Phylogeny, species delimitation and population structure of the steppe-inhabiting land snail genus Helicopsis in Eastern Europe

Abstract

Abstract We here study the steppe-inhabiting land snail genus Helicopsis (Gastropoda: Geomitridae: Helicellinae) across Eastern Europe using mitochondrial 16S rDNA sequences and nuclear AFLP markers and compare the biogeographical patterns with those of other steppe-inhabiting organisms. The subdivision of Central and Eastern European Helicopsis reflects the geographical subdivision of the European steppe belt in Pontic, Pannonian and Northern steppes. The subdivision within Helicopsis is deeper, at the species level, than in most other steppe-inhabiting groups. Helicopsis populations from the Pontic steppes can be classified into two sister-species. Helicopsis lunulata includes mainly populations with depressed conical shells previously identified as H. striata, but also populations with disc-like shells previously identified as H. instabilis, and it is distributed mainly west of the Dnieper River. Most Helicopsis populations from east of the Dnieper, especially from Crimea, belong to the variable H. filimargo that includes H. gasprensis, H. retowskii, H. arenosa, H. luganica, H. martynovi and H. subfilimargo. The species inhabiting the Pannonian Basin and the Northern steppes form a well-supported monophylum, including H. hungarica in the Pannonian Basin, H. austriaca at the fringe of the Eastern Alps and H. striata mainly in the Northern steppes.