Phylogenetic Analysis of Crested Newts

We included seven crested newts (see Additional file 2), representing all recognized species, as well as three distinct mitochondrial DNA clades that constitute the T. karelinii group (cf. [16 (link)]). We follow [16 (link)] in awaiting a taxonomic revision of the T. karelinii group before applying specific names to the three constituent mitochondrial DNA clades (the name T. karelinii sensu stricto would apply to the 'eastern clade' and T. arntzeni has been applied to the 'western clade'; no name has as yet been proposed for the 'central clade'). We also sequenced the two marbled newts (T. marmoratus and T. pygmaeus), the remaining members of the genus Triturus, to function as outgroup taxa. Additionally, we added a sequence of Calotriton asper, sister to the genus Triturus, available from [31 (link)] (GenBank accession number EU880307).