A new genus and species of Hydrobiidae Stimpson, 1865 (Caenogastropoda, Truncatelloidea) from Peloponnese, Greece

Minute caenogastropod brackish-water gastropods, formerly classified as Hydrobia, are important elements of the brackish-water fauna and were objects of intensive study for many years. Until now, five genera have been distinguished, most of them represented by a number of species, but rather indistinguishable without molecular data (cytochrome oxidase subunit I - COI). In the eastern Mediterranean region, they are still poorly studied. In this paper, we present a new species of Hydrobia from the brackish Moustos spring, Arkadia, eastern Peloponnese, Greece. The shell, protoconch, radula, female reproductive organs, and penis are described and illustrated, together with the molecular (COI) relationships with other hydrobiids. All data confirm that these snails represent a distinct taxon, which must be classified as a new species belonging to a new genus. The formal descriptions are given. The closest, sister taxon is Salenthydrobia Wilke, 2003. The molecularly estimated time of divergence, 5.75 +/- 0.49 Mya, coincides with 5.33 Mya, which is the time of the Oligocene flooding that terminated the Messinian salinity crisis. During the latter period, brackish Lago-Mare habitats were most probably suitable for the last common ancestor of Salenthydrobia and the newly described genus. Later, the Pliocene flooding isolated the Apennine and Peloponnese populations, promoting speciation.

Automated summary

This paper presents a new species of Hydrobia from the brackish Moustos spring in Arkadia, Greece. Through examination of reproductive organs and molecular relationships, it is confirmed as a new genus and species. The origin of this species is related to the Messinian salinity crisis and speciation was promoted during the Pliocene flooding.