The molecular systematics and biogeography of the European cobitids based on mitochondrial DNA sequences.

Phylogenetic inference regarding the biogeography and evolution of the family Cobitidae depends in large part on the correct interpretation of transitions between the morphological states of secondary sexual characters (e.g., the scale of Canestrini or lamina circularis). Here, we use the complete mitochondrial ATP synthase 8 and 6 and cytochrome b genes to provide an independent assessment of systematics and biogeographic relationships of species in the genus Cobitis, including geographic and subgeneric sampling of species with Canestrini's scale present, duplicated, or absent. The mtDNA-based phylogeny for the genus Cobitis provides the first formal hypothesis for the group and permits a phylogenetic-based assessment of the morphological transitions demonstrated by Canestrini's scale. Our data confirm the monophyly of the genus Cobitis and indicate that European Cobitis comprise six evolutionarily independent lineages. These lineages were defined by nucleotide synapomorphies permitting bootstrapped confidence estimates of 95% or greater and mtDNA genetic distances greater than 4.5% and correspond with moderate fidelity to the Cobitis groups defined by Bacescu (1962, Rev. Roum. Biol. 4, 435-448). The Caucasian lineage, C. cf. sibirica, represents the basal sister species of the genus Cobitis, supporting an eastern Asiatic origin of the European Cobitis: Cobitis sensu stricto, Acanestrinia, Bicanestrinia, Iberocobitis, and Cobitis calderoni. Phylogenetic relationships among Cobitis subgenera and species indicate that the ancestral condition of one scale of Canestrini was duplicated once at the origin of the Bicanestrinia lineage and has been independently lost by C. calderoni and C. elongata. The absence of the scale of Canestrini is the synapomorphy defining the subgenus Acanestrinia, but the mtDNA phylogeny indicates that Acanestrinia is not a natural group and places C. calderoni as the sister lineage to the subgenus Iberocobitis, a finding that is also geographically parsimonius.