About 200 million years ago, the supercontinent Pangea, which included most of the landmass, began to unravel. This created a great fracture, which separated Africa and Europe from North America and, in time, would give rise to the Atlantic Ocean . However, certain dinosaurs, such as some species of stegosaurus, which lived tens of millions of years later, appear in the fossil record on both sides of the new sea.
Now, the Greek biogeographer Leonidas Brikiatis suggests in a new study that these animals were able to cross it in two moments through two land bridges . As indicated in an article published in the journal Earth-Science Reviews , one would have connected the current Iberian Peninsula with North America between 154 and 151 million years ago, and another would have extended from the latter region to what is now Scandinavia between 131 million years ago. and 129 million years. These estimates appear to correspond to the age of the remains found on both sides of the ocean.
Brikiatis points out that the gap should not have been very deep, although wide enough to prevent land animals from swimming across it. However, tectonic activity could have favored the emergence of strips of land between 80 and 160 kilometers that would allow them to do so. These could be used by some species of reptiles, primitive mammals and dinosaurs, such as certain allosaurs – carnivorous theropods – and supersaurs – large sauropods about 30 meters long.
The rise in sea level would end up flooding these routes. Even so, other experts have questioned this hypothesis . For example, the paleontologist Octávio Mateus, from the New University of Lisbon, points out in the ScienceNews portal that the dinosaurs could have moved through the area highlighted by Brikiatis even before those land bridges were formed.
Gerhard Boeggemann / CC
