Pontohoratia mapeli 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 mapeli Grego & Mumladze sp. nov. Fig. 16E, F ; Plates 20 (6); 21(4); 22(1-4)

Type locality.

Georgia • Samegrelo, Kanti Village near Mukhuri, Mapeli Spring (მაპელის წყარო, სოფელი კანტი); 42°38'23"N, 42°10'08"E; 290 m a.s.l.

Material.

Holotype: Georgia • 1 adult, dry; type locality; 06 May 2018; J. Grego, L. Mumladze and M. Olšavský leg.; ISU FM-T021-H. Paratypes: Georgia • same as for holotype; col. JG F1060/5 dry; • same as preceding; 12 October 2019; J. Grego, L. Mumladze and G. Bananashvili leg.; ISU FM-T021-P1/ 40 dry and 69 wet, SBMNH 635896/6 dry, NHMW 113375/2 dry, HNHM 104684/2 dry, NHMUK 20191340/2 dry, NHMB 563972/2 dry, SMF 358931/2 dry, ZMH 140636/2 dry, MNHN-IM-2016-7900, ZIN 1/503-2020/2 dry, coll. JG F1413/40 dry and 69 wet, coll Glöer /1 dry.

Diagnosis.

The shell of the new species is more flat-discoid with a more open umbilicus, more rounded and proportionally smaller aperture vs. the geographically closest relatives: P. vinarskii sp. nov. and P. pichkhaiai sp. nov. The shell shape is somewhat similar to H. pseudohauffenia , but it can be differentiated by less pronounced protoconch, lower shell height to width ratio the proportionally smaller, more rounded aperture as well by its operculum lacking the knobby sculpture.

Description.

Shell: small, paucispiral, discoid with flat, only slightly pronounced spire and widely opened umbilicus. Diameter 1.37-1.51 mm. The inflated whorls are separated by a deeply cut sulcus. Protoconch surface covered by dense shallow pits. The shell surface whitish and translucent with smooth surface. The aperture round with labral peristome oblique to the columellar axis. The aperture barely attached at its upper columellar side to the body whorl. Protoconch surface covered by raised malleations gradually changing to a regular pitting towards the nucleus.

Operculum: reddish, circular, paucispiral with central nucleus, centrally thickened and elevated inward without peg.

Holotype measurements: H-0.57 mm; W-1.38 mm; BH-0.55 mm; BW-0.95 mm; AH-0.42 mm; AW-0.45 mm; CA: -40°.

Anatomy: the penis (Fig. 16E, F ) proximally broad, with a broad, slightly marked outgrowth on its left side in the median part, and thin filament distally.

Etymology.

Name derived from the name of Mapeli (მაპელი) Spring in Kanti (კანტი) Village, the type locality of the species.

Habitat.

Stygobiotic species. See the habitat of Caucasogeyeria chrysomallos 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.