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/Palaeontological articles

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

14 01, 2019

Basilosaurus – The Apex Predator

By | January 14th, 2019|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Research Confirms Basilosaurus Was a Top Predator

Readers with a long memory might remember an episode from the BBC “Walking with Beasts” television series that first aired in 2001.  In this sequel to “Walking with Dinosaurs”, the focus was placed upon the evolution of the mammals after the dinosaur extinction.  “Whale Killer”,  which was episode two in the six-part series, told the story of a pregnant Basilosaurus (archaic whale), desperately searching for food to help the calf growing inside her.  Thanks to raids on Dorudon whales and their young, the Basilosaurus is able to successfully give birth and this episode ends with the mother swimming away with her new-born calf following close behind.

An Illustration of the Fearsome Early Toothed Whale Basilosaurus

PNSO Basilosaurus illustration.

An illustration of Basilosaurus.  The human figure provides scale.

Picture Credit: Everything Dinosaur

Analysis of Basilosaurus Stomach Contents

A team of researchers writing in the on-line, academic journal PLOS One, have published the results of stomach content analysis of Basilosaurus specimens from the Late Eocene-aged site at Wadi Al-Hitan in Egypt.  It is confirmed that Basilosaurus fed on smaller whales (juvenile Dorudon atrox) as well as large fish (Pycnodus mokattamensis).  The scientists, which included Manja Voss (Museum für Naturkunde Berlin) and Mohammed Sameh M. Antar from the Egyptian Environmental Affairs Agency, Cairo, state that this is the first direct evidence of Basilosaurus (B. isis) diet.

A Size Comparison Between an Adult Basilosaurus isis and an Adult Dorudon atrox

An adult Basilosaurus compared to an adult Dorudon whale.

Comparing an adult, fifteen-metre-long Basilosaurus isis museum mounted skeleton to a fully grown Dorudon atrox.

Picture Credit: PLOS One/University of Michigan

Basilosaurus – Top of a Tethys Ocean Ecological Pyramid

The Late Eocene Epoch was a time of dramatic change and global extinction.  The once mighty Tethys Ocean was very much reduced, but the first, giant, toothed whales had evolved and the research team cite Basilosaurus isis, the Late Miocene Livyatan melvillei, and the extant Orca (Orcinus orca) as three marine apex predators known from relatively short intervals of time during the Cenozoic.  This research confirms the predator-prey relationship between the two most frequently found fossil whales at the Wadi Al-Hitan location.  Bite marks on the preserved skulls of Dorudon whales suggest predation and not scavenging behaviour by Basilosaurus.

A Photomosaic of a Basilosaurus Specimen (WH 10001)

Basilosaurus scattered remains.

Photomosaic of Basilosaurus isis (WH 10001) from the Gehannam Formation of Wadi Al Hitan.

Picture Credit: PLOS One

The image above shows a photomosaic of a scattered and disarticulated Basilosaurus isis specimen from the Gehannam Formation of Wadi Al-Hitan.  The disarticulation of the fossil skeleton and the scattering suggests disturbance by scavengers and possibly long exposure on the seafloor prior to burial.

The researcher conclude that Basilosaurus was a top apex predator that hunted and ate its prey alive, rather than scavenging for scraps.  If the Wadi Al-Hitan site, represents a calving area for the Dorudon, then this would have made an ideal hunting spot for a hungry Basilosaurus.  The dramatic scenes in episode two of the “Walking with Beasts” television series, have more published scientific evidence to back up the screenplay.

9 01, 2019

When Did Life on Land First Evolve?

By | January 9th, 2019|Dinosaur and Prehistoric Animal News Stories, Geology, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Was There Life on Land During the Ediacaran?

The transition of vertebrates from fully aquatic to partially terrestrial animals has been well documented.  Transitional vertebrates such as the remarkable Tiktaalik roseae* provide evidence of the anatomical adaptations undertaken by back-boned animals as they conquered the land.  However, invertebrates got there first and before them the land was home to other organisms such as multi-cellular, photosynthesisng mats of algae.  When complex organisms, rather than members of the Plantae Kingdom or bacteria established themselves on land is somewhat controversial, but new clues might be emerging from fossils found in some of the oldest known soils on Earth.  Could land-dwelling organisms have been present during the Ediacaran?

An Ediacaran Fossil Affected by Wind-drift Deposition

Evidence of wind-drift deposition in ancient Ediacaran sediments.

A portion of a quilted Ediacaran fossil is partly covered by ancient wind deposition – source Namibia.

Picture Credit: Greg Retallack (Oregon University)

Not Marine Fossils But Fossils from a Fluvial Environment

Multi-cellular, terrestrial animals may have existed during the Ediacaran, that is the conclusion of Greg Retallack, fossil collections director at the University of Oregon’s Museum of Natural and Cultural History, writing in the journal Sedimentary Geology.  The evidence for such a conclusion emerged from fossil assemblages, previously considered to represent ocean organisms, found in thin layers of silt and sand located between thicker sandstone beds from Ediacaran-aged fossil localities of Nilpena, South Australia and in similarly aged rocks from Namibia.

The Ediacaran is the last geological period of the Precambrian (Neoproterozoic Era), it lasted from 635 million years ago to 542 million years ago and this period in Earth’s history was named after the Ediacara Hills, located north of Adelaide (South Australia), in which, geologist Reginald Sprigg discovered a remarkable collection of fossils representing bizarre, soft-bodied organisms.

Commenting on his new research Greg Retallack stated:

“These Ediacaran organisms are one of the enduring mysteris of the fossil record.  Were they worms, sea jellies, sea pens, amoebae, algae?  They are notoriously difficult to classify, but conventional wisdom has long held that they were marine organisms.”

Studying Interflag Sandstone Laminae

An in-depth, microscopic analysis of the sediments and their geochemical properties has led to a reassessment of the environmental conditions that led to their deposition.  The grains that make up the sediments, reveal telltale marks of ancient wind erosion, the sediments suggest wind-drift deposition between flood beds.  This indicates a terrestrial origin for them and not deposition in a marine environment, after all, wind (aeolian forces), hardly affect sand grains on the seabed.

These thin, silty to sandy layers that are “sandwiched” between thicker sandstone beds are referred to as interflag sandstone laminae, they are sometimes called “shims” or “microbial mat sandwiches”.  In the research paper, Greg Retallack found similar structures in modern river deposits as well as more ancient interflag sandstone laminae in Pennsylvanian (Upper Carboniferous), and Eocene fluvial levee facies.

Thin, Silty to Sandy Layers Deposited Between Thicker Layers of Sandstone

Interflag Sandstone Laminae

How interflag sandstone laminae form – wind deposition alternates with flood deposition – a phenomenon observed in modern fluvial environments.

Picture Credit: Greg Retallack (Oregon University)

Professor Retallack confirmed his diagnosis of an aeolian factor in the deposition by stating:

“Such wind-drifted layers are widespread on river levees and sandbars today.  They are present throughout the Flinders Ranges of South Australia and also in Ediacaran rocks of southern Namibia.”

If the sediments are affected by aeolian forces, then it follows that they were deposited in terrestrial environments and therefore the fossil assemblage associated with these deposits are very likely to represent a terrestrial biota.  The organisms that left these fossils would have been multicellular and quite complex, visible to the naked eye.  Such life would have preceded the emergence of the first land plants by many tens of millions of years.

Unearthing Important Clues

The Ediacaran biota remains extremely difficult to classify, only impressions have been preserved so the internal structure of most of these bizarre organisms is entirely unknown.  They could represent a “dead-end” in the evolution of complex life, or some of them might be ancestral to extant groups of animals.  The fauna of the Ediacaran might remain enigmatic, when it comes to learning what the fossils actually represent, but this new study offers some intriguing new evidence about the palaeoenvironment.

The Professor concluded:

“The investigation points to a terrestrial habitat for some of these organisms, and combined with growing evidence from studies of fossil soils and biological soil crust features, it suggests that they may have been land creatures such as lichens.”

*To read an article about Tiktaalik roseaeScientists Get to Grips with Tiktaalik’s Rear End

Life in the Ediacaran (Marine Biota)

Ediacaran marine life.

Life in the Ediacaran.  Up until now, most if not all of the life reconstructions have focused on a marine ecosystem scenario.

Picture Credit: John Sibbick

The scientific paper: “Interflag Sandstone Laminae, A Novel Sedimentary Structure, with Implications for Ediacaran Paleoenvironments” by Gregory J. Retallack published in Sedimentary Geology.

Everything Dinosaur acknowledges the help of a press release from the Univesity of Oregon in the compilation of this article.

4 01, 2019

New Middle Jurassic Pterosaur Described

By | January 4th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Klobiodon rochei – Fanged Flier of the Middle Jurassic

The famous Stonesfield Slate mines located in Oxfordshire have provided palaeontologists with a rich assemblage of Middle Jurassic (Bathonian), marine and terrestrial fossils, perhaps most famously, the Theropod Megalosaurus, the first dinosaur to be scientifically described.  Joining “big reptile” as a member of the area’s prehistoric biota is a newly described, toothy pterosaur – Klobiodon rochei.

Writing in the academic journal Acta Palaeontologica Polonica, Dr Michael O’Sullivan, (University of Portsmouth), has reviewed the extensive but highly fragmentary pterosaur material and uncovered evidence of well-armed and substantial flying reptiles from historically important, but overlooked, British fossils.

A Life Reconstruction of the Middle Jurassic Rhamphorhynchid Pterosaur Klobiodon rochei

Klobiodon rochei life reconstruction.

A life reconstruction of the Middle Jurassic pterosaur Klobiodon rochei.

Picture Credit: Mark Witton

An Unexpectedly Large and Formidable Flying Reptile

Working in collaboration with Professor David Martill (University of Portsmouth), Dr O’Sullivan examined many of the 215 fragmentary pterosaur fossils that have been collected from the Stonesfield Slate mines, K. rochei is one of the largest known from any Middle Jurassic-aged deposits.  It had an estimated wingspan of two metres, making it about the size of a modern-day mute swan.  Living around 166-165 million years ago, Klobiodon is an unexpectedly large and formidably-armed species.

Commenting on the significance of the newly described member of the Rhamphorhynchidae family, Dr O’Sullivan stated:

“It’s large fangs would have meshed together to form a toothy cage, from which little could escape once Klobiodon had gotten a hold of it.   The excellent marine reptiles and ammonites of the UK’s Jurassic heritage are widely known, but we celebrate our Jurassic flying reptiles far less.  The Stonesfield pterosaurs are rarely pretty or spectacular, but they capture a time in flying reptile evolution which is poorly represented globally.  They have an important role to play in not only understanding the UK’s natural history, but help us understand the bigger global picture as well.”

Honouring Comic Book Artist Nick Roche

The genus name translates as “cage tooth”, a reference to its huge, fang-like teeth, up to 26 millimetres long, that lined the jaw (this pterosaur has been named based on the morphology of the lower mandible).  The species name honours comic book artist Nick Roche in recognition of the role this popular media has in how extinct animals are portrayed.  Comic books are a medium where prehistoric animals are portrayed in an increasingly scientifically accurate manner, Roche’s work at the turn of this century was one of the earlier examples of a revival of palaeoart.

The Lower Jaw of Klobiodon rochei

Holotype fossil fo Klobiodon rochei.

The right lower mandible of the newly described Middle Jurassic pterosaur Klobiodon rochei.  The photograph shows the original label assigned to the fossil the validity of Rhamphocephalus depressirostris has now been questioned.

Only the lower jaw of Klobiodon is known, but it has a unique dental configuration that allows it to be distinguished from other pterosaurs.   It probably fed on small fish and squid, filling a role in the coastal ecosystem of an extant seagull or tern.

A Confused Picture

Much of Dr O’Sullivan’s research has involved untangling the messy science associated with these neglected specimens.  For example, the pterosaur specimens from the Great Oolite Group (Stonesfield Slate is a unit of the Great Oolite Group), are held in museums scattered across the world, although the majority are housed either at the London Natural History Museum or within the collection of the Natural History Museum of Oxford University.  Most of these fossils were assigned in the 19th Century to the genus Rhamphocephalus and to one of three species namely: Rhamphocephalus prestwichi, Rhamphocephalus bucklandi, and Rhamphocephalus depressirostris.

This study reviewed the British Middle Jurassic Pterosauria assemblage, evaluating both their systematics and taxonomic diversity.  The holotype of Rhamphocephalus, an isolated skull table, is found to be a misidentified crocodylomorph skull and the genus is therefore considered a nomen dubium.  The holotype of Rhamphocephalus bucklandi is identified as missing and that of Rhamphocephalus depressirostris has characters diagnostic at a family level, not a generic or specific one.  Both species are considered dubious.  Detailed examination of the entire pterosaur fossil assemblage shows that these fossils actually represent at least five different taxa, representing three families.  The researchers propose that the fossil material includes the earliest occurrences of the Monofenestrata clade and sub-order Pterodactyloidea, that was to give rise to some of the largest flying reptiles known to science.

Dr O’Sullivan explained:

“Klobiodon has been known to us for centuries, archived in a museum drawer and seen by dozens or hundreds of scientists, but it’s significance has been overlooked because it’s been confused with another species since the 1800s.”

A spokesperson from Everything Dinosaur stated:

“The pterosaur fossils associated with Middle Jurassic deposits of Oxfordshire and Gloucestershire have been neglected.  Research undertaken in the 19th century suggested that this was a time of relatively low pterosaur diversity.  This new research suggests that this was not the case, the Bathonian pterosaur assemblage is actually quite diverse with important early representatives of key types of flying reptile having been identified from this English fossil material.”

Stonefield Slate’s Most Famous Resident

Perhaps the most famous member of the Great Oolite Group biota is Megalosaurus bucklandii, the first dinosaur to be formally described.  The name was first used by James Parkinson in 1822 and published by the Reverend William Buckland in 1824, when he described various fossil remains including an iconic lower jaw bone (right dentary).  Size estimates vary for M. bucklandii, it could have been around ten metres in length.  It was probably the apex predator within this ecosystem and it is intriguing to think that the likes of Klobiodon could have scavenged the kills of Megalosaurus.

A Life Reconstruction of the Stonefield Slate’s Most Famous Member – Megalosaurus bucklandii

A life reconstruction of Megalosaurus bucklandii.

Megalosaurus feeding.  An illustration of the Middle Jurassic Ecosystem (Great Oolite Group).

Picture Credit: Mark Witton

The scientific paper: “Pterosauria of the Great Oolite Group (Bathonian, Middle Jurassic) of Oxfordshire and Gloucestershire, England” by Michael O’Sullivan and David M. Martill, published in published in Acta Palaeontologica Polonica (editor’s choice).

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

31 12, 2018

Scientists Discover the Earliest Evidence of Three Major Plant Groups

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

Permian Tropical Lowlands – A Hot Spot for Plant Evolution

Over recent days, team members at Everything Dinosaur have been reviewing the breadth and scope of the articles posted on this blog in the last twelve months.  The number of Sauropodomorpha themed articles (Sauropods and their ancestors), has been commented upon.  There have certainly been some amazing early, long-necked dinosaur discoveries, but we have also had a lot of exciting fossil discoveries concerning the Plantae Kingdom to write about too.  In 2019, we have reported on research that suggests the very first land plants evolved earlier than previously thought.  We have also written about new compelling evidence that suggests that flowering plants (Angiosperms), were present during the Middle Jurassic.

The Preserved Remains of a Seed Fern (Upper Permian Deposits – Jordan)

The fossilised remains of a seed fern.

A beautifully preserved seed fern frond in mudstone from the Jordan (Upper Permian).

Picture Credit: Palaeobotany Research Group, University of Münster/Blomenkemper et al

It seems fitting that our last post for 2019, once again looks at some remarkable plant fossil discoveries.

Scientists led by palaeobotanists from the University of Münster (western Germany), have uncovered a series of well-preserved fossils representing important plant groups from Upper Permian rocks at a site in Jordan.  The location, on the Dead Sea, has revealed the fossils of three major plant lineages:

  1. Podocarpaceae – a type of conifer, an evergreen tree
  2. Corystospermaceae – a type of seed fern (Pteridosperm)
  3. Bennettitales – cycad-like plants which produced seeds in cone-like structures

All the fossils pre-date the End-Permian extinction event that wiped out around 95% of all the life on our planet and the fossils prove that all three plant groups evolved millions of years earlier than previously thought.  For example, the now extinct Bennettitales were thought to have evolved sometime in the Triassic.  These fossils confirm that their evolution took place much earlier and that all three types of plant evolved before and persisted through the greatest mass extinction event known in Phanerozoic Eon.

A “Hidden Cradle of Plant Evolution”

Fossilised twigs representing the Podocarpaceae, commonly referred to as southern conifers, as the vast majority of extant species are found in the southern hemisphere, have been found.  These fossils represent the oldest record of any living conifer family.  In collaboration with colleagues from the Smithsonian Institute (USA) and scientists from the University of Jordan, the team also discovered the preserved, carbonised leaves and reproductive organs of Corystospermaceae, a group of seed ferns that went extinct some 150 million years ago, as well as remains of Bennettitales, a peculiar lineage of extinct seed plants with flower-like reproductive organs.

Trekking Through the Wadis on the Dead Sea Coast Looking for Plant Fossils

Exploring the Dead Sea coast of Jordan for Permian plant fossils.

Exploring Upper Permian fossil deposits for evidence of an ancient, lowland plant community.

Picture Credit: Palaeobotany Research Group, University of Münster/Blomenkemper et al

Evidence for the unexpectedly early occurrence of Corystospermaceae in the Permian of Jordan was first published about ten years ago by a research team led by Prof Dr Hans Kerp.  Since then, researchers have uncovered not only the well-preserved leaves but also the characteristic reproductive organs of this group of plants.  Like Bennettitales and Podocarpaceae, these plants were believed to have evolved millions of years later during the Early Mesozoic.

One of the co-authors of the scientific paper, published in the journal “Science”, Benjamin Bomfleur (Palaeobotany Research Group, University of Münster), stated:

“Analysis of characteristic epidermal cell patterns enabled us to resolve the systematic relationships of the plant fossils more precisely.  The study area is really exceptional, like a melting pot of floral provinces.”

An Unusual Mix of Plant Taxa

The researchers noted that the plant fossils at the site represent a diverse and very mixed assemblage of plant types.  The sedimentary deposits were laid down in an equatorial coastal environment with a distinct dry season – an ecosystem that rarely preserves delicate plant fossils.  The scientists conclude that, early evolutionary innovations can occur in drought-prone tropical habitats which rarely offer the conditions needed for fossil preservation.

Dr Bomfleur added:

“The occurrence of no less than three major ‘modern’ plant groups in deposits of just this single rock formation may indicate that such stressed and disturbance-prone tropical environments may have acted as evolutionary cradles also for other plant groups.”

Exquisite Details Revealed by Acid Etching

Once the fossil material had been collected by the field team, a variety of methods were employed in the preparation laboratory to help identify the plant types the fossils represented.  Powerful acids were used on some specimens to prepare plant cuticles for detailed microscopic analysis.  It can be very difficult to distinguish Pteridosperms from ferns based on foliage alone.  Similarly, the fossil leaves of cycads are very difficult to tell apart from those of true Bennettitales.  Identification is usually confirmed by examining microscopic details preserved in cells and on the cell wall of the cuticle, hence the need to use a variety of delicate techniques to reveal fine details.

Careful Exposure to Acids Helps Prepare Delicate Fossils for Microscopic Analysis

A seed fern frond is prepared for analysis.

A fragment of a seed fern frond after acid preparation.

Picture Credit: Palaeobotany Research Group, University of Münster/Blomenkemper et al

Survivors of a Mass Extinction Event

The plant fossils have been dated to approximately 255 million years ago (Lopingian Epoch of the Late Permian), so this ecosystem existed just a few million years prior to the “Great Permian Dying”, a mass extinction event that devasted both marine and terrestrial ecosystems.  The unexpected discovery of these three main groups of plants prior to this extinction event, not only pushes back the origins of these plant types in time, but also proves that all three groups survived the End-Permian extinction event.  Some of these lineages appear to span the mass extinction event, which suggests that the communities they supported may have been more stable than expected over this period of dramatic transition and change.  Thus, early evolutionary innovations can occur in drought-prone tropical habitats, which rarely offer the conditions needed for fossil preservation.  Seasonally dry tropical environments could be described as “cradles of evolution”.

The scientific paper: “A Hidden Cradle of Plant Evolution in Permian Tropical Lowlands” by Patrick Blomenkemper, Hans Kerp, Abdalla Abu Hamad, William A. DiMichele and Benjamin Bomfleur published in the journal Science.

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

To read Everything Dinosaur’s blog post on the idea that the first land plants evolved millions of years earlier than once thought: Plants May Have Originated 100 Million Years Earlier

To read Everything Dinosaur’s article about the discovery of fossils representing very early flowering plants: The First Flowering Plants Originated in the Early Jurassic

30 12, 2018

Palaeontology Predictions for 2019

By | December 30th, 2018|Dinosaur Fans, Main Page, Palaeontological articles, Press Releases|0 Comments

Palaeontology Predictions for 2019

Time to stick our collective necks out to see if we can predict the sort of news stories that we are going to feature on this blog next year (2019).  We took a break from making predictions in 2018, after all, just like fossil collecting, attempting to foresee some of the scientific discoveries that will be covered in the next twelve months can be a bit of a hit and miss affair to say the least.  However, with our trusty geological hammers tucked into our rucksack next to our crystal ball, here are our suggestions as to the fossil finds and palaeontology themed stories that 2019 will bring.

1).  Bring on the Horned Dinosaurs – More Ceratopsians to be Named and Described from America

After the dearth of new horned dinosaurs named and described this year (only one – Crittenceratops krzyzanowskii), we expect the Marginocephalia clade, specifically the North American Ceratopsia to be increased substantially again next year.  Team members at Everything Dinosaur predict that at least four new horned dinosaurs from the United States will be named and described in 2019.

The Diverse Ceratopsia – Likely to be More Diverse by the end of 2019

Divesity in the Ceratopsia.

Diversity in the horned dinosaurs.  Everything Dinosaur team members predict that there will be another four new Ceratopsia taxa from the United States described in 2019.

Picture Credit: Everything Dinosaur

2).  Herefordshire Lagerstätte To Make Its Mark Again

In recent years, we have featured a number of amazing fossil finds from the Silurian-aged deposits from the secret Lagerstätte in the county of Herefordshire.  These fossils represent an ancient marine biota that was covered in fine volcanic ash some 425 million years ago.  Such is the exquisite nature of their taphonomy that even the finest soft tissues have been preserved.  We predict that British-based scientists will utilise high-resolution computed tomography in conjunction with computer-generated three-dimensional modelling to reveal a new species of Silurian marine invertebrate.

3).  A New Dinosaur from India

More Chinese dinosaur fossil discoveries are going to be made in 2019.  We also expect fresh insights into the Cretaceous flora and fauna entombed in amber from Myanmar.  However, amongst the twenty or so new species of dinosaur described in the next twelve months, we predict that one of these new-to-science specimens will be found in India.  Many parts of the world (Africa and Asia) for example, are being opened up to geological and fossil exploration.  Several different types of dinosaur are already known from the sub-continent and we predict that there will be a new addition to the dinosaur fauna described from India.

Will a New Dinosaur Species be Discovered in India?

Will a new dinosaur taxon be discovered in Indian in 2019?

Will a new dinosaur species be discovered in India?

Picture Credit: Everything Dinosaur

4).  Everything Dinosaur – A New Look to the Website

As well as writing about what other people have been doing, we expect our blog site to update readers on how Everything Dinosaur itself is evolving and changing.  Our core values of customer service and finding the very best quality prehistoric animal products are not going to change, but visitors to: Everything Dinosaur can expect to see some changes next year – all aimed at improving our service and helping our customers.  The number of different types of prehistoric animal models that we offer is also going to increase, but by how many?  Let’s predict another fifty new models  to be made available on our website in 2019.

5).  More Fossils Reveal Melanosomes

With more and more sophisticated and sensitive devices being made available to palaeontologists to aid their research, 2019 will see further developments in the study of fossil specimens on the molecular level.  There have already been some remarkable papers published on the presence of fossilised microscopic structures containing the colour pigment melanin (melanosomes) and we confidently predict that this trend will continue.  We predict that further evidence will emerge next year concerning the colour of members of the Dinosauria.

The Hunt is on for More Melanosome Structures in Fossil Material

Identifying potential melanosomes in fossil material.

Sausage-shapes – potential melanosomes.  Research is likely to continue into prehistoric animal colouration in 2019.

Picture Credit: Lund University (Johan Lindgren)

6). Giant Azhdarchid Pterosaurs

Recent fossil discoveries have indicated that the Pterosauria were more diverse than previously thought towards the very end of the Cretaceous (Campanian to Maastrichtian faunal stages).  Everything Dinosaur has reported on the discovery of several fossil fragments from Europe and Africa in recent years and we predict that a new species of large, very probably azhdarchid, pterosaur will be described in 2019.  The fossil find could come from northern Africa or perhaps from the famous Hateg Basin deposits of Romania.

An Azhdarchid Pterosaur Wrist Bone (Hateg Island) – Will a New Species of Azhdarchid Pterosaur be Described in 2019?

Azhdarchid Pterosaur wrist bone (Hateg Formation).

Azhdarchid pterosaur wrist bone.  What surprises lie in wait for flying reptile researchers in 2019?

Picture Credit: Mátyás Vremir

7).  New Tyrannosaurids from the United States

We began our predictions by stating that we thought it was likely that at least four new horned dinosaur taxa from the USA will be named next year.  With all these herbivores being named and described, it would not surprise us if some more, large Theropod dinosaurs were formally described from fossil material found in the United States next year as well.  Let us conclude our crystal ball gazing by suggesting that two new species of Late Cretaceous tyrannosaurid will be identified from fossil finds from the southern USA (southern parts of Laramidia).

Will New Members be Added to the Tyrannosauridae Family in 2019?

Will there be new types of tyrannosaurid described in 2019.

Will new Tyrannosauridae taxa be described in 2019?

Picture Credit: Everything Dinosaur

This time next year, as we approach the end of 2019, we will review our predictions and see how we got on.

27 12, 2018

Convoluted Nasal Passages Helped Armoured Dinosaurs Cool Their Brains

By | December 27th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

Armoured Dinosaurs Coped with the Mesozoic Heat Thanks to Nasal Air-conditioning

Being a very large dinosaur covered in armour, might help you to keep safe from attack by predatory dinosaurs, but this body plan does have its downsides.  For example, how do you keep cool when you have a very broad body?  New research from scientists based at Ohio University and the New York Institute of Technology College of Osteopathic Medicine at Arkansas State, suggests that those complicated Ankylosauria nasal passages acted like heat-exchanges helping to prevent these dinosaurs from overheating.  In essence, this study published in the academic, on-line journal PLOS One, suggests that members of the Ankylosauria clade had built-in air conditioning units in their noses.

Convoluted Nasal Passages Helped Armoured Dinosaurs to Avoid Overheating

Nasal air-conditioning in armoured dinosaurs.

Ankylosauria nasal passages used as heat exchanges.

Picture Credit: PLOS One with additional annotation from Everything Dinosaur

Panoplosaurus and Euoplocephalus Studied

The researchers, which included Jason Bourke (Assistant Professor at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State), chose to examine the craniums of Euoplocephalus (E. tutus), a member of the Ankylosauridae family of dinosaurs along with the nodosaurid Panoplosaurus mirus.  A representative of the Nodosauridae family as well as a member of the Ankylosauridae was selected as Nodosaurs tend to have much narrower muzzles than the related Ankylosaurs.  In this way, the scientists were able to compare and contrast the different nasal passages associated with these two types of armoured dinosaur.

Assistant Professor Bourke commented:

“The huge bodies that we see in most dinosaurs must have gotten really hot in warm Mesozoic climates.  Brains don’t like that, so we wanted to see if there were ways to protect the brain from cooking.  It turns out the nose may be the key.”

Dr Victoria Arbour, an Authority on the Ankylosauria Poses Next to the Broad Skull of Euoplocephalus (E. tutus)

Dr Victoria Arbout next to a Euoplocephalus skull.

Victoria next to a skull of a Euoplocephalus tutus (University of Alberta).  Note the broad muzzle and the wide skull of this Late Cretaceous ankylosaurid.

Picture Credit: Angelica Torices

Computational Fluid Dynamic Analysis

The research team created three-dimensional, computer generated models of two famous skull fossils, a Panoplosaurus specimen housed in the Royal Ontario Museum collection and a Euoplocephalus skull from the American Museum of Natural History (New York).  A computational fluid dynamic analysis was then undertaken to map how air would have moved through the nasal passages as these dinosaurs breathed.  The scientists wanted to test the heat exchange capacity of the complex passages, to see how well the Ankylosauria noses transferred heat from the body to the inhaled air.

Co-author of the study, Lawrence Witmer (Ohio University), explained:

“A decade ago, my colleague Ryan Ridgely and I published the discovery that ankylosaurs had insanely long nasal passages coiled up in their snouts.  These convoluted airways looked like a kid’s ‘crazy-straw!’  It was completely unexpected and cried out for explanation.  I was thrilled when Jason took up the problem as part of his doctoral research in our lab.”

It is thought that these complex nasal passages gave members of the Ankylosauria clade, an exceptional sense of smell.  This may have been their primary function, however, noses are also heat exchangers, ensuring that air is warmed and humidified before it reaches the delicate lungs.  To accomplish this effective air conditioning, birds and mammals, including humans, rely on thin curls of bone and cartilage within their nasal cavities called turbinates, which increase the surface area, allowing for air to come into contact with more of the nasal walls.   Ankylosaurs and nodosaurids lacked turbinates, to compensate for this they evolved exceptionally long and twisty nasal passages.

Comparing Armoured Dinosaurs to Living Animals

When the researchers compared their findings to data from living animals, such as the nasal passages of an avian dinosaur (pigeon),  they discovered that the noses of armoured dinosaurs were just as efficient at warming and cooling respired air.  The length of the winding and twisting nasal passages in the two armoured dinosaurs studied were also measured.  In the narrow-snouted, nodosaurid Panoplosaurus, the nasal passages were a bit longer than the skull itself and in Euoplocephalus they were almost twice as long as the skull, which is why they are coiled up in the snout.

To see if nasal passage length was the reason for this efficiency in heat exchange, the researchers created alternative models with shorter, simpler nasal passages that ran directly from the nostril to the throat, as in most other animals.  The results clearly showed that nose length and the length of the nasal passages were indeed key to their air-conditioning ability.

Assistant Professor Bourke stated:

“When we stuck a short, simple nose in their snouts, heat-transfer rates dropped over fifty percent in both dinosaurs.  They were less efficient and didn’t work very well.”

Helping to Cool Brains

The blood vessels in the skull leading up to and surrounding the brain were mapped.  The scientists wanted to explore whether the internal plumbing of the snout helped to cool the brains of armoured dinosaurs.  The team found a rich blood supply running adjacent to the convoluted nasal passages.

Co-author Ruger Porter (Ohio University), explained:

“When we reconstructed the blood vessels, based on bony grooves and canals, we found a rich blood supply running right next to these convoluted nasal passages.  Hot blood from the body core would travel through these blood vessels and transfer their heat to the incoming air.  Simultaneously, evaporation of moisture in the long nasal passages cooled the venous blood destined for the brain.”

Euoplocephalus Kept a Cool Head

Cooling the brain of Euoplocephalus

Vascular pathways associated with the brain of Euoplocephalus tutus.  Red highlighted veins indicate main channels of heat transfer.

Picture Credit: PLOS One

Thermoregulation – A Problem for Large Animals

The large, broad bodies of Panoplosaurus and Euoplocephalus were really good at retaining heat, which might have some advantages, especially when you need to stay warm, but this does cause problems when large Tetrapods need to keep their cool.  This heat-shedding problem would have put them at risk of overheating even on cloudy days.  In the absence of some protective mechanism, the delicate neural tissue of the brain could be damaged by the hot blood from the body core.  In simple terms, the small brains of armoured dinosaurs might have been cooked inside the skull.

The complicated nasal airways of these dinosaurs were acting as radiators to cool down the brain with a constant flow of cooled venous blood.  This natural engineering feat also may have allowed some members of the Dinosauria to evolve into huge animals.

Lawrence Witmer added:

“When we look at the nasal cavity and airway in dinosaurs, we find that the most elaborate noses are found in the large dinosaur species, which suggests that the physiological stresses of large body size may have spurred some of these anatomical novelties to help regulate brain temperatures.”

26 12, 2018

“Little Foot” Reveals Her Secrets

By | December 26th, 2018|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Fourteen Years of Work to Tell the Story of “Little Foot”

Christmas is a time for family get togethers and spending time with relatives.  Today, we feature the astonishing story of the remarkable and nearly complete fossilised skeleton of an Australopithecine nicknamed “little foot” a member of the Hominidae family and as such, a long, distant relative of us all.  The Sterkfontein Caves in South Africa are located around twenty-five miles north-west of Johannesburg in Gauteng Province (South Africa).  Numerous fossils of hominids are known from the Caves and the surrounding area, which is called the Cradle of Humankind and Everything Dinosaur has reported on several recent and highly significant Australopithecine fossil finds, however, at an estimated 3.67 million years of age, “little foot” is the oldest Australopithecine specimen ever found in southern Africa.

The Partially Uncovered Remains of the Australopithecine Nicknamed “Little Foot”

In situ fossils of the Australopithecine "little foot" in the Sterkfontein Caves.

The fossilised remains of the Australopithecus nicknamed “little foot” found in the Sterkfontein Caves.  The skull can be seen in the bottom right corner of the photograph.

Picture Credit: PAST/Paul Myburgh

Lead researcher Professor Ron Clarke and his team have published the first, formal scientific description of the fossil material in the “Journal of Human Evolution”.  Such is the completeness of the skeleton, that anthropalaeontologists confidently predict that many more papers will be written, as this is the only known, virtually complete fossil skeleton of an Australopithecus discovered to date.  It has taken fourteen years of painstaking work to excavate the fossils and six years to clean and prepare them for detailed study.

Dedicated Research Leads to Scientific Breakthrough

In 1994 and 1997, Professor Clarke identified twelve foot and lower leg bones of one Australopithecus individual misidentified as animal fossils in boxes stored at Sterkfontein and at the University of Witwatersrand (Johannesburg).  Clarke and his assistants, Nkwane Molefe and Stephen Motsumi, then looked for and located the very spot where the bones had been blasted out by lime miners, probably sometime in the 1920’s deep inside the Sterkfontein Caves.  It was a real case of detective work, as Nkwane and Stephen worked in the caves to try to identify the very spot where the fossils that had been stored in the boxes, actually came from.  After one and a half of days of carefully searching the caves, they found that the pieces matched with two broken-through shin bones in a concrete-like cave infill and started the excavation process, first with hammer and chisel to remove the overburden, before turning to the painstaking process of locating and exposing the bones with an airscribe.

The Researchers were Able to Locate the Rest of the Skeleton by Matching Pieces Together

Identifying the rest of the "little foot" skeleton.

Researchers demonstrate how the rest of the skeleton was found by matching fragments of limb and ankle bones to fossil material exposed in the cave.

Picture Credit: PAST/Paul Myburgh

Unusual Taphonomy of the Female Australopithecine

The taphonomy of “little foot” is unusual.  The female (identified by the shape of the pelvis), fell into a cave and the body became mummified in the exceptionally dry conditions.  The absence of predators allowed the body to remain undisturbed but at some time in the past there was a slight displacement of some skeletal parts through slippage on the rock-strewn talus slope in the cave, crushing and breaking of some bones through rockfall and pressure, calcification after a change to wet conditions, and then slight downward collapse of part of the cave infill.  This partial collapse left voids that were later filled with stalagmitic flowstone that encased breaks through the femurs.  When the first attempts to date the fossils was made, an analysis of the stalagmite flowstone encasing the fossil was made.  However, the flowstones were later infills in voids created by the collapse that had broken and displaced parts of the skeleton.  The data gave a more recent date for the fossil, “little foot” was actually much older, having lived during the Zanclean stage of the Pliocene Epoch.

Professor Ron Clarke Demonstrates the Use of an Airscribe

Professor Ron Clarke demonstrates the use of an airscribe.

Professor Ron Clarke showing how an airscribe was used to remove the surrounding matrix.

Picture Credit: PAST/Paul Myburgh

Commenting on the earlier attempts to date the skeleton, Professor Clarke stated:

“The flowstones do not date the skeleton.  In 2015, cosmogenic isochron dates using 26Al and 10Be were published in Nature, showing that the age of the actual breccia containing the skeleton dates back ca 3.67 million years.  This is consistent with the original age estimates of around 3.5 million years that were proposed based on the low stratigraphic position of the deposit within the cave.”

Helping to Reassess the Australopithecus Genus

Study of the anatomical features of “little foot” suggests that the skeleton is most similar to the Australopithecine known as A. prometheus, which was proposed as a species in 1948 by the famous anthropologist Raymond Dart.  The phylogeny of the Australopithecines and related genera is controversial.  It is hoped that the virtually complete skeleton, so painstakingly excavated, will shed new light on taxonomic relationships, helping to fill in a number of evolutionary gaps.

Professor Ron Clarke and the Skull of “Little Foot”

The skull of "little foot" with Professor Ron Clarke

Professor Ron Clarke with the skull and left humerus of “little foot”.

Picture Credit: PAST/Paul Myburgh

Everything Dinosaur acknowledges the assistance of a press release from the University of Witwatersrand and supporting materials in the compilation of this article.

19 12, 2018

Dozens of Dinosaur Footprints Exposed at Hastings

By | December 19th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Geology, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Dinosaur Footprints Exposed by Cliff Erosion

The seaside town of Hastings in East Sussex is steeped in history.  It is synonymous with the battle that began the Norman conquest back in 1066 but scientists have been aware for many years that the cliffs to the east of the town contain evidence of much older inhabitants – dinosaurs.  Researchers from the Department of Earth Sciences at Cambridge University have published a paper this week documenting dozens of Early Cretaceous dinosaur tracks and footprints that represent at least seven different kinds of dinosaur.

Two Iguanodontian Prints from the Lee Ness Sandstone (Ashdown Formation) Exposed at Hastings

Two iguanodontian footprints from the Lee Ness Sandstone.

Examples of two iguanodontian footprints from the Lee Ness Sandstone (Ashdown Formation).

Picture Credit: Neil Davies/University of Cambridge

A Rich and Diverse Dinosaur Fauna

The footprints and trackways were identified and mapped by a team of researchers from Cambridge University between 2014 and 2018, following periods of extensive coastal erosion along the cliffs to the east of Hastings.  The footprints range in size from 2 cm wide to over 60 cm across.   These prints and tracks record a rich and diverse dinosaur fauna from the Lower Cretaceous – Lee Ness Sandstones (Ashdown Formation), which date from approximately 140 million years ago (Berriasian faunal stage of the Cretaceous).

The exact age of the Lee Ness Sandstone strata is unknown, however, the Ashdown Formation is estimated to be around 145-133 million years old, based on relative dating of ostracod fossils.

The researchers, writing in the academic journal ” Palaeogeography, Palaeoclimatology, Palaeoecology”, report on more than 85 exceptionally well-preserved dinosaur footprints, comprising prints from at least seven different types of dinosaur (ichnogenera).  They document the trace fossils eroding out of cliffs and their work records the greatest diversity of dinosaurs in a single location in Cretaceous-aged rocks found in the UK.  In particular, a variety of armoured dinosaurs (Thyreophora) are represented.

One of the Many Different Types of Armoured Dinosaur Print Found

Armoured dinosaur footprint - Ashdown Formation (Hastings).

A footprint ascribed to an armoured dinosaur (Thyreophora) from the Lee Ness Sandstone (Ashdown Formation).  The print has been assigned to the Tetrapodosaurus ichnogenus.

Picture Credit: Neil Davies/University of Cambridge

Details of Skin, Scales and Claws are Visible

The trace fossils are preserved in remarkable detail.  Impressions of skin, scales and even toe claw impressions have been preserved.

A Close View of an Iguanodontian Print Showing a Distinct Claw Impression

Preserved iguanodontian claw impression.

A close view of an iguanodontian claw impression preserved within one of the dinosaur footprints.

Picture Credit: Neil Davies/University of Cambridge

An Iguanodontian Footprint with Preserved Skin Impressions

Iguanodontian footprint showing skin impressions.

Some of the tracks from recent rock falls show skin impressions.  This is the skin impression from the underside of an iguanodontian footprint.

Picture Credit: Neil Davies/University of Cambridge

The best preserved prints come from large blocks of stone that are mapped and photographed after recently falling from the cliff.  The tracks are quickly eroded with prolonged exposure to the elements and from damage caused by further rock falls.  When dealing with a rapidly eroding cliff, it is essential that any fresh rock falls are examined and any fossils contained within the blocks are mapped and measured.

Two Photographs (February 2017 and February 2016) Showing the Extent of the Trace Fossil Erosion

Weathering of the dinosaur tracks at Hastings.

The effect of weathering on the trace fossils.  Over 12 months the tracks are heavily eroded.

Picture Credit: Neil Davies/University of Cambridge

Wealden Group Trace Fossils

The Ashdown Formation is part of the Wealden Group of rock formations, the most important sequence of dinosaur fossil bearing strata in England.  Numerous fossilised footprints are associated with the Wealden Group and the first report of tracks was made in 1846 by the Reverend Tagart, who described a series of three-toed prints, which he thought had been made by giant birds.  Never before has such a diverse footprint assemblage been mapped and documented in the British Isles.

A Table Showing the Different Types of Dinosaur Footprint (Morphotypes) Mapped at the Location

Lee Ness Sandstone dinosaur footprint analysis.

A table showing the number and characteristics of the Hastings dinosaur footprint fossils.

Table Credit: Palaeogeography, Palaeoclimatology, Palaeoecology with additional notation from Everything Dinosaur

One of the authors of the scientific paper, Anthony Shillito, a PhD student in Cambridge’s Department of Earth Sciences commented:

“Whole body fossils of dinosaurs are incredibly rare.  Usually you only get small pieces, which don’t tell you a lot about how that dinosaur may have lived.  A collection of footprints like this helps you fill in some of the gaps and infer things about which dinosaurs were living in the same place at the same time.”

Different Kinds of Theropod Dinosaurs

The footprints along with the various plant fossils and invertebrate trace fossils (burrows), are helping the scientists to put together a picture of life in this part of the world in the Early Cretaceous.  Dinosaurs dominated the biota, with several different types of meat-eating dinosaur (Theropods) identified, including a potential dromaeosaurid-like dinosaur, as two-toed prints (didactyl) have been found.

Different Types of Theropod Track Have Been Found

Different types of Theropod footprint. Scale bars = 5 cm.

Examples of different types of Theropod footprint (Lee Ness Sandstone – Ashdown Formation).

Picture Credit: Neil Davies/University of Cambridge

The picture above shows four different types of Theropod footprint identified at the Hastings site.  Picture (A) shows a large tridactyl (three-toed) cast with a long digit III and a faint heel impression.  The footprint in (B), is also large but the toes are narrower and elongated, maintaining a consistent width for their whole length.  The cast has no heel pad impression.  The Theropod morphotype (C), represents a much smaller animal with digit III being much longer than digits II and IV.  Intriguingly, the researchers have also logged potential two-toed prints (D), this suggests that this floodplain, braided environment might have been home to dromaeosaurid-like dinosaurs.

PhD student Shillito added,

“You can get some idea about which dinosaurs made them from the shape of the footprints, comparing them with what we know about dinosaur feet from other fossils lets you identify the important similarities.  When you also look at footprints from other locations you can start to piece together which species were the key players.”

Although, the majority of the footprints have been ascribed to Ornithopods, and several are referred to as iguanodontian, none of these prints were made by a member of the Iguanodon genus.  Iguanodon (I. bernissartensis), lived many millions of years after these prints were formed.  There have been many different types of iguanodont described, it is possible that the larger prints were made by an animal such as Barilium dawsoni.  The slightly smaller prints could have been created by the iguanodontid Hypselospinus (H. fittoni).

The Three-toed Tracks of a Small Ornithopod Dinosaur

Small Ornithopod trackway (Ashdown Formation).

Trackway assigned to a small, Ornithopod dinosaur.

Picture Credit: Neil Davies/University of Cambridge

Dinosaurs Helping to Shape the Environment

Anthony Shillito is focusing on the role played by dinosaurs in terms of shaping their environment, how dinosaurs behave as zoogeomorphic agents.  Large animals today, such as elephants and hippos can alter their habitats as they interact with their environment.  Hippos for example, can create river channels and divert the course of water flow.  Dinosaurs very probably did the same, with larger dinosaurs having a bigger impact than smaller dinosaurs.

The student commented:

“Given the sheer size of many dinosaurs, it’s highly likely that they affected rivers in a similar way, but it’s difficult to find a ‘smoking gun’, since most footprints would have just washed away.  However, we do see some smaller-scale evidence of their impact; in some of the deeper footprints you can see thickets of plants that were growing.  We also found evidence of footprints along the banks of river channels, so it’s possible that dinosaurs played a role in creating those channels.”

Evidence of Sauropods?

Footprint evidence indicating the largest dinosaurs of all, the presence of Sauropods is virtually absent from the site.  Three poorly preserved trace fossils have been tentatively ascribed to the Sauropoda, although they are very indistinct and could represent under traces representing the tracks of other ichnogenera.

It is very likely that there are many more dinosaur footprints hidden within the eroding sandstone cliffs of East Sussex, but the construction of sea defences in the area to slow or prevent the process of coastal erosion may mean that they remain locked away within the rocks.

The scientific paper: “Dinosaur-landscape Interactions at a Diverse Early Cretaceous Tracksite (Lee Ness Sandstone, Ashdown Formation, southern England)” by Anthony P. Shillito and Neil S. Davies published in Palaeogeography, Palaeoclimatology, Palaeoecology.

14 11, 2018

Fossil Bird from Late Cretaceous Utah – Deepens a Mystery

By | November 14th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Mirarce eatoni – Deepens the Mystery Over Late Cretaceous Avian Extinctions

All living birds from Albatrosses to Zebra finches belong to one group of avians – the Neornithes.  Our feathered friends share a number of key anatomical traits that defines them as a group from the smallest such as the Bee Hummingbird to the largest living bird, the Ostrich.  However, back in the Cretaceous, things were very different.  There were several different taxa of birds including the very diverse and highly successful Enantiornithines that shared the skies with early members of the Neornithines, but only the ancestors of today’s extant birds survived the end-Cretaceous extinction event and that’s a puzzle for palaeontologists.

The puzzle has just become a little more complex with the publication of a scientific paper in the on-line, open access journal “PeerJ”.  This paper describes the fossilised remains of an Enantiornithine that lived around 75 million years ago, in Utah (USA).  This prehistoric bird, about the size of a Raven, has been named Mirarce eatoni and its fossils show that it was probably a match for most modern birds in terms of its aerial abilities.

Perched on the Horns of a Utahceratops (Mirarce eatoni)

Mirarce eatoni - life reconstruction.

An illustration of the Late Cretaceous enantiornithine Mirarce eatoni.

Picture Credit: Brian Engh

This leads to one very intriguing question, if Enantiornithines like Mirarce were so advanced, then why after the Cretaceous-Palaeogene mass extinction event did only one group of birds survive?

A Complete Anatomical Description

The fossil material consists of several neck bones (cervical vertebrae), back bones (dorsal vertebrae), the fused caudal vertebrae making up the pygostyle, elements from the limbs, parts of the hips, a partial scapula, coracoid, the furcula (wishbone) and several other fragmentary elements including the radius and ulna.  This represents a veritable treasure trove of North American Enantiornithine fossils for palaeontologists to study, most North American members of this taxon are known from very scrappy fossil remains, mostly consisting of isolated fused leg bones and toes.  All in all, about 30% of the total skeleton is known and crucially, unlike most of the more complete Enantiornithine specimens from the Lower Cretaceous deposits of China, this specimen, is preserved in three-dimensions, it has not been crushed as flat as a pancake.  The excellent state of preservation and the number of fossil bones has permitted the researchers to undertake a complete anatomical description.

A Skeletal Reconstruction of the Newly Described North American Enantiornithine Mirarce eatoni

Mirarce eatoni skeletal reconstruction.

A skeletal reconstruction of the Enantiornithine Mirarce eatoni from Late Cretaceous Utah.  The bones shaded white represent known fossil material.  Note, cranial material is not known.

Picture Credit: Scott Hartman

The “Kaiparowits Avisaurid”

The specimen was originally discovered back in 1992, by University of California, Berkeley palaeontologist Howard Hutchinson, whilst he was exploring Kaiparowits Formation deposits for evidence of turtles.  It was quickly identified as an Enantiornithine and ascribed to the Avisauridae family, a family of prehistoric birds known from South America, North America, parts of Europe, Siberia and the Middle East (Lebanon).  The partial skeleton (UCMP 139500), was nicknamed the “Kaiparowits avisaurid”.   Although, its significance was noted, after all, the fossils represent the most complete example of an Enantiornithine ever found in North America, it remained undescribed.  All that changed when PhD student Jessie Atterholt (University of California, Berkeley), was given the opportunity to provide a formal scientific description.

Research Suggests that Mirarce eatoni was a Strong Flier and Well-Adapted to Life in the Late Cretaceous

Mirarce eatoni - life reconstruction.

A close-up view of the newly described Late Cretaceous bird Mirarce eatoni (colouration and plumage speculative).

Picture Credit: Brian Engh

A Strong and Capable Flier

In collaboration with her colleague Howard Hutchinson and with the support of Jingmai O’Connor, from the Chinese Academy of Sciences and an authority on Cretaceous fossil birds, a complete analysis of the fossil bones was undertaken.  This study revealed that M. eatoni possessed several of the same physical adaptations for highly refined powered flight that modern birds (Neornithines) have.

Fossils of Enantiornithines from the Lower Cretaceous of China, birds such as Confuciusornis sanctus show a mix of basal and more advanced anatomical traits.  For example, the breast bone (sternum), of C. sanctus, is relatively small.  Modern birds have a deeply keeled sternum, this allows the attachment of large muscles to aid powered flight.  The wishbone (furcula) of Confuciusornis and most other Early Cretaceous Enantiornithines, is little more than a curved bar.  However, the furcula of M. eatoni is shaped much more like the “V-shaped” wishbones of modern birds.  The furcula of Mirarce would have been able to flex and to store energy released during the flapping of the wings.

Commenting on the significance of these anatomical characteristics, Atterholt stated:

“We know that birds in the early Cretaceous, about 115 to 130 million years ago, were capable of flight but probably not as well adapted for it as modern birds.  What this new fossil shows is that Enantiornithines, though totally separate from modern birds, evolved some of the same adaptations for highly refined, advanced flight styles.”

The Furcula (Wishbone) of Mirarce eatoni

The furcula of Mirarce eatoni.

Two views of the wishbone (furcula) of Mirarce eatoni (A) dorsal and (B) ventral with line drawings.  Scale bar = 1 cm.

Picture Credit: PeerJ

Quill Knobs?

A close examination of the right ulna (lower arm bone), revealed evidence of two roughened patches preserved on the shaft of the bone.  These rough patches were interpreted as being attachment sites for quill knobs, that anchor the wing feathers to the skeleton and to help strengthen the wings for use in active, prolonged, powered flight.  Quill knobs are found in living birds.  This is the first time that such a feature has been seen in an Enantiornithine and indicates that Mirarce was, very probably, a strong flier.

Potential Quill Knobs Identified in an Enantiornithine (M. eatoni)

Quill knobs on an Enantiornithine.

Roughed structures on the ulna of Mirarce compared to the quill knobs found on the ulna of a Pelican.

Picture Credit: PeerJ

If these structures are quill knobs, then this suggests that this anatomical trait evolved in parallel with members of the Dinosauria (dromaeosaurids and other maniraptorans along with the ornithomimids) and in parallel with a number of types of prehistoric bird.

How Did Mirarce Get Its Name?

The genus name reflects that fantastic state of preservation of the fossil material (Latin “mirus” for wonderful) and after Arce, the winged messenger of the Titans in Greek mythology.  The trivial name honours Dr Jeffrey Eaton, in recognition of his work studying the vertebrates of the Kaiparowits Formation.  A spokesperson from Everything Dinosaur commented that this prehistoric bird’s name was pronounced “mere-ark-ee ee-tow-eye”.

But Why Did These Advanced Enantiornithines Die Out?

If Late Cretaceous Enantiornithines were just as advanced as modern birds, then, why did they die out with the non-avian dinosaurs while the ancestors of modern birds survived the extinction event?

Atterholt, who has moved onto a position of Assistant Professor and human anatomy instructor at the Western University of Health Sciences in Pomona (California), added:

“This particular bird is about 75 million years old, about 10 million years before the die-off.  One of the really interesting and mysterious things about Enantiornithines is that we find them throughout the Cretaceous, for roughly 100 million years of existence and they were very successful.  We find their fossils on every continent, all over the world, and their fossils are very, very common, in a lot of areas more common than the group that led to modern birds.  Yet modern birds survived the extinction while Enantiornithines go extinct.”

Forest Dwellers Versus Seed Eaters

A number of ideas have been put forward to help explain why some types of birds survived the end-Cretaceous mass extinction event whilst others did not.  For example, one hypothesis proposes that Enantiornithines were forest dwellers and when the asteroid strike/volcanism resulted in a dramatic loss of woodland habitats, these types of birds suffered more than other birds that lived in different environments.

The absence of cranial material prevents the researchers from investigating what Mirarce might have eaten.  Most known members of the Enantiornithes had teeth in their beaks and Mirarce supports the idea that these types of birds gradually got larger over time, but what this bird ate remains a mystery.  If it had been a predator of small vertebrates and insects, any major disruption to the food chain could have led to extinction.  However, a paper published in 2016 proposed that birds with toothless beaks such as the early Neornithines could have survived the extinction event by eating seeds that persisted in the soil.

To read more about this paper: Seed Eating May Have Helped the Birds Survive

The scientific paper: “The Most Complete Enantiornithine from North America and a Phylogenetic Analysis of the Avisauridae” by Jessie Atterholt, J. Howard Hutchinson and Jingmai K. O’Connor published in PeerJ.

13 11, 2018

Getting to the Bottom of Ornithischian Teeth

By | November 13th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

Scientists Sink Their Teeth into Toothy Dinosaur Problem

Two of the most successful lineages of Ornithischian dinosaurs are the Ceratopsians (horned dinosaurs) and the Hadrosaurs (duck-billed dinosaurs).  These herbivores dominated the megafauna of many Late Cretaceous environments and one of the reasons for their success was their remarkable dental batteries.  Although horned dinosaurs and duck-bills processed plant food in their mouths differently, (they had different chewing and grinding actions), the rows of teeth permitted these types of plant-eaters to process the toughest vegetation extremely efficiently

The Dental Battery of a Typical Hadrosaurid

Typical Hadrosaur dental battery.

These teeth were made for grinding. The rows and rows of tough teeth in the jaw of a hadrosaurid – the dental battery.

Picture Credit: Dr Gregory Erickson

However, the evolution of these dental batteries is poorly understood, so a team of Canadian and Chinese scientists set out to examine how this dentition may have come about.  To do this they examined the teeth morphology and jaws of a little Ornithopod from north-eastern China called Changchunsaurus parvus.  This light-weight dinosaur that measured around 1.5 metres in length, is known from several skulls and other postcranial material from Jilin Province (China).

A Life Reconstruction of the Ornithopod Changchunsaurus (C. parvus)

Changchunsaurus Life Reconstruction

An illustration of the Chinese Ornithopod Changchunsaurus. Note scale bar = 1 metre.

Picture Credit: Everything Dinosaur

How Did “Typical” Ornithischian Dentition Develop?

Writing in the academic, on-line journal “PeerJ”, the researchers from Jilin University and the University of Alberta, describe how thin slices were taken from five jaw bones of this dinosaur so that teeth in the jaw could be studied.  In addition, the slices once polished to show their internal structure, would help the researchers determine tooth composition and to see how the teeth are maintained throughout the life of this little dinosaur.  Changchunsaurus makes a good candidate for this type of work, as it is known from numerous skulls (albeit, some of them are quite distorted), and it is regarded taxonomically as being close to origins of the Ornithopoda.

One of the Skulls of Changchunsaurus parvus Used in the Study

The holotype of Changchunsaurus parvus.

Image of the skull of the holotype specimen of C. parvus (JLUM L0304-j-Zn2).  The skull is shown in lateral view and the yellow shaded area indicates the area of the jaw from which the samples were taken.  Scale bar = 2 cm.

Picture Credit: Chen et al (PeerJ)

A Unique Method of Tooth Replacement

Among the notable features of Changchunsaurus parvus dentition is a unique method of tooth replacement that allowed this herbivore to recycle teeth without disrupting the continuous shearing surface formed by its tooth rows.  This permitted Changchunsaurus to have an efficient tooth-grinding surface all the time, thus helping it to process tough plant material.  The scientists also discovered that the teeth feature wavy enamel, a tissue type formerly thought to have evolved only in more derived members of the Ornithopoda.  The wavy enamel of Changchunsaurus is the phylogenetically earliest occurrence of this type of tissue known.

A Section of Dentary (Lower Jaw) Sample Along with Cross-sections of Teeth Showing Morphology

Changchunsaurus tooth morphology.

(B) a partial dentary showing the area cross-sectioned and magnified cross-sections of teeth (C to F) identifying teeth replacement and tooth morphology.

Picture Credit: Chen et al (PeerJ)

The picture above shows (B), an image of one of the partial lower jaws used in this research.  The purple line shows the plane of sectioning.  A whole view image of one of the thin sections through the lower jaw is shown (C) and (D) shows a magnified view of the process of tooth replacement.  Images (E) and (F) show highly magnified views of identified wavy enamel on the crown of replacement teeth (labial and lingual margins).

Commenting on the significance of this study, lead author Professor Chen Jun stated:

“These tissue-level details of the teeth of Changchunsaurus tell us that their teeth were well-adapted to their abrasive, plant-based diets.  Most surprisingly, the wavy enamel described here, presumably to make it more resistant to wear, was previously thought to be exclusive to their giant descendants, the duckbilled dinosaurs.”

This research contradicts previous interpretations that this type of wavy enamel arose in association with more complex hadrosauroid dentitions.  In view of its early appearance, the research team suggests that wavy enamel may have evolved in association with a shearing-type dentition in a roughly symmetrically-enamelled crown, although its precise function still remains somewhat of a mystery.

The authors suspect these features may have arisen early on in the Ornithopoda as they became adapted to herbivory, having to process tough vegetation.

The scientific paper:

“Tooth Development, Histology, and Enamel Microstructure in Changchunsaurus parvus: Implications for Dental Evolution in Ornithopod Dinosaurs” by Jun Chen , Aaron R. H. LeBlanc , Liyong Jin, Timothy Huang and Robert R. Reisz published in PeerJ.

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