Cave in Oklahoma Holds Oldest Preserved Skin Sample
In a breakthrough discovery, paleontologists have identified a minuscule fragment of ancient skin found in a cave in Oklahoma as the oldest known piece of preserved skin. The findings, published in the journal Current Biology, provide valuable insights into the adaptations of early terrestrial animals and may offer clues about the development of feathers and hair.
The fossilized skin, which measures no larger than a human fingernail, dates back approximately 289 million years to the early Permian period. During this time, Earth’s continents were connected to form a supercontinent, and a diverse range of ancient plants, reptiles, amphibians, and insects flourished.
The warm and arid climate of the Permian played a critical role in facilitating the transition of early reptiles from semi-aquatic to fully land-based lifestyles. These reptiles eventually gave rise to the evolution and divergence of mammals and reptiles. However, the Permian period ended with a devastating mass extinction event that wiped out around 90% of the planet’s species.
Studying fossils from the Permian period allows scientists to gain valuable insights into the ancestral animals that ultimately evolved into the diverse life forms we see today.
Although the exact species to which the fossilized skin belongs remains unknown, its microscopic structures indicate that it belonged to a group called amniotes, which encompasses mammals, reptiles, and birds. The skin’s patterning closely resembles that of crocodile skin, suggesting that early reptiles and their relatives may have possessed similar skin characteristics.
“This fossil find demonstrates the first major innovation in the structure of the largest organ of the body, which is the skin,” said Robert Reisz, a paleontologist from the University of Toronto at Mississauga and a co-author of the study.
The skin fossil was discovered by an amateur collector while exploring the Richards Spur limestone cave system, a renowned fossil site in Oklahoma. The collector donated the fossil to researchers in 2018, who then conducted a thorough examination. The delicate nature of the skin required it to be embedded in epoxy and cut with a fine-tipped diamond saw for microscopic analysis.
The exceptional preservation of the skin is attributed to the conditions within the clay-rich cave, including the presence of oil seepage. Hydrocarbons found in oil seeps can prevent decomposition and degradation by sealing off soft tissues from oxygen and microbial activity.
From their analysis, the researchers were able to determine that the fossil is anatomically similar to the extinct species Captorhinus aguti, which thrived during the Permian period. It is believed that this species had flexible and tough bands of skin or epidermal tissue that served protective, movement, or structural purposes.
The significance of this discovery lies in its contribution to understanding the transition from the common ancestor of mammals and reptiles, which occurred during the Paleozoic Era encompassing the Permian period. According to Paul E. Olsen, a paleontologist and professor at Columbia University, the finding prompts further investigation into the types of skin reptiles possessed during that time.
The Permian period’s discoveries offer crucial insights into Earth’s evolutionary history, ancient ecosystems, and environmental changes during this pivotal era. Ultimately, these findings shed light on the ancestors of the diverse animal groups that exist today.