abstract
| - Ozraptor ("Australian thief") was an abelisaurian dinosaur that lived during the Middle Jurassic period of Australia. Only known from one partial leg bone, Ozraptor is difficult to classify. When first discovered in 1967, the bone was thought to belong to a turtle. Re-evaluation of the bone by Long and Molnar(1998) showed that it was actually some sort of theropod. Another study by Rauhut (2005) suggested that it was indeed a theropod, and more specifically, an abelisaur. The type (and only known) species is O. subotaii. In 1998 Long and Molnar named and described the type (and only) species Ozraptor subotaii. The generic name is derived from "Ozzies", the nickname for Australians, and a Latin raptor, "seizer". The specific name honours a fictional character, the swift-running thief and archer "Subotai" from the movie Conan the Barbarian.[3] The holotype, UWA 82469, was found from layers of the Colalura Sandstone Formation, dating to the middle Bajocian, about 170 million years old. It consists of the distal or lower end of a left tibia. Together with Rhoetosaurus, Ozraptor belongs to the oldest known Australian dinosaurs. The specimen is eight centimetres long and four centimetres wide at the lower end. From this a total length for the shinbone was estimated of about seventeen to twenty centimetres and for the animal as a whole of about two metres. Three diagnostic features were established enabling it to be upheld as a distinct species of dinosaur: the ascending process of the astragalus had a rectangular shape with a straight upper end; the astragalar facet had a vertical ridge; the medial condyle was weakly developed. Only known from one partial leg bone, Ozraptor is difficult to classify. In 1998 the describers could not more precisely determine the classification than a Theropoda incertae sedis. In 2004 Thomas Holtz thought it was a member of the Avetheropoda. In 2005 another study, by Oliver Rauhut, suggested that it was indeed a theropod, and more specifically, a member of the Abelisauroidea based on the presence of the distinct vertical median ridge on the astragalar groove.[4] If so, it would be the oldest known abelisauroid.
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