One of the familiar refrains of creationism is that the fossil record contains no transitional forms. Yet transitions need not be preserved only in bones: sometimes, animals left evidence of evolutionary change in the footprints they made. A new study of ancient reptile tracks reveals a stepwise acquisition of features associated with upright locomotion — changes that helped establish the conditions for the later evolution of two-legged movement in dinosaurs and their close relatives.
The research, by Lorenzo Marchetti of the Museum für Naturkunde Berlin and Hendrik Klein of the Saurierwelt Paläontologisches Museum, is published in Palaeontology, concerns early archosauriforms, members of the wider evolutionary group that includes archosaurs — dinosaurs, pterosaurs, crocodilians and their relatives. Their history extends back into the Late Permian, more than 250 million years ago: already an insurmountable chronological problem for a literal reading of Genesis.
Marchetti and Klein re-examined footprints from the Val Gardena Sandstone Formation of northern Italy, including previously undescribed specimens, and recognised a distinctive track type, which they named Pachychirotherium gardenaensis. This is a name for the fossil traces, rather than a newly identified species of skeletal animal. Comparisons with fossil feet suggest that their makers were early archosauriforms with an anatomy resembling that of erythrosuchids.
The wider comparison with Permian and Triassic tracks is particularly revealing. Late Permian forms retain evidence consistent with sprawling locomotion; some Early Triassic forms show transitional characteristics; and a fully erect stance probably emerged during the Middle Triassic. Increasing reliance on the toes, changes in toe proportions and a reduction in the relative size of the forefoot impressions accompanied this evolutionary transition. These features were assembled progressively, rather than appearing together as a completed package.
Creationists who insist that there are no transitional fossils might wish that palaeontologists would stop finding animals that refuse to respect their imaginary boundaries. A newly described Jurassic bird from China is another such inconvenience: an evolutionary mosaic combining bird-like features with conspicuously dinosaurian anatomy. And, to compound the difficulty for Bible literalists, it lived approximately 150 million years ago — long before their supposed ‘Creation Week’.
The animal, Yuezhuornis yangyuanensis, discovered in the Late Jurassic Zhenghe Fauna of Fujian Province, is described in a paper published in Nature. This crow-sized animal possessed bird-like pelvic and hindlimb features alongside serrated teeth and a hyperextensible second toe bearing a sickle-shaped claw — a combination reminiscent of its close dinosaurian relatives.
Its unusually short forelimbs provide another intriguing part of the story. Analyses of its limb proportions strongly support a terrestrial, flightless lifestyle, despite its placement within Avialae, the evolutionary group containing living birds and their closest extinct relatives. The researchers interpret it as evidence of exceptionally early flight loss. That interpretation necessarily involves reconstructing ancestral capabilities: the fossil provides anatomical evidence about how this animal lived, rather than a direct record of either its behaviour or its ancestors’ flight.
This matters because evolution has no destination. Early birds were not obliged to become progressively better flying machines, any more than every mammalian lineage was obliged to become a bat. Natural selection favours traits according to their consequences in particular environments; it does not work towards a predetermined ideal. A lineage exploiting opportunities on the ground could follow a different evolutionary course from one increasingly dependent on flight.
About 150 million years ago, a small, feathered dinosaur was negotiating one of the most consequential transitions in vertebrate evolution: getting airborne and remaining there under its own power. Archaeopteryx, with its feathered wings, toothed jaws, clawed fingers and long, bony tail, combined features that creationists prefer to imagine belong in separate, independently created categories. It also lived almost 150 million years before the supposed ‘Creation Week’ of young-Earth creationism. Both its anatomy and its antiquity present awkward problems for anyone trying to compress the history of life into a literal reading of Genesis.
Now, a paper in Developmental Biology, by Erik A. Meilak and colleagues, addresses a particularly interesting question: how could an animal with a less specialised flight apparatus than that of modern birds get off the ground? Their modelling suggests that powerful hindlimbs could have supplied the answer. A succession of forward leaps, potentially assisted by a wingbeat between jumps, could have built up sufficient speed for flapping flight.
For a modelled Archaeopteryx weighing about 400 grams, the researchers calculated that three leaps using both legs, or two with an intervening downward wingbeat, could have brought it to a sustainable flight speed of approximately seven metres per second. This provides a plausible route into the air without requiring the powerful, explosive take-off of many living birds. It is a proposed biomechanical solution, rather than direct evidence of an observed Jurassic behaviour, but it makes a specific evolutionary possibility testable.
That distinction matters because evolution does not require a modern bird’s entire flight apparatus to appear in one miraculous event. Existing structures can acquire additional functions, and useful intermediate combinations can precede the more specialised arrangements found in descendants. Legs already capable of propelling an animal across the ground could also launch it into the air; feathered forelimbs could contribute to that movement before acquiring all the refinements of modern wings. No foresight is required, only advantages available to the animal at the time.
Nor does describing Archaeopteryx as transitional mean it was an unfinished creature waiting for evolution to complete it. It was an animal in its own right, with a revealing combination of ancestral and derived features. Birds are themselves theropod dinosaurs, so the transition concerns the emergence of avian specialisations within the dinosaur lineage, not a magical crossing between unrelated ‘kinds’. Calling Archaeopteryx “just a bird” does nothing to explain away its dinosaurian anatomy or its position in evolutionary history.
The study does not settle every question about the origin of flight, and it need not do so to expose the weakness of the creationist alternative. Science can investigate how a transitional animal functioned, compare competing explanations and refine its conclusions. A literal Genesis chronology cannot even accommodate the time in which that animal lived. In the following article, reproduced from The Conversation, co-author Neil J. Gostling explains how the research brings us closer to understanding the steps — or, in this case, leaps — by which early birds took to the air. His article is reformatted for stylistic consistency:
An artist’s rendering of the Norellraptor after an “exquisitely preserved” fossil with a complete skeleton and parts of its plumage was unearthed in Liaoning province.
a Right hand. b Pubis. c Feet. am, acetabular margin; ap, apron; cs, claw soft tissue; gi, gastral impression; mcI-III, metacarpals I to III; mtI-V, metatarsals I to V; p, phalanx; pf, pubic foot; r, radius; sc, semilunate carpal; t, tibiotarsus; u, ulna; uI-III, unguals 1 to 3. Scale bar = 10 mm.
For creationists who insist that complex adaptations could only have appeared as complete, purpose-built packages, another feathered dinosaur has provided an awkward piece of evidence. Evolution does not require a finished flight apparatus to materialise in a single miraculous leap. It can modify inherited structures, combine them in new ways, and produce similar adaptations along different branches of the family tree. A newly described dinosaur from China adds evidence that even among the close relatives of birds, there was more than one evolutionary route towards an aerial lifestyle.
In a paper published in Nature Communications, Xuri Wang and colleagues describe Norellraptor barsboldi, a small microraptorine dinosaur from the Lower Cretaceous Jiufotang Formation of Liaoning, north-eastern China. Its remarkably complete, 57-centimetre skeleton preserves traces of plumage, including on its forelimbs and hindlimbs. It belonged to the group of feathered dinosaurs famous for their four-winged forms: evolutionary relatives of birds, rather than evidence that modern birds appeared fully formed and unrelated to other dinosaurs.
The crucial finding concerns the sequence in which adaptations arose. The researchers’ evolutionary analysis indicates that approximately 30 per cent of the derived anatomical features identified in microraptorine evolution also evolved independently in the bird lineage. However, they appeared in different orders. This supports the gradual assembly of flight-associated anatomy under different selective pressures, rather than the inheritance of an already completed flight apparatus from a common ancestor.
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.
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Creationism’s problems with the fossil record now extend even to dinosaur droppings. A small piece of fossilised dung from Montana preserves evidence of a meal eaten some 66 million years ago — long before the supposed ‘Creation Week’ of young-Earth creationism. Within it are feathers that may help illuminate why some ancient birds disappeared while the ancestors of today’s birds survived.
As, reported in Current Biology, researchers led by Field Museum palaeontologist Jingmai O’Connor, examining a coprolite — fossilised faeces — from the Hell Creek Formation found exceptionally preserved feathers alongside fish scales and bones belonging to a hesperornithiform, an extinct diving bird.
The feathers combine structures associated with waterproofing in modern aquatic birds with smaller, simpler, fuzzy body feathers. The researchers suggest that differences in insulation, feather replacement through moulting, or both might have influenced which bird lineages survived the cold conditions following the end-Cretaceous asteroid impact. Hesperornithiforms disappeared; the lineage containing all living birds survived. This remains a hypothesis, however: one coprolite cannot establish why entire groups became extinct. The distinction between the observed feathers and the proposed explanation is central to the Field Museum’s account of the findings.
For creationists, the difficulty goes beyond the date. This combination of ancestral and more derived features makes sense within an evolutionary family tree, in which different characteristics change at different rates. Evolution does not require every part of an animal to move together along some imaginary ladder from ‘primitive’ to ‘advanced’. Nor does an extinct bird need to be a direct ancestor of living species to preserve evidence of the evolutionary history they share.
There is also a useful lesson here about adaptation. A feature that works adequately in one environment may become a liability when conditions change. Evolution has no foresight: natural selection cannot prepare organisms for an asteroid impact millions of years in the future. Survival depends on the circumstances organisms encounter and the characteristics they already possess, with chance also playing its part.
What makes this discovery particularly telling is how an apparently unpromising object can yield evidence against which explanations can be tested. Scientists can investigate both the history of feathers and the unresolved details of extinction without invoking a designer. The uncertainty concerns which natural factors mattered most — and further fossils may help resolve it. Even a dinosaur’s discarded meal can contribute to that process.
Oblique view of the lower part of the surface from the east, showing the general extent of the exposed palaeosurface. People for scale. Red arrow indicates the pit.
Artistic reconstruction of the Mullurina Mayu bowl-shaped depression during the Late Cretaceous, depicting the probable tracemakers responsible for the Calorckosauripus trackways and possibly the bowl-shaped depression.
Some 67 million years before creationists believe their god created Earth during its mythical six-day “Creation Week”, a group of enormous, long-necked dinosaurs walked across the soft mud beside a river or lake in what is now Bolivia. At least one large animal may also have stopped to scrape repeatedly at the ground, leaving a great bowl-shaped depression surrounded by grooves and possible claw marks. Whether it was preparing a nest, digging for water or mineral salts, or doing something else entirely is uncertain, but the marks it left behind provide a rare glimpse of dinosaur behaviour shortly before the end of the Cretaceous Period.
The evidence comes from the Mullurina Mayu locality in the Maragua region, about 23 kilometres west of Sucre, Bolivia. There, an exposed surface of Maastrichtian-age claystone in the Lower Member of the El Molino Formation preserves several trackways attributed to titanosaurian sauropods. The tracks have been assigned to the trace-fossil species Calorckosauripus lazari, believed to have been made by comparatively non-derived titanosaurs.
Now, in a paper published in the journal Fossil Record, Christian A. Meyer, Jose Hugo Heymann, Edwin Chuca Ibarra, Eddy Laura Flores and Lara Sciscio have described an unusual structure preserved among those trackways. It is an irregular, bowl-shaped hollow measuring approximately 4.2 by 3.2 metres and reaching about 60 centimetres in depth. Around its walls are bundles of parallel grooves, roughly one centimetre wide and up to about 30 centimetres long, together with broader marks on the floor that may have been made by claws.
Impression of a Tyrannosaurus rex attacking an Edmontosaurus annectens
AI-generated image (ChatGPT 5.6 Sol)
Tooth traces on ulna HRS10076.
A) Ulna with black boxes indicating areas with tooth traces. B-C) Magnification of corresponding boxes from Fig 7A. White arrows indicate pits and red arrows indicate parallel scores.
Last month produced the usual crop of research papers which, quite incidentally, refuted creationism simply by revealing evidence utterly incompatible with its basic dogmas. It also produced another answer to a favourite creationist conspiracy theory: that scientists are not permitted to publish anything that challenges the supposedly ‘materialist orthodoxy’ of the scientific establishment.
This allegation confuses philosophical materialism with methodological naturalism. Science confines itself to explanations that can be tested against evidence. That is a working method, not a compulsory metaphysical belief. Findings that challenge established interpretations are not prohibited; provided they are supported by evidence and survive critical scrutiny, they are an essential part of the way science advances.
Literalist creationism works in the opposite direction. It begins with the non-negotiable conclusion that scripture must be inerrant, so any contrary evidence must be denied, explained away or forced into conformity with that predetermined belief. Changing one’s mind in response to evidence is therefore treated not as intellectual honesty but as a failure of faith.
Creationists consequently try to have it both ways. When scientists agree, this is presented as evidence of a conspiracy suppressing dissent; when scientists challenge or refine an earlier interpretation, it supposedly proves that scientists are always changing their minds and that science is therefore unreliable. It is a convenient rhetorical trick in which both consistency and self-correction are declared to be evidence against science.
A modest but revealing example is a study published recently in PLOS ONE by researchers from Loma Linda University, Western University of Health Sciences, The Master’s University, Southern Adventist University and Southwestern Adventist University. Four of those five institutions are explicitly Christian: Loma Linda, Southern Adventist and Southwestern Adventist are Seventh-day Adventist universities, while The Master’s University declares a commitment to Christ and ‘biblical fidelity’. So much for the supposed exclusion of religious scientists from mainstream scientific publication.
The paper itself is not creationist research: it employs standard palaeontological methods and places the fossils within the conventional Maastrichtian stage of the Late Cretaceous. What it does show is that evidence-based research can be published and scrutinised irrespective of the religious affiliations of the institutions involved.
The researchers examined 3,013 dinosaur bones, most belonging to Edmontosaurus annectens, excavated between 1997 and 2017 from the Hanson Ranch Station bonebed in the Lance Formation of eastern Wyoming. Thirteen bones initially displayed perforations or other features that resembled tooth traces. Closer examination—including microscopy, comparison with other fossils and, in an ambiguous case, CT scanning—showed that one specimen contained normal openings in the bone, or foramina, rather than bite marks. The remaining 12 bones, just under 0.4 per cent of the total examined, preserved genuine tooth traces.
Four of those bones carried particularly diagnostic traces known as Knethichnus parallelum and Linichnus serratus. By comparing the spacing of the preserved striations and serrations with the denticles on carnivorous dinosaur teeth recovered from the same bonebed, the researchers identified Tyrannosaurus rex as the most likely culprit. Other, less diagnostic marks may have been produced by crocodilians living in the same ecosystem.
Most of the tooth traces showed no associated bone remodelling, suggesting that they were inflicted at or after the time of death. The evidence therefore points more strongly towards scavenging than successful predation, although the two cannot always be distinguished. Weathering, bioerosion and characteristic fractures in fresh bone also indicate that the carcasses remained exposed for some time before burial and were probably exploited by theropods, crocodilians or both.
It is gap-filling time again — not because palaeontologists have discovered some predetermined evolutionary “missing link”, but because another conspicuous blank on the palaeontological map is being filled. This time, the new evidence comes from Africa and concerns a dinosaur that lived about 210 million years ago, during the Late Triassic.
The discovery sheds new light on the early diversification and geographical distribution of dinosaurs, when they were still only a relatively minor component of terrestrial ecosystems. Over the following millions of years, they diversified into an extraordinary range of forms and became the dominant large land animals of the Jurassic and Cretaceous periods.
Gaps in the fossil record are, of course, eagerly seized upon by creationists desperate to find somewhere to insert their god. Their enthusiasm tends to diminish markedly whenever palaeontologists recover new evidence from one of those gaps. Each such discovery removes another supposed refuge for the ever-shrinking god of the gaps, so the evidence must be dismissed as misidentified, incorrectly dated or merely another example of “evolutionary storytelling”.
No matter how many gaps science fills, creationists continue to assure themselves that the next one will be different: that it will finally be the gap that science cannot investigate and into which their preferred creator can safely be inserted. Unfortunately for that strategy, palaeontologists continue to discover fossils, dating methods continue to improve, and previously neglected regions continue to be explored.
This latest discovery consists of a partial skeleton excavated from exposures of the Late Triassic Pebbly Arkose Formation on the shore of Lake Kariba in northern Zimbabwe. An international team of Zimbabwean, South African and British scientists has named the animal Musango matusadonaensis. The study was led by Professor Paul M. Barrett of the Natural History Museum, London, while the expeditions during which the fossils were collected were led by Professor Jonah Choiniere of the University of the Witwatersrand’s Evolutionary Studies Institute.
Musango was an early sauropodomorph — a member of the lineage that later produced the enormous, long-necked sauropods such as Diplodocus. Unlike those gigantic four-legged descendants, however, Musango was a relatively lightly built, predominantly bipedal animal. It measured an estimated 4.5 metres in length but weighed only about 222 kilograms. Its skull has not been recovered, so its diet cannot be established with certainty, although comparisons with related dinosaurs suggest that it was probably herbivorous or omnivorous.
The fossil record of early dinosaurs is extremely uneven. Europe, North America and parts of South America have been studied far more intensively than much of Africa, leaving large gaps caused not necessarily by the absence of dinosaurs but by the scarcity of sustained palaeontological exploration. Musango is only the fifth dinosaur formally named from Zimbabwe, following the description in 2024 of another sauropodomorph from the same formation, Musankwa sanyatiensis.
Phylogenetic analysis places Musango and Musankwa as close relatives within Unaysauridae, a group whose fossils are known from Africa, India and South America — landmasses that were then joined within Gondwana. Together, these discoveries support an emerging picture in which Late Triassic southern Africa contained several distinct ecosystems with their own dinosaur communities, rather than a single uniform fauna extending across the region. Africa was therefore not a peripheral spectator in early dinosaur evolution; its still-underexplored rocks may preserve crucial evidence about how dinosaurs diversified and spread before their later ecological dominance.
Young-Earth creationists are fond of pointing out that a single flood or storm can deposit a layer of sediment very quickly, as though this somehow proves that the entire geological record could have been produced during the mythical year-long flood described in Genesis. But the speed with which an individual layer forms tells us nothing about the intervals between successive layers. When those layers contain regular, measurable cycles produced by processes operating daily, fortnightly and seasonally, they become a record of elapsed time—and that time cannot simply be waved away.
An article in The Conversation by palaeontologist Alfio Alessandro Chiarenza of University College London describes just such a record. It concerns the Villaggio del Pescatore fossil site near Trieste, north-eastern Italy, where dinosaurs, crocodilians, fish, shrimps, plants and other organisms were preserved with exceptional detail about 80 million years ago.
Chiarenza and his colleagues, led jointly with Federico Fanti of the University of Bologna, have published their findings in the journal Global and Planetary Change. Their evidence shows that the site was not, as previously proposed, a quiet lake or sinkhole. It was a tropical tidal flat on the edge of an ancient sea, repeatedly affected by powerful monsoon floods and tropical cyclones.
The fossil-bearing limestone consists of metre-thick packages containing thousands of discrete, paper-thin light and dark layers. These had previously been interpreted as annual deposits, or varves. However, high-resolution synchrotron X-ray scanning, microscopic and geochemical analyses, and statistical analysis of the repeating patterns revealed something still more remarkable: the layers are tidal microcouplets, laid down under a semidiurnal tidal regime—two tidal cycles each day.
Moreover, variations in the thickness of the layers follow the familiar fortnightly alternation between spring and neap tides. The rocks therefore contain not merely a succession of vaguely similar bands, but an ordered astronomical rhythm produced by the interaction of Earth’s rotation with the orbit of the Moon. By counting and analysing those layers, the researchers calculated that the fossil-bearing succession accumulated over approximately 40 years. In other words, the rock preserves an almost day-by-day record extending across four decades.
That presents creationists with a problem that cannot be dismissed by claiming that “floods can deposit sediment rapidly”. Of course they can; that is precisely what some of the layers record. But a single flood cannot manufacture 40 years’ worth of successive twice-daily tidal deposits, arranged in the correct fortnightly spring–neap pattern. Still less can the supposed year-long biblical flood accommodate a geological sequence that records some 40 years of tides within one small part of a vastly larger, 80-million-year-old succession.
In my previous post, I wrote about Labrujasuchus expectatus, a bizarre distant relative of the crocodile line which walked on two legs, had tiny arms, and possessed a toothless mouth tipped with a beak. Although not a dinosaur, it looked superficially dinosaur-like — a neat example of convergent evolution. Because earlier and later shuvosaurids were already known from the region, palaeontologists predicted that a form occupying the gap between them should exist, and Labrujasuchus duly turned up in the right place and in the right rock formation.
That is how science works: evidence fits into a testable, predictive framework. Creationism, by contrast, has nothing to offer except hand-waving, misrepresentation and denial when confronted with a bizarre extinct archosaur from some 212 million years ago, just as it has nothing to offer in explanation of this almost equally bizarre dinosaur from about 70 million years ago.
The new species, Kank australis, is described by palaeontologist Dr Matías J. Motta, of the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires (Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”), and his colleagues in a paper published on 28 May 2026 in the peer-reviewed Journal of Vertebrate Paleontology.
Kank australis was a paravian theropod — an unenlagiid, belonging to a group of small- to medium-sized raptor-like dinosaurs known from Late Cretaceous Gondwanan deposits. Its discoverers suggest that it may have lived rather like a large heron. Its long jaws, armed with teeth, suggest a fish-eating habit, while its cervical vertebrae show structures associated with muscle attachment and the protection of neck blood vessels, features comparable with those seen in modern birds that rely on rapid, precise neck movements. In other words, this was probably not the familiar pop-culture image of a raptor as a fast-running terrestrial predator, but a specialised animal exploiting the riverine and wetland ecosystems of southern Patagonia.
And, as so often with new fossil discoveries, Kank australis fills in yet another of those gaps so beloved of creationists looking for somewhere to hide their ever-shrinking little god. In this case, it helps bridge a distributional gap in the Late Cretaceous record of southern Patagonia, connecting better-known unenlagiid records from northern Patagonia with those from Antarctica, and adding more detail to the still-patchy evolutionary history of these South American paravian dinosaurs.
Evolution, proceeding without a plan and lacking any sense of direction, can produce some truly bizarre creatures which, despite their appearance, survived perfectly well in the environments in which they evolved. Indeed, it would be bizarre to suppose otherwise, given that natural selection favours those forms that work well enough to survive and reproduce over those less well fitted to do so. To suppose otherwise would rival creationism for irrationality.
In this post, I’ll deal with a bizarre distant relative of the crocodiles; in the next, I’ll write about a strange theropod dinosaur from 70 million years ago that comes close to what any creationist might imagine a transitional species between dinosaurs and birds should look like.
Creationism is, of course, itself the product of an evolutionary process, forced into ever more bizarre forms by the hostile environment of scientific evidence. Modern creationism has therefore, by a similar process, become almost as bizarre as the life forms it is forced to deny in order to survive.
The sad thing is that creationists are denied the wonder of the truth about our planet as revealed in increasingly astonishing detail by science, because the facts must be waved aside and denied in order to cling to the childishly simplistic belief in magic and a world full of evil conspirators diligently working to trick them into changing their minds.
Who, for example, could have predicted that a distant relative of the crocodiles walked on two legs, had tiny arms, and had a toothless mouth tipped with a beak? It is almost as bizarre as the mental gymnastics creationists need to perform to dismiss it and force-fit the evidence into the predetermined conclusion that it must have been magically created within the last few thousand years and then allowed to go extinct for no apparent purpose — or that the evidence must either have been forged, misinterpreted or planted to test or deceive us.
Nevertheless, this creature, Labrujasuchus expectatus, did exist about 212 million years ago, in the Late Triassic, and its description is the subject of a recent paper in the Journal of Vertebrate Paleontology. Its fossilised remains were unearthed in Late Triassic rocks at the Hayden Quarry, Ghost Ranch, New Mexico, USA, by a team of palaeontologists led by Dr Alan H. Turner of Stony Brook University, New York, USA, with colleagues including Dr Nathan D. Smith of the Natural History Museum of Los Angeles County, Los Angeles, California, USA.
To add insult to injury for creationists, this find fills one of those beloved gaps into which creationists try to force fit their creator god. The gap was that between two earlier discovered shuvosaurs from the region. It's discovery was thus a predicted by the Theory of Evolution, not by a book of Bronze Age mythology.
Although they may have retained some residual function, what the forelimbs of Tyrannosaurus rex were almost certainly not used for was grabbing and holding large prey. They were far too short and mechanically limited for that role, especially in a predator whose real killing equipment was a massive skull, powerful jaws and bone-crushing bite. So, creationists need to explain why an intelligent designer would have equipped one of the most formidable predators ever to walk the Earth with such apparently inadequate little arms in the first place.
These apparent design failures are, of course, entirely understandable as the result of an evolutionary process operating over deep time. Just such an explanation has now been proposed by three researchers from University College London (UCL) and the University of Cambridge, who have published their findings in Proceedings of the Royal Society B. It almost goes without saying that their explanation is an application of the Theory of Evolution, with no suggestion that the authors are about to abandon it in favour of creationism — as creationists have been confidently predicting for the best part of half a century, despite the singular lack of any peer-reviewed scientific movement in that direction.
The researchers found a strong association between the evolution of large, robust skulls and the reduction of forelimbs in several groups of non-avian theropod dinosaurs. In other words, the tiny arms of T. rex were not merely a side-effect of the whole body becoming larger. They were more closely linked to the evolution of powerful heads and jaws, suggesting a shift in hunting strategy in which the skull became the principal weapon and the forelimbs became less important.
The authors are careful to point out that correlation does not prove causation. But the pattern is consistent with an evolutionary arms race in which large predatory dinosaurs increasingly relied on massive skulls and crushing bites to tackle large prey, rather than on grasping forelimbs. As lead author Charlie Roger Scherer put it, trying to grab and hold a huge herbivorous dinosaur with claws would not have been ideal; attacking and holding with the jaws may have been far more effective.
For their study, the researchers developed a new way to quantify skull robustness, using factors such as how tightly the bones of the skull were connected, the compactness of the skull, and bite force. On this measure, T. rex scored highest, followed by Tyrannotitan, a large South American theropod that lived more than 30 million years earlier.
The study also showed that forelimb reduction evolved independently in at least five theropod groups: tyrannosaurids, abelisaurids, carcharodontosaurids, megalosaurids and ceratosaurids. That makes this a case of convergent evolution: different lineages arriving at a similar anatomical result because similar selective pressures favoured a similar functional solution.
The evolutionary sequence is straightforward in this case: as the prey became larger so the jaw and skull needed to become larger to kill and consume the prey. The mouth then became the primary means of gripping and killing the prey and the forelimbs, which are not needed for locomotion, became increasingly redundant but liable to injury, so there was an advantage in reducing their size. The fact that there was convergence in different lineages, is strongly suggestive that this mechanism evolved for the same reasons, multiple times.
The Evolution of the Tyrannosaurs.
Tyrannosaurus rex was not the starting point of the tyrannosaur story, but one of its final and most extreme products. The wider group, Tyrannosauroidea, had a long evolutionary history stretching back into the Middle Jurassic, more than 100 million years before T. rex. For much of that time, tyrannosauroids were not gigantic apex predators, but mostly small to medium-sized, lightly built theropods living alongside, and often in the shadow of, other large carnivorous dinosaurs.[1]
Early tyrannosauroids included animals such as Proceratosaurus from Jurassic Britain and Guanlong from Jurassic China. These were not simply miniature versions of T. rex. Some had crests, longer arms and more generalised predatory bodies. Their importance lies in showing that tyrannosaurs did not appear suddenly as fully formed, giant, short-armed killing machines. The famous late Cretaceous body plan was assembled gradually, piece by piece, over tens of millions of years.[1,2]
Several Early Cretaceous tyrannosauroids also show how different the early members of the group were from their later descendants. Dilong paradoxus, from China, was small and gracile, with relatively long arms and three-fingered hands. It also preserved evidence of filamentous protofeathers, showing that at least some early tyrannosauroids were not the purely scaly monsters of older popular reconstructions.[3]
The discovery of Yutyrannus huali, also from Early Cretaceous China, pushed that point further. This was a much larger tyrannosauroid, yet it too preserved long filamentous feathers. That does not prove that an adult T. rex was fully feathered, and skin impressions from later tyrannosaurids suggest at least some scaly areas. But it does show that feathers were part of the wider tyrannosauroid evolutionary background, not an irrelevant bird-like novelty.[4]
By the Late Cretaceous, especially in Asia and western North America, tyrannosaurids had become the dominant large predators. Genera such as Albertosaurus, Gorgosaurus, Daspletosaurus, Tarbosaurus and Tyrannosaurus show the familiar trend towards massive skulls, powerful jaws, thick teeth, strong hind limbs, keen senses and reduced forelimbs. This was not a single act of design, but a long evolutionary sequence in which the skull and jaws increasingly took over the role of subduing prey.[1,5]
Recent work has added further detail to this picture. In 2025, researchers described Khankhuuluu mongoliensis, a Mongolian tyrannosauroid from the lower Upper Cretaceous, as a form close to the origin of Eutyrannosauria — the group that includes the large, late Cretaceous tyrannosaurs. Their analysis suggests a complex history of dispersal between Asia and North America, with tyrannosaur evolution involving migration, ecological opportunity and divergent growth patterns, rather than a simple straight-line progression from small ancestor to giant descendant.[6]
So the tiny arms of T. rex are not an isolated oddity needing to be excused as good design. They are part of a broader evolutionary pattern in which tyrannosaurs changed from relatively small, long-armed predators into large, skull-dominated apex predators. The result looks puzzling if imagined as the work of a designer starting from scratch, but it makes sense as the outcome of descent with modification, changing ecological pressures, and the evolutionary reworking of inherited anatomy.
The publication in Proceedings of the Royal Society B is accompanied by a news release from UCL.
Why meat-eating dinosaurs like T. rex evolved tiny armsThe evolution of tiny arms in several groups of meat-eating dinosaurs was likely driven by the development of strong, powerful heads, which were used to attack prey, according to a new study led by researchers at UCL and Cambridge University.
The study, published in the journal Proceedings of the Royal Society B, looked at data for 82 species of theropod (two-legged, mainly meat-eating dinosaurs), finding that shortening of forelimbs occurred across five groups, including tyrannosaurids, the family that included Tyrannosaurus rex.
The team, including Dr Elizabeth Steell at Cambridge and Professor Paul Upchurch at UCL, found that smaller arms were closely linked to the development of large, powerful skulls and jaws, more so than to larger overall body size, indicating that tiny arms were not just a by-product of bodies getting bigger.
The researchers suggested that the increasing size of prey, in the form of gigantic sauropods (long-necked, long-tailed plant-eaters) and other large herbivores, may have resulted in a shift to hunting using jaws and head instead of claws.
Everyone knows the T. rex had tiny arms but other giant theropod dinosaurs also evolved relatively small forelimbs. The Carnotaurus had ridiculously tiny arms, smaller than the T. rex. We sought to understand what was driving this change and found a strong relationship between short arms and large, powerfully built heads. The head took over from the arms as the method of attack. It’s a case of ‘use it or lose it’ – the arms are no longer useful and reduce in size over time. These adaptations often occurred in areas with gigantic prey. Trying to pull and grab at a 100ft-long sauropod with your claws is not ideal. Attacking and holding on with the jaws might have been more effective.
While our study identifies correlations and so cannot establish cause and effect, it is highly likely that strongly built skulls came before shorter forelimbs. It would not make evolutionary sense for it to occur the other way round, and for these predators to give up their attack mechanism without having a back-up.
Charlie Roger Scherer, lead author.
Department of Earth Sciences
University College London
London, UK.
For the study, researchers developed a new way to quantify skull robustness, based on factors including how tightly connected the bones of the head were, the dimensions of the skull (a more compact shape is stronger than an elongated shape), and bite force.
On this measure, the T. rex scored highest, followed by the Tyrannotitan, a theropod nearly as massive as T. rex who lived in what is now Argentina in the Early Cretaceous period (more than 30 million years earlier than T. rex).
The team said that increasingly gigantic prey may have resulted in an “evolutionary arms race”, where theropods developed strong skulls and jaws to better subdue this prey, and in many cases grew to gigantic sizes themselves.
Separately, the team compared forelimb length to skull length, classifying five groups of dinosaurs as having reduced forelimbs: tyrannosaurids, abelisaurids, carcharodontosaurids (including the Tyrannotitan), megalosaurids and ceratosaurids.
They found reduced forelimbs had a stronger link with skull robustness than with skull size or overall body size. The secondary importance of overall body size was illustrated by the fact that some theropods with strongly built heads and tiny arms were not very large, the researchers said, citing the Majungasaurus, an apex predator in Madagascar 70 million years ago, but weighing a mere 1.6 tonnes, about a fifth of the T. rex.
The researchers noted that the forelimbs appeared to reduce in size in different ways, with hands and the lower part of the arm (past the elbow) shortening the most in abelisaurids (with late abelisaurids such as the Majungasaurus having exceptionally tiny hands). In tyrannosaurids, on the other hand, each element of the forelimb was reduced at a similar rate.
The team concluded that the same outcome (tiny forelimbs) was likely achieved through potentially different developmental pathways in different species.
A team of five academics work on different aspects of dinosaur evolution at UCL, with strong collaborative links to the Natural History Museum. The extended research group comprises four research fellows and postdoc researchers, and more than 10 PhD students. At least four of the PhD students are working on dinosaur evolution, with the others looking at a wider array of other evolutionary questions relating to vertebrates, including crocodiles and birds.
Abstract
Forelimb reduction has been observed in numerous and disparate non-avian theropod dinosaurs, resulting in the hypothesis that reduced forelimbs evolved convergently. Clades with reduced forelimbs also possess high degrees of cranial robusticity and gigantic body sizes. Here, we provide a novel quantification of forelimb reduction across Theropoda, and create and implement a cranial robusticity scoring system, and analyse this dataset using bivariate and comparative phylogenetic analyses. Results indicate that forelimb reduction is strongly correlated with cranial robusticity and gigantism. Reduced/vestigial forelimbs evolved in at least five theropod lineages in concert with increased cranial robusticity and gigantism. Abelisaurids, carcharodontosaurids and tyrannosaurids show the greatest forelimb reduction relative to the skull. Repeated forelimb reduction across theropods was facilitated by increased cranial robusticity and greater body size that was potentially influenced by an upward trend in prey body size. These events resulted in a shift from subduing prey using grasping forelimbs to using powerful bites and robust skulls.
So the famously tiny arms of Tyrannosaurus rex are not an embarrassment for evolutionary biology; they are exactly the sort of thing evolution explains. They are the result of history, contingency and trade-offs: inherited anatomy being modified over time as natural selection favoured a different way of killing prey. As the skull became larger, stronger and more effective as the main predatory weapon, the forelimbs became less important, and so there was no evolutionary pressure to maintain them as large, powerful grasping organs.
That is why this feature is so difficult to explain as the work of an intelligent designer. A designer starting from scratch could simply have produced an animal with both a massive, bone-crushing skull and proportionately useful forelimbs, or dispensed with the arms altogether. Instead, what we see is the familiar evolutionary pattern: not perfect engineering, but modified inheritance; not clean-sheet design, but anatomical compromise shaped by changing selection pressures.
Creationism has no scientific explanation for this. It can only wave the problem away by declaring, without evidence, that the tiny arms must have had some unknown purpose, or that the designer’s motives are beyond human understanding. But that is not an explanation; it is an excuse for not having one. It predicts nothing, explains nothing, and adds nothing to our understanding of tyrannosaur biology.
The Theory of Evolution, by contrast, not only explains why such apparently odd features exist, but also provides a framework in which they can be tested. The prediction is that similar ecological and functional pressures should produce similar anatomical trends in separate lineages — and that is exactly what this study found. Forelimb reduction evolved independently in several theropod groups, associated not with divine whim, but with the repeated evolution of large, robust skulls and powerful jaws.
In other words, the tiny arms of T. rex are not a mystery for science; they are evidence of evolution doing what evolution does — adapting existing structures to changing circumstances, often imperfectly, always historically, and never with the foresight or tidiness that intelligent design would require. Once again, the evidence fits the evolutionary model and leaves creationism with nothing more substantial than incredulity, special pleading and the hope that no one looks too closely.
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