Extremely long necks probably helped ancient marine reptiles ambush prey in murky waters, but also made them easy targets for decapitation by predators
Fossils of two Triassic reptiles show severed heads and necks with bite marks, highlighting a drawback of the extremely long necks common to many ancient sea creatures.
“We provide the first tangible proof that this body plan was, at least in some animals, a weak spot,” says Eudald Mujal at the Stuttgart State Museum of Natural History in Germany.
Tanystropheus, a genus of reptiles that lived in the Triassic Period, had stiff necks up to 2 metres long that may have allowed them to capture fish and other animals with their crocodile-like heads while keeping their bodies less visible on the sea floor.
Mujal and his colleague Stephan Spiekman, also at the Stuttgart museum, used high-resolution photography and 3D modelling to assess the fossils of two species, Tanystropheus hydroides and Tanystropheus longobardicus, on display at the University of Zurich, Switzerland.
The 242-million-year-old specimens included two complete, well-preserved skulls and two equally well-preserved, but abruptly shortened spines
with one animal having only 10 of its 13 neck vertebrae, and the other only seven. Both necks had multiple bite marks, including one that showed the telltale signs of a break caused by a violent impact, the researchers say.
Traces of teeth in both specimens reveal that a predator attacked from behind and above, crushing and completely severing the neck.