Although you might assume that specimens in a museum's collection have already been "discovered," important new details can still turn up on closer study. That was the case with a plesiosaur skeleton that had been sitting in a German museum for more than 50 years, as a new investigation discovered that not only did the bones belong to a new species, but the animal was the oldest of its kind.

Discovered in a clay pit in Sarstedt, Germany, back in 1964, the bones had been part of a collection at the Lower Saxony State Museum in Hannover for decades. The skeleton included most of the skull, some vertebrae, ribs and bones from the creature's flippers, making it clear that they belonged to some kind of plesiosaur, a group of marine reptiles that lived alongside the dinosaurs.

The museum recently invited scientists to study the specimen, and the team found that it was a new species, that belonged to the elasmosaur family. One of the largest types of plesiosaur, elasmosaurs were also known to have the longest necks of any known vertebrates, containing up to 75 individual neck vertebrae in some species. While not all of this specimen's neck bones were accounted for, it's estimated to have had 40 or 50 vertebrae, making the entire creature some 8 m (26 ft) long.

The researchers dubbed the new species Lagenanectes richterae. The first part of the name translates to "Lagena swimmer," after the medieval name for a river near where the bones were found. The second part is a tribute to the Chief Curator at the museum housing the skeleton, Annette Richter.

In studying the specimen, the team spotted several interesting anatomical features. Channels running through the upper jawbones probably contained nerves, which would have connected to pressure receptors or electroreceptors on the animals' snouts, helping them hunt down prey. Evidence of long-term bacterial infection was also detected in the bones.

"The jaws had some especially unusual features," says Jahn Hornung, co-author on the paper. "Its broad chin was expanded into a massive jutting crest, and its lower teeth stuck out sideways. These probably served to trap small fish and squid that were then swallowed whole."

The other key thing about Lagenanectes was its age. Previously, elasmosaurs were thought to have lived during the Late Cretaceous, between 80 and 65 million years ago. This species however was swimming around a waterlogged ancient Europe some 132 million years ago.

"The most important aspect of this new plesiosaur is that it is amongst the oldest of its kind," says Benjamin Kear, senior author on the study. "It is one of the earliest elasmosaurs, an extremely successful group of globally distributed plesiosaurs that seem to have had their evolutionary origins in the seas that once inundated Western Europe."

The Lagenanectes skull will go on display at the Lower Saxony State Museum, and the research was published in the Journal of Vertebrate Paleontology.

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