Prehistoric Sahara Filled With Ferocious Predators Was 'Most Dangerous Place in the History of Planet Earth,' Scientists Say

Around 100 million years ago, an area of the Sahara in what is now south-eastern Morocco was home to a frightening array of ferocious predators, so much so scientists have dubbed it "most dangerous place in the history of planet Earth."

In a paper published in the journal ZooKeys, a team of scientists reviewed an assemblage of fossils found in ancient rock formations known as the Kem Kem group, located near the border between Morocco and Algeria on the northwestern edge of the Sahara Desert.

The Kem Kem group provides a "window into Africa's Age of Dinosaurs," lead author Nizar Ibrahim, a biologist from the University of Detroit Mercy and a visiting researcher at the University of Portsmouth, U.K., said in a statement.

The fossils, which are now held in collections around the world, include those of large dinosaurs, pterosaurs, crocodilians, turtles, fish, invertebrates and plants, according to the researchers.

Among the fossils are three of the largest predatory dinosaurs known to science. These included Carcharodontosaurus—a group that includes dinosaurs with serrated teeth, some of which measured over 40 feet in length—and Deltadromeus, a group of large raptors with long, slender hind limbs.

"This was arguably the most dangerous place in the history of planet Earth, a place where a human time-traveler would not last very long," Ibrahim said in a statement.

While this is a dry, arid region today, 100 million years ago when these creatures lived, the area was home to a vast river system with a tropical climate and an abundance of aquatic and terrestrial animals, according to the researchers. Many of these predators likely relied on the numerous fish that filled the waters of this river system.

"This place was filled with absolutely enormous fish, including giant coelacanths and lungfish. The coelacanth, for example, is probably four or even five times large than today's coelacanth," David Martill, another author of the study from the University of Portsmouth, said in the statement.

"There is an enormous freshwater saw shark called Onchopristis with the most fearsome of rostral teeth, they are like barbed daggers, but beautifully shiny."

Kem Kem group fossils
Artist's illustration of Kem Kem group animals. University of Portsmouth

According to the researchers, no comparable modern terrestrial ecosystem exists that is so dominated by large carnivores. In fact, the Kem Kem group contains at least four types of large, predatory dinosaurs, three of which are among the largest dinosaurian predators on record.

Furthermore, large-bodied herbivores are not well-represented in the Kem Kem group fossils. This overabundance of predatory to herbivorous dinosaurs is known as Stromer's Riddle, named after the German paleontologist Ernst Stromer who first noticed the phenomenon in the early 20th century.

According to the study, the Kem Kem assemblage is mostly dominated by aquatic and semi-aquatic animals.

"Most of the described vertebrates, with the exception of some of the pterosaurs and dinosaurs, lived exclusively or predominantly within an aquatic setting, which would include pond, river, delta, and nearshore habitats," the authors wrote in the paper. "Most of the [groups] in the assemblage, thus, are predators utilizing aquatic food resources as in modern marine food webs."