This latest finding sends tyrannosaurs back
to the Northern Hemisphere.
Image: iStockphoto
In a study published online today in Science, the team
argues that a pair of pelvic bones discovered at Dinosaur Cove, southern
Victoria, over 20 years ago, does not belong to a tyrannosaur.
“Our examination of these bones shows that the key features
considered by the original research team to link them to tyrannosaurs
are not present,” said PhD candidate Matt
Herne from the UQ School of
Biological Sciences, who led the research.
“Other features of the bones are also found in more distantly
related theropod dinosaurs, some of which are already known from the
southern continents,” Mr Herne said.
While it often possible to broadly determine which group of
dinosaurs a single bone might belong to, more complete and ideally
associated skeletal remains are usually required to accurately identify
something down to a specific family.
“This is clearly the case with the Victorian pelvic bones, which
were identified as belonging to a tyrannosaur using a very low level of
anatomical support,” Mr Herne said.
The British and Australian research team who described the bones in
April, considered them to belong to a close relative of Tyrannosauridae,
the group of theropods that includes well-known dinosaurs such as
Tyrannosaurus rex.
This family of large, hyper-carnivorous theropods is otherwise known
only from the Late Cretaceous of the Northern Hemisphere.
“While we do not discount the possibility that tyrannosaurs may have
been present on the southern continents, these particular bones do not
provide the conclusive evidence that the original research team claims,”
Mr Herne said.
“We think it is far more likely that these pubic bones belong to a
type of theropod that is already known from Australia or one of the
other southern continents.
"They may also belong to a new group that we have not seen before.
“We simply need more of this animal in order to be sure.”
The occurrence of tyrannosaurs in Australia is also not consistent
with the current understanding of dinosaur biogeography.
“During the time that most of Australia's dinosaurs are known to
have existed, there is strong evidence for animals moving between many
of the landmasses that once comprised the southern supercontinent of
Gondwana — of which Australia was a part,” said Dr
Steve Salisbury, who was part of the team from UQ.
“There is now growing fossil
evidence that Australia's dinosaur faunas were similar to those
that occurred on the other Gondwanan continents.
"Tyrannosaurs do not appear to have been a part of this southern
dinosaur fauna,” Dr Salisbury said.
“Despite 100 years of collecting, no tyrannosaur remains have been
found in any of the southern continents.
"It looks like things will stay that way, at least for the time
being.”
Editor's Note:
Original news release can be found here.
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