Plesionectes longicollum: Germany’s “Very Strange” Jurᴀssic Sea Monster – The Perfect Mix of Neck and Teeth!

Paleontologists have finally named Plesionectes longicollum (“long-necked near-swimmer”)—a bizarre new Early Jurᴀssic plesiosauroid whose 47-year-old fossil reveals one of the strangest marine reptiles ever found.

Excavated in 1978 from a quarry in Holzmaden, southwestern Germany, the nearly complete skeleton lay unrecognized in the collections of the Staatliches Museum für Naturkunde Stuttgart until a comprehensive 2025 study. The specimen, from the world-famous Posidonia Shale (~183 million years ago), preserves an exceptionally elongated neck, a small skull, and even traces of fossilized soft tissue—making it the oldest known plesiosaur from the Holzmaden area.

Described by Sven Sachs and colleagues in PeerJ (August 2025), Plesionectes stands out for its extreme neck length relative to body size and a unique denтιтion combining piercing and grasping teeth. These features suggest a specialized feeding strategy: sweeping its hyper-elongated neck through schools of fish or squid while its teeth acted like a precision trap. The animal likely inhabited shallow epicontinental seas that covered much of Europe during the Toarcian stage.

“This fossil sat in a drawer for nearly five decades before its true significance was revealed,” noted lead author Sven Sachs. “It adds a crucial piece to the puzzle of early plesiosaur evolution and shows how even well-studied fossil sites can still yield surprises.”

From the black shales of Holzmaden, Plesionectes longicollum emerges as a 183-million-year-old masterpiece of neck engineering—a strange and wonderful sea monster that redefines what we thought possible for Jurᴀssic marine reptiles.