In a remarkable discovery, researchers have unearthed a three-dimensional fragment of fossilized skin that is approximately 286 million years old, exceeding the age of any known skin fossils by at least 21 million years.
This old skinwhich once adorned early Paleozoic reptiles, has a distinctive pebbled texture, bearing a striking resemblance to modern-day crocodile skin.
This discovery represents the oldest known example of cuticle preservation in terrestrial reptiles, birds, and mammals. It highlights the evolutionary importance of the outer skin layer in adaptation to life on land.
The fossilized skin, along with other specimens, was excavated from the Richards Spur limestone cave system in Oklahoma, a site famous for its unique preservation conditions.
Ethan Mooney, a graduate student in paleontology at U.S University of Toronto The first author of the study expressed his happiness.
“Every now and then we get an extraordinary opportunity to glimpse deep time,” Mooney said. “These types of discoveries could enrich our understanding and awareness of these pioneering animals.”
Fossilized skin is rare
The rarity of soft tissue ossification makes this discovery particularly important. Researchers believe that a combination of soft clay sediments, oil seeps, and an oxygen-poor cave environment Richards Spear It plays a pivotal role in maintaining the skin.
“The animals likely fell into this cave system during the Early Permian and were buried in very fine clay deposits that delayed the decomposition process,” Mooney explains.
“But what is interesting is that this cave system was also the site of an active oil seep during the Permian, and it is likely that it was the interactions between the hydrocarbons in the oil and the tar that allowed this skin to be preserved.”
Small size, big science
Despite its tiny size – smaller than a fingernail – the fossilized skin revealed detailed skin tissue under microscopic examination by co-author T. Maho of University of Toronto Mississauga.
These tissues are a feature of the amniotes, a group of terrestrial vertebrates that includes reptiles, birds and mammals, evolving from amphibian ancestors during the Carboniferous.
“We were completely shocked by what we saw because it was so different from anything we expected,” Mooney says.
“Finding such an ancient skin fossil represents an extraordinary opportunity to look into the past and see what the skin of some of these early animals might have looked like.”
A prehistoric time capsule in this fossilized skin
Features of the fossilized skin included a pebbled surface resembling crocodile skin, and hinge zones between scales reminiscent of snakes and worm lizards.
These distinctive features indicate similarity with ancient and present-day reptiles. However, the absence of associated skeletal remains leaves the exact type or body region of the skin unknown.
This similarity underscores the evolutionary importance of these cutaneous structures for survival in terrestrial environments.
“Edermis was a crucial feature for the survival of vertebrates on land,” Mooney says. “It is a critical barrier between the body's internal processes and the harsh external environment.”
The team hypothesizes that this skin may represent the ancestral structure of terrestrial vertebrates in early amniotes, paving the way for the evolution of bird feathers and mammalian hair follicles.
Richards Spur Cave System
Bill and Julie May, lifelong paleontology enthusiasts, collected the skin fossil and other specimens at Richards Spur.
The unique conditions in this limestone cave system in Oklahoma have preserved many of the oldest examples of early terrestrial animals.
These samples are now in Royal Ontario Museumproviding invaluable insights into the ancient world and its inhabitants.
In short, this discovery of fossilized skin provides a profound glimpse into the ancient world of terrestrial vertebrates.
Through passionate endeavor and careful study, scientists and paleontology enthusiasts alike contribute invaluable knowledge to our collective understanding of the rich tapestry of life that has inhabited our planet over millions of years.
The full study was published in the journal Current biology.
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