Scientists unearth Africa's oldest dinosaur

A team of scientists in northern Zimbabwe say they have found the remains of an ancient sauropodomorph — a long-necked dinosaur — that roamed the earth around 230 million years ago.

The discovery of the newly named Mbiresaurus raathi, one of the world's oldest dinosaurs, in that part of Africa would support the idea that dinosaurs were initially confined to a particular climactic belt of a single supercontinent.

What do we know about Mbiresaurus raathi?

According to the team's findings published in the journal Nature, Mbiresaurus stood on two legs and had a relatively small head like its dinosaur relatives. It also had small, serrated, triangle-shaped teeth, suggesting that it was an herbivore or potentially omnivore.

As a sauropodomorph, Mbiresaurus is part of the lineage that gave rise to the sauropod dinosaurs, a group that includes the diplodocus and the brontosaurus.

The animal is estimated to have been about 6 feet long (1.82 meters) with a long tail and weighed anywhere from 20 to 65 pounds (9 to 30 kilograms).

The skeleton — incredibly, mostly intact — was missing only some of the hand and portions of the skull. It was first found by a graduate student at US institution Virginia Tech, Chris Griffin, and other paleontologists over two digs in 2017 and 2019.

What might the discovery show?

The find could help explain the migration and distribution of early dinosaurs at a time when present-day continents were connected and made up one supercontinent — Pangea.

At that time, the theory is that latitude and climate controlled the distribution of such dinosaur species, rather than continental divides that emerged later as the continents broke apart. 

For that to be true, scientists would expect the sort of skeletons — previously found in deposits in South America and India — to be also found in south-central Africa. At that time, all three parts of the world were packed together at the same latitude on Pangea.

Griffin, now a post-doctorate researcher at Yale University, and his team had purposefully targeted northern Zimbabwe as the country fell along this same climate belt as southern Brazil and India during the Late Triassic Age — when the animals would have lived.

"These are Africa's oldest-known definitive dinosaurs, roughly equivalent in age to the oldest dinosaurs found anywhere in the world," Griffin explained.

The climate across Pangea is thought to have been divided into strong humid and arid latitudinal belts, with dinosaurs thriving where it was more humid.

"Because dinosaurs initially dispersed under this climatic pattern, the early dispersal of dinosaurs should therefore have been controlled by latitude," Griffin said. "The oldest dinosaurs are known from roughly the same ancient latitudes along the southern temperate climate belt what was at the time, approximately 50 degrees south."

The finds together would appear to show that the oldest dinosaurs thrived and were constrained to those areas before going on to spread across the globe and form new species.

The team, describing a two-pronged approach to back their theory, also used data to show that a northward dispersal of dinosaurs came with increased global humidity that broke down climate barriers and allowed them to spread.

Edited by: Natalie Muller