Zimbabwe's Triassic dinosaurs reveal distinct evolutionary path from South Africa

Africa holds roughly a quarter of all animal and plant species alive today, a richness born from its varied terrain—deserts that stretch to the horizon, grasslands that roll without end, forests so dense they swallow light, mountains that pierce the sky, coastlines where land meets sea. But this abundance has deeper roots. Many of the animal and plant groups we know today first evolved here, in Africa's distant past, and paleontologists have been digging into that history for nearly two centuries.

When people think of African fossils, they usually think of hominids—the bones that tell us who we are and where we came from. But Africa's fossil record holds far more. Dinosaurs walked these lands, and their remains have turned up in South Africa, Lesotho, Tanzania, Egypt, Niger, Malawi, Madagascar, and Morocco. The first scientifically documented African dinosaur fossils came from the Eastern Cape in South Africa in the 1850s. Zimbabwe, though, has been part of this paleontological puzzle since 1916, when dinosaur bones were first reported there. For decades, those finds remained largely overlooked by the wider scientific community.

It wasn't until the 1970s that Zimbabwean dinosaurs began to receive serious attention, thanks to Geoffrey Bond and Michael Raath, two paleontologists working in the country. They uncovered abundant material in the hinterlands around Bulawayo, in the southwest, and in the lower Zambezi Valley, which forms the border with Zambia. Most of what they found was initially classified as belonging to species already known from South Africa. Then paleontological work in Zimbabwe slowed. But a handful of dedicated fossil hunters kept searching. One of them, Steve Edwards, a manager at a local safari camp, discovered new and productive sites along the shore of Lake Kariba, the massive artificial lake that marks most of the border between Zimbabwe and Zambia.

When word of these discoveries reached Jonah Choiniere, a specialist in early dinosaurs at the University of the Witwatersrand in Johannesburg, he recognized immediately that the material was significant. He assembled an international team from South Africa, Zimbabwe, and the United Kingdom to investigate further. The challenge was logistical: the Lake Kariba sites lie deep within Matusadona National Park, remote and difficult to access. The solution was ingenious—the team used one of the Kariba houseboats as both a mobile hotel and a field laboratory, allowing them to prospect the shoreline systematically. Two expeditions, in 2017 and 2018, yielded a trove of fossils from brick-red mudstones and sandstones deposited by ancient rivers around 210 million years ago, during the Late Triassic period.

The rocks tell a story of the landscape those dinosaurs inhabited. Geological evidence and plant fossils show that the Triassic world of Kariba was dry, studded with stands of large conifer trees, with ribbons of green vegetation following permanent watercourses. Among the fossils recovered was Musango matusadonaensis, a sauropodomorph dinosaur—a member of the group that would eventually evolve into the four-legged, long-necked giants like Diplodocus. Musango's incomplete skeleton revealed an animal that walked on its hind legs alone, measured about 4.5 meters in length, and weighed around 220 kilograms. Growth marks in its bones showed it was still a subadult when it died. The skull did not survive, so its diet remains uncertain, though its close relatives were mostly herbivorous.

What emerged from this work was unexpected. The Zimbabwean dinosaurs were not simply variations on the South African fauna, as scientists had assumed. Instead, they represented an array of species found nowhere else. Musango and another sauropodomorph called Musankwa, described in 2024 from the same beds, are unique to Zimbabwe. The team had expected to find South African dinosaur species in these rocks, given their similar age and geographic proximity. Instead, every specimen collected so far has proven distinct from animals found elsewhere. The Zimbabwean dinosaurs are not even the closest relatives of their South African neighbors. The fossil record also includes other animals—lungfish and aquatic reptiles called phytosaurs—that are rare or absent in South African sites. When paleontologists reexamined historical collections from Bulawayo, many of those fossils too proved impossible to assign to South African species, contradicting earlier assumptions.

The explanation likely lies in geography and climate. During the Triassic, Zimbabwe sat farther north than South Africa and closer to the equator, meaning it experienced different climatic conditions. Climate is known to exert a powerful influence on which animals live where, and these differences may have shaped the distinct communities of dinosaurs that evolved in each region. To test this hypothesis and learn more, the team plans to return to Kariba to search for additional fossils and to gather more precise information about the ages and environments of the dinosaur-bearing rocks, allowing for more detailed comparisons with sites elsewhere in Africa. Zimbabwe's role in illuminating the early stages of dinosaur evolution is only now becoming clear.