Polar dinosaurs and biotas of the Early Cretaceous of southeastern Australia

Southern polar biotas of the Early Cretaceous (Valanginian-early Albian) of south-central Victoria, Australia, contain > 150 taxa of plants, invertebrates, and vertebrates, including dinosaurs, fish, possibly a labyrinthodont amphibian, turtles, lepidosaurs, pterosaurs, freshwater plesiosaurs, theropods, and birds, but thus far no crocodiles or mammals. The fossil-producing sediments are the Otway and Strzelecki Groups, which some authors combine into one unit, the Korumburra Group. They represent volcanogenic clays, silts, and sands deposited in several different facies of braided river systems that occupied a down-dropped graben created when Australia and Antarctica began to separate in the late Mesozoic. Periodicity in the sedimentation regime may have been related to meltwater floods in the austral spring. Invertebrates, plants, and geochemistry suggest that a cool, humid climate prevailed. paleomagnetic studies on the Otway Group indicate that southern Victoria was situated at a high latitude, between 70 and 85° south, in the late Early Cretaceous. -from Authors