Molecular phylogeny of the salamandrid genus Neurergus: evidence for an intrageneric switch of reproductive biology

A molecular phylogeny of the salamandrid genus Neurergus was reconstructed based on two sections of the 12S and 16S mitochondrial ribosomal genes (810 bp), 19 allozyme and three plasma protein loci. When representative species of all closely related salamandrid groups were included, mitochondrial data provided evidence for monophyly of Neurergus within the Salamandridae. Mitochondrial and allozyme data showed homogenous intrageneric tree topologies, but different estimates of times of separation. We calibrated the evolutionary rate to 0.46% pairwise sequence divergence per million years. Accordingly Neurergus diverged 18 million years ago (mya) from a lineage that comprised Euproctus asper and large bodied newts of the genus Triturus. A split around 11 mya produced two major clades within Neurergus. Further separation within the southern ‘N. crocatus-clade’ (comprising N. crocatus, N. microspilotus and N. kaiseri) occurred ca. 5 mya. The northern ‘N. strauchii-clade’ separated into N. s. strauchii and N. s. barani ca. 3 mya. Our molecular phylogeny indicates that stream-reproduction is the ancestral state for Neurergus, adaptations to pond-reproduction in N. kaiseri are the result of an evolutionary switch of reproductive biology within the ‘N. crocatus-clade’.