Feathered dinosaur was among last surviving raptors, paleontologists say

PHILADELPHIA — It is well known that modern birds are related to the dinosaurs that roamed the earth millions of years ago. Birds are the only feathered animals we know of, but it’s believed feathers are a trait they received from their prehistoric ancestors. A recent fossil discovery of a new type of feathered dinosaur seems to indicate that more dinosaurs were feathered than we previously thought.

The dinosaur fossils were originally discovered in the San Juan Basin of New Mexico by Robert Sullivan of the New Mexico Museum of Natural History and Science in Albuquerque. The full specimen was discovered over four field seasons by a team that Sullivan led along with Steven Jasinski, a curator of paleontology and geology at the State Museum of Pennsylvania.

New feathered raptor
A new feathered dinosaur that lived in New Mexico 67 million years ago is one of the last known surviving raptor species, according to a new publication in the journal Scientific Reports. Dineobellator notohesperus adds to scientists’ understanding of the paleo-biodiversity of the American Southwest, offering a clearer picture of what life was like in this region near the end of the reign of the dinosaurs. (Image credit: Sergey Krasovskiy)

The research team named the dinosaur Dineobellator Notohesperus, which means “Navajo warrior from the Southwest” to honor the Navajo people who still reside in the region where this dinosaur once roamed the earth. Dineobellator is a member of the dromaeosaurid family, a group of predatory dinosaurs that’s more commonly known as “raptors” like in the “Jurassic Park” movie series.

Dineobellator lived about 67 million years ago, right before an asteroid struck the earth and wiped out all dinosaurs. Some features of the fossils provide clues to what this dinosaur looked like and how it lived.

The raptors in the “Jurassic Park” movies are depicted as enormous, terrifying beasts. Dineobellator is actually not quite as large as Hollywood would have you think — only 3.5 feet tall at the hip and about 6-7 feet in length.

These dinosaurs had relatively larger and longer forearms than other dinosaurs that lived at the time like the Tyrannosaurus Rex. Dineobellator also had larger claws that provided it with extraordinary strength and grasping abilities. These features helped make it one of the more ferocious predators because it could prey on both smaller animals and other large dinosaurs.

The Dineobellator also had a unique tail that was optimal for predation. Most dinosaurs have tails that are stiff throughout. The tail of the Dineobellator was pretty flexible at its base while the rest of the tail would stay stiff.

New feathered raptor
Another reconstruction depicts
Dineobellator notohesperus
with nestlings. (Image credit: Mary P. Williams)

Jasinski comments on the utility of a tail like this in a release: “Think of what happens with a cat’s tail as it is running. While the tail itself remains straight, it is also whipping around constantly as the animal is changing direction. A stiff tail that is highly mobile at its base allows for increased agility and changes in direction, and potentially aided Dineobellator in pursuing prey, especially in more open habitats.”

What the researchers found most interesting about the fossil of the Dineobellator is the presence of quill knobs in the bones of their forearms. These knobs are small bumps on the surface of the bone that show where feathers were anchored by ligaments. “As we find evidence of more members possessing feathers, we believe it is likely that all the dromaeosaurids had feathers,” says Jasinski.

This fossil discovery really informs our understanding of the dinosaurs that inhabited this area of New Mexico and their relatives. Jasinski plans to continue searching for fossils in this area. “It was with a lot of searching and a bit of luck that this dinosaur was found weathering out of a small hillside,” he says. “We do so much hiking and it is easy to overlook something or simply walk on the wrong side of a hill and miss something. We hope that the more we search, the better chance we have of finding more of Dineobellator or the other dinosaurs it lived alongside.”

The discovery is published in Nature: Scientific Reports.