Photograph of the outcrop at locality Z143 where NMT RB462 was collected
Photograph: K. Angielczyk.
George, H., et al. (2026) (CC-BY 4.0)
George, H., et al. (2026) (CC-BY 4.0)
Scientists have revised their understanding of some fossils once thought to include the oldest dinosaurs. Scientists getting it wrong and having to change their minds should be music to creationist ears — until they discover what the revision actually means. The animals concerned still lived hundreds of millions of years before the supposed ‘Creation Week’ of biblical literalism. A reassessment within the Triassic does nothing to squeeze the history of life into a few thousand years.
Creationists have an almost schizophrenic attitude towards science: On the one hand they claim scientists are not allowed to publish anything which doesn't conform to some assumed scientific orthodoxy; on the other hand they point to scientific disagreement and debate and scientists even changing their mind as evidence that science is unreliable. And they readily use a computer to inform the world via the Internet that science doesn't work, without the slightest appreciation of the irony!
The research, led by Hady George of the University of Bristol and published in the Journal of Vertebrate Paleontology, describes a new species of dicynodont from Tanzania: Dinodontosaurus isiyavamanda. Despite its name, this herbivore was a member of the mammalian evolutionary lineage, rather than a dinosaur. This discovery extends a genus previously known only from South America into Africa, around 240 million years ago.
Notice what is happening here. Scientists are testing an earlier interpretation against additional evidence and publishing the reasons for changing it. The revision concerns how particular fossil assemblages fit into an established geological history. It supplies no evidence for a recent creation, and no reason to replace that history with Genesis.
There is also a revealing human story behind the discovery. In his account of the research, George openly describes mistakes in his initial anatomical interpretations and how colleagues helped him correct them. Further comparisons eventually supported the identification of a new species within an existing genus. Here is scientific self-correction taking place through scrutiny, collaboration and a willingness to abandon an interpretation when the evidence no longer supports it.
For creationists hoping to turn “scientists have changed their minds” into “therefore the Bible was right”, the difficulty should be obvious. Showing that one scientific interpretation needs revision does not establish an unrelated religious claim. That claim still needs evidence of its own. Meanwhile, even the proposed adjustment spans vastly more time than young-Earth creationism allows for the entire existence of the Universe.
How do scientists date a fossil when they cannot date the fossil itself? A fossil rarely comes with a directly measurable date of death. For ancient, mineralised bones, scientists usually establish an age by investigating the rocks containing them and comparing several kinds of evidence. Understanding this process explains why an age estimate can change without undermining the methods used to reconstruct geological history.The paper in the Journal of Vertebrate Paleontology was announced in a University of Bristol’s news release:
Glossary
- Putting events in order
In a sedimentary sequence that has not been overturned, lower layers were deposited before those above them. This principle allows geologists to establish a relative chronology: which deposits came first and which came later. They also investigate folding, faulting, erosion and gaps in deposition, rather than assuming that every sequence is complete and undisturbed.
Relative dating establishes an order of events; it does not, by itself, tell us how many years separate them. Numerical dates provide that additional information. The US National Park Service’s guide to geological time explains this distinction.
- Using fossils to connect different places
Different intervals of geological history contain different combinations of organisms. By comparing these fossil assemblages, researchers can correlate rock sequences across considerable distances. This approach is called biostratigraphy.
However, finding the same genus in two deposits does not establish that they formed at precisely the same time. A genus may have existed for millions of years, and organisms can spread into different regions at different times. Comparisons involving several groups, supported by other geological evidence, generally provide stronger constraints than a single shared fossil.
- Adding numerical ages
Radiometric dating uses the predictable decay of radioactive isotopes to measure elapsed time. Where suitable volcanic layers occur within a sedimentary sequence, their minerals can provide numerical dates that constrain the age of nearby fossils.
For example, imagine a fossil-bearing bed lying between two undisturbed layers of volcanic ash, deposited during eruptions dated to 242 and 238 million years ago. Assuming the fossils have not been eroded from older rocks and redeposited, their age would fall between those dates. These figures are an illustration, not measurements from the Tanzanian study.
The material dated, its geological context and the method used all matter. Researchers must check whether a mineral records the event of interest and whether later processes have disturbed it. Different techniques suit different materials and age ranges, as outlined in the Smithsonian’s guide to dating. Carbon dating, for example, cannot date Triassic fossils: its useful range extends only tens of thousands of years into the past.
- Why an estimated age can change
A deposit without a suitable direct radiometric date may initially be assigned an age through comparison with another fossil-bearing sequence. A mistaken fossil identification, an incomplete understanding of a group’s geographical distribution, or new dates from the comparison site can require that correlation to be revised.
This is an inference being tested against additional evidence. It does not automatically mean that a radiometric measurement was wrong.
- What changed in Tanzania?
According to the University of Bristol’s account, identifying Dinodontosaurus isiyavamanda provides a new connection between Tanzania’s fossil-bearing deposits and those of South America. Radiometric dates from the South American sequences support a younger age than the traditional comparison with South African rocks suggested.
This adds evidence that the Tanzanian deposits may not preserve the oldest potential dinosaurs after all. The revision concerns their position within Triassic history, on a scale of millions of years. It supplies no support for reducing that history to the few thousand years required by young-Earth creationism.
- Stratigraphy
- The study of rock layers, their sequence and their relationships.
- Biostratigraphy
- The use of fossils to correlate and assign relative ages to rock layers.
- Fossil assemblage
- The collection of fossil organisms represented in a particular deposit or interval.
- Correlation
- Establishing a relationship between rock sequences in different locations, including their probable equivalence in age.
- Radiometric dating
- Determining an age from measurements of radioactive isotopes and their decay products.
- Reworking
- The erosion of older material, such as a fossil, followed by its incorporation into a younger deposit.
New species of 240-million-year-old prehistoric animal from Tanzania discovered
A new prehistoric animal species from Tanzania dating back around 240 million years to the Triassic period has been described by an international team of researchers. Led by the University of Bristol, the new species, named Dinodontosaurus isiyavamanda, could help scientists refine the age of one of the world’s most significant fossil sites, and reshape the timeline of early dinosaur evolution.
The study, published in the Journal of Vertebrate Palaeontology today [16 September], suggests that some of the earliest potential dinosaur fossils from Tanzania may be younger than previously thought.
More than 60 years ago, an extensive collection of synapsid fossils - mammal-lineage vertebrates that flourished before the rise of dinosaurs - was discovered during a British expedition in 1963 to what is now Tanzania. These fossils were housed at the Natural History Museum, London, but were only partly studied, leaving uncertainty over the identity of some of the fossils and what they could reveal about ecosystems approximately 240 million years ago.
By examining one of the undescribed associated skeletons belonging to a herbivorous group of synapsids called dicynodonts, together with a more recently discovered fragmentary skull, the research team found that the fossils belong to the genus Dinodontosaurus. The discovery was unexpected, as Dinodontosaurus had previously been known only from South America.
Further anatomical study confirmed that the Tanzanian material represents a previously unknown species, which the researchers have named Dinodontosaurus isiyavamanda. The name is a reference to the land of the Wamanda people, who inhabit the region of Tanzania where the fossils were found. The discovery has important implications beyond the identification of a new species.
The Tanzanian rocks that yielded Dinodontosaurus isiyavamanda are the same geological deposits that have produced fossils thought to represent the oldest possible dinosaurs. These rocks were previously thought to share some fossil genera with rocks in South Africa, which were thought to be Middle Triassic.
As Dinodontosaurus is now known to exist in both Tanzania and South America, it provides a new link between rock sequences in both countries and indicates that they are of equivalent age.
New radiometric dates from South America suggest that these early dinosaur-bearing rock sequences are up to 10 million years younger than that of South Africa.
This adds further evidence that the Triassic rocks of Tanzania can no longer be regarded as preserving the oldest potential dinosaur fossils*, prompting a reassessment of when and where dinosaurs first evolved.
Our discovery marks the first confirmed record of the genus Dinodontosaurus outside South America. The finding links the Tanzanian and South American fossil-bearing rocks, showing they are of equivalent age. 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. Forthcoming research projects will examine the remaining fossil material and explore the biomechanics and ecology of Triassic dicynodonts.
Hady George, lead author.
Palaeobiology Research Group
School of Earth Sciences
University of Bristol
Bristol, UK.
I studied this dicynodont skeleton for my MSc thesis at University College London back in 1994 and judged it to be a species new to science, but it took me nearly 30 years to start the process of writing it up for publication. I’m glad I waited, as the international team we put together, headed by Hady George, has done an amazing job of fleshing-out this story in much more detail and depth than I could have achieved on my own. Techniques have improved vastly over the last 30 years too – we can do so much more with Micro CT scanning etc to examine such specimens than we ever could have imagined in the 1990s, and international collaboration is so much easier. And what’s 30 years? It’s the blink of an eye compared to the age of this prehistoric specimen.
Nigel R. Larkin, co-author
School of Biological Sciences
University of Reading,
Reading, U.K.
This fossil specimen from Tanzania has been in our care for over 60 years, and it’s wonderful that its identity has now been brought to light. By revealing that Dinodontosaurus lived in South America and eastern Africa, it offers a glimpse of our planet 240 million years ago. It goes to show how revisiting museum collections can change our understanding of the past just as much as finding new fossils in the field, showing the importance of looking after these invaluable records of life on Earth.
Dr Michael O. Day, Co-author
Section of Fossil Reptiles, Amphibians, and Birds
Natural History Museum
London, U.K.
The new discovery opens the door to further research. A large amount of the Tanzanian Dinodontosaurus material remains to be examined, particularly the postcranial skeleton.
Future work will investigate the anatomy of these remains and compare them with South American specimens. The researchers also plan to study the biomechanics of Dinodontosaurus and related dicynodonts to better understand how multiple large herbivorous species were able to coexist in Triassic ecosystems.
Publication:
For creationists, the temptation is to seize on the revision and announce that scientists have been wrong again. But the relevant question is: wrong about what? Reconsidering the age of particular Triassic deposits, and whether they contain the oldest potential dinosaurs, does nothing to support a world created a few thousand years ago. Even the proposed adjustment involves a span of time vastly greater than young-Earth creationism allows for the entire history of the Universe.
The research also illustrates why scientific knowledge improves. Fossils can be re-examined, identifications challenged and geological correlations revised. Researchers publish the evidence and reasoning that allow other specialists to scrutinise their conclusions. An earlier interpretation has no entitlement to survive simply because it is familiar or appears in an authoritative publication.
There is no equivalent route to correction in a system that requires every conclusion to agree with a predetermined reading of Genesis. Within that constraint, conflicting evidence must always be explained away; the preferred answer cannot be allowed to fail. Science makes progress precisely because its explanations remain open to correction.
Dinodontosaurus isiyavamanda therefore brings creationists two unwelcome messages. Its place in deep time remains incompatible with their biblical chronology, while the research describing it demonstrates the willingness to question received wisdom that they so often claim scientists lack. Changing our understanding in response to evidence is how we discover our mistakes. Refusing to change merely preserves them.
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