Fossils of Two New Abelisaurid Dinosaurs Uncovered in Morocco

Paleontologists have unearthed the fossilized remains of two T. rex cousins in the Ouled Abdoun Basin, northern Morocco.

The two new dinosaur species lived approximately 66 million years ago and had short, bulldog snouts and very short arms.

They belonged to Abelisauridae, a family of carnivorous dinosaurs that were counterparts to the tyrannosaurs of the northern hemisphere.

One of the species was about 2.5 m (8 feet) long and is represented by a fossilized foot bone found near the town of Sidi Daoui.

The other, from nearby Sidi Chennane, measured around 5 m (15 feet) in length and is represented by a shin bone.

“What’s surprising here is that these are marine beds,” said University of Bath paleontologist Nick Longrich.

“It’s a shallow, tropical sea full of plesiosaurs, mosasaurs, and sharks. It’s not exactly a place you’d expect to find a lot of dinosaurs. But we’re finding them.”

The fossils suggest as many as three abelisaurid species coexisted in Morocco around 66 million years ago, showing dinosaurs were highly diverse in North Africa prior to the end-Cretaceous mass extinction.

“The end of the Cretaceous in western North America definitely seems to become less diverse at the end,” Dr. Longrich said.

“But that’s just one small part of the world. It’s not clear that you can generalise from the dinosaurs of Wyoming and Montana to the whole world.”

“It also grew colder near the end, so it might not be surprising if dinosaurs at higher latitudes became less diverse. But we don’t know much about dinosaurs from lower latitudes.”

“In Morocco at least, they seem to have remained diverse and successful up until the end.”

“When T. rex reigned as a megapredator in North America, abelisaurs sat at the top of the food chains in North Africa,” said Professor Nour-Eddine Jalil, a paleontologist at the Natural History Museum and at the Universite Cadi Ayyad.

“The dinosaur remains, despite their rarity, give the same messages as the more abundant marine reptile remains.”

“They tell us that, just before the Cretaceous-Paleogene crisis, biodiversity was not declining but on the contrary, was diverse.”

The team’s paper was published in the journal Cretaceous Research.

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Nicholas R. Longrich et al. New fossils of Abelisauridae (Dinosauria: Theropoda) from the upper Maastrichtian of Morocco, North Africa. Cretaceous Research, published online August 22, 2023; doi: 10.1016/j.cretres.2023.105677