Paleontologists have examined a 183-million-year-old plesiosaur skeleton with well-preserved skin traces from around the tail and front flipper from the Early Jurassic Posidonia Shale of southern Germany.
Life reconstruction of the Jurassic plesiosaur from the Posidonia Shale of southern Germany. Image credit: Joschua Knüppe.
Plesiosaurs (‘near to lizard’ in Greek) are an iconic group of Mesozoic marine reptiles with a rich evolutionary history.
These creatures roamed the vast seas of the Triassic, Jurassic and Cretaceous periods, between 235 and 66 million years ago.
They had a broad, flat body and short tail, a long neck, and four long propulsive flippers they used to ‘fly’ through the water.
Their teeth were conical, stout, sharp, robust and ideal for stabbing and killing large animals
Plesiosaur fossils have been found on every continent on Earth, with key discoveries made in Australia, Europe and North America.
However, accompanying fossilized soft tissues are exceptionally rare.
“Fossilized soft tissue, such as skin and internal organs, is exceptionally rare,” said Miguel Marx, a Ph.D. student at Lund University.
“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.”
The Jurassic plesiosaur specimen from the Posidonia Shale of southern Germany with comparisons. Image credit: Marx et al., doi: 10.1016/j.cub.2025.01.001.
In their research, Marx and his colleagues analyzed a well-preserved plesiosaur from the world-renowned Early Jurassic Posidonia Shale (Posidonienschiefer Formation) of southern Germany.
“Our results reveal an unusual combination of smooth and scaly skin on different parts of the body,” they said.
“We 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.”
“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,” Marx said.
“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.”
“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,” he added.
“I was shocked when I saw skin cells that had been preserved for 183 million years. It was almost like looking at modern skin.”
The team’s results appear this week in the journal Current Biology.
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Miguel Marx et al. Skin, scales, and cells in a Jurassic plesiosaur. Current Biology, published online February 6, 2025; doi: 10.1016/j.cub.2025.01.001
