A Cretaceous gang — made up of a large, long-necked dinosaur; a raccoon-size mammal; and a crocodilelike creature — plodded toward a freshwater lake during the Early Cretaceousperiod 118 million years ago, leaving their footprints behind in a sedimentary band of earth.
It’s possible that the animals satiated their thirst at different times, but left their track marks all in the same area, the researchers said.
The ancient track marks were discovered at Angola’s Catoca diamond mine, the fourth-largest diamond mine in the world. The mammalian tracks are a particularly rare find, as most warm-blooded animals at that time were no larger than rats, and this one appears to be larger, researchers said.
“Mammals evolved from very small-sized individuals,” said Marco Marzola, a paleontologist with the PaleoAngola Project, an international program investigating vertebrate paleontology in Angola. “The first mammals were the size of a squirrel or even smaller, like a mouse. They evolved to become bigger in size, but only after the time of the dinosaurs.”
Geologist Vladimir Pervov, who works for the Sociedade Mineira de Catoca, first spotted the 69 animal tracks in December 2010. In addition, 18 dinosaur tracks, likely from a sauropod, and one with preserved skin impressions, were found in two nearby tracks.(Sauropods were long-necked dinosaurs and the largest animals ever to walk the Earth.)
But the ground is hard and cold in December, making the tracks difficult to study. Pervov contacted the scientists working on the PaleoAngola Project, who then asked representatives for the diamond mine to help them preserve the footprints.
“Incredibly, the society of Catoca stopped all activity in that sector of the mine,” Marzola told Live Science. “(They) renounced potential income from their own mine just to promote science — to promote vertebrate paleontology in Angola and in Africa.”