Evolution: fossil skin 290 milllion years old (Evolution)

by David Turell , Thursday, January 11, 2024, 17:57 (107 days ago) @ David Turell

Reptile like:

https://www.sciencealert.com/this-tiny-texture-on-rock-is-the-earliest-known-fossil-of-...

"It's just a tiny thing, smaller than a fingernail. But a rock found deep in a limestone cave in Oklahoma is extending our understanding of prehistoric skin.

"The texture preserved thereon, paleontologists have found, is the earliest known example of fossilized skin from a diverse classification of animals known as amniotes.

'Dating back 290 million years ago – a full 21 million years earlier than the previous record-holder – its wearer appears to have been a reptile, with a pebbly surface similar to the skins of crocodilians today.

"Given how important skin is, acting as a protective barrier that keeps outside contaminants out and our blood and guts in, the discovery is an important one for piecing together its evolutionary history, scientists say.

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"The newly discovered skin fossil, however, is something really special. The skin has been carbonized in 3D, the first record we have of this from the Paleozoic. It's also the earliest known preserved skin fossil that includes, not just the outer layer, but what are almost certainly structures associated with the deeper dermis layer.

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"Unfortunately, we don't know more about the animal to whom the skin once belonged; no associated skeleton was found. However, the non-overlapping pebbled surface resembles the skin of modern crocodilians, and the hinged regions between the scales resemble the skins of animals such as snakes and worm lizards.

"The discovery, the researchers say, shows that, even very early on, when amniotes first started to diverge, skin was present and important.

"'In particular," they write in their paper, "the presence of an epidermis with hinges and scale-like protuberances underscores the importance of this component of the amniote skin as a barrier against the harsh terrestrial environment."

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"The skin also offers us a new tool for interpreting the subsequent development and emergence of mammalian hair follicles and avian feathers. The first mammals appear on the fossil record about 225 million years ago, and birds around 150 million years ago. So this mystery animal could be a clue about the development of our own soft fleshy skins.

"There's a lot we still don't know about how the various traits of different animal groups diverged and developed. Finding early examples of this trait is a rare and special window into the history of all this planet's strange and wonderful forms of life."

Comment: that we need a protective skin in obvious. That it looks just like a crocodile skin tells us its creation produced a perfect skin type lasting all those useful years.