For Immediate Release Media contact: The Field Museum Nancy O'Shea 312/665-7100 media@fieldmuseum.org Similarities between dinosaur fossils in Argentina and Australia generate the surprising conclusion that dinosaurs roamed across eastern and western Gondwana during the Cretaceous. Nathan Smith, a Field Museum paleonologist and University of Chicago graduate student, is the lead author on research published online by the journal "Proceedings of the Royal Society of London, B" on June 11, 2008. Here is how Smith summarizes the research: We describe dinosaur remains from the Early Cretaceous of Australia that share unique features with Megaraptor, a large predatory dinosaur otherwise only known from Argentina. This material (see attached image) represents the first Australian carnivorous dinosaur with unquestionable affinities to animals from other Southern Hemisphere continents. It indicates that faunal interchange occurred across Gondwana, a landmass formed by the coalesced southern continents, during the Cretaceous. This conclusion counters longstanding claims of Northern Hemisphere affinities for Cretaceous Australian dinosaurs, and of geographic/climatic isolation of Australian faunas from other Gondwanan faunas. Our results are consistent with several geological models for rifting between the southern continents. The title of the paper is: A Megaraptor-like theropod (Dinosauria: Tetanurae) in Australia; support for faunal exchange across eastern and western Gondwana in the mid-Cretaceous. It is authored by Smith, N. D., P. J. Makovicky, F. Agnolin, M. Ezcurra, D. Pais, and S. Salisbury. A copy of the paper and digital images are available. << Return to the Press Room