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 Spur, a long filled-in cave network and active quarry in southern Oklahoma, a group of paleontologists say they’ve identified and described the oldest fossilized reptile skin ever found. The soft tissue fossil is a rare find–enabled through a series of chance events. It offers a glimpse into a distant evolutionary past that pre-dates both mammals and the oldest dinosaurs.
The skin sample, about the size of a fingernail and literally paper thin, is described in a study published on January 10 in the journal Current Biology, along with other fossil findings. The ancient, reptilian skin flake is an estimated 286-289 million years old. That’s at least 21 million years older than the next oldest example and more than 130 million years older than the vast majority of comparable samples, which come from mummified dinosaurs that lived in the late Jurassic, says lead study author Ethan Mooney, a biology master’s student at the University of Toronto studying paleontology.
The fossils’ estimated age is based on the site where they were found. Once, Richards Spur was an open limestone cave, but between 286 and 289 million years ago, it filled in with clay and mud deposits, according to Mooney and Maho. During that in-filling process, the cave stopped forming, so the youngest stalagmite rings present in the cave represent the approximate age of the sediments and the fossils they contain, according to previous research using Uranium-Lead radioisotope dating.
Roger Benson, a paleontologist and curator at the American Museum of Natural History who was not involved in the study, agrees these methods and assumptions are sound. “All the evidence, especially what sorts of fossil groups are present, is consistent with an early Permian age (around 300 to 273…
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