US paleontologists have uncovered fossils of three new raptor dinosaurs that roamed what is now eastern Utah about 130 million years ago.
Raptors, or Dromaeosauridae, are a diverse family of predatory dinosaurs with a plethora of species that have been discovered within the last two decades and a few that were known previously.
They are remarkable for the presence of an enlarged, recurved claw on the second toe that may have functioned as a predatory weapon, a weapon for finding its place in the pack’s pecking order, a climbing aid, a digging tool, or a combination of functions. Several species from China are covered in birdlike feathers and closely related to birds; thus dromaeosaurids are important in studies of the origin of avian flight.
Body sizes in the family have a large range from about the size of a mockingbird (four-winged Microraptor) to the largest size of a bear (Utahraptor).
A new study, published today in the journal PLoS-ONE, describes three newly found dromaeosaurids from the Lower Cretaceous of Utah and sheds light on the evolution of the dromaeosaurid tail.
One of the species was named Yurgovuchia doellingi in honor of Helmut Doelling in recognition of his more than 50 years of geological research and geological mapping of Utah for the Utah Geological Survey (UGS). The genus name is derived from the Ute word yurgovuch, meaning “coyote,” a predator of similar size to Y. doellingi that currently inhabits the same region.
A partial vertebral column and a part of the pelvis of Y. doellingi was found in 2005 by UGS paleontologist Don DeBlieux in Doelling’s Bowl Bone Bed, an extensive and important dinosaur site that was first discovered as a result of Doelling providing taped-together color photocopies of his then-unpublished geological maps of the Arches National Park region to an unknown young paleontologist named Jim Kirkland in 1990.
The second species is represented by a part of the pelvis and a possibly-associated arm bone.
The third species, found a few miles to the west at Andrew’s Site, consists of a tail skeleton that is unique among known Cedar Mountain dromaeosaurids. This tail is distinctive in the long extensions of bone off of each vertebrae stiffing the tail as a balancing organ.
Although not providing enough information to permit the species to be properly defined, the fossil proves that there were more advanced dromaeosaurs like Velociraptor and Deinonychus living in the same habitats as the giant but more primitive Utahraptor.