admin In times of isolation like this, last month feels like 100 million years ago. But new research suggests that if you actually travel back in time to Western Sahara, you’re likely to encounter a whole new set of problems: hordes of giant predators.
This area was not a desert, but was covered by a vast system of rivers that flowed through what is now Morocco and Algeria. Interestingly, paleontologists have found very few fossils of the herbivorous dinosaurs that once roamed much of the world. Rather, many of the fossils they identified were ancestors of meat-eating dinosaurs, flying reptiles called pterosaurs, and modern crocodiles.
“It was arguably the most dangerous place in the history of planet Earth because it was home to so many different kinds of predators in all shapes and sizes,” says Nizar Ibrahim, a paleontologist at the University of Detroit Mercy. “This river of giants is unlike any ecosystem today, and in fact it`s also pretty unique compared to other dinosaur age ecosystems.”
Ibrahim and his colleagues have taken a sweeping look at the denizens and geology of this ecosystem, the remnants of which are preserved in the rock formations in eastern Morocco known as the Kem Kem Group or Kem Kem beds. Their report, published on April 21 in the journal ZooKeys, is based on the team`s findings from two decades of expeditions to the area and visits to fossil collections in museums around the world.
“This work represents the first detailed synthesis of all previous works on the geology and the paleontology of the Kem Kem Beds, and the first attempt to reconstruct the environmental conditions in this zone of North Africa between 100 and 95 million years ago,” Andrea Cau, an independent researcher who has collaborated with museums and universities in Italy, the United Kingdom, and elsewhere, told Popular Science in an email.
Although some of the paleontological findings are still preliminary and need to be confirmed by more detailed studies, the report could be a valuable resource for paleontologists on future expeditions to the region. Kaw, who studies the Kem Kem Group and other ancient ecosystems, said there is a lot of potential. in North Africa.
Called the Kem Kem Group, this area consists of sedimentary rock formations exposed on long, winding cliffs near the Moroccan-Algerian border. The fossils found here are varied.
“You get everything from tiny amphibians and delicate plants to giant dinosaurs,” says Ibrahim. Some of these fossils represent herbivorous dinosaurs, such as long-necked sauropods. But these creatures don’t seem to be as common as their carnivorous cousins, and paleontologists have been noticing this pattern at sites across North Africa since the 1930s.
These fearsome beasts included at least four large predatory dinosaurs. One belonged to a group called Abelisauridae. A short snout and relatively small teeth suggest it may have been a scavenger. Paleontologists also describe Spinosaurus, which had a narrow snout and teeth specialized for stabbing and catching fish, a nimble predatory bird about 26 feet long, and a steak-knife-like sawtooth known as Carcharodontosaurus saharicus. They also unearthed the fossil of a giant hunter with teeth. Rex. Meanwhile, 13- to 20-foot pterosaurs flew overhead with wings spread, and shark- and crocodile-like creatures about the length of a school bus roamed the water’s surface.
“If you had visited this place as a human, you would have died in many different ways,” says Ibrahim.
By examining the wide variety of fossils collected from this dire environment, Ibrahim and his team are able to see what the “amazing abundance” of predators is. I wanted to coexist with them and better understand what they were feeding on. The researchers observed that the carnivores of the KemKem group had very different skulls, suggesting that they specialized in eating different types of prey. This could allow predators to avoid each other and not have to compete for the same food. Often these meals were seafood. Fish seems to have been the most abundant food source at the time, with some swimmers reaching the size of SUVs.
In today’s landscape, top predators such as wolves and lions far outnumber herbivorous prey. But even during the Middle Cretaceous, when North Africa was covered by extensive river systems, an ecosystem dominated by so many large predators would have been rare. “In some ways, this is similar to what we see in marine ecosystems, but predators are actually more common,” says Ibrahim.
The landscapes in which these animals lived were filled with winding rivers, lakes and tidal flats. This suggests that the area could not have sustained enough vegetation to sustain large numbers of herbivorous dinosaurs for long periods of time, Ibrahim said.
There may be other reasons why paleontologists have found few large herbivore fossils in the area. Most of the sauropod fossils found in the region are not complete skeletons, but single bones or isolated fragments, making it difficult to determine which species they belonged to, he said. University College London paleontologist Philip Mannion, who was not involved in the study, said in an email. Sauropods tended to have similarly looking teeth, and vertebrae that should be more exposed were often fragile and less likely to be preserved.
“At the end of the day, it’s hard to say [the fossils] don’t reflect greater diversity,” he says. It is also possible that these herbivorous dinosaurs lived and died primarily in other nearby habitats and rarely ventured into areas that happened to be preserved in the KemKem group.
For Ibrahim, the Kem Kem group is a reminder that ecosystems in the past may have been governed by very different rules than we see today. This is not surprising, he says, given that more than 99 percent of all life that has ever existed went extinct before the short period we call it now.
“The Sahara Desert is a wonderful place to be, but when you go out into this dry and desolate place and pick up giant fish scales and crocodile teeth, you really get what you call a deep sense of time.” It gives you a good idea of how much there is on Earth and how much it can change over time.”
