A newly discovered species of mosasaur called Gavialimimus almaghribensis ruled the inland seas 66 million years ago. A three-foot-long skull and other bones were discovered in a phosphate mine in Morocco where over a dozen other types of mosasaurs have already been found.
“Morocco is an incredibly good place to find fossils, especially in these phosphate mines,” noted Catherine Strong who is a graduate researcher at the University of Alberta in Canada. “Those phosphates themselves reflect sediments that would have been deposited in marine environments, so there are a lot of mosasaurs there.”
Mosasaurs (meaning “Lizard of the Meuse River”) were marine predators that could also breathe in air. They lived during the Late Cretaceous Period between 72 million and 66 million years ago. While some mosasaurs were as small as three feet in length, the majority of them grew over 10 feet long with some as large as 50 feet. They were very sleek with smooth scales that were dark in color. They had flipper-like paddles and a tail fin. Even though they had two sets of teeth in their upper jaw, they were able to open their mouth wide enough to swallow their prey whole.
The Gavialimimus almaghribensis had a unique crocodile-like snout which would have helped it to catch fast-swimming fish. “Its long snout reflects that this mosasaur was likely adapted to a specific form of predation, or niche partitioning, within this larger ecosystem,” Strong explained.
It’s quite interesting how numerous mega-predators could all live and thrive in the same inland seas. Each of the mosasaurs would have evolved to feast on certain prey different from the other species in order for them to all survive with none of them being desperate for food.
One example is the Globidens simplex that had fat round teeth that would have helped them to break through shells to reach their food. “Not all of the adaptations in these dozen or so species are this dramatic, and in some cases there may have been some overlap in prey items,” Strong stated, adding, “But overall there is evidence that there's been diversification of these species into different niches.”
She went on to say, “This does help give another dimension to that diversity and shows how all of these animals living at the same time in the same place were able to branch off and take their own paths through evolution to be able to coexist like that.” A picture of the skull as well as an artist’s impression of the Gavialimimus almaghribensis can be seen here.
Their study was published in the Journal of Systematic Paleontology and can be read in full here.