A newly discovered species of toothless, two-fingered dinosaur has shed light on how a group of parrot-like animals thrived more than 68 million years ago.
The unusual species had one less finger on each forearm than its close relatives, suggesting an adaptability which enabled the animals to spread during the Late Cretaceous Period, researchers say.
Multiple complete skeletons of the new species were unearthed in the Gobi Desert in Mongolia by a University of Edinburgh-led team.
Named Oksoko avarsan, the feathered, omnivorous creatures grew to around two metres long and had only two functional digits on each forearm. The animals had a large, toothless beak similar to the type seen in species of parrot today.
The remarkably well-preserved fossils provided the first evidence of digit loss in the three-fingered family of dinosaurs known as oviraptors.
The discovery that they could evolve forelimb adaptations suggests the group could alter their diets and lifestyles, and enabled them to diversify and multiply, the team says.
Researchers studied the reduction in size, and eventual loss, of a third finger across the oviraptors’ evolutionary history. The group’s arms and hands changed drastically in tandem with migrations to new geographic areas — specifically to what is now North America and the Gobi Desert.
The team also discovered that Oksoko avarsan — like many other prehistoric species — were social as juveniles. The fossil remains of four young dinosaurs were preserved resting together.