A fossil of a plesiosaur from Angola contains the remains of three other plesiosaurs in its stomach, revealing the cannibalistic behavior of this prehistoric marine predator.
Reconstructed appearance of the prehistoric plesiosaur. Photo: NRP
The plesiosaur, an extinct marine reptile that dominated the Earth’s oceans during the late Cretaceous period, has captivated scientists since its discovery in 1766 near Maastricht, Netherlands. This fearsome lizard is a well-known symbol of microevolution, illustrating the emergence of an entirely new group of animals. Michael Polcyn, a paleontologist at Utrecht University, conducted the most comprehensive study on their early evolutionary process, ecology, and hunting behavior. With the aid of advanced imaging technology, his findings provide new insights into the origin, relationships, and behavior of these giant ancient reptiles, as reported by Interesting Engineering on December 13.
Plesiosaurs first appeared in marine environments around 100 million years ago, resembling the ancestors of modern whales. Over their history of more than 34 million years, they evolved into agile marine predators, filling diverse ecological niches. Despite once dominating the oceans, they went extinct 66 million years ago during a mass extinction event caused by a meteorite impact.
Polcyn’s research focuses on the lesser-known early evolutionary history of plesiosaurs. Utilizing micro-CT scan technology, Polcyn re-examined historical specimens and newly discovered fossils. The results revealed many important anatomical details that help resolve debates about the ancestry and phylogenetic relationships of plesiosaurs. Polcyn’s research confirms that plesiosaurs are more closely related to monitor lizards than to snakes, as previously suggested.
The research process also uncovered details about plesiosaur feeding behavior. Among the most notable discoveries is a fossil from Angola. This specimen contains the remains of three other plesiosaurs in its stomach, one of which belongs to the same species as the predatory specimen. However, Polcyn has not yet concluded whether plesiosaurs were scavengers or actively hunted their prey.
In a broader analysis, Polcyn studied feeding patterns and the spatial separation of hunting areas throughout the evolutionary history of plesiosaurs. By integrating data from specimens worldwide dating back 66 to 92 million years, he demonstrated that they partitioned resources and adjusted their hunting strategies over time. Polcyn’s study serves as an effective example of combining traditional paleontological methods with advanced technology.
