While many have long hoped that the Loch Ness Monster is today's plesiosaur, skeptics point out that plesiosaurs lived in the ocean. However, a new study now suggests that some of these creatures may live in freshwater channels.
Plesiosaurs were a group of prehistoric aquatic reptiles characterized by long necks , small heads , and four paddle-shaped fins. They existed for about 150 million years and went extinct at the same time as the dinosaurs 66 million years ago (although there are some theories by Loch Ness Monster enthusiasts).
In a recent study — conducted by the Universities of Bath and Portsmouth in the UNITED Kingdom and hassan II University in Morocco — scientists reported on plesiosaur fossils found in a 100-million-year-old river system in what is now the Sahara Desert in Morocco. More specifically, the fossils were excavated from a sediment called kem kem's bed.
The remains belong to a relatively small plesiosaur because they include bones and teeth from the 3 m long (9.8 ft) adult plesiosaur, and forelimb bones from the 1.5 m (4.9 ft) juvenile plesiosaur. Estimates of body size are based on previously discovered complete skeletons of the same family, known as Leptocleididae.
Dr Nick Longrich, corresponding author of the study and university of Bath, said: "These bones and teeth were scattered in different places, not as a skeleton. So every bone and every tooth is a different animal. We have more than a dozen animals in this series. ”
These teeth exhibited similar wear and tear to those seen on fossil teeth of the semi-aquatic dinosaur Spinosaurus, which lived in the same river as Plesiosaurus. This is an important discovery because it suggests that plesiosaurs fed on fish in the same way as dinosaurs.
If they do, it means they may have been in the river for a long time — or even living there for a long time — rather than occasionally swimming from the sea for quick access. In addition, due to the relatively large number of teeth found, it is conceivable that plesiosaurs stayed in the river long enough to lose and regrow teeth.
Finally, it should be noted that the remains of Leptocleididae have previously been found in saltwater or freshwater fossil beds, although this batch of latest fossils is unprecedented. That said, the existence of pure freshwater plesiosaurs of the past is still far from certain.
"People ask, how can paleontologists have any definitive understanding of the lives of animals that went extinct millions of years ago? The reality is, we can't always be like this," Longrich said. "All we can do is make educated guesses based on the information we have." We will find more fossils. Maybe they'll confirm those speculations. Probably not. ”
The paper on the study was recently published in the journal Cretaceous Studies.