Tanzanian Fossil Reveals 240-Million-Year-Old Species and Reshapes Dinosaur Origins

A prehistoric animal that lived roughly 240 million years ago in what is now Tanzania has been formally identified as a species new to science, and its recognition is sending ripples through one of palaeontology’s most contested debates: when and where the first dinosaurs evolved. An international team led by the University of Bristol has described the creature, named Dinodontosaurus isiyavamanda, in the Journal of Vertebrate Palaeontology. The animal belonged to the dicynodonts, a successful group of herbivorous synapsids—vertebrates on the lineage that eventually led to mammals—that flourished across the Triassic world long before dinosaurs rose to dominance. Although dicynodonts left no living descendants, their fossils serve as crucial time markers, and the presence of this particular genus in Tanzania carries unexpected consequences for the age of rocks that have been claimed to contain the oldest known dinosaur fossils on Earth.

The story of the discovery begins more than six decades ago. In 1963, a British expedition collected an extensive suite of synapsid fossils from Triassic deposits in what is now Tanzania. The material was eventually housed at the Natural History Museum in London, where it remained only partly studied for generations. Because many of the specimens had never been formally described, palaeontologists could not be certain what animals they represented or what they revealed about the ecosystems of the Middle Triassic, a pivotal interval in the history of life on land. Among the unstudied material was an associated skeleton belonging to a large herbivorous dicynodont, alongside a more recently discovered fragmentary skull from the same region. It was these specimens that the new research set out to resolve.

Detailed anatomical work on the skeleton and skull produced a surprise. The fossils did not belong to a local Tanzanian genus, as might have been expected, but to Dinodontosaurus, a dicynodont previously known only from South America. Further comparative study confirmed that the Tanzanian material differed from its South American relatives in ways sufficient to warrant designation as a distinct species, which the team named Dinodontosaurus isiyavamanda. The species name honours the Wamanda people, who inhabit the region of Tanzania where the fossils were found, anchoring the animal’s scientific identity to the landscape and communities connected to its discovery.

The implications of this biogeographic link extend far beyond taxonomy. The Tanzanian rocks that yielded Dinodontosaurus isiyavamanda belong to the same geological deposits that have produced fossils thought by some researchers to represent the oldest possible dinosaurs. For decades, these rocks were believed to share certain fossil genera with contemporaneous-looking sequences in South Africa, which were assigned a Middle Triassic age. If the Tanzanian deposits were equivalent to those South African beds, then any dinosaur-like fossils within them could plausibly rank among the earliest of their kind. The recognition of Dinodontosaurus in both Tanzania and South America now provides a direct correlation between the rock sequences of those two regions, indicating that they accumulated during the same span of geological time.

That correlation matters because of what recent dating work has revealed on the other side of the Atlantic. New radiometric dates from South America suggest that the early dinosaur-bearing rock sequences there are up to 10 million years younger than the comparable sequences in South Africa. Because the Tanzanian beds can now be tied to the South American sequences through their shared Dinodontosaurus faunas, the conclusion follows that the Triassic rocks of Tanzania can no longer be regarded as preserving the oldest potential dinosaur fossils. Instead, the dinosaur candidates from Tanzania are probably no older than those from South America, a shift that forces a reassessment of the timing and geography of dinosaur origins.

Hady George, a PhD student in the School of Earth Sciences at the University of Bristol and lead author of the study, emphasised the significance of the finding. He noted that the discovery marks the first confirmed record of the genus Dinodontosaurus outside South America, and that the finding links the Tanzanian and South American fossil-bearing rocks, showing that they are of equivalent age. According to George, this helps confirm that the oldest dinosaur candidates from Tanzania are probably no older than those from South America, refining the timeline of dinosaur origins. He added that forthcoming research projects will examine the remaining fossil material and explore the biomechanics and ecology of Triassic dicynodonts, work that promises to illuminate how these remarkable herbivores lived and interacted.

The new species also carries a deeply personal story of scientific patience. Nigel Larkin, a palaeontologist and Visiting Research Fellow in the School of Biological Sciences at the University of Reading and a co-author of the paper, first studied the dicynodont skeleton for his master’s thesis at University College London in 1994. Even then, he judged it to represent a species new to science, but the formal write-up languished for nearly 30 years. Larkin reflected that he was glad to have waited, because the international team assembled under George’s leadership was able to develop the story in far greater detail and depth than he could have achieved alone. He observed that techniques have improved vastly over the past three decades, allowing researchers to extract far more information from specimens using methods such as micro-CT scanning than could have been imagined in the 1990s, and that international collaboration has become far easier. As he put it, what is 30 years compared with the age of a prehistoric specimen?

The fossils themselves have spent most of their modern history in museum storage. Dr Mike Day, Curator of Non-Mammalian Tetrapods at the Natural History Museum in London, explained that the Tanzanian specimen has been in the museum’s care for over 60 years, and that its identity has now finally been brought to light. He noted that revealing Dinodontosaurus lived in both South America and eastern Africa offers a glimpse of the planet 240 million years ago, and that the discovery demonstrates how revisiting museum collections can change our understanding of the past just as much as finding new fossils in the field. His remarks underscore a growing theme in modern palaeontology: historic collections, properly curated and re-examined with contemporary methods, remain invaluable records of life on Earth and continue to yield discoveries decades after excavation.

Technically, the study rests on careful craniomandibular osteology—the detailed description of the skull and lower jaw bones—of the new species, which the authors formally diagnose as Dinodontosaurus isiyavamanda sp. nov. within the therapsid group Anomodontia. Dicynodonts are characterised by their turtle-like beaks and, in many species, tusks, and they dominated terrestrial herbivore niches through much of the Permian and Triassic periods. Because different dicynodont genera appear, vanish, and evolve at different points in the Triassic, their presence in a rock unit functions much like a fingerprint in time. Establishing that the Tanzanian Manda Beds contain the same genus as dated South American sequences therefore provides a biostratigraphic anchor that radiometric dating from South America can calibrate, tightening the chronological framework for the entire region and for the critical interval when dinosaurs first appear in the fossil record.

The discovery also opens a substantial research agenda. A large amount of the Tanzanian Dinodontosaurus material remains to be examined, particularly the postcranial skeleton—the bones beyond the skull and jaws—which has yet to receive the same level of anatomical scrutiny. Future work will investigate the anatomy of these remains and compare them directly with South American specimens, testing how the two populations relate and what their differences reveal about evolution across a vast landmass. The researchers also plan to study the biomechanics of Dinodontosaurus and related dicynodonts to better understand how multiple large herbivorous species managed to coexist in Triassic ecosystems, a question with parallels to the dynamics of modern megaherbivore communities. For now, the humble museum drawer in London has delivered a result with outsized consequences: a new species, a transcontinental correlation, and a younger, more precise window onto the dawn of the dinosaurs.

Subject of Research: A new Triassic dicynodont species from Tanzania and its implications for the age of early dinosaur-bearing rocks

Article Title: New species of 240-million-year-old prehistoric animal from Tanzania discovered

Article References: New species of 240-million-year-old prehistoric animal from Tanzania discovered. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Dinodontosaurus isiyavamanda, dicynodonts, Triassic, Tanzania, dinosaur origins, synapsids, Natural History Museum London, University of Bristol, biostratigraphy, radiometric dating, museum collections, Journal of Vertebrate Paleontology