Researchers have identified a 240-million-year-old prehistoric animal species in London’s Natural History Museum collections as Dinodontosaurus isiyavamanda. Discovered in Tanzania, the herbivore links East African rocks to South American deposits, prompting a reassessment of early dinosaur evolution and when the earliest dinosaur candidates first emerged.
A 60-Year-Old Museum Specimen Gets a New Identity
An extensive collection of synapsid fossils—mammal-lineage vertebrates that flourished before dinosaurs—was unearthed during a British expedition in 1963 to what is now Tanzania. Brought back to the Natural History Museum in London, the specimens sat largely unstudied for decades, leaving significant gaps in our understanding of ecosystems approximately 240 million years ago during the Triassic period.
Researchers recently returned to an undescribed associated dicynodont skeleton from that historic collection, examining it alongside a more recently discovered fragmentary skull. To the surprise of the scientific team, the bones belonged to the genus Dinodontosaurus, a herbivore previously known exclusively from South America.
Further anatomical analysis confirmed that the Tanzanian material represents a distinct, previously unknown species. The team named the animal Dinodontosaurus isiyavamanda, honoring the land of the Wamanda people who inhabit the region where the original fossils were collected.
Decades in the Making: From an MSc Thesis to Advanced Micro-CT Scanning
The formal description of the species, published in the Journal of Vertebrate Palaeontology, marks the culmination of a scientific journey spanning nearly thirty years.
Larkin noted that modern technology transformed the research process. Advanced imaging techniques like micro-CT scanning allowed the team to examine specimens in greater detail than was possible in the 1990s, while global cooperation streamlined collaboration across institutions.
Reshaping the Timeline of Early Dinosaur Evolution
Beyond naming a new animal, the discovery carries implications for prehistoric geology. The Tanzanian rock beds yielding Dinodontosaurus isiyavamanda are the same geological deposits that have produced fossils proposed as some of the earliest possible dinosaurs.
Previously, scientists linked these East African rock sequences to formations in South Africa, treating them as Middle Triassic equivalents. However, because Dinodontosaurus is now confirmed in both Tanzania and South America, it builds a direct geological link between the two regions.
Recent radiometric dating from South America indicates that those linked rock sequences are up to 10 million years younger than previously dated South African deposits. This chronological shift provides evidence that the Triassic rocks of Tanzania may not preserve the oldest potential dinosaur fossils after all, forcing paleontologists to re-evaluate when and where dinosaurs first emerged.
Next Steps for Triassic Ecosystem Research
The identification of Dinodontosaurus isiyavamanda opens up fresh avenues of study. A significant amount of Tanzanian dinodontosaurus material remains unexamined, particularly the postcranial skeleton.
Upcoming research projects will analyze the remaining fossils, contrast the East African remains directly with South American specimens, and model the biomechanics and ecology of Triassic dicynodonts. These efforts aim to clarify how several large herbivorous animals managed to coexist during the period when dinosaurs were beginning to emerge.