Debate Over Identity of Australian Tyrant Dinosaur
Discovery and Description
In March 2010, a team of paleontologists led by Roger Benson announced the discovery of a partial hip bone of a tyrannosauroid dinosaur from Australia. This discovery marked the first evidence of this group of dinosaurs on the southern continent.
The hip bone, known as the pubis, is a distinctive feature of tyrannosaurs, particularly the last ones to evolve. The Australian specimen exhibited several characteristics that suggested it belonged to a tyrannosaur, including a robust shape and a downward-oriented front portion.
Controversy
However, in a recent comment published in the journal Science, Matthew Herne, Jay Nair, and Steven Salisbury argued that the evidence for a tyrannosaur from Australia is not as strong as Benson proposed.
Herne and his colleagues pointed out that the anatomical details initially used to diagnose the bones as tyrannosaur are also seen among other theropods, a group of carnivorous dinosaurs that includes tyrannosaurs. They proposed that the Australian bones could have come from one of the many other theropod dinosaur varieties already known from Australia, such as coelurosaurs or carcharodontosaurians.
Response
Benson and the other authors of the original paper disagreed with Herne’s interpretation. In a reply published alongside the comment, they maintained that a peculiar feature of the hip bone, known as the pubic tubercle, is most similar to the same feature in tyrannosaurs.
Even though the pubic tubercle is broken, Benson and his colleagues argued that the orientation of the missing portion can still be determined. They believe that if the bone were complete, it would show a condition similar to that of tyrannosauroid dinosaurs.
Geographic Implications
The discovery of a possible tyrannosaur in Australia has implications for our understanding of dinosaur diversity and geographic distribution.
For decades, paleontologists believed that dinosaurs could be divided into two main groups: northern (Laurasian) and southern (Gondwanan). However, recent discoveries have shown that this division is not as simple as once thought.
The closest relative of the Australian theropod Australoventaor, for example, is Fukuiraptor from Japan. This discovery suggests that some groups of dinosaurs were able to cross what were once thought to be geographic barriers.
Ongoing Debate
The debate over the identity of the Australian tyrannosaur is ongoing. Two groups of researchers have looked at the same fossils and come to very different conclusions. More fossils will be needed to know for sure whether the bones belong to a tyrannosaur or another type of theropod.
Additional Research
Paleontologists are eagerly awaiting the announcement of further remains from this contested Australian dinosaur. Additional fossils could provide more definitive evidence and help to resolve the debate over its identity.
In the meantime, the discovery of a possible tyrannosaur in Australia has sparked excitement and debate among paleontologists. It is a reminder that our understanding of dinosaur diversity and distribution is constantly evolving as new discoveries are made.
