All about dinosaurs, fossils and prehistoric animals by Everything Dinosaur team members.
/Dinosaur and Prehistoric Animal News Stories

Fossil finds, new dinosaur discoveries, news and views from the world of palaeontology and other Earth sciences.

9 05, 2020

Reconstructing a Late Cretaceous Ecosystem

By | May 9th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

Reconstructing a Dinosaur Dominated Ecosystem

A team of international researchers including scientists from the Royal Ontario Museum (Toronto, Canada), have provided a new perspective on the palaeoenvironment of western North America during the Late Cretaceous.  An extensive study mapping stable isotopes identified in fossilised teeth has provided the research team with detailed information on how some dinosaurs co-existed in a floodplain environment on the landmass of Laramidia around 75 million years ago.

Many Different Types of Dinosaur are Associated with the Late Cretaceous of Laramidia

Dinosaur dominated ecosystem of Laramidia.

A large variety of different types of dinosaur co-existed on Laramidia.  Ornithischian dinosaurs such as ankylosaurs, ceratopsians, hadrosaurs as well as Saurischian dinosaurs such as dromaeosaurs, ornithomimids and tyrannosaurs.  They shared their tropical environment with turtles and numerous types of crocodilian.

Picture Credit: Danielle Dufault (Royal Ontario Museum)

Niche Partitioning in the Dinosauria

Palaeontologists had puzzled over how so many different types of large tetrapod could co-exist together and it had been thought that extensive niche partitioning between species must have been taking place.  Niche partitioning describes the natural selection process whereby different species reduce competition amongst themselves by becoming more specialised and adopting specific roles within an ecosystem.  They become adapted to a particular niche and by doing this competition between species is reduced.

Niche Partitioning Between Ceratopsids and Hadrosaurids

The fauna and flora of Alberta 75 million years ago

Alberta around 75 million years ago (Dinosaur Park Formation).  This part of the western North American landmass (Laramidia), was home to a large number of different types of dinosaur including a number of ceratopsians and duck-billed dinosaurs.  It had been suggested that niche partitioning permitted these mega-herbivores to co-exist with each type of plant-eating dinosaur specialising on feeding upon different types of vegetation.

Picture Credit: Julius Csotonyi

Stable Isotope Analysis

Researchers from the Royal Ontario Museum in collaboration with colleagues from the Field Museum in Chicago (USA), compared the compositions of stable isotopes identified in the fossilised teeth of different dinosaur taxa.  Stable isotopes are naturally occurring varieties of chemical elements such as oxygen and carbon that don’t alter and change into other elements over time. When water and food is consumed the stable isotopes of the elements that make up these resources (for example, nitrogen, carbon and oxygen), are passed on to the animal’s tissues including their teeth enamel.

Lead author of the research paper, published by the Geological Society of America, Dr Thomas Cullen (University of Toronto/Royal Ontario Museum), stated:

“Differences in the sources of water and types of food being consumed, as well as the physiology of the animal itself and the habitats they live in, will all result in small differences in the relative amounts of the stable isotopes of a given element, for example, carbon-13 versus carbon-12, present in their body tissues.  Measuring the ratios of the different isotopes of elements such as carbon or oxygen in tissues like tooth enamel gives us a unique window into the diet and habitat of an animal which has been extinct for millions of years.”

One of the Largest Studies of its Type Conducted

This research is one of the largest studies of its kind conducted on a dinosaur dominated ecosystem.  Over 350 isotopic measurements from 17 different taxa from fossils representing the Campanian fauna of Alberta.  Uniquely, this ancient data set was then compared and contrasted with measurements from 16 living species sampled from a modern coastal wetland in Louisiana, which closely resembles the climate conditions with northern Laramidia during the Late Cretaceous.

One of the co-authors of the study, Dr David Evans (Royal Ontario Museum), commented:

“Most of the time when these types of studies are done, the size of the dataset is much smaller and doesn’t take into consideration how dinosaur ecosystems compared to modern ones.  Louisiana was the perfect place to use as a comparison with the dinosaur communities we studied.  The environmental conditions were probably quite similar, and a number of the animals there probably had similar lifestyles to those found in dinosaur ecosystems.  That gives us a great deal of control when exploring our data.”

Typical Dinosaur Biota from the Campanian Faunal Stage of Northern Laramidia

Dinosaur Park Formation dinosaurs.

Typical dinosaur fauna of the Dinosaur Park Formation (Alberta, Canada).  A typical dinosaur dominated fauna associated with the study.

Picture Credit: Everything Dinosaur

Challenges Existing Theories

The team’s results challenge existing theories about niche partitioning and habitat exploitation.  For example, it had been suggested that the horned dinosaurs tended to congregate in coastal areas, whereas hadrosaurids preferred inland habitats.  The stable carbon and oxygen isotope ranges for these large herbivores were found to strongly overlap, providing direct evidence against different types of mega-herbivore segregating.

Large herbivores did not appear to be separating across different habitats.  The researchers conclude that these animals may have been doing something different to avoid interspecific competition.  Perhaps herds of horned dinosaurs moved around the region in a different pattern compared to the herds of duck-billed dinosaurs.  In this way, they may have avoided being in the same part of the habitat at the same time, or perhaps they were feeding on different parts of the same plants.  With the high levels of carbon dioxide in the atmosphere, the high average temperatures of 16-20 degrees Celsius and the extended daylength at certain times of the year due to the high latitude, competition for food might have been somewhat less intense than it is in modern ecosystems.

Extensive Vertebrate Fossil Deposits Have Helped to Inform Scientists About Ancient Ecosystems

Excavating an Edmontosaurus.

Extensive bonebeds and other fossil deposits have helped to inform scientists about the ancient ecosystem.

Picture Credit: Victoria Arbour

Results Helping to Understand the Implication of Global Warming

The isotope analysis enabled the scientists to accurately estimate the climate in this northern Laramidian palaeoenvironment.  By using an approach that combined average oxygen isotope compositions from the sampled species, new estimates of mean annual temperatures for the region could be made.  The team found that 75-million years ago, this area of southern Alberta to northern Montana had a mean annual temperature of about 16-20 °Celsius, a stark contrast to the current range of about 5-7 °Celsius that is experienced today.

Dr Cullen explained:

“Dinosaurs lived in a weird world: broad-leafed and flowering plants were much less common, it was warm enough in high latitudes to support crocodilians, CO2 in the atmosphere was higher than it is today, and there was little to no ice at the poles.  It’s not like anything we as humans have any direct experience with, but it may be the direction we are headed, so it’s critical that we understand how ecosystems and environments function under those sorts of conditions so we can better prepare ourselves for the future.”

The scientists conclude that that this approach is a simple and effective method that enables accurate palaeoenvironmental reconstruction.  These results indicate that dinosaur niche partitioning was much more complex than previously thought.  This study can provide a framework for future research on dinosaur-dominated Mesozoic floodplain communities.

The scientific paper: “Large-scale stable isotope characterization of a Late Cretaceous dinosaur-dominated ecosystem” by T.M. Cullen, F.J. Longstaffe, U.G. Wortmann, L. Huang, F. Fanti, M.B. Goodwin, M.J. Ryan and D.C. Evans published by the Geological Society of America.

6 05, 2020

“Raptors” Did Not Hunt in Packs

By | May 6th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

New Study Challenges Dromaeosaurids Hunting in Packs

The “Jurassic Park/Jurassic World” movie franchise certainly spawned new generations of dinosaur fans.  It could be argued that these extremely successful films, may have influenced the career choices of would-be scientists.  All very well and good, but one of the problems associated with the films and with the original book “Jurassic Park” written by Michael Crichton, concerns the “raptors”, those fast running, social pack hunters the size of Deinonychus but in this franchise referred to as Velociraptors.

Popular media has depicted these “raptors” as highly social, intelligent animals capable of working together to attack and bring down prey, but what scientific evidence is there to back-up the on-screen abilities of these dinosaurs?

Since it is very rare for the fossil record to preserve behaviour, scientists have had to employ some ingenious lines of research in order to gain an insight into the behaviour of dinosaurs.  For example, researchers from the University of Wisconsin, the University of Oklahoma and the Sam Noble Museum (Oklahoma), set about analysing differences in stable carbon isotopes within Deinonychus teeth.  Differences in the composition of these stable isotopes in teeth from young dinosaurs when compared to the isotopes found in the teeth of adults, would indicate a different diet.

If the adults had a different diet compared to the younger animals then this would contradict the idea of these dinosaurs being social and hunting in packs.

They conclude that Deinonychus probably did not hunt in a co-operative, co-ordinated manner.  These “raptors” were probably not complex, social hunters.

Actor Chris Pratt the “Alpha Male” with one of his “Pack” Members

A Velociraptor from the movie.

A stalwart of the “Jurassic Park” franchise – the “raptor” but what scientific evidence is there to suggest that these theropods were pack hunters?

Picture Credit: Universal Studios

Laying a Ghost – Highly Intelligent, Pack Hunting “Raptors”

The idea of pack hunting in dromaeosaurids pre-dates “Jurassic Park”, it was first proposed to explain the co-occurrence of Deinonychus (D. antirrhopus) and the iguanodontian Tenontosaurus (T. tilletti).  Around a fifth of all Tenontosaurus remains are found in association with D. antirrhopus.  It has been proposed that Deinonychus hunted the larger Tenontosaurus and as numerous fossil specimens of Deinonychus have been found with Tenontosaurus remains it was suggested that this was evidence of pack hunting behaviour amongst members of the Dromaeosauridae.

A Pack of “Raptors” (Deinonychus) Attack a Tenontosaurus

Deinonychus attacking Tenontosaurus.

A pack of Deinonychus attacking the herbivore Tenontosaurus.  Pack hunting behaviour inferred from fossil evidence.

Picture Credit: John Sibbick

The depiction of dromaeosaurs as pack hunters is problematic as sophisticated hunting strategies are rarely observed in living archosaurs such as crocodiles and birds.   Palaeontologists have considered that perhaps Deinonychus was more analogous to extant reptilian predators such as the Komodo dragon (V. komodoensis), where there seems to be no co-ordinated attack strategy, instead an attack by an individual may instigate mobbing behaviour which would bring down the prey.

Lead author of the study, published in Palaeogeography, Palaeoclimatology, Palaeoecology, Dr Joseph Frederickson (University of Wisconsin), explained:

“The evidence for this behaviour [pack hunting], however, is not altogether convincing.  Since we can’t watch these dinosaurs hunt in person, we must use indirect methods to determine their behaviour in life.  Though widely accepted, evidence for the pack-hunting dinosaur proposed by Yale University palaeontologist John Ostrom is relatively weak.  The problem with this idea is that living dinosaurs (birds) and their relatives (crocodilians) do not usually hunt in groups and rarely ever hunt prey larger than themselves.  Further, behaviour like pack hunting does not fossilise so we can’t directly test whether the animals actually worked together to hunt prey.”

Social Pack Hunters versus Mob Hunters

In order to test the likelihood of Deinonychus being a social pack hunter or whether these dinosaurs simply mobbed victims in an uncoordinated manner, the researchers looked at evidence for dietary changes preserved in the stable carbon isotopes found in fossilised Deinonychus teeth of various sizes.  The team analysed tooth carbonate from teeth less than 4.5 mm tall (crown height less than 4.5 mm) and compared the carbon isotopes found to those from much larger teeth (crown height greater than 9 mm).  The smallest teeth studied were the relatively most enriched with carbon-13 isotope, whilst the largest teeth used in the study had depleted levels.  These results suggest that juvenile Deinonychus consumed different prey than older members of this species.

Analysis of Stable Isotope Carbon-13 in the Teeth of Deinonychus Sheds Doubt on the Social Hunter Hypothesis

Isotope analysis of dinosaur teeth.

Deinonychus teeth – carbon-13 isotope analysis.  Tooth samples collected from the Lower Cretaceous Cloverly (Montana) and Antlers (Oklahoma) formations when analysed for carbon-13 levels suggest a dietary shift as Deinonychus matured.  This challenges the social, pack hunter hypothesis.

Picture Credit: Everything Dinosaur

Teeth from goniopholidid crocodilians as well as the teeth of Tenontosaurus tilletti were also tested.  The crocodilian results mirrored those found for Deinonychus.  If goniopholidid had the same behaviours of extant crocodilians then, just like their modern counterparts, these reptiles went through a distinct dietary transition as they grew.  If the teeth of Deinonychus show very similar results to the crocodilians, then, the implication is that just like crocodiles today, this “raptor” was probably not a complex social hunter it is unlikely that its hunting behaviour was comparable to the pack hunting behaviour of wolves or lions.

Still, the prospect of being mobbed by a gang of agile, three-metre-long, predatory dinosaurs remains unappealing.

A Model of a Deinonychus Dinosaur (D. antirrhopus)

The new for 2020 the Wild Safari Prehistoric World Deinonychus dinosaur model.

New for 2020 the Wild Safari Prehistoric World Deinonychus dinosaur model.  Evidence suggests that Deinonychus was not a social, sophisticated pack hunter.

Picture Credit: Everything Dinosaur

The scientific paper: “Ontogenetic dietary shifts in Deinonychus antirrhopus (Theropoda; Dromaeosauridae): Insights into the ecology and social behavior of raptorial dinosaurs through stable isotope analysis” by J.A. Frederickson, M. H. Engel, R.L. Cifelli published in Palaeogeography, Palaeoclimatology, Palaeoecology.

4 05, 2020

Stellasaurus – “Star Lizard”

By | May 4th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Stellasaurus ancellae – Missing Link from the Two Medicine Formation of Montana

A new species of horned dinosaur has been described based on fossil material from the famous Two Medicine Formation of north-western Montana.  The new species named Stellasaurus ancellae is a possible missing link in the evolutionary transition of Centrosaurinae dinosaurs from Styracosaurus to one of the last of the horned dinosaurs known to science – Pachyrhinosaurus.  Stellasaurus means “star lizard”, reflecting the ornate star-shaped head crest and in honour of British rock/pop star David Bowie, famous for his flamboyant appearance and his hit single “Starman” which was released on April 28th 1972, almost 48 years to the day that the Stellasaurus scientific paper was published in Royal Society Open Science.

United by a Flamboyant Appearance David Jones AKA David Bowie and “Star Lizard” AKA Stellasaurus

Two flamboyant characters David Bowie and Stellasaurus.

David Bowie (left) and Stellasaurus ancellae (right).

Picture Credit: Getty Images and Andrey Atuchin

Stellasaurus ancellae

Just like the career of David Bowie, Stellasaurus has had to wait a while before becoming famous.  The fossil material now assigned to Stellasaurus was discovered in 1986, near the town of Cut Bank in Montana, close to the USA/Canadian border.  The discovery was made by Carrie Ancell.  It remained catalogued but not studied in the Museum of the Rockies (Montana), vertebrate fossil collection.  The contribution of Carrie Ancell, now a senior preparator at the Museum of the Rockies, has been recognised as the species name honours her.  Carrie Ancell has played a significant role in developing our understanding of northern Laramidian centrosaurines.  She discovered and prepared MOR 492, the holotype specimen of Stellasaurus ancellae, as well as the holotype of Achelousaurus horneri, and co-discovered the holotype of Einiosaurus procurvicornis.

Views of the Holotype Fossil Material of Stellasaurus ancellae

Holotype fossil material for Stellasaurus ancellae

Left lateral parietal bar of Stellasaurus ancellae holotype MOR 492 in dorsal and ventral views.   The line drawing has been reproduced from a PLOS One article (Evans and Ryan).  Note scale bar on left equals 10 cm.

Picture Credit: Wilson et al/Royal Society Open Science

Reviewing the Centrosaurinae Fossil Material from the Two Medicine Formation

A review of cranial material, specifically the ornamentation associated with the neck frill (parietal processes), previously assigned to the centrosaurine Rubeosaurus ovatus resulted in the identification of this new taxon.  However, this assessment could mark the demise of R. ovatus as the researchers, which include John Wilson of Montana State University, conclude that only what was the holotype fossil, a partial parietal specimen number USNM 11869, can be attributed Rubeosaurus.  This could spell the end for Rubeosaurus.  When USNM 11869 was first described it was assigned to a new species of Styracosaurus (S. ovatus).  Thus, this new paper proposes that the genus Rubeosaurus is now no longer valid and that Styracosaurus ovatus is the sister taxon to Styracosaurus albertensis and Stellasaurus marks a missing link in centrosaurine evolution between Styracosaurus and Einiosaurus procurvicornis.

A Stratigraphical and Temporal Assessment of Late Cretaceous Centrosaurines Based on Two Medicine Formation Fossil Material *

The centrosaurine lineage from Styracosaurus to Pachyrhinosaurus.

Stratigraphic and temporal relationship between Two Medicine Formation centrosaurine taxa. * Pachyrhinosaurus lakustai fossil material is not from the Two Medicine Formation but from the younger unit 4 sediments of the Wapiti Formation of Canada.

Picture Credit: Wilson et al/Royal Society Open Science

A Missing Link Amongst the Centrosaurinae

The researchers postulate that Stellasaurus represents a missing link in the centrosaurine family tree.  The fossils of Stellasaurus are believed to be around 75 million years old.  From a stratigraphical perspective, they are younger than Styracosaurus albertensis fossils, but older than fossils assigned to Einiosaurus.  That flamboyant head shield with its various lumps and bumps could reflect a transitional stage between the headshield morphology of Styracosaurus and that of Einiosaurus.  It is suggested that Stellasaurus was preceded by Styracosaurus and that Styracosaurus evolved into Stellasaurus.  In addition, Einiosaurus evolved from Stellasaurus.

A Transitional Process – One Horned Dinosaur Leading Directly to Another Species of Horned Dinosaur

Anagenesis amongst centrosaurines.

Anagenesis within centrosaurine dinosaurs.  Stellasaurus evolved from Styracosaurus and Einiosaurus evolved from Stellasaurus.

Picture Credit: Everything Dinosaur/Andrey Atuchin

Anagenesis in the Centrosaurinae

Commenting upon the importance of this new research, lead author John Wilson stated:

“The ornamental horns and spiky frills on the skulls of these animals are what changed the most through evolution.  The new species has skull ornamentation which is intermediate.  This gives us evidence these species are members of a single, evolving lineage – this type of evolution is called anagenesis.”

The Phylogeny of the Centrosaurinae from Statistical Analysis Undertaken by the Research Team

Phylogeny of the Centrosaurinae based on Bayesian analysis.

Phylogeny of the Centrosaurinae clade of the Ceratopsidae based on Bayesian statistical analysis mapped against a temporal range.  Styracosaurus ovatus (formerly Rubeosaurus ovatus), is placed as the sister taxon to Styracosaurus albertensis, whilst Stellasaurus is mapped between S. albertensis and Einiosaurus procurvicornis.

Picture Credit: Wilson et al/Royal Society Open Science

The scientific paper: “A new, transitional centrosaurine ceratopsid from the Upper Cretaceous Two Medicine Formation of Montana and the evolution of the ‘Styracosaurus-line’ dinosaurs” by John P. Wilson, Michael J. Ryan and David C. Evans published in Royal Society Open Science.

2 05, 2020

Spinosaurus – The River Monster

By | May 2nd, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Spinosaurus an Aquatic Dinosaur

A team of international researchers including scientists from Leicester University, the University of Portsmouth and the University of Detroit Mercy, have published a paper in the academic journal “Nature” that concludes that the giant theropod Spinosaurus was indeed an aquatic animal.  In the autumn of 2014, a paper was published in the journal “Science” entitled “Semiaquatic adaptations in a giant predatory dinosaur”.  Spinosaurus was depicted as an obligate quadruped very much at home in the water.  In this latest publication, three of the authors involved in the earlier study, Nizar Ibrahim of the University of Detroit Mercy, Cristiano Dal Sasso and Simone Maganuco from the Natural History Museum of Milan (Italy), have collaborated with numerous other researchers in the analysis of Spinosaurus aegyptiacus tail bones.

The tail of Spinosaurus was unlike any other known theropod.  The fossil tail bones, indicate that the tail was wide, flexible and fin-like.  It seems very well adapted to propelling this huge dinosaur through water.  The researchers conclude that this is unambiguous evidence for an aquatic propulsive structure in a member of the Dinosauria.  In other words, Spinosaurus was very much at home in the rivers, swamps and lakes of the Cretaceous of northern Africa.  Here is one dinosaur that took to the water.

A Life Reconstruction of Spinosaurus (S. aegyptiacus) 2020

Swimming Spinosaurus 2020

A pair of spinosaurids hunting the giant, prehistoric sawfish Onchopristis.

Picture Credit: Davide Bonadonna/National Geographic

The beautiful illustration (above), depicts Spinosaurus hunting the 8-metre-long sawfish (Onchopristis).  A partial fossil jaw found in 1975 (MSNM V4047), attributed to Spinosaurus had a vertebra thought to have come from an Onchopristis embedded within it.  Although, the vertebra is thought to have become lodged after the Spinosaurus died, it demonstrated that Spinosaurus and this giant prehistoric fish were contemporaneous.

Not All Dinosaurs were Entirely Terrestrial

Unlike a lot of Kem Kem fossil material from Morocco, the Spinosaurus specimen, which was discovered in 2015, with the tail section found in 2018, consists of numerous associated bones.  Most of the vertebrate fossils found within these deposits are isolated, but these caudal vertebrae with their tall neural spines and elongated chevrons, have permitted the researchers to reconstruct the tail and to test its swimming capabilities using robotic flapping apparatus that was built to model the tail’s morphology and motion.  The researchers conclude that the tail of Spinosaurus was long, strong, flexible and ideal for propelling this monster through water.  It is likely that these fossils will provide much more information on the enigmatic Spinosaurus, as the material represents the most complete theropod dinosaur found to date in northern Africa.

The Reconstructed Spinosaurus – Obligate Quadruped with a Typical Theropod Tail (circa 2014)

Life-size reconstruction and supplemental figure from the autumn 2014 scientific paper.

Picture Credit: Davide Bonadonna (top) Ibrahim et al (bottom)

A Reconstruction of Spinosaurus aegyptiacus 2020

Swimming Spinosaurus (2020)

View of the crocodile-like snout of Spinosaurus and the new interpretation of the tail.

Picture Credit: Davide Bonadonna/National Geographic

The Tale of a Tail

Note the differences in the shape of the tail between the 2014 reconstruction and the very much more fin-like 2020 reconstruction.  The tail of Spinosaurus aegyptiacus has been described as resembling that of a giant crested newt.

Co-author of the scientific paper, Dr David Unwin (University of Leicester), commented:

“The Spinosaurus’ fin-like tail is a game changing discovery for us that fundamentally alters our understanding of how this dinosaur lived and hunted – it was actually a ‘river-monster’.  As well as its tail, many other features of this dinosaur, such as the high position of the nostrils, heavy bones, short legs and paddle-like feet point to a life spent in the water rather than on land.   Not only did dinosaurs dominate the land and take to the air as birds, they even went back into the water and became the top predators there as well.”

Papo Limited Edition Spinosaurus Model (2019)

Historically, some types of dinosaurs were associated with aquatic environments, for example, Jurassic sauropods and duck-billed dinosaurs such as Corythosaurus and Lambeosaurus.  However, these ideas have now been abandoned by most scientists and the Dinosauria is regarded as almost entirely terrestrial.  Recent studies have suggested that the enigmatic spinosaurids, dinosaurs such as Oxalaia, Irritator, Siamosaurus and Ichthyovenator along with Suchomimus, Baryonyx et al, may have been semi-aquatic.  This newly published paper demonstrates that Spinosaurus aegyptiacus possessed a number of anatomical adaptations indicating an aquatic habit.  In 2019, Papo introduced a new, limited edition figure of Spinosaurus, depicting this animal as a semi-aquatic, obligate quadruped.

The Papo Limited Edition Spinosaurus Figure (2019)

Papo Limited Edition Spinosaurus Model.

The Papo Limited Edition Spinosaurus dinosaur model (2019).  This Papo replica depicted Spinosaurus with a fin-like tail, ironically, this shape of tail has now been proposed by vertebrate palaeontologists.

Picture Credit: Everything Dinosaur

A Close-up View of the Thick Tail Adapted for Swimming of the Papo Spinosaurus

Papo Limited Edition Spinosaurus tail.

The tail of the Papo Limited Edition Spinosaurus dinosaur model (2019).

Picture Credit: Everything Dinosaur

Implications for Other Members of the Spinosauridae

Spinosaurus aegyptiacus was one of the last of the spinosaurids.  The authors of the scientific paper postulate that other members of the Spinosauridae are thought to have had aquatic adaptations which suggests a substantial invasion of aquatic environments by this clade of theropods.

Our congratulations to the scientists for their research into this fascinating theropod, we look forward to further papers being published as the Spinosaurus material from the Moroccan site continues to be excavated.  Our congratulations to Papo, for producing a fantastic replica, that although might not depict the dinosaur as exactly as some palaeontologists might, but they do seem to have produced a tail that reflects the newly published scientific data.

Our review of the 2014 paper: Spinosaurus 2014 Scientific Paper Review.

To see the Papo range of prehistoric animal models including the limited edition Spinosaurus: Papo Dinosaurs and Prehistoric Animal Models.

The scientific paper: “Tail-propelled aquatic locomotion in a theropod dinosaur” by Nizar Ibrahim, Simone Maganuco, Cristiano Dal Sasso, Matteo Fabbri, Marco Auditore, Gabriele Bindellini, David M. Martill, Samir Zouhri, Diego A. Mattarelli, David M. Unwin, Jasmina Wiemann, Davide Bonadonna, Ayoub Amane, Juliana Jakubczak, Ulrich Joger, George V. Lauder and Stephanie E. Pierce published in the journal Nature.

1 05, 2020

The First Fossil Frog from Antarctica

By | May 1st, 2020|Animal News Stories, Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

The First Fossil Frog from Antarctica

A researcher from the Swedish Museum of Natural History in collaboration with colleagues from the University of Fribourg (Switzerland) and the Instituto Antártico Argentino based in Buenos Aires (Argentina), has published a scientific paper which provides details of the first fossil remains of a frog to have been found on the continent of Antarctica.

The fossils, consisting of a partial ilium and a bone from the skull which were found in Eocene-aged deposits on Seymour Island, resemble an extant lineage of frogs known as helmeted frogs (family Calyptocephalellidae). Until this discovery, no Cenozoic ectothermic continental tetrapods (amphibians and reptiles), had been documented from Antarctica.  The tiny frog fossils suggest that around 40 million years ago, climatic conditions at high latitudes in the southern hemisphere were still mild enough to support “cold-blooded” amphibians.

A Life Reconstruction of the Helmeted Frog Found on the Antarctic Peninsula (Seymour Island)

Fossil frog described from Antarctica.

Life reconstruction of the frog genus described from the Eocene of Antarctica.

Picture Credit: Pollyanna von Knorring / Swedish Museum of Natural History

Writing in the academic, on-line journal “Scientific Reports”, the researchers conclude that some Eocene freshwater habitats in Antarctica provided habitats that were favourable for cold-blooded (ectothermic) vertebrates such as frogs.  Antarctica was much milder than it is today, the warmest months of the year averaging around 13 degrees Celsius whilst temperatures in the winter would have dropped to below an average of 4 degrees Celsius.  Frogs were present in freshwater ecosystems at a time in the history of Antarctica where ice sheets had formed in upland areas towards the interior of the continent.

Views of the Fragmentary Ilium from Seymour Island

Frog ilium from the Antarctic.

Ilium (NRM-PZ B282) of Calyptocephalella sp. from Seymour Island, Antarctica.  Ilium in lateral (a), medial (b), ventral (c) and dorsal (d) views.  Scale bar equals 1 mm.

Picture Credit: Swedish Museum of Natural History

The fossil frog remains were collected during three joint Argentinian-Swedish expeditions to Seymour Island in the southern hemisphere summers 2011–13.  The bone fragments were concentrated from dry-sieved sediment samples. The closest living relatives of the Eocene specimen are limited to the Chilean Andes (Calyptocephalellidae).  With the discovery of the fossils on Seymour Island, the researchers conclude that these types of helmeted frog were much more widespread across what remained of Gondwana during the Eocene.

The material is housed in the palaeozoological collection of the Swedish Museum of Natural History, Stockholm.

The scientific paper: “First fossil frog from Antarctica: implications for Eocene high latitude climate conditions and Gondwanan cosmopolitanism of Australobatrachia” by Thomas Mörs, Marcelo Reguero and Davit Vasilyan published in Scientific Reports.

30 04, 2020

What Makes “Crazy Beast” So Crazy

By | April 30th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

The Very Strange Adalatherium hui

This week, has seen the publication in the journal “Nature” of a scientific paper describing a new species of bizarre mammal from the Late Cretaceous of Madagascar.  Named Adalatherium (A. hui), this cat-sized animal shared its island home with a variety of predators such as abelisaurid dinosaurs, crocodilians and snakes.  At an estimated three kilograms, Adalatherium was no giant, but the fossilised remains, which represent a near complete skeleton of an individual, indicate that this mammal was not yet fully mature when it died and as such, it is one of the largest members of the crown group of mammals described from Upper Cretaceous material.

A Life Reconstruction of Adalatherium (A. hui)

Adalatherium life reconstruction.

A life reconstruction of Adalatherium hui.

Picture Credit: Reuters

Madagascar became isolated from the rest of Gondwana around 88 million years ago.  Animals on the island were effectively marooned and many pursued a different evolutionary route compared to related forms on the rest of the super-continent.  Classified as a member of the Gondwanatheria, an extinct group of mammaliaforms confined to the southern hemisphere and up until now, only known from isolated teeth and fragmentary bones, the Adalatherium lineage developed an unusual and unique set of characteristics never seen before in a tetrapod.

“Crazy Beast”

The backbone has more vertebrae than any other Mesozoic mammal and one of its rear leg bones (tibia) was bowed.  How this animal moved around is a bit of a mystery, but the authors of the scientific paper suggest that this animal lived in burrows (fossorial).  The snout shows a mixture of primitive and very advanced anatomical traits.  Adalatherium had more foraminia, small holes in the nasal cavity that served as passageways for nerves and blood vessels, than any other mammal extinct or living today.  The snout was probably extremely sensitive and covered in whiskers, they may have helped it find its way about underground.  One foramen (hole for nerves or blood vessels), at the top of the snout has no know parallel with any other mammal.

These strange characteristics inspired the researchers to name this animal “crazy beast” from the local Malagasy and from the Greek.

The Preserved Skeleton of Adalatherium and Accompanying Line Drawing

Adalatherium fossil material and interpretative line drawing.

The articulated remains of Adalatherium hui and an accompanying line drawing.  Note scale bar in (a) equals 5 cm.

Picture Credit: Krause et al.

Corresponding author, Dr David Krause (Denver Museum of Nature and Science), commented:

“Knowing what we know about the skeletal anatomy of all living and extinct mammals, it is difficult to imagine that a mammal like Adalatherium hui could have evolved, it bends and even breaks a lot of rules.”

Dr Krause is no stranger to bizarre prehistoric animals from Madagascar.  In 2008, Everything Dinosaur wrote a blog post about the “frog from Hell”, a research team led by Dr Krause had discovered the fossilised remains of a giant frog that inhabited the Late Cretaceous of Madagascar.

To read more about this: Beelzebufo ampinga – a frog that could jump continents!

The scientific paper: “Skeleton of a Cretaceous mammal from Madagascar reflects long-term insularity” by David W. Krause, Simone Hoffmann, Yaoming Hu, John R. Wible, Guillermo W. Rougier, E. Christopher Kirk, Joseph R. Groenke, Raymond R. Rogers, James B. Rossie, Julia A. Schultz, Alistair R. Evans, Wighart von Koenigswald and Lydia J. Rahantarisoa published in the journal Nature.

29 04, 2020

Let’s Ear It for Thalattosuchians

By | April 29th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

Prehistoric Crocodiles and Whales  – Convergent Evolution

The evolution of the cetaceans from terrestrial ancestors to the fully adapted pelagic forms we see today has been well documented.  However, a group of archosaurs, specifically a clade of crocodyliformes – the thalattosuchians, underwent the transition from terrestrial animals to become fast swimming predators over a hundred million years earlier.  Two very different types of tetrapod became adapted to marine environments by developing flippers from limbs, streamlining their bodies and evolving tail flukes to aid propulsion in water.  New research from a team of scientists led by Julia Schwab of the University of Edinburgh, also reveals that part of the inner ear changed to and that both thalattosuchians and the later synapsids that became modern whales ended up with very similar inner ear anatomy – an example of convergent evolution.

Thalattosaurs Evolved into Fully Pelagic Marine Reptiles from Terrestrial Ancestors

Illustrating thalattosaurs.

Thalattosaurs illustrated.  The Thalattosuchia is a specious and both temporally and geographically widespread clade of marine crocodylomorphs that originated in the Early Jurassic.  This clade is regarded by most palaeontologists as comprising two families (Teleosauridae and Metriorhynchidae).  A new scientific paper suggests that these diapsids evolved an inner ear structure that was mimicked by later synapsids that evolved into modern whales and dolphins.

Picture Credit: David Peters

Computerised Tomography of Thalattosaur Skulls

Writing in the academic journal PNAS (Proceedings of the National Academy of Sciences of the United States of America), the researchers report on the use of CAT scans to examine the fossil skulls of a dozen different types of marine crocodile to examine the vestibular system of the inner ear.  This system consists of three looping semi-circular canals and helps with spatial awareness and balance.  As thalattosuchians evolved into fully marine forms, during a long semi-aquatic phase, the morphology of their ear canals changed.  The ear canals became smaller and fatter – a shape that made their sensory system less sensitive, an ear canal morphology shared with today’s extant cetaceans.

A Seven-metre-long Late Jurassic Marine Predator (Plesiosuchus manselii)

Marine crocodile (Plesiosuchus).

Plesiosuchus manselii illustrated.

Picture Credit: Fabio Manucci/University of Edinburgh

Adapting to a Marine Existence

The inner ear canal shape that is common to both thalattosaurs and cetaceans is an adaptation to a marine existence, whereby the buoyancy of the water supports the animal in what tends to be a more uniform medium such as the the Epipelagic and the Mesopelagic zones of the ocean.  This contrasts to the environment encountered by a terrestrial animal which has to cope with the full effect of gravity on its body and a more complex landscape.

The researchers conclude that the adaptations to the thalattosaurs sensory capabilities evolved in response to their marine existence, rather than driving them into it.

Commenting on the significance of this study, co-author Steve Brusatte (University of Edinburgh), stated:

“The ancient aquatic crocs developed unusual inner ears after modifying their skeletons to become better swimmers.  Whales also changed their ears in a similar way, but did it soon after entering the water.  It seems like the crocs and whales took similar, but different, evolutionary routes from land to water.”

The scientific paper: “Inner ear sensory system changes as extinct crocodylomorphs transitioned from land to water” by Julia A. Schwab, Mark T. Young, James M. Neenan, Stig A. Walsh, Lawrence M. Witmer, Yanina Herrera, Ronan Allain, Christopher A. Brochu, Jonah N. Choiniere, James M. Clark, Kathleen N. Dollman, Steve Etches, Guido Fritsch, Paul M. Gignac, Alexander Ruebenstahl, Sven Sachs, Alan H. Turner, Patrick Vignaud, Eric W. Wilberg, Xing Xu, Lindsay E. Zanno and Stephen L. Brusatte published in the Proceedings of the National Academy of Sciences of the United States of America.

27 04, 2020

Late Cretaceous Giant Shark from Spain

By | April 27th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Ptychodontid Sharks Grew Big and Lived for a Long Time

Scientists from the University of Vienna have been able to determine the approximate age and to estimate the rate of growth of an extinct species of shark that lived around 85 million years ago.  In addition, the researchers, writing in the open access on-line journal PLOS One, have estimated that this ammonite crunching fish could have been in excess of seven metres in length, but even though it was a giant, this shark was not yet fully mature and still had some growing to do.

Much of what we know about prehistoric sharks comes from studies of their fossilised teeth.  However, apart from providing indications on size, taxonomy and potential diet, these teeth do not provide a great deal of information about the life and the age of the individual.  In contrast, the calcified vertebrae of elasmobranchs (sharks, skates and rays), specifically the centra, yield important information about ecological and biological traits.  Two fossil shark vertebrae assigned to the genus Ptychodus found in northern Spain, have enabled researchers to gain valuable information on the life of a single individual animal that lived during the Late Cretaceous.

Site Photographs of the Shark Vertebrae

The shark vertebrae (articulated and disarticulated specimens).

Additional articulated (A, B) and disarticulated shark vertebrae (C,D) found in situ.  Scale bar (A) = 20 cm and scale bar = 3 cm in B, C and D).

Picture Credit:  K. Oppermann

A Shark from Northern Spain

The fossil material consists of a portion of the spine representing five articulated and several disarticulated vertebral centra from a single animal.  The fossils were found in Upper Cretaceous strata around six miles west of the town of Santander in northern Spain, from a limestone exposure close to the village of Soto de la Marina.  The extensive marine sediments document much of the Late Cretaceous – ranging from early Santonian through to Maastrichtian-aged deposits.  The shark fossils come a bedding plane representing the earliest Santonian (circa 85 million years ago).  Although no teeth were found in association with the fossil material, the scientists have referred this material to the Ptychodus genus.  A relatively common and widespread genus that specialised in eating hard-shelled animals such as shellfish and ammonites (duraphagous diet).

Calculating the Size of the Prehistoric Shark

Previous research had shown a link between the total length attained for several living shark species and the diameter of the vertebral centra.  The linear regression used to calculate potential length was applied to these fossils and the scientists concluded that the shark was between 4.3 to 7.07 metres in length.

Estimating the Size of the Ptychodus spp.

Scale drawing of Ptychodus specimen based on size estimates.

Estimated size of between 4.3 and 7.07 metres for the Ptychodus spp. from the Santonian of Spain.

Picture Credit: Patrick L. Jambura (University of Vienna)

Intriguingly, the centra of sharks also preserve evidence of growth rate, from which an age range can be deduced, just as the rings on a tree stump can provide an indication of the tree’s age.  An analysis of the centra from two fossils indicated that this shark was around thirty years old when it died, quite an age for a shark, although what age some sharks species alive today can live to remains unknown.  Based on this study, the researchers propose that ptychodontid sharks grew very slowly, matured very late, but also showed high longevity and had the potential to reach huge body sizes.

Calcification Pattern on the Centra Can Provide an Indication of Growth Rate and Age

Calculating the age of a prehistoric shark.

Close view and line drawing of the vertebral centra EMRG-Chond-SK-1a (A), whilst (B) shows a close view and accompanying line drawing of  EMRG-Chond-SK-1b, the second centra examined in this study.  Note scale = 1.5 cm.

Picture Credit: PLOS One (Jambura and Kriwet)

The scientific paper: “Articulated remains of the extinct shark Ptychodus (Elasmobranchii, Ptychodontidae) from the Upper Cretaceous of Spain provide insights into gigantism, growth rate and life history of ptychodontid sharks” by Patrick L. Jambura and Jürgen Kriwet published in PLOS One.

19 04, 2020

Wood You Believe It? Mahogany Dates Back to the Dinosaurs

By | April 19th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Canadian Fossil Proves Origins of Mahogany Earlier Than Previously Thought

A fossilised fruit found on a beach in Canada has been identified as having come from a member of the mahogany tree family (Meliaceae).  This suggests that this commercially important hardwood evolved in the Cretaceous.   The fossil is some 15-20 million years older than any other fossil found that has been ascribed to the Meliaceae.  This type of tree would have been familiar to the dinosaurs.  Indigenous to the tropics of the Americas, the discovery of this fossil which dates between 79-72 million years ago (Campanian stage of the Late Cretaceous), will support palaeoclimate studies of high latitudes and permit palaeobotanists to better understand how modern tropical, angiosperm dominated ecosystems developed.

The new species of Cretaceous-aged tree has been named Manchestercarpa vancouverensis.

Views of the Fossilised Mahogany Fruit (Manchestercarpa vancouverensis)

Fossil maghogany fruit - holotype material.

Fossil mahogany fruit (Manchestercarpa vancouverensis).  Holotype SH790 scale bars A-C equal 1 cm, scale bar in D equals 0.5 cm.

Picture Credit: Brian Atkinson (University of Kansas)

The picture (above), shows cross-sectional views of the fruit and seeds of the newly described species of Cretaceous mahogany (Manchestercarpa vancouverensis).   The thick-walled outer skin of the fruit (endocarp) is identified along with the middle portion, the flesh of the fruit (mesocarp).  Evidence of seeds inside the fruit has also been found.

Manchestercarpa vancouverensis

Today, mahogany is a commercially very important hardwood, valued for its strength and beauty.  It is used in cabinet making, furniture and for creating musical instruments.  In the days of sailing ships, mahogany was much prized as this tough wood did not splinter as much as European timber when struck by a cannonball.  The UK is the world’s second largest importer of mahogany, after the United States.  To a palaeobotanist, finding a fossil that is reminiscent of fruit associated with these trees, lets them know that tropical forests similar to the ones we know today were in existence at the time of the dinosaurs. Prior to this discovery, the oldest fossils attributed to the Meliaceae family date from the Palaeogene and Eocene such as those specimens found in the Green River Formation of Colorado.  However, the earliest previously recorded fossils associated with Melia are leaves and scientists have been reluctant to assign these fossils taxonomically.  The most diagnostic material are fossil fruits and these fossils have been found in several, geographically dispersed Eocene-aged deposits such as the London Clay and the Nanjemoy Formation of North America.  It seems that in the past, these types of trees and therefore tropical forests were much more widespread than they are today.

Author of the scientific paper, published in the American Journal of Botany, University of Kansas researcher Brian Atkinson stated:

“For understanding when many of the different branches of the tree of life evolved, we’re primarily dependent on the fossil record.  In this case, Meliaceae, the mahogany family, is an ecologically and economically important group of trees.  A lot of researchers have used this group as a study system to better understand the evolution of tropical rainforests.  This work is the first definitive evidence that the tropically important trees were around during the Cretaceous period, when we first start to see the modernisation of ecosystems and modern groups of plants.”

The rock containing the fossilised fruit was found on a beach at Shelter Point, Vancouver (British Columbia), by fossil collector Graham Beard, the director of the Qualicum Beach Museum of Natural History.  The matrix in which the fossil was found is associated with the Spray Formation (Campanian faunal stage).   The genus name honours palaeobotanist Steve Manchester (University of Florida Museum of Natural History).  The species name honours the location of the fossil find.

This paper clearly confirms a Cretaceous origin for Meliaceae and that important tropical families were present prior to the development of modern tropical ecosystems in the Cenozoic.

Graham Beard’s fossil hunting exploits have been featured in this blog before.  In 2011, Everything Dinosaur reported upon a paper that had been published naming a new species of Canadian pterosaur (Gwawinapterus beardi), that had been named in his honour.  A subsequent study published a year later, confirmed that the fossilised remains attributed to a late-surviving istiodactylid pterosaur actually represented the remains of a fish.  To the consternation of the academics associated with this study, it also turned out the Graham had been wrongly accredited with finding the fossil specimen.

To read more: Flying Reptile with “Piranha-like” Jaws the original article.

A second piece correcting the identity of the discoverer:  Mistake in Naming Pterosaur Fossil Discoverer.

The scientific paper: “Fossil evidence for a Cretaceous rise of the mahogany family” by Brian A. Atkinson published in the American Journal of Botany.

17 04, 2020

Why are Some Insects Iridescent?

By | April 17th, 2020|Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

Researchers Study Weevils from the Pleistocene

Scientists have been studying the preserved wing cases of ancient weevils to help them to better understand how the huge colour palette associated with insects evolved.  Writing in the academic, open-access journal “Biology Letters”, the researchers from University College Cork (Ireland), in collaboration with colleagues from Yale-NUS College in Singapore, subjected the preserved elytra of weevils found in Switzerland to powerful electron microscopy to analyse miniscule photonic nanostructures housed within the cuticular scales of the wing case.

The researchers conclude that the vibrant colours produced may have evolved as a form of crypsis (camouflage).

Pleistocene Weevil Scales Reveal Three-dimensional Photonic Nanostructures

Weevil scales from the Pleistocene reveal their secrets.

Pleistocene subfossil weevil scales from specimens L150D-L (a–d) and L150D-N (e–h) imaged using light microscopy (a, b, e, f) and SEM (c, d, g, h).  Light micrographs show the preservation of scales preserving bright blue, green and yellow hues, while electron micrographs reveal three-dimensional photonic nanostructures (b, d, f, h).  Regions bounded by white boxes in (a, c, e, g; a, e rotated 90° clockwise), respectively.

Picture Credit: McDonald et al published in Biology Letters

Three-dimensional Photonic Nanostructures Housed within Scales

With only the preserved elytra (wing cases), to study the researchers could not pin down the exact genus, but the vibrant greens, yellows and blues produced by the light reflecting structures (photonic nanostructures), identified in the cuticular scales are reminiscent of the living weevil genera Polydrusus or Phyllobius.  Although the optical properties of these miniscule structures are well understood, their evolutionary history remains somewhat opaque.  The specimens, believed to be around ten to sixteen thousand years old, were subjected to scanning electron microscopy and small-angle X-ray scattering techniques that revealed that the elytra possess a single-diamond photonic crystal nanostructure.  These “diamonds” are one of numerous types of crystal-like nanostructure found in nature that interacts with light to produce vivid colours, often with an iridescent, metallic hue.

A Life Reconstruction of One of the Pleistocene Weevils

Ancient weevil life reconstruction.

A life reconstruction based on the Swiss Pleistocene subfossil.

Picture Credit: James Mckay

Rarely Preserved in the Fossil Record

The preservation of three-dimensional nanostructures within the fossil record of the Insecta is extremely rare.  This study represents the second time such nanostructures have been found, the only other instance of such structures being recorded was discovered in another fossil weevil by two of the authors of this scientific paper Dr McNamara (University College Cork) and Assistant Professor Vinodkumar Saranathan (Yale-NUS College).  The team suggest that these hues evolved to allow the insects to blend into their background.  These substrate-matching green colours have been maintained over hundreds of thousands of generations suggesting that the same selective pressures for camouflage have been acting on these weevils over millennia.  This supports the idea that this type of colouration originally evolved to provide crypsis to prevent these small creatures being seen by potential predators.

The researchers suggest that the fossil record of insects, although sparse, could provide further evidence regarding the evolutionary history of colouration within the Insecta.

The scientific paper: “Brilliant angle-independent structural colours preserved in weevil scales from the Swiss Pleistocene” by Luke T. McDonald, Suresh Narayanan, Alec Sandy, Vinodkumar Saranathan and Maria E. McNamara published in Biology Letters.

Load More Posts