A Late Cretaceous "tuatara" (Lepidosauria: Sphenodontinae) from South America

摘要: Abstract Rhynchocephalia achieved a global distribution during the Mesozoic but history of sphenodontines, clade containing extant genus Sphenodon (the New Zealand tuatara), remains poorly understood. Here, we describe partial maxilla from Late Cretaceous Argentina bearing teeth that closely resemble those modern Sphenodon. This material helps to fill in notable gap fossil lepidosaurs because it represents first evidence sphenodontine South America and increases number known rhynchocephalian taxa region. The morphological disparity encompassed by these records is consistent with suggestions rhynchocephalians remained diverse despite concurrent disappearance Laurasia. Moreover, new record supports hypothesis sphenodontines were once found widely throughout Gondwana, before its constituent landmasses began separate about 80 million years ago. probably biogeographic remnant this distribution, whether relatively large size ability remain active at cold temperatures reflects high latitude ancestry requires further examination.