In an astonishing discovery that has captivated paleontologists worldwide, matching sets of dinosaur footprints from the Early Cretaceous period have been unearthed on two different continents—South America and Africa—offering unprecedented insights into Earth's geological past. These footprints, more than 260 in total, provide strong evidence of the last connections between these landmasses before they were split apart by the opening of the South Atlantic Ocean nearly 120 million years ago.
Discovered in Brazil’s Sousa Basin and Cameroon’s Koum Basin, these footprints represent an extraordinary find that ties together the histories of two continents that were once part of the supercontinent Gondwana. The discovery suggests that dinosaurs were able to roam freely across these regions before the continents were severed by the tectonic forces that created the ocean that separates them today. Paleontologists believe that the footprints were left by a variety of dinosaurs, including theropods, sauropods, and ornithischians, who traversed the land bridge connecting Africa and South America during this prehistoric era.
A Glimpse Into Earth's Ancient Past
The discovery of these matching dinosaur footprints is not only a testament to the incredible movement of Earth's landmasses but also offers a rare glimpse into the lives of the creatures that roamed the ancient supercontinent. According to Louis L. Jacobs, a paleontologist at Southern Methodist University (SMU) who led the research, “We determined that in terms of age, these footprints were similar. In their geological and plate tectonic contexts, they were also similar. In terms of their shapes, they are almost identical.”
The identical nature of the footprints on both sides of the Atlantic provides a vivid reminder of a time when Africa and South America were still connected, allowing land-dwelling dinosaurs to migrate freely between the two regions. These tracks were preserved in mud and silt deposits along ancient rivers and lakes, creating fossilized records of dinosaur movement in areas that today are separated by more than 3,700 miles of ocean.
The region where these footprints were found corresponds to a narrow land bridge that once linked northeastern Brazil with Cameroon. This ancient land bridge provided a critical pathway for dinosaurs and other species to migrate between the two continents before the final separation occurred. As the Earth’s tectonic plates continued to shift and the supercontinent began to break apart, this land bridge was submerged, and the South Atlantic Ocean was formed, permanently dividing the continents and severing the migration routes.
Geological Evidence Supports the Footprint Discovery
In addition to the footprints themselves, researchers discovered fossil pollen in the same sediment layers, further dating the tracks to around 120 million years ago. The tracks were found in geological formations known as half-graben basins, which were created as the Earth's crust began to pull apart during the continental rifting process. These basins contain layers of ancient river and lake deposits that offer a wealth of information about the environment in which these dinosaurs lived.
“These river valleys could provide specific avenues for life to travel across the continents 120 million years ago,” explained Jacobs. The rivers and lakes in these basins supported thriving ecosystems, with lush vegetation that fed herbivorous dinosaurs and other species, while muddy sediments preserved the footprints of carnivorous theropods and other creatures. These tracks are significant not only because they offer a window into the past but also because they reveal the critical role these river systems played in connecting the two landmasses.
The geological formations in which the tracks were found provide critical clues about the environment during the final days of Gondwana. As the landmasses drifted apart, magma from the Earth’s mantle began to rise, forming new oceanic crust and eventually filling the gap with water to create the South Atlantic Ocean. The footprints found in the basins are among the last physical evidence of the dinosaurs' movement between the continents before this vast ocean severed the connection forever.
The Broader Implications for Continental Drift and Dinosaur Migration
The discovery of these dinosaur footprints on opposite sides of the Atlantic offers compelling new evidence of the dramatic changes that shaped Earth’s surface over millions of years. The study, which was published by the New Mexico Museum of Natural History & Science, is a tribute to the late paleontologist Martin Lockley, whose pioneering work in ichnology (the study of fossilized footprints) laid the groundwork for understanding these ancient migrations.
These footprints are not just marks in the ground; they are direct evidence of how plate tectonics and continental drift have shaped life on Earth. By studying these tracks and the geological contexts in which they were found, researchers can better understand how species adapted to and navigated changing environments over time. The fact that these tracks are almost identical on both continents suggests that the same species of dinosaurs roamed freely across the land bridge before being separated by the forming ocean.
The findings also emphasize the significance of Gondwana’s fragmentation and how the movement of Earth's tectonic plates led to the isolation of species on different continents, ultimately driving evolutionary changes. As the South Atlantic Ocean formed, species on both continents began to evolve independently, leading to the biodiversity we see today. This discovery underscores the importance of studying the fossil record to understand the dynamic forces that have shaped our planet's biological and geological history.