Late Cretaceous reptiles (Families Elasmosauridae and Pliosauridae) from the Mangahouanga Stream, North Island, New Zealand

Abstract Incomplete reptile specimens from rocks of Piripauan‐Haumurian age (Campanian‐Maastrichtian), that represent the first records of elasmosaurs and pliosaurs from the North Island of New Zealand, are described. Present among the remains is the first elasmosaur cranial material (both adult and juvenile) known from New Zealand. This has been described as a new genus and species of elasmosaur, Tuarangisaurus keyesi . The first North Island record of Mauisaurus haasti is also described. Many specimens, only identifiable to Family, are described as they provide the first record of certain skeletal elements from New Zealand and good comparative material for future studies. The pliosaur remains, identifiable to Family only, provide better preserved material than has so far been known from the New Zealand fossil record.