Saturday, April 11, 2015

Utah's Dinosaur 'Death Trap' Reveals Trove of Predators

A nine-ton block of sandstone that was pulled from a Utah mountain late last year holds the biggest fossil trove ever found of the giant predatory dinosaur known as Utahraptor. Covered in feathers, with a huge sickle claw on each second toe, Utahraptor looked like a pumped-up version of the Jurassic Park star Velociraptor.
All the Utahraptor fossils are contained within a large blob of sandstone that appears to have once been what geologists call a "dewatering feature," or in common terms, "quicksand".
The Utahraptor was the largest of a group of lightly-built carnivores, called the dromaeosaurs ('swift lizards'). It had large eyes, long grasping hands and powerfully clawed feet. Clearly it was carnivorous, but was distinctive in relying on a wickedly hooked, slashing claw on each foot rather than the jaws and teeth of a typical predator. Its toe joints were specially enlarged so that its massive claw could be raised upward and backward to avoid damage while running.
The dromaeosaur group also included Velociraptor, made famous by Steven Spielberg in 'Jurassic Park'.
By chipping off smaller pieces of the block, Kirkland and his team uncovered bones from a 16-foot-long adult Utahraptor, four juveniles, and a baby that would have been only about three feet long from snout to tail.
Other bones at the site belong to a beaked, bipedal herbivore called an iguanodont. The remains of these dinosaurs may have been what attracted the Utahraptor group to the site in the first place.