new mosasaur species discovered in Morocco | Paleontology

Paleontologists have described a new species of mosasaur based on two complete skulls and jaws found in Morocco.

An artist’s impression of Pluridens serpentis. Image credit: Andrey Atuchin.

Mosasaurs (family Mosasauridae) were specialized marine lizards that evolved and diversified during the Late Cretaceous period.

Their diversity peaked in the Maastrichtian of the Cretaceous, between 72 and 66 million years ago, with the most diverse faunas known from Morocco.

While most of its parents were small, barely a few meters long, the new Moroccan species grew large, perhaps 8 meters long.

Appointed Pluridens serpentis, the sea creature had long, slender jaws with many small hooked snake-like teeth for catching small prey like fish and squid.

Compared to related mosasaur species, it had smaller eyes, suggesting poor vision.

But its muzzle had dozens of nerve openings, hinting at the ability to hunt by sensing water movement and pressure changes. These nerves may have been sensitive to tiny changes in water pressure, an adaptation seen in sea snakes.

“Usually when animals have small eyes it’s because they rely more on other senses,” said Dr Nick Longrich, a paleontologist at the Milner Center for Evolution at the University of Bath.

“The fact that Pluridens serpentis had so many nerves in his face may mean he was using the changes in water pressure to detect animals in low light conditions, whether at night or in deep, dark water.

“If he wasn’t using the eyes, then it’s very likely he was using the tongue to hunt, like a snake.” Many snakes and aquatic lizards – sea snakes, ribbonsnakes, water monitors – wave their forked tongues underwater, using chemical signals to track their prey. “

The well-preserved skull of Pluridens serpentis.  Image credit: Longrich et al., Doi: 10.1016 / j.cretres.2021.104882.

The well-preserved skull of Pluridens serpentis. Image credit: Longrich et al., doi: 10.1016 / j.cretres.2021.104882.

The discovery of Pluridens serpentis brings to 13 the number of mosasaurs known from the last Cretaceous period of Morocco.

“The diversity of these fossils is simply astonishing. Far from declining in diversity, mosasaurs seem to reach their peak just before their extinction, ”said Dr Longrich.

“We see no evidence that this group struggled before it died out. From an evolutionary standpoint, they’ve been successful, they’ve done everything right, but nothing can prepare you for an asteroid.

“It is a new species of large predator which, with its 8 meters long, confirms the diversity of marine fauna just before the Cretaceous crisis”, declared Dr Nour-Eddine Jalil, paleontologist at the History Museum natural. of Sorbonne University.

Pluridens serpentis emphasizes the importance of Morocco’s paleontological heritage to help illustrate the history of life.

“The latest discoveries show perfectly that the list of species present here is far from being closed and that the future still holds great surprises and discoveries”, declared Dr Nathalie Bardet, paleontologist at the National Museum of Natural History in Paris .

A paper describing the discovery was published in the journal Cretaceous research.

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Nicolas R. Longrich et al. Pluridens serpentis, a new mosasaurid (Mosasauridae: Halisaurinae) from the Maastrichtian of Morocco and implications for mosasaur diversity. Cretaceous research, published online 8 May 2021; doi: 10.1016 / j.cretres.2021.104882

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