Morphometrics of the yellow-bellied toad (Bombina variegata) in the Central Balkans: Implications for taxonomy and zoogeography

A comprehensive survey of the Central Balkan yellow-bellied toad (Bombina variegata) populations was undertaken to describe morphometric differentiation between 4 geographic groups previously demarcated by molecular studies. Our analyses confirmed pronounced geographic structuring at the population level, as well as a clear transition over a relatively short distance separating the localized B. v. scabra, endemic to the Balkans, and the widely distributed B. v. variegata. We present the inferred range boundaries of these geographic groups in the Central Balkans, and discuss their historical zoogeography and taxonomy. Our study provides evidence that the Northern Balkans, a secondary transition zone of postglacial origin, constitutes an important European suture area for amphibians.nul