Newly published research suggests that Allosaurus europaeus is not a valid taxon. A detailed study of Portuguese fossil material has led to the conclusion that the A. europaeus holotype (ML 415) represents Allosaurus fragilis.

The remains of large theropods ascribed to the Allosaurus genus have been found in Portugal. In 1988, fossils of a meat-eating dinosaur were discovered near the village of Andrés, (Leiria District, Portugal). Additional fossil finds from the coast at Praia de Vale Frades, (Lourinhã, Portugal) and a coal mine in the district of Leiria were assigned to Allosaurus. Subsequently, a European Allosaurus was erected in 2006 (Mateus et al). This dinosaur was named Allosaurus europaeus.  However, a detailed analysis of cranial material has led researchers to conclude that fossils attributed to A. europaeus should be bracketed as Allosaurus fragilis.

A life-size replica of an Allosaurus. The genus was first erected in 1877 (Marsh). Several species have been named but the validity of many of these species has been challenged. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The Demise of Allosaurus europaeus

Allosaurus fragilis was first described in the Upper Jurassic of Portugal in 1999 based on a set of postcranial remains collected at the Andrés fossil site in Pombal. The description of a second species, Allosaurus europaeus, based on elements from the back of the skull and a sequence of tail bones (ML 415) collected at Praia de Vale Frades in Lourinhã was controversial.  The scientists provide a detailed description of a new sample of skull fossil material.  These fossils from the village of Andrés are confidentially assigned to the Allosaurus genus.

In addition to the fossil study a comprehensive phylogenetic assessment of the Morrison Formation fossil record of Allosaurus was performed. The phylogenetic analysis indicates that there were only two valid Allosaurus species present in the Late Jurassic ecosystems of North America.  These species are Allosaurus fragilis and the recently erected Allosaurus jimmadseni.

To read Everything Dinosaur’s blog post about the establishment of A. jimmadseni as a separate species: A New Species of Allosaurus.

Manufacturers of prehistoric animal models were quick to introduce replicas of this new Allosaurus species.  Allosaurus jimmadseni was erected in 2020.  The American company Creative Beast Studios introduced an articulated replica of A. jimmadseni.

This figure has proved popular with collectors, especially collectors based in the USA.

To view the range of Beasts of the Mesozoic/Cenozoic figures: Beasts of the Mesozoic Figures.

The new Beasts of the Mesozoic Cyberzoic figure (A. jimmadseni) is one of the highlights of the latest customer newsletter. Shortly, after this new species was erected, new Allosaurus models came onto the market. Picture credit: Everything Dinosaur.

Referring Specimens to Allosaurus fragilis

The authors of the paper postulate that their analysis indicates that only two valid Allosaurus species were present in the Late Jurassic ecosystems of North America.  These two species are Allosaurus fragilis and Allosaurus jimmadseni.  The researchers provide an updated reference for Allosaurus classification.  The Portuguese specimens MNHN/UL.AND.#, ML 415, and MG 27804 are interpreted as belonging to A. fragilis.

This new research helps palaeontologists to better understand the evolution of theropods associated with the Lusitanian Basin.  The researchers consider that this study provides evidence of a close biogeographical relationship between North America and Europe during the Late Jurassic.

The scientific paper: “Cranial osteology of a new specimen of Allosaurus Marsh, 1877 (Theropoda: Allosauridae) from the Upper Jurassic of Portugal and a specimen-level phylogenetic analysis of Allosaurus” by Elisabete Malafaia, Pedro Dantas, Fernando Escaso, Pedro Mocho and Francisco Ortega published in the Zoological Journal of the Linnean Society.

The Everything Dinosaur website: Dinosaur Models.

Researchers have identified fossil tracks with skin impressions of early synapsids from the famous Bromacker fossil site in Thuringia (Germany).  These are the oldest skin impressions of early mammalian relatives known.  They provide unique insights into the evolution of scales and integumentary coverings within an Early Permian ecosystem.  The Bromacker quarry exposes 290-million-year-old deposits associated with the Tambach Formation. This rare site preserves exquisite, articulated fossils of a unique vertebrate fauna.  This quarry has been at the centre of a long research project, lasting decades led by the Museum für Naturkunde Berlin.

290-million-year-old skin impression fossils. Picture credit: Lorenzo Marchetti.

Picture credit: Lorenzo Marchetti

Studying the Trace Fossils of Early Synapsids

The fossil tracks were discovered over a century ago. These rare fossils were re-examined as part of the ongoing Bromacker research project.  This research project is run by the Federal Ministry of Research, Technology and Space.  The scientific paper has been published in the journal “Current Biology”.

Senior author of the study, Professor Jörg Fröbisch commented:

“It has been shown time and again that certain characteristics and traits of modern vertebrates, such as skin structure, lifestyle or social behaviour, appeared earlier in the course of evolutionary history than was initially assumed. The study once again demonstrates the globally unique significance of the fossil deposit at Bromacker and its enormous potential for future research.”

To read a blog post about a Dimetrodon fossil found at the Bromacker locality: Fossil Mystery is Solved.

Scales on the Underside, Legs and the Tail

One trackway preserved at the site is particularly illuminating. An impression preserved in the fine-grained Tambach sandstone reveals skin folds on the toes and various types of scales on the upper and lower legs.  There are also scale impressions from the ventral portion of the tail, the hip area and the abdomen.  The scientists have identified this as a resting track or evidence of a Permian vertebrate wallowing.

The arrangement and shape of the scale marks, sometimes diamond-shaped, rectangular, pentagonal to polygonal, sometimes overlapping like roof tiles, is reminiscent of the horny scales of membranous reptiles.

Evidence of Social Behaviour in Early Synapsids

A number of sandstone slabs preserve large numbers of tracks.  Several tracks are adjacent to each other, and some tracks are parallel.  The researchers suggest this is evidence of animals of the same species walking together.  The track producers, early synapsids such as Dimetrodon teutonis, probably rested, basked and cooled down together.  This suggests that these Permian animals demonstrated group behaviours, just like modern lizards, birds and mammals.

Everything Dinosaur acknowledges the assistance of a media release from the Museum für Naturkunde Berlin in the compilation of this article.

The scientific paper: “Early Permian synapsid impressions illuminate the origin of epidermal scales and aggregation behaviour” by Marchetti, L., Logghe, A., Buchwitz, M., and Fröbisch, J. published in Current Biology.

The award-winning Everything Dinosaur website: Dinosaur Models and Toys.

Newly published research in the journal “Nature” postulates that reptiles originated forty million years earlier than previously thought.  Fossil tracks (trace fossils) created by a small tetrapod with clawed feet, most probably a reptile, from the Snowy Plains Formation of Victoria, Taungurung Country significantly changes our view on the timeline of early amniote evolution.

The known fossil record of crown-group amniotes (the group that includes mammals, birds and reptiles), begins in the Late Carboniferous with sauropsid trace fossils and the body fossils of Hylonomus. The earliest body fossils of crown-group tetrapods are mid-Carboniferous, and the oldest trackways are Early Carboniferous.  Based on this evidence, it had been thought that the tetrapod crown group originated in the earliest Carboniferous (early Tournaisian), with the amniote crown group appearing in the early part of the Late Carboniferous.  This new fossil discovery challenges this view.

Flinders University Professor John Long and colleagues identified the fossilised tracks of an amniote with clawed feet.  The slab containing the fossil tracks is around 350 million years old.

Professor Long commented:

“Once we identified this, we realised this is the oldest evidence in the world of reptile-like animals walking around on land, and it pushes their evolution back by 35-to-40 million years older than the previous records in the Northern Hemisphere.”

Professor Long and his co-workers think the tracks were made by a small, lizard-like creature.

A reconstruction of an early amniote. The researchers believe the tracks were produced by an early reptile. This suggests that reptiles evolved some 40 million years earlier than previously thought. Picture credit: Martin Ambrozik.

Picture credit: Martin Ambrozik

Early Amniote Evolution

This discovery indicates that the first amniotes probably evolved in the Southern Hemisphere.  They may have evolved on the ancient supercontinent Gondwana.  Amniotes are vertebrates that undergo an embryonic developmental stage within an amnion. An amnion is a thin membrane that encloses the embryo and immerses the developing foetus in fluid. In simple terms, the amnion provides an environment in which the foetus can develop. In contrast, the eggs of amphibians do not have an amnion. They are dependent on a source of water in their environment in which to raise their young.

Professor Young added that the implications of this discovery for the early evolution of tetrapods are profound. All stem-tetrapod and stem-amniote lineages must have originated during the Devonian. It seems that tetrapod evolution proceeded much faster, and the Devonian tetrapod record is much less complete, than has been thought.

He explained:

“All stem-tetrapod and stem-amniote lineages must have originated during the Devonian period – but tetrapod evolution proceeded much faster, and the Devonian tetrapod record is much less complete than we have believed.”

Much remains uncertain regarding the evolution of early tetrapods and the rise of the amniotes. Scientists think that global warming may have led to the gradual dominance of the Reptilia and the demise of amphibians and their close relatives.

A dramatic change in climate may have aided the rise of the reptiles: Global Climate Change May Have Helped Reptile Evolution.

New Fossil Evidence

This new fossil evidence from Australia falsifies the previous, widely accepted timeline.  For Professor Long, his involvement with this amazing research goes back some forty-five years.  He did his PhD thesis on the fossils of the Mansfield district.  However, it was only recently after organising palaeontology field trips with Flinders University students that locals joined the hunt for fossils.

Two locals, Craig Eury and John Eason (co-authors of the study), found the slab covered in trackways.  At first, it was thought this trace fossil represented amphibian tracks.  However, a closer examination revealed that one track has a hooked claw coming off the digits, evidence for a reptile-like animal.

Searching for fossils in the Mansfield district of northern Victoria. Picture credit: Flinders University.

Picture credit: Flinders University

Crystal Clear Trackways

The trackways are preserved in astonishing detail. Dr Alice Clement (Flinders University and co-author), helped scan the fossil tracks to create digital models that could be analysed in detail.  Scientists from Uppsala University (Sweden) led by Professor Per Erik Ahlberg collaborated in this research. Digital heat maps were produced highlighting the depth and the topography of individual prints.

Dr Clement stated:

“We study rocks and fossils of the Carboniferous and Devonian age with specific interest to observe the very important fish-tetrapod transition. We’re trying to tease apart the details of how the bodies and lifestyles of these animals changed, as they moved from being fish that lived in water, to becoming tetrapods that moved about on land.”

Dr Aaron Camens (Flinders University), an expert in early tetrapod and amniote trackways explained that trackways record behaviour and tell scientists a lot about the animal’s locomotion.

He commented:

“A skeleton can tell us only so much about what an animal could do, but a trackway actually records its behaviour and tells us how this animal was moving.”

As Professor Long has been studying fossils from the Mansfield district since 1980, the team had a clear idea of the age of the rock deposits.  He has produced an extensive catalogue of fish fossils from the Mansfield district.  These fossils could then be compared with other fossil sites, with accurately dated rocks from around the world.  This location has produced some amazing fish fossils.  However, the quest had always been to find evidence of land animals (tetrapods).

Revising the Timeline of Early Amniote Evolution

The Mansfield district trace fossil slab dates from the Early Carboniferous (Tournaisian faunal stage).  Ironically, it was a comparison of fish fossils that permitted the team to calculate the age of the specimen to within ten million years.  This ground-breaking research has permitted the team to re-write the timeline of early amniote evolution. They conclude that these fossilised tracks show reptile-like animals appeared on Earth up to forty million years earlier than previously thought.

Revised timescale of early tetrapod evolution. Stratigraphic timescale representation of the Devonian and Carboniferous, showing the impact of the Snowy Plains Formation sauropsid tracks. The track record is shown as a pink rectangle, of double height to indicate possible age range. Picture credit: Long et al.

Picture credit: Long et al

Everything Dinosaur acknowledges the assistance of a media release from Flinders University in the compilation of this article.

The scientific paper: “Earliest amniote tracks recalibrate the timeline of tetrapod evolution” by John A. Long, Grzegorz Niedźwiedzki, Jillian Garvey, Alice M. Clement, Aaron B. Camens, Craig A. Eury, John Eason and Per E. Ahlberg published in the journal Nature.

The Everything Dinosaur website: Prehistoric Animal Models and Figures.

A new species of rinconsaurian titanosaur has been named based on fossils unearthed in northern Patagonia.  The dinosaur has been named Chadititan calvoi. The Rinconsauria clade comprises Late Cretaceous, relatively small and gracile Argentinian titanosaurs. Its composition remains disputed. Phylogenetic analyses reveal contrasting results depending on statistical parameters, but some academics have proposed as many as twenty taxa within this clade.

The fossil material, representing several individuals comes from outcrops of the Anacleto Formation. This formation is thought to have been laid down in the early to middle Campanian faunal stage of the Cretaceous.  The bedding plane associated with these fossils suggests that this dinosaur lived around seventy-eight million years ago.

Chadititan calvoi

The genus name is derived from the local dialect meaning “salt”. The type locality is an extensive salt flat. The species name honours the Argentine palaeontologist Jorge O. Calvo who first proposed the Rinconsauria clade.  Although known from fragmentary remains, palaeontologists have been able to estimate the size of this herbivore.  The partial femora (thigh bones), were compared to more complete Bonatitan (B. reigi) limb bones.  Chadititan is estimated to have been around seven metres long.

A scale drawing of the rinconsaurian titanosaur from northern Patagonia Chadititan calvoi. This dinosaur is estimated to have been about seven metres in length. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The Rinconsauria was erected in 2007.  The clade consists of slender relatively small titanosaurs with long limbs and modified pelvic girdles.  As far as we at Everything Dinosaur are aware, no osteoderms have been found in association with rinconsaurian fossils.  Dermal armour could have been absent in this clade of titanosaurs.

A Diverse Fossil Assemblage Dominated by Freshwater Turtles

The fossils were found at a location owned by the Marin family near General Roca city (Rio Negro province).  The authors of the scientific paper report a new assemblage of fossils representing a diverse biota.  The site could represent an oasis in what was an exceptionally arid environment.  Gastropods, lungfishes, freshwater turtles and crocodilian fossils have been found.

Turtle fossils are the most common vertebrate fossils present.  They represent over ninety percent of the recovered material.

The scientific paper: “New fossiliferous locality from the Anacleto Formation (Late Cretaceous, Campanian) from northern Patagonia, with the description of a new titanosaur” by Agnolín, Federico L.; Motta, Matías J.; Garcia Marsà, Jordi; Aranciaga-Rolando et al. Paper published – Revista del Museo Argentino de Ciencias Naturales.

The award-winning Everything Dinosaur website: Dinosaur and Prehistoric Animal Models.

The direct ancestor of the iconic Tyrannosaurus rex came from Asia. Newly published research lends weight to the theory that the direct ancestor of Tyrannosaurus rex dispersed into North America from Asia via an ancient land bridge. Fossils of T. rex are known from Canada and the USA. However, there is some evidence to suggest that this super-predator may also have roamed what is now Mexico.  The origins of this famous dinosaur, more specifically the Tyrannosaurini, have been hotly debated.

Did the ancestors of T. rex come from Asia or did its ancestors evolve in North America (southern Laramidia)?

The spectacular Titus the T. rex exhibit at Wollaton Hall. A newly published study (May 2025) supports the theory that the ancestors of the iconic Tyrannosaurus rex originated in Asia. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The Origins of the Iconic Tyrannosaurus rex

Previous studies had suggested that the ancestors of the iconic Tyrannosaurus rex migrated into North America from Asia. This theory was primarily based on the closer taxonomic relationship that T. rex has with Asian tyrannosaurids such as Zhuchengtyrannus and Tarbosaurus. Tyrannosaurus rex was more distantly related to Laramidian tyrannosaurids such as Daspletosaurus and Teratophoneus. So, based on this evidence, it was thought that the lineage of tyrannosaurs that were direct ancestors of the “Tyrant Lizard King” probably evolved in Asia.

Dalman et al in their scientific description of Tyrannosaurus mcraeensis (2024) proposed that the Tyrannosaurus genus evolved in southern Laramidia. Their theory was underpinned by the Late Campanian–Early Maastrichtian age of the T. mcraeensis holotype. However, doubt has been cast over the exact age of the holotype fossil material.

In this new study, a biogeographical analysis of the Tyrannosauridae family, particularly the tribe Tyrannosaurini suggests that tyrannosaurines diversified in the Late Campanian. This diversification supports the idea of a migration of ancestors of T. rex from Asia into North America.

To read Everything Dinosaur’s blog post about Tyrannosaurus mcraeensis: A New Tyrannosaurus Species is Described.

Tyrannosaurus Genus Likely Endemic to North America

The research team conclude that Tyrannosaurus is likely an endemic, North American genus.  The ancestor of the genus dispersed into North American biotas, where it would give rise to Tyrannosaurus. In addition, gigantism occurred numerous times within the Tyrannosauroidea. It was potentially driven by cooler or cooling climates. This study supports the idea that evolutionary changes within the Dinosauria of the Late Cretaceous was partly in response to climate change. The research illustrates the importance of using climate and ecological data to better understand dinosaurian evolution within wider global climatic shifts.

Shedding Light on the Enigmatic Megaraptoridae

The study also sheds light on the evolution of the enigmatic megaraptors.  The Megaraptoridae are a different family of theropod dinosaurs.  How closely related they were to the tyrannosaurs remains disputed.

Some megaraptors were giants.  They occupied the apex predator niche within many ecosystems.  For example, Maip macrothorax from the Late Cretaceous of Argentina may have measured in excess of ten metres long.  Whilst the Tyrannosaurini evolved massive skulls and powerful jaws to take down prey.  Megaraptorids such as Maip evolved in a different direction.  These predators had powerful forelimbs and grasping digits tipped with huge claws.

The new for 2025 CollectA Deluxe M. macrothorax figure shown in lateral view.

The picture (above) shows a 1:40 scale model of Maip macrothorax.  It is part of the CollectA Deluxe range of prehistoric animal figures.

To view the CollectA Deluxe range of models: CollectA Deluxe Prehistoric Animal Models.

Although the extremely fragmentary nature of the megaraptorid was a limiting factor in this research, the team postulate that the megaraptors most likely diverged from the tyrannosaurs around 170 million years ago in Asia.  The megaraptors spread south into what is now Australia, South America and Antarctica via Europe and Africa.

Megaraptorids evolved into the top predators in areas such as Patagonia and Australia, but elsewhere in the world, such as Asia they were replaced by tyrannosaurs.

The scientists would like to extend their modelling but to do so more early tyrannosaur and megaraptor fossils would be needed to make any analysis robust.

The scientific paper: “Rise of the king: Gondwanan origins and evolution of megaraptoran dinosaurs” by Cassius Morrison, Charlie Roger Scherer, Ezekiel V. O’Callaghan, Collin Layton, Colin Boisvert, Mauro Aranciaga Rolando, Leroy Durrant, Pedro Salas, Steven J. R. Allain and Samuel J. L. Gascoigne published by Royal Society Open Science.

For dinosaur toys and figures visit the Everything Dinosaur website: Everything Dinosaur.

Numerous bonebeds associated with horned dinosaurs are known.  For example, the remains of hundreds of Pachyrhinosaurus lakustai have been excavated from a single site in Alberta, Canada. Fossil sites such as this provide evidence that many horned dinosaurs lived in herds. However, until recently there was very little evidence to support the idea of a herd of Triceratops.  That the most famous horned dinosaur “three horned face” formed large, social groups.

To read about the excavation of a Pachyrhinosaurus skull from a bonebed: Remarkable Horned Dinosaur Skull Excavated from Bonebed.

Researchers from the Naturalis Biodiversity Centre (Leiden, Netherlands) have helped to change our view of Triceratops.  They have identified the remains of a least five individuals that lived and died together.  A decade of careful study of a dinosaur bonebed discovered in Wyoming has revealed that Triceratops too moved around in groups.

An artist’s reconstruction of a herd of Triceratops dinosaurs. Picture credit: Bart Bus.

Picture credit: Bart Bus

A Fossil Site Reviews a Herd of Triceratops

Ironically, the field team set out to find a T. rex. Nonetheless, what they found in the summer of 2013 has proved to be of much greater value to science than a single theropod specimen.  The research work at the Lance Formation (Maastrichtian) exposures has revealed a large bonebed of Triceratops (T. horridus). Over the last decade, some twelve hundred individual bones have been excavated from the site. Importantly, the abundant postcranial material displays features of both subadult and adults. This fossil locality can shed new light on the ontogeny and possible gregarious behaviour of this iconic dinosaur.

Field team member Jimmy de Rooij digging up a Triceratops fossil. Picture credit: Marten van Dijl (Naturalis Biodiversity Centre).

Picture credit: Marten van Dijl (Naturalis Biodiversity Centre)

A team of palaeontologists and volunteers spent many summers at the site mapping and extracting the precious bones.  One of the researchers Jimmy de Rooij hopes to receive a PhD from Utrecht University for his work on this remarkable bonebed.

He commented:

“The material is of very god quality.  This enabled us to show that these Triceratops grew really slowly for instance.”

It is thought that all these dinosaurs perished together, perhaps mired in a swamp.  The fossils are all contained in a thin layer, without the bones of other species present.

Jimmy de Rooij holding a Triceratops horn. Picture credit: Naturalis Biodiversity Centre.

Picture credit: Naturalis Biodiversity Centre

Publishing Scientific Papers and Opening an Exhibition

A scientific paper outlining the fossil discoveries and postulating that this was strong evidence to indicate that Triceratops horridus was gregarious was published in 2019.  However, the research into this treasure trove of horned dinosaur bones continues today.  An exhibition telling the story of the Wyoming bonebed and its significance to palaeontology has opened at the Naturalis Biodiversity Centre.

A sixth Triceratops specimen on display at the Naturalis Biodiversity Centre. Picture credit: Naturalis Biodiversity Centre.

Picture credit: Naturalis Biodiversity Centre

Study of the physical and chemical properties of hundreds of individual bones indicates that Triceratops migrated.  All five Triceratops specimens exhibit the same characteristics.  In other words, this iconic dinosaur species moved around in groups, at least for part of the time.  Visitors to Wyoming at the end of the Cretaceous might have spotted a herd of Triceratops!

A Herd of Triceratops horridus

The CollectA T. horridus ceratopsian figure in right lateral view. This Triceratops dinosaur model has an articulated lower jaw. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The image (above) shows a 1:40 scale model of Triceratops horridus.  This is the biggest Triceratops species described to date and one of the largest ceratopsids known to science.  The replica is from the CollectA Deluxe range of scale prehistoric animal figures.

To view the CollectA Deluxe range: CollectA Deluxe Age of Dinosaurs Models.

The discovery of what potentially could be a small herd of Triceratops poses some intriguingly questions.  For example, did these herbivores indulge in complex social behaviours?

Professor Anne Schulp (Naturalis Biodiversity Centre/Utrecht University), and De Rooij’s PhD supervisor proudly stated:

“Naturalis, the national natural history museum of the Netherlands, now has the biggest Triceratops find in the world, and Utrecht University has the first Dr Triceratops in the Netherlands. De Rooij’s work didn’t just result in research papers, but also in an exhibition about his findings.”

Mike from Everything Dinosaur commented:

“The exhibition will give dinosaur fans young and old the chance to learn more about Triceratops.  Indeed, visitors will be able to see the five fossil Triceratops specimens together some sixty-seven million years after they lived and died together.”

Visit the Everything Dinosaur website, which is award-winning and customer-friendly: Dinosaur Models and Prehistoric Animal Figures.

Everything Dinosaur acknowledges the assistance of a media release from the Naturalis Biodiversity Centre in the compilation of this article.

Phytosaurs were a geographically widespread group of semiaquatic reptiles that thrived in the Late Triassic. Everything Dinosaur team members look at the remarkable phytosaur Colossosuchus techniensis and other related genera.

The phylogenetic position of the phytosaurs remains disputed. This is in part as little is known about their ancestral forms. For example, some scientists classify phytosaurs as members of the Archosauria, uniting them in the same clade as crocodiles, pterosaurs, dinosaurs and birds. However, other researchers, notably the American palaeontologist Sterling Nesbitt does not define the Phytosauria as archosaurs, but as close relatives to the Archosauria (Archosauriformes).

Often depicted with a sprawling gait, a trackway assigned to a phytosaur (Apatopus) indicates that these reptiles adopted a “high walk” gait.  They had an erect stance, albeit with a tail drag, and a parasagittal gait, much as crocodiles do today.

Phytosaurs Resembled Extant Crocodilians

These animals superficially resembled crocodilians, although they were not closely related to modern crocodiles. This is an example of convergent evolution.  Convergent evolution is the process through which distantly related or unrelated organisms evolve similar characteristics or adaptations in response to similar environmental pressures.  For instance, most phytosaurs were probably aquatic ambush predators.  They occupied an environmental niche in ancient ecosystems similar to the niche occupied by extant crocodilians.

A museum exhibit featuring a typical phytosaur. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Characteristics of Phytosaurs

Although superficially resembling crocodiles there were notable differences.  For example, the nostrils of phytosaurs were located high up on the skull, almost between the eyes. The nostrils were located atop a dome-like structure towards the posterior of the snout. In crocodilians, the nostrils are located at the tip of their long snouts.

The location of the nostrils in a phytosaur. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

In addition, phytosaurs lacked the bony secondary palate found in crocodilians.  Although, they probably possessed a fleshy secondary palate that enabled them to breathe whilst they had water in their mouths.  Unfortunately, the presumed presence of a fleshy palate is not confirmed in the fossil record, probably due to this structure’s poor preservation potential.

The arrangement of dermal armour was probably different too. Phytosaurs probably had a paired row of armoured scutes running down their backs. In contrast, crocodilians have multiple rows of scutes.

The manus (hand) of these reptiles such as the phytosaur Colossosuchus techniensis consisted of five digits.

A description of the phytosaur manus:

• The manus is short and rounded with digit III being longest.
• Digits II and IV are approximately the same length.
• Moreover, digit V is the smallest digit. Digit I (pollex) is short but robust.
• Claws are present on digits I to IV.
• The largest claws being located on digit I and II.

A description of the phytosaur pes:

• The pes had five digits.
• Digit I was short and quite robust.
• Digits II, III and IV were long and slender.
• Digit IV was the longest.
• It is believed that all the digits had claws.
• Digit V was much reduced and the shortest digit. It did have a small claw.

How Big were the Largest Phytosaurs?

Scientists remain uncertain over the size of the largest taxa.  Some phytosaurs may have been bigger than the largest living crocodilian the Saltwater crocodile (Crocodylus porosus) which rarely exceeds six metres in length. For example, Rutiodon carolinensis from the southeastern United States is thought to have measured about eight metres long.  It is known from numerous fossil specimens including skull material. The largest skull measures seventy-seven cm in length.

Furthermore, Smilosuchus gregorii is thought to have reached a length of around eight metres.  Some body length estimates for this species exceed twelve metres. However, these estimates are based on highly fragmentary specimens. The recently described Indian phytosaur Colossosuchus techniensis is also estimated to have reached a length of around eight metres.

The 2023 scientific paper describing the phytosaur Colossosuchus techniensis:

“A giant phytosaur (Diapsida, Archosauria) from the Upper Triassic of India with new insights on phytosaur migration, endemism and extinction” by Debajit Datta and Sanghamitra Ray published in Papers in Palaeontology.

Mike from Everything Dinosaur commented:

“Intriguingly, there are numerous examples of at least two phytosaur species being coeval.  One species is often narrow-snouted [Dolichorostral] with teeth that are very similar.  The second species often has a much more robust snout [Brachyrostral] with differently shaped teeth.  Often the robust snouted forms have long fangs at the end of their jaws.  This suggests that these two phytosaurs evolved to take advantage of different food resources although they shared the same environment. Niche partitioning seems to have taken place quite frequently within the Phytosauria.”

Visit the Everything Dinosaur website: Prehistoric Animal Figures.

Palaeontologists explain this niche partitioning phenomena by suggesting that the ancestral phytosaur species specialised in eating different things.  They eventually diverged into two closely related but different species. It is remarkable that this evolutionary pattern is repeated so often within the Phytosauria fossil record.

Time to catch up on this year’s dinosaur discoveries.  For instance, a new species of North African carcharodontosaurid was described recently.  The fragmentary fossil material representing Tameryraptor markgrafi was excavated during the expedition to Egypt led by the famous German palaeontologist Ernst Stromer von Reichenbach.  The naming of this new dinosaur (Kellermann, Cuesta and Rauhut), demonstrates that the theropods of the Bahariya Oasis and the Moroccan Kem Kem Group are not as closely related as previously thought.  Researchers have stated that the proposed faunal similarities between these two strata need further examination.

Tameryraptor markgrafi

The partial skeleton from the Egyptian Bahariya Oasis, found in April 1914, consisted of elements from the skull, a partial dorsal vertebra, upper limb ones, the proximal end of the pubis and part of a caudal vertebra.  It was described by Stromer in 1931.  The material was first assigned to the species Megalosaurus saharicus, which had been described from isolated teeth found in geologically older rocks in Algeria. Unfortunately, almost all of the material from the Bahariya Oasis, including these fossils was destroyed during a bombing raid in World War II.

A detailed reassessment of the available information on the Egyptian carcharodontosaurid, including a previously undescribed photograph of the exhibited specimen, revealed that it differed from the Moroccan Carcharodontosaurus saharicus in several ways.  It also possessed a horn-like rugosity on the nasal bone.  These unique characteristics permitted the research team to confidently reassign these fossils, removing them from the C. saharicus taxon and allowing the naming of a new species of North African theropod.

A photograph of the holotype fossil material (SNSB-BSPG 1922 X46) on display. This photograph was taken prior to April 1944. Picture credit: Kellermann et al.

Picture credit: Kellermann et al

The fossils were discovered around two kilometres from Ain Gedid on the Western foot of the Gebel Harra in basal layers of hardened, gypsum-free marl.  The fossil material is thought to be around ninety-five million years old (Cenomanian faunal stage of the Late Cretaceous).

Based on the photographic evidence and a single endocast of the skull that remains, palaeontologists have estimated that Tameryraptor was around ten metres long.

An illustration of the large carcharodontosaurid from the Bahariya Formation (Egypt). It has been named Tameryraptor markgrafi. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The Etymology of Tameryraptor

The genus name is derived from one of the more informal names for Egypt (ta-mery), which means beloved land and the Latin word for thief (raptor).  The species name honours Austrian fossil collector Richard Markgraf, who discovered most of the dinosaur remains described by Ernst Stromer von Reichenbach.

The scientific paper: “Re-evaluation of the Bahariya Formation carcharodontosaurid (Dinosauria: Theropoda) and its implications for allosauroid phylogeny” by Maximillian Kellerman, Elena Cuesta and Oliver W. M. Rauhut published in PLOS One.

The award-winning Everything Dinosaur website: Dinosaur and Prehistoric Animal Models.

An American biotech firm has claimed that their gene editing techniques has led to dire wolf de-extinction.  The front cover of the prestigious “Time” magazine features a remarkable photograph of an oversized wolf staring back at the camera.  It is a powerful image, a testament to advances in gene manipulation and editing undertaken by Colossal Biosciences. However, the young wolves named Romulus, Remus along with a younger female named Khaleesi are not Aenocyon dirus.

A photograph of the two males (Romulus and Remus) aged three months. These canids born 10/1/2024 Picture credit: Colossal Biosciences.

Picture credit: Colossal Biosciences (media release received 08/04/2025)

Dire Wolf De-extinction

Early this month, Colossal Biosciences announced the rebirth of the once extinct dire wolf (A. dirus). It was claimed this was the world’s first successfully de-extincted animal.

Commenting on the company’s work CEO Ben Lamm stated:

” I could not be more proud of the team.  This massive milestone is the first of many coming examples demonstrating that our end-to-end de-extinction technology stack works.”

He added:

“Our team took DNA from a 13,000-year-old tooth and a 72,000-year-old skull and made healthy dire wolf puppies. It was once said, any sufficiently advanced technology is indistinguishable from magic. Today, our team gets to unveil some of the magic they are working on and its broader impact on conservation.”

Dr Beth Shapiro (Chief Science Officer) explained that the company’s novel approach to improving an ancient genome in the absence of more complete material set a new standard in gene management.

Team members at Everything Dinosaur first came across Dr Shapiro’s research a decade ago.  Dr Shapiro had written an intriguing book outlining how modern science and gene manipulation could result in the de-extinction of the Woolly Mammoth.

Everything Dinosaur’s review of “How to Clone a Mammoth”: How to Clone a Mammoth (De-extinction).

Dr Shapiro commented:

“Together with improved approaches to recover ancient DNA, these computational advances allowed us to resolve the evolutionary history of dire wolves and establish the genomic foundation for de-extinction – specifically for selecting with confidence dire wolf specific genetic variants that establish our targets for gene editing.”

Challenging the De-extinction of Aenocyon dirus

Whilst the birth of these canids represents a considerable achievement.  Many scientists have cast doubts on the claim that these three animals represent a revival of a long extinct taxon.  The idea that the dire wolf has been resurrected has been challenged.  Extinction remains permanent.  Instead, the scientists at Colossal Biosciences have used synthetic biology technologies to identify in ancient DNA from dire wolf remains key segments of the genetic code that could be manipulated to produce a modified grey wolf (Canis lupus).

In essence, what has been produced is a grey wolf but with some dire wolf-like traits, such as the larger skull and white fur.

The Rebor dire wolf/fantasy figure with its product packaging. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The picture (above) shows a replica of a dire wolf.  It is part of the Rebor range of models and figures.  There has been a renewed interest in dire wolves since they featured in the hit fantasy television series “Game of Thrones”.

To view the range of Rebor figures in stock: Rebor Figures and Models.

Implications for Conservation

The research may have important applications in helping to maintain healthy populations of highly endangered animals. For example, Colossal Biosciences have also produced two litters of red wolves from three different genetic founder lines. The red wolf (Canis rufus) is the most critically endangered wolf in the world.  These litters include one adolescent female red wolf (Hope) and three male red wolf puppies (Blaze, Cinder, and Ash).

Mike from Everything Dinosaur said:

“They are beautiful animals, and they represent an example of the huge advances being made in biosciences.  However, numerous academics and scientists have stated that they are not dire wolves but essentially a modified grey wolf that has some physical traits that represent a different species”.

Colossal Biosciences are continuing to research the de-extinction of other iconic animals.  For example, they are examining the possibility of resurrecting the Thylacine.  In addition, CEO Ben Lamm has claimed that the first Woolly Mammoth calves produced using this type of technology might be born within three years.

Resurrecting the Woolly Mammoth: The Return of the Woolly Mammoth.

The award-winning Everything Dinosaur website: Everything Dinosaur Models.

Scientists have named a unique, two-fingered therizinosaur species.  The fossils of Duonychus tsogtbaatari come from the Upper Cretaceous Bayanshiree Formation of the Gobi Desert (Mongolia).  This is the first time that a reduction of the digits on the manus has been recorded within the Therizinosauridae family.  All other therizinosaurs possessed three fingers on each hand.  Moreover, each finger ended in a curved claw.  Some of the claws of therizinosaurs were huge.  For example, one of the largest, Therizinosaurus cheloniformis had finger claws over a metre in length.

A life reconstruction of Duonychus tsogtbaatari. This dinosaur had two fingers on each hand. Although the fossils from which this new species has been described represent a subadult. Scientists have calculated that It weighed approximately 260 kilograms and was around three metres in length. Picture credit: Tim Bollinger.

Picture credit: Tim Bollinger

Duonychus tsogtbaatari

Duonychus (pronounced due-oh-ny-kus) translates from the Greek as “two claws”.  The species name honours the Mongolian palaeontologist Khishigjav Tsogtbaatar.  The discovery of this therizinosaur is doubly unique.  One of the sheaths on a fossil claw (digit I) has been preserved.  The sheath made from the protein keratin (same as our hair and fingernails), reveals that the claw was much longer than the underlying bone.  It was forty percent longer than the claw’s bony core.  It is the largest claw of its kind found fully preserved in this way.  The total claw length has been estimated at around thirty centimetres.

Duonychus tsogtbaatari was not carnivorous.  These long claws were probably not used to attack other dinosaurs.  Although, they could have had a defensive function or have been used in intraspecific combat.  The researchers studying the fossil material believe the long, curved claws and the ability of Duonychus to flex them would have helped this animal to grasp vegetation.

Duonychus tsogtbaatari data card. Picture credit: Tim Bollinger.

Picture credit: Tim Bollinger

Digit Reduction in Theropod Dinosaurs

The most famous two-fingered theropod dinosaur is Tyrannosaurus rex.  Duonychus is not closely related to T. rex.  However, both these dinosaurs evolved from ancestors that had three digits on each hand.  So, why did some theropod dinosaurs lose digits?  It is likely that the outer fingers of the hand became less useful and so they were gradually reduced over the time.  An evolutionary pathway led to the outer fingers becoming redundant, then vestigial, before finally disappearing altogether. Alternatively, digits I and II became increasingly dominant and thus enlarged.  This led to the eventual reduction and elimination of digit III.

Intriguingly, the hand claws of Duonychus were highly curved.  The researchers conclude that the extremely curved claws were adaptations to help this animal to “hook” branches and pull them within easy reach.  In essence, the reduction of digits was an evolutionary adaptation towards more efficient feeding.

Potential Niche Partitioning?

The sediments of the Bayanshiree Formation preserve a diverse dinosaur biota.  For example, there were at least three other therizinosaurs that were likely coeval with Duonychus.  All the other Bayanshiree Formation therizinosaurs described to date had three fingers on each hand.  With so many therizinosaurs in the same environment, it is possible that Duonychus evolved reduced digits to permit it to feed on different types of vegetation.  The reduced fingers could represent evidence of niche partitioning within the Therizinosauridae associated with these strata.

The four therizinosaurs described from the Bayanshiree Formation to date:

• Segnosaurus (S. galbinensis) named in 1979. One of the largest therizinosaurs known with a length of around seven metres.
• Erlikosaurus (E. andrewsi) named in 1980.  Measuring around three and half metres in length it had a robust beak suggesting a diet of mainly vegetation.
• Enigmosaurus (E. mongoliensis) named in 1983.  Some scientists consider Enigmosaurus a junior synonym of Erlikosaurus.  Although, the discovery of Duonychus lends support to the idea that several different types of therizinosaur were present.
• Duonychus (D. tsogtbaatari) named in 2025.  The first didactyl therizinosaur, possessing only two manual digits. In addition, the keratinous sheath on digit I provides a rare insight into theropod claw structure.

It is also worth noting that several other potential therizinosaur fossil specimens have been excavated from the Bayanshiree Formation.  These have yet to be formally named and described.

Our thanks to Tim Bollinger for permission to use his Duonychus illustrations in the compilation of this article.

Take a look at Tim Bollinger’s work under the moniker UnexpectedDinoLesson:

Instagram – @unexpecteddinolesson
Facebook – @UnexpectedDinoLesson
X (Twitter) – @Dino_Lesson

The scientific paper: “Didactyl therizinosaur with a preserved keratinous claw from the Late Cretaceous of Mongolia” by Yoshitsugu Kobayashi, Darla K. Zelenitsky, Anthony R. Fiorillo and Tsogtbaatar Chinzorig published in the journey iScience.