An international group of paleontologists has discovered matching Early Cretaceous dinosaur footprints on what are now two separate continents.
A global team of researchers, headed by SMU paleontologist Louis L. Jacobs, uncovered similar sets of Early Cretaceous dinosaur footprints across two continents that are now far apart.
The team identified over 260 footprints located in Brazil and Cameroon, revealing the crossing paths of land-dwelling dinosaurs that roamed freely between South America and Africa millions of years before the continents separated.
“We ascertained that these footprints are of a comparable age,” Jacobs remarked. “Geologically and based on plate tectonics, they show significant similarities. Their shapes are nearly indistinguishable as well.”
The footprints were preserved in mud and silt next to ancient rivers and lakes, situated more than 3,700 miles (or 6,000 kilometers) apart. Dinosaurs made these tracks 120 million years ago when the land formed one supercontinent called Gondwana, which itself had split from the larger landmass of Pangea, according to Jacobs.
“In northeastern Brazil and along what is now the Gulf of Guinea coast in Cameroon, there existed a narrow geological link connecting Africa and South America,” Jacobs explained. “During that time, the two continents were attached in that slender area, enabling animals on either side to migrate across.”
Most of the tracks were made by three-toed theropod dinosaurs, with some potentially created by sauropods or ornithischians, noted Diana P. Vineyard, a research associate at SMU and co-author of the study.
Other co-authors included Lawrence J. Flynn from Harvard University’s Department of Human Evolutionary Biology, Christopher R. Scotese from Northwestern University’s Department of Earth and Planetary Sciences, and Ismar de Souza Carvalho from the Universidade Federal do Rio de Janeiro and Centro de Geociências.
This study was published by the New Mexico Museum of Natural History & Science as a tribute to the late paleontologist Martin Lockley, who dedicated much of his work to studying dinosaur tracks and footprints.
Dinosaur footprints tell the whole story
Africa and South America began to drift apart about 140 million years ago, which caused rifts in the Earth’s crust to form along existing weak spots. As the tectonic plates in these regions separated, magma pushed up from the Earth’s mantle to create new oceanic crust, leading to the gradual filling of the South Atlantic Ocean between the two continents.
Evidence of these significant geological events can be found at both sites of the dinosaur footprints — the Borborema region in northeastern Brazil and the Koum Basin in northern Cameroon. Both areas contain half-graben basins, which are geological formations created during rifting. These basins are filled with ancient river and lake sediments that, alongside the dinosaur tracks, also contain fossilized pollen, dating back 120 million years.
Before Africa and South America were fully separated, “rivers meandered and lakes emerged in these basins,” Jacobs stated. “Vegetation supported herbivores and established a food chain. The muddy sediments from these waterways, which hold dinosaur footprints, including those of carnivorous species, illustrate that these river valleys served as pathways for life across the continents 120 million years ago.”
