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Horse size dino sheds light on T. Rex?

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Maybe. From Nature:

The tyrannosaurs of the late Cretaceous period (80 million to 66 million years ago) are among the biggest carnivores to have walked the Earth. But their predecessors — who lived as far back as 170 million years ago, in the Jurassic period — were much smaller; they were generally no bigger than a horse. They also had proportionally smaller heads and longer arms, and lacked the sense of smell and ability to hear low-frequency sound of later tyrannosaurs.

A 20-million-year gap in the fossil record, from 100 million years ago to the time of the giant tyrannosaurs’ appearance, has made it difficult to trace how the keen-sensed giant carnivores evolved. But fossil fragments found in the Kyzylkum desert belong to a newly described horse-sized dinosaur that lived 92 million to 90 million years ago [Timurlengia euotica], slotting neatly into this gap, palaeontologists report. “This is what we’d been waiting for,” says Stephen Brusatte, a palaeontologist at the University of Edinburgh, UK, who led the team that announced the find in the Proceedings of the National Academy of Sciences on 14 March. More.

A paleontologist friend writes to say that he is puzzled by the fact that Nature is calling this an “evolutionary intermediate that slots right in place in terms of both time and its anatomy.” But, looking at the diagram from Nature, they seem to have found only a handful of small fragments of the skeleton, on which they created (invented?) this detailed, sophisticated reconstruction. The “intermediate” is exactly what they wanted it to be.

That’s the trouble when we don’t have enough information. Whether it is the fall of Troy or the death of the dinosaurs, we are tempted to just fill it in.

But there are still lots of bones out there.

See also: Tyrannosaur lunch: Another tyrannosaur

and

Get lost, tyrannopunk! Siats has spotted you!

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