One day in 2008, a lethal weapon from a bygone era spilled out of a hillside in New Mexico.

“We knew that it was something interesting right away,” said Steven Jasinski, a paleontologist at the State Museum of Pennsylvania, whose colleague, Robert Sullivan, first spotted the fossil.

The relic turned out to be the claw of a dromaeosaurid, a dinosaur popularly known as a raptor after its starring role in “Jurassic Park.” After more than a decade of field work and research, Dr. Jasinski and his colleagues have now confirmed that the claw — along with 20 other fossils — represents a new species that lived some 68 to 70 million years ago, just a few million years before an asteroid doomed most dinosaurs.

They named the animal Dineobellator notohesperus, describing it Thursday in Scientific Reports. This pint-size predator is the third known North American dromaeosaurid from the dinosaurs’ twilight period, and suggests that beasts of its stature may have been abundant at that time.

“The new animal Dineobellator confirms that there is a greater diversity of raptors at the end of the Cretaceous than has been suspected up until now,” said Philip Currie, a paleontologist at the University of Alberta in Canada, who was not involved with the study. “It represents our steady progress in understanding that small dinosaurs may have been more common than large forms like the contemporary T. rex at the end of the age of dinosaurs.”