Shocking Scientists: Fossilized Plesiosaur Skin Cells Discovered After 183 Million Years

Skeleton of the New Plesiosaur at the Urwelt Museum Hauff in Holzmaden, Germany — Skeleton of the new plesiosaur at the Urwelt-Museum Hauff in Holzmaden, Germany. Credit: Klaus Nilkens/Urwelt-Museum Hauff

Scientists at Lund University analyzed soft tissue from a 183-million-year-old plesiosaur fossil, discovering both smooth and scaly skin.

Researchers at Lund University in Sweden have analyzed the soft tissue of a fossilized plesiosaur for the first time, revealing that the long-necked marine reptile had both smooth and scaly skin. This combination likely helped it swim efficiently while also allowing movement along rough seabeds.

Plesiosaurs inhabited the world’s oceans throughout much of the Mesozoic Era (203–66 million years ago). These reptiles, which could grow up to 12 meters long, fed primarily on fish and propelled themselves using four paddle-like flippers, similar to sea turtles. Until now, little has been known about their external anatomy.

Reconstruction of the New Plesiosaur — Reconstruction of the new plesiosaur with scales on the flipper and smooth scale-less skin along the body as informed by this new plesiosaur fossil. This is a significant update to how we reconstruct plesiosaurs which has otherwise not change substantially since their initial discovery more than 200 years ago. Credit: Joschua Knüppe

However, in a new study published in the scientific journal Current Biology, a research team led by scientists from Lund University has managed to analyze soft tissue from a 183-million-year-old plesiosaur found near Holzmaden, Germany.

“Fossilized soft tissue, such as skin and internal organs, is exceptionally rare. We used a broad range of techniques to identify smooth skin in the tail region as well as scales along the rear edge of the flippers. This provided us with unparalleled insights into the appearance and biology of these long-extinct reptiles,” says Miguel Marx, a PhD student in geology at Lund University and the lead author of the study.

Skin From the Bottom Half of the Tail in the New Plesiosaur — Skin from the bottom half of the tail in the new plesiosaur. The skin as preserved is beige in color with some parts showing a pitted surface. This pitted surface represents the underside of the skin, with the outer surface facing into the rock matrix. Credit: Klaus Nilkens/Urwelt-Museum Hauff

The results reveal an unusual combination of smooth and scaly skin on different parts of the body. The researchers believe this variation could be related to different functions.

The plesiosaur needed to swim efficiently to catch fish and squid-like animals, a task made easier by its smooth and hydrodynamic skin. However, it also needed to move across rough seafloors, which the scaly flippers would have likely allowed it to do.

Miguel Marx Photographing the Skeleton at the Urwelt Museum Hauff in Holzmaden, Germany — Miguel Marx photographing the skeleton at the Urwelt-Museum Hauff in Holzmaden, Germany. Credit: Miguel Marx

Enhancing Our Understanding of Prehistoric Life

“Our findings help us create more accurate life reconstructions of plesiosaurs, something that has been extremely difficult since they were first studied over 200 years ago. Also, the well-preserved German fossil really highlights the potential for soft tissue in providing valuable insights into the biology of these long-extinct animals,” explains Miguel Marx.

By reconstructing the appearance of ancient animals, researchers can enhance our understanding of macroevolution and the adaptations required to survive in specific environments. In recreating the past, we can also better understand Earth’s history and where we are headed.

The Tip of the Right Flipper With Two Scales Along the Trailing Edge — The tip of the right flipper with two scales along the trailing edge. Credit: Klaus Nilkens/Urwelt-Museum Hauff

“Apart from the mosaic of smooth skin and scales, it was an incredible moment to visualize the cells in thin sections of the fossilized plesiosaur’s skin. I was shocked when I saw skin cells that had been preserved for 183 million years. It was almost like looking at modern skin,” says Miguel Marx.

Reference: “Skin, scales, and cells in a ” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>Jurassic plesiosaur” by Miguel Marx, Peter Sjövall, Benjamin P. Kear, Martin Jarenmark, Mats E. Eriksson, Sven Sachs, Klaus Nilkens, Michiel Op De Beeck and Johan Lindgren, 6 February 2025, Current Biology.
DOI: 10.1016/j.cub.2025.01.001

The following institutions and organizations participated in the study: Lund University, Uppsala University, RISE (Research Institutes of Sweden), Naturkunde-Museum Bielefeld, and Urwelt-Museum Hauff.