Historical biogeography of Tyrrhenian land snails: the Marmorana-Tyrrheniberus radiation (Pulmonata, Helicidae).

University of Siena, Dipartimento di Scienze Ambientali, Via P.A. Mattioli 4, 53100 Siena, Italy.
Molecular Phylogenetics and Evolution (Impact Factor: 4.02). 12/2009; 55(1):26-37. DOI: 10.1016/j.ympev.2009.11.024
Source: PubMed

ABSTRACT The few studies available on Tyrrhenian land snails support high diversification in the Italian Peninsula and groups structured mainly by vicariant events. Here we investigated the phylogeny of a conchologically diversified group of Tyrrhenian land snails assigned to the genera Marmorana and Tyrrheniberus. We constructed a molecular phylogeny by sequencing two commonly used mtDNA genes (cytochrome oxidase I and the large ribosomal subunit). We also carried out conchological and anatomical analysis. Morphological (shell and genitalia) and genetic data (mitochondrial genes) showed paraphyly of Marmorana. Plio-Pleistocene events in the Tyrrhenian area may have structured relationships between species at regional scale while isolation by distance probably played a role in diversification between populations on a local scale. Continental populations experienced dispersal during interglacial periods and fragmentation and reduction during the dry cold climatic phases. Areas inhabited by Apennine Marmorana could represent relict and/or glacial refugia, with extinction in some areas along the Apennines and survival in the south. The results support a reassessment of taxonomy both at genus and species level and call for further analysis.

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