Paleontologist Steven Jasinski of the University of Pennsylvania has described a new species of dromaeosaurid dinosaur that roamed what is now New Mexico during the Upper Cretaceous epoch, approximately 75 million years ago.
Two individuals of Saurornitholestes sullivani attack a subadult hadrosaur Parasaurolophus tubicen. Image credit: Mary P. Williams.
Jasinski named the new species Saurornitholestes sullivani – after paleontologist Robert Sullivan who originally found the dinosaur’s partial skull in the Bisti/De-Na-Zin Wilderness Area of New Mexico in 1999.
When first described, paleontologists believed it was a member of Saurornitholestes langstoni, a species of theropod dinosaurs in the Dromaeosauridae family.
But when Jasinski began a comparative analysis of the specimen to other S. langstoni specimens, he found subtle differences. Notably, he observed that the surface of the skull corresponding with the brain’s olfactory bulb was unusually large.
“This feature means that Saurornitholestes sullivani had a relatively better sense of smell than other dromaeosaurid dinosaurs, including Velociraptor, Dromaeosaurus, and Bambiraptor. This keen olfaction may have made Saurornitholestes sullivani an intimidating predator as well,” Jasinski said.
Saurornitholestes sullivani was a relatively small dinosaur, less than 90 cm (3 feet) tall and 1.80 m (6 feet) in length. However, it would have been agile and fast, perhaps hunting in packs and using its acute sense of smell to track down prey.
75 million years ago, North America was split into two continents separated by an inland sea. Saurornitholestes sullivani lived on the western shores in an area called Laramidia with numerous other dinosaurs.
Plant-eating contemporary dinosaurs included the duck-billed hadrosaurs Parasaurolophus walkeri and Kritosaurus navajovius, the horned dinosaur Pentaceratops sternbergii, the pachycephalsaurs Stegoceras novomexicanum and Sphaerotholus goodwini and the ankylosaurs Nodocephalosaurus kirtlandensis and recently named Ziapelta sanjuanensis.
Other contemporary meat-eating theropods included the tyrannosaurs Bistahieversor sealeyi and Daspletosaurus, along with ostrich-like ornithomimids.
Saurornitholestes sullivani is described in the New Mexico Museum of Natural History and Science Bulletin.
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Steven Jasinski. Saurornitholestes sullivani sp.nov. New Mexico Museum of Natural History and Science Bulletin, May 2015
