Australovenator wintonensis is Australia's most complete theropod dinosaur. The skeleton consists of two nearly complete forelimbs and hind limbs, along with isolated ribs, gastralia and both dentaries. A. wintonensis stood about 1.6 metres at the hip and was approximately 5 metres in length. The fossils were discovered amongst the remains of a sauropod dinosaur Diamantinasaurus matildae. Why the two specimens were preserved together is still unknown.
ETYMOLOGY: Winton's Southern Hunter
GEOLOGY: Winton Formation, central western Queensland
AGE: Earliest Late Cretaceous (Cenomanian) 98–95 million years ago
A. wintonensis was discovered in 2005 and published in 2009.
A. wintonensis was originally recognised as a Tetanuran theropod as it possessed traits from both Allosauroidea and Carcharodontosauria and later was placed within a clade named Neovenatoridae, which included Aerosteon riocoloradensis, Megaraptor namunhuaiquii, Orkoraptor burkei, Fukuiraptor kitadaniensis, Chilantaisaurus tashuikouensis and Neovenator salerii. A review of the evolution of Gondwanan carnivorous dinosaurs during the Cretaceous was undertaken by Novas et al. A new family Megaraptoridae was established to represent the Gondwanan megaraptorans, A. wintonensis, A. riocoloradensis, M. namunhuaiquii, O. burkei and F. kitadaniensis recovered as the immediate sister taxon of this clade. Additionally these theropods were identified as being deeply nested within Coelurosaurian lineages rather than Allosauroidea and was suggested to share close affinities with the Asiamerican Tyrannosauridae.
Left: the holotype dentary of Australovenator wintonensis. Middle: a lateral view of the manus of Australovenator wintonensis. Right: Australovenator gastralia being prepared, 2013.
A. WINTONENSIS AND D. MATILDAE DEATH SCENE THEORIES
Although it was originally hypothesised that A. wintonensis and D. matildae were drowned in a flood event and washed up beside each other, recent observations reveal that this was very unlikely due to the fact that both skeletons were preserved in sediments deposited by still water. Animals that become victims of a flood today are very rarely found in low lying areas within the flood zone due to the action of flood waters that force large, floating masses out of the fast-flowing watercourse area into the shallow, slow moving current along its outer reaches. Once out of the fast-flowing flood zone, the carcass becomes grounded in shallow water and, as the flood recedes, is left high and dry where it breaks down and weathers away. The most likely explanation is that "Matilda" became trapped in the deep, sticky clay/mud sediments of a drying waterhole similar to sheep and cattle becoming bogged in identical sediments today. It is possible that A. wintonensis was killed by D. matildae while attempting to prey on the bogged sauropod or by other theropods fighting over the carcass. Although it is possible that A. wintonensis could have also become bogged in the muddy sediments, the metabolic energy of a carnivorous animal makes this scenario unlikely. The discovery of numerous sauropod dinosaur carcasses in the Winton Formation that are preserved in identical fine clay deposits to D. matildae final resting place tend to support the theory that these giants became trapped in drying waterholes, either as a result of dry seasons or frailty associated with old age. It is unlikely that the exact cause of A. wintonensis death will ever be known.
Fossil remains of theropods (carnivorous dinosaurs) number only a few in Australia, with all discoveries being represented by only one or two bone fragments. The fossils from this ferocious carnosaur were discovered in the deposits of a 95-million-year-old billabong by the Australian Age of Dinosaurs Museum and nicknamed, Banjo. A. wintonensis skeleton represents the most complete theropod skeleton yet found in Australia, with approximately 25% of bones recovered and prepared from the meat-eating dinosaur. The A. wintonensis skeleton housed at the Australian Age of Dinosaurs Museum has been designated as the holotype specimen for a completely new genus and species of theropod dinosaur in Australia, named A. wintonensis meaning (latin) Winton's southern hunter. A. wintonensis has been classified as an allosauroid theropod, being most closely related to two similar allosaurpods: F. kitadaniensis and N. salerii. F. kitadaniensis was found in Japan and N. salerii from the Isle of Wight; both are found in fossil deposits aged older than A. wintonensis. Studies of Banjo's bones have revealed that A. wintonensis shared many features with primitive allosaurs, whilst also possessing features found in a more advanced theorpod group called the Caracharodontosaurids.
FOR MORE INFORMATION WE RECOMMEND READING...
Scientific papers, Australovenator wintonensis (Banjo).
Wikipedia, Australovenator wintonensis.
Western Australian Museum, Australovenator wintonensis.