The primitive cousins of the Tyrannosaurus rex had bulldog snouts and even shorter arms, reveals a new study.
Scientists say that fossils recently discovered just outside Casablanca in Morocco shed new light on the end of the age of dinosaurs in Africa.
The two new species belong to the Abelisauridae – a family of meat-eating dinosaurs that were counterparts to the tyrannosaurs of the Northern Hemisphere.
Paleontologists say they lived at the end of the Cretaceous period and show that dinosaurs were “diverse” in Africa just before their mass extinction 66 million years ago.
One species, found near the town of Sidi Daoui, is represented by a foot bone from a predator about 2.5 meters (eight feet) long.
The other, from nearby Sidi Chennane, is the shin bone of a carnivore that grew to around five meters (15 feet) in length, according to the findings published in the journal Cretaceous Research.
Scientists say both species lived alongside the much larger abelisaur Chenanisaurus barbaricus, showing that Morocco was home to numerous dinosaur species just before a giant asteroid struck at the end of the Cretaceous.
Study leader Dr. Nick Longrich, from the Milner Centre for Evolution at the University of Bath, said: “What’s surprising here is that these are marine beds.
“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.”
He said that even though dinosaurs account for a small proportion, the region is so rich in fossils that it has produced the best picture of the end of the dinosaur age in Africa.
Dr. Longrich said that, rather than finding the same few species, paleontologists often recover fossils from new species, suggesting the beds host an “extremely diverse” dinosaur fauna.
So far, the small number of dinosaur fossils that have been recovered represent five different species – a small duckbill dinosaur named Ajnabia, a long-necked titanosaur, the giant abelisaur Chenanisaurus, and now the two new abelisaurs.
Dr. Longrich said: “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.”
The last dinosaurs vanished around 66 million years ago, along with as much as 90 per cent of all species on Earth.
The pattern of the end-Cretaceous extinction and its causes have been debated for over 200 years.
A giant asteroid impact in the Yucatan peninsula has been linked to the demise of dinosaurs, although it has been argued that they were already in decline.
Dr. Longrich says the Moroccan dinosaurs suggest that they “thrived” in North Africa up to the very end.
He added: “The end of the Cretaceous in western North America definitely seems to become less diverse at the end.
“But that’s just one small part of the world. It’s not clear that you can generalize 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.”
He said that, in Morocco at least, they seem to have remained diverse and successful up until the end.
Study co-author Professor Nour-Eddine Jalil, of Universite Cadi Ayyad in Morocco, said: “When T. rex reigned as a megapredator in North America, abelisaurs sat at the top of the food chains in North Africa.
“The dinosaur remains, despite their rarity, give the same messages as the more abundant marine reptile remains.”
He added: “They tell us that, just before the Cretaceous-Paleogene crisis, biodiversity was not declining but on the contrary, was diverse.”
Produced in association with SWNS Talker
