An early relative of Diplodocus that walked on two legs has been found near one of the world’s largest artificial lakes.
Discovered on the shore of Lake Kariba in Zimbabwe, Musango matusadonaensis is a rare find in a country with a relatively unknown palaeontological past. Only four other dinosaur species have been named from the region, leaving key questions about Zimbabwe’s past unanswered.
The discovery of Musango goes some way towards changing this. The 4.5-metre-long sauropodomorph dinosaur was found in the same rocks as the larger Musankwa sanyatiensis, showing that ecosystems capable of supporting a variety of dinosaurs existed around 210 million years ago in the Late Triassic.
This was an important time in the evolution of life, as dinosaurs were beginning to spread around the planet as they moved towards becoming Earth’s dominant animals. Professor Paul Barrett, the study’s lead author, says that further discoveries from the region are likely to transform our understanding of this crucial time.
“Until recently, it was assumed that the dinosaurs living across southern Africa were largely the same,” he explains. “However, these discoveries are showing that this part of the ancient supercontinent Gondwana was actually made of a series of smaller ecosystems – each with a different cast of characters.”
“It suggests that what we’ve found so far is only the tip of the iceberg. We’ve already got one other new species that we’ve yet to describe, while our team has been told about other fossils from the region that we’re yet to look at. I think it’s likely there are even more dinosaurs still to be found there.”
Professor Jonah Choiniere from Johannesburg’s Evolutionary Studies Institute (ESI), adds that the discovery “reinforces the importance of southern Africa in understanding dinosaur diversity”.
“This study is the result of a thriving international collaboration between the UK, South Africa and Zimbabwe. New dinosaur species like Musango show the value of doing palaeontological fieldwork in remote, and often scenically beautiful, places.”
The findings of the study were published in the Journal of Systematic Palaeontology.
How was the dinosaur Musango discovered?
The discovery of Musango was a little out of the ordinary. Rather than searching for dinosaur bones in arid deserts or mountains, the team searched the area around Lake Kariba, on the border of Zimbabwe and Zambia, which is rich in water and wildlife of all kinds.
As the lake is in one of Zimbabwe’s national parks, the team of Zimbabwean, South African and British palaeontologists had to do things a bit differently. Rather than hiking into the wilderness, or driving in a jeep, their expeditions in 2017 and 2018 were conducted from a boat.
“It’s one of the most exciting digs I’ve been on,” recalls Paul. “Being on a boat kept us mobile as we searched the area, but also kept us safe from the elephants, crocodiles and hippos that live nearby!”
“It was nice to be involved in research that was purely exploratory, as we had no idea what we might find. This was about filling a blank spot on the palaeontological map of southern Africa and discovering what was within that.”
Among the many fossils uncovered by the team was Musango matusadonaensis. Musango is a word from the ChiShona language meaning ‘living in the bush’, in reference to the remote area it was found in, while the name of the species comes from the name of the Matusadona National Park nearby.
The dinosaur’s fossils were spotted jutting out from rocks just a few metres above the water before the team returned to excavate the surrounding area. Their finds were prepared at the ESI, where they were studied by the team before being returned to the Natural History Museum of Zimbabwe.
What do we know about Musango’s life?
A variety of bones from across Musango’s skeleton have been discovered, including parts of the spine, ribs, arms, legs and feet. Analysis of the animal’s bones suggests that it was around eight years old and almost fully grown at the time of its death and had previously recovered from a serious infection or injury.
“For a dinosaur from this time, we actually have quite a lot of Musango,” Paul adds. “Unfortunately, this doesn’t include the skull. It’s likely to have been either a herbivore or omnivore based on its relatives, but we can’t be certain without being able to look at its head.”
Taken together, the fossils add up to a dinosaur that’s estimated to have been around 4.5 metres long. While this is about the length of a car, Musango would have been much lighter at 222 kilogrammes in weight.
Understanding southern Africa in the Late Triassic
The discovery of Musango and other fossils in the region is building up a picture of what Late Triassic Zimbabwe would have been like. Rather than the drier areas found in what are now South Africa and Lesotho, Zimbabwe gives more evidence for animals living in and around the rivers of Gondwana.
“We find the fossils of freshwater animals such as lungfish and the crocodile-like phytosaurs in Zimbabwe, suggesting there were more permanent bodies of water here than in similarly aged areas elsewhere in southern Africa,” says Paul.
“This ecosystem was able to support both Musankwa and Musango, and likely other undiscovered dinosaurs as well. While Musankwa and Musango would have been a similar size when they were younger, it seems reasonable to assume they were browsing at different heights and eating different things as adults so that they could co-exist.”
In fact, the links between these dinosaurs go much deeper. Analysis of their fossils in a family tree shows that both species are each other’s closest relatives. They’re both part of a small group of dinosaurs known as Unaysauridae which lived across Africa, India and South America when they were all parts of Gondwana.
Understanding how this group of early dinosaurs, and others, moved from being a relatively small part of life in the Triassic to a major part of the Jurassic and Cretaceous ecosystems that followed is still a major area of research. However, Paul believes that under-studied areas like Zimbabwe may hold important clues to answer this question.
“We know that areas of Europe and North America have been far better studied than many other regions of the world, leaving gaps in the fossil record,” Paul explains. “Expeditions to lesser-known areas are important to change this and give us a broader view of what was happening at the time.”
“It’s also important to revisit sites that haven’t been touched for decades. Zimbabwe’s Early Jurassic rocks, for example, haven’t been studied in depth for around 50 years, so a reanalysis would help to bring our knowledge of these areas up to date.”
