, Kanti, Mapeli Spring, morphology of penis. Photograph A. Falniowski and A. Rysiewska; drawing A. Falniowski.

Plate 20. 1, 2 Pontohoratia vinarskii sp. nov., Samegrelo, Chkhorotsku, Letsurtsume, Letsurtsume Cave: 1 holotype 2 paratype 3 P. pichkhaiai sp. nov., Samegrelo, Mukhuri, Shisha Spring, holotype 4 Hausdorfenia pseudohauffenia sp. nov., Racha, Zemo Krikhi, Krikhula Spring, holotype 5 H. shareula sp. nov., Racha, Nikortsmintha, Tsivtskala 2 Spring near power station in the Shareula valley, holotype 6 P. mapeli sp. nov., Samegrelo, Mukhuri, Kanti, Mapeli Spring, holotype 7 H. pseudohauffenia sp. nov., Racha, Zemo Krikhi, Krikhula Spring; aberrant specimen 8, 9 P. vinarskii sp. nov., Samegrelo, Chkhorotsku, Letsurtsume, Letsurtsume Cave: 8 morphotype 9 live specimen with marked carbonate incrustations. The numbers correspond to individuals, and the letters represent the different views of the same individual. Photograph J. Grego.