This is the oldest skin ever found. The fossil is almost 300 million years old

Amazing stuff!

"... Now, a team of researchers has identified a fragment of fossilized reptile skin that is more than 20 million years older than previously described skin fossils from any animal. The fragment ... dates back to the late Paleozoic Era, when many species began to emerge from the water to live on land. ..."

From the highlights and abstract:

"Highlights

• Oldest-known amniote epidermis as 3D skin cast and several skin compression fossils

• Articulated corneous epidermal bands in basal eureptile Captorhinus aguti

• Hydrocarbons and cave conditions as preservational mechanisms at Richards Spur

• Early Permian anamniote tetrapod dermal scales and likely palpebral ossifications

Summary

The richest and most diverse assemblage of early terrestrial tetrapods is preserved within the infilled cave system of Richards Spur, Oklahoma (289–286 Mya1). Some of the oldest-known terrestrial amniotes are exquisitely preserved here because of early impregnation and encasement of organic material by oil-seep hydrocarbons within rapidly deposited clay-rich cave sediments under toxic anoxic conditions. This phenomenon has also afforded the preservation of exceedingly rare integumentary soft tissues, reported here, providing critical first evidence into the anatomical changes marking the transition from the aquatic and semiaquatic lifestyles of anamniotes to the fully terrestrial lifestyles of early amniotes. This is the first record of a skin-cast fossil (3D carbonization of the skin proper) from the Paleozoic Era and the earliest known occurrence of epidermal integumentary structures. We also report on several compression fossils (carbonized skin impressions), all demonstrating similar external morphologies to extant crocodiles. A variety of previously unknown ossifications, as well as what are likely palpebral ossifications of the deeper dermis layer of the skin, are also documented. These fossils also serve as invaluable references for paleontological reconstructions. Chromatographic analysis of extractable hydrocarbons from bone and cave samples indicates that the source rock is the Devonian age Woodford Shale. Hydrocarbons derived from ancient marine organisms interacting with geologically younger terrestrial vertebrates have therefore resulted in the oldest-known preservation of amniote skin proper."

This is the oldest skin ever found | Science | AAAS Nearly 300-million-year-old fossilized reptile skin found in Oklahoma cave resembles that of modern crocodiles

Paleozoic cave system preserves oldest-known evidence of amniote skin (open access)

Conditions within the limestone caves of Richards Spur in Oklahoma preserved fingernail-size fragments of fossilized reptile skin.

Figure 2Three-dimensional skin cast and compression fossils from unknown amniotes