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Old September 14th, 2013 #13
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Ancient Crocodiles Ran Like Dogs and Hunted like Killer Whales

Ancient relatives of crocodiles were equipped with a diverse set of characteristics that enabled them to compete and survive in a dinosaur-dominated world, according to new research published in the journal Proceedings of the Royal Society B.

Some of the ancient crocodiles were able to amble across the land with the ease of a dog, while others stayed beneath the seas and hunted prey in a fashion similar to killer whales today.

The new research from scientists at University of Bristol, the Royal Veterinary College and Duke University reveals how the jaws of ancient crocodiles were evolved to suit creatures in vastly different environments as they lived along side the dinosaurs from 235 to 65 million years ago.

"The ancestors of today's crocodiles have a fascinating history that is relatively unknown compared to their dinosaur counterparts. They were very different creatures to the ones we are familiar with today, much more diverse and, as this research shows, their ability to adapt was quite remarkable," said research leader Tom Stubbs from the University of Bristol.

"Their evolution and anatomical variation during the Mesozoic Era was exceptional. They evolved lifestyles and feeding ecologies unlike anything seen today."

Curious to see how extinction events and adaptations to extreme Mesozoic environments impacted the feeding systems of ancient crocodiles, the researchers analyzed the shape and biomechanical function of the lower jaws in more than 100 of the creatures spanning a wide range of time in the Mesozoic era.

The fossil records revealed how ancient crocodiles responded to the devastating end-Triassic extinction event, responding by evolving to a changed habitat and food supplies.

"Our results show that the ability to exploit a variety of different food resources and habitats, by evolving many different jaw shapes, was crucial to recovering from the end-Triassic extinction and most likely contributed to the success of Mesozoic crocodiles living in the shadow of the dinosaurs," said Stephanie Pierce, from the Royal Veterinary College.

Ancient Crocodiles Ran Like Dogs and Hunted like Killer Whales : Animals : Nature World News

A sample of jaws from the Mesozoic crocodile fossil record. From top to bottom jaws are from: Kaprosuchus (Cretaceous) (image by Carol Abraczinskas), Simosuchus (Cretaceous), Mariliasuchus (Cretaceous) (courtesy of The American Museum of Natural History), Dakosaurus (Jurassic to Cretaceous) and Cricosaurus (Jurassic to Cretaceous) (courtesy of Jeremías Taborda).