Mesozoic taxonomic orders

Rhynchocephalia (; ) is an order of lizard-like reptiles that includes only one living species, the tuatara (Sphenodon punctatus) of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a speciose group with high morphological and ecological diversity. The oldest record of the group is dated to the Middle Triassic around 244 million years ago, and they had achieved global distribution by the Early Jurassic. Most rhynchocephalians belong to the suborder Sphenodontia ('wedge-teeth'). Their closest living relatives are lizards and snakes in the order Squa