Imagine discovering a set of footprints on a remote beach, only to later find an identical set thousands of miles away. This is exactly what happened to a team of paleontologists, who uncovered matching dinosaur footprints on opposite sides of the Atlantic Ocean.
Obviously, these dinos weren’t wearing the same kind of shoes, nor was it the case that one dino traveled from one side of an ocean to another. These tracks, uncovered in Brazil and Cameroon, provide new insights into a time when South America and Africa were still joined as part of the supercontinent Gondwana.
The Split of Gondwana
These tracks were found along ancient rivers and lakes in regions now separated by more than 3,700 miles. The remarkable similarity of the footprints, impressed into mud and silt, clearly indicates that dinosaurs once traversed a shared environment.
“We determined that in terms of age, these footprints were similar,” said Southern Methodist University paleontologist Louis L. Jacobs, who led the new study. “In their geological and plate tectonic contexts, they were also similar. In terms of their shapes, they are almost identical.”
Most of the footprints belong to theropods, a group of three-toed carnivorous dinosaurs. Some tracks also suggest the presence of long-necked sauropods and bird-hipped ornithischians.
So what happened? You might have noticed that the coastlines of modern-day Brazil and West Africa fit nicely together like two jigsaw puzzles — this is no accident. South America and West Africa were once part of a massive supercontinent known as Gondwana, which itself was a fragment of an even larger supercontinent called Pangea.
The connection between these two continents can be traced back through the study of plate tectonics, the scientific theory that explains the movement of Earth’s lithospheric plates. Around 180 million years ago, during the Jurassic period, Pangea began to break apart due to the forces generated by the underlying mantle convection currents. This process set the stage for the gradual separation of landmasses that would eventually form the continents we know today.
The research highlights the narrow connection between Africa and South America before the continents drifted apart. Jacobs points to a specific region—northeastern Brazil and the coast of Cameroon along the Gulf of Guinea—as one of the last physical links between the two continents. This narrow stretch allowed animals to migrate freely between what would become South America and Africa.
The final split between South America and Africa started about 140 million years ago, during the Early Cretaceous period. As the tectonic plates carrying these continents moved apart, magma from the Earth’s mantle rose to the surface along a developing rift, forming new oceanic crust and creating what would become the South Atlantic Ocean. His phenomenon, known as “continental drift,” is a direct result of tectonic forces that continue to reshape Earth’s surface.
The footprints discovered in both Brazil and Cameroon are embedded in sediments formed during this continental rifting, containing clues like fossil pollen that date them to 120 million years ago.
What Does This Mean for Our Understanding of Dinosaur Evolution?
This discovery adds a crucial piece to the puzzle of dinosaur evolution and migration. It suggests that these creatures not only lived on interconnected continents but also adapted to a variety of environments across a massive land bridge. This challenges previous assumptions about dinosaur distribution and prompts new questions about how these animals lived and interacted in a shared habitat.
“One of the youngest and narrowest geological connections between Africa and South America was the elbow of northeastern Brazil nestled against what is now the coast of Cameroon along the Gulf of Guinea,” Jacobs explained. “The two continents were continuous along that narrow stretch so that animals on either side of that connection could potentially move across it.”
As South America and Africa began to drift apart, the land bridge between them was gradually eroded, isolating the dinosaur populations on each side.
“Before the continental connection between Africa and South America was severed, rivers flowed and lakes formed in the basins,” he said.
“Plants fed the herbivores and supported a food chain. Muddy sediments left by the rivers and lakes contain dinosaur footprints, including those of meat-eaters, documenting that these river valleys could provide specific avenues for life to travel across the continents 120 million years age.”
The findings were reported in the New Mexico Museum of Natural History and Science Bulletin.
This article originally appeared in August 2024 and was updated with new information before republishing.
