Skin Fossil from 300-Million-Year-Old Reptile is the Oldest Known

The collection of fossilized skin fragments is the oldest ever discovered. This 300 million-year-old fossil belongs to a crocodile-like reptile and could help us understand how skin evolved.

After an animal dies, the skin decomposes quickly, so fossilization is rare. But this early Paleozoic reptile eventually ended up in a suitable place to preserve its skin. It was buried in oily clay deposits in an ancient limestone cave in what is now Oklahoma. There was little oxygen in the cave sediments, which slowed the decomposition process long enough for the tissue to fossilize, trapping the mummified skin mold.

The discovery was a surprise to researchers who had been examining the tiny black fossil fragments using microscopic 3D scans. “They were so small and skinny that we had to be very gentle with them,” he says. tea maho At the University of Toronto, Canada. Their scans revealed a pebble-like scale texture similar to crocodile skin, especially the flatter, smaller scales on the crocodile's flanks.

Researchers concluded that the skin belonged to a Paleozoic reptile, but it is unclear which species. Based on nearby fossils, they suspect the skin belongs to an extinct lizard-like species. Captorinus aguti. It's not clear how the reptile reached its final resting place. Perhaps it fell into the cave from a vertical shaft or was swept into the cave by a heavy rainstorm.

The fossilized skin fragments are about 21 million years older than any previously discovered, showing how and when vertebrates developed skin after they transitioned from living in the sea to living on land. It reveals new clues about how it evolved. “This is a unique opportunity to examine the first chapter in the evolution of higher vertebrates,” he says. ethan mooney at the University of Toronto. Skin helped aquatic animals make the leap to life on land by providing a watertight barrier between sensitive organs and the outside world.