Tiny guardian of the spring: Description of the first Islamiinae (Mollusca, Hydrobiidae) from the Caucasus

Gveleshapia kvevri gen. et sp. nov. represents the first formally described species of Islamiinae from the Caucasus, extending the distribution of this subfamily far beyond its traditionally outlined Mediterranean range. The new taxon was discovered during fieldwork in 2021–2022 in Mandaeti village, Imereti, Georgia. Morphological examination of seven ethanol-preserved specimens and six empty shells, combined with phylogenetic analysis, confirms its distinct taxonomic status.

The genus is characterized by an elongate-conical shell with up to 5.2 whorls, trilobate penis morphology, and the absence of a bursa copulatrix in the female reproductive system. Phylogenetic reconstruction places Gveleshapia kvevri sp. nov. within a highly supported clade as sister to Islamia valvataeformis (Möllendorff, 1873) and Alzoniella braccoensis Bodon & Cianfanelli, 2004. The species is known from two spring localities 1.7 km apart, confirming its critically restricted stygobiont distribution.

The findings highlight the taxonomic instability of Islamiinae, which appears paraphyletic in molecular analyses; the Caucasian lineage of Gveleshapia kvevri sp. nov. further underscores the need for a comprehensive systematic revision. The localized distribution and anthropogenic pressures warrant conservation consideration.