Tyrannosaurs didn’t used to be so scary. For millions of years, they were kind of puny, never bigger than a horse. They probably lurked in the underbrush while larger dinosaurs like Allosaurus ruled the land as the top predators.
Jump forward to the end of the Cretaceous Era, and we see the astonishing creature we call Tyrannosaurus rex, a schoolbus-sized monster with a giant head, teeth as big as bananas and powerful jaws that could bite through bone.
How the small tyrannosaurs turned into these menacing giants has long been a mystery because of a vast gap in the fossil record. But on Monday, scientists gathered at the Smithsonian National Museum of Natural History in Washington to reveal a newly discovered dinosaur that appears to be the long-sought missing link.
Fossils of the new dinosaur, dubbed Timurlengia eutoica, were found in the central Asian nation of Uzbekistan. The species appears to have been about the size of a horse and without the absurdly huge head and the industrial-strength jaws of T. rex.
But its brain case indicates that it was rather intelligent, like T. rex, and had many of that dinosaur’s advanced sensory abilities, including the ability to hear low-frequency sounds. The discovery strongly suggests that tyrannosaurs got smart before they got very large.
“The skill set was the key qualification to apply for the job of top predator,” said Hans-Dieter Sues, a paleontologist at the Smithsonian and a co-author of a paper describing the discovery, which was published Monday in the Proceedings of the National Academy of Sciences. “Our new beast certainly had very good hearing, certainly better than any other tyrannosaur.”
Tyrannosaurs had been around since the Jurassic Period, but given their modest stature, they were far from being dominant. Their evolution into apex predators is hard to track because of the patchiness of the fossil record in the Cretaceous Period.
There are very few places on Earth where fossils of terrestrial animals from about 80 to 100 million years ago can be found. Where sediments from that era exist, they typically are marine sediments, which are useless for studying land-dwelling dinosaurs.
But the remote site in Uzbekistan, 17 miles from the nearest road, is a rare exception. Sues did field work there for 10 summers starting in 1997, driving around in beat-up Soviet-era military vehicles, buying mutton from desert nomads and keeping spirits up with plenty of vodka. The site produced a trove of fossils that were later analyzed in museums and laboratories around the world.
Timurlengia — named for the 14th century conqueror Tamurlane — lived about 90 million years ago. The scientists describe it as a forerunner, or remote cousin, of T. rex rather than a direct ancestor. The fossil hunters did not find a full skeleton. Rather, they just have scraps of Timurlengia — remnants of many animals scattered in the bone beds.
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SOURCE: The Washington Post, Joel Achenbach