The Biochronology and Palaeobiogeography of (Crocodylia: Mekosuchinae) Based on New Specimens from the Northern Territory and Queensland, Australia

New records of the Oligo-Miocene mekosuchine crocodylian, , from Queensland and the Northern Territory are described. and are accepted as valid species in the genus and their diagnoses are revised. Both species are present in Queensland and the Northern Territory but are restricted in time, with known from the late Oligocene and from the middle Miocene. The broad geographic distributions and restricted time spans of these species indicate that this genus is useful for biochronology. The record of from the Pwerte Marnte Marnte Local Fauna in the Northern Territory establishes that the species inhabited the north-western margin of the Lake Eyre Basin (LEB) drainage system. More southerly Oligo-Miocene sites in the LEB contain only one crocodylian species, . The Pwerte Marnte Marnte occurrence of indicates that the separation of and did not correspond with the boundaries of drainage basins and that palaeolatitude was a more likely segregating factor.