Australovenator

AustralovenatorAustralovenator wintonensis
Pronounced	OSS-trah-LOW-ven-ah-tore
Year Named	2009
Diet	Carnivore (Meat-Eater)
Name Means	"Southern hunter"
Time	Middle Cretaceous - 90 MYA
Location	Australia
Taxon	Theropoda, Coelurosauria

Australovenator is an extinct genus of derived theropod dinosaur from the from the Late Albian of the Cretaceous of Australia. belonging to the Megaraptora. It was described in the online journal PLoS ONE in 2009. It is known from partial cranial and postcranial remains.

The species is named in 2009 by the Australian palaeontologist and museum curator Scott Hocknull. The generic name means "southern hunter" in Latin, a reference to where Australia and the fact that it is a theropod. The specific epithet refers to the fossil formation it was discovered in, the Winton Formation. The species was informally named "Banjo" by Banjo Paterson, author of the Australian folk song Waltzing Matilda.

Description and history

Silhouette with known skeletal elements.

Australovenator is based on AODL 604, a partial skeleton including a left dentary, teeth, partial forelimbs and hindlimbs, a partial right ilium, ribs, and gastralia. Australovenator was described in 2009 by Dr. Scott Hocknull and colleagues. The type species is A. wintonensis, in reference to nearby Winton. A phylogenetic analysis found Australovenator to be an allosauroid carnosaurian, with similarities to Fukuiraptor and carcharodontosaurids. The ankles of Australovenator and Fukuiraptor are similar to the Australian talus bone known as Allosaurus sp.

Although the holotype is fragmentary, it represents the most complete theropod from Austrlia to date. It appears to be similar in morphology to Allosaurus and Fukuiraptor, as well as certain features on the charcharodontosaurid Neovenator. According to a cladistic analysis, Australovenator a relatively derived member of the Allosauroidea.

Classification

Dentary

Remains of the animal include an astralagus from Cape Peterson, Victoria, Australia, and was suggested to indicate that Australia was a type of refugium for animals that had gone extinct in other locations and assigning it to Allosaurus. However, Samuel Welles refuted the evidence, citing it appeared like an ornithomimid, with the original authors defending their claims. Fifteen years later, Daniel Chure examined the fossil, finding it was not Allosaurus, but was an allosauroid. In the description of Fukuiraptor, Yoichi Azuma and Phil Currie noted it bore resemblance to their genus. Sometimes, said specimen is given the museum name of Allosaurus "robustus". Hocknull et al. in PLoS ONE (2009) argue the specimen is of Australovenator and has been variously called A. sp. since.

Paleobiology

Bones of the left hand

Australovenator was a medium-sized allosauroid. According to Dr. Hocknull, it was 2 meters (6.6 ft) tall at the hip and 6 meters (20 ft) long. Because it was a lightweight predator, he coined it as the "cheetah of its time".

AODL 604 was found about 60 kilometers (37 mi) northwest of Winton, near Elderslie Station. It was recovered from the lower part of the Winton Formation, dated to the latest Albian. AODL 604 was found in a clay layer between sandstone layers, interpreted as an oxbow lake deposit. Also found at the site were the type specimen of the sauropod Diamantinasaurus, bivalves, fish, turtles, crocodilians, and plant fossils. The Winton Formation had a faunal assemblage including bivalves, gastropods, insects, the lungfish Metaceratodus, turtles, the crocodilian Isisfordia, pterosaurs, and several types of dinosaurs, such as the sauropods Diamantinasaurus and Wintonotitan, and unnamed ankylosaurians and hypsilophodonts. Plants known from the formation include ferns, ginkgoes, gymnosperms, and angiosperms. Like other carnosaurians, Australovenator would have been a bipedal carnivore.