The oldest-known primate skeleton, 62-million-years-old, dwelled in treetops, not on the ground, according to a new analysis.The study shows that Torrejonia, a small mammal from an extinct group of primates called plesiadapiforms, had skeletal features adapted to living in trees, such as flexible joints for climbing and clinging to branches. Previously, researchers had proposed that plesiadapiforms in Palaechthonidae, the family to which Torrejonia belongs, were terrestrial based on details from cranial and dental fossils consistent with animals that nose about on the ground for insects.