Sitnikovia megruli, Chertoprud & Palatov & Vinarski, 2020

Chertoprud, E. M., Palatov, D. M. & Vinarski, M. V., 2020, Revealing the stygobiont and crenobiont Mollusca biodiversity hotspot in Caucasus: Part II. Sitnikovia gen. nov., a new genus of stygobiont microsnails (Gastropoda: Hydrobiidae) from Georgia, Zoosystematica Rossica (China) 29 (2), pp. 258-266 : 260-263

publication ID

https://doi.org/10.31610/zsr/2020.29.2.258

publication LSID

urn:lsid:zoobank.org:pub:E08FB2A0-AC73-418B-9732-FC73D80411A8

persistent identifier

https://treatment.plazi.org/id/767B87AC-F523-DE30-FCED-FAC952EEFCDE

treatment provided by

Felipe

scientific name

Sitnikovia megruli
status

sp. nov.

Sitnikovia megruli View in CoL sp. nov.

( Figs 3a, 3c, 4a, 4c, 4e, 4g, 4i)

Paladilhiopsis View in CoL ” sp.: Chertoprud et al., 2020: 275–289.

Holotype. Adult mollusc, Georgia, Samegrelo-Zemo Svaneti, Chkhorotsqu district, Odishi plain, left side of the Bulebe River , subterranean spring inside Garakha Cave , 42°31′7.91″N 42°10′6.54″E, 207 m a.s.l., 03.II.2017, leg. D. Palatov, No. 514/1 ( ZIN). GoogleMaps

Paratypes. 21 adult molluscs, same collecting data as for the holotype, five under No. 514/2 ( ZIN), three under No. Lc-40753 ( ZMMU) and the rest in collections of the authors GoogleMaps .

Shell dimensions of the holotype (mm). WN 4.75; SH 2.1; SW 1.15; BWH 1.15; BWW 1.0; AH 0.75; AW 0.65. For morphometric characteristics of the entire type series see Table 1.

E.M. Chertoprud et al. Sitnikovia , a new genus of snails from Georgia

Description. Shell small (SH <2.25 mm), high conical, relatively narrow and slender (SW/ SH ratio 0.45–0.60), whitish. Whorl number up to 5.00. Whorls rounded and visibly convex, separated by deep oblique suture. Spire high, its height 0.60 SH or more. Body whorl high and moderately inflated, its width slightly exceeds width of penultimate one. Tangent line slightly convex. Aperture ovate, with obtuse angle in its upper part, more or less detached from body whorl wall forming a rather wide umbilicus. Shell surface almost smooth, with rare growth lines. Protoconch broad, low domed, consists of 1.5 whorls (330 µm in diameter, WE 220 µm). Surface of protoconch covered by mesh-like microsculpture with cellular pits of variable density. Pits of irregular shape, evenly immersed in protoconch surface. Protoconch separated from teleoconch by distinct and thin axial line. Operculum ( Fig. 4i) ovate, corneous, thin, flat, without protrusions on inner side, paucispiral with submarginal nucleus, generally orange or yellowish.

Radula ( Fig. 4g). Two basal cusps on each side of rachis and five cusps on each side of median cusp of rachis. Median cusp only slightly longer than adjacent ones, all cusps relatively long and narrow. On lateral tooth, there are four-five cusps on each side of largest cusp (formula: (5)4-1-4), all cusps long and narrow like those of rachis. Inner marginal tooth with 21–24 cusps, outer marginal tooth with 16 cusps.

Penis ( Fig. 3c) with well-developed dorso-lateral lobe looking as short, conical, obtusely terminated process. Distal pointed part of penis very short and wide.

Animal blind.

Differential diagnosis. This species is similar to S. ratschuli sp. nov., except for being smaller (SH does not exceed 2.2 mm) and having a relatively narrower shell (SW/SH ratio 0.45–0.57). Body whorl is smaller and moderately inflated. Shell proportions are noticeably slenderer. Aperture is relatively small with similar proportions. The protoconch of S. megruli sp. nov. is noticeably bigger than that of S. ratschuli sp.nov. ( Figs 4e, 4f). Surface of protoconch has a similar mesh-like sculpture, although its pattern is slightly different: pits are irregularly shaped and equally impressed. The penial lobe in S. megruli sp. nov. is elongated and narrow, whereas in S. ratschuli sp.nov. it is rather shorter and swollen. There are no noticeable differences in radular morphology between S. megruli sp.nov. and S. ratschuli sp. nov.

Etymology. Named after Samegrelo (Georgian სამეგრელო), a historic province in the western part of Georgia.

Distribution. Endemic to Western Georgia. Known only from the type locality.

Habitats and ecology. Inhabits a subterrane- an spring in Garakha Cave ( Fig. 3e), prevailing on solid substrates. The densest aggregations of snails were found in the small left tributary of the main cave stream. Molluscs were collected from the submerged stones and from the surface of rimstone pools. Water indicators: T 11 °C, pH 8.5, total dissolved solids ( TDS) 130 ppm.

ZIN

Russian Academy of Sciences, Zoological Institute, Zoological Museum

ZMMU

Zoological Museum, Moscow Lomonosov State University

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Littorinimorpha

Family

Hydrobiidae

Genus

Sitnikovia

Loc

Sitnikovia megruli

Chertoprud, E. M., Palatov, D. M. & Vinarski, M. V. 2020
2020
Loc

Paladilhiopsis

Chertoprud E. S. & Borisov R. R. & Palatov D. M. & Marinskiy V. V. & Krylenko S. V. & Kovacheva N. P. & Pichkhaia I. 2020: 275
2020
Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF