Toothless Dinosaur’s Lost Finger Points to Spread of Parrot-Like Species

The Oksoko avarsan dinosaurs socialized together as juveniles, perhaps as a form of protection from predators. (Art by Michael Skrepnick / University of Edinburgh)

(CN) — Birds are thought to be the modern-day remnants of dinosaurs, and a recently discovered toothless, two-fingered specimen is illuminating how a group of animals resembling parrots evolved during the late Cretaceous epoch.

Dubbed Oksoko avarsan, this recently discovered dino has one less finger than its nearest relatives, and a complete lack of teeth. The feathered and winged creatures had a large beak resembling that of a parrot but grew to a whopping six feet long — very much unlike a parrot. They were obligate omnivores and are thought to have been opportunistic hunters.

The skeletons were recently discovered in Mongolia’s Gobi Desert by a team from the University of Edinburgh. The fossils discovered by the team were incredibly well preserved and demonstrate the first known evidence of digit loss in the typically three-fingered oviraptor family of dinosaurs. Researchers describe their find in a study published Tuesday in the journal Royal Society Open Science.

Oviraptors are a group of smaller dinosaurs that evolved from theropods, the ancestors of modern-day birds, which represent over 10,500 currently living species. Oviraptor is Latin for “egg seizer” in a gentle nod to the animal’s dietary preference — though some paleontologists now believe that may be misleading as the creature in question was likely brooding over its own nest.

The researchers believe Oksoko avarsan modified its diet and behavior which enabled them to diversify and thrive in times of ecological uncertainty, leading to the loss of a no-longer-necessary third digit. That finger didn’t just disappear overnight, however. It slowly shrank over time as the animals migrated to new locations, specifically the Gobi Desert and North America, which intrigued the team as to what other adaptations may have occurred in similar creatures.

They are thought to have been socially active juveniles, a common trait among many animals from the Cretaceous, as the team discovered four young specimens well-preserved together in a group. 

“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,” said Gregory Funston, a postdoctoral researcher at the University of Edinburgh and lead author of the study, in a statement.

“But more importantly, 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,” he added. “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 study authors did not respond to requests for comment by press time.

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