New Long-Necked Marine Reptile Discovered In Germany

Germany’s Posidonia Shale is famous for its exceptionally well-preserved marine fossils that date back to the Early Jurassic. Scientists have studied this treasure-trove for nearly 500 years. Recently, paleontologists have identified a new species of marine reptile from this site.

The new species has been described in PeerJ and named Plesionectes longicollum. The name Plesionectes comes from the Greek plēsíon (meaning “near” or “close”) and nēktēs (“swimmer”), while longicollum derives from Latin for “long neck.”. 

The animal itself belongs to a group called the plesiosaurs. These are long-necked marine reptiles that swam Earth’s oceans during the dinosaur age (and famously served as the inspiration for the loch ness monster). 

A Fossil Hidden for Decades

The nearly complete skeleton was originally dug up in 1978 from a quarry in Holzmaden, southwest Germany. Despite being in a museum collection for many years, its unique anatomy wasn’t fully recognized until now. 

“This specimen has been in collections for decades, but previous studies never fully explored its distinctive anatomy,” says Sven Sachs, lead author and researcher at Naturkunde-Museum Bielefeld. This species is now recognized as the earliest plesiosaur discovered in the Holzmaden region.

What Makes Plesionectes longicollum Special?

This reptile stands out. It has an unusually long neck, containing at least 43 vertebrae, and a high number of vertebrae (~21) in its back. This is more than most known similar plesiosaurs. About half of its 3 meter body is its neck. These features distinguish it from other known Jurassic plesiosaurs. Even though the described specimen was not fully grown at its death, its anatomical traits were clearly distinct enough to classify it as a brand-new genus and species. 

The fossil even reveals traces of soft tissue around the neck, tail, and rear limbs, rare details that give insight beyond just bones. Unfortunately, the skull is largely missing, having been crushed in the fossilization process. 

A Glimpse into Ancient Ocean Life

Plesionectes longicollum is the earliest known plesiosaur from the Holzmaden region, dating back to about 183 million years ago, in the early Toarcian stage of the Jurassic. The Toarcian was marked by a major oceanic anoxic event, and marine oxygen levels dropped globally, drastically affecting ocean ecosystems. This discovery could help scientists understand how marine life responded to these stressful conditions.

The Europe that this plesiosaur inhabited was not one landmass like the Europe we know today. It was a group of tropical islands separated by shallow seas. “The discovery adds another piece to the puzzle of marine ecosystem evolution during a critical time in Earth’s history,” says Daniel Madzia, co-author and paleobiologist at the Polish Academy of Sciences.