Abstrakt
Populations of rock-dwelling snails are often isolated from each other due to outcrops of suitable rock forming islands separated by uninhabitable habitats. By chance, some snail taxa were able to rapidly extend their distribution ranges or colonise distant areas.
The helicid Levantina from the Middle East has a very large range compared with related rock-dwelling genera. We present here the first comprehensive molecular phylogeny of Levantina suggesting that its range is not extended due to Levantina being an old taxon, but rather as a result of a rapid expansion, probably during the Pliocene.
These snails originated in the south-east of present-day Turkey, from where they colonised the Levant, the Asir Mountains in Saudi Arabia, the Alborz Mountains and the Central Taurus as well as the island of Cyprus. Eventually, these snails also reached the south-eastern Aegean region by several independent expansion events.
In particular, the Arabian species are not closely related to those from the Levant as previously presumed, but are sister to one of the species from south-eastern Turkey. The occurrence of a Levantina spiriplana complex in the Aegean is most likely a result of intentional transport of these edible snails, as all three lineages found there originated from the Levant.
Our results further suggest that the species-level taxonomy of the genus needs an integrative revision.