The illustration shows S. sullivani attacking a hadrosaur. (Credit: Mary P. Williams)

dinosaurs

Little dinosaur had a killer sense of smell

A newly discovered dinosaur that was closely related to Velociraptor, the group of creatures made infamous by the movie Jurassic Park, was a fierce predator—thanks in large part to its sharp sense of smell.

Researchers discovered the 75 million-year-old fossil specimen—part of the dinosaur’s skull—in the Bisti/De-Na-Zin Wilderness Area of New Mexico in 1999. When first described, scientists believed it was a member of Saurornitholestes langstoni, a species of theropod dinosaurs in the Dromaeosauridae family that had been found in present-day Alberta, Canada.

But a comparative analysis of the specimen, dubbed Saurornitholestes sullivani, to other S. langstoni specimens showed subtle differences. Notably, the surface of the skull corresponding with the brain’s olfactory bulb was unusually large, implying a powerful sense of smell.

Intimidating predator

“This feature means that Saurornitholestes sullivani had a relatively better sense of smell than other dromaeosaurid dinosaurs, including Velociraptor, Dromaeosaurus, and Bambiraptor,” says Steven Jasinski, a doctoral student in the earth and environmental science department at the University of Pennsylvania. “This keen olfaction may have made S. sullivani an intimidating predator as well.”

The new species comes from the end of the time of dinosaurs, or the Late Cretaceous, and represents the only named dromaeosaur from this period in North America south of Montana.

At the time lived, North America was split into two continents separated by an inland sea. It lived on the western shores in an area called Laramidia.

Numerous dromaeosaurs, which are commonly called raptors, are known from more northern areas in Laramidia, including Alberta and Montana. However, S. sullivani represents the only named dromaeosaur from the Late Cretaceous of southern Laramidia.

Dinosaur neighbors

S. sullivani shared its world with numerous other dinosaurs. Plant-eating contemporary dinosaurs included the duck-billed hadrosaurs Parasaurolophus tubicen 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.

Though a distinct species, S. sullivani appears to be closely related to S. langstoni. Finding the two as distinct species further shows that differences existed between dinosaurs between the northern and southern parts of North America.

At less than 3 feet at its hip and roughly 6 feet in length, S. sullivani was not a large dinosaur. However, previous findings of related species suggest the animal would have been agile and fast, perhaps hunting in packs and using its acute sense of smell to track down prey, Jasinksi says.

“Although it was not large, this was not a dinosaur you would want to mess with.”

The Jurassic Foundation provided funding for the work. Jasinski reported his findings this month in the New Mexico Museum of Natural History and Science Bulletin.

Source: University of Pennsylvania

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