Feeding hagfish
Credit: National Oceanic and Atmospheric Administration (NOAA),
Public domain, via Wikimedia Commons
Public domain, via Wikimedia Commons
Showing posts with label Biology. Show all posts
Showing posts with label Biology. Show all posts
Sunday, 7 June 2026
Creationism Refuted - British Fallow Deer Have LOST Genetic Diversity - Over The Last 120,000 Years
A paper just published in iScience should, if they were aware of it, at least cause an honest creationist to question some basic assumptions. It reports that modern European fallow deer, Dama dama, retain only a fraction of the genetic diversity present in their Ice Age ancestors. This finding is based on ancient DNA recovered from the fossilised remains of ten, approximately 120,000-year-old fallow deer from Neumark-Nord in Germany, analysed by researchers from the University of Potsdam, the MONREPOS Research Center and Museum in Neuwied, and Leiden University in the Netherlands.
Creationism continues to take a battering in the world of real science, where yet another paper quite incidentally refutes several of its basic dogmas. Creationists, who are notoriously reluctant to read serious science and would probably struggle to understand it if they did, will no doubt remain blissfully unaware of this constant refutation of their core superstitions.
To ensure that ignorance is maintained, creationist disinformation sites expend considerable effort in spreading distrust of serious science amongst their followers. What cult leader would want his followers reading anything that exposes his claims as bogus?
However, ignoring the facts does not make them go away, and the facts this paper reveals go to the heart of creationist mythology. Firstly, this evidence should not exist at all if the Bible creation myth were real history: a magical creation just 6,000-10,000 years ago, followed by a catastrophic global genocide, would leave no room for a 120,000-year-old population of fallow deer preserved in an Eemian lake environment. Secondly, it undermines the creationist parody of evolution that they so often attack: the false claim that evolution must always mean increasing complexity, and that any loss of genetic information is invariably fatal.
The reduced genetic diversity of modern fallow deer is a clear example of evolution involving a loss of genetic variation within a population. So far as individual deer are concerned, there need be no immediate reduction in fitness; the problem comes when a population has less capacity to respond to environmental change, disease, or other selective pressures, and may then be more vulnerable to extinction. Evolution, of course, has no plan. Unlike intelligent design, or even guided evolution, it cannot foresee future conditions and prepare a species for them. A species can be driven towards extinction by the simple operation of mindless natural processes.
Saturday, 6 June 2026
Refuting Creation - With Goethe's 40-Million-Year-Old Ant
Amber piece 1552.b showing bioinclusions. Arrow in a (top): inclusion of †Ctenobethylus goepperti; arrow in b (bottom): inclusion of the Sciaridae. Scale bar 5 mm.
Some years ago, while staying for a few days in Berlin in a hotel just off Goethestraße, I made the mistake of telling a taxi driver that our hotel was just off “Go-eth Straße”. It took several minutes and a map to sort out the confusion.
“Nein! Goethe-Straße!” he laughed. Only then did I realise that “Go-eth” and “Goethe” were not two different German philosophers.
“Ach ja! Danke! Goethe! Ich bin ein Engländer!” I explained, in my best German.
“Ja! Is better we speak English,” he replied.
Goethestraße — Goethe Street — is, of course, named after Johann Wolfgang von Goethe (28 August 1749 – 22 March 1832), the German writer, poet, novelist and playwright. He was also an administrator, scientist, geologist, botanist and philosopher. As a naturalist and collector, he left behind an extensive geological and mineralogical collection, including 40 pieces of Baltic amber, which have now been closely examined by biologists at Friedrich Schiller University Jena — appropriately enough, since Goethe and the playwright Friedrich Schiller were friends.
What they found was the subject of a paper in Scientific Reports, published in January 2026. It is not good news for creationists, since it concerns an approximately 40-million-year-old ant, preserved in exquisite detail and now visible using modern imaging techniques such as synchrotron micro-computed tomography. In addition to the ant, the scientists also found a fungus gnat and a blackfly in Goethe’s amber.
It is unlikely that Goethe knew these creatures were preserved in his amber, since the pieces are unpolished and the contents are barely visible to the untrained eye. He certainly could not have known that the amber was tens of millions of years old. Had he known, we can only speculate how that knowledge might have affected his view of nature, time and human origins. His famous work, Faust, draws deeply on Christian motifs, including the story of a man who makes a pact with the Devil; but Goethe was also a serious observer of nature, living at a time when geology, palaeontology and evolutionary thinking were still in their infancy.
In the early nineteenth century, Europeans had not yet accumulated the overwhelming evidence that Earth is billions of years old and that life has changed profoundly over vast periods of time. Many educated people still interpreted history, nature and morality through a biblical framework, even when their own thinking was more subtle than simple literalism. Goethe, despite his scientific curiosity, lived before Darwin, before modern stratigraphy was fully established, and long before modern imaging could reveal the hidden contents of an opaque piece of amber.
Now, of course, we know better, because of the tremendous scientific progress made over the last two centuries.
Friday, 5 June 2026
Refuting Creationism - Yet Another Gap Is Closing - No God Found
Complete skeleton of the oldest jack fish, part of the group that includes modern jacks and trevallies.
A close-up of sharp teeth in an early relative of modern tunas.
Images credit: Professor Hesham Sallam, Mansoura University Vertebrate Paleontology Center
Creationist dependence on these god-shaped gaps has produced an ever-shrinking god as science fills one gap after another with evidence. The fallacy depends on the gamble that, unlike every previous gap closed by science, this one will turn out to require a supernatural creation event. It never does, of course, but that never seems to diminish creationist confidence that the next gap will be different.
True to form, science has now closed yet another gap with evidence, not magic. It is one few creationists are likely to know about, and fewer still would be willing to acknowledge, because it concerns a gap in the fossil record between the K–Pg mass extinction, which eliminated the non-avian dinosaurs 66 million years ago, and about 56 million years ago. In other words, it is a 10-million-year interval in the very long pre-‘Creation Week’ history of life on Earth — a history no self-respecting creationist can honestly admit exists without conceding that the Bible’s creation myth is not real history. Specifically, it is a gap in the fossil record of fish evolution, from the devastation at the K–Pg boundary to the later appearance of many species that look markedly different from those that preceded it.
That gap, known to palaeontologists as “Patterson’s Gap”, has now been partly filled by the discovery of the earliest known examples of six modern fish groups by a research team led by Sanaa El-Sayed, a University of Michigan doctoral student and researcher at the Mansoura University Vertebrate Paleontology Center. The fossils were found in the Qreiya 3 Lagerstätte, dated to 62.2 million years ago, in Egypt’s Eastern Desert. The discovery has just been reported in Science Advances.
Thursday, 4 June 2026
Refuting Creationism - Wild Cattle Roamed The Grasslands Of Europe - 4 million Years Before Creation Week
Palaeoartistic reconstruction of the environment in the surrounding of Camp dels Ninots maar lake during the early Pliocene.
Artwork by Mauricio Antón.
This is easily explained once we recognise that the authors of Genesis had a narrow, parochial view of the world. They knew little or nothing of Earth’s history or of the origins of life on it, so they made up stories that conformed to their own cultural assumptions and superstitions, often borrowing from neighbouring cultures.
They were completely unaware of the rest of Eurasia beyond their limited view from the Canaanite hills, and equally unaware of the great age of the Earth or the cycles of glacial and interglacial periods that had characterised it for the previous several million years. Indeed, the concept of such deep time seems to have been far beyond their comprehension. They could therefore have had no concept of the early forms of cattle-like bovines that once roamed Europe, already fitted by evolution for life in the changing environments of the Pliocene.
One such animal was a large bovine species, weighing up to about half a ton, which lived in what is now north-eastern Iberia about 4.41 million years ago. The discovery and re-analysis of this animal has just been published in PLOS One by Leonardo Sorbelli of the Leibniz Institute for Evolution and Biodiversity Science, Germany, and colleagues.
The fossils, from the Camp dels Ninots site in Catalonia, include remains from at least 14 individuals, among them eight nearly complete and partly articulated skeletons. The species, Parabos tigneresi, helps fill a gap in the evolutionary history of Eurasian bovines, including the wider lineage that eventually gave rise to modern cattle, bison and buffalo. Although smaller than many living domestic cattle, these animals were larger than comparable bovids of their time, suggesting an early stage in the increase in body size that later became characteristic of the bovine lineage.
The researchers suggest that this increase in size may have been associated with the climatic and environmental changes that characterised Pliocene Europe. The anatomy of Parabos tigneresi also indicates an animal adapted mainly to humid, vegetation-rich environments, consistent with the reconstructed setting of Camp dels Ninots as a water-rich maar lake ecosystem.
This incidental confirmation of an earlier reconstruction of the lake ecosystem at Camp dels Ninots is a good example of how independent strands of evidence converge on the same conclusion. It also illustrates the strength of Darwinian evolutionary theory: organisms are expected to show adaptations to the environments in which they lived, rather than appearing as arbitrary, ready-made forms. In this case, the anatomy of these bovids is consistent with animals adapted to a humid, vegetation-rich lakeside habitat, exactly as the geological and palaeoecological evidence had already indicated.
Tuesday, 2 June 2026
Refuting Creationism - The Evidence Shows How Wrong The Bronze Age Myths In The Bible Were
A crouched burial of a 40 year old man in Oostwoud, the earliest known Bell Beaker grave identified by the researchers.
Source: Provincial Depot for Archaeology Noord-Holland.
Leaving a side the long history of archaic hominins such as the Neanderthals and their ancestors inhabiting Western Eurasia for about 250,000 years before the arrival of large numbers of anatomically modern humans, which itself is deeply problematic for creationists, there is also the archaeological record of the complext history of modern humans going back at least 40,000 years which simply would not be there if the Bible narrative of a recent spontaneous magical origin and a later global genocidal flood were true.
As reported in a paper in Nature last February (2026), the history of Northwest Europe and the Bristic Isles is far mpre complex and interesting that the simple Bronze Age fairy tail in Genesis.
Of course, the arcahaeolgeneticists never set out to disprove the Bible. The facts they revealed did that as a matter of course, because unlike Genesis, the facts record real events.
The contrast could hardly be more stark. Genesis gives us a world populated from a single specially-created human pair, followed by a later repopulation of the world from Noah’s family after a global flood, and then the dispersal of peoples after Babel. That is a story of magical manufacture, catastrophic reset and sudden dispersal. The ancient DNA tells a completely different story: long-lived regional populations, gradual migration, intermarriage, cultural exchange, local ecological adaptation and no global genetic bottleneck compatible with a recent universal flood.
Sunday, 31 May 2026
Creationism Refuted - The Theory of Evolution May Be Slightly Wrong - But It's No Comfort To Creationists
Microscopic fungi, baker’s or brewer’s yeast, are used as probiotics to restore normal flora of intestine.
Image credit: Adobe Stock
A paper published in Nature Ecology & Evolution last november (2025) by four evolutionary biologists from the University of Michigan might have caused a stir of excitement in creationists cirles if any of them ever read a science paper because it appears on first sight to question the basis of the Theory of Evolution - what creationists call 'Dawinism'. However, that excitement would have been short-lived if they had read the details.
This is not the long-awaited collapse of the Theory of Evolution that creationists have been confidently predicting since at least the middle of the last century. It is nothing of the sort. It is a normal example of science doing what science does: testing a model against evidence, finding that the model is incomplete, and adjusting the explanation accordingly.
The theory being challenged here is not evolution itself, nor common descent, nor natural selection, nor mutation, nor population genetics. It is the neutral theory of molecular evolution, a theory developed in the 1960s to explain why many genetic changes appear to spread through populations without obvious adaptive advantage. The new paper argues that this appearance of neutrality may be misleading. What looks neutral in the long term may, in fact, be the result of short-term adaptation to changing environments.
The researchers found that beneficial mutations are more common than the classic neutral theory assumes. The problem, then, is why these apparently useful mutations do not become fixed at the rate one might expect. Their answer is beautifully evolutionary: environments change. A mutation that helps in one set of conditions may be useless, or even harmful, in another. So populations are not marching steadily towards some perfect design; they are continually tracking a moving target.
That is what the authors mean by adaptive tracking with antagonistic pleiotropy. “Pleiotropy” means that one mutation can have more than one effect. “Antagonistic” means that those effects can pull in opposite directions: helpful here, harmful there; useful now, costly later. This is not magic. It is not supernatural intervention. It is the ordinary interaction between genes, organisms and environments.
Creationists often pretend that science is an orthodoxy in which biologists merely defend Darwin at all costs. This paper shows the opposite. Scientists have examined one of their own long-standing theories, compared it with new evidence, and proposed a better explanation. No sacred text was protected. No dogma was shielded from scrutiny. No conclusion was declared immune from revision.
The result is not less evolution, but more evolutionary detail. Mutation still supplies variation. Selection still acts on differences in reproductive success. Genetic drift still matters. Environments still shape which variants succeed and which fail. What has changed is the understanding of how molecular change can appear neutral over deep time while still being shaped by episodes of adaptation in shifting environments.
So, far from helping creationism, this paper undercuts one of creationism’s favourite caricatures of science. It shows evolutionary biology as a living, self-correcting science, not a rigid ideology. It also shows why no supernatural designer is needed. The process described is entirely natural: mutations arise, their effects depend on circumstances, environments change, and populations respond as best they can, without foresight, plan or purpose.
Saturday, 30 May 2026
Refuting Creationism - Another Bizarre Dinosaur - From 70 Million Years Before 'Creation Week'
A reconstruction of Kank australis
Gabriel Díaz Yantén.
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.
Refuting Creationism - Bizarre Creature From The Long History of Earth Before 'Creation Week'
Reconstruction of Labrujasuchus expectatus, a new species of Shuvosauridae from Late Triassic rocks of Ghost Ranch, New Mexico
Art by Jorge Gonzalez, © NHMLAC Dinosaur Institute.
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.
Thursday, 28 May 2026
Refuting Creationism - How Our Blood Cells Have Evolved From Our Single-Celled Ancestor from 700 Million Years Ago
The origin of blood cells can be traced back approximately 700 million years to when human ancestors were single-celled organisms. When these ancestors evolved into multicellular organisms (animals), macrophages emerged as the first blood cells. Over the course of subsequent evolution, various blood cells, such as mast cells, diversified.
KyotoU / Yosuke Nagahata
In a stunning, albeit unwitting, rebuttal of creationist claims, a team of researchers at Kyoto University is due to publish, on 29 May 2026, the results of their investigation into the evolutionary history of animal blood cells in Proceedings of the National Academy of Sciences of the United States of America (PNAS). The paper, entitled "Animals have expanded the evolutionary legacy of unicellular ancestors in blood cells", is unlikely to please those creationists who keep assuring their dupes that biomedical scientists are about to abandon 'Darwinism' and adopt creationism instead.
It will also disappoint those who insist there is no evidence for the evolution of complex multicellular organisms from single-celled ancestors — what they like to caricature as the 'microbes-to-man hypothesis', as though humans, preferably modern Americans, were the preordained end-point of the entire history of life. That, of course, is creationist teleology masquerading as biology: the assumption that evolution must have been aiming at us because Bronze Age religion says humans are the central purpose of creation.
What the Kyoto University team found was not a sudden, magical appearance of blood cells, but a deep evolutionary continuity. They developed a new method for comparing gene-expression profiles across different animal cell lineages and species, and included unicellular organisms in the comparison in order to trace the possible origin of blood cells back to our single-celled animal ancestors.
Among human blood-cell lineages, macrophages showed the closest resemblance to unicellular organisms. This is hardly surprising, since macrophages still behave in a remarkably cell-autonomous way: they move through tissues, detect targets, engulf bacteria, clear dead cells and remove unwanted material — behaviour strongly reminiscent of free-living phagocytic cells.
The team then traced the gene FOS, commonly expressed in blood cells across animal species, back to a single-celled ancestor that lived about 700 million years ago, around the time when the first animals were evolving. The implication is that the earliest animal blood cells did not appear from nowhere. They arose when early multicellular animals repurposed genetic programmes inherited from their unicellular predecessors.
From there, the researchers were able to reconstruct a family tree of blood-cell lineages spanning roughly 700 million years. Their analysis suggests that early blood cells were macrophage-like, that mast cells later branched from that macrophage lineage, and that prototypic T cells and red blood cells subsequently branched from mast cells. Prototypic B cells, meanwhile, appear to have branched from the macrophage lineage after mast cells had already diverged.
In other words, the blood and immune cells circulating in our bodies today are not isolated, specially-created structures with no history. They are modified descendants of ancient cellular systems, inherited, repurposed and diversified during the evolution of animals from unicellular ancestors.
So, far from supporting the creationist claim that there is no evidence for the evolution of complex life from single-celled ancestors, the evidence is literally circulating in our blood. It is also circulating in the blood and immune systems of other animals, carrying with it a molecular and cellular legacy hundreds of millions of years older than the creation myths of the Bronze Age.
And, as usual, the Theory of Evolution provides the only coherent explanation for the observable facts. The research does not point to separate acts of creation, nor to a sudden magical appearance of blood cells fully formed and without ancestry. It shows descent with modification, inherited genetic programmes, divergence of cell lineages, and the repurposing of ancient biological mechanisms — exactly the pattern evolutionary theory predicts, and exactly the pattern creationism cannot explain without special pleading.
Sunday, 24 May 2026
Malevolent Design - Fungi That Turn Spiders Into 'Zombies'
Parasites are hard enough for creationists to force-fit into their predetermined belief that all things were created by an omnibenevolent god, short of resorting to the near-blasphemous claim that 'Sin' somehow gave a rival creator unfettered access to their god's supposedly perfect creation in order to corrupt and destroy it. That rather undermines the claim of perfection in the first place, because a perfect creation, by definition, ought not to be corruptible.
But even harder for creationists to explain are parasites which, judged by their own favourite pseudo-scientific slogans — 'complex specified information' and 'irreducible complexity' — appear exquisitely adapted not merely to parasitise a living organism, but to consume it from within and then use its body as a platform for producing more parasites. In Pensoft's own popular description, these are "zombie" fungi: araneopathogenic fungi that parasitise spiders, mummify them, and then grow spore-producing structures from their bodies.
For example, newly identified spider-attacking fungi have recently been reported in two papers, published respectively in IMA Fungus and MycoKeys. Together, they add to the growing picture of a hidden diversity of highly specialised fungal parasites adapted to exploit spiders in different habitats.
The first is a new species of Purpureocillium fungus, belonging to the Purpureocillium atypicola group: Purpureocillium atlanticum. It was discovered in Brazil's Atlantic Forest, where it infects trapdoor spiders hidden in their burrows in the forest floor. The fungus covers the spider in cotton-white mycelium and eventually sends a purple fruiting structure up from the spider's cephalothorax, allowing spores to be released above the burrow. This discovery also shows that Purpureocillium atypicola, originally discovered in Japan in 1897 and thought to be a single species, is actually a global complex of multiple species.
The second paper reports three new species of Gibellula fungi — Gibellula pseudopigmentosa, Gibellula pseudosolita, and Gibellula sinensis — discovered on spiders in China and Laos. These fungi erupt from spider bodies in stalked, branch-like structures, and the species were distinguished from one another by differences in their reproductive structures, spore-forming bodies and phylogenetic relationships.
Thursday, 21 May 2026
Refuting Creationism - Why T. Rex Evolved Tiny Arms - No Intelligence Involved
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]The publication in Proceedings of the Royal Society B is accompanied by a news release from UCL.
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.
Why meat-eating dinosaurs like T. rex evolved tiny arms
The 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.
Publication:
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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