First fossil of a duck-billed dinosaur discovered in Africa

Duck-billed dinosaurs evolved in North America, spreading to South America, Asia, Europe, and eventually Africa. Credit: Raul Martin

The first fossils of a duck-billed dinosaur were discovered in Africa, suggesting that the dinosaurs crossed hundreds of kilometers of open water to get there.

The study, published in Cretaceous Research, bring back the new dinosaur, Ajnabia odysseus, from rocks in Morocco dating from the late Cretaceous, 66 million years ago. Ajnabia was a member of the duck-billed dinosaurs, several plant-eating dinosaurs that grew up to 15 meters in length. But the new dinosaur was tiny compared to its relatives: just 3 meters long, it was the size of a pony.

Duckbills evolved in North America and eventually spread to South America, Asia, and Europe. Since Africa was an island continent in the late Cretaceous, isolated by deep sea routes, it seemed impossible to get there for the duck’s beaks.

The discovery of the new fossil in a mine just hours from Casablanca was “the last thing in the world you would expect,” said Dr Nicholas Longrich, of the Milner Center for Evolution at the University of Bath, who led the study . Dr Longrich said: “It was completely out of place, like finding a kangaroo in Scotland. Africa was completely isolated from water, so how did they get there? “

Silhouette showing Ajnabia’s size relative to humans and contemporary fauna of Morocco’s Maastricht dinosaurs. Credit: Dr Nick Longrich

Study of AjnabiaThe distinctive teeth and jawbones show that it belonged to Lambeosaurinae, a subfamily of duckbills with elaborate bony head crests. Lambeosaurs evolved in North America before spreading to Asia and Europe, but they have never been found in Africa before.

By reconstructing the evolution of the duck bill, they found that lambeosaurs evolved in North America, then spread over a land bridge to Asia. From there they colonized Europe and finally Africa.

Since Africa was secluded by deep oceans at the time, duckbills must have traversed hundreds of kilometers of open water, rafting on debris, floating or swimming, to colonize the continent. Duckbills were likely powerful swimmers – they had wide tails and powerful legs and are often found in river deposits and sea rocks, so they may have simply swam for distance.

“Sherlock Holmes said, once the impossible is eliminated, whatever remains, no matter how improbable, must be the truth,” Longrich said. “It was impossible to walk in Africa. These dinosaurs evolved long after continental drift divided continents and we have no evidence of land bridges. Geology tells us that Africa was isolated from the oceans. If so, the only way to get there is water. “

In reference to this feat, the dinosaur is called “Ajnabia odysseus.“Ajnabi means” foreigner “in Arabic and Odysseus refers to the Greek seafarer.

Map showing the location of duck-billed dinosaurs during the Late Cretaceous period. Credit: Dr. Nick Longrich

Ocean crossings are rare and unlikely events, but they have been observed in historical times. In one case, green iguanas traveled between Caribbean islands during a debris-borne hurricane. In another, a Seychelles tortoise floated hundreds of kilometers across the Indian Ocean to reach Africa.

“Over the course of millions of years,” Longrich said, “events once in a century are likely to happen many times over. Ocean crossings are necessary to explain how lemurs and hippos got to Madagascar, or how monkeys and rodents have passed from Africa to South America “.

But the fact that duckbills and other groups of dinosaurs spread across continents, even with a high sea level, suggests that dinosaurs also traveled across oceans. “As far as I know, we are the first to suggest ocean crossings for dinosaurs,” said Longrich.

The international team of scientists was led by the University of Bath with researchers from the University of the Basque Country UVP / EHU (Spain), George Washington University (USA) and the Natural History Museum of Sorbonne University (France) / Universite Cadi Ayyad (Morocco).

Dr Nour-Eddine Jalil, from the Natural History Museum of the Sorbonne University (France) said: “The succession of unlikely events (crossing of an ocean by a dinosaur, fossilization of a terrestrial animal in a marine environment) highlights the rarity of our find and therefore its importance.

“Ajnabia it shows us that hadrosaurs have set foot on African land, telling us that ocean barriers are not always an insurmountable obstacle “.

Reference: “The first duckbill dinosaur (Hadrosauridae: Lambeosaurinae) from Africa and the role of oceanic dispersal in dinosaur biogeography” by Nicholas R. Longrich, Xabier Pereda Suberbiola, R. Alexander Pyron and Nour-Eddine Jalil, 2 November 2020, Cretaceous research.
DOI: 10.1016 / j.cretres.2020.104678