Speciation in rock-dwelling land snails: Understanding the origin of diversity using Montenegrina as a model system
In terms of the geographical range we are broadening the area of interest towards the Balkans. The high species diversity, the large number of narrow-range endemic taxa as well as the close historical biogegraphical relationships with the Alpine fauna makes it a promising area for biodiversity research.
The Balkans, like some other limestone dominated biodiversity hotspots in the World, has a very rich obligate rock-dwelling mollusc fauna. However, relatively little is known about the factors and processes that contribute to the development and maintanence of this fascinating diversity. During our FWF funded project – ’Speciation in rock-dwelling land snails: Understanding the origin of diversity using Montenegrina as a model system (FWF P 26581-B25)’ – we will use this door-snail (clausiliid) genus to gain insight into the speciation of obligate rock-dwelling gastropods in general.
Montenegrina is distributed in the western part of the Balkan Peninsula (Montenegro, Macedonia, Greece and Albania). Like other obligate rock-dwelling animals, Montenegrina populations live on bare limestone cliff surfaces or under limestone rocks. Due to the patchy distribution of this special habitat type, the genus comprises several small range endemic taxa; according to the current Fauna Europaea system (Bank 2012), there are 88 known subspecies (which are classified into 22 species). Moreover, due to the intensive fieldwork activity of the past decade there are several recently discovered populations, some of which are presumed as new taxa and are to be described. This reflects extremely high rate of endemism as the number of known populations (based on literature records and museum collections) can be between 350 and 500.
The systematics of this taxon-rich group, as of almost every rock-dwelling gastropod group in the Mediterranean region, was almost exclusively set-up on a conchological basis. Our preliminary molecular studies, however, revealed that most of the conchological traits, which were considered taxonomically important, show morphological convergence and many ‘species’ in the current system seem to be paraphyletic. As a first step, therefore, a taxonomic revision is necessary which will be based on a sound phylogenetic footing. After this, we will be able to investigate the distribution history, character evolution and niche divergence on a strong molecular phylogenetic basis.
DNA markers that we already applied with success in our earlier studies will be used – the “long” fragment of the ribosomal rRNA genes (large subunit 16S rRNA, small subunit 12S rRNA), the COI gene and a nuclear region that involves partly the histone H3 and H4 genes with a spacer region in between.