Abdelrahman
A remarkably well-preserved fossil estimated to be 183 million years old has unveiled fascinating details about the appearance of some plesiosaurs. This ancient marine reptile had a unique combination of skin and scales, suited to their predatory lifestyle in ancient seas.
Plesiosaurs, iconic creatures that roamed the oceans alongside dinosaurs, went extinct millions of years ago. While remains have been discovered globally, the rare preservation of soft tissues alongside skeletal structures is a significant find. This particular specimen, uncovered in Germany’s Posidonia Shale and dating back to the Lower Jurassic period, is noteworthy for its completeness. It shows evidence of skin around its tail and front flipper, marking a groundbreaking opportunity for scientists to study plesiosaur soft tissues in detail.
The researchers identified various pigment cells, including melanosomes and keratinocytes, within the tail samples. They discovered three distinct layers of skin cells: the stratum corneum (the outer epidermal layer), stratum spinosum (the middle layer), and stratum basale (the innermost layer).
Additionally, the flippers featured structures similar to those found in modern reptiles, indicating that these ancient creatures had smooth skin on their bodies and tails, while their limbs bore small scales. This revelation is particularly surprising, as other marine reptiles from the Mesozoic era, like ichthyosaurs, did not exhibit scales.
“Finding fossilized soft tissue, such as skin and other internal structures, is extremely rare. We employed various advanced techniques to analyze the smooth skin in the tail area and the scales along the flippers,” explained Miguel Marx, a geology PhD student at Lund University and lead study author. “These insights provide an unprecedented look into the biology and appearance of these long-extinct reptiles.”
This discovery enhances our understanding of what plesiosaurs looked like, a challenge that has persisted since they were first studied over 200 years ago. The well-preserved fossil serves as a key resource, revealing valuable biological details about these formidable marine predators.
The combination of skin types likely reflected adaptations that improved their swimming efficiency and ability to navigate rough coastal terrains—smooth skin aiding in hydrodynamics and scaly flippers offering protection. Thus, these prehistoric giants were adept hunters in various ocean depths.
Such extraordinary finds provide researchers with critical insights into the evolutionary history of life on Earth, revealing that while certain aspects of organisms, such as skin, have remained surprisingly consistent, other features have evolved profoundly over millions of years.
“This blend of smooth skin and scales was astonishing. Observing skin cells preserved for 183 million years felt like witnessing modern skin,” Marx added.
The full study is published in Current Biology.
