Molecular phylogenetics of the mud and musk turtle family Kinosternidae.

The turtle family Kinosternidae comprises 25 living species of mud and musk turtles confined to the New World. Previous attempts to reconstruct a phylogenetic history of the group have employed morphological, isozyme, and limited mitochondrial DNA sequence data, but have not been successful in producing a well-resolved phylogeny. With tissues from every recognized species and most subspecies, we sequenced three mitochondrial (cyt b, 12S, 16S) and three nuclear markers (C-mos, RAG1, RAG2). Our analyses revealed the existence of three well-resolved clades within the Kinosterninae (aged >22 mya), only two of which have been named: Sternotherus and Kinosternon. We here describe the third clade as a new genus. The evolutionary relationships among most species were well resolved, although those belonging to the K. scorpioides species group will require more extensive geographic and genetic sampling. Divergence time estimates and ancestral area reconstructions permitted the development of the first rigorous hypothesis of the zoogeographic history of the group, including support for three separate dispersals into South America, at least two of which preceded the closure of the Panamanian portal.