The fossilized two-fingered hands found in a collection of dinosaurs has revealed a new species, according to a new study led by a University of Alberta alumnus.
The study focuses on a block of three bird-like dinosaurs preserved together, said Greg Funston, lead author of the study in a news release Thursday. The specimens belong to a group of oviraptorids, a subgroup of a larger group called oviraptorosaurs.
“Initially, we suspected that these fossils might be already known, but after comparing them to the possibilities, it became clear that there were significant differences that told us we were looking at a new species,” said Funston, who completed part of the research during his doctoral studies in the department of biological sciences at the University of Alberta.
“The two-fingered hand was a completely unexpected twist. As I was initially working on the specimen, I noticed that most of the knuckle bones of the third finger were missing in the fossil.”
At first, Funston didn’t find it that unusual to have the knuckle bones missing, as fossils are often found damaged or incomplete. But when the other hand was revealed, it indicated something new.
“To my surprise, even though the bones were completely surrounded by rock and the finger should have been preserved, the third finger still only had one bone,” Funston said.
“Looking more closely at this bone, we could tell that it didn’t form a joint, and so we could be confident that this species only had two fingers in life. This is unusual because other species in the group all have three fingers, and no one had ever suspected that these animals were losing their digits over time.”
The same phenomenon has also been seen in other dinosaurs, like the tyrannosaurs.
The study names this new species Oksoko avarsan. It also describes the morphology of the skeleton and explores biological information the fossils provide about the dinosaurs.
“This pattern shows that these animals were highly adaptable, and we suspect that this is related to their dietary flexibility,” Funston said.
The find has also prompted scientists to look more closely at the evolution of hands and forelimbs, providing more insight on evolutionary trends as subgroups of the oviraptorosaur group migrated to different areas.
“The pattern of diversification and adaptation that we see fits into an ongoing puzzle of whether dinosaurs were already in decline before their extinction 66 million years ago,” Funston said.
“A lot of new work has shown that this is probably not true. Our work shows that this group was flourishing in Asia just before the extinction, and so the pattern we thought we saw in North America is probably not representative of the whole world.”
Copyright Postmedia Network Inc., 2020
