New Australian dinosaur fossil shows that tyrannosaurs's range was global

[Ichingcarpenter]

Tyrannosaur bones are relatively familiar finds on the northern continents of the globe, cropping up everywhere from modern-day Colorado to China. But until now, they appeared to be oddly missing from the southern half of the globe. The discovery of a distinctively tyrannosaur-like hipbone in Victoria, Australia, however, might change the way scientists think about the distribution—and evolution—of this infamous group of dinosaurs.

"The absence of tyrannosauroids from the southern continents was becoming more and more anomalous as representatives of other 'northern' dinosaur groups started to show up in the south," Paul Barrett, of the Department of Paleontology at the Natural History Museum in London and a coauthor of the new report, said in a prepared statement.

The hipbone fossil is 30 centimeters long. "The bone is unambiguously identifiable as a tyrannosaur because these dinosaurs have very distinctive hip bones," asserted lead study author Roger Benson, of the Department of Earth Sciences at the University of Cambridge, in a prepared statement.


"The new discovery shows that this is wrong and that 110 million years ago tyrannosaurs were probably global. This poses a question. Why did tyrannosaurs grow to giant size and dominance in the north, but apparently not in the south?"

Dr Rich says the new species of Tyrannosaurus also shows the likelihood of finding a unique Australian dinosaur is low.

"The picture that seems to be emerging is that dinosaurs were more or less cosmopolitan," he says.

http://www.scientificamerican.com/blog/post.cfm?id=new-australian-dinosaur-fossil-show-2010-03-25

Did they find it in a billabong where maybe a dingo ate its baby?

[dipsydoodle]

1. Given that they probably couldn't swim

and its doubtful they were into boat building this implies they survived the plate shift which left Oz as an island.

[muriel_volestrangler]

2. It claims this was from when all the southern continents were still connected

This as-yet unnamed dinosaur lived about 110 million years ago—about 40 million years before its revered relative the T. rex. At this time, the southern continents (Australia, Africa, South America and Antarctica) were still connected to each other, providing the researchers with "hints at the possibilities that others remain to be discovered in Africa, South America and India," Barrett said.

though other sources claim there was significant breakup before then:

The breakup of Gondwana occurred in stages. Some 180 million years ago, in the Jurassic Period, the western half of Gondwana (Africa and South America) separated from the eastern half (Madagascar, India, Australia, and Antarctica). The South Atlantic Ocean opened about 140 million years ago as Africa separated from South America. At about the same time, India, which was still attached to Madagascar, separated from Antarctica and Australia, opening the central Indian Ocean.

http://www.britannica.com/EBchecked/topic/238402/Gondwana

I'm not sure who to believe. Even when I go to the Natural History Museum, it's not entirely clear:

http://www.nhm.ac.uk/hosted_sites/paleonet/MacLeod/pdfs/cretaceous.pdf (can't copy from this)

It says the rift between Africa and India started about 140 million years ago, and continued until they had split apart by 150 million years ago. :shrug: It fairly clearly states that India, Australia and Antarctica were still connected 110 Ma, but the rifts separating India from the other 2 were beginning to form then.

[dipsydoodle]

3. I thought Gondwana

was a heavy metal group.

Can't India's movement be verified by the age of creation of the Himalayas ?

[muriel_volestrangler]

4. The Himalayas can tell us when it crashed into Asia

but not, I'd think, when it separated from other continents a long time before that. I presume they look at sea floor spreading and things like that, but it may be very complicated.