Researchers in the United States and Brazil have confirmed that dinosaur footprints in South America and Africa belong to the same Early Cretaceous species. Though the two continents are now an ocean apart, the tracks indicate that a natural bridge once connected them, offering opportunities for prehistoric migration.
In a release published Friday, paleontologists at Southern Methodist University (SMU) in Texas shared that the footprints march through both Brazil and Cameroon. Though Brazil makes up most of the eastern portion of South America and Cameroon is wedged into Africa’s western joint, the regions were once much closer together. From the Late Ediacaran period to Early Cretaceous period—spanning 600 million to 100 million years ago—Earth boasted fewer (but larger) landmasses. The landmass through which South America and Africa were once fused is now referred to as Gondwana.
But Gondwana didn’t remain one solid block of land for 500 million years. It evolved along with the rest of our planet, resulting in the eventual separation of what we now consider two continents. During the Late Jurassic and Early Cretaceous periods, Gondwana really began to split apart, making it difficult for dinosaurs to travel between the two new landmasses—or so we thought.
Left: Theropod track from the Sousa Basin. Right: Theropod track from the Koum Basin.
Credit: Left: Ismar de Souza Carvalho. Right: SMU
“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,” said SMU paleontologist Louis Jacobs. “The two continents were continuous along that narrow stretch, so that animals on either side of that connection could potentially move across it.”
Jacobs, along with colleagues in the US and Brazil, found that one such migrating species belonged to the Therapoda clade. This vast clade consists of many extant species, all of which survive under the aves (bird) class, but was once ruled by bipedal and carnivorous dinosaurs. Paleontologists found dozens of therapod tracks in Brazil’s Sousa Basin, then dozens more in Cameroon’s Koum Basin. Though the track sets are more than 3,700 miles away from each other, the team was able to demonstrate in a paper that they likely belonged to the same migrating species.
“We determined that in terms of age, these footprints were similar,” Jacobs said. “In their geological and plate tectonic contexts, they were also similar. In terms of their shapes, they are almost identical.”