Skeletal morphology and relationships of the early Cretaceous side-necked turtle,Araripemys barretoi(Testudines: Pelomedusoides: Araripemydidae), from the Santana Formation of Brazil

Thirteen new specimens in the collection of the American Museum of Natural History allow redescription of the lower Cretaceous side-necked turtle, Araripemys barretoi Price 1973. Araripemys is one of the three oldest pleurodires known for which the skeletal morphology can be completely described. The genus is incorporated into a phylogenetic analysis of pelomedusid (sensu lato) turtles. Examination of 35 skeletal characters in six living and nine extinct taxa suggest that there are four distinct clades in the Pelomedusidae (sensu lato). These are the Araripemydidae (including Araripemys and an undescribed genus from the same locality), the Pelomedusidae (restricted to the living genera Pelusios and Pelomedusa), the Bothremydidae (including at least five extinct genera) and the Podocnemidae (including the living genera Podocnemis, Peltocephalus and Erymnochelys, and a series of extinct genera). The hyperfamily name Pelomedusoides is available and accommodates these four families.