Jasinski, a doctoral candidate in the Department of Earth and Environmental Science and curator of paleontology and geology at the State Museum of Pennsylvania, was reviewing the museum's collection when he found a fossil that caught his eye. “As soon as I looked at the specimen, I could tell it was not the dinosaur it was thought to have been,” he told Live Science.
The fossil was originally believed to be Saurornitholestes langstoni, a species within the Dromaeosauridae family. Dromaeosaurs are colloquially referred to as raptors, due to the popularization of a specific genus of dromaeosaur: Velociraptor.
The specimen is a skull fragment with an unusually large structure in the forebrain, known as the olfactory bulb. This suggests the dinosaur had a sharp sense of smell, Jasinski said.
The dinosaur's acute nose likely helped it to be a competitive predator, potentially by allowing it to hunt at night, the researchers said. This keen sense of smell could have also aided in communication — namely, by helping the dinosaur detect chemical signatures called pheromones in other dinosaurs, which is crucial for animals that live and hunt in packs.
Jasinski compared the fossil to other dromaeosaurs using holotype specimens, which essentially act as the dictionary definition of a species. Holotype specimens are agreed upon by scientists to be the most representative examples of an animal. Jasinski compared the skull fragment to available samples in the western United States, Canada, Mongolia, China, and Europe, but his fossil remained unique. This gave him reasonable grounds to declare that he had found something entirely new: Saurornitholestes sullivani.
S. sullivaniwas relatively small compared to other species alive during the late Cretaceous, but its speed, agility, and impressive olfactory capability gave it a necessary advantage over other predators. It could have brought down a meal and eaten quickly before a tyrannosaur could come by and capitalize on the food. It was thriving about 8 million to 10 million years before the dinosaurs died out, when a good mix of herbivores and carnivores were coexisting. At the time, a large seaway divided North America into two major continents: Laramidia to the left of the seaway and Appalachia to the right. S. sullivani lived on the eastern portion of Laramidia.
Most large herbivores, like duck-billed dinosaurs, would have been too large for a small dromaeosaur to take down, so packs of S. sullivani would target juveniles or subadults.
Nick Longrich, a senior lecturer at the University of Bath, whose research focuses on the end-Cretaceous mass extinction that wiped out the dinosaurs, has discovered new dinosaur species in the same manner as Jasinski. Rummaging through forgotten museum collections is a far cry from the romanticized, Indiana Jones-esque paleontological fantasy, he said.
“I’ve done fieldwork and love the badlands but it’s expensive and it’s too much of a lottery," Longrich told Live Science. "Everyone assumes it’s a great way to do science but National Geographic does not cover all the failed field expeditions."
One of the main challenges is that there are gaps in our knowledge of the many species that once roamed the Earth. “The fossil record is incomplete enough that if you’re in a new area or a new time, there’s a fair chance that the dinosaurs there are going to be distinct," Jasinski said. For instance, scientists might discover a toe from a brand new species, but such subtle differences may be unrecognizable or impossible to prove.
"hings that we call separate species today would be very, very hard to tell apart based on their skeleton (crow versus raven, for example),” Longrich told Live Science in an email. He went so far as to suggest that because S. sullivani is so noticeably distinct to the naked eye, Jasinski may have identified an entirely new genus, rather than just a new species.
Read more at Discovery News
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