Identical Dinosaur Footprints Found on Opposite Sides of Atlantic Ocean

An international team of researchers led by SMU paleontologist Louis L. Jacobs has discovered matching sets of early Cretaceous dinosaur footprints on what are now two different continents.

More than 260 footprints have been discovered in Brazil and Cameroon, showing where land-dwelling dinosaurs may have last roamed freely across South America and Africa millions of years ago, before the two continents split.

“We determined that in terms of age, these footprints were similar,” Jacobs said. “In their geological and plate tectonic context, they were also similar. In terms of shapes, they are almost identical.”

The footprints, imprinted in mud and silt along ancient rivers and lakes, were found more than 6,000 kilometers (3,700 miles) apart. Dinosaurs left the tracks 120 million years ago on a single supercontinent called Gondwana, which broke away from the larger landmass of Pangaea, Jacobs said.

“One of the youngest and tightest geological connections between Africa and South America was the Northeast Brazilian Elbow nestled against what is now the coast of Cameroon along the Gulf of Guinea,” Jacobs says. “The two continents were continuous along this narrow strip, so animals on either side of this connection could potentially cross it.”

Most dinosaur fossils were created by three-toed theropod dinosaurs. A few were likely created by sauropods or ornithischians, said Diana P. Vineyard, an associate research scientist at SMU and co-author of the study.

Other co-authors of the study were Lawrence J. Flynn of the Department of Human Evolutionary Biology at Harvard University, Christopher R. Scotese of the Department of Earth and Planetary Sciences at Northwestern University, and Ismar de Souza Carvalho of the Federal University of Rio de Janeiro and the Centro de Geociências.

The study was published by the New Mexico Museum of Natural History and Science in honor of the late paleontologist Martin Lockley, who spent much of his career studying dinosaur tracks and footprints.

Dinosaur footprints tell the whole story

Africa and South America began to divide about 140 million years ago, causing cracks in the Earth’s crust, called faults, to open along pre-existing weaknesses.

As the tectonic plates beneath South America and Africa moved apart, magma from the Earth’s mantle rose to the surface, creating new oceanic crust as the continents moved apart. And eventually, the South Atlantic Ocean filled the gap between these two newly formed continents.

Evidence of these major events has been observed in both regions where the dinosaur footprints were discovered, namely the Borborema region in northeastern Brazil and the Koum Basin in northern Cameroon. Semi-graben basins, geological structures formed during rifting, when the Earth’s crust breaks apart and faults form, are found in both regions and contain ancient river and lake sediments.

In addition to dinosaur tracks, these sediments contain fossil pollen that indicates an age of 120 million years.

Before the continental connection between Africa and South America was severed, “rivers flowed and lakes formed in the basins,” Jacobs said.

“The plants fed the herbivores and supported a food chain. The muddy sediments left by rivers and lakes contain dinosaur footprints, including those of carnivores, which proves that these river valleys may have provided specific pathways for life to cross continents 120 million years ago.”