'Dinosaurs were well-coordinated swimmers'

Dinosaurs may have found walking on the land quite cumbersome, but the gigantic creatures were capable swimmers, able to paddle long distances, Canadian researchers say.
Researcher Scott Persons from the University of Alberta identified some of the strongest evidence ever which suggests that dinosaurs were well-coordinated swimmers and covered huge distances.
Working together with an international research team, Persons examined unusual claw marks left on a river bottom in China that is known to have been a major travel-way for dinosaurs.
Alongside easily identified fossilised footprints of many Cretaceous era animals including giant long neck dinosaur's, researchers found a series of claw marks that Persons said indicates a coordinated, left-right, left-right progression.

"What we have are scratches left by the tips of a two-legged dinosaur's feet," Persons said in a statement.
"The dinosaur's claw marks show it was swimming along in this river and just its tippy toes were touching bottom," said Persons.

The claw marks cover a distance of 15 meters which the researchers said is evidence of a dinosaur's ability to swim with coordinated leg movements. The tracks were made by carnivorous theropod dinosaur that is estimated to have stood roughly 1 meter at the hip.
Fossilised rippling and evidence of mud cracks indicate that over 100 million years ago the river, in what is now China's Szechuan Province, went through dry and wet cycles.

The river bed, which Persons describes as a "dinosaur super-highway" has yielded plenty of full foot prints of other theropods and gigantic four-legged sauropods.
With just claw scratches on the river bottom to go with, Persons said the exact identity of the paddling dinosaur can't be determined, but he suspects it could have been an early tyrannosaur or a Sinocalliopteryx.
Both species of predators were known to have been in that area of China.
The study was published in the journal Chinese Science Bulletin.