Massive, meat-eating predatory dinosaur unearthed

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Researchers from Chicago’s Field Museum, the North Carolina Museum of Natural Sciences and North Carolina State University announced Friday the discovery of Siats meekerorum, a dinosaur that stretched more than 30 feet long, in eastern Utah.

Given its size and other characteristics, they believe this creature ruled its ecosystem in the middle of the Cretaceous, a period known as the last in the so-called “Age of Dinosaurs.”

It’s not known if Siats meekerorum existed alongside Tyrannosaurus rex; fossils found from the same patch of Utah’s Cedar Mountain Formation shows it did share the land with tyrannosaurs. But relatively speaking, these tyrannosaurs were much smaller (and below the 7 or so tons of later T. Rexes) and definitely down on the predatory food chain.

“At least 98 million years ago, we know that (tyrannosaurs) were small and somebody else was top dog in the neighborhood,” said Peter Makovicky, The Field Museum’s dinosaur curator.

“(Siats meekerorum) is a large dinosaur,” he adds. “And we have no evidence — nor do the teams that worked in this area prior to us — of anything bigger.”

Its size and appearance alone are reason enough to excite paleontologists. But there are a few other facts that make this find noteworthy, said Makovicky.

One is that Siats meekerorum helps to fill in a roughly 30-million-year gap in the geologic record in North America, a period for which relatively little is known about dinosaurs on the continent. Another: Its closest carchardontosaurian (the family it hails from) kin hailed from elsewhere in the world, suggesting there was more movement and dispersion of dinosaurs at a time the continents had largely already drifted apart than had been thought.

“Until 10 years ago, we thought this was a time period when North American dinosaurs were isolated,” Makovicky said. “The evidence is growing that was not actually the case. Dinosaurs were quite good at spreading around the world.”

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