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9 04, 2020

Massospondylus Eggs Give Up Their Secrets

By | April 9th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Dinosaur Eggs from the Late Triassic Reveal Their Contents

Researchers from the University of Witwatersrand (Johannesburg, South Africa), have utilised the high-powered and intense energy of the European Synchrotron Radiation Facility (ESRF), located at Grenoble in France to unscramble the embryonic development of dinosaurs.  The study, published in the journal “Scientific Reports”, demonstrates that dinosaur embryos show many similarities to the embryonic development of their living archosaurian relatives – birds and crocodiles.  In addition, the scientists found that in the dinosaur studied (the Sauropodomorpha Massospondylus carinatus), a set of simple teeth developed, in addition to the teeth the animal would have when it hatched.  These simple teeth (null-generation teeth), were either reabsorbed into the jawbone or shed prior to the animal breaking out of the egg.  This anatomical trait is found in crocodiles and lizards such as geckos (Order Squamata).

A Computer Generated Image of a Massospondylus Embryo Showing the Skull Bones

Synchrotron analysis to reconstruct dinosaur embryos.

Identifying the skull bones of Massospondylus carinatus using synchrotron analysis.  The individual bones of the tiny skull have been highlighted in different colours.

Picture Credit: Dr Kimberley Chapelle (University of Witwatersrand)

Lizards are not members of the Archosauria, they are not closely related to dinosaurs (nor to birds or crocodiles for that matter), this suggests that the production of null-generation teeth that are lost prior to hatching is an embryonic trait which is basal within the Class Reptilia and that, in essence, the embryonic developmental pattern in reptiles was established early in their evolutionary history.

Digitally Reconstructing the Skulls of Baby Dinosaurs

In the study, led by Dr Kimberley Chapelle and Professor Jonah Choiniere of the Evolutionary Studies Institute, based at the University of Witwatersrand, three-dimensional, computer generated images were created of the less than 2 cm long skulls of the embryonic dinosaurs.  The clutch of eggs was discovered in 1976 at a location within the Golden Gate Highlands National Park (Free State Province), the fossil specimens represent some of the oldest dinosaur eggs known to science.

The Clutch of Massospondylus Eggs Discovered in 1976 (Free State Province)

Clutch of Massospondylus carinatus eggs discovered in 1976

The clutch of Massospondylus carinatus eggs discovered in 1976 and the subject of the new scientific paper.

Picture Credit: Brett Eloff

Amongst the Rarest of Dinosaur Fossils

The fossilised remains of dinosaur embryos are among the rarest of all vertebrate fossils.  However, if palaeontologists can study them, then they can provide unique insights into the development of baby dinosaurs and permit comparison with the development of living archosaurs such as birds and crocodiles.  The powerful X-rays generated by the synchrotron allowed the researchers to obtain extremely detailed images of the fragile contents of the eggs, in what is a non-destructive technique.  The study commenced in 2015, when the fossils were transported to the ESRF at Grenoble.  It took nearly three years to process all the data generated back at the University, but the work was worth it as the scientists were able to reconstruct the delicate, tiny skulls of the dinosaurs in exquisite detail.

The fossil specimens were scanned at an unprecedented level of detail, the team were able to define and map individual cells within the fossilised bone.

Views from Various Angles of the Tiny Skull of a Massospondylus Embryo

The skull of a Massospondylus embryo.

Views of the skull of an embryonic Massospondylus.  It took 3 years to process all the data generated from the synchrotron X-ray scans.

Picture Credit: University of Witwatersrand/Scientific Reports

Working Out the Developmental Age of the Dinosaur Embryos

It had been thought that the fossilised Massospondylus eggs represented a clutch that had perished just prior to hatching.  An analysis of the state of the skull bones and direct comparison with the development stages of crocodile, chicken, turtle and lizard embryos revealed that the Massospondylus embryos were much younger than previously thought.  These dinosaur babies were only 60% of the way through their incubation.  This makes them some of the ontogenetically youngest dinosaur embryos known.  All other dinosaur embryos in the literature with ontogenetic age estimates are believed to represent dinosaurs in the last third of their development in the egg or close to hatching.

Hatching Massospondylus Dinosaurs in the Late Triassic of South Africa

Massospondylus nesting site - life reconstruction.

Massospondylus (basal Sauropodomorpha) nesting site.  The study provided new information on  how to estimate the ontogenetic age of dinosaur embryos.

Picture Credit: Julius Csotonyi

The Discovery of Null-generation Teeth in Dinosaur Embryos

Furthermore, the researchers discovered that each tiny embryo had two types of teeth preserved in its developing jaws.  One set was very similar to the teeth associated with Massospondylus adults, the second set consisted of tiny, very simple triangular teeth that were either reabsorbed into the jaw or shed prior to hatching.  These types of teeth are referred to as null-generation teeth and they are found in crocodilians and some types of extant lizard embryos such as geckos.

An Illustration of the Tooth Crowns of an Adult Massospondylus

Adult Massospondylus dinosaur teeth.

The teeth of an adult Massospondylus dinosaur.  The teeth of Massospondylus are proportionately quite long and the crowns end in a broad, leaf-shaped structure with distinctive ridges on their tips and sides.

Picture Credit: Everything Dinosaur from Gow et al (University of Witwatersrand)

Commenting on the discovery of null-generation teeth in the jaws of the dinosaur embryos, lead author, Dr Chapelle stated:

“I was really surprised to find that these embryos not only had teeth, but had two types of teeth.  The teeth are so tiny, they range from 0.4 to 0.7 mm wide.  That’s smaller than the tip of a toothpick!”

The scientists conclude that dinosaurs developed in their eggs in very similar ways as extant archosaurs, so what we know about the development of birds and crocodiles in the egg can be confidently applied to extinct archosaurs such as dinosaurs and pterosaurs too.  The development traits shared with members of the Squamata Order (lizards and snakes) would permit these findings to be applied generally to a much wider variety of extinct reptiles, such as those assigned to the Lepidosauria clade, the sister clade to the Archosauria, reptiles on a different branch of the Reptilia family tree.

Synchrotron Analysis Likely to Lead to Further Insights into Dinosaur Development

The research team hope to utilise the thousands of scans they have amassed to better understand the post-cranial development of sauropod dinosaurs.  They will be examining the rest of the skeleton of the Massospondylus embryos to see if this dinosaur shares similarities in development with extant archosaurs.  The scientists hope to shed further light on how these dinosaurs moved about when they first emerged from the nest.  Palaeontologists think that these types of dinosaurs hatched as bipeds before adopting a quadrupedal stance as these animals grew and matured.

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

The scientific paper: “Conserved in-ovo cranial ossification sequences of extant saurians allow estimation of embryonic dinosaur developmental stages” by Kimberley E. J. Chapelle, Vincent Fernandez and Jonah N. Choiniere published in Scientific Reports.

6 04, 2020

Homo heidelbergensis Younger Than Previously Thought

By | April 6th, 2020|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Dating the Broken Hill Skull – H. heidelbergensis Younger than Previously Thought

Palaeoanthropologists have long recognised that the evolution of the hominins and our own species (Homo sapiens), was complicated and not simply a linear transgression from one species to another.  Human fossil remains are exceptionally rare and sometimes, a new study can upend previously assumed concepts and ideas.  For example, a team of scientists including researchers from the Natural History Museum (London), Australian National University (Canberra), University College Dublin, Muséum national d’Histoire naturelle (Paris), University of the Free State (South Africa), University of Wollongong (Queensland), University of Southampton and Griffith University (Queensland), have published new dating information for a hominin skull discovered in 1921.

The skull representing Homo heidelbergensis turns out to be much younger than previously thought.

The Famous Broken Hill Skull (Kabwe 1) Homo heidelbergensis

The famous H. heidelbergensis skull (Kabwe 1).

Views of the Broken Hill Skull (Kabwe 1).  Left lateral view (A) and anterior view (B).

Picture Credit: The Trustees of the Natural History Museum

Writing in the academic journal “Nature”, the researchers conclude that this skull, previously thought to be around half a million years old, was much younger with an estimated date of between 274,000 and 324,000 years of age.  This result suggests that in the later stages of the Middle Pleistocene of Africa (Chibanian stage), there were many different types of hominin living at the same time.  Homo sapiens, H. heidelbergensis/H. rhodesiensis and Homo naledi were all contemporaneous.

The Broken Hill Skull

The skull studied, referred to as the Broken Hill specimen, currently resides in the collection of the Natural History Museum (London) and is on display in the Human Evolution gallery, but there are ongoing discussions about the return of this fossil to Africa.  The skull was discovered in 1921 by an African miner and his Swiss co-worker Tom Zwigelaar at the lead and zinc mine located at Broken Hill, which at the time was in northern Rhodesia but is now Kabwe in Zambia, hence the reference to the fossil skull as Kabwe 1.  Other fragmentary human remains were also found at the mine (partial upper jaw, tibia, sacrum and two elements from a femur from another individual).  The fossils were donated by the mining company to the then British Museum (Natural History Museum), at the time of their discovery anthropologists regarded these fossils as the most significant hominin fossils found on the African continent.

Early Photographs of Kabwe 1 (Broken Hill Skull)

Original photographs of the Broken Hill skull (Homo heidelbergensis).

Original photographs of the Broken Hill skull (H. heidelbergensis).

Picture Credit: Griffith University (Queensland)

Problems Dating the Skull and Fossil Bones

Nearly a hundred years ago, data recording surrounding such an important fossil discovery was nowhere near as thorough at it is today.  Mining work continued in the area where the skull and other bones had been found so any evidence to help accurately date the fossils was subsequently lost.  Assigned to Homo heidelbergensis, the skull was originally dated to around 500,000 years ago.  However, these researchers, led by Professor Rainer Grün (Environmental Futures Research Institute at Griffith University), subjected the skull and the other hominin fragments from the site to radiometric dating and determined that these people lived between 274,000 and 324,000 years ago.

Commenting on the importance of this research, Professor Grün stated:

“The new best age estimate of the fossil impacts our understanding of the tempo and mode of modern human origins”.

One of the co-authors of the scientific paper, Professor Chris Stringer (Natural History Museum), added:

“Previously, the Broken Hill skull was viewed as part of a gradual and widespread evolutionary sequence in Africa from archaic humans to modern humans.  But now it looks like the primitive species Homo naledi survived in southern Africa, H. heidelbergensis was in Central Africa, and early forms of our species existed in regions like Morocco and Ethiopia.”

Homo rhodesiensis and Piltdown Man

It was Sir Arthur Smith Woodward, the curator of the Geology Department at the British Museum who proposed the new species Homo rhodesiensis to describe the Kabwe 1 skull as “Rhodesian Man”.  However, most scientists now consider H. rhodesiensis to be junior synonym of H. heidelbergensis or possibly an African sub-species of it.  Despite a prestigious academic career, Sir Arthur is best remembered for his association with the Piltdown Man hoax of 1912.  Even on his deathbed, he still believed that the fossil remains found in a Sussex gravel bed at Barkham Manor, near to Piltdown Common, represented a species of archaic human, unlike any other species of early hominin known to science.  Unfortunately, for Sir Arthur, five years after he died, new dating techniques proved the human skull bones from the site to be less than 500 years old.

The new, younger date for the Kabwe 1 skull also casts a cloud over the provenance of stone tools associated with hominin fossils from the late Middle Pleistocene.  As scientists have evidence to indicate Homo heidelbergensis present in Africa as recently as 300,000 years ago, stone tools from this date may not have been crafted by our species.

Not All the African Stone Tools Around 300,000 Years of Age Can be Ascribed to our own Species

Heidelbergensis flint spear.

Crafted with considerable skill – a flint spear point associated with Homo heidelbergensis.  The much younger age of the Kabwe 1 specimen casts doubts about which species made the stone tools associated with Middle Pleistocene hominin fossils.

Picture Credit: Dr Nicholas Conrad/University of Tubingen

The new age estimate for Kabwe 1 raises questions about our own evolution.  It casts doubts on the presumption that H. heidelbergensis/H. rhodesiensis was a direct ancestor of our species Homo sapiens.  This research suggests that there were multiple contemporaneous hominin lineages in Africa during the later stages of the Middle Pleistocene, reflecting a similar model found in Eurasia.

  • African hominins (late Middle Pleistocene) – H. sapiens, H. nalediH. heidelbergensis/H. rhodesiensis
  • European/Asia hominins (late Middle Pleistocene) – H. neanderthalensis, H. luzonensis, H. floresiensis, the Denisovans and perhaps also H. heidelbergensis and H. erectus

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

The scientific paper: “Dating the skull from Broken Hill, Zambia, and its position in human evolution” by Rainer Grün, Alistair Pike, Frank McDermott, Stephen Eggins, Graham Mortimer, Maxime Aubert, Lesley Kinsley, Renaud Joannes-Boyau, Michael Rumsey, Christiane Denys, James Brink, Tara Clark and Chris Stringer published in Nature.

To read an article about the presence of H. heidelbergensis in Kent: Giant Prehistoric Straight-tusked Elephant Butchered by H. heidelbergensis.

26 03, 2020

Late Cretaceous Southern United States Had “Raptors” Too

By | March 26th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Dineobellator notohesperus – A Velociraptorine with Extra Attitude!

Scientists have described a new species of “raptor” from the Late Cretaceous of New Mexico.  Described from fragmentary remains, this two-metre-long carnivore was related to Velociraptor.  It may have been roughly the same size as the Mongolian genus, but it probably was even more agile with a stronger grip.  Its discovery suggests that the dromaeosaurids were diversifying right up to the end of the Age of Dinosaurs.

Life Reconstruction Dineobellator notohesperus (Maastrichtian of New Mexico)

Dineobellator Life Reconstruction

A trio of the newly described dromaeosaurid from the Late Cretaceous of New Mexico (Dineobellator) gather at a waterhole.  The titanosaur Alamosaurus passes by in the background and in the distance a tyrannosaur is approaching.

Picture Credit: Sergey Krasovskiy

Writing in the academic journal “Scientific Reports”, the researchers from The University of Pennsylvania and the New Mexico Museum of Natural History and Science, describe a partial, skeleton excavated from the Bisti/De-na-zin Wilderness of New Mexico, found within a few metres above the base of the Naashoibito Member.  The coarse sandstone deposits are notoriously difficult to date, these sediments were deposited towards the end of the Cretaceous between 70 and 66.3 million years ago (Maastrichtian faunal stage).

Fossil material includes parts of the skull, elements from the jaws, fragments of vertebrae, tail bones (caudal vertebrae), one rib with other pieces of rib and limb bones including a nearly complete right upper arm bone (humerus) and a nearly complete right ulna (bone from the forearm).  The first fossilised remains were found in 2008, subsequent field work carried out in 2009, 2015 and 2016 yielded more fossil material, mostly very fragmentary in nature.  It is believed all the fossil material, including a claw from the right hand, represents the remains of a single dinosaur.

A Skeletal Reconstruction of Dineobellator notohesperus

Known fossil material and skeletal reconstruction of Dineobellator.

A silhouette and postulated skeleton of Dineobellator (known fossil material in white).

Picture Credit: Jasinski et al/Scientific Reports

A Small but Dangerous Dinosaur

Dineobellator notohesperus is the first dromaeosaurid to be described from the southern United States.  It would have lived in the south of the Cretaceous landmass of Laramidia.  Although no evidence of feathers has been found, the ulna shows evidence of a row of small rounded pits in the bone, interpreted as anchor points for large feathers on the arm (ulna papillae).  Analysis of the forelimbs suggest that Dineobellator had stronger arms with a more powerful grip.  A study of the tail bones suggest that the tail had greater movement which would have made this dinosaur adept at making sharp turns and agile changes of direction.  The researchers suggest these anatomical traits provide an insight into how this small theropod hunted and behaved.

The researchers, which include Dr Steven Jasinski (Department of Earth and Environmental Science, University of Pennsylvania), postulate that Dineobellator was an active predator that occupied a discrete ecological niche in the food chain whilst living in the shadow of Tyrannosaurus rex.  The newest North American “raptor” Dineobellator notohesperus is pronounced dih-nay-oh-bell-ah-tor noh-toh-hes-per-us and the genus name comes from the native Navajo word “Diné”, a reference to the Navajo Nation and the Latin word “bellator” which means warrior.  The trivial name has been erected to acknowledge the location of the fossil find.  The word “noto” is from the Greek meaning southern and “hesper” the Greek for western.  This is an acknowledgement that Dineobellator roamed the south-western part of the United States.  In addition, Hesperus is a reference to a Greek god, the personification of the evening star (Venus) and by extension “western”.

Dr Jasinski has already had a considerable impact on the Dromaeosauridae family.  Back in 2015, Everything Dinosaur reported on the formal description of Saurornitholestes sullivani, a dinosaur named by Steven Jasinski whilst a PhD student at the University of Pennsylvania.  To read more about S. sullivaniSniffing Out a New Dinosaur Species.

An Illustration of Saurornitholestes sullivani

Saurornitholestes sullivani illustrated

An agile dinosaur, an illustration of Saurornitholestes sullivani.  Although the fossil material associated with this species was found in New Mexico, S. sullivani lived several million years earlier than Dineobellator notohesperus.

Picture Credit: Everything Dinosaur

A Tough Life for a Tough Dinosaur

A phylogenetic analysis undertaken by the research team places Dineobellator within the Velociraptorinae subfamily of the Dromaeosauridae.  Other Maastrichtian “raptors” known from North America are few and far between (Acheroraptor and Dakotaraptor – both from the Hell Creek Formation).  The discovery of Dineobellator suggests that dromaeosaurids were still diversifying at the end of the Cretaceous and as an velociraptorine, its fossils lend further weight to the idea that faunal interchange between Asian and North American dinosaurs took place sometime during the Campanian/Maastrichtian.

It is not known whether Dineobellator notohesperus was a pack hunter.  The fossilised remains do indicate that this was one very tough dinosaur but it did not have everything its own way.  A rib shows a deformity, suggesting that this bone was broken, but the animal suffered this trauma a while before it died as the break is healed.  Intriguingly, the scientists identified a prominent gouge mark preserved on the hand claw (manual ungual).  This gouge mark, which measures nearly a centimetre long, terminates in a small depression.  The scientists suggest that this damage was not caused by disease or by any process associated with the preservation of the fossil bones.  The team suggest that this was an injury that occurred close to, or at the time of this dinosaur’s demise.

The researchers speculate that this Dineobellator received an injury in a fight with another Dineobellator or perhaps this damage to its hand claw was inflicted upon it by another type of predatory theropod.

Views of the Hand Claw of  Dineobellator notohesperus Showing Damage Interpreted as a Wound Inflicted by Another Theropod Dinosaur

The manual ungual of Dineobellator.

Views of the hand claw of Dineobellator.  The right manual ungual of Dineobellator notohesperus (I) lateral view, with (J) a silhouette of the transverse plane of the right manual ungual near the distal end.  Image (K) shows the claw in media view with the dashed area highlighted in (K) showing the gouge mark (L).  The red arrow indicates the pathology.  Scale bars equal 1 mm, please note (L) is not to scale.

Picture Credit: Jasinski et al/Scientific Reports with additional annotation by Everything Dinosaur

The scientific paper: “New Dromaeosaurid Dinosaur (Theropoda, Dromaeosauridae) from New Mexico and Biodiversity of Dromaeosaurids at the end of the Cretaceous” by Steven E. Jasinski, Robert M. Sullivan and Peter Dodson published in Scientific Reports.

23 03, 2020

Discovery of the Oldest Bilaterian – Ikaria wariootia

By | March 23rd, 2020|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Meet Your Oldest Ancestor – Ikaria wariootia 

A team of international scientists have identified the first ancestor of animals that show bilateral symmetry, in ancient marine sediment around 555 million years old.  Palaeontologists had predicted that such an organism would be identified in Ediacaran sediments, essentially a creature with a body plan that has been adopted by the majority of the Kingdom Animalia, now thanks to the use of sophisticated three-dimensional laser scans funded by NASA, the “smoking gun” evidence has been found.

A Life Reconstruction of the Earliest Bilaterian Known to Date (I. wariootia)

Ikaria wariootia the earliest known bilaterian.

Ikaria wariootia life reconstruction.

Picture Credit: Sohail Wasif/University California Riverside

Ikaria wariootia – The Size of a Rice Grain but a Big Discovery!

Writing in the journal “Proceedings of the National Academy of Sciences of the United States of America”, the researchers, which included scientists from University California Riverside and the South Australian Museum, examined tiny trace fossils, essentially burrows and borings into an ancient Ediacaran seabed (Ediacara Member, South Australia).  Proximal to some of these traces were very small oval impressions.  Thanks to funding from a NASA exobiology grant, the team were able to employ a sophisticated three-dimensional laser scanner to map these depressions in the ancient rock.  Computer-generated images revealed a worm-like organism with a cylindrical body and faintly grooved musculature.  A distinct head and tail were also identified.  This little animal represents the earliest bilaterian, a hugely significant step in the evolution of life on Earth.

The transition from simple, microscopic forms of life to the abundance and variety of complex creatures in the Cambrian remains quite poorly understood.  However, the beautifully preserved remains of soft-bodied organisms, many of which look like nothing alive today, associated with the ancient strata of the Ediacara Hills of South Australia have permitted palaeontologists the opportunity to learn about life on our planet prior to the evolution of hard body parts such as shells and exoskeletons.  Many of the creatures identified from their fossils had bizarre body forms such as the circular Dickinsonia (below), but scientists had predicted that animals with bilateral symmetry would be present in this ecosystem, it was just a question of finding them.

A Circular Impression of an Organism from the Ediacara Hills (South Australia) – Dickinsonia costata Fossil

Dickinsonia costata fossil.

The Ediacaran fossil Dickinsonia costata, specimen P40135 from the collections of the South Australia Museum.

Picture Credit: Dr Alex Liu (Cambridge University)

The development of bilateral symmetry was a critical step in the evolution of animal life, giving organisms the ability to move purposefully and a common, yet successful way to organise their bodies.  In the scientific paper, the research team describe Ikaria wariootia as ranging in size between 2 and 7 millimetres in length and being around 1 to 2.5 millimetres wide.   The largest specimens were about the size of a grain of rice, just the right size to have made the burrows and borings (trace fossils).

The discovery of Ikaria wariootia is consistent with predictions based on modern animal phylogenetics, that the last ancestor of all bilaterians was simple and small and represents a rare link between the Ediacaran and the subsequent record of animal life.  Put simply, I. wariootia is on the same part of the animal family tree as the majority of animals alive today and that includes us (Homo sapiens).

Ikaria wariootia Impressions Preserved in Ancient Marine Sediment

Ikaria wariootia impressions.

Ikaria wariootia impressions preserved in ancient marine sediments.

Picture Credit: Droser Laboratory/University of California Riverside

Commenting on the significance of the discovery, one of the authors of the scientific paper, Scott Evans (University of California Riverside), stated:

“We thought these animals should have existed during this interval [Ediacaran], but always understood they would be difficult to recognise.  Once we had the 3-D scans, we knew that we had made an important discovery.”

Analysis of modern animals and Ediacaran trace fossils predicted that the oldest bilaterians would be very small with simple body plans.  The research team found that the size and shape of Ikaria matched the predictions that had been made with regards to the maker of the trace fossil Helminthoidichnites, indicating sediment displacement and purposeful animal movement.  Importantly, in the Ediacara Member, Helminthoidichnites occurs stratigraphically below classic Ediacara body fossils such as Dickinsonia.  Together, these suggest that Ikaria represents one of the oldest total group bilaterians identified to date, with very little deviation from the characters and traits predicted for their last common ancestor.

In addition, these trace fossils persist into the Phanerozoic Eon (from the Cambrian Period onwards),  providing a critical link between the Ediacaran and Cambrian biota.

A Three-Dimensional Laser Image of a Scan of a Rock Depression Revealing the Body Plan of Ikaria wariootia

Three-dimensional laser scan of an Ikaria wariootia impression.

A three-dimensional laser scan of an Ikaria wariootia impression.

Picture Credit: Droser Laboratory/University of California Riverside

What’s in a Name?

The genus name comes from Ikara, which means “meeting place” in the local Adnyamathanha dialect.  It is the Adnyamathanha term for a grouping of mountains known as Wilpena Pound.  The trivial name comes from Warioota Creek, which runs from the Flinders Ranges to Nilpena Station in the Ediacara Hills.  It may look a fairly simple animal to us, but back in the Ediacaran Ikaria was one of the most complex organisms around.  It burrowed in thin layers of well-oxygenated sand on the ocean floor in search of organic matter, indicating rudimentary sensory abilities.  The depth and curvature of Ikaria represent clearly distinct front and rear ends, supporting the directed movement found in the burrows.  The walls of the burrows preserve evidence of “v-shaped” ridges, which indicate that Ikaria moved by contracting muscles across its body like an earthworm.  This is known as peristaltic locomotion.

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

The scientific paper: “Discovery of the oldest bilaterian from the Ediacaran of South Australia” by Scott D. Evans, Ian V. Hughes, James G. Gehling and Mary L. Droser published in the Proceedings of the National Academy of Sciences of the United States of America.

19 03, 2020

Canadian Fish Fossil Lends Palaeontologists a Helping Hand

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

Fish Fossil Helps to Demonstrate How Fins Turned into Hands

A team of international scientists including researchers from Flinders University in Adelaide (South Australia) and the Université du Québec à Rimouski (Canada), have scanned the fossilised remains of an ancient fish with tetrapod tendencies to reveal evidence of how the limbs of fish evolved into the terrestrial appendages of land animals.  The fossilised remains date from the Late Devonian and are approximately 380 million years old.  The fossil is a specimen of Elpistostege (E. watsoni), the discovery of a much more complete skeleton of this strange animal gave the researchers the opportunity to analyse the body plan of this predator in much greater detail than previously.

A Near Complete Specimen of Elpistostege watsoni with Accompanying Line Drawing

Elpistostege watsoni fossil with interpretive drawing and life reconstruction.

The near complete Elpistostege specimen with line drawing showing the outline of the skeleton and a life reconstruction.  The research was conducted on a fossil specimen that had been discovered in 2010.

Picture Credit: South Australia Leads/Flinders University

Strategic Professor in Palaeontology (Finders University), Professor John Long, announced the discovery of the near complete fossil specimen in the journal “Nature”.  Commenting on the significance of the fossil find, he stated that the specimen “reveals extraordinary new information about the evolution of the vertebrate hand.”

High Energy X-Rays to Assess Fin Structure

The research team bombarded the fossil specimen with high energy X-rays to reveal the presence of limb and wrist bones hidden in the fins.  Evidence of finger-like bones could also be made out.

The Professor added:

“This is the first time that we have unequivocally discovered fingers locked in a fin with fin-rays in any known fish.  The articulating digits in the fin are like the finger bones found in the hands of most animals.  This finding pushes back the origin of digits in vertebrates to the fish level and tells us that the patterning for the vertebrate hand was first developed deep in evolution, just before fishes left the water.”

A Life Reconstruction of the Late Devonian Elpistostege

Elpistostege life reconstruction.

A life reconstruction of Elpistostege.

Picture Credit: Miguasha National Park/Johanne Kerr and François Miville-Deschênes

The high resolution scans revealed the presence of a humerus (upper arm bone), the radius and ulna (the two bones from the forearm), carpal bones from the wrist and the presence of bones that resembled digits.  The fossil specimen measures 1.57 metres in length.  It comes from exposures of the Escuminac Formation located in the Canadian province of Quebec.  The strata represent a brackish water, estuarine environment and palaeontologists have long speculated that such a habitat may have been one of the driving forces behind the evolution of limbs capable of terrestrial locomotion in certain types of ancient fish.  The teeth in the broad jaw suggest that Elpistostege was an apex hypercarnivore, but whether it fed on other fish or ventured out onto land to grab insects and arthropods on the shore (as indicated by the position of the eyes at the top of the head suggesting an ambush predator), remains unknown.

Co-author of the scientific paper Richard Cloutier (Université du Québec à Rimouski), commented that over the last ten years or so, fossils representing the fish-to-tetrapod transition had helped palaeontologists to gain a better understanding about this important stage in vertebrate evolution.

He added:

“The origin of digits relates to developing the capability for the fish to support its weight in shallow water and for short trips out on land.  The increased number of small bones in the fin allows more planes of flexibility to spread out the weight through the fin.”

In previous studies, Dr Cloutier had postulated that Elpistostege might represent the most primitive tetrapod known to science, an accolade currently held by the closely related Tiktaalik, fossils of which come from northern Canada (Ellesmere Island).

Australian Professor John Long has dedicated much of his academic career to studying Devonian fish and the early stages of the evolution of the modern tetrapod body plan.

Here are some blog articles that provide more details of his research: The Early Evolutionary History of Sharks.

A Placoderm “Platypus”: Ancient Placoderm from Australia.

15 03, 2020

Casting Doubt over Oculudentavis

By | March 15th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Is Oculudentavis a Member of the Archosauria?

On the 11th March (2020), Everything Dinosaur posted up a blog article featuring the discovery of a remarkably well-preserved fossil skull that had been found in amber from northern Myanmar.

To read our blog post: Hummingbird-sized Dinosaur from Burmese Amber.

Following publication, a number of academics have questioned the conclusions made by Xing et al with regards to this fossil representing a member of the Maniraptora.  It is certainly true that the validity of the interpretation of the fossil skull as maniraptoran has subsequently been challenged post publication (Wang Wei et al).  They comment that the shape of the skull is not unique to archosaurs, many lizards for example, show similar characteristics, the phylogenetic analysis is questioned, along with the apparent absence of an antorbital fenestra (an opening in the skull of all known archosaurs between the orbit and the naris).

The Very Bird-like Skull of Oculudentavis khaungraae But Can Appearances be Deceptive?

Oculudentavis khaungraae computer generated image of the skull.

Oculudentavis khaungraae computer generated image of the skull (left lateral view).

Picture Credit: Xing et al (Nature)

It is suggested that the skull actually comes from a lizard and that the specimen is not from an archosaur at all.

The original publication noted that the spoon-shaped bones that make up the sclerotic ring were reminiscent of that seen in the eye sockets of lizards.  Scleral bones of this shape have never been found in a dinosaur or a bird, it is suggested that these bones support the idea that the fossil is that of a lizard and not a member of the Archosauria.

Trouble with the Teeth

The roots of the tiny teeth do not seem to be located in sockets in the jawbone (thecodont dentition).  This was a peculiar feature remarked upon by a number of academics once this paper had been widely circulated.  Teeth located in sockets is a characteristic of toothed-archosaurs such as crocodilians and the dinosaurs.  Other types of tetrapod also show this tooth morphology, but in Oculudentavis the teeth are not in sockets but either fused to the jaw (acrodont dentition) or located within grooves that can be found along the length of the jaw bones (pleurodont dentition).

The number of teeth in the jaw far exceeds that known for any type of ancient bird.  The tooth line extending under the eye-socket (orbit), is also highly unusual.  Such anatomical traits are associated with the Squamata (lizards and snakes), not with the Archosauria.

These arguments (along with others, such as the absence of feathers), have led some scientists to question the conclusions made in the original Nature publication.  Oculudentavis might not be a bird or a dinosaur, it might represent the preserved remains of a lizard.

An Anolis Lizard (A. equestris) Displaying its Throat Sac

Is the skull that of a lizard?

An Anolis lizard, note the long snout, large eyes and the jaw that extends under the orbit.

Picture Credit: Everything Dinosaur

The scramble to publish can sometimes lead to a lack of peer review opportunities and a foreshortening of pre-publication correspondence amongst academics.  When the “Nature” paper was published it certainly created a great deal of interest in the wider media.  Sadly, we suspect that any challenge to the original paper’s conclusions or subsequent revision will not attract anywhere near as much publicity.

We shall await developments.

Perhaps, in future we could refer to such controversies as “Oculudentavism”

13 03, 2020

Telling the Time in the Late Cretaceous

By | March 13th, 2020|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Fossil Clam Helps Scientists to Tell the Time

Researchers from the Vrije Universiteit Brussel and the University of Ghent have used 70 million-year-old fossil bivalves to gain information about day length and seasonal variations during the Late Cretaceous.  Tyrannosaurids and duck-billed dinosaurs had days that were approximately 30 minutes shorter than ours, as a consequence of this their year was about a week longer.

Writing in the academic journal Paleoceanography and Paleoclimatology, the researchers conducted a series of tests on the fossilised shells of a type of bivalve (Torreites sanchezi).  The fossil was found on a mountainside in Oman, but back in the Campanian stage of the Late Cretaceous, this area was a shallow, subtropical sea.

Daily Growth Rings Preserved in Fossil Bivalves Can Provide Scientists with Data About Ancient Planetary Systems

Fossil bivalves can help scientists understand planetary systems.

The growth rings laid down by rudist bivalves can help scientists to better understand ancient planetary systems.  An example of a bivalve fossil (Spondylus) from the Cretaceous.  This type of bivalve evolved in the Early Jurassic and can still be found today in tropical seas.

Picture Credit: Everything Dinosaur

Laser Used to Bore a Hole in the Shell

Many types of molluscs grow quickly and they lay down discernible growth rings on their shells every day.  Scientists can conduct a series of tests on these markers and identify useful information about the climate and the environment in which the mollusc lived.  For example, using the growth rings, the researchers were able to determine that the fossil specimen died when it was around nine years of age.

A laser was used to bore a series of tiny holes in the shell, samples were taken and analysed for trace elements.  Using this information, the scientists were able to gain information on the temperature and the chemistry in the sea water in the reef environment where the mollusc lived.  The marine temperatures fluctuated between summer and winter, with a peak of around 40 ˚ Celsius in summer and 30 ˚ Celsius in winter.  The average annual sea temperatures were warmer than previously thought.

The Rings on the Bivalve Shell Can Provide a Lot of Information

Fossil Bivalves provide dating data.

Microscopic analysis of the fossil shell can help scientists work out day length and seasonal variations in the past.

Picture Credit: Niels de Winter et al

In addition, the scientists determined that the bivalve grew much faster during the day than it did at night.  This phenomenon is not uncommon with bivalves today, some species form symbiotic relationships with algae, it is thought that the Cretaceous species was in a similar relationship.  A combination of counting layers, spectral analysis of chemical cyclicity and chemical layer counting shows that the mollusc laid down 372 daily laminae per year, demonstrating that length of day has increased since the Late Cretaceous, as predicted by numerous astronomical models and previous studies of fossil molluscs.  However, this study represents the most accurate assessment of seasonal growth, day length and annual environmental changes recorded in a fossil from the Late Cretaceous.

The Earth’s orbit around the sun does not alter that much, the extra 7 days recorded in a year, are not really a record of the Earth taking longer to make its orbit, but a reflection of the fact that the Earth was spinning faster on its axis 70 million years ago.  With the Earth turning faster, a day was slightly shorter compared to what we experience in the 21st century.  A day in the Cretaceous would have lasted approximately 23 1/2 hours.

An Explanation – Why is the Rotation of the Earth Slowing Down?

The Earth’s orbit around the sun does not change a great deal, but the length of a day on Earth has been steadily increasing since our planet and its moon were formed.  The moon’s gravity is acting on our planet, it creates friction from ocean tides and this is gradually slowing the Earth’s rotation.  At the same time, Earth’s own gravity is having an effect on the moon.  The pull of the tides accelerates the moon, so the satellite is being pushed away from our planet.  When the Torreites sanchezi bivalve was alive, a dinosaur on the beach at night would have seen a moon that looks bigger than the one we see today, it was several thousand metres closer to Earth.

The research team conclude that as bivalve shell calcite preserves quite well, this study permits further work using other fossils to determine seasonality, marine temperatures and day length.  This should help to document environmental change in warming ecosystems and widen our understanding of the magnitude of short‐term changes during greenhouse climates.

The scientific paper: “Subdaily-Scale Chemical Variability in a Torreites sanchezi Rudist Shell: Implications for Rudist Paleobiology and the Cretaceous Day-Night Cycle” by Niels J. de Winter, Steven Goderis, Stijn J.M. Van Malderen, Matthias Sinnesael, Stef Vansteenberge, Christophe Snoeck, Joke Belza, Frank Vanhaecke, and Philippe Claeys published in Paleoceanography and Paleoclimatology.

12 03, 2020

Scottish Stegosaurs

By | March 12th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Scottish Island – A Dinosaur Stomping Ground Complete with Stegosaurs

Scientists led by researchers from Edinburgh University have reported the discovery of dozens of dinosaur footprints preserved in exposed mudstones at two locations on the Isle of Skye.  The trace fossils preserve evidence of a variety of different types of dinosaurs, which helps palaeontologists to gain a better understanding of dinosaur distribution and diversity during the Middle Jurassic.

The tracks indicate a variety of dinosaur trackmakers, including bipedal theropods of various sizes, possible ornithopods and a quadrupedal ornithischian dinosaur, the tracks of which show a resemblance to the ichnotaxon Deltapodus, which is believed to represent a stegosaur.  If these prints do represent a member of the Stegosauria, then this is the first time that evidence for this type of armoured dinosaur has been discovered on the Isle of Skye.

Dinosaurs Congregating Around Mudflats on the Isle of Skye (Middle Jurassic)

Dinosaurs on a mudflat (Isle of Skye).

Life reconstruction of the Isle of Skye mudflat.  Note no sauropod tracks have been identified to date at the two sites described in the newly published scientific paper.

Picture Credit: Jon Hoad

Globally Important Fossil Discovery

During the Middle Jurassic the Dinosauria rapidly diversified and many new types evolved.  Unfortunately, the fossil record for terrestrial vertebrates from the Middle Jurassic is particularly poor.  The abundant trace fossils associated with the Isle of Skye are globally important, providing scientists with an opportunity to plot which types of dinosaurs are associated with this location.  Since the first dinosaur footprint in Scotland was found in the 1980’s numerous tracksites representing several ichnotaxa have been recorded.

Writing in the academic journal PLOS One, the researchers describe two new tracksites from Rubha nam Brathairean (Brothers Point).  The sites are referred to as BP1 and BP3, site BP2, which revealed sauropod and theropod prints has already been reported upon: Isle of Skye Steps into the Jurassic Spotlight (2018).

An Aerial View and Line Drawing of BP1 Showing the Distribution of the Dinosaur Tracks

BP1 site of dinosaur tracks (

Isle of Skye dinosaur tracks (BP1).  All three sites BP1, BP2 and BP3 were discovered between 2015 and 2017.

Picture Credit: PLOS One

An Insight into the Fauna Around a Subtropical Coastal Area

The trace fossils at both BP1 and BP3 were formed when mudflats were exposed and dinosaurs walked over them.  Today, the mudstones comprise part of the Lealt Shale Formation of the Great Estuarine Group.  The dinosaurs inhabited a coastal environment in what was a subtropical climate.  The fossil bearing rocks might be exposed on the coast today, but the climate on the Isle of Skye today is very different to what it was like around 170 million years ago.  The notorious Scottish weather prevented the researchers from using drones on several occasions in their attempts to photograph and map the sites.

An Aerial View of BP3 and Accompanying Line Drawing Showing the Various Dinosaur Tracks

Isle of Skye dinosaur tracks (BP3).

Skye dinosaur tracks (BP3).

Picture Credit: PLOS One

The tracks at both sites are preserved as impressions (concave epirelief) and the signs of mud cracks associated with the trace fossils suggest that the surfaces of both sites were briefly exposed before being quickly reclaimed by the return of brackish water.  Whilst the dinosaur tracks at BP3 were being mapped, an articulated pterosaur skeleton was found in the overlying limestone layer.  The state of the bones (largely unfractured) and the articulated skeleton suggest that the overlying limestone was deposited in a relatively low energy environment.  The pterosaur is currently being studied and will be covered in a future scientific paper.

Evidence of a Stegosaur

One of the tracks at location BP1 (BP1_Twy-01) shows a series of prints made by a quadrupedal dinosaur.  Although the tracks are a little distorted, distinctions between the pes (rear foot) and the manus (front foot) can be made.  The researchers conclude that these prints and other, single prints from this site are similar to the ichnotaxon Deltapodus.  Evidence of a potential armoured dinosaur from the Isle of Skye adds to the diversity of dinosaur types known from this location.

Mapping the Ornithischian Tracks (Potential Stegosaur – Ichnotaxon Deltapodus)

The quadrupedal trackway (BP1_Twy_01).

Potential Stegosaur tracks from the Isle of Skye.  The photograph (above) shows (a) an aerial overview of the site, (b) a line drawing showing the position of the tracks and (c), a false colour rendering of the tracks showing topography.

Picture Credit: PLOS One

Together these two new tracksites demonstrate the wide variety of different types of dinosaur present in the area and will help palaeontologists gain more data on the early evolution and radiation of the Dinosauria.  As the researchers conclude, essentially BP1 and BP3 provide a snapshot of a “day in the life” of a Middle Jurassic ecosystem.

A Palaeontological Puzzle

No sauropod tracks have been described to date from BP1 or BP3, although they have been found at BP2.  The absence of sauropod evidence could be coincidental or perhaps an indication that during the time the mudflats were exposed, these large herbivores were not present in the area.  Environmental factors could help to explain the absence of sauropods.  Site BP2 represents a shallow lagoon, whilst BP1 and BP3 represent mudflats.  The sauropods may have preferred to occupy the lagoons.

The scientific paper: “Novel track morphotypes from new tracksites indicate increased Middle Jurassic dinosaur diversity on the Isle of Skye, Scotland” by Paige E. dePolo, Stephen L. Brusatte, Thomas J. Challands, Davide Foffa, Mark Wilkinson, Neil D. L. Clark, Jon Hoad, Paulo Victor Luiz Gomes da Costa Pereira, Dugald A. Ross and Thomas J. Wade published in the journal PLOS One.

11 03, 2020

Hummingbird-sized Dinosaur from Burmese Amber

By | March 11th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Oculudentavis khaungraae – Tiny Fossil Skull Could Represent the Smallest Dinosaur

Team members at Everything Dinosaur had been aware that something big was brewing amongst those members of the academia with an interest in vertebrate palaeontology.  An academic paper published in the journal “Nature”, describes the beautifully preserved but very small skull of a theropod dinosaur preserved in Cretaceous amber from northern Myanmar (Burma).  The fossil might just represent the smallest dinosaur known to science.

The fossil might be tiny but this wonderful discovery could have very big implications when it comes to understanding how miniaturisation occurs within vertebrates.  It also provides yet another remarkable insight into the types of creatures that shared the Late Cretaceous with non-avian dinosaurs and pterosaurs.  Named Oculudentavis khaungraae it probably weighed about as much as the smallest living bird, the Bee Hummingbird (Mellisuga helenae), which weighs about two grammes, that is about half the weight of a single sheet of A4 paper.

The Polished Amber Nodule Reveals a Bounty of Preserved Material Including the Tiny Skull of Oculudentavis khaungraae

Oculudentavis khaungraae skull in amber.

Tiny fossil skull preserved in amber (Oculudentavis khaungraae).

Picture Credit: Lida Xing et al

When we Say Tiny we Mean Tiny!

The amber nodule containing the beautifully preserved skull, complete with the tongue, measures a little over three centimetres in length.  The skull, with its tiny jaws, lined with miniscule but pointed teeth, measures less than 1.5 cm long.  It is estimated that Oculudentavis had a total body length including tail of about 9 cm.  Palaeontologists have speculated that “microsaurs” – tiny dinosaurs co-existed with the giants, just as African spiny mice (genus Acomys), can be found today in the same habitats as the largest, terrestrial animals – elephants (Loxodonta).

Tantalising fossil footprints had been found that hinted at the possible existence of “microsaurs” or “tinysaurs” if you will – assuming of course that these trace fossils were not made by very young animals, with a lot of growing to do.

To read about the smallest dinosaur tracks: Smallest Dinosaur Tracks Known to Science Discovered.

A Life Reconstruction of the Tiny Oculudentavis khaungraae

Life reconstruction of Oculudentavis.

A life reconstruction of Oculudentavis.  It may have been small but the numerous teeth (23 teeth in the upper jaw alone), indicate that it was a predator probably hunting insects.

Picture Credit: Han Zhixin

A Possible Member of the Enantiornithes Clade

Where Oculudentavis sits on the Dinosauria family tree is uncertain.  Whilst the cranial material has provided the authors, which include researchers from the Chinese Academy of Sciences and the Natural History Museum of Los Angeles County, with a wealth of data, interpreting the taxonomy is somewhat troublesome.  If it is a member of the Maniraptora, this large clade includes dinosaurs as well as true birds (avians).  Just how closely related to the birds or whether it is a highly specialised dinosaur remains open to debate.  Oculudentavis could be an enantiornithine bird, an extinct lineage of avians that were the most common birds of the Cretaceous, or it might be more closely related to the dinosaur end of the Maniraptora spectrum.

It may be small, but the specimen does not represent a juvenile or young animal, the skull bones are sufficiently fused for scientists to confidently state that the tiny creature is an adult or at least a sub-adult.

Eye Tooth Bird

Oculudentavis demonstrates a suite of unusual anatomical characteristics.  The eyes for example, are located on the side of the head, helpful for providing all round vision but not capable of delivering stereoscopic vision to aid in the capture of small prey.  The orbits are huge, the eyes would have bulged out of the head somewhat and the bones that make up the sclerotic ring (the circle of bones in the orbit) are spoon shaped, which is a morphology previously only known in lizards.  These scleral ossicles form a cone, similar to the bones in the eyes of owls, so it can be deduced that just like owls, Oculudentavis had exceptional vision.  What is a little more surprising is that the opening at the centre of the ossicles is narrow and restricted.  This would have limited the amount of light coming into the eye, so unlike most owls this little Cretaceous creature probably operated in bright, sunny conditions – it was most likely diurnal.

A Computer Generated Image of the Skull of O. khaungraae

Oculudentavis khaungraae computer generated image of the skull.

Oculudentavis khaungraae computer generated image of the skull (left lateral view).  Note the huge size of the orbits, the small teeth in the jaws and the scale bar denoting the size of the specimen.

Picture Credit: Xing et al (Nature)

Such is the size and extent of the eye socket, that they extend over the jaws and some of the upper jaw teeth are located directly under the orbit.  It is this characteristic and those large eyes, that gives Oculudentavis its name, from the Latin for eye “oculus”, “dentes” teeth and “avis” for bird.  The species name honours Khaung Ra who donated the specimen to the Hupoge Amber Museum.

The Fossil Specimen (HPG-15-3) with Computer Generated Images and Accompanying Line Drawings

Oculudentavis images.

Photograph, computed tomography scans and interpretive drawings of the HPG-15-3 holotype of O. khaungraae.  Scale bar size equals 5 millimetres.

Picture Credit: Xing et al (Nature)

The photograph (above), shows the amber piece (a), a scan of the skull (b) with line drawing (c).  Images d, f and h represent other views of the scans, whilst images e, g and h represent the associated line drawings.  The amber specimen comes from the Angbamo site, close to the township of Tanai (Myitkyina district, Hukawng valley, Kachin province) in northern Myanmar.  The strata are believed to represent the Cenomanian stage of the Late Cretaceous, the fossil therefore is approximately 99 million years old.

Living on an Island?

The fossil discovery represents the smallest known dinosaur of the Mesozoic and it highlights the importance of amber as a means of permitting scientists to gain an insight into the ecology of a habitat thanks to the preservation of small animals and other material that would not necessarily have been preserved under other taphonomic processes.  Specimens preserved in amber are rapidly emerging as an exceptional way to study tiny vertebrates from the Late Cretaceous.

Miniaturisation in animals is commonly associated with living in isolated environments where resources are limited.  The tiny Oculudentavis lends weight to the idea that the amber deposits in northern Myanmar were produced in forests that existed on islands.  In addition, the size and morphology of this species suggest a previously unknown bauplan and a previously undetected ecology.

To read more articles about amazing fossil discoveries made in Burmese amber:

Ammonite shell discovery: Ammonite Shell Found in Amber Nodule.

Baby snake found in amber: Baby Prehistoric Snake – Xiaophis myanmarensis Preserved in Amber.

Ancient lice feeding on feathers: Lice Feeding on Feathers Entombed in Amber.

Tiny frogs preserved in Cretaceous amber: Tiny Frogs Trapped in Cretaceous Amber.

Post Publication Doubts?

Following publication, a number of academics have questioned the conclusions made by Xing et al with regards to this fossil representing a member of the Maniraptora.  It is certainly true that the validity of the interpretation of the fossil skull as maniraptoran has subsequently been challenged post publication (Wang Wei et al).  They comment that the shape of the skull is not unique to archosaurs, many lizards for example, show similar characteristics, the phylogenetic analysis is questioned, along with the apparent absence of an antorbital fenestra (an opening in the skull of all known archosaurs between the orbit and the naris).

It is suggested that the skull actually comes from a lizard and that the specimen is not from an archosaur at all.

The original publication noted that the spoon-shaped bones that make up the sclerotic ring were reminiscent of that seen in the eye sockets of lizards.  Scleral bones of this shape have never been found in a dinosaur or a bird, it is suggested that these bones support the idea that the fossil is that of a lizard and not a member of the Archosauria.

The roots of the tiny teeth do not seem to be located in sockets in the jawbone (thecodont dentition).  This was a peculiar feature remarked upon by a number of academics once this paper had been widely circulated.  Teeth located in sockets is a characteristic of toothed-archosaurs such as crocodilians and the dinosaurs.  Other types of tetrapod also show this tooth morphology, but in Oculudentavis the teeth are not in sockets but either fused to the jaw (acrodont dentition) or located within grooves that can be found along the length of the jaw bones (pleurodont dentition).

The number of teeth in the jaw far exceeds that known for any type of ancient bird.  The tooth line extending under the eye-socket (orbit), is also highly unusual.  Such anatomical traits are associated with the Squamata not with the Archosauria.

These arguments (along with others, such as the absence of feathers), have led some scientists to question the conclusions made in the original Nature publication.  Oculudentavis might not be a bird or a dinosaur, it might represent the preserved remains of a lizard.

10 03, 2020

Luchibang xingzhe – Long-legged Chinese Pterosaur Described

By | March 10th, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Luchibang xingzhe – Long-legged Chinese Pterosaur Described

A team of international scientists including Dr David Hone (Queen Mary University of London) and colleagues from the University of Wisconsin-Madison, the China University of Geosciences and the Institute of Vertebrate Palaeontology and Palaeoanthropology (Beijing), have published a paper describing a new species of long-legged pterosaur that once flew over the skies of what is now Inner Mongolia.  The new flying reptile has been named Luchibang xingzhe (pronounced Loo-chee-bang shing-hey).

The Nearly Complete Holotype Specimen of Luchibang xingzhe

The holotype specimen of Luchibang xingzhe (ELDM 1000).

The holotype specimen of Luchibang xingzhe.  Note scale bar equals 10 cm.  The skull is at the top, the elongated jaws are facing to the left.

Picture Credit: Palaeontologia Electronica

Described from a single, near complete, articulated specimen (ELDM 1000), this pterosaur has been assigned to the Istiodactylidae family, members of the Suborder Pterodactyloidea, known for their short-tails, long toe bones and very thin walls to their bones.  Istiodactylid pterosaurs were geographically widespread, fossils having been found in Lower Cretaceous sediments located in North America, the Isle of Wight (southern England) and northern China.

Although the animal was immature when it died, it already had a wingspan estimated at around two metres.  The fossil skeleton indicates that it was already much bigger than most other istiodactylids, suggesting a large wingspan (perhaps around five metres), as an adult.  Luchibang had proportionately long hindlimbs and these, plus the teeth, suggest that this flying reptile hunted fish, perhaps stalking them in the same way as a modern heron.  The pterosaur has been named in honour of Lü Junchang, (Chinese Academy of Geological Sciences), in recognition of his research work on Chinese members of the Pterosauria and from the Mandarin word for “heron”.

Robust and Elongated Hindlimbs

The fossil specimen is the most complete istiodactylid specimen described to date.  The completeness of the skeleton was one of the factors that led to allegations that the fossil had been faked.  Sadly, many fossils from China are “enhanced” to make them more valuable, however, after extensive analysis the specimen has been proved to be genuine, but this issue along with a debate with regards to phylogeny led to delays in publication.  It is to the credit of the research team that they persevered and that the scientific paper has now been published.  Intriguingly, the fossilised remains of two small fish (probably Lycoptera), are preserved in association with Luchibang.  One fish resides between the jaws (see photograph below), whilst the second is inside the rib cage and may represent the remains of this flying reptile’s last meal.  If the second fish fossil does represent gut contents, then this reinforces the idea that Luchibang was a piscivore (fish-eater).

A Close View of the Partial Skull and the Jaws of Luchibang xingzhe With Fish Remains in Association

A close view of the jaws of Luchibang showing the fish fossil.

A close view of the jaws of Luchibang showing the fish fossil in association.  The scale bar equals 5 cm and the black arrow points to the fossil fish.

Picture Credit: Palaeontologia Electronica

The scientific paper: “An unusual new genus of istiodactylid pterosaur from China based on a complete specimen” by David W. E. Hone, Adam J. Fitch, Feimin Ma and Xing Xu published in Palaeontologia Electronica.

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