T. rex cousins discovered in Morocco shed light on last dinosaurs in Africa

Fossils of two newly discovered carnivorous dinosaurs have been found in Morocco. The animals lived at the end of the Cretaceous period just before the mass extinction event 66 million years ago, and show dinosaurs were diverse in Africa before going extinct.

Both predators belong to a primitive family known as abelisaurids. These dinosaurs were bipedal theropods with very short, vestigial arms (even shorter than Tyrannosaurus rex) and short bulldog-like snouts.

Among the most famous abelisaurids is the two-horned Carnotaurus which would have been about 8 metres in length.

While North America and east Asia were dominated by tyrannosaurine giant predators like T. rex and Tarbosaurus, abelisaurids were widespread across Africa, south Asia, Madagascar and South America.

One of the new Moroccan abelisaurids was found in Sidi Chennane, just outside Casablanca. It is known from a fossilised shin bone which suggests a medium-sized carnivore about 5 metres long.

The other was found at Sidi Daoui, also near Casablanca, but would have been much smaller at about 2.6 metres in length.

Both are described in a paper published in the journal Cretaceous Research.

The newly discovered dinosaurs lived alongside another abelisaurid first described in 2017. That animal, Chenanisaurus barbaricus, would have been larger than both, measuring up to 8 metres.

That Morocco supported three different abelisaurid species just before the Cretaceous mass extinction suggests that African dinosaurs were diverse just before the asteroid that wiped out more than two-thirds of life on Earth crashed into what is now the gulf of Mexico.

Another surprising fact about the discoveries is that they’re being made in an area that was once the seabed.

“It’s a shallow, tropical sea full of plesiosaurs, mosasaurs, and sharks,” says lead researcher Dr Nick Longrich from the University of Bath, UK. “It’s not exactly a place you’d expect to find a lot of dinosaurs. But we’re finding them.”

In addition to the abelisaurids, the sites in the area have turned up a small duck-billed dinosaur called Ajnabia and long-necked titanosaur fossils.

“We have other fossils as well, but they’re currently under study. So we can’t say much about them at the moment, except that this was an amazingly diverse dinosaur fauna,” Longrich adds.

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