Ledumahadi mafube – the new Jura giant of South Africa

A new giant dinosaur species has been found in the Free State Province of South Africa. The dinosaur that feeds on plants, named Ledumahadi mafube, weighed 12 tons and was about four meters tall at the hips. Ledumahadi mafube was the largest land animal living on Earth nearly 200 million years ago. It was about twice the size of a big African elephant.

A team of international scientists, led by Professor Jonah Choiniere, paleontologist at the University of the Witwatersrand (Wits), described the new species in the review. Current Biology aujourd & # 39; hui.

The dinosaur calls Sesotho for "a giant thunderclap at dawn" (the sesotho is one of the 11 official languages ​​of South Africa and an indigenous language in the region where the dinosaur was found).

"The name reflects the large size of the animal as well as the fact that its lineage first appeared in sauropod dinosaurs," Choiniere said. "It honors both the recent and ancient heritage of southern Africa."

Ledumahadi mafube is one of the closest relatives of sauropod dinosaurs. Sauropods, weighing up to 60 tons, include well-known species such as brontosaurus. All sauropods ate plants and stood on all fours, with posture like that of modern elephants. Ledumahadi developed its giant size independently of the sauropods, and although it stood on all fours, its forelegs would have been more squatting. This led the scientific team to consider Ledumahadi as an evolutionary "experience" with a giant body size.

The Ledumahadi fossil tells a fascinating story not only of its individual life story, but also of the geographical history of its place of residence and the evolutionary history of the sauropod dinosaurs.

"The first thing that struck me about this animal is the incredible sturdiness of the limb bones," said lead author Dr. Blair McPhee. "It was similar in size to the gigantic sauropod dinosaurs, but while the arms and legs of these animals are usually quite thin, the Ledumahadi are incredibly thick, and for me the path to gigantism among the sauropodomorphs was far from perfect. The way these animals solved the usual problems of life, such as eating and moving, was much more dynamic within the group than previously thought. "

The research team has come up with a new method, using measurements of the "arms" and "legs" to show that Ledumahadi walked on all fours, like later sauropod dinosaurs, but unlike many of them. other members of his group like Massospondylus. The team also showed that many parents of sauropods were on all fours, that this posture was evolving more than once and that it was appearing earlier than scientists thought.

"Many giant dinosaurs walked on all fours but had ancestors walking on two legs.Scientists want to know about this evolutionary change, but surprisingly, no one has found a simple way to tell how each dinosaur walked up and down. now, "says Dr. Roger Benson.

By analyzing the bone tissue of fossils through an osteohistological analysis, Dr. Jennifer Botha-Brink of the South African National Museum of Bloemfontein established the age of the animal.

"By observing the fossilized bone microstructure, we can say that the animal has grown rapidly up to adulthood." Growth rings deposited at the periphery and spaced each year show that the growth rate has decreased dramatically by the time of his death, "says Botha-Brink. This indicates that the animal had reached adulthood.

"It was also interesting to see that the bone tissues have aspects of both basal sauropodomorphs and more derived sauropods, showing that Ledumahadi represents a transitional stage between these two major groups of dinosaurs."

Ledumahadi lived in the vicinity of Clarens, Free State Province, South Africa. It is currently a picturesque mountainous region, but it was very different at that time, with a flat, semi-arid landscape and shallow and dry water courses.

"The properties of sedimentary rock layers in which bone fossils are preserved date back 200 million years." Most of South Africa was much more similar to the current Musina region in Limpopo Province in South Africa. Karoo, "says Dr. Emese Bordy.

Ledumahadi is closely related to other gigantic dinosaurs of Argentina that lived in a similar time, which reinforces the fact that the supercontinent of Pangea was still assembled in the lower Jurassic. "It shows how easily dinosaurs could travel from Johannesburg to Buenos Aires at that time," explains Choiniere.

South Africa's Minister of Science and Technology, Mmamoloko Kubayi-Ngubane, said the discovery of this dinosaur underscores how important South African paleontology is to the world.

"Not only does our country hold the cradle of humanity, but we also have fossils that help us understand the appearance of gigantic dinosaurs." This is another example of South Africa making scientific advances its advantage geographical, as is the case in astronomy, marine and polar research, indigenous knowledge and biodiversity, "says Kubayi-Ngubane.

Ledumahadi's research team includes South African Paleoscientists Dr. Emese Bordy and Dr. Jennifer Botha-Brink, respectively from the University of Cape Town and the South African National Museum in Bloemfontein.

The project also had a strong international component with the collaboration of Professor Roger BJ Benson from Oxford University and Dr. Blair McPhee, currently residing in Brazil.

"South Africa employs some of the world's best paleontologists and it was a privilege to be able to create a working group with them and leading researchers in the UK," said Choiniere, a recent emigrant from the United States to South Africa. "Dinosaurs have not observed international borders and it is important that our research groups not either."

Explore more:
Giant dinosaur bones encourage paleontologists to rethink the triassic period

More information:
Current Biology (2018). www.cell.com/current-biology/f … 0960-9822 (18) 30993-X