Illustration by Matt von Rooijen
Published March 19, 2010
Like a zombie clawing its way out of the grave, a new dinosaur species was discovered when scientists spotted a hand bone protruding from a cliff in the Gobi desert of Inner Mongolia, paleontologists have announced.
"We were looking at these very tall red sandstone walls that were all abraded by the wind, and I saw this claw sticking out of the side of the cliff," recalls Jonah Choiniere, a grad student at George Washington University in Washington D.C. who found the fossil on a dig in 2008.
The claw wasn't protruding much: Less than a fingertip's worth of the bone was exposed. But further investigation revealed "bone after bone," Choiniere said, until the team had unearthed a nearly complete skeleton—one of the most complete raptor fossils ever found.
It was fortunate the team found the fossil when they did, Choiniere added, because once exposed, the dinosaur would have been rapidly lost to the elements.
"Erosion is very quick there," Choiniere said. "The whole specimen could have been turned to powdered bone dust in a few years, easily."
New Dinosaur Had Killer Claw
Stretching about 8 feet (2.5 meters) and weighing 55 pounds (25 kilograms), Linheraptor would have been a fast, agile animal that preyed on small horned dinosaurs related to Triceratops, which also lived the area. (See other prehistoric creatures of the Cretaceous.)
It's unclear how this particular Linheraptor died, but one idea is that it suffocated beneath a sand avalanche.
Sand dunes in the region are notoriously unstable, Choiniere said, and an earthquake, a storm, or the minute shifting of sand grains could have been enough to trigger a collapse.
"It's great for paleontologists, but it must have been terrible to be trapped in it," said Choiniere, whose study of the fossil appears online today in the journal Zootaxa.
Finding such a well-preserved new raptor is important, because it helps reveal the evolution of raptors from smaller, birdlike dinosaurs, said Tom Holtz, a paleontologist at the University of Maryland who was not involved in the study. (Take a dinosaur quiz.)
For instance, like its more famous relative the Velociraptor, Linheraptor possessed a large "killing claw" on each foot, which it may have used to bring down prey. (Related: "Jurassic Park Raptors Had Feathers, Fossil Suggests.")
This claw "is fairly big in Linheraptor, but it's not as big as in Velociraptor and Deinoychus," another famous raptor, Holtz noted. The claw that Choiniere initially spotted, however, was not Linheraptor's killing claw, but another claw on the dinosaur's hand.
Linheraptor also stands out from its raptor relatives because it has an unusually large lobe in a sinus cavity called the antorbital fenestra, a unique feature that will require further study to explain.
"It's not a missing link," Holtz added of Linheraptor. "But it does represent a grade of raptor between the earliest forms, such as those we know from early Cretaceous China, and the classic late forms, such as Velociraptor."
The find is also remarkable, he said, since "the team gave it the species name exquisitus, and it certainly fits that, because it's a wonderful specimen."
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