A mitochondrial DNA phylogeny of the endangered vipers of the Vipera ursinii complex

► Newly discovered vipers in Romania phylogenetically are Vipera ursinii rakosiensis. ► They thus represent its third known population and the only one outside Hungary. ► V. u. moldavica is the sister subspecies and includes vipers from the Danube Delta. ► Lowland/montane divergence occurred independently in V. ursinii and V. renardi. ► Colonization of montane habitats occurred several times in V. renardi.