forelimb

But "even though the forelimbs have already been eaten, the head is remarkably well preserved", he added.

The carcass—containing the head, forelimbs, and front part of the animal—was discovered encased in a chunk of ice in 2020 near the Badyarikha River in northern Siberia, above the Arctic Circle.

ATVs, dune buggies and other off-road vehicles can slam into the slow-moving tortoises with domed shells and heavily scaled, flattened forelimbs used for digging.

The loss of flight — which plays out at the phenotype level in changes in the forelimb, for example — thus resulted from way more than a single change in the genome.

"I think what drew me to the specimen wasn't its lack of teeth -- it was its forelimbs," says O'Connor.