Ledumahadi mafube: New 26,000-Pound Dinosaur Discovery Was Earth's Largest Land Animal
Named Ledumahadi mafube, the new dinosaur species weighed 12 tons, stood about 13 feet (4 m) high at the hips, and is one of the closest relatives of sauropod dinosaurs.
Ledumahadi mafube evolved its giant size independently from sauropods.
“It shows us that even as far back as 200 million years ago, these animals had already become the largest vertebrates to ever walk the Earth,” said Professor Jonah Choiniere, a researcher in the Evolutionary Studies Institute at the University of the Witwatersrand.
“Many giant dinosaurs walked on four legs but had ancestors that walked on two legs,” said Professor Roger Benson, a scientist in the Department of Earth Sciences at the University of Oxford and the Evolutionary Studies Institute at the University of the Witwatersrand.
“Paleontologists want to know about this evolutionary change, but amazingly, no-one came up with a simple method to tell how each dinosaur walked, until now.”
To determine whether Ledumahadi mafube walked on two legs, like its ancestors, or on four, the researchers developed a method using measurements of today’s animals.
The method involved taking measurements of the thickness of dinosaur’s limbs to infer their weight and how many limbs that weight must have been carried on.
The team’s findings suggest not only that this dinosaur was a quadruped, but also that many other early sauropodomorph dinosaurs (often called ‘prosauropods’) were experimenting with walking on all fours.
“The discovery shows that gigantic body sizes were possible in early four-legged prosauropods, which arose from earlier two-legged species,” the paleontologists said.
“However, the early quadrupeds lacked the columnar, elephant-like limb postures of later sauropod species such as Brontosaurus.”
“The evolution of sauropods isn’t quite as straightforward as we once thought,” Professor Choiniere said.
“In fact, it appears that sauropodomorphs evolved four-legged postures at least twice before they gained the ability to walk with upright limbs, which undoubtedly helped make them so successful in an evolutionary sense.”
“More broadly, the findings show that millions of years before Tyrannosaurus or Velociraptor came on the scene in the northern hemisphere, there was a thriving dinosaur ecosystem here in South Africa, at the bottom of the world, featuring 12 ton giants like Ledumahadi mafube, tiny carnivores like Megapnosaurus, the earliest mammals, some of the earliest turtles, and many, many others,” he said.
“Africa, and particularly South Africa, is known for its big game. I think we should be just as famous for our big game of the early Mesozoic, 200 million years ago.”
The findings appear in the journal Current Biology.
Blair W. McPhee et al. A Giant Dinosaur from the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs. Current Biology, published online September 27, 2018; doi: 10.1016/j.cub.2018.07.063