Taxonomic assessment and distribution of common toads (Bufo bufo and B. verrucosissimus) in Turkey based on morphological and molecular data

The Bufo bufo species group includes four species distributed in the western Palearctic: B. bufo, B. eichwaldii, B. spinosus and B. verrucosissimus. Both B. bufo and B. verrucosissimus are known to occur in Turkey, but their range boundaries and the taxonomic status of B. verrucosissimus are still uncertain. In this study, we analyzed the variation in a set of morphological characters and in two mitochondrial and two nuclear DNA markers to address these questions. Phylogenetic analyses of sequence data support two main clades of common toads in Turkey, corresponding to B. bufo and B. verrucosissimus. The latter is subdivided into two allopatric subclades including populations along the Mediterranean and Black Sea coast, respectively. Discriminant analysis of morphological data showed separation among groups as defined by molecular analyses. We discuss these results and their implications for the evolutionary history of common toads in Turkey.