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Bizarre New Horned Tyrannosaur From Asia

Bizarre New Horned Tyrannosaur From Asia

Just a few weeks after tiny, early Raptorex kriegsteini was unveiled, a new wrench has been thrown into the family tree of the tyrannosaurs.

The new Alioramus altai - a horned, long-snouted, gracile cousin of Tyrannosaurus rex - shared the same environment with larger, predatory relatives.

A paper published this week in the Proceedings of the National Academy of Sciences describes this exceptionally well-preserved fossil, shedding light on a previously poorly understood genus of tyrannosaurs and describing a new suite of adaptations for meat eating.

“This spectacular fossil tells us that there is a lot more anatomical and ecological variety in tyrannosaurs than we previously thought,” says Stephen Brusatte, a graduate student affiliated with the American Museum of Natural History. “Not all tyrannosaurs were megapredators adapted for stalking and dismembering large prey. Some tyrannosaurs were small and slender. Compared to Tyrannosaurus, this new animal is like a ballerina.”

Mark Norell, Chair of the Division of Paleontology at the Museum, agrees. “We now have evidence of two very different tyrannosaurs that lived in Asia at the same time and place — just like today, where lions and cheetahs live in the same area but look dissimilar and exploit their environment differently.”

Tyrannosaurs are bipedal predators that lived at the end of the Cretaceous (from 85 million years to approximately 65 million years ago) is currently known from several groups of fossils. One subfamily from North America includes Albertosaurus and Gorgosaurus, while the other subfamily bridges Asia and North America and includes Tyranosaurus, Tarbosaurus, and Alioramus.

Both T. rex and Tarbosaurus are remarkably similar, even though they lived on different continents; both were predators with massive jaws and thick teeth that could crunch through bones. In fact, bite marks have been found on somefossils that were prey.

Until now, Alioramus was known only from fragmentary fossils that were briefly described decades ago by a Russian paleontologist, and it has long been debated whether Alioramus was a proper tyrannosaur, a more primitive cousin, or perhaps a juvenile Tarbosaurus.

Alioramus altai

"Top: Skeletal reconstruction of Alioramus altai. Below: New tyrannosaur Alioramus altai in a scientifically reconstructed scene. (Credit: Skeleton: Frank Ipolitto / Scene: Jason Brougham)"

Source: American Museum of Natural History

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