Remains of dinosaur fossils recently discovered in the Sahara desert in Morocco are strikingly similar to the giant carnivorous dinosaur Tyrannosaurus rex
Remains of dinosaur fossils recently discovered in the Sahara desert in Morocco are strikingly similar to the giant carnivorous dinosaur Tyrannosaurus rex, the huge monster that scared the viewers in "Jurassic Park", and lived about 70 million years ago in North America. The great similarity points to a common origin of the two carnivores and it indicates that Africa was not completely separated from the northern continents at that time, and the dinosaurs could migrate from place to place.
A giant dinosaur skull was the most dramatic find uncovered in the Sahara by two expeditions of paleontologists (researchers of fossils) from the University of Chicago. Until then, not much was known about the dinosaurs that lived in Africa.
Of the hundreds of species of dinosaurs identified so far around the world, only a few could probably exist in such remote and hostile regions as Africa. "We know very little about the dinosaurs that lived in Africa in the Cretaceous, the period that marked the age of the dinosaurs. Most of the evidence from this period came from North America and Asia. The fossils discovered in Morocco allow us for the first time to examine the nature of the carnivores that evolved on the isolated continent of Africa," says Paul Sarno, who headed the expeditions.
Sarno became interested in the evolution of dinosaurs in Africa in 1990 when he joined a group of paleontologists from the British Museum that went looking for fish fossils in Nigeria. "Then we discovered a burial complex of dinosaurs the size of a basketball court with huge bones buried in the sand. One of the chest bones reached a length of two meters," Serno says. The findings ignited his imagination and he decided to organize an excavation expedition to the area.
After three years of planning, he managed to lead a group of 21 scientists and students back to Nigeria. In six Land Rovers loaded with equipment, they crossed more than 2,500 kilometers of the Shakhon desert and spent two months searching for the remains of the dinosaurs that lived there. "When we brushed the sand sediments over the buried remains, to our surprise we discovered well-preserved bones," Sarno says. "The skeleton was preserved as if these giant animals had been resting there quietly for millions of years. It seems that they were buried in a sudden flood of an ancient river." About a year ago Serano led another expedition that excavated near the Morocco-Algiers border. The uncovered skull, which is more than one and a half meters long, is larger than the skull of Tyrannosaurus rex, which lived 70-65 million years ago in North America, and is considered the largest predator among the giant lizards that ruled the Earth in the Jurassic and Cretaceous eras. Sarno named the skull Carcharodontosaurus saharicus, which means "the shark-toothed reptile of the Sahara". Its brain cavity is well preserved and reaches half the brain size of Tyrannosaurus Rex (15th the size of a human brain). It probably fed on small plant-eating dinosaurs. Sarno estimates its length at about 14 meters.
The fossils that were uncovered solved a mystery of fossilized bones and teeth that were discovered in Egypt at the beginning of the century and were destroyed in World War II. No one knew who they belonged to, but the teeth in the giant skull found in Morocco matched the description of the teeth found in Egypt, and they apparently belonged to the same type of dinosaur discovered by Sarno.
When the dinosaurs appeared about 230 million years ago during the Triassic period, all the continents were connected together in a supercontinent known as Pangea. Free-roaming dinosaurs were similar everywhere on the continent.
80 million years later, towards the end of the Jurassic period, the Pangea continent broke into two subcontinents: a northern continent - Eurasia, and a southern continent - Gondwana, with the ancient Tethys Ocean between them. During the next geological period - the Cretaceous - 146 to 65 million years ago, the continents moved away from each other and eventually reached their current location.
At the time when the dinosaur that was discovered in Africa appeared, about 90 million years ago, the world appeared as a patchwork of isolated continents, each with its own dinosaur forms, which developed separately after being separated from each other. Like all forms of life, the different species of dinosaurs also evolved and changed over the years according to the conditions of the place where they lived. This is how human-sized carnivorous dinosaurs evolved in Mongolia, rhinoceros-like vegetarian dinosaurs in North America, and more.
Until recently, no one knew what the dinosaurs looked like in Africa. For many years, scientists believed that the dinosaurs evolved from two groups: a northern group originating in Laurasia, and a southern group originating in Gondwana. The basis for this idea were finds of strange dinosaurs discovered in South America. These dinosaurs, with a pair of horns above their eyes, were unlike any of the northern dinosaurs.
Because Africa and South America were included in the continent of Gondwana, and both were isolated from northern Eurasia, scientists assumed that the dinosaurs in Africa would be different from the northern ones but similar to their South American counterparts. The remains of the dinosaur found in Africa turned the theory upside down, in that they were not similar to the South American predator but rather to the giant dinosaur that lived in North America during the early Cretaceous period.
What can explain the similarity between the early Cretaceous African dinosaurs and those from the northern continents? Sarno believes that land bridges or shallow sea areas remained between Eurasia and Gondwana after they broke off from each other. These areas allowed the migration of dinosaurs from continent to continent and this explains the similarity between certain dinosaur species in the world.
After Africa and South America separated from the northern continents, they began to separate from each other and the Atlantic Ocean stretched between them. This happened about 90 million years ago. On each of the two continents, some dinosaurs became extinct and some survived. One of the survivors was the dinosaur whose remains were found in Morocco last year. From then on, the African dinosaurs continued to develop in complete isolation - this is what Sarno believes, who wants to return to Africa in a few years and look for findings that will substantiate his hypotheses. According to Sarno, the story of the dinosaurs in Africa has only just begun.
("Haaretz" 31/07/96) - The Hidan site was until 2002, part of the IOL portal from the Haaretz group
