Usually, fossilized animal remains result from bits of bone or impressions of a creature long-passed. But sometimes a specific place has just the right conditions to preserve even more. From Richards ...

A dark shred of fossilized material, just a few millimetres across, “shocked” palaeontologists when they realized what it was. It arrived in a tiny glass vial, sent by fossil collectors in Oklahoma.

Almost 300 million years ago, a small reptile walked through a limestone cave system in what is now Oklahoma. Today, a fragment of its skin, no bigger than a fingernail and as thin as a human hair, is ...