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/Palaeontological articles

Articles, features and information which have slightly more scientific content with an emphasis on palaeontology, such as updates on academic papers, published papers etc.

16 01, 2023

Carboniferous Chimaeras were Suction Feeders

By | January 16th, 2023|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Carboniferous chimaeras were suction feeders unlike their modern relatives such as the rat fish which are durophagous (feed on hard-shelled prey such as crabs, snails and molluscs). That is the conclusion of new research published this week in the academic journal The Proceedings of the National Academy of Sciences (PNAS).

An Exceptional Three-dimensional Fossil

The research led by the Muséum national d’histoire naturelle (MNHN) located in Paris, and the University of Birmingham has shown that an ancient relative of chimaeras, jawed vertebrates that are related to cartilaginous fishes (sharks and rays), fed by sucking in prey animals underwater.

An exceptional three-dimensional fossil of an ancient chimaera (Iniopera genus), has revealed new clues about the diversity of these creatures during the Carboniferous period.

Carboniferous chimaeras
The three-dimensional cast of the Carboniferous chimaera fossil (Iniopera) which helped the researchers to determine feeding strategy. Picture credit: University of Birmingham.

Carboniferous Chimaera

The fossil, from a genus called Iniopera, is the only suction feeder to be identified among chimaeras, and quite different from living chimaeras, which generally feed by crushing molluscs and other hard-shelled prey between their teeth.

Chimaeriformes are an ancient order of cartilaginous fish (Chondrichthyes) that are thought to have evolved in the Devonian. Most extant species are found at depths greater than two hundred metres, and some chimaera fish are restricted to extremely deep water (Bathypelagic Zone).

Most fossil and extant chimaeras are quite small, very few specimens exceed one metre in length. However, other prehistoric, cartilaginous fish that were distantly related to Iniopera grew much larger. For example, the Permian genus Helicoprion with its bizarre tooth-whorl jaw, which has been estimated to have grown to around eight metres in length.

Helicoprion scale drawing
As Everything Dinosaur prepares for the arrival of Haylee the Helicoprion model from PNSO a scale drawing of this Permian fish has been commissioned. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Although models of prehistoric fish from the Chondrichthyes Class are rare, PNSO have included two prehistoric shark figures (O. megalodon and Cretoxyrhina) and a replica of Helicoprion.

To view the PNSO prehistoric animal model range in stock at Everything Dinosaur: PNSO Age of Dinosaurs Models and Figures.

Identifying a Suction Feeder

Commenting on the significance of this study, lead researcher Dr Richard Dearden (University of Birmingham) stated:

“Being able to identify Iniopera as a suction feeder sheds light on the diverse role of chimaeras in these early ecosystems. In particular, it suggests that in their early evolutionary history, some chimaeras were inhabiting ecological niches that are now monopolised by ray finned fishes – a far cry from their modern life as specialised shell-crushers.”

The cartilage skeleton of these fish are rarely fossilised and the Chondrichthyes tend to be underrepresented in the fossil record. The skeletons that are preserved tend to be crushed flat and distorted so interpreting them is notoriously difficult. However, by studying the tooth shapes and diverse body plans, palaeontologists were already aware that extinct forms were far more varied than their living counterparts.

3-D Imaging Techniques

Using advanced 3-D imaging techniques, the researchers reconstructed the head, shoulder and throat skeleton of the Iniopera fossil. They then estimated the location of major muscles and found the anatomy was poorly suited to durophagous feeding. Instead, the researchers believe the animal was more likely to have used the muscle arrangement to expand the throat to take in water and a forward-pointing mouth to orient towards prey.

Suction feeding is a technique used by many animals that live underwater. It involves generating low pressures in the throat to pull in water and prey. To do this effectively, the animal needs to be able to rapidly expand its throat, and point its mouth forward towards prey items. Numerous different aquatic jawed vertebrates, such as ray-finned fishes and some turtles have evolved specialised anatomies to help them feed in this manner more effectively.

The suction feeding theory is also supported by fossilised Chimaeriformes that have preserved stomach contents. Small arthropods have been found in association with the body cavity of several specimens and their relatively entire state suggests suction feeding as the method of prey capture.

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

5 01, 2023

The Skin of Diplodocus

By | January 5th, 2023|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

The debate over whether theropod dinosaurs were feathered, scaly or perhaps a combination of both continues. In contrast, the integumentary covering of sauropod dinosaurs has largely remained uncertain due to the very limited fossil evidence. However, at one remarkable location in Montana, patches of fossilised Diplodocus skin have been preserved and an analysis indicates that these long-necked dinosaurs were most likely covered in scales, but surprisingly their skin scales were not uniform. A range of scale shapes are indicated, all of them relatively small, but ovoid, rectangular, polygonal, domed scales and irregular (globular) scales have been identified.

The texture on the neck and shoulders of the Schleich Brachiosaurus dinosaur model.
The scales found on a replica of the sauropod Brachiosaurus (Schleich) research suggests that diplodocids were covered in a variety of scales. Globular and domed scales have been identified along with ovoid and more uniform polygonal scales. Picture credit: Everything Dinosaur.

A Research Paper

In a scientific paper published in the on-line, open-access journal PeerJ (April 2021), written by Tess Gallagher (currently a Masters student at Bristol University), in collaboration with colleagues from, what was known at the time as the Bighorn Basin Paleontological Institute, descriptions were provided of some patches of skin associated with juvenile Diplodocus fossils.

The fossil material comes from a single location known as the Mother’s Day Quarry, located in the Bighorn Basin, (Montana). The site was originally discovered in the 1990s and the Upper Jurassic deposits have yielded over two thousand Diplodocus fossil bones. Surprisingly, given the concentration of sauropod material found, very few other fossils have been discovered in this quarry. To date, some theropod teeth (allosaurid) are known plus one potential theropod footprint, preserved in association with the skin and a single invertebrate specimen.

It has been suggested that a herd of young Diplodocus dinosaurs died from lack of water at a dried up watering hole. Their bodies remained on the surface for some time and became desiccated. A flash flood occurred and swept the corpses downstream and these accumulated bodies were rapidly buried.

The dinosaur skin, having been bleached and dried out on the surface, once rapidly buried has an increased chance of becoming fossilised. Recently published research (October 2022), from Drumheller et al suggests that “mummified” skin might be more common in the fossil record than previously thought.

To read Everything Dinosaur’s blog post about this phenomenon: Dinosaur Mummies an Alternative Fossil Pathway.

Fossilised Diplodocus Skin

Although only a small portion of skin has been identified to date and the scientists remain uncertain as to which part of the body the skin patches covered, analysis has revealed a remarkably diverse quantity of scales. The team conclude that considering how diverse the scale shapes are in such a small area of skin, it is possible that these distinct scale shapes may represent a transition on the body from one region to another, perhaps from the abdomen to the dorsal side, or abdomen to the shoulder.

Fossilised Diplodocus skin.
Photograph of specimen number MDS-2019-028 showing patches of diplodocid skin preserved between two rib bones. The black arrow indicates north. Picture credit: Gallagher, Poole and Schein.

At least six different types of Diplodocus scale have been identified, suggesting that the skin of these sauropod dinosaurs was complex. In addition, a further study presented at the recent annual meeting of the Society of Vertebrate Paleontology in Canada, provided a fresh perspective on the specialised skin of these sauropods.

Analysis of the scales using a high-powered microscope revealed that they had unusually large pores. It has been proposed that these large pores helped increase the surface area of this huge dinosaur. The greater the surface area of the skin the more assistance it would have been in helping to keep Diplodocus cool. Elephants have wrinkled skin, this increases the skin’s surface area which helps to minimise the impact of the “square-cube law” in relation to overheating.

“Square-cube” Law

The larger the volume of an animal, the smaller the overall surface area of the skin in contact with the air and this makes dissipating heat difficult for large animals. Just as elephants help to resolve issues with overheating with their wrinkled skin, the large pores associated with the Diplodocus skin had a similar effect.

Fossilised Diplodocus skin (line drawing).
Simplified line drawing showing the distribution of different scale shapes on the specimen number MDS-2019-028. The black arrow shows north. Drawing by T. Gallagher. Picture credit: Gallagher, Poole and Schein.

The scientific paper: “Evidence of integumentary scale diversity in the late Jurassic Sauropod Diplodocus sp. from the Mother’s Day Quarry, Montana” by Tess Gallagher, Jason Poole and Jason P. Schein published in PeerJ.

4 01, 2023

Plant-eating Dinosaurs Ate Plants Differently

By | January 4th, 2023|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles|0 Comments

Newly published research demonstrates that plant-eating, ornithischian dinosaurs had different ways of tackling the plants that made up their diet. Scans of the skulls of five, herbivorous dinosaurs, all members of the bird-hipped group (Ornithischia), were used to create three-dimensional models of the skull, teeth and jaws. These computer models were then subjected to a series of stress tests measuring the jaw muscles and calculating bite forces to help palaeontologists understand how different feeding strategies evolved in the Dinosauria.

Life-size Psittacosaurus replica.
A model of the dinosaur called Psittacosaurus. A skull model of this Early Cretaceous dinosaur was tested to determine the impact of bite force stresses on the bones. This data provided the scientists with information on different feeding strategies within the Ornithischia. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Plant-eating Dinosaurs

It is thought that the very earliest dinosaurs were carnivorous. However, quite early in their evolutionary history, the Dinosauria diversified and new forms with different diets (herbivory and omnivory) evolved.

In a recently published study (December 2022), analysis of dinosaur tooth shape suggested that the ancestors of the huge, herbivorous sauropods were meat-eaters, whilst many groups of plant-eating, ornithischian dinosaurs were ancestrally omnivorous.

To read Everything Dinosaur’s blog post about this research: Tooth Shape Helps Shape Dinosaur Diet.

Earliest Representatives of Major Ornithischian Groups

The skull and jaw muscles of some of the earliest representatives of major families within the Ornithischia were studied namely:

  • Heterodontosaurus – Heterodontosauridae family from the Early Jurassic.
  • Lesothosaurus – A basal ornithischian known from the Early Jurassic, possibly part of the early ornithopod lineage or perhaps an ancestor of armoured dinosaurs (Thyreophora).
  • Scelidosaurus – An early member of the Thyreophora (Early Jurassic).
  • Hypsilophodon – Regarded as a basal ornithopod (Early Cretaceous).
  • Psittacosaurus – A basal member of the Marginocephalia clade (Early Cretaceous) which includes horned dinosaurs (ceratopsids) and the bone-headed dinosaurs (pachycephalosaurs).

Writing in the academic journal “Current Biology”, the research team, which included scientists from the University of Birmingham, the London Natural History Museum and Bristol University, conclude that these herbivorous dinosaurs evolved very different ways of tackling their diet of vegetation.

Plant-eating dinosaurs ate plants differently.
Different feeding strategies in ornithischian dinosaurs. Computerised tomography was used to create models of skulls and these models were subjected to bite force stress tests to assess how these dinosaurs fed. Picture credit: David Button.

Skull Morphology and Jaw Musculature Reveal Different Feeding Strategies

Using computer models and finite element analysis to assess the impact of stress on the skull and bite forces the team discovered that Heterodontosaurus had disproportionately large jaw muscles in relation to the size of its skull. It had a powerful bite. As it was able to generate a higher bite force this would have helped it to consume tough plants. Scelidosaurus had a similar bite force, but relatively smaller jaw muscles compared to the size of its skull. Hypsilophodon, in contrast, had proportionately smaller jaw muscles, it could bite more efficiently but with less force.

Co-author of the study, Dr Stephan Lautenschlager (University of Birmingham), commented:

“We discovered that each dinosaur tackled the problems posed by a plant-based diet by adopting very different eating techniques. Some compensated for low eating performance through their sheer size, whilst others developed bigger jaw muscles, increased jaw system efficiency, or combined these approaches. Although these animals looked very similar, their individual solutions to the same problems illustrates the unpredictable nature of evolution.”

Compared to Birds and Crocodilians

The jaw muscles were reconstructed on the model skulls using extant archosaurs as templates (birds and crocodilians). Finite element analysis was then conducted to determine the potential bite force of each dinosaur. Finite element analysis involved dividing the skull into thousands of individual parts (called elements). The bite force these muscles can generate is calculated based on their size and arrangement.

Heat maps showed the different stress levels generated throughout each skull as the biting motion was simulated. The results revealed that although all of these dinosaurs were eating plants, each type of dinosaur had a different way of doing it.

Professor Paul Barrett (London Natural History Museum), explained that it was essential for palaeontologists to understand how dinosaurs evolved to feed on plants in so many ways. This diversity in feeding strategies helps to explain how these animals came to be the dominant primary consumers in terrestrial food chains for millions of years.

Lead author of the study, Dr David Button (University of Bristol) explained:

“When we compared the functional performance of the skull and teeth of these plant-eating dinosaurs, we found significant differences in the relative sizes of the jaw muscles, bite forces and jaw strength between them. This showed that these dinosaurs, although looking somewhat similar, had evolved very different ways to tackle a diet of plants.”

Scelidosaurus
An illustration of the Early Jurassic armoured dinosaur Scelidosaurus. A study of this dinosaur’s skull morphology and jaw muscles has led to palaeontologists gaining a new perspective on the feeding strategies of early armoured dinosaurs. Picture credit: Everything Dinosaur.

Dr Button went onto add:

“This research helps us understand how animals evolve to occupy new ecological niches. It shows that even similar animals adopting similar diets won’t always evolve the same characteristics. This highlights how innovative and unpredictable evolution can be.”

These differences in feeding strategy identified in this research demonstrates that each of these types of ornithischian dinosaur evolved a distinct solution to feeding on plants.

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

The scientific paper: “Multiple pathways to herbivory underpinned deep divergences in ornithischian evolution” by David J. Button, Laura B. Porro, Stephan Lautenschlager, Marc E. H. Jones and Paul M. Barrett published in Current Biology.

2 01, 2023

Sauropod Dinosaurs Did Not Have Supersonic Tails

By | January 2nd, 2023|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

A recent study published in the academic journal “Scientific Reports” refutes the idea that some long-necked herbivores had supersonic sauropod tails. The controversial idea that some dinosaurs could lash their tails like a whip creating a supersonic crack as the tail travelled faster than the speed of sound has been refuted in newly published research. Instead, the researchers suggest that the tail of diplodocids such as Apatosaurus, Brontosaurus and Diplodocus could still play a role in defence, producing a painful blow to deter an attacker. It is also suggested that these long, whip-like tails could have been used in intraspecific combat.

Apatosaurus scale drawing.
Scale drawing of Apatosaurus (A. ajax). Note the long, whip-like tail. New research suggests that these long tails could not be used to create a “crack” as they broke the sound barrier. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Supersonic Sauropod Tails

A sauropod clade, the Flagellicaudata are characterised by their extremely long tails. This clade includes the Diplodocidae family and the closely related Dicraeosauridae. Although complete fossil sauropod tails are extremely rare, palaeontologists have a good idea of the anatomy of a typical diplodocid tail. It consisted of approximately eighty caudal vertebrae, that gradually decrease in size and morphological complexity towards the tail tip. There are approximately ten larger posterior vertebrae, followed by forty or so intermediate bones with finally around thirty progressively smaller rod-like caudal vertebrae.

Earlier studies had suggested that the tail could be whipped, and the tip would travel so fast (in excess of 500 metres per second), this action would break the sound barrier and produce a loud sound. This speedy tail would cause a significant injury should it come into contact with another dinosaur.

However, this new study used three-dimensional models and computer analysis to assess the stress on the bones, ligaments and soft tissues. They concluded that the maximum tip velocity generated would be around thirty metres a second, nowhere near the 330 metres per second required to break the sound barrier.

Eofauna Diplodocus scale model
The Eofauna Diplodocus carnegii model measures around 60 cm in length and stands 11 cm tall. It is a 1/40th scale model. Most of the model’s length is made up of the long tail. Diplodocids are members of the Flagellicaudata clade.

The picture (above) shows the recently introduced Eofauna Scientific Research Diplodocus carnegii replica. When shown in lateral view, the extremely long tail can be seen.

To view the range of models and figures in the Eofauna series: Eofauna Scientific Research Models.

An Effective Weapon

Whilst the researchers conclude that the effect of friction on the musculature and aerodynamic drag would prevent the tail tip from reaching a speed capable of breaking the sound barrier, the pressure applied by the terminal section would not be enough to break bones or lacerate dinosaur skin, but it could still deliver a painful blow.

In summary, the scientists suggest that sauropod tail use remains speculative, these tails could have been used in intraspecific combat, or perhaps as a weapon against predators. Similarly, the use of the tail as a tactile element to retain herd cohesion is equally plausible.

The scientific paper: “Multibody analysis and soft tissue strength refute supersonic dinosaur tail” by Simone Conti, Emanuel Tschopp, Octávio Mateus, Andrea Zanoni, Pierangelo Masarati and Giuseppe Sala published in Scientific Reports.

2 01, 2023

The Evolution of the Backbone

By | January 2nd, 2023|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles|0 Comments

The evolutionary development of the vertebral column has been extensively researched. Numerous fossil specimens have been studied as scientists pursue a greater understanding of the evolution of the backbone. Recently, a new scientific paper has been published in “Scientific Reports” that outlines the evolutionary development of ossification patterns in four-legged vertebrates.

Research from the Museum für Naturkunde

The study was undertaken by scientists from the Museum für Naturkunde (Berlin, Germany). Antoine Verrière and his colleagues were able to reconstruct the patterns of how the bones in the vertebral column formed in the ancestor to all land vertebrates based on a large dataset compiled from studies of extant and extinct vertebrates. The dataset also included new information on the spine of Mesosaurus tenuidens, widely regarded as the first reptile to adapt to an aquatic existence, back in the Permian some 300 million years ago.

Evolution of the Backbone.
Understanding the evolution of ossification patterns in the backbones of four-legged vertebrates. Picture credit: Verrière and Fröbisch.

The Evolution of the Backbone

Lead author of the paper, Antoine Verrière explained that M. tenuidens had a long snout and a powerful tail that propelled it through the water. It inhabited an inland sea that once existed in the southern region of the supercontinent Pangaea.

The palaeontologist added:

“On some rare juvenile specimens, we observed that the neural arches, the spines sitting on top of the main part of a vertebra, were closing from head to tail as the animals grew, much like a zipper. We wanted to understand how this pattern would fit in the evolutionary history of land vertebrates, but quickly realised there was surprisingly little information available. So, we decided to investigate this ourselves!”

Four Major Developmental Patterns in Backbones of Amniotes

The research team looked at four of the major developmental patterns in the backbones of amniotes (mammals, reptiles and birds):

  • The ossification of the centrum (the main body of a vertebra).
  • The ossification of paired neural arches.
  • The fusion of the initially forming paired neural arch elements into one spine.
  • The fusion of neural arches with the centrum, also called neurocentral fusion.

Statistical analysis was used to model how these different patterns changed from the Permian through to today, their work roughly covering the evolutionary history of land-living vertebrates excluding amphibians. With this research the team could reconstruct the patterns in the common ancestor to all land vertebrates.

Co-author of the study, Professor Jörg Fröbisch (Museum für Naturkunde) commented:

“What surprised us the most was that these patterns appear to have been relatively stable for the last 300 million years. Modern and extinct vertebrates are enormously diverse in terms of their body shapes and lifestyles and the elements of their vertebral columns are organised in complex units that differ greatly between species. Nevertheless, the ossification patterns were much more conservative than was expected from the great morphological diversity.”

Edmontosaurus skeleton.
Duck-billed dinosaur on display showing the vertebral column. Despite vertebrates having extremely diverse body shapes and complex spines the observed ossification patterns were much more conservative than expected. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Some Deviations Identified

Although the patterns studied show relative stability through deep geological time, some deviations were identified. Notably, birds, mammals, and members of the Squamata Order (snakes and lizards) each evolved their own specific modes of vertebral ossification, which differ from the ancestral condition in amniotes. Yet again, within these groups, the patterns were also surprisingly stable.

Fellow co-author Professor Nadia Fröbisch (Museum für Naturkunde) explained:

“Ostriches and seagulls, for instance, have very different anatomies and lifestyles, but their vertebral columns ossify in similar ways. This shows that some changes can be observed between the major lineages of land vertebrates, but within each of the main lineages, spine development remained rather stable again.”

This study demonstrates how studying modern animals alongside their ancient ancestors can provide a much deeper understanding of the evolutionary development of key anatomical structures.

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

The scientific paper: “Regionalization, constraints, and the ancestral ossification patterns in the vertebral column of amniotes” by Antoine Verrière, Nadia B. Fröbisch and Jörg Fröbisch published in Scientific Reports.

29 12, 2022

Dwarf Nodosaurid Patagopelta

By | December 29th, 2022|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

In today’s blog post we look at the dwarf nodosaurid Patagopelta (P. cristata), which was formally named and described earlier this month.

A new, very small, armoured dinosaur has been named and described from fossils found in Argentina. The dinosaur which measured around 2 to 2.3 metres in length (based on the dimensions of the femur), suggests that some members of the Nodosauridae in Gondwana became smaller in the Late Cretaceous, perhaps as armoured dinosaurs in South America were under evolutionary pressure from other ornithischians and titanosaurs.

Dwarf nodosaurid Patagopelta
A life reconstruction of the newly described, dwarf nodosaurid from Argentina (Patagopelta cristata). Picture credit: Gabriel Diaz Yantén.

Dwarf Nodosaurid Patagopelta

Fragmentary remains of Late Cretaceous armoured dinosaurs are known from Chile and Argentina, but little work had been undertaken to assess these specimens and to review their phylogeny and taxonomic relationship with other members of the Ankylosauria clade from North America and elsewhere in the world.

Writing in the ” Journal of Systematic Palaeontology”, the researchers led by Facundo Riguetti, a CONICET doctoral fellow, reassessed the known ankylosaur material in conjunction with some other recently found fossils and, as a result, they were able to establish a new nodosaurid species from bones and a single tooth found in sediments of the Allen Formation (Campanian–Maastrichtian) in Salitral Moreno, Río Negro Province (northern Patagonia).

Patagopelta cristata

The dinosaur’s genus name translates as “Patagonian shield” whilst the trivial name derives from the Latin for crest – a reference to the diagnostic crests on both the anterior surface of the femur and the lateral osteoderms of the cervical rings.

Dr Riguetti commented:

“The importance of the study lies in the fact that Patagopelta is the first species of Ankylosauria described for the continental territory of Argentina, which fills the existing gap for this group and adds a new thyreophoran to the very few incomplete and indeterminate remains known for our country from this type of ornithischian dinosaur.”

Dwarf nodosaurid Patagopelta (views of the femur).
The right femur of Patagopelta (specimen number MPCA-SM-1), in A, anterior, B, posterior, C, lateral, D, medial, E, proximal and F, distal views. As the fragmentary left femur would have been the same size it is thought the femora came from a single animal. Other fossil remains represent several individuals. Abbreviations: fh, femoral head; fn, fibular notch; ft, fourth trochanter; gtr, greater trochanter; it, interwoven texture; lc, lateral condyle; le, lateral epicondyle; li (atr), linea intermuscular (associated to the anterior trochanter); lmca, linea muscularis caudalis; lmcr, linea muscularis cranialis; mc, medial condyle. Scale bar = 10 cm. Picture credit: Riguetti et al.

The Right Femur

The best-preserved fossil element is the right femur, which is complete and shows typical anatomical characteristics associated with the Nodosauridae. This bone along with the distinctive cervical osteoderms led to the erection of this new species. As the femur is only 25 cm in length and bone histology suggests an adult animal, the researchers conclude that Patagopelta was a dwarf form of armoured dinosaur.

Co-author Sebastián Apesteguía, a CONICET researcher, explained:

“For an armoured dinosaur, Patagopelta is extremely small. Due to the size of the femur, only 25 centimetres in length, we estimate that the animal must have been between two and three meters long, while, in general, ankylosaurs are medium-sized or large animals, with an average length of between four and five metres.”

A Faunal Exchange Across the Americas

Although it is thought that the Nodosauridae evolved in the Northern Hemisphere, towards the end of the Cretaceous (Campanian – Maastrichtian), a land bridge existed between North America and South America that permitted a faunal exchange. Titanosaurs migrated north, which explains why fossils of titanosaurs such as Alamosaurus occur in the USA. Ornithischian dinosaurs such as hadrosaurs and nodosaurids moved south.

Alamosaurus scale drawing.
Scale drawing of Alamosaurus. A giant titanosaur known from North America that is probably descended from titanosaurs that roamed South America. Picture credit: Everything Dinosaur.

The image above shows a typical Late Cretaceous titanosaur, for models of Late Cretaceous dinosaurs including titanosaurs and armoured dinosaurs: CollectA Prehistoric Life Models.

Sebastián Apesteguía added:

“That is why in South America we only expect to find animals like Patagopelta in rocks from the Late Cretaceous, just before the global extinction of the dinosaurs took place.”

Dwarfism in Late Cretaceous South American Thyreophora

The size of Patagopelta along with the recently described Stegouros (Soto-Acuña et al, 2021)*, from southernmost Chile, suggests that armoured dinosaurs in South America may have gradually become smaller. This trait is not known in members of the Thyreophora described from other parts of the world. Palaeontologists have speculated that perhaps competition from titanosaurs and the migration of hadrosaurs into South America might have led to armoured dinosaurs adapting to different ecological niches to avoid competition. By being smaller these animals needed fewer resources than larger, contemporaneous herbivorous dinosaurs.

It has also been suggested that the geology of Patagonia where the fossils of Patagopelta were found might provide a clue to the dwarfism. Geologists are aware of several Late Cretaceous marine transgressions in the region. This might have led to the establishment of an island archipelago with dinosaurs living on these small islands gradually become smaller due to a scarcity of resources (the “island rule”).

Tracks of Dwarf Ankylosaurs

Members of the Patagopelta research team had previously described tracks of dwarf ankylosaurs, possibly affected by similar circumstances, preserved in Upper Cretaceous deposits in Bolivia.

*To read Everything Dinosaur’s 2021 article about the discovery of Stegouros: New Armoured Dinosaur from Chile.

Everything Dinosaur acknowledges the assistance of a media release from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) in the compilation of this article.

The scientific paper: “A new small-bodied ankylosaurian dinosaur from the Upper Cretaceous of North Patagonia (Río Negro Province, Argentina)” by Facundo Riguetti, Xabier Pereda-Suberbiola, Denis Ponce, Leonardo Salgado, Sebastián Apesteguía, Sebastián Rozadilla and Victoria Arbour published in the Journal of Systematic Palaeontology.

23 12, 2022

Tooth Shape Helps Shape Dinosaur Diet

By | December 23rd, 2022|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

Recently published research examining tooth shape in early members of the Dinosauria has provided new information on dinosaur diet. The very earliest known dinosaurs included carnivores, herbivores as well as omnivores. Early dinosaurs were already developing adaptations to exploit a wide variety of feeding strategies.

Early dinosaur diet investigated.
Buriolestes (top left), a member of the Sauropodomorpha is a carnivore whilst the geologically younger sauropodomorph Thecodontosaurus is thought to have been herbivorous (top right). Lesothosaurus (bottom), an early member of the Ornithischia, is thought to be an omnivore. Picture credit: Gabriel Ugueto.

Picture credit: Gabriel Ugueto

Dinosaur Diet

Writing in the academic journal “Science Advances”, the scientists from the University of Bristol developed computer models to test the function and bite force of the teeth of a variety of early dinosaurs. These results were then compared with the data from extant lizards so that the diet could be inferred. The study shows that many groups of plant-eating ornithischian dinosaurs were ancestrally omnivorous and the ancestors of the huge sauropods, dinosaurs such as Apatosaurus, Diplodocus, Dreadnoughtus and Argentinosaurus were carnivores.

The scientists conclude that the ability of the Dinosauria to diversify their diets early in their evolution probably explains their evolutionary and ecological success.

Studying the Earliest Dinosaurs

The Dinosauria dominated terrestrial ecosystems for much of the Mesozoic. However, their origins and how they came to out compete other tetrapods during the Middle to Late Triassic remains the subject of intense debate. Over a few million years, the dinosaurs seem to have rapidly diversified and moved from being essential “bit-part” players in terrestrial ecosystems dominated by other types of archosaur and synapsid to becoming the dominant group.

Analysis of trackways discovered in the Southern Alps suggests a link between extensive faunal turnover leading to the dominance of the Dinosauria and the Carnian Pluvial Episode (CPE), a period of major climate change and a shift in the types of flora.

The diversification of the dinosaurs.
The diversification of the dinosaurs coincides with the Carnian Pluvial Episode (CPE). Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

To read more about this research into the impact of the Carnian Pluvial Episode on terrestrial ecosystems: Dinosaurs – In with a Bang and Out with a Bang.

A Wide Diversity of Different Skull and Tooth Shapes

Commenting on the implications of this study, lead author Dr Antonio Ballell stated:

“Soon after their origin, dinosaurs start to show an interesting diversity of skull and tooth shapes. For decades, this has made palaeontologists suspect that different species were already experimenting with different kinds of diets. They have compared them to modern lizard species and tried to infer what they ate based on the similarities in their teeth.”

Tooth morphology yields data on dinosaur diet.
Dinosaur skull shape and tooth morphology mapped over time. The three main dinosaur lineages, Sauropodomorpha, Ornithischia and Saurischia are represented from the Late Triassic to the Early Jurassic. Sauropodomorphs that were ancestral to the giant plant-eaters such as Apatosaurus and Dreadnoughtus were originally carnivorous, whilst ornithischian dinosaurs regarded as predominately herbivorous, started off as omnivores. Picture credit: Ballell, Benton and Rayfield.

Dr Ballell, based at the University’s School of Earth Sciences added:

“We investigated this by applying a set of computational methods to quantify the shape and function of the teeth of early dinosaurs and compare them to living reptiles that have different diets. This included mathematically modelling their tooth shapes and simulating their mechanical responses to biting forces with engineering software.”

A Plateosaurus dinosaur model.
A rearing Plateosaurus. The study confirmed that the large, Late Triassic Plateosaurus was in all probability a herbivore.

The Plateosaurus replica (above), is part of the CollectA not-to-scale range of prehistoric animal models.

To view this range: CollectA Prehistoric Life Models and Figures.

Predicting Dinosaur Diet

Co-author of the paper, Professor Mike Benton explained:

“With this battery of methods, we were able to numerically quantify how similar early dinosaurs were to modern animals, providing solid evidence for our inferences of diets. Theropod dinosaurs have pointy, curved and blade-like teeth with tiny serrations, which behaved like those of modern monitor lizards. In contrast, the denticulated teeth of ornithischians and sauropodomorphs are more similar to modern omnivores and herbivores, like iguanas.”

Innovative Machine Learning

This innovative research used machine learning models to group the earliest dinosaurs into different diet categories based on their jaw mechanics and tooth shape. For example, Thecodontosaurus, a dinosaur which roamed the Triassic archipelago where Bristol now stands, had teeth well adapted for feeding on plants.

Senior co-author, Bristol University’s Professor Emily Rayfield commented:

“Our analyses reveal that ornithischians, the group that includes many plant-eating species like the horned dinosaurs, the armoured ankylosaurs and the duck-billed dinosaurs started off as omnivores. Another interesting finding is that the earliest sauropodomorphs, ancestors of the veggie long-necked sauropods like Diplodocus, were carnivores. This shows that herbivory was not ancestral for any of these two lineages, countering traditional hypotheses, and that the diets of early dinosaurs were quite diverse.”

The Evolution of Different Diets

The researchers postulate that the ability for the Dinosauria to evolve different dietary habits may have played a key role in the ecological and evolutionary success.

Everything Dinosaur acknowledges the contribution of a media release from Bristol University in the compilation of this article.

The scientific paper: “Dental form and function in the early feeding diversification of dinosaurs” by Antonio Ballell, Michael J. Benton and Emily J. Rayfield published in Science Advances.

21 12, 2022

Dinosaur Eating a Mammal

By | December 21st, 2022|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

The first, definitive proof of a dinosaur eating a mammal has been found. A foot of a tiny, mouse-sized mammal has been discovered inside the body cavity of the feathered theropod Microraptor (M. zhaoianus). Previously, other Microraptor specimens from Lower Cretaceous rocks of northern China had revealed the fossilised remains of a fish, a primitive bird and a lizard associated with the body cavity. Palaeontologists now know that this crow-sized predator also ate mammals. This is the first record of a dinosaur consuming a mammal.

Dinosaur eating a mammal.
A life reconstruction showing the Microraptor with the mammal’s foot. Picture credit: Ralph Attanasia.

Mammal Foot Found Inside Ribcage

A new study led by Dr David Hone (Queen Mary University of London), published in the academic “Journal of Vertebrate Paleontology”, documents the first known incident of a dinosaur having eaten a mammal.

Microraptor is a genus of small, dromaeosaurid which lived in the forests of northern China around 120 million years ago (Early Cretaceous). The remarkable fossils found in Liaoning Province have enabled palaeontologists to build up a detailed picture of life in these ancient, dinosaur-dominated forests.

Researchers have also identified a wide variety of mammals and mammaliamorphs that co-existed with the dinosaurs and pterosaurs. Together these creatures make up a diverse ecosystem known as the Jehol biota

To read Everything Dinosaur’s blog post from 2021 describing the remarkable diversity of vertebrates associated with the Jehol biota: The Jehol Biota.

Microraptor had long feathers on its arms and legs and was, very probably arboreal, gliding from tree to tree, hunting out small animals to eat.

Mammal pes found in association with Microraptor fossil.
The mammal foot inside the Microraptor fossil. Picture credit: Alex Dececchi.

Spotting the Fossilised Foot

The Microraptor specimen was first described twenty-two years ago, but the preserved remains of the tiny foot had been overlooked. Professor Hans Larsson of McGill University in Montreal spotted what others had missed – the remains of another animal inside the Microraptor’s rib cage. In collaboration with Dr Hone, and colleagues from Canada, China and the USA, a paper describing this remarkable discovery has now been published.

Dinosaur eating a mammal.
A close-up view of the mammal’s foot inside the Microraptor skeleton. The foot bones have been outlined in red. Picture credit: Alex Dececchi with additional annotation by Everything Dinosaur.

Dinosaur Eating a Mammal

The mammal foot is almost complete and belonged to a very small animal, approximately the size of a modern house mouse. Examination of the bones suggest that it was one that predominantly lived on the ground and was not well adapted for climbing trees, making it an interesting prey choice for the mainly arboreal Microraptor.

Previous studies have revealed other Microraptor specimens containing the remains of a bird, a lizard and a fish. This specimen of the species Microraptor zhaoianus demonstrates that Microraptor also consumed small mammals. This little feathered dinosaur was a generalist, consuming a wide variety of prey.

It is not certain if the dromaeosaurids in question had directly preyed upon and eaten these animals or found them already dead and had scavenged them (or a mixture of both) but the mammal at least falls into the range of typical prey size predicated for a predator the size of Microraptor.

Dinosaur eating a mammal.
An extreme close-up view of the mammal pes (foot) inside the fossil of Microraptor. Picture credit: Alex Dececchi.

Dr Hone’s co-authors on the paper include Dr Alex Dececchi, Mount Marty College (USA), Dr Corwin Sullivan at the Department of Biological Sciences, University of Alberta, and Professor Xu Xing at the Institute of Vertebrate Palaeontology and Palaeoanthropology, Beijing.

A Significant Fossil Discovery

Commenting on the significance of this fossil discovery, Dr David Hone stated:

“It’s so rare to find examples of food inside dinosaurs so every example is really important as it gives direct evidence of what they were eating.

Dr Hone from the University’s School of Biological and Behavioural Sciences added:

“While this mammal would absolutely not have been a human ancestor, we can look back at some of our ancient relatives being a meal for hungry dinosaurs. This study paints a picture of a fascinating moment in time – the first record of a dinosaur eating a mammal – even if it isn’t quite as frightening as anything in Jurassic Park.”

Co-author of the study, Dr Alex Dececchi, from Mount Marty College, commented:

“The great thing is that, like your housecat which was about the same size, Microraptor would have been an easy animal to live with but a terror if it got out as it would hunt everything from the birds at your feeder to the mice in your hedge or the fish in your pond.”

Everything Dinosaur acknowledges the assistance of a media release supplied by Dr David Hone in the compilation of this article.

The scientific paper: “Generalist diet of Microraptor zhaoianus included mammals” by Hone, D.W.E., Dececchi, T.A., Sullivan, C., Xu, X. and Larsson, H.C.E. published in the Journal of Vertebrate Paleontology.

Correction

This is not the first recorded incidence of a dinosaur consuming a mammal. The press release, although provided by the appropriate authorities, had failed to recognise evidence cited in an earlier scientific paper.

14 12, 2022

Tail Clubs for Social Dominance

By | December 14th, 2022|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Ankylosaurs battled each other using their tail clubs for social dominance in intraspecific combat. A recently published scientific paper on the ankylosaur Zuul crurivastator suggests that these armoured dinosaurs used their tail clubs to bash each other as well as to fend off tyrannosaurs.

In the study, published in “Biology Letters” the research team, examined the osteoderms of the remarkably well preserved Zuul crurivastator, an armoured dinosaur described from fossils found in the Coal Ridge Member of the Judith River Formation (Montana). Several of osteoderms along the flanks show signs of damage and healing which led the scientists to postulate that these dinosaurs battled each other with their tail clubs. These fights would have been for social or territorial dominance, perhaps even a result of a “rutting” season fighting for mates – behaviour associated with many mammals today.

Tail clubs for social dominance.
A pair of ankylosaurs (Zuul crurivastator) indulge in some intraspecific combat. Picture credit: Henry Sharpe

Zuul crurivastator

Named and formally described in 2017, Zuul crurivastator (pronounced Zoo-ul cruh-uh-vass-tate-or) roamed the northern part of Laramidia approximately 76 million years ago (Campanian faunal stage of the Late Cretaceous).

To read Everything Dinosaur’s 2017 blog post about the fossil discovery: Zuul – The Destroyer of Shins.

Zuul’s body was covered in bony plates (osteoderms) of different shapes and sizes and the ones along its flanks were particularly large and spiky. Interestingly, the scientists which included lead author and renowned ankylosaur expert Dr Victoria Arbour (Royal British Columbia Museum, Canada), noted that dermal armour near the hips on both sides of the body showed damage that had subsequently healed. This localised, bilaterally symmetrical pathology is speculated to have been caused by ritualised combat rather than wounds inflicted by an attacking theropod dinosaur.

Damaged osteoderms on the Zuul Holotype
Identifying damaged osteoderms in the holotype of Zuul crurivastator. A composite photograph of the skull, first cervical half ring, body block and tail block (top). Fossil material is brown and surrounding rock matrix is grey. Interpretive illustration showing non-pathological osteoderms in white and pathological osteoderms in red (bottom). Picture credit: Arbour, Zanno and Evans.

An Exciting Piece of the Ankylosaur Puzzle

Dr Arbour commented:

“I’ve been interested in how ankylosaurs used their tail clubs for years and this is a really exciting new
piece of the puzzle. We know that ankylosaurs could use their tail clubs to deliver very strong blows to an opponent, but most people thought they were using their tail clubs to fight predators. Instead, ankylosaurs like Zuul may have been fighting each other.”

The genus name honours a fictional monster from the 1984 film “Ghostbusters”, whilst the trivial part of the binomial name translates as “the destroyer of shins”, a nod to the idea that tail clubs were used as defensive weapons to deter attacks from predatory theropod dinosaurs. The substantial club on the end of the three-metre-long tail being used to bash into the lower legs of tyrannosaurs. This new research does not refute the idea that these tail clubs had a role in defence, but based on the pathology seen in the Zuul holotype (specimen number ROM 75860) the scientists propose that sexual selection and intraspecific combat drove their evolution. Many mammals today such as deer, antelope, cattle and sheep have horns and antlers that have evolved for use in battles between members of the same species.

Damaged osteoderms in an ankylosaur.
Details of pathological and non-pathological osteoderm morphology in ROM 75860 (Zuul crurivastator). B2R and E3R are non-pathological flank osteoderms. F3R and D3R are pathological flank osteoderms missing the tips of the apex, and the keratinous sheath has not grown over the tip. D3L is a pathological flank osteoderm missing a large portion of the apex, and the keratinous sheath has overgrown the damaged region. C3L and E3L are pathological flank osteoderms with highly modified morphologies, missing large portions of the trailing posterior edge and with the keratinous sheath covering the damaged region. Picture credit: Arbour, Zanno and Evans.

It had been suggested previously that ankylosaurs may have clubbed each other, and that broken and healed ribs could provide evidence to support this idea. Unfortunately, ankylosaurid skeletons are extremely rare in the fossil record, these animals were not common, even in the Late Cretaceous of North America, where the ecosystem was dominated by other ornithischian dinosaurs such as duck-billed dinosaurs and ceratopsians.

Implications for Ankylosaur Behaviour

The remarkable Zuul fossil skeleton provides palaeontologists with an opportunity to study pathology recorded on the bones and dermal armour.

Co-author Dr David Evans (Curator of Vertebrate Palaeontology at the Royal Ontario Museum) explained:

“The fact that the skin and armour are preserved in place is like a snapshot of how Zuul looked when it
was alive. And the injuries Zuul sustained during its lifetime tell us about how it may have behaved and
interacted with other animals in its ancient environment.”

Tail Clubs for Social Dominance

The researchers conclude that the imposing tail club of Zuul could have been used in defence when needed, but the analysis suggest that sexual selection drove the evolution of this weapon. This finding has consequences for how palaeontologists perceive ankylosaurs. It suggests that these dinosaurs were capable of complex behaviours and that they likely engaged in ritualised combat over mates or for social dominance as inferred in other types of dinosaurs and observed in living mammals and birds.

Everything Dinosaur acknowledges the assistance of a media release from the Royal Ontario Museum in the compilation of this article.

The scientific paper: “Palaeopathological evidence for intraspecific combat in ankylosaurid dinosaurs” by Victoria M. Arbour, Lindsay E. Zanno and David C. Evans published in Biology Letters.

13 12, 2022

Spinosaurus Not an Aquatic Dinosaur

By | December 13th, 2022|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|1 Comment

A recently published scientific paper has refuted the idea that Spinosaurus (S. aegyptiacus) was an aquatic dinosaur. Writing in the academic journal eLife, the researchers which included Paul Sereno (University of Chicago), conclude that Spinosaurus was not aquatic. Instead, they revert to the earlier hypothesis that this super-sized carnivore was a semi-aquatic, bipedal predator that did feed on fish but ranged far inland.

Over a decade ago, Everything Dinosaur team members were contacted by members of the CGI team working on the Spinosaurus segment of the soon to be launched television series entitled “Planet Dinosaur”. At the time, (2010), S. aegyptiacus was thought to be a semi-aquatic, bipedal predator that specialised in hunting fish, but was not thought to be an almost entirely aquatic dinosaur.

The front cover of the book "Planet Dinosaur"
From paddler to swimming and back to paddler again – the “evolving” image of Spinosaurus. A recently published paper refutes the hypothesis that Spinosaurus aegyptiacus was an aquatic animal. Researchers postulate that it was semi-aquatic, a biped feeding on fish but not a dinosaur that could dive and swim very efficiently. Picture credit: BBC Worldwide.

Picture credit: BBC Worldwide

The 2014 Scientific Paper

In 2014, Paul Sereno (the lead author of the latest paper), was one of the authors of a study into Spinosaurus material found in Morocco. In the paper, the researchers proposed that this huge theropod possessed adaptations that indicated a semi-aquatic lifestyle. The skull had small nostrils located further up the snout to allow this dinosaur to breathe whilst its jaws were partially submerged and neurovascular openings along the jaws were interpreted to be sense organs that permitted Spinosaurus to sense the movements of fish through the water. Analysis of the centre of gravity indicated that Spinosaurus was a quadruped.

To read Everything Dinosaur’s blog post about the 2014 study: Spinosaurus – Four Legs are Better than Two!

However, commenting on the 2014 paper, Professor Sereno admits that there was a mistake made when examining the centre of gravity of Spinosaurus. When the centre of gravity was calculated leading to the conclusion that this huge theropod walked on all fours, the volume of the lungs were not properly accounted for. When a new assessment of the centre of gravity is made, using a more accurate lung volume assessment, the results are radically different. The data suggests that Spinosaurus was a biped, with a typical posture associated with other large-bodied carnivorous dinosaurs.

Spinosaurus model.
The new research which included a more accurate assessment of lung volume, indicates that Spinosaurus was bipedal, perhaps the Jurassic Park III Spinosaurus was not that inaccurate after all?

The image (above) depicts Spinosaurus with the typical bipedal posture of a large-bodied theropod dinosaur. The model is a Nanmu Studio Spinosaurus (version 2.0).

To view the range of Nanmu Studio models and figures available from Everything Dinosaur: Nanmu Studio Dinosaur and Prehistoric Animal Replicas.

The Fleshy Spinosaurus Tail

In 2020, another paper was published which examined the caudal vertebrae of Spinosaurus aegyptiacus, tail bones having not been part of previous studies. Writing in the journal “Nature” the researchers which included Nizar Ibrahim (University of Detroit Mercy, Detroit), along with colleagues from the University of Portsmouth, proposed that Spinosaurus had a broad, flexible, fin-like tail that could have propelled this dinosaur through the water. This seemed to be the decisive evidence, that Spinosaurus was indeed an aquatic hunter.

To read Everything Dinosaur’s blog post about the 2020 paper: Spinosaurus – The River Monster.

Spinosaurus was not Aquatic

In this newly published research, Sereno and his colleagues looked at the biomechanics of the fin-like tail and analysed its effectiveness as an organ of propulsion through water. When compared to alligators, the tail and hind feet of Spinosaurus were found to be very inefficient swimming organs. Spinosaurus was an unstable, slow-surface swimmer only capable of a swimming speed of less than one metre a second.

Spinosaurus tail bones compared to semi-aquatic and aquatic vertebrate caudal vertebrae.
Comparing the skeleton of S. aegyptiacus with a basilisk lizard and aquatic vertebrates. The tail of S. aegyptiacus (A) showing the overlap of neural spines (red) with more posterior caudal vertebrae. A CT scan showing the sail structure of a green basilisk lizard (B). Researchers propose that the tail of Spinosaurus was not adapted to propulsion in water but most probably a display structure. Skeletal illustrations of the caudal vertebrae of aquatic vertebrates (C) – crested newt, a mosasaur, crocodilian and a whale. A graph plotting the centrum proportions along the tail (D) comparing S. aegyptiacus with a crested newt (Triturus cristatus), semi-aquatic lizards (marine iguana Amblyrhynchus, common basilisk Basiliscus basiliscus, Australian water dragon Intellagama lesueurii and a sailfin lizard Hydrosaurus amboinensis), a mosasaur and an American alligator (Alligator mississippiensis). Picture credit: Sereno et al.

The team also calculated that Spinosaurus would have been too buoyant to submerge fully. It was not capable of diving and those robust, heavy hind limbs helped it to walk on land or wade, not acting as additional ballast to help this fifteen-metre-long giant remain underwater.

Sereno and his fellow authors suggest that living reptiles with similar tail bone morphology, such as the basilisk lizard, do not use their tails for propulsion, instead they have a display function.

Spinosaurus Ranged Far Inland

Fossils ascribed to Spinosaurus recovered from fluvial deposits in Niger suggest that this dinosaur ranged far inland. It is true that most Spinosaurus fossils come from sediments that represent extensive coastal deltas. However, these deposits include a large number of non-spinosaurid dinosaur remains, all of which may have been transported for some distance downstream. Spinosaurus fossil material may have also been transported, leading to the misconception that this was a dinosaur confined to the coast. Recently discovered fossils ascribed to Spinosaurus from two inland basins in Niger (Égaro North), indicate that Spinosaurus lived far from the shore. These fossils which include part of an upper jaw (maxilla) were found in fluvial deposits in association with rebbachisaurid and titanosaurian sauropods which are regarded as entirely terrestrial animals.

Spinosaurus was not aquatic
Spinosauridae fossil localities mapped (Early Cretaceous Albian faunal stage). The map (A) shows the fossil location for Baryonyx and Suchomimus (baryonychines) along with spinosaurs (Ichthyovenator, Vallibonavenatrix, Oxalaia, Irritator/Angaturama and Spinosaurus). Yellow asterisks indicate location of Spinosaurus fossils, these range from coastal sites (1 – Bahariya, Egypt and 2 – Zrigat, Morocco) to a site much further inland (3 – Égaro North, Niger). Spinosaurus sp. right maxilla (B), specimen number MNBH EGA1 from central Niger, in medial and ventral views. The inset image shows the fossil material superimposed on the snout of S. aegyptiacus. Abbreviations: am, articular rugosities for opposing maxilla; aofe, antorbital fenestra; Ba, Baryonyx walkeri; en, external naris; Ic, Ichthyovenator laosensis; Ir, Irritator challengeri/Angaturama limai; m3, 12, maxillary alveolus 3, 12; Ox, Oxalaia quilombensis; Su, Suchomimus tenerensis; t, tooth; Va, Vallibonavenatrix cani. Scale bar is 10 cm. Picture credit: Sereno et al.

Comfortable in Water but Not Truly at Home in an Aquatic Environment

Confirming that the researchers think Spinosaurus was a bipedal, semi-aquatic animal that specialised in hunting fish, Professor Sereno added:

“Do I think this animal would have waded into water on a regular basis? Absolutely, but I do not think it was a good swimmer or capable of full submergence behaviour.”

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

The scientific paper: “Spinosaurus is not an aquatic dinosaur” by Paul C Sereno, Nathan Myhrvold, Donald M Henderson, Frank E Fish, Daniel Vidal, Stephanie L Baumgart, Tyler M Keillor, Kiersten K Formoso and Lauren L Conroy published in eLife.

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