A Megaraptor-like theropod (Dinosauria: Tetanurae) in Australia: support for faunal exchange across eastern and western Gondwana in the Mid-Cretaceous

The fossil record of Australian dinosaurs in general, and theropods in particular, is extremely sparse. Here we describe an ulna from the Early Cretaceous Eumeralla Formation of Australia that shares unique autapomorphies with the South American theropod Megaraptor. We also present evidence for the spinosauroid affinities of Megaraptor. This ulna represents the first Australian non-avian theropod with unquestionable affinities to taxa from other Gondwanan landmasses, suggesting faunal interchange between eastern and western Gondwana during the Mid-Cretaceous. This evidence counters claims of Laurasian affinities for Early Cretaceous Australian dinosaur faunas, and for the existence of a geographical or climatic barrier isolating Australia from the other Gondwanan continents during this time. The temporal and geographical distribution of Megaraptor and the Eumeralla ulna is also inconsistent with traditional palaeogeographic models for the fragmentation of Gondwana, but compatible with several alternative models positing connections between South America and Antarctica in the Mid-Cretaceous

First evidence of ankylosaurian dinosaurs (Ornithischia: Thyreophora) from the mid-Cretaceous (late Albian-Cenomanian) Winton Formation of Queensland, Australia

First evidence of ankylosaurian dinosaurs (Ornithischia: Thyreophora) from the mid-Cretaceous (late Albian-Cenomanian) Winton Formation of Queensland, Australia. Alcheringa 37, 261-269. ISSN 0311-5518. The first evidence of ankylosaurian thyreophorans from the Winton Formation (late Albian-Cenomanian) of central-western Queensland, Australia, reveals new information about the temporal and palaeobiogeographical range of these dinosaurs within Gondwana. The material, which comprises isolated teeth, is the youngest evidence of ankylosaurs in Australia. Although the Winton teeth exhibit a suite of pleisiomorphic characteristics that are also seen in other Australian and Gondwanan ankylosaur taxa, they are morphologically distinct and very likely represent a new taxon. Their discovery adds to the growing body of evidence indicating that thyreophorans, and in particular ankylosaurians, constitute a diverse and important component of Australia's mid-Cretaceous dinosaur fauna