Oldest dinosaur fossil in Africa discovered

Finding ‘Mbiresaurus raathi’ also helps scientists develop new theory of dinosaur migration

Paleontologists have discovered and named the oldest dinosaur skeleton found yet in Africa in northern Zimbabwe.

The long-necked dinosaur, newly named Mbiresaurus raathi, was unearthed first over the course of two digs, in 2017 and 2019, said scientists, including those from Virginia Tech in the US.

Mbiresaurus raathi was likely about 6ft (1.8m) tall with a big tail, weighing anywhere from 20-65lb (9-30kg), and was a predecessor of the long-necked sauropods, according to the study, published on Wednesday in the journal Nature.

These are Africa’s oldest-known definitive dinosaurs, dating back to about 230 million years ago and similar in age to the oldest ones found in other parts of the world, according to researchers.

“The oldest known dinosaurs – from roughly 230 million years ago, the Carnian Stage of the Late Triassic period – are extremely rare and have been recovered from only a few places worldwide, mainly northern Argentina, southern Brazil, and India,” said study co-author Christopher Griffin, who graduated in 2020 with a PhD in geosciences from Virginia Tech.

“The discovery of Mbiresaurus raathi fills in a critical geographic gap in the fossil record of the oldest dinosaurs and shows the power of hypothesis-driven fieldwork for testing predictions about the ancient past,” Dr Griffin said.

Based on fossil findings, researchers said Mbiresaurus may have stood on two legs and had a relatively small head like its dinosaur relatives.

They suspect it was an herbivore or potentially omnivore due to its small, serrated, triangle-shaped teeth.

“Early dinosaurs like Mbiresaurus raathi show that the early evolution of dinosaurs is still being written with each new find and the rise of dinosaurs was far more complicated than previously predicted,” said Sterling Nesbitt, associate professor of geosciences and another author on the study.

“When I found the femur of Mbiresaurus, I immediately recognised it as belonging to a dinosaur and I knew I was holding the oldest dinosaur ever found in Africa. When I kept digging and found the left hip bone right next to the left thigh bone, I had to stop and take a breath,” Dr Griffin said.

The new discovery has also helped scientists develop a new theory of dinosaur migration.

During this time, 230 million years ago, Zimbabwe was further south than it is today, and was part of the massive supercontinent Pangaea.

The climate of this supercontinent at the time was divided into strong humid and arid latitudinal belts and more temperate belts spanning higher latitudes and intense deserts across the lower tropics, researchers said.

“Because dinosaurs initially dispersed under this climatic pattern, the early dispersal of dinosaurs should therefore have been controlled by latitude,” Dr 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,” he added.

Scientists suspect the earliest dinosaurs were restricted by climatic bands to southern Pangea initially and only later dispersed worldwide.

They said climatic controls influenced the initial composition of terrestrial dinosaurs and other major groups such as mammals, turtles, amphibians and reptiles on the continent, many of which persist even today.