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/Dinosaur and Prehistoric Animal News Stories

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

21 07, 2019

Scientists Conclude Dinosaurs Nested in Colonies

By | July 21st, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Mongolian Fossil Site Sheds Light on Theropod Nesting Behaviour

A team of international scientists writing in the academic journal “Geology”, have published a scientific paper that outlines strong evidence to indicate that at least some types of dinosaur nested communally and that the Dinosauria had a breeding season.   Communial nesting behaviour as seen in living theropods such as birds has been inferred in a variety of non-avian dinosaurs in the past.  Famous fossil sites such as “Egg Mountain” in Montana, a nesting site for the hadrosaurid Maiasaura (and one or two troodontids too), that has provided high concentrations of nests preserved in a single location suggest that some types of dinosaurs nested in colonies, but the difficulty lay in proving that all the nests were created and the eggs laid at roughly the same time.

A new fossil nesting site discovered in the Upper Cretaceous Javkhlant Formation of the eastern Gobi Desert (Mongolia), preserves at least fifteen egg clutches laid by a probable non-avian theropod and this site provides strong evidence for colonial nesting in the dinosauria.

A Field Photograph of One of the Dinosaur Nests

The most complete nest of dinosaur eggs preserved at the site.

The most complete clutch of discovered at the site, preserving 30 dinosaur eggs.

Picture Credit: Kohei Tanaka, (University of Tsukuba).

A Common Palaeosurface to the Fossil Finds

The researchers, which included scientists from the University of Calgary (Alberta, Canada), University of Tsukuba (Ibaraki Prefecture, Japan), Hokkaido University Museum (Hokkaido, Japan), and the Royal Tyrrell Museum (Alberta, Canada), studied fifteen egg clutches laid by a theropod dinosaur.  As all the eggs were very similar, (classified as the oofamily the Dendroolithidae), it is likely that all the nests were created by the same species of dinosaur.  Communial nesting behaviour has been inferred before, but unsually, at this fossil site, the mudstone and eggshell fragments that fell inside the eggs during, or soon after hatching, along with other sediments indicates the clutches were subsequently buried during a small flood event that deposited a thin red marker bed.  It is this thin marker bed and the consistency of sediment infill among the eggs that indicates that these clutches were laid and hatched during a single season.  In scientific terms, there is a common palaeosurface associated with the dinosaur nests and eggshell fragments.

A Natural Cross Section Through an Egg Showing the Palaeosurface

Identifying the palaeosurface - evidence of communial nesting.

A natural cross section through an egg that shows the palaeosurface on which the eggs were laid, and the mudstone layers that infill and overlay the eggs.

Picture Credit: Kohei Tanaka, (University of Tsukuba).

Strong Evidence to Suggest that Some Dinosaurs Nested in Colonies Just Like Some Birds

The discovery of clutches of dinosaur eggs believed to have been laid by the same species of dinosaur, at the same level within the palaeosurface indicates that this is probably the fossilised remains of a single breeding season event.

A Hypothetical View of the Theropod Nesting Site (Therizinosaurs Nesting)

Javkhlant nesting site - theropods colonial nesting.

Life reconstruction of the theropod nesting site at Javkhlant.  It is suggested that the eggs were laid by Therizinosaurs.

Picture Credit: Masato Hattori

Using Vegetation to Incubate Eggs

The researchers conclude that despite the absence of sedimentologic evidence indicative of nest structure, statistical analyses of egg characteristics and facies association suggests that the clutches were likely incubated in covered or buried nests.  Some types of ground-nesting bird bury their eggs and use vegetation to help incubate and regulate the nest temperature.  This behaviour is also found in that other extant branch of the Archosauria, the crocodilians.  Furthermore, based on the number of nests and eggs found, the hatching success of the colony is estimated at around 60%.  This hatching success is comparable to the hatching success found in crocodile nesting sites and amongst bird species that attend their nests and, very importantly, protect their nests from predators during the incubation period.

Therefore, it is likely that colonial nesting with parental attendance, widespread in living birds, likely evolved initially among non-brooding, non-avian dinosaurs to increase nesting success.  In essence, the sort of nesting behaviours observed in living archosaurs today (birds and crocodiles), is probaby a trait that evolved quite early on in the evolutionary history of the Archosauria.

Nest Guarding Behaviour in Dinosaurs

It has been inferred that dinosaurs protected their nests, based on evidence that some dinosaurs may have nested in groups.  The percentage hatching success calculated from this site, reinforces that inference that some theropods may have defended their nest and, in all likelihood, their newly hatched offspring as well.  The oofamily Dendroolithidae is associated with Therizinosaurs, although the eggs could have been laid by another type of dinosaur.  Therizinosaurs are theropods but importantly, they are thought to be herbivorous and so in the life reconstruction, the nest builders are depicted as Therizinosaurs breeding together as a form of protection against carnivorous theropods and other predators.

Everything Dinosaur acknowledges the assistance of a media release from the Royal Tyrrell Museum (Alberta) in the compilation of this article.

The scientific paper: “Exceptional preservation of a Late Cretaceous dinosaur nesting site from Mongolia reveals colonial nesting behavior in a non-avian theropod” by  Kohei Tanaka; Yoshitsugu Kobayashi; Darla K. Zelenitsky; François Therrien; Yuong-Nam Lee; Rinchen Barsbold; Katsuhiro Kubota; Hang-Jae Lee; Tsogtbaatar Chinzorig; Damdinsuren Idersaikhan published in the journal Geology.

17 07, 2019

The Etymology of Aquilarhinus and Mystery Fossil Material

By | July 17th, 2019|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|2 Comments

How Did Aquilarhinus Get its Name?  Mystery Fossils from Rattlesnake Mountain

Recently, team members at Everything Dinosaur wrote a blog article announcing the discovery of a primitive, “shovel-billed” hadrosaurid from the Big Bend National Park in south-western Texas.  We received an email asking us how this dinosaur got its name, here is a quick explanation of the etymology.

Aquilarhinus palimentus – What’s in a Name?

A life reconstruction of the head of Aquilarhinus.

An illustration of Aquilarhinus with a crest along its snout and its unusual beak that may have been used to shovel up soft plants.  Anatomical features related to the skull and jaws gave this dinosaur its name.

Picture Credit: ICRA Art

Aquilarhinus palimentus

The genus name is derived from the Latin “aquila” which means eagle and the from the Greek “rhinos” meaning nose.  The combination of these two words – “eagle nose” describes the shape of the rostrum of this newly described dinosaur.  It had a bony crest on its snout.  The species or trivial epithet is derived from a combination of Latin words – “pala” meaning shovel and “mentus” which is translated as chin.  The species name has therefore been erected to describe the assumed front portion of the lower jaw (predentary), that resembled a shovel.  It is thought that this broad-skulled, shovel-mouthed dinosaur fed by scooping up marsh plants.

Could the Scientists Have Found Another Hadrosaurid in the Big Bend National Park?

In addition to the fossil material found and ascribed to Aquilarhinus palimentus, researchers have also found additional fossils which are from a hadrosaurid, but they remain unsure whether these fragments of bone from the skull represent A. palimentus or another type of duck-billed dinosaur.  All the fossils ascribed to Aquilarhinus palimentus were found within four square metres, but these other bones were found just a short distance from the Aquilarhinus remains.  The researchers writing in the “Journal of Systematic Palaeontology”, state that this material might pertain to A. palimentus but none of these isolated bones exhibit diagnostic features that would allow for certain attribution.  For this reason, the research team describes this material separately and refrain from referring it to as A. palimentus, instead it is regarded as Hadrosauridae incertae sedis.  The term “incertae sedis” is from the Latin, it means “uncertain placement”, the palaeontologists are unsure which type of dinosaur the fossils represent.

Hadrosaurid Skull Elements from Rattlesnake Mountain (Big Bend National Park)

Hadrosauridae incertae sedis fossil material.

Hadrosaurid facial and cranial material from Rattlesnake Mountain (south-western Texas). Hadrosauridae incertae sedis.  The fossils from the skull are not diagnostic of a species, therefore the material is incertae sedis.

Picture Credit: Journal of Systematic Palaeontology

To read our previous blog post about the discovery of Aquilarhinus palimentusAn Unusual Shovel-billed Hadrosaurid

16 07, 2019

An unusual “shovel-billed” Hadrosaurid

By | July 16th, 2019|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Aquilarhinus palimentus from the Early Campanian of Texas

Researchers writing in the “Journal of Systematic Palaeontology” have announced the discovery of a new species of duck-billed dinosaur (hadrosaurid), although this dinosaur possessed a very peculiar “duck-bill”.  The dinosaur named Aquilarhinus palimentus, seems to have had a shovel-shaped beak, suggesting that it had a unique way of feeding.   The front of the jaws of duck-billed dinosaurs meet in a U-shape to support a cupped beak used for cropping vegetation.  Aquilarhinus was different, analysis of the front of the lower jaw (anterior portion of the dentary), indicate that the jaws of this plant-eater met in a strange W-shape, creating a wide, flattened shovel.

A Life Reconstruction the Newly Described Late Cretaceous Hadrosaurid Aquilarhinus palimentus

Life reconstruction of Aquilarhinus palimentus

Aquilarhinus palimentus life reconstruction.

Picture Credit: ICRA Art

From the Lower Shale Member of the Aguja Formation of Big Bend National Park (Texas)

In 1985, Tom Lehman, then a geology master’s student at the University of Texas was exploring Upper Cretaceous-aged outcrops in south-western Texas.  Whilst working on the western side of Rattlesnake Mountain, which is in the Big Bend National Park, he and his fellow field team members came across some badly weathered dinosaur fossil bones cemented together in an ironstone nodule.  For some years, the material remained in storage, a preliminary study of the skull material back in the 1990s identified a broad nasal crest and it was thought that this dinosaur was related to Gryposaurus.  This new research has identified a number of unique anatomical characteristics that merit these fossil bones being placed in their own genus.  Furthermore, Aquilarhinus was a more primitive hadrosaurid then Gryposaurus and as such, these fossils can perhaps help palaeontologists to understand how the huge variety of different duck-billed dinosaurs evolved.

Line Drawings Showing Views of the Skull and Jaws of Aquilarhinus palimentus

Views of the skull and jaws of Aquilarhinus.

Line drawing showing various views of the skull and jaws of Aquilarhinus palimentus.

Picture Credit: Journal of Systematic Palaeontology with additional annotation by Everything Dinosaur

The picture (above), shows line drawings that reconstruct the skull and jaws of A. palimentus.  The areas coloured brown indicate bones belonging to the holotype specimen.  Note (B), showing the skull viewed from the front, Everything Dinosaur has added an illustration of the symphyseal processes of the dentary indicating the unique “W-shaped” component to the lower jaw.  These bony struts are elongated and pushed upwards, causing the dentaries to meet with a “W-shaped” anterior profile.

The shales from which the fossil bearing nodules were recovered (Aguja Formation), date from the lower Campanian (about 80 million years old) and suggest that Aquilarhinus roamed a tidal marshland.  It may have been semi-aquatic using its “shovel-like” jaws to scoop vegetation out of the silt and mud.

The Lower Jaw of Aquilarhinus

The dentary of Aquilarhinus (lower jaw.

The lower jaw of Aquilarhinus palimentus (left lateral view).  Note, the white material is filler.

Picture Credit: Albert Prieto-Marquez

Much Smaller than Gryposaurus

Comparisons with the skull bones of Gryposaurus suggest that Aquilarhinus was probably about half the size of Gryposaurus, indicating an animal around five metres in length, although the size of Aquilarhinus is only conjecture.  More fossil material is required in order to make a more certain diagnosis.

Corresponding author of the scientific paper, Dr Albert Prieto-Márquez from the Institut Català de Paleontologia Miquel Crusafont (Spain) commented:

“This new animal is one of the more primitive hadrosaurids known and can therefore help us to understand how and why the ornamentation on their heads evolved, as well as where the group initially evolved and migrated from.  Its existence adds another piece of evidence to the growing hypothesis, still up in the air, that the group began in the south-eastern area of the United States.”

A Life Reconstruction of the Head of Aquilarhinus palimentus

A life reconstruction of the head of Aquilarhinus.

An illustration of Aquilarhinus with a crest along its snout and its unusual beak that may have been used to shovel up soft plants.

Picture Credit: ICRA Art

A Non-saurolophid Hadrosaurid

Phylogenetic analysis undertaken by the research team reveals Aquilarhinus to be superficially similar to dinosaurs like Kritosaurus and Gryposaurus but more likely to be more closely related to Latirhinus from the Late Campanian of Mexico.  As such, Aquilarhinus does not fit with the main group of duck-billed dinosaurs known as Saurolophidae.  It is more primitive than this group, suggesting there might have been a greater number of lineages than previously recognised that evolved before the great radiation that gave rise to the bewildering array of unadorned, solid and hollow-crested forms of duck-billed dinosaurs that thrived in northern latitudes during the Late Cretaceous.

Most saurolophids had bony head crests of many different shapes and sizes.  Aquilarhinus also sported a bony crest, albeit a simple one shaped like a humped nose.  The discovery of a solid crest outside the major radiation of hadrosaurids supports the hypothesis that all crests derived from a common ancestor that had a simple humped nose.

The scientific paper: “An unusual “shovel-billed” dinosaur with trophic specialisations from the Early Campanian of Trans-Pecos Texas, and the ancestral hadrosaurian crest” by Albert Prieto-Márquez, Jonathan R. Wagner and Thomas Lehman published in the Journal of Systematic Palaeontology.

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

13 07, 2019

Microraptor Ate Lizards

By | July 13th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

Stomach Contents Reveal New Species of Early Cretaceous Lizard

Scientists writing in the academic journal “Current Biology”, have described a new specimen of Microraptor (M. zhaoianus) from Liaoning Province (north-eastern China), that preserves the remains of a small lizard in its body cavity.  The remains of the lizard, inside what would have been the stomach of this little feathered dinosaur, are largely intact and articulated.  This indicates that the unfortunate lizard was swallowed head first, a feeding behaviour seen in extant carnivorous birds and many small reptiles.  The fossilised bones of the lizard represent a new species, it has been named Indrasaurus wangi.

Microraptor is now known to have fed on a variety of small vertebrates, supporting the interpretation that it was an opportunistic predator.

Microraptor About to Swallow the Unfortunate Indrasaurus

Microraptor feeds on Indrasaurus.

A life reconstruction of a Microraptor consuming the lizard Indrasaurus.  The position of the lizard’s remains inside the body cavity of Microraptor indicate that the lizard was swallowed head first.

Picture Credit: Doyle Trankina

Direct Evidence of Predator-Prey Interactions from the Jehol Biota

Direct evidence of diet and predator-prey relationships are extremely rare in the fossil record.  However, the exceptional preservation conditions associated with the Liaoning deposits have resulted in four examples of stomach contents in Microraptor specimens having been identified.  Microraptor is now known to have been a generalist, eating a variety of small vertebrates including  mammals, birds, fish, and with this new discovery, lizards.

Photograph of the Microraptor Specimen (STM5-32) Preserving the Lizard Indrasaurus wangi in the Body Cavity

Microraptor ate lizards.

The Microraptor fossil specimen (STM5-32) the white box indicates location of lizard remains.

Picture Credit: O’Connor et al (Current Biology)

The white lines in the photograph indicate the body cavity area of the Microraptor and show the location of the lizard fossil remains.  The genus name Indrasaurus comes from Hindu scriptures in which the deity Indra was swallowed by the dragon Vritra during their battle.  The species (trivial name), honours Yuan Wang, for his extensive work on the Jehol Biota and his assistance in helping to promote Chinese fossils through museum events and exhibitions.

An Interpretative Line Drawing Showing the Remains of Indrasaurus (I. wangi) in the Abdominal Cavity

The remains of the lizard inside the Microraptor.

A line drawing showing the remains of the lizard Indrasaurus wangi within the stomach cavity of a Microraptor (M. zhaoianus).

Picture Credit: O’Connor et al (Current Biology)

The interpretative drawing (above), shows the contents within the white box outlined in the specimen (STM5-32).  Analysis of the lizard’s bones indicate that it was probably a sub-adult when it met its doom.  Ironically, the Microraptor itself died shortly after eating the lizard, although this would probably have not been much comfort to Indrasaurus had it known this at the time.

Most scientists believe that Microraptor could fly, it is not known whether this little lizard was caught in a tree or captured on the ground after a terrestrial pursuit.  Perhaps Microraptor swooped down onto its prey from a lofty vantage point, a tactic common to many carnivorous birds today.  The probable troodontid Anchiornis from the older Late Jurassic Yanliao Biota is roughly the same size as Microraptor and fossils of Anchiornis reveal that this dinosaur ate lizards too.  However, comparison of the fossilised remains of prey suggests that dromaeosaurids such as Microraptor ingested prey that were fully digested, whereas, Anchiornis may have regurgitated undigested body parts, bringing up a pellet as demonstrated in many bird species alive today.  This feeding behaviour supports a closer relationship between true birds and Anchiornis and suggests that powered flight did not precipitate the evolution of pellet regurgitation (egestion), in these reptiles.

The scientific paper: “Microraptor with Ingested Lizard Suggests Non-specialized Digestive Function by Microraptor with Ingested Lizard Suggests Non-specialized Digestive Function” by Jingmai O’Connor, Xiaoting Zheng, Liping Dong, Yan Wang, Xiaomei Zhang and Zhonghe Zhou published in the journal “Current Biology”.

12 07, 2019

New Theropod Dinosaur from the Late Triassic of Switzerland

By | July 12th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Notatesseraeraptor frickensis – A Mixture of Coelophysid and Dilophosaurid Characteristics

A new European theropod dinosaur from the Late Triassic of Switzerland has been named and described this week.  This is big news, as very little is known about Late Triassic theropods that roamed Europe more than 200 million years ago, only a handful have been described to date, just four species.  The dinosaur has been named Notatesseraeraptor frickensis (No-tah-tess-er-ray-rap-tor frick-ensis), the genus name derives from the Latin “nota” meaning feature and “tesserae”, a Latin term to describe tiles used to create a mosaic, a reference to the mixture of anatomical features (dilophosaurid and coelophysoid) identified in the fossil bones. The trivial name honours the Swiss town of Frick, where the fossils were found.

The Body Plan, Known Fossil Material and a Skeletal Reconstruction of N. frickensis

Skeletal anatomy of Notatesseraeraptor frickensis

The silhouette shows the body plan of Notatesseraeraptor, known fossil material and pictures of the blocks that make up the holotype specimen.

Picture Credit: Nature: Ecology and Evolution

Lizard-eating Dinosaur

The partially articulated specimen was collected in 2006 from the famous Gruhalde clay pit in the town of Frick (Aargau Canton, northern Switzerland).  This clay pit has yielded large numbers of Plateosaurus fossils, although Notatesseraeraptor layer is located above the classic Plateosaurus bone beds.  The strata are from the middle part of the Gruhalde Member of the Klettgau Formation and represents Late Triassic (end-Norian) sediments.  The fossils associated with N. frickensis include a nearly complete skull, articulated forelimbs, vertebrae, hip bones and ribs.  The body cavity revealed the remains of a Clevosaurus, a lizard-like rhynchocephalian, distantly related to the extant Tuatara of New Zealand.  It is likely that the Clevosaurus remains represent this dinosaur’s last meal.

The Skull of Notatesseraeraptor frickensis

Notatesseraeraptor frickensis cranial material.

A view of the skull and upper jaw (Notatesseraeraptor frickensis).  Around 90% of the cranial fossil material was recovered.

A Carnivorous Dinosaur Reported from Switzerland

Around 90% of the skull material was excavated, giving Notatesseraeraptor one of the most complete carnivorous dinosaur skulls known from before the Late Jurassic.   Although, our knowledge of early theropod dinosaurs has improved greatly since the turn of the century, thanks mainly to fossil discoveries from North and South America, very little is known about the evolution and radiation of Late Triassic/Early Jurassic European theropods, their fossil record is notably sparse.  This new theropod species is the first meat-eating dinosaur to be described from Switzerland.

Notatesseraeraptor displays a mix of characteristics typically seen either in coelophysids or in dilophosaurids.  A phylogenetic analysis suggests that it is a member of the Neotheropoda clade with affinities to Dilophosaurus of the Early Jurassic and that Notatesseraeraptor is a basal member of that line of theropods that led to the Averostra (a group, of carnivorous dinosaurs that includes the Ceratosaurs).

The Late Triassic/Early Jurassic European Theropods

The nearly complete skull will help palaeontologists to better understand the evolutionary relationships between different types of Late Triassic/Early Jurassic theropod dinosaur.  The fossil specimen suggests a sub-adult with a length of between 2.6 to 3 metres, but this is speculation based on comparative analysis with dinosaurs such as Coelophysis and Tawa as the length of the tail of Notatesseraeraptor is not known.

A Life Reconstruction of a Typical Coelophysid Dinosaur (Coelophysis bauri)

Coelophysis model.

A life reconstruction of Coelophysis bauri.

Picture Credit: Everything Dinosaur

The three previously described species of Late Triassic European theropod are:

  • Liliensternus liliensterni – named in 1934 (von Huene) from the Middle and Late Norian of Germany
  • Procompsognathus triassicus – named in 1913 (Fraas) also from the Middle to Late Norian of Germany
  • Lophostropheus airelensis named in 1993 known from slightly younger rocks (Late Rhetian to Hettangian – Late Triassic to possibly Early Jurassic)

With the exception of a few scraps of bone associated with Liliensternus skull material and the recently described  Dracoraptor hanigani from south-Wales, no other skull material has been found relating to a neotheropod dinosaur from the Late Triassic/Early Jurassic  in the whole of Europe.

11 07, 2019

Terrestrial Bird-like Dinosaur Oldest Known from North America

By | July 11th, 2019|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Hesperornithoides miessleri – Helping to Map Out the Bird Family Tree

A joint team of British and American palaeontologists have announced the discovery of a new species of dinosaur that roamed the Late Jurassic of Wyoming.  The specimen consisting of both cranial and postcranial material lived around 150 million years ago and it has been tentatively placed within the troodontid branch of the Paraves part of the Theropoda.  It could help scientists to better understand the evolutionary relationships between feathered dinosaurs and true birds and it raises intriguing questions as to when powered flight evolved within the Dinosauria.

The little dinosaur, estimated to have measured less than a metre in length (single known specimen is either an adult or a sub-adult), has been named Hesperornithoides miessleri.

A Life Reconstruction of the Newly Described Dinosaur H. miessleri

Hesperornithoides miessleri - life reconstruction.

A life reconstruction of Hesperornithoides miessleri.

Picture Credit: Gabriel Ugueto

An Inhabitant of Wetlands

Writing in the academic journal PeerJ, the authors which include scientists from the University of Manchester, report the taphonomy of the fossil material suggests that this dinosaur was an inhabitant of wetland environments for at least a portion of its life history.  The fossil material was actually discovered back in 2001, whilst excavation work was being carried out on the fossil material associated with Supersaurus.  The fossil comes from Converse County (Wyoming), from strata making up the middle portion of the famous Morrison Formation.  The fossil-bearing strata from the “Jimbo Quarry” has been variously dated to the Oxfordian and Tithonian ages of the Jurassic.

Full Skeleton of Hesperornithoides miessleri

Known fossil material associated with Hesperornithoides miessleri.

Hesperornithoides fossil material “left” (A) and “right” (B) sides of the blocks after final preparation (B).  Scale bar = one cm.

Picture Credit: Levi Shinkle

A Resident of the Famous Morrison Formation

The Morrison Formation is famous for its vertebrate fossils, including many examples of dinosaurs, such as Allosaurus, Ceratosaurus, Diplodocus, Brontosaurus and Camarasaurus.  The carnivorous Hesperornithoides is the smallest dinosaur described to date from Wyoming.

Palaeontologist Bill Wahl  (Wyoming Dinosaur Centre), a co-author of the scientific paper, recalled how excited the field team were when they uncovered the block containing the partially articulated bones.

He stated:

“We were removing a ledge of overburden rock and found, unfortunately with a shovel, some tiny, delicate bones poking out.  We immediately stopped, collected as much of the bones as possible and spent the next few days frantically searching for more.  Only after some of the bones were cleaned did we realise that we had found something spectacular.”

In 2005, the fossil specimen was donated to the Big Horn Basin Foundation, a research and education-based not-for-profit organisation that was merged with the Wyoming Dinosaur Centre back in 2016.  This is how Hesperornithoides miessleri came into the Wyoming Dinosaur Centre’s fossil collection.  The fossil, now known as WYDICE-DML-001, was nicknamed “Lori”  and was examined by Dean Lomax (University of Manchester) and co-author of the study back in 2008, a successful crowdfunding campaign permitted extensive research to be undertaken.

Dean commented:

“I remember the first time I laid my eyes on this little dinosaur.  Even back then, I knew it was a significant discovery.  But, it wasn’t until 2015 when our dino team formed and we began to study ‘Lori’ in much more detail than ever before.”

Reconstructed Quarry Map of “Lori” (Hesperornithoides miessleri)

A quarry map of the fossil material asociated with Hesperornithoides.

Association of skeletal elements assembled from 3-D scans of specimen blocks prior to final mechanical preparation.

Picture Credit: PeerJ

Found on Private Land

The specimen was found on private land owned by the Miessler family.  The trivial name honours their help, support and assistance in bringing this little theropod to the attention of the scientific community.  The genus name is a combination of “Hesper”, referring to its discovery in the American West and “ornis” a nod to its very bird-like anatomy.

A Reconstruction of the Skeleton of Hesperornithoides miessleri

Hesperornithoides miessleri skeleton reconstruction.

Skeletal Reconstruction Hesperornithoides miessleri (scale bar = 25 cm).

Picture Credit: Scott Hartmann

A Key Conclusion of the Study

A key conclusion of the scientific paper relates to the origin of powered flight within the Dinosauria.  Hesperornithoides was very probably entirely terrestrial.  It could not fly, but it has a very bird-like body, suggesting that many features associated with an avian anatomy evolved in dinosaurs that lived out their lives on the ground.  It is the oldest dinosaur of this type, known from more than just teeth fossils from North America.  The terrestrial and flightless lifestyle is consistent with the base of Paraves, and with the base of paravian subclades, suggesting that avian flight evolved within the Avialae, most likely in the Late Jurassic or Early Cretaceous.

Lead author of the paper and PhD student at the University of Wisconsin-Madison, Scott Hartman stated:

“We wanted to expand the dataset used to test dinosaur-bird relationships, so we added hundreds of new species and tens of thousands of new characters.  We found that Lori is a primitive member of a group of dinosaurs that includes Troodon, but perhaps more importantly we discovered that the smaller details of the family tree of bird-like dinosaurs isn’t quite as resolved as some researchers would claim.”

Scott Hartman continued:

“For example, it only takes a few changes in the dataset for Hesperornithoides to be found as a closer relative of Velociraptor than of Troodon.  One robust finding we did come up with is that even as the interrelationships changed, the primitive members of all these groups were non-flying ground dwelling dinosaurs.  That means that some small relatives of Velociraptor such as Microraptor that looks like it could have glided evolved this separately from the modern bird family.”

Hesperornithoides Cranial Material

Fossil material and accompanying line drawings Hesperornithoides.

Hesperornithoides cranial material and interpretative line drawings.

Picture Credit: Levi Shinkle

The scientific paper: “A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight” by Hartman, S., Mortimer, M., Wahl, W. R., Lomax, D. R., Lippincott, J. and Lovelace, D. M and published in PeerJ.

Everything Dinosaur acknowledges the help of a media release from the University of Manchester in the compilation of this article.

5 07, 2019

Repeated Evolution of Herbivorous Crocodyliforms

By | July 5th, 2019|Animal News Stories, Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Fossil Teeth Suggests Lots of Different Types of Mesozoic Crocodiles

Researchers from the University of Utah have studied the teeth of extinct crocodyliforms and concluded that crocodiles occupied a large range of different ecological niches during the Age of Dinosaurs.  Furthermore, these geographically widespread and speciose reptiles adapted to a variety of diets and that herbivorous crocodyliforms evolved at least three times independently.  This suggests that plant-eating was a beneficial dietary strategy and not a unique occurrence.  Many of these crocodyliforms lived alongside omnivorous or herbivorous synapsids, illustrating an ecological partition that is not found today.

The Diets of Extinct Crocodyliforms were Diverse with Many Examples of Herbivory Identified

Extinct crocodyliforms had different shaped teeth.

Life reconstructions of extinct crocodyliforms. Differences in tooth shape are related to differences in diets.

Picture Credit: Jorge Gonzalez

Writing in the academic paper “Current Biology”, the researchers Keegan Melstrom and Randall Irmis at the Natural History Museum of Utah at the University of Utah, discovered that multiple ancient groups of crocodyliforms (the group including living and extinct relatives of crocodiles and alligators), were not all carnivorous.  Research has been conducted before on the various potential dietary niches of ancient crocodiles, but this new study proposes that vegetarianism arose at least three times within this group.

Commenting on the significance of this new study, doctoral student Keegan Melstrom stated:

“The most interesting thing we discovered was how frequently it seems extinct crocodyliforms ate plants.  Our study indicates that complexly shaped teeth, which we infer to indicate herbivory, appear in the extinct relatives of crocodiles at least three times and maybe as many as six.”

Teeth Variation within Crocodyliforms (Extinct and Extant)

Heterodonty in Crocodyliforms.

False colour 3-D images showing the range in shape of crocodyliform teeth.  Carnivores (left), such as the living Caiman, have simple teeth, whereas herbivores (right) have much more complex teeth.

Picture Credit: Keegan Melstrom (The Natural History Museum of Utah)

The Tip of the Crocodyliform Iceberg

The twenty plus species of crocodylians alive today possess a similar general body shape and ecology.  They are mainly generalist hypercarnivores and semi-aquatic, confined to lower latitudes.  Although, consuming fruit and vegetable matter has been observed in several extant species.  In 2013, Everything Dinosaur wrote an article about fruit consumption (frugivory), in crocodiles.

To read the article: New Study Suggests a Number of Different Types of Crocodylian Consume Fruit.

The crocodiles alive today, all have similar, simple conical teeth but the fossil record shows that extinct crocodyliforms were much more diverse.  Today’s crocodiles are just the remnants from a once much richer and more specious group of reptiles, consider the living crocodylians as the “tip of the crocodyliform iceberg”.

Living Crocodiles are Generalist Ambush Predators (Hypercarnivores)

Saltwater crocodile (Estuarine crocodile).

A Saltwater crocodile (Crocodylus porosus), the largest living reptile which is an apex predator (hypercarnivore).

The researchers identified different teeth morphologies (heterodonty) and this suggests that in the past crocodile-like creatures had a variety of diets.

Melstrom added:

“Carnivores possess simple teeth whereas herbivores have much more complex teeth.  Omnivores, organisms that eat both plant and animal material, fall somewhere in between.  Part of my earlier research showed that this pattern holds in living reptiles that have teeth, such as crocodylians and lizards.  So, these results told us that the basic pattern between diet and teeth is found in both mammals and reptiles, despite very different tooth shapes, and is applicable to extinct reptiles.”

Keegan Melstrom (The Natural History Museum of Utah) with Some of the Casts Used in the Study

Examing three-dimensional prints of fossil jaws.

Keegan Melstrom, the study’s lead author, with the fossil jaw of Brachychampsa and 3-D prints of other extinct crocodyliforms (blue).

Picture Credit: The Natural History Museum of Utah

Comparing Tooth Complexity – Extinct versus Extant

To deduce what long dead crocodyliforms most likely consumed, Melstrom with the assistance of his graduate advisor ( Randall B. Irmis), compared the tooth complexity of extinct crocodyliforms to those of living animals using a research methodology originally designed to study mammalian heterodonty.  In total, 146 teeth from 16 different species of extinct crocodyliforms were incorporated into the study.

Using a combination of quantitative dental measurements and an assessment morphological features, the scientists reconstructed the diets of those extinct animals.  The results indicate that these animals had a wider range of dental complexities and presumed dietary ecologies than had been appreciated previously.  Quantitative analyses also revealed that some species with complex dentition were likely to be herbivorous.

The researchers conclude that plant-eating crocodyliforms appeared early in the group, perhaps shortly after the end-Triassic mass extinction event and herbivory persisted until the end of the Age of Dinosaurs.  The analysis suggests that herbivory arose independently a minimum of three times, and possibly six times, in Mesozoic crocodyliforms.

Melstrom stated:

“Our work demonstrates that extinct crocodyliforms had an incredibly varied diet.  Some were similar to living crocodylians and were primarily carnivorous, others were omnivores and still others likely specialised in eating plants.  The herbivores lived on different continents at different times, some alongside mammals and mammal relatives, and others did not.  This suggests that herbivorous crocodyliforms were successful in a variety of environments!”

As many of these herbivorous crocodyliforms co-existed with plant-eating synapsids including Mammaliaformes, some of which were the ancestors of today’s mammals, this was an ecological partition that is no longer found on our planet.

The scientific paper: “Repeated Evolution of Herbivorous Crocodyliforms during the Age of Dinosaurs” by Keegan M. Melstrom and Randall B. Irmis published in Current Biology.

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

28 06, 2019

The First Dinosaur from the Caiuá Group (Brazil)

By | June 28th, 2019|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Vespersaurus paranaensis – A Desert Dwelling Dinosaur

Roaming the Late Cretaceous of Brazil some 90 to 85 million years ago, was a little, fast-running, carnivorous dinosaur with a unique way of getting about.  The dinosaur has been named Vespersaurus paranaensis and at an estimated length of just over a metre (maximum length 1.6 metres), this was no giant, but its discovery will help scientists to work out the taxonomic relationships amongst an obscure group of theropods known mainly from Gondwana and provide new insight into theropod locomotion.

Writing in the academic journal “Scientific Reports”, the researchers suggest that Vespersaurus supported its weight on just one digit (metatarsal III and toe III), it may have been essentially monodactyl i.e. it had one main, central weight-bearing toe.  The other toes associated with support and weight bearing in the Theropoda (digits II and IV), were very much smaller and may even have been held off the ground.

A Life Reconstruction of the Newly Described Brazilian Theropod Vespersaurus paranaensis

Vespersaurus life reconstruction.

A life reconstruction of the Brazilian dinosaur Vespersaurus.

Picture Credit: Rodolfo Nogueira

Affinities with the Abelisauroidea

Analysis of the fossil material, which includes vertebrae, elements from the pelvis and limbs along with fragmentary skull bones suggests that this little dinosaur is a member of the Abelisauroidea, specifically the Noasaurinae, an enigmatic subfamily collectively known from sparse fossil material mostly from southern latitudes.  For example, Vespersaurus has the reduced forelimbs which are characteristic of the abelisaurids and it is hoped that these fossils will help palaeontologists to better understand the phylogeny of these Late Cretaceous predators.  Although only about 40% of the skeleton is known, these fossils represent one of the best examples of a member of the Noasauridae family found to date and the most complete dinosaur specimen from the whole of the Bauru Sub-basin.  It is also the first dinosaur to be described from rocks that constitute part of this basin, the Caiuá Group.

Frontal (Skull Bone) and Views of an Isolated Tooth (Vespersaurus paranaensis)

A skull bone and an isolated tooth (Vespersaurus paranaensis).

Cranial and dental remains of Vespersaurus paranaensis, an isolated frontal and an isolated broken tooth.

Picture Credit: Scientific Reports (Langer et al)

A Late Cretaceous Desert Environment

The majority of the strata making up the Caiuá Group represent sandstones that were deposited by the action of wind (aeolian deposits).  During the Late Cretaceous, this region of Gondwana was an extensive desert.  The fossil record is particularly sparse with only a handful of animals recorded from what probably would have been oases.  Arguably, the most famous fossils from this part of the world represent a pterosaur monodominant bonebed (Caiuajara dobruskii).  Other than Caiuajara and this new dinosaur, the only other vertebrate fossils known from this area represent a lizard and a turtle.

Pectoral Elements and Limb Bones (V. paranaensis)

Front limb bones and elements from the pectoral girdle (Vespersaurus paranaensis).

Pectoral girdle and limb elements of Vespersaurus paranaensis.

Picture Credit: Scientific Reports (Langer et al)

To read about Caiuajara: New Species of Flying Reptile Identified from Pterosaur Graveyard

Strange Footprints

Examination of the foot bones and toes suggests that this dinosaur supported its weight on just a single, central digit.  Such an anatomical adaptation (a monodactyl stance), has not been recorded in the Archosauria before, but such a form of locomotion had been inferred by palaeontologists as numerous footprints indicating an enlarged weight-bearing toe in a theropod dinosaur have been found in rocks of the same age as the sediments that yielded the fossils of Vespersaurus.

A Close Up of the Foot Showing the Weight-bearing Toe

The foot of Vespersaurus

A close-up view of the foot of Vespersaurus showing the weight-bearing central toe.  Footprints suggesting a monodactyl stance have been found in the same stratigraphic unit that yielded the new dinosaur.

Video image credit: Universidade de Sáo Paulo et al

Helping to Classify the Noasaurinae

The Noasaurinae are a branch of the Abelisauroidea consisting of small, predatory theropods known from Upper Cretaceous strata mostly associated with Gondwana (southern latitudes).  Perhaps the best known noasaurid is Masiakasaurus knopfleri, from the latest Cretaceous (Maastrichtian) of Madagascar, but two other taxa from Argentina described from relatively fragmentary fossil material have been assigned to the Noasaurinae (Noasaurus leali and Velocisaurus unicus).  Other dinosaurs from outside South America have also been tentatively assigned such as an as yet, unnamed specimen from India, Deltadromeus agilis from Morocco and Genusaurus sisteronis from France.  It is hoped that this more complete fossil specimen will permit palaeontologists to better understand taxonomic relationships within the Noasaurinae and their wider placement within the Abelisauroidea.

Building a Family Tree of the Abelisauroidea

Classifying Vespersaurus.

Vespersaurus is assigned to the Noasaurinae, a sub-family of the Abelisauroidea clade of theropods.  The suggested position of Vespersaurus is shown by the red dinosaur silhouette.

Picture Credit: Scientific Reports (Langer et al)

Etymology of Vespersaurus

The generic name derives from the words “vesper” (Latin for evening/west) and “sauros” (Greek for lizard/saurian), in reference to the name of the town Cruzeiro do Oeste (Western Cross), where the fossils were found.  The specific epithet refers to the Paraná state, the authors report that V. paranaensis represents the first non-avian dinosaur from that area of Brazil.

The scientific paper: “A new desert-dwelling dinosaur (Theropoda, Noasaurinae) from the Cretaceous of south Brazil” by Max Cardoso Langer, Neurides de Oliveira Martins, Paulo César Manzig, Gabriel de Souza Ferreira, Júlio César de Almeida Marsola, Edison Fortes, Rosana Lima, Lucas Cesar Frediani Sant’ana, Luciano da Silva Vidal, Rosangela Honório da Silva Lorençato and Martín Daniel Ezcurra published in the journal Scientific Reports.

21 06, 2019

A New Species of Australian Prehistoric Crocodile is Announced

By | June 21st, 2019|Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

Isisfordia molnari – A New Species of Australian Crocodile from the Cretaceous

Researchers from the University of New England (New South Wales), Queensland University and the Australian Opal Centre have described a new species of prehistoric crocodile.  The Cretaceous-aged croc has been named Isisfordia molnari, it is the second species described within the Isisfordia genus, both are known from Australia, although I. duncani, which was named in 2006, heralds from the Winton Formation of Queensland, whilst the new species I. molnari, comes from the geologically younger Griman Creek Formation of New South Wales.

A Life Reconstruction of the Newly Described Prehistoric Crocodile Isisfordia molnari

Isisfordia life reconstruction.

Isisfordia molnari life reconstruction.  A wading Sauropod has nothing to fear from I. molnari.

Picture Credit: José Vitor Silva

Honouring Ralph Molnar

The trivial name honours vertebrate palaeontologist Ralph Molnar, in recognition of his contribution to the research on crocodylomorphs from Gondwana.  Molnar was one of the researchers responsible for the naming of Isisfordia duncani back in 2006.  The new species has been erected based on a partial braincase and a fragment of jawbone (maxilla).  Both fossils have been opalised and come from the Lightning Ridge area, but their exact provenance remains uncertain.  The fossil jaw fragment had previously been designated as the holotype of Crocodylus (Bottosaurus) selaslophensis, but has, following a review, been assigned to this new species.  This piece of jawbone complete with six teeth in situ had been donated to the Australian Museum in 1914.  The partial braincase is probably a much more recent find, it was purchased by the Australian Museum in the early part of this century.

Photographs and Line Drawings of the Braincase of Isisfordia molnari

Isisfordia molnari braincase.

Photographs and line drawings of the braincase of Isisfordia molnari.  (A, B) dorsal, (C, D) ventral, (E, F) caudal, (G, H) rostral, (I, J) right lateral and (K, L) left lateral views.

Picture Credit: PeerJ

The Fragment of Upper Jawbone Assigned to the Newly Erected Species (I. molnari)

Jaw fragment (Isisfordia molnari).

A fragment of jawbone now assigned to Isisfordia molnari.  Arrows indicate rostral end ((A) medial, (B) lateral, (C) palatal views).

Picture Credit: PeerJ

The scientific paper: “Isisfordia molnari sp. nov., a new basal eusuchian from the mid-Cretaceous of Lightning Ridge, Australia” by Lachlan J. Hart, Phil R. Bell, Elizabeth T. Smith and Steven W. Salisbury published in PeerJ.

17 06, 2019

Dinosaur “Fossil Wall” Discovered in South-western China

By | June 17th, 2019|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Treasure Trove of Dinosaur Fossils Discovered

Reports have been circulating from a number of Chinese media outlets concerning the discovery of an extensive fossil bed containing the remains of numerous dinosaurs in southwest China’s Chongqing Municipality.  The fossil site has been known about for several years but there have been a number of reports this week circulating, hinting at the extent of the fossil discovery and indeed, suggesting that it is very likely that as a result of excavation work, new species of dinosaur will be named and described.

An Extensive Dinosaur Bonebed

Mapping and excavating a fossil site.

Excavating an extensive fossil deposit.

Picture Credit: VCG

The photograph (above), shows a Chinese field team member working on the “wall of dinosaur fossils”.  The site of the fossil find is described as a location close to Laojun village, Pu’an town, in Yunyang county.

New Dinosaur Species

The press reports state that scientists have identified different types of dinosaurs including theropods and basal ornithopods.  The disarticulated remains represent a bone accumulation and the strata is reported to be around 174 million years old (Aalenian faunal stage of the Middle Jurassic).  Commentators have described these fossil beds as very significant and likely to lead to the naming of new dinosaur species.

An Illustration of a Typical Basal Ornithopod

A typical ornithopod.

A typical example of a basal ornithopod.

Picture Credit: Everything Dinosaur

Four Thousand Individual Fossil Pieces

The mixed fossil assemblage has already provided researchers with around 4,000 pieces of dinosaur bone to study, since the site was first explored and mapped in 2017.

A spokesperson from Everything Dinosaur commented:

“The site has been described as exceeding 150 metres in length with at least 17 distinct assemblages of fossils within it.  Not much is known about the dinosaur biota from the earliest stages of the Middle Jurassic.  Once all the bones have been removed, prepared and studied it is very likely that several new species of dinosaur will be announced.  These dinosaurs will help palaeontologists to map the radiation and dispersal of several key groups of dinosaurs that were to dominate terrestrial ecosystems for the remainder of the Jurassic.”

The Famous Dinosaur Monument (Utah)

The famous Dinosaur Monument (Utah).

The Dinosaur Monument (Utah).

The extensive fossil material could become China’s equivalent of America’s Dinosaur Monument in Utah.  The Dinosaur Monument represents a congregation of dinosaur fossils that accumulated in a river deposit.  Whilst similarities can be drawn between the two sites, the Chongqing Municipality deposits are approximately 25 million years older.

Perhaps, this could be China’s second “Great Wall”.

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