colder areas in plesiosaurs. Several Late Cretaceous oceanic plesiosaurs and mosasaurs have been discovered in New Zealand and Antarctica, with some, such as Mauisaurus, being endemic, while others, such as Prognathodon, having a cosmopolitan distribution. Elasmosaurs and pliosaurs are known from one to three species from this area. The discovery of three cryptoclidids in the Southern Hemisphere–Morturneria from Antarctica, Aristonectes from South America, and Kaiwhekea from New Zealand–indicates a diversification of the family in the Late Cretaceous of this region and perhaps an increasing productivity of the early Southern Ocean. Pterosaurs Two clades of pterosaurs are represented in Early Cretaceous Australia, Pteranodontoidea and Ctenochasmatoidea, remains mainly deriving from the Toolebuc Formation and areas of Queensland and New South Wales. It is thought that at least six pterosaur taxa existed in Cretaceous Australia, however, given the fragmentary nature of the remains, many fossils recovered originate from undetermined pterosaur. Fossils were found in shallow-water environments and lagoons, indicating a diet of fish and other aquatic life. The ctenochasmatids were the only archaeopterodactyloids to survive into the Cretaceous. The only pterosaur tooth remains discovered in Australia deriving from the Early Cretaceous belong to Mythunga and a possible Late Cretaceous anhanguerid. Mythunga is estimated to have had a wingspan, much larger than any other archaeopterodactyloid discovered, though it is possible the pterosaur is more related to the Anhangueridae or Ornithocheiridae. However, pterosaur remains existing in what were the non-polar regions of Australia, given their ability to migrate by air, perhaps did not need to cross a land bridge through the polar regions to arrive there, meaning they did not ever inhabit the South Polar region. Of the Late Cretaceous pterosaurs, only the remains belonging to the family Azhdarchidae–found in the Carnarvon and Perth basins in Western Australia–were assigned to a taxon. A possible representative of Ornithocheiridae was found in Late Cretaceous Western Australia, though the family was previously thought to have gone extinct in the Early Cretaceous. Mammals Seven mammals have been discovered from Early Cretaceous Australia: an undescribed ornithorhynchid, Kryoryctes, Kollikodon, Ausktribosphenos, Bishops, Steropodon, and Corriebaatar; all of which were endemic to Australia during this time. It is likely mammals crossed the Antarctic land bridge between Australia and South America in the Early Cretaceous, and likely the ancestors of the endemic mammals of Australia arrived during the Jurassic across the supercontinent Pangaea. Invertebrates Several fossils of insects and crustaceans are known from South