THE origin and relationships of turtles have fascinated and puzzled generations of palaeontologists. Among living amniotes only turtles, crocodiles and mammals have substantial fossil records, extending into the Triassic (200 Myr). These vertebrates have attracted much attention and the broader aspects of crocodilian and mammalian evolutionary relationships are relatively well known. Therefore, it is surprising that the origins and relationships of the Testudines have remained unresolved. Numerous groups of extinct tetrapods1–7have been cited as possible turtle relatives, including the Captorhinidae8–12. New specimens of the small reptile Owenetta from the Upper Permian and Lower Triassic sediments of South Africa provide strong evidence that a group of primitive amniotes, the procolophonids, are the closest sister-group of turtles.