Tanzanian Fossil Extends Dinosaur Ancestry by 20 Million Years

A multinational group of paleontologists reported uncovering a new prehistoric creature in Tanzania that inhabited Earth about 240 million years ago, in the Middle Triassic. Detailed in a newly published scientific paper, the specimen introduces a fresh species to the fossil record and may push back the date for the appearance of the earliest true dinosaurs.

The animal, dubbed Dinodontosaurus isiyavamanda, was recovered from sedimentary deposits of the Ruhuhu Basin—a locality already noted for early archosaur fossils. Radiometric dating together with stratigraphic work assign the specimen to the Ladinian stage of the Triassic, roughly 20 million years older than the oldest confirmed dinosaurs.

Scientists note that Dinodontosaurus’s anatomy fills a morphological void between basal archosaurs and later dinosauriforms. The skull and teeth combine primitive elements with derived traits typical of early dinosaur evolution, implying that the divergence of dinosaur ancestors from their relatives may have taken place sooner than formerly assumed.

During the Triassic, reptile lineages diversified swiftly, with archosaurs splitting into multiple clades that would later dominate the Mesozoic era. Before this find, experts generally dated the rise of true dinosaurs to the late Triassic, about 230 million years ago. This new specimen offers tangible proof that the evolutionary experiment giving rise to dinosaurs was already in progress in the middle of the Triassic.

Researchers from the University of Bristol headed the investigation, collaborating with partners from Tanzania, Germany and the United States. By employing high‑resolution CT scans, the team digitally rebuilt the fossil’s skeletal structure while preserving the fragile bones. Comparative work with other Triassic taxa clarified the creature’s phylogenetic placement and bolstered the case for recognizing a new species.

Although this discovery does not overturn the whole story of dinosaur origins, it highlights the value of poorly studied African fossil localities. The authors expect that continued excavation in the Ruhuhu Basin may uncover more specimens that shed light on the initial phases of dinosaur evolution. As additional evidence surfaces, scientists will revisit models of archosaur diversification and the environmental drivers behind the dinosaurs’ ascent.