Newly discovered fossils of a toothless, parrot-like dinosaur species that lived more than 68 million years ago reveal a creature with two fingers on each forearm. That's one less digit than its close dino relatives had.
The fossils imply that the dinosaurs may have evolved forelimb adaptations that enabled them to spread during the Late Cretaceous Period, researchers say in a new study published Wednesday in The Royal Society Open Science journal. Paleontologists from the University of Edinburgh found a number of complete skeletons of the new species during a dig in Mongolia's Gobi Desert.
The feathered, omnivorous Oksoko avarsan grew to around 6.5 feet (2 meters) long. In addition to two functional digits on each forearm, the dinosaurs appeared to have large, toothless beaks, much like modern-day parrots.
"Its two-fingered hand prompted us to look at the way the hand and forelimb changed throughout the evolution of oviraptors -- which hadn't been studied before," University of Edinburgh professor and study co-author Gregory Funston said in a statement. "This revealed some unexpected trends that are a key piece in the puzzle of why oviraptors were so diverse before the extinction that killed the dinosaurs."
The dinosaurs' arms and hands changed dramatically during slow migrations to new geographic areas in the Gobi Desert and North America.
The newly discovered fossils of four young Oksoko avarsan dinosaurs show them resting together, which the scientists think may be further proof the dinosaurs were social as juveniles.
"Oksoko avarsan is interesting because the skeletons are very complete and the way they were preserved resting together shows that juveniles roamed together in groups," Funston said.
Researchers from the University of Alberta and Philip J. Currie Dinosaur Museum in Canada, Hokkaido University in Japan, and the Mongolian Academy of Sciences also contributed to the study.