Dinosaurs that lost a finger show evolution in action

A TWO-FINGERED dinosaur may help researchers better understand how animals evolve to lose digits. Oviraptorids, a group of bird-like dinosaurs, usually had three fingers on each hand. But a set of juvenile skeletons have two-fingered hands, suggesting an adaptation.

New Scientist, UK: Gregory Funston at the University of Edinburgh, UK, and his team have named the dinosaur, which was probably ostrich-like, Oksoko avarsan. Unlike its three-fingered relatives, the new species had shorter forearms and only two functional, stout fingers with a limited range of motion (Royal Society Open Science, doi.org/fcth).

That means it may have used its hands for nest-building instead of grabbing prey, says Funston. Over millions of generations, animals evolve away body parts that become less useful – including fingers and toes, says Funston. It is akin to the loss of the tail in humans after they evolved to walk upright.

The researchers acquired the skeletons after Mongolian customs officials confiscated them from black market fossil traders. While this was enough to confirm the discovery of a new species, the illegal nature of the excavation has prevented a full investigation of their origins.

(c) 2020 New Scientist Ltd.

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