The remains of a new species of plant-eating dinosaur have been unearthed in northern Zimbabwe. It is part of a massive fossil group of the Late Triassic and can help us understand how the climate of the period affected the dispersal of early dinosaurs.
This nearly complete fossil is the oldest dinosaur fossil ever found in Africa. It has been identified as a species of Proboscis, an ancestral relative of Proboscis: it was a huge, long-necked, four-legged dinosaur.
Named Mbiresaurus raathi, the dinosaur was at least a meter tall, ran on two legs, weighed about 30 kilograms, had a small head, a long neck and jagged leaf-like teeth.
Christopher Griffin of Yale University in the United States said it was unearthed the day after an expedition to Mbire in the Zambezi Valley in 2017, and he found a dinosaur femur sticking out of the ground, digging around it, and found a hip bone.
"I continued to dig and got more players to help, and we almost found the whole skeleton," he said. "The rocks it found were interpreted as river sediments, which may have been buried in a small flood."
Based on the presence of other fossils in the group, the research team will M. The raathi is dated about 230 million years ago and is part of the Late Triassic, known as the Karnian stage. At that time, Zimbabwe was further south than it is now and part of the huge supercontinent Pangea.
Scientists believe that latitude plays a large role in Pangea's climate because the ocean's impact on a single landmass is reduced. High latitudes, such as Where Zimbabwe was at the time, may have had greater humidity and abundant vegetation, contrasting with drier, more unstable lower latitudes.
These climate zones are thought to have controlled the range of activities of early dinosaurs, most of which lived in temperate climates in southern Pangea. Dinosaurs are thought to have avoided the harsh deserts of the northern part of this region because they didn't quite fit in there.
"We expect that at this time you can draw a straight line connecting northern Argentina, southern Brazil and India, and everywhere along this line will have a very similar climate." Griffin said: "This imaginary line runs right through Zimbabwe. "
Griffin and his team used this climate line to help identify possible sources of fossils. Their second clue about the location came from a 1992 paper by Michael Russ that reported a fossil of a rhomboid dragon found in the Pebbly Arkose formation in the Dand region of northern Zimbabwe, a Karni-stage reptile.
Raath also reported a bone fragment that he thought might have come from an early dinosaur. These discoveries mean that Zimbabwe has rocks of the right age to preserve fossils from this era.
The team used geological maps of the area to determine the location of these rocks, and used satellite photos of Google Earth to determine where they were exposed to the surface, and then went to the site to look for fossils.
At one site, researchers found hundreds of bones, mostly from rhyosaurs, but also fragments of what they believe to be dinosaurs. It was here that Griffin discovered the protruding femur.
During two expeditions in 2017 and 2019, a group of animal remains were found, including the large carnivorous herrasaurid dinosaur, a mammalian ancestor called cynodonts, and a crocodile ancestor called etosaurs.
Zimbabwe's Zambezi River Valley is already famous for its occasional trail of dinosaur bones and footprints, but M. Raathi is older.
Griffin said: "This means that Zimbabwe has documented the transition from the earliest dinosaurs, when they were relatively rare, to the time when dinosaurs became more abundant and major." "
Anusuya Chinsamy-Turan of the University of Cape Town in South Africa says the latest findings provide a unique perspective on the animal diversity that existed in that region of northern Zimbabwe 230 million years ago.
"The fact that the fauna is similar to other similar-age Karnian deposits in Argentina and Brazil and India strongly supports the hypothesis that the distribution may be related to climate barriers," she said. "
In July, she and her colleagues described a new Iyuku raathi found in the Eastern Cape, South Africa. She said the two dinosaur discoveries from Africa were announced a month apart, which was "huge.".
The new discovery of Fossils in Zimbabwe comes when Australian company Invictus expects to begin exploring for oil and gas drilling in large areas of the Cabora Bassa Basin next month, an area rich in fossil-rich rock deposits.
Chinsamy-Turan said: "I sincerely hope that the necessary protocols have been put in place to guarantee the safety of the fossils, as well as the recovery after exploration. "