Utahraptor
Utahraptor was a giant dromaeosaur, related to Deinonychus and Velociraptor. Like it’s relatives, it had a large curved claw on each foot, and likely had feathers.
Classification: Saurischia. Theropoda. Dromaeosauridae.
Genus: Utahraptor (“Thief of Utah”)
Species: U. ostrommaysi
Utahraptor was a meat-eating predator, like its relatives. However, while other dromaeosaurs were primarily known for their speed, Utahraptor was not particularly fast due to its size and stocky body. Scientists believe it was likely an ambush predator, not unlike an alligator or crocodile, that would use stealth to get close to its prey before taking it by surprise.
It probably ate iguanodonts and other plant-eating dinosaurs, using its claws and jaws to subdue its prey. There is some evidence that Utahraptor may have hunted in packs, though investigations into fossils are still ongoing and there is no scientific consensus on this matter yet.
Utahraptor had many features typical of dromaeosaurs, including a mouth full of sharp teeth, a large sickle-shaped claw on each foot, a long stiff tail, and very likely a body covered in feathers.
However, it was much larger and heavier than most other dromaeosaurs. Utahraptor was originally thought to be able to reach sizes of over 20 feet, though recent estimates put it closer to 16 or 18 feet at the longest. Still, this is far bigger than relatives like Microraptor (which was only about two and a half feet long), Velociraptor (which grew to around six feet long) and Deinonychus (which could reach up to 11 feet in length).
Utahraptor was also thicker and stockier than most dromaeosaurs, which tended to be agile and slender. The claws on its hands were also more suited to cutting than those of its relatives. Rather than a thin, narrow head like that of Velociraptor, Utahraptor’s head was deep and almost square-shaped with a blunt snout.
Dromaeosaurs are known for the oversized claws present on the second toe of each foot. In the case of Utahraptor, these claws could be over nine inches long!
LENGTH: Up to 5.5 meters (18 feet)
WEIGHT: 300 kg (660 pounds)
Utahraptor, as its name implies, lived in what is now Utah in the Early Cretaceous Period, around 130 million years ago. It was an apex predator of the area, and may even have preyed upon dinosaurs larger than itself, like long-necked sauropods.
Its environment was a semi-dry habitat with floodplains, forests, and open wooded areas. It lived alongside numerous other dinosaurs including the ankylosaur Gastonia, the sauropods Cedarosaurus and Moabosaurus, and iguanodonts Hippodraco and Cedrorestes.
The first remains of Utahraptor were discovered in 1975 but did not receive much attention. Utahraptor gained notoriety when further remains were uncovered in the early 1990s, coincidentally around the release of the blockbuster film Jurassic Park. The movie featured Velociraptors that were much larger than the actual dinosaurs, and the discovery of huge raptor fossils around the same time received much media attention. The species was originally going to be named Utahraptor spielbergi, after Steven Spielberg, the director of Jurassic Park, but paleontologists ultimately decided on U. ostrommaysi, which refers to paleontologist John Ostrom, whose influential research helped link dinosaurs like Deinonychus to birds.
More Utahraptor remains were discovered in 2001. These fossils appear to show up to seven Utahraptors, as well as a plant-eating dinosaur that would have served as their prey. It is believed this plant-eater may have become stuck in quicksand, and as the Utahraptors came to eat the helpless dinosaur, they became stuck as well. This may show evidence of pack-hunting behavior, though it is also possible that the Utahraptors were drawn to the stuck dinosaur individually.
These fossils helped provide a much clearer picture of what Utahraptor looked like, and they are still being examined today.
References
https://en.wikipedia.org/wiki/Utahraptor
Paul, G. (2016). The Princeton Field Guide to Dinosaurs, 2ndEdition. Princeton, New Jersey: University Press Princeton.
Safari Ltd Utahraptor Toys