The final chapter of dinosaur history is a story spanning two very different worlds, each of which is a vast supercontinent dominated by a unique combination of carnivores and animals. herbivorous.
The fossil remains of a herbivore common to one of the two main lands were unexpectedly unearthed in the rocks belonging to the other, prompting paleontologists to question how it was. can make such a leap.
“It’s completely out of place, like finding a kangaroo in Scotland,” said paleontologist Nicholas Longrich of the University of Bath, who leads a study on the recent discovery.
This misplaced ‘kangaroo’ is actually a kind of newly classified crest speculum, called hadrosaurid (belonging to a genus lambeosaurine to be exact).
About 66 million years ago, when the Cretaceous period was about to end the great cataclysm, the dinosaur of many different breeds was one of the most popular herbivorous dinosaurs.
At least that was the case with the Laurasia supercontinent ̵1; a block that would later split apart to give us today’s continents of North America, Europe and much of Asia.
On the other side of the ocean, a separate land called Gondwana is instead ruled by a variety of long, slow-necked sauropods.
Relics of these giants are often found in places like Africa, India, Australia and South America.
Where Hollywood might find fit to bring the two groups together, the wide expanse of water between the continents and long periods of isolation meant that by the end of the Cretaceous period, the ducks and the long necks would only be able to mix import in separate regions, such as where is today Europe.
This newest member of the hadrosaurid family may be a new exception.
Based on some fragments of the jawbone and a handful of teeth extracted from a phosphate mine in Morocco, the finding is proof that at least one of these animals had to be more likely than ever to wander out of Laurasia .
Well, maybe not wandering around, rowing so much.
“It is impossible to walk to Africa,” said Longrich.
“These dinosaurs evolved long after continental drift split continents and we have no evidence of land bridges. Geology tells us Africa is isolated. by the oceans. If so, the only way to get there is by water. “
This idea is not as far-fetched as initially imagined. Hadrosaurs appear to be at home close to water and come in all shapes and sizes. Some are up to 15 meters (45 feet) long, with large tails and strong legs capable of making them proficient swimmers.
At less than 3 meters (9 feet) in length, this dinosaur could have had a little more difficulty doing a marathon that could cover hundreds of kilometers of water outdoors.
But the hypothesis of smaller animals quickly crossed the ocean on floating rafts with lots of vegetation – why not a relatively small dinosaur?
“Events that happen in a century are likely to happen many times,” Longrich said. The crossing of the ocean is needed to explain how lemurs and hippos get to Madagascar, or how monkeys and rodents cross the sea. from Africa to South America “.
Combining the Arabic word for foreigners with the name of the famous Greek seafarer, the scientists named the dinosaurs Ajnabia odysseus.
The same set contains Ajnabia Jaws abandoned a number of other rare dinosaur bones, including the backbone of the Gondwana dinosaur and the carnivorous arthropod known as the abelisaurs.
It may not be enough to re-imagine the Cretaceous supercontinent splits in the moments before an asteroid changed everything. But it will give us enough time to confirm that the ocean will be an insurmountable barrier.
“As far as I know, we were the first to propose dinosaur crossings,” said Longrich.
This research has been published in Research in the Cretaceous period.