‘Colossal’ New Species of Predatory Dinosaur Dwarfed Tyrannosaurs, Scientists Say
Blake de Pastino Nov 22,2013 3 Comments
An enormous new species of predatory dinosaur has been discovered in the fossil beds of southeastern Utah, paleontologists say, a “colossal” carnivore that was the apex predator of its day — even giving tyrannosaurs a run for their money.
Siats meekerorum
An artist’s rendering depicts Siats meekerorum, (pronounced see-atch), which lived 98 million years ago in what’s now southeastern Utah. (Jorge Gonzales)
Though just a juvenile, the newly found specimen measured some 9 meters long and weighed at least 4 tons at the time of its death 98 million years ago.
Adults of its kind were probably half-again as large, dwarfing the tyrannosaurs of its time, according to scientists.
But despite its familiar, T. rex-like build, this new species — named Siats after a cannibalistic, mischievous monster of Ute legend — was no tyrannosaur.
[See photos of a T. rex fossil recently discovered in Montana.]
Instead, it was a member of the even rarer (and harder to pronounce) carcharodontosaurs, or “shark-toothed lizards” — a family of outsized carnivores represented in North America by only one other species.
But that other species lived 10 million to 20 million years before Siats, making Siats something of a missing link in the order of succession of the Ancient West.
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Siats‘ predecessor and fellow carcharodont, known as Acrocanthosaurus, was the top predator of its time in the Early Cretaceous, about 120 million years ago, paleontologists say.
And while Tyrannosaurus rex bears the mantle of being the largest predatory dinosaur ever found on the continent, it didn’t come on the scene until about 68 million years ago.
The discovery of Siats helps clarify the mysterious transition between those two phases, paleontologists say, bridging the gap from when carcharodontosaurs ruled the land and when tyrannosaurs took their place as the West’s apex hunter.
[See evidence of T. rex's predatory behavior: "T. Rex Tooth Found in Dinosaur’s Tail Proves Tyrannosaurus Was a Predator, Study Says"]
“Carcharodontosaurs reigned for much longer in North America than we expected,” said Dr. Lindsay Zanno, paleontologist at North Carolina State University who co-discovered the new species, in a statement.
Indeed, she noted, it was probably when Siats and its fellow carcharodonts finally disappeared that tyrannosaurs were able to develop from relatively small, pesky predators into the likes of the Tyrant King for which their family is famous.
