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

1 06, 2018

Pterosaur Models Go on Display

By | June 1st, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos|1 Comment

Pterosaurs at the Field Museum

Visitors to the famous Field Museum in Chicago (USA), might get into a bit of flap today, as they will be coming face-to-face with life-size replicas of flying reptiles.  The pterosaurs are part of a $16.5 million USD re-fit for the Museum.  They will be installed into the enormous Stanley Field Hall, sharing the space with a giant Titanosaur exhibit.

Unloading the Head and Neck of Quetzalcoatlus

Quetzalcoatulus head being unloaded.

The head of a life-size Quetzalcoatlus model being unloaded at the Field Museum (Chicago).

Picture Credit: (c) Field Museum, photo by John Weinstein

A Flock of Pterosaurs

The flock of pterosaurs will give visitors a lifelike look at the animals that shared the Mesozoic with the dinosaurs.  They’ll also serve as a way-finding tool from Stanley Field Hall up to the rest of the dinosaurs in the permanent exhibition – “The Griffin Halls of Evolving Planet”.  The life-size pterosaurs and the thirty-seven-metre-long Titanosaur will be displayed amongst a series of hanging gardens, as staff at the Field Museum prepare to commemorate the institution’s 125th anniversary.

Commenting on the new exhibits, Field Museum president Richard Lariviere stated:

“Our goal as an institution is to offer visitors the best possible dinosaur experiences and we want that to start right when visitors first enter Stanley Field Hall.  The new hanging gardens and the flock of pterosaurs will take our visitors back to the age of the dinosaurs and will complement the new Titanosaur.”

The Body of a Giant Quetzalcoatlus is Unloaded

Unloading Quetzalcoatlus.

Unloading a giant pterosaur.

Picture Credit: (c) Field Museum, photo by John Weinstein

Rhamphorhynchus, Pteranodon and Quetzalcoatlus

The pterosaur replicas include nine hawk-sized, long-tailed replicas of the Jurassic flying reptile Rhamphorhynchus, two Pteranodon figures and two huge replicas of Quetzalcoatlus.  Pteranodon and Quetzalcoatlus are associated with Upper Cretaceous strata.  Flying reptiles from the Pteranodon genus were thought to have been the largest flying vertebrates that ever existed, that was until 1975, when the much larger azhdarchid Quetzalcoatlus was scientifically described.

Manhandling a Pterosaur Replica (P. sternbergi)

Unloading a Pteranodon.

A life-size Pteranodon replica is unloaded.

 

Picture Credit: (c) Field Museum, photo by John Weinstein

Senior Exhibitions Project Manager Hilary Hansen exclaimed:

“The pterosaurs are nothing short of amazing.  Since Stanley Field Hall is such a massive room, we had the opportunity to add a Titanosaur and an entire flock of pterosaurs.  It’ll really transform the space.”

The models were created by Blue Rhino, under the supervision of the scientists at the Field Museum, the brief was to create the most up-to-date and scientifically accurate figures possible.

Pteranodon Taken up the Stairs

Taking Pteranodon into the museum.

Carrying Pteranodon up the steps.

Picture Credit: (c) Field Museum, photo by John Weinstein

Wingspans the Length of a Bus

The giant Quetzalcoatlus replicas really help to convey the size and scale of these magnificent reptiles.  The wingspan of the models is a little under twelve metres, that’s about as long as a school bus!  The skulls of these types of pterosaur are immense.  Azhdarchid pterosaurs like Quetzalcoatlus had the largest skull of any terrestrial vertebrate.

The Huge Head of a Quetzalcoatlus Replica

Carrying the head of a replica Quetzalcoatlus.

Carrying the head of Quetzalcoatlus, it certainly is a team effort.

Picture Credit: (c) Field Museum, photo by John Weinstein

 

 

31 05, 2018

Uruguay’s First Pterosaur

By | May 31st, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Uruguay’s First Pterosaur

A team of international scientists writing in the academic publication “The Journal of South American Earth Sciences”, have reported the discovery of the first pterosaur fossils known from Uruguay.  The fossil material representing a fragment of jaw with associated teeth, is believed to represent a new species of Ctenochasmatidae pterosaur.  Ctenochasmatids are geographically widespread with fossils reported from the United States, China, southern Germany, Argentina and England.  The fossils ascribed to this family of short-tailed pterosaurs have a large temporal range, from the Late Jurassic transitioning through to the Early Cretaceous.

Views of the Fragmentary Fossil Material (Rostrum)

Ctenochasmatid rostrum from Uruguay.

The first pterosaur fossils from Uruguay.

Picture Credit: The Journal of South American Earth Sciences

Buck-Toothed Pterosaur

The fossil comes from the Tacuarembó Formation, which is believed to represent deposits laid down as the early Atlantic Ocean opened up.  The strata largely consists of  sediments deposited in a terrestrial, near-shore environment.  The orientation of the tooth sockets and the preserved tooth base suggests that the conical teeth were pointed out sideways and forwards.  This may have been an adaptation for capturing slippery prey such as small fish.  This family of small pterosaurs exhibit a variety of different shaped mandibles, although fragmentary, the researchers have identified that the fossil jaw widens towards the tip (anterior portion), the shape of the jaw and its size corresponds to jaws of known ctenochasmatids, specifically the subfamily Gnathosaurinae.

Different Jaw Types within the Ctenochasmatidae

Ctenochasmatid mandible variation.

Ctenochasmatid mandibles.

Picture Credit: Wellnhofer, Howse et al from Witton

The picture shows mandible variation within the Ctenochasmatidae (A) Ctenochasma elegans seen from below, (B) Plataleorhynchus streptorophodon as viewed from below and (C), the skull of Gnathosaurus subulatus (viewed from underneath).  The dentition and the shape of the mandibles suggest adaptations for catching and consuming different types of prey.

Dating the Geological Formation Thanks to a Shark

The Tacuarembó Formation has proved very difficult to date, as the fossils found in the strata were not that easy to compare to fossils found in other rocks.  Despite, an abundance of bone fragments representing a range of creatures, including Theropod dinosaurs, the Tacuarembó Formation lacked helpful biostratigraphic indicator fossils to assist with relative dating.  This changed with the discovery of numerous teeth and a single dorsal spine which was assigned to the Hybodont shark Priohybodus arambourgui.  Fossils of this primitive shark are known from the Arabian Peninsula as well as Africa and the strata associated with these fossils has permitted more accurate dating to occur.  Thanks to this shark, the authors of this new paper can state that the pterosaur fossil material comes from a fossiliferous horizon no older than the Late Jurassic.  As such, the Uruguayan pterosaur remains represent the oldest ctenochasmatid found in South America known to science.

29 05, 2018

Could We Have Got Pterosaurs All Wrong?

By | May 29th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

New Research Challenges Traditional View of Pterosaur Flight

Take a look at a picture of a pterosaur flying and you will see that most illustrations and life-reconstructions of these reptiles depict them travelling through the air with their hind limbs trailing behind them and their back legs wide apart.  However, a new study undertaken by scientists from Brown University (Rhode Island) and the University of California (Berkeley), suggests that we have got this all wrong, pterosaur joints did not permit them to fly with their hind limbs splayed far apart.

Pterosaurs in the Air – But Have we got Their Hind Limbs in the Wrong Position?

Pterosaurs of the Late Cretaceous (Morocco).

Six new species of Pterosaur have been recently identified from Moroccan fossils but if we depict them flying, the convention is to show the hind limbs spread far apart.

Picture Credit: John Conway

We Look at the Bones, But What About the Ligaments?

Flying with the hind limbs splayed out, is a posture adopted by most bats when they take to the air.  Ever since the first flying reptiles were described and illustrated, these Archosaurs have been depicted in the same way.  However, this new research, published in the Proceedings of the Royal Society B (biology), suggests that ligaments would restrict joint movement and pterosaurs and the volant dinosaurs such as Microraptor, could not have flown in the same way as bats.

Lead author of this study, Armita Manafzadeh, a PhD student at Brown University commented:

“Most of the work that’s being done right now to understand pterosaur flight relies on the assumption that their hips could get into a bat-like pose.  We think future studies should take into account that this pose was likely impossible, which might change our perspective when we consider the evolution of flight in pterosaurs and dinosaurs.”

The “Classical” Pterosaur Flying Posture

Investigating the flying posture of the Pterosauria.

The “bat-like” posture of the hind limbs of pterosaurs, may not have been anatomically possible.

Picture Credit: Armita Manafzadeh

The study undertaken in collaboration with Kevin Padian (University of California), attempted to infer the range of motion of joints in a way that takes into account the soft tissues such as ligaments surrounding the joint.  Usually, soft tissue such as ligament and cartilage does not fossilise, so palaeontologists have to work out joint motion from just the bones alone.  The pair of scientists set out to examine the joint movement of modern dinosaurs – birds, to test the extent to which ligaments influence joint motion.

Chickens at a Grocery Store

Student Manafzadeh explained that the idea started with grocery store chickens:

“If you pick up a raw chicken at the grocery store and move its joints, you’ll reach a point where you will hear a pop.  That’s the ligaments snapping, but if I handed you a chicken skeleton without the ligaments, you might think that its joints could do all kinds of crazy things,  So, the question is, if you were to dig up a fossil chicken, how would you think its joints could move and how wrong would you be?”

Quetzalcoatlus – A Giant Pterosaur Takes to the Air (Note the Splayed Out Back Legs)

Quetzalcoatlus takes to the air

Quetzalcoatlus takes to the air.

Picture Credit: Everything Dinosaur

Dead Quails and X-ray Images

Chickens may be easy to acquire, but for this scientific study, dead quails were used in order to assess joint mobility in a three-dimensional way, rather than just referring to the bones.  Birds are the closest living relatives to the extinct pterosaurs and the non-avian dinosaurs.  Birds (Aves), the Pterosauria and the Dinosauria are members of the Archosauria clade.  This clade is  usually divided into two distinct branches, on one branch (Crurotarsi), are the crocodilians and their ancestors plus several other extinct lineages such as the phytosaurs.  The second branch (Avemetatarsalia) groups all the reptiles more closely related to birds than crocodilians.  A sub-group of the Avemetatarsalia is the Ornithodira, which specifically nests the Pterosauria and their ancestors and the Dinosauria and their ancestors, plus the descendants of dinosaurs – birds, together.  Hence, the use of quail limbs to assess the range of movement and joint mobility.

The skin and muscle surrounding the joints was cut away and once the hip joints were exposed, the scientists manipulated them taking X-ray images to assess the likely range of motion.  By doing this, they could determine the exact positions of the bones in poses where the ligaments restricted and then prevented further joint movement.

Mapping Out the Joint Movements of Ornithodirans

This technique enabled Manafzadeh to map out the range of motion of the quail hip with ligaments attached.  She then compared this range of motion to what was inferred when the bones were considered in isolation.  For the bones-only poses, Manafzadeh used traditional criteria that palaeontologists often employ — stopping where the two bones hit each other and when the movement pulled the thigh bone out of its socket.

This experiment revealed that over 95 percent of the joint positions that seemed plausible with bones alone were actually impossible when the ligaments were attached.

Mapping Out the Range of Motion in Quail Hips

Mapping the movement of Archosaur limbs.

Mapping the range of movement in quail hind limbs to assess the movement of Ornithodiran limbs.

Picture Credit: Armita Manafzadeh

The Implications for Pterosaurs and the Maniraptora

The team’s next move was to calculate how the range of motion in living birds might correlate to the range of motion expected for extinct pterosaurs and those members of the Maniraptora, such as Microraptor that are believed to have been able to fly.  The assumption has long been that these creatures flew in a similar way to bats.  That is partly because the wings of pterosaurs were made of skin and supported by an elongated fourth finger, which is superficially similar to the wings of bats.  Bat wings are also connected to their hind limbs, which they splay out widely during flight. Many palaeontologists, Manafzadeh says, assume pterosaurs and four-winged dinosaurs did the same.  But this new study suggests that pose was impossible.

In quail, a bat-like hip pose seemed possible based on bones alone, but outward motion of the thigh bone was inhibited by one particular ligament, a ligament that’s present in a wide variety of birds and other reptiles related to the Pterosauria.  Consequently, in the absence of extraordinary evidence to the contrary, this analysis casts doubt on the “bat-like” hip pose traditionally inferred for pterosaurs and basal Maniraptorans and underscores the point that reconstructions of joint mobility based on manipulations of bones alone can be misleading.

To achieve a “bat-like” flying posture, the ligament would have to stretch 63 percent more than the quail ligament can, the implication is that we have been illustrating flying reptiles and flying dinosaurs all wrong.

A Model of a Volant Dinosaur (Microraptor)

A Microraptor flight model.

Up, up and away!  A model of the four-winged dinosaur Microraptor in flight, note the splayed-out position of the back legs.

Picture Credit: Solent

In addition to challenging traditional views about flight in pterosaurs and early birds, the research also provides new ways of assessing joint mobility for any joint of any extinct species by looking at its living relatives.

The scientific paper: “ROM Mapping of Ligamentous Constraints on Avian Hip Mobility: Implications for Extinct Ornithodirans” by Armita R. Manafzadeh, Kevin Padian published in the Proceedings of the Royal Society B

Everything Dinosaur acknowledges the assistance of a press release from Brown University in the compilation of this article.

28 05, 2018

Fossil Flakes and Dinosaur Dandruff

By | May 28th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

Dinosaur and Early Bird Dandruff

A team of international scientists led by researchers from University College Cork (Ireland), have discovered the fossilised remains of skin flakes from feathered dinosaurs and primitive birds that lived during the Early Cretaceous.   The flakes of skin, preserved amongst the plumage of the feathered creatures, has provided evidence on how dinosaurs shed their skin.  Unlike many reptiles alive today, animals such as lizards and snakes, which shed their skin as a single piece or as several large pieces, it seems that basal birds and non-avian dinosaurs shed small epidermal flakes just like modern birds and mammals and that includes us with our dandruff.

Preserved Soft Tissue Evidence – Flakes of Skin in Maniraptoran Dinosaurs and the Basal Bird Confuciusornis

Fossils of shed dinosaur skin and a basal bird (Confuciusornis).

Phosphatised soft tissues in non-avian Maniraptoran dinosaurs and a basal bird.

Picture Credit: Nature Communications

The photographs above (labelled a to h), show scanning electron microscope generated images of tissue in the Early Cretaceous Aves C. sanctus (a,e and f), the dromaeosaurid Sinornithosaurus (S. millenii) in photographs c and h, along with the Therizinosaur Beipiaosaurus (B. inexpectus), photos b and g.  The photograph labelled d, is a view of epidermal flakes preserved in association with the fossilised remains of Microraptor, which along with Sinornithosaurus is believed to have been capable of flight or at least gliding.  Studying the constituents of flakes of dinosaur skin, which come from animals that might have been volant, is very important.  Palaeontologists can compare these flakes to living birds which are capable of powered flight.  These flakes, in turn can be examined in relation to the flakes of terrestrial feathered dinosaurs such as Beipiaosaurus.  Any differences in the composition of these flakes might provide scientists with further information on the aerial abilities of dinosaurs such as Microraptor and Sinornithosaurus.

The scientists include researchers from the Chinese Institute of Vertebrate Palaeontology and Palaeoanthropology, Bristol University, Linyi University (China), the Open University as well as Queen Mary University (London) and the University College Dublin (Ireland).   They studied the fossil cells and dandruff from a range of Early Cretaceous Theropods and compared the skin flakes to those of living, extant birds.

Lead author of the research, Dr Maria McNamara (University College Cork), stated:

“The fossil cells are preserved with incredible detail,  right down to the level of nanoscale keratin fibrils.  What’s remarkable is that the fossil dandruff is almost identical to that in modern birds – even the spiral twisting of individual fibres is still visible.”

Getting to Grips with Corneocytes

The scientists used a scanning electron microscope (SEM), to examine the beautifully preserved, but microscopic fossilised fragments of skin associated with three feathered dinosaur specimens (Microraptor, Beipiaosaurus and Sinornithosaurus) and one Early Cretaceous bird Confuciusornis (Confuciusornis sanctus).  All of these fossils are associated with the Jehol biota of north-eastern China.

A Pair of Fossilised Confuciusornis (Liaoning Province) Showing the Two Known Body Plans for these Ancient Birds

Confuciusornis fossil birds.

A pair of Confuciusornis fossil birds (Liaoning Province).

Just like our own flakes of skin, our dandruff, the fossil flakes consist of tough cells known as corneocytes.  These cells are full of protein fibres (keratin), such was the quality of preservation that the SEM analysis was able to identify bundles of these fibres and even to hone in on single strands.

Scanning Electron Micrographs of Skin Flakes Associated with C. sanctus

Fossilised skin flakes of Confuciusornis.

Ultrastructure of the soft tissues in Confuciusornis.

Picture Credit: Nature Communications

The photographs (above) show highly magnified images of the skin flakes associated with Confuciusornis.  Closely packed polygons can be observed (a and b), whereas (c) shows a detailed view of the polygons and the first signs at this magnification of the bundles of fibrous keratin.  The drawing (d) interprets the bundles as more darkly shaded areas in the central part of each polygon.  Photograph (e) shows the area that was more closely observed (f and g) indicating the presence of fibres, whereas, (h) shows the fibrous bundle associated with a skin flake in an extreme close-up view.  Helical coiling of the tiny fibres is shown (picture i) and photographs j and k show polygons having been deformed by some form of stretching.

These structures were then compared to the flakes of skin associated with living birds, in this case, male specimens of Zebra Finches (Taeniopygia guttata) and the Java Sparrow (Lonchura oryzivora).  In addition, the fossil evidence was compared to the moulted, downy feathers of a male American Pekin Duck (Anas platyrhynchos domestica).

Clues About Dinosaur Metabolism

This research suggests that this ability to constantly shed skin evolved sometime in the late Middle Jurassic, around the same time as a host of other skin features evolved.  The feathered epidermis of dinosaurs acquired many, but not all, anatomically modern attributes close to the base of the Maniraptora clade.

Dr McNamara explained:

“There was a burst of evolution of feathered dinosaurs and birds at this time, and it’s exciting to see evidence that the skin of early birds and dinosaurs was evolving rapidly in response to bearing feathers.”

Co-author, Professor Mike Benton (Bristol University), commented:

“It’s unusual to be able to study the skin of a dinosaur, and the fact this is dandruff proves the dinosaur was not shedding its whole skin like a modern lizard or snake but losing skin fragments from between its feathers.”

Corneocytes in Living Birds

Corneocytes in living birds

Corneocytes in extant birds.

Picture Credit: Nature Communications

The four photographs above, show scanning electron micrographs of shed skin flakes in living birds.  Note the polygonal structure (a), which is reminiscent of the shapes seen when the corneocytes of extinct dinosaurs and birds were studied.  Photograph (b) shows a central depression in the cell associated with a pycnotic nucleus, whilst photographs (c and d) show skin flakes stuck to the bird’s feathers.

Modern birds have very fatty corneocytes with loosely packed keratin, which allows them to cool down quickly when they are flying for extended periods.  The corneocytes in the fossil dinosaurs and birds, however, were packed with tightly bundled keratin, suggesting that the extinct creatures didn’t get as warm as modern birds, presumably because they couldn’t fly at all or for as long.  This suggests that Confuciusornis did not fly that well, if probably flew in short bursts, but may not have been capable of making prolonged flights.  The lack of fatty corneocytes in those dinosaurs which are thought to have had some aerial ability (Microraptor and possibly Sinornithosaurus), sheds doubt on whether they were truly volant.

Could Some Dinosaurs Like Microraptor Fly?

Microraptor dinosaur model.

A member of the Dromaeosauridae sub-family the Microraptorinae, but could these dinosaurs fly?  The absence of fatty corneocytes suggests a lower metabolism than with extant birds..

Picture Credit: Everything Dinosaur

Everything Dinosaur acknowledges the assistance of a press release from the University College Cork (Ireland) in the compilation of this article.

The scientific paper: “Fossilised Skin Reveals Coevolution with Feathers and Metabolism in Feathered Dinosaurs and Early Birds” by Maria E. McNamara, Fucheng Zhang, Stuart L. Kearns, Patrick J. Orr, André Toulouse, Tara Foley, David W. E. Hone, Chris S. Rogers, Michael J. Benton, Diane Johnson, Xing Xu and Zhonghe Zhou published in Nature Communications.

25 05, 2018

How Birds Survived the Cretaceous Mass Extinction Event

By | May 25th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

Ground Dwelling Birds Survived Asteroid Strike

One of the fascinating conundrums about the end Cretaceous extinction event is how did the avian dinosaurs (birds) survive, but their very close cousins the non-avian dinosaurs, animals such as Tyrannosaurus rex, Triceratops and Edmontosaurus fail to make it through this calamitous time in Earth’s history?  A team of international researchers, writing in the journal “Current Biology” have put together a fascinating explanation as to why we have birds today, but no other Theropods, or indeed any other representatives of the Dinosauria.

With the extra-terrestrial impact event some 66 million and 38 thousand years ago (plus or minus 11,000 years), the ecosystems on our planet were devastated.  Whether this single, huge impact was the sole cause of the mass extinction or whether this was the final “coup de grâce” is debatable, however, life would never be the same again.

Using a variety of data sources, the team, which included scientists from the University of Bath, the Denver Museum of Nature and Science, Yale University and the Field Museum amongst others, have pieced together what the impact event meant for the Aves.  Their scientific paper suggests that the only kinds of birds to survive the Cretaceous-Palaeogene (K-Pg) extinction were ground- dwellers.

How Our Feathered Friends Survived the Cretaceous-Palaeogene Extinction Event

Ground-dwelling birds survived the extinction event.

Ground-dwelling birds survived the K-Pg extinction event.

Picture Credit: Phillip Krzeminski

Why Did the Birds Survive?

A number of ideas and theories have been proposed to help explain why the birds are around today, but the non-avian dinosaurs are not.  Recently, Everything Dinosaur published an article on a piece of research that suggested that seed-eating may have contributed to the survival of birds during this devastating time in the history of our planet.

To read the article: Seed Eating May Have Helped the Birds Survive

Commenting on the scientific paper, lead author Daniel Field of the Milner Centre for Evolution (University of Bath) stated:

“We drew on a variety of approaches to stitch this story together.  We concluded that the devastation of forests in the aftermath of the asteroid impact explains why tree-dwelling birds failed to survive across this extinction event.  The ancestors of modern tree-dwelling birds did not move into the trees until forests had recovered from the extinction-causing asteroid.”

The Collapse of Forests

The scientists analysed the plant fossil record and identified that the world’s woodlands and forests were virtually wiped out by the extra-terrestrial impact.  Huge forest fires would have raged in the immediate aftermath of the impact and it is likely that much of the world had to endure a period of extensive “acid rain” as a result of the catastrophic event.  In the months, or maybe even tens of years afterwards, our planet could have been blanketed in a cloud of dust and ash.  This would have blocked out the sun and led to the collapse of food chains which relied on photosynthesising plants.

The Impact Event Had Consequences for Virtually All Life on Earth

Earth impact event.

Cataclysmic impact event that led to the extinction of the non-avian dinosaurs but not all the avian dinosaurs.

Picture Credit: Don Davis (Commissioned by NASA)

The scientists look at the record of fossil pollen and spores to assess the types of flora present and how quickly, ferns, flowering plants (angiosperms) and other types of flora recovered after the extinction event.

Plotting the Turnover of Different Types of Flora from Pollen and Spore Counts

Flora turnover at the K-Pg boundary.

Floral turnover evidenced by changes in relative abundance of common pollen taxa across the K-Pg boundary.

Picture Credit: Current Biology with additional annotation by Everything Dinosaur.

The diagram (above), plots the palynological record of the John’s Nose Section in North Dakota, a series of sequential strata laid down before, during and after the extinction event.  It helps to plot the demise of different types of plant and their recovery (floral turnover), as evidenced by changes in relative abundance of common pollen taxa across the K-Pg boundary.  Note, the “fern spike” recorded not long after the extinction event, ferns are usually the first type of plant to recover from natural disasters today, as evidenced by their ability to re-populate areas destroyed following volcanic activity.

Evolutionary Relationships of Living Birds

The research team examined the evolutionary relationships of extant birds and their ecological habits to map how bird ecology has changed over time.  The data revealed that the most common ancestor of all living birds, all the bird lineages that survived the K-Pg extinction event, most likely were ground-dwellers.  In contrast, many Aves that lived at the end of the age of dinosaurs (and there were lots of them), exhibited tree-dwelling, arboreal habits.  These species did not survive the mass extinction event and therefore they have no direct living descendants around today.

Daniel Field added:

“Today, birds are the most diverse and globally widespread group of terrestrial vertebrates, there are nearly 11,000 living species.  Only a handful of ancestral bird lineages succeeded in surviving the K-PG mass extinction event 66 million years ago and all of today’s amazing living bird diversity can be traced to these ancient survivors.”

The researchers conclude that their findings shed light on the fundamental influence major events in the history of our planet have on the evolution of living things.  The team hope to build on this initial research and to explore the timing of the recovery of the vegetation and to develop a better understanding of the early radiation of the birds.  After all, those lucky survivors inherited a brave new world, devoid of non-avian dinosaurs and many other terrestrial and marine organisms too.

The scientific paper: “Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction” by Daniel J. Field, Antoine Bercovici, Jacob S. Berv, Regan Dunn, David E. Fastovsky, Tyler R. Lyson, Vivi Vajda and Jacques A. Gauthier published in the journal Current Biology.

23 05, 2018

Dinosaurs in Ermine

By | May 23rd, 2018|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Main Page|0 Comments

Dinosaurs in Ermine

An interesting headline featured on the front of a national newspaper here in the UK.  It was spotted as an Everything Dinosaur team member went past a newspaper vendor this morning.

Intriguing Headline – Dinosaurs in Ermine

A dinosaur themed headline.

A headline from an English newspaper.  Don’t worry it is not a report on a new dinosaur fossil discovery!

The headline certainly caught our attention.  However, it was not a report on an amazing pseudo-mammal dinosaur fossil find, after all, palaeontologists have only now got some members of the public to accept the idea of dinosaurs with feathers.

22 05, 2018

A Feature of the Archosauria – (Part 2)

By | May 22nd, 2018|Animal News Stories, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

Labelling the Fenestrae in a Diapsid Skull

Recently, Everything Dinosaur posted up a picture of the skull of a large gharial and discussed the teeth located in distinct sockets, an anatomical trait characteristic of that great group of reptiles the Archosaurs (Archosauria).  Today, we complete this very brief look at the Archosaurs by labelling the fenestrae (holes) in the skull that identify the gharial, all crocodiles and their close relatives, including the dinosaurs, that are classified as diapsid reptiles.

The Skull of the Gharial with the Eye Socket (Orbit) and Fenestrae Labelled

A gharial skull with the fenestrae and eye sockets labelled.

Labelling the skull of a diapsid reptile.

Picture Credit: Everything Dinosaur

The gharial (a long-snouted, crocodilian), skull is from the Grant Museum of Zoology and Comparative Anatomy (London).  In the photograph (above), we have labelled the holes (fenestrae) in the skull, the left lateral side of the skull is seen and the lower (inferior) temporal fenestra has been labelled.  Behind the large orbits (eye sockets), on the top of the skull, the pair of upper (superior) temporal fenestrae have been labelled.  Please note each of the holes (singular) is termed a fenestra, but the plural is fenestrae.

The diapsid reptiles are an extremely diverse group that contains a number of extinct kinds of reptile as well as snakes, lizards, turtles, the last surviving member of the ancient order Ryhnchocephalia – the tuatara, crocodiles, dinosaurs and birds.  The last three listed, crocodiles, dinosaurs and birds are of course Archosaurs, and the Archosauria are characterised by a number of anatomical features including the two pairs of skull fenestrae.

The holes in the skull probably evolved to permit larger muscle attachments for the jaws, giving these animals a stronger bite.  The mouth could also be opened wider, a definite advantage of you are having to bolt down lumps of flesh or to cram into your stomach large amounts of nutritionally poor vegetation.

To read our article about another feature of the Archosauria – tooth sockets: A Feature of the Archosauria (Part 1)

21 05, 2018

A Feature of the Archosauria – (Part 1)

By | May 21st, 2018|Animal News Stories, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

Examining Teeth in Sockets – Crocodilians (Archosauria)

Team members at Everything Dinosaur were given the opportunity to examine the skull of a large Gharial recently.  The gharial (Gavialis gangeticus), has evolved a long, elongated snout and specialises in catching fish (piscivore).  These once widespread and diverse members of the Gavialidae are extremely rare in the wild.  They are restricted to a few fragmentary populations scattered amongst the river systems of the northern parts of the Indian sub-continent.

Examining the Skull of a Large Gharial

The skull of a gharial.

The skull of a gharial from the Grant Museum of Zoology (London).

Picture Credit: Everything Dinosaur

The skull of this crocodilian portrays several characteristics that identifies it as a member of the Archosauria, the same clade of reptiles that includes dinosaurs, pterosaurs and birds.  The skull has a number of holes in it (fenestrae), these holes establish it as a member of the diapsid, one of three main groups of reptiles that can be distinguished from each other by the presence or absence of such fenestrae and their number.  Establishing shared characteristics between different species (synapomorphies), is the standard model for classifying organisms.   These shared characteristics, came from a shared, common ancestor.  Essentially, taxonomists are looking to identify similarities and differences.  The number of holes in the skull is one of the synapomorphies that establishes this gharial as a member of the Archosaurs (ruling reptiles).

Teeth in Sockets

Another synapomorphy shared amongst the Archosauria, (although derived members of this group such as the birds have subsequently lost this trait), can be seen in the jaw.  The teeth of the gharial are set in sockets.  These sockets are termed alveoli (singular alveolus).  Being strongly anchored in a bony socket allows the tooth to withstand greater forces.  It is less likely to be lost during predation and feeding.  This enabled many of the early Archosaurs to evolve powerful jaws, capable to tacking struggling prey or coping with tough, fibrous vegetation.  This evolutionary trait may help to explain their success.

On the Skull of the Gharial – the Teeth Sockets can be Easily Seen

Teeth in sockets - characteristic of the Archosaurs.

A defining characteristic of the Archosauria – teeth in sockets.

Picture Credit: Everything Dinosaur

17 05, 2018

Largest Pterosaur Mandible Ever Found

By | May 17th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

Giant Romanian Pterosaur Hints at Ecological Niches within the Azhdarchidae

Transylvania back in the Late Cretaceous was a very scary place.  This central part of Romania, might be associated with vampires today, thanks mainly to Bram Stoker’s Gothic horror “Dracula”, but towards the end of the Mesozoic, much of Europe was under the sea, rising above the remnants of the once mighty Tethys was an island and real monsters lurked there.

The island is known as Hateg Island and it was a very strange place indeed.  There were dinosaurs, but the apex predator was an animal capable of flight, just like the blood-sucking protagonist from the 1897 novel.  Huge azhdarchid Pterosaurs stalked Hateg Island and an international team of researchers writing in the academic journal “Lethaia”, report finding the largest Pterosaur jawbone known to science.

Huge Azhdarchid Pterosaurs Stalked Hateg Island

A group of azhdarchid Pterosaurs hunting.

Some Pterosaurs were as tall as a giraffe.  These were the real monsters of Transylvania.

Picture Credit: Mark Witton

Niche Partitioning Amongst Giant Flying Reptiles

Pterosaurs in the family Azhdarchidae, represent the largest flying animals to have ever existed, with the longest skulls of any terrestrial tetrapod.  They were globally distributed, with azhdarchid fossils having been reported from every continent except Antarctica.  However, despite their huge size (wingspans in excess of ten metres have been estimated for several species), their fossil record is extremely poor, with most species, even giants such as Quetzalcoatlus, known from a few fragmentary, mere scraps of bone.

The mandible fossil is part of the largest Pterosaur mandible (lower jaw) found to date.  The fossil was collected from Maastrichtian continental deposits near Vălioara in the Hațeg Basin, Romania.  The azhdarchid Pterosaur Hatzegopteryx thambema is known from these Upper Cretaceous sandstone deposits (Red Cliffs), but this new fossil cannot be confidently referred to H. thambema due to the absence of overlapping skeletal elements.  In short, the lower jaw fossil of H. thambema which would correspond to the newly described mandible has not been found.

It has been suggested that this, as yet, unnamed Hateg Pterosaur, may have been a relatively stocky, heavy-set flying reptile, with a short neck and a huge head.  It is reported that comparisons with previously described large‐sized azhdarchid mandibles indicate a certain degree of morphological and probably ecological disparity within the Azhdarchidae.  Different giants may have occupied slightly different niches in the ecosystem, in this way they could avoid direct competition.  The dividing up of resources in this way is referred to as niche partitioning.

A View of the Red Cliffs in Romania (Location of Fossil Find)

The steep cliffs of the dig site (Sebes, Romania).

The Red Cliffs dig site near Sebeș in Romania.  These sandstones represent continental sandstone deposits from the end of the Cretaceous.

Picture Credit: Mátyás Vremir

A Six to Eight Metre Wingspan

Lead author of the study, published in “Lethaia”  an international journal of palaeontology and stratigraphy, Mátyás Vremir of the Transylvanian Museum Society stated:

“It is not the largest Pterosaur ever found, but it is the largest mandible recovered to date, with a reconstructed length of 110 to 130 centimetres.  This might indicate a very large size Pterosaur, possibly 8 to 9 metres in wingspan.”

A trio of enormous Pterosaurs are associated with the Hateg Formation.  With the discovery of this partial mandible, Transylvania can claim to be a “hot spot” for super-sized flying reptiles.  It had been thought that towards the end or the Cretaceous, the Pterosauria were in decline, however, a paper published in March this year identified a Late Cretaceous ecosystem in Morocco with at least six coeval species of Pterosaur including the presence of two azhdarchid Pterosaurs, one of whom could have been a giant.

To read our article about the Moroccan fossil discovery: Pterosaurs more diverse than previously thought

Fragmentary remains of another azhdarchid Pterosaur from Romania, uncovered in 2009, which have yet to be formally described, confirm that Hateg Island was home to a variety of giant flying reptiles.  The fossils associated with this Pterosaur have been nicknamed “Dracula” by scientists.

A Piece of the Pterosaur Fossil Bones Nicknamed “Dracula” Eroding Out of a Cliff

A fragment of Pterosaur fossil bone (Mátyás Vremir).

A piece of Pterosaur fossil bone eroding out of the cliff.

Picture Credit: Mátyás Vremir

Specimen Number LPB (FGGUB) R.2347

The mandible fossil, part of the back of the lower jaw exhibits anatomical traits that are present in both azhdarchid and tapejarid Pterosaurs.  This suggests that the specimen (LPB (FGGUB) R.2347), comes from an animal that had a more basal position within the Azhdarchidae family.  The researchers conclude that this bone shares a number of features with the smaller azhdarchoid Bakonydraco galaczi ,which is known from much older Cretaceous deposits in Hungary.

Vremir added:

“Except for a few scraps, after more than a century of fossil collecting in Transylvania, nothing was known about Pterosaurs until the last 16 years.  In the past 10 years, the picture changed substantially and over 50 fossil specimens were collected from various sites.”

Azhdarchid Pterosaur Wrist Bone

Azhdarchid Pterosaur wrist bone (Hateg Formation).

Azhdarchid Pterosaur wrist bone.

Picture Credit: Mátyás Vremir

The huge, partial mandible, the only part of the new animal found so far, was originally dug up in the Hateg region of Transylvania in 1978, but at the time it wasn’t recognised as a Pterosaur fossil. Vremir and co-author of the scientific paper, Gareth Dyke, (University of Debrecen, Hungary), were visiting Bucharest’s fossil collection in 2011 and made the connection.

Flightless Giants

Using analogies such as the Elephant Bird of Madagascar and the Dodo from Mauritius, island life can lead to volant creatures evolving in very different directions.   The Dodo and the Elephant bird were descended from birds that could fly, but once established on an island, with few predators, these birds adopted a ground-dwelling existence and over many subsequent generations they lost the ability to take to the air.  Mátyás Vremir and his colleagues speculate that some of the very largest Hateg Pterosaurs may have taken a similar evolutionary route.  Perhaps as young animals they could fly, a very good way to avoid terrestrial predators, but as they grew and became adults reaching a size whereby they were unlikely to be attacked by other animals, they were unable to fly.

Everything Dinosaur team members are aware that are number of papers are currently being prepared that explore this intriguing idea further.

The scientific paper: “Partial Mandible of a Giant Pterosaur from the Uppermost Cretaceous (Maastrichtian) of the Hațeg Basin, Romania” by Mátyás Vremir, Gareth Dyke, Zoltán Csiki‐Sava, Dan Grigorescu and Eric Buffetaut.

16 05, 2018

“Simple but Elegant” Solution to Dinosaur Egg Incubation

By | May 16th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

How to Brood Your Eggs When You Weigh More Than a Tonne

The question of how dinosaurs incubated their eggs without crushing them has been a puzzle ever since the first dinosaur nesting sites were discovered nearly a hundred years ago.  A Canadian-led study has found a link between the radius of the nest of Oviraptorosauria clade members and the body size of the parent.  In research into the nesting habits of Oviraptorosaurs, the scientists discovered that small species laid eggs in clusters, just like many extant birds today.  Much larger species, the giants such as Gigantoraptor, laid eggs in a stacked ring, so that they could keep their eggs close without crushing them with their bodies.

The Larger the Oviraptorosaur the Bigger the Nest Diameter

Small Oviraptorosaurs compared to Large Oviraptorosaurs.

New study suggests a link between the layout of eggs and dinosaur size.

Picture Credit: Masato Hattori

Dedicated Parents

Palaeontologists think that there were many different nesting strategies adopted by the diverse dinosaurs, but this study focused on the incubation of the eggs associated with Oviraptorosaurs, a group of very bird-like Theropods that are known from the Late Cretaceous of North America and Asia.  It is very likely that these dinosaurs were dedicated parents and that they spent many weeks, incubating their eggs by sitting on the nest.  How much parental care dinosaurs showed to their offspring remains an area of considerable controversy, but just like birds today, dinosaurs probably adopted a range of altricial, semi-precocial and precocial strategies* when it came to their young.

Lead author of the study, published in the Royal Society journal “Biology Letters”, Darla Zelinitsky, (Assistant Professor of Geoscience at the University of Calgary, Alberta, Canada), commented:

“In the largest Oviraptorosaur clutches [Macroelongatoolithus], the central opening represents most of the total clutch area, likely allowing giant-sized species to rest their entire weight on this area so as not to crush the eggs.”

Forty Fossil Nests Studied

The research team, which included a former PhD student of Darla’s, Kohei Tanaka (Nagoya University, Japan), studied and measured around forty Oviraptorosauria fossil nests, most of which come from China, but fossils from North America and from elsewhere in Asia, were included in the study.  The smallest nests revealed eggs laid in clusters, but the largest nests, associated with the largest of the Oviraptorosaurs, were up to 3.3 metres wide, took on a ring shape with a large, flat, central area, presumably where the adult animal sat.

A spokesperson from Everything Dinosaur commented:

“Some of the largest nests associated with the Oviraptorosauria are so wide that a smart car could be parked in the space in the middle, the metaphor is quite appropriate given that a number of giant species have been named.  Dinosaurs like the colossal caenagnathids Gigantoraptor or Beibeilong may have been much heavier than a smart car, yet it is thought that these huge animals had to sit on their nests and incubate the eggs.”

The Oogenus Macroelongatoolithus

Just like dinosaur bones, tracks and the fossilised remains of dinosaur eggs can lead to the establishment of a new genus or species.  Footprints and other trace fossils that are given a formal scientific name are characterised by the epithet “ichno”, whereas, egg fossils are characterised by the epithet “oo”, the root of which is “oolithus” from the Latin meaning “stone egg”.  Numerous dinosaur oogenera have been erected, one of the largest eggs Macroelongatoolithus, some of which measure sixty centimetres in length, are associated with the Oviraptorosauria.

To read Everything Dinosaur’s 2017 blog article about the establishment of a new species of giant Oviraptorosaur from embryos associated with Macroelongatoolithus eggs: Dinosaur Embryo Fossil Leads to New Dinosaur Species

The researchers conclude that the smallest Oviraptorosaurs probably sat directly on the eggs, whereas with increasing body size more weight was likely carried by the central opening, reducing or eliminating the load on the eggs and still potentially allowing for some contact during incubation in giant species.  This adaptation, not seen in birds, appears to remove the body size constraints of incubation behaviour in giant Oviraptorosaurs.

The Ring-shaped Layout of Eggs Associated with a Large Oviraptorosaur

Giant Oviraptorosaur nest.

A nest of a giant Oviraptorosaur.

Picture Credit: Kohei Tanaka (Nagoya University)

Numerous species of Oviraptorosaurs have been named, most of these dinosaurs were relatively small around 2-3 metres in length, however, considerably larger taxa have been identified, giants such as Gigantoraptor erlianensis, which may have reached lengths of more than eight metres and weighed around 1.4 Tonnes.

While most nests have been found in Asia, in particular the Gobi Desert, Zelinitsky conducted research on dinosaur nests found in South Korea and Canada.

Dinosaurs of China 2017.

A Gigantoraptor exhibit, one of the largest feathered dinosaurs known to science.

Picture Credit: Everything Dinosaur

Zelinitsky added:

“It’s a unique structure, no other dinosaurs build their nests in that shape, and no living animals incubate their eggs this way.  I just think it’s really neat that we’re able to say something more about the nesting behaviours and how they changed in these Oviraptorosaur dinosaurs among the various species and species sizes.”

The researchers aren’t sure why these dinosaurs sat on their eggs.  If it was to keep the eggs warm, those dinosaurs that sat in the middle of the ring probably couldn’t transfer heat as effectively as the ones that sat directly on the eggs.  However, these dinosaurs had arms covered with feathers, these “wings” could have helped to shelter the eggs and to protect them as well as providing a warmer surface area to help the eggs maintain an appropriate temperature.

The researchers describe the organisation and egg layout of the nest as a “simple and elegant” solution to the problem of large dinosaurs crushing of their own eggs.

*Altricial and Precocial Nesting Behaviours

Modern birds demonstrate a variety of behavioural responses when it comes to raising their young.  Some bird species like ducks and ostriches have highly precocial young.  The babies are able to vacate the nest and feed themselves within just a few hours of hatching.  Other bird species have a different approach, for example, most of the passerines (song birds), such as wrens, blackbirds and thrushes are helpless when they hatch and rely on their parents to provide food and to keep them warm.  In reality, the Aves (which are very closely related to the extinct Oviraptorosaurs), exhibit a wide range of behaviours.  Altricial and precocial traits tend to be at opposite ends of a spectrum, given the paucity of the fossil record, it is difficult to clarify the development strategy of any extinct species.

The Altricial and Precocial Nesting Behaviour Spectrum

Birds - altricial and precocial behaviours.

Altricial and precocial behaviours in Aves – a spectrum.  It is very likely that a spectrum of nesting behaviours was also exhibited by the Dinosauria.

Picture Credit: Everything Dinosaur

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