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21 11, 2022

New Dromaeosaurid Species with Preserved Intestinal Tract

By | November 21st, 2022|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A new species of Chinese dromaeosaurid dinosaur has been described based on superbly preserved remains found in Inner Mongolia. The new dromaeosaurid species has been named Daurlong wangi and a phylogenetic assessment suggests that this dinosaur was closely related to Tianyuraptor and Zhenyuanlong.

Daurlong wangi holotype fossil
Daurlong wangi holotype fossil material, a new dromaeosaurid from the Lower Cretaceous Jehol Biota of Inner Mongolia, China. The whole specimen (a), close-up view of the skull (b) scale bar = 2 cm, with (c) detail of the orbit scale bar = 1 cm. Traces of feathers associated with trunk (d) and (e) the preserved remains of a frog in association with the dromaeosaurid. Picture credit: Wang et al.

Daurlong wangi

Described by the scientists, which include researchers from Chinese Academy of Geological Sciences and the Inner Mongolia Museum of Natural History, as a mid-sized dromaeosaurid, Daurlong is estimated to have been around 1.5 metres long. The nearly complete specimen comes from Lower Cretaceous exposures of the Longjiang Formation in the Morin Dawa Daur Autonomous Banner (Inner Mongolia). The fossilised remains were excavated from Pigeon Hill, apt as this feathered dinosaur was related to modern birds (Aves). Both birds and the Dromaeosauridae are members of the Eumaniraptora clade.

New Dromaeosaurid Species

The binomial scientific name for this new dromaeosaurid is derived from the indigenous Daur Nation and from the Chinese word for dragon. The species name honours the director of the Inner Mongolia Museum of Natural History, Mr Wang Junyou.

Daurlong wangi fossils and skeletal drawings
The Daurlong wangi holotype – specimen number IMMNH-PV00731. Skull (a, b), left scapula (c), sternum and left hand (d, e), right forelimb (f). Reconstruction in (g) by M. Auditore (CC-BY 4.0). Note scale bar in skeletal reconstruction = 10 cm. Picture credit: Wang et al.

Finding a Frog

Some evidence of plumage is preserved along the top of the back of the skull, around the trunk and along the edges of the tail. The scientists writing in the academic journal “Scientific Reports” found no evidence of preserved melanosomes in association with the feather filaments.

A bluish layer located towards the back of the rib cage has been putatively described as remnants of the intestines. Such a soft tissue discovery would be exceptionally rare within the Dinosauria, and could help inform palaeontologists over the origins and evolution of the digestive tract of birds and other closely related genera.

The fossilised remains of a small frog were found in the same slab as the Daurlong specimen. Everything Dinosaur is not aware of any gut contents indicating that this small, meat-eater ate frogs, but it is very likely that Daurlong would have consumed amphibians such as frogs as well as lizards and small mammals.

Zhenyuanlong suni scale drawing.
A scale drawing of Zhenyuanlong suni. The newly described dromaeosaurid Daurlong wangi is thought to have been closely related to Zhenyuanlong. Picture credit: Everything Dinosaur.

The Beasts of the Mesozoic range of articulated prehistoric animal figures contains several examples of Cretaceous dromaeosaurids.

To view the Beasts of the Mesozoic range of models: Beasts of the Mesozoic Model Range.

The scientific paper: “Intestinal preservation in a birdlike dinosaur supports conservatism in digestive canal evolution among theropods” by Xuri Wang, Andrea Cau, Bin Guo, Feimin Ma, Gele Qing and Yichuan Liu published in Scientific Reports.

2 11, 2022

Marine Reptile Casts Copies of Priceless Fossil Thought Lost

By | November 2nd, 2022|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A world’s first complete fossil skeleton of a prehistoric reptile studied by scientists that was thought lost forever, has been re-discovered as researchers uncovered marine reptile casts. These casts, although replica copies of the actual fossils, can still provide palaeontologists with valuable information.

Original illustration and pictures of the marine reptile casts.
Original scientific illustration by William Clift (top) and the two newly discovered marine reptile casts. Picture credit: The Royal Society.

“Proteosaurus” Resurfaces

The fossilised remains of an ichthyosaur that was probably excavated by Mary Anning and named “Proteosaurus”, was destroyed in a German bombing raid in World War II. It had been assumed that this historically significant fossil had been lost to science, however, palaeontologists have identified two plaster casts held in collections outside of the UK, which reveal important new data. The casts were discovered by Dr Dean Lomax, a palaeontologist and Visiting Scientist at the University of Manchester, and Professor Judy Massare, from the State University of New York, Brockport, USA.

Dr Lomax in collaboration with renowned palaeoartist Bob Nicholls recently produced a book which looks at the astonishing direct evidence indicating the lives and behaviours of long-extinct animals that can be found in the fossil record. The book entitled “Locked in Time” can be found here (search on the website for author Dean Lomax): Columbia University Press.

Found in 1818

The ichthyosaur fossil was discovered in 1818 at Lyme Regis, Dorset, and almost certainly found by the famous pioneering palaeontologist Mary Anning. Named “Proteosaurus” the specimen was acquired by a prolific collector, Lt-Col. Thomas James Birch, who sold it to the Royal College of Surgeons, London in 1820, to raise funds for Mary Anning and her family who were struggling to pay their rent.

The fossil discovery came at a time when academics were beginning to scientifically study prehistoric animal remains, the sciences of geology and palaeontology were developing. Ichthyosaur fossils had been found earlier, but there was disagreement as to what the specimens represented. Each new fossil find was adding important information to the debate and the 1818 specimen was the most complete ichthyosaur skeleton found to date. It was examined by Sir Everard Home, a highly respected British surgeon, who published his findings in the journal of The Royal Society in 1819.

Unfortunately, the fossil was completely destroyed by a German air raid in May 1941, when the Royal College of Surgeons in London was bombed.

Marine reptile casts - "Proteosaurus" cast from the Natural History Museum (Berlin, Germany)
Dr Dean Lomax with the cast from the Natural History Museum (Berlin). Picture credit: Dean Lomax/University of Manchester.

An Important Role in Establishing Palaeontology as a Scientific Discipline

Dr Dean Lomax commented:

“When research on this fossil was published, it was still more than twenty years before the word “dinosaur” would be invented. This and other early ichthyosaur finds sparked a major interest in collecting more of these curious, enigmatic creatures. The discoveries and research on ichthyosaurs played an important role in establishing palaeontology as a scientific discipline.”

Dr Lomax and Professor Massare have collaborated on numerous projects and have made several important discoveries whilst studying historic fossil collections. For example, in 2015, their research led to the naming of Ichthyosaurus anningae, the first, new Ichthyosaurus species to be named in nearly 130 years.

To read more about I. anningae: New Ichthyosaurus Species Named Honouring Mary Anning.

Discovery at the Peabody Museum

In 2016, whilst examining the marine reptile collection housed at the Peabody Museum (Yale University), Massare and Lomax found an extremely old replica cast of an ichthyosaur, which was subsequently identified as the first-known cast of the fossil studied by Sir Everard Home. Up until this point, there was no record of any casts of this significant ichthyosaur fossil.

The Museum Assistant in vertebrate palaeontology at the Peabody Museum, Daniel Brinkman explained:

“Peabody curatorial staff assumed that the specimen was a real ichthyosaur fossil and not a plaster cast painted to look like the original fossil from which it was moulded.”

The Yale University cast was purchased by Yale Professor Charles Schuchert, as part of a substantial collection of fossils from the estate of Frederick A. Braun, a professional fossil dealer, however, very little else is known about the cast. It is not known when Braun acquired it, or who made the cast.

The Berlin Discovery

In 2019, Dean Lomax visited the Natural History Museum in Berlin (Germany) to study their fossil collection and was surprised to find a second cast of the 1818 ichthyosaur. This replica was in much better condition than the Yale cast.

The scientific head of collections at the Natural History Museum (Berlin), Dr Daniela Schwarz commented:

“When Dr Lomax visited our collections, he kept asking me for information about this cast and I couldn’t help him very much because of missing records and labelling of the specimen. So, when I learned about the outcome of his detective work and that this important specimen’s cast now rested in our collections for more than a century, I was really stunned! This discovery once more demonstrates the necessity to carefully preserve also undetermined and casted material in a natural history collection for centuries, because in the end, there will always be someone who discovers its scientific value!”

Marine reptile casts - Dean Lomax holds the Berlin cast.
Dr Dean Lomax holds the precious Berlin fossil cast. Picture credit: Dean Lomax/University of Manchester.

Studying the Ichthyosaur Fossil Replicas

Studies of both casts have shown that they were made at two different times. The Yale cast might even be a very old cast made when the ichthyosaur was still in the possession of Lt-Col. Thomas James Birch.

Professor Massare said:

“In Home’s 1819 article, he illustrated the original skeleton. This drawing by William Clift was the only visual evidence we had of the ichthyosaur. Now, having two casts, we can verify the reliability of the original illustration by comparison with the casts. We have identified a couple of bones that Home missed, and found a few discrepancies between the drawing and the casts.”

This new study has been published today in the journal, Royal Society Open Science, one of the journals of The Royal Society, which ironically published the original paper on the discovery of the ichthyosaur fossil back in 1819.

Explaining the decision to publish in Royal Society Open Science, Dr Lomax stated:

“When we discovered the casts, we felt compelled to submit our research to The Royal Society, especially because they had played a major role in publishing the first accounts of ichthyosaurs in the scientific literature over two hundred years ago.”

Professor Massare added:

“We hope that our discovery of these two casts might encourage curators and researchers to take a closer look at old casts in museum collections.”

Everything Dinosaur acknowledges the assistance of a media release from the University of Manchester.

The scientific paper: “Rediscovery of two casts of the historically important ‘Proteo-saurus’, the first complete ichthyosaur skeleton” by D. R. Lomax and J. A. Massare published in Royal Society Open Science.

13 10, 2022

Dinosaur Mummies an Alternate Fossilisation Pathway

By | October 13th, 2022|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Research into a beautifully preserved Edmontosaurus fossil suggests that dinosaur mummies might be more common than previously thought. The Edmontosaurus specimen found by Tyler Lyson when exploring Slope County (North Dakota) and Hell Creek Formation exposures contained therein is providing palaeontologists with an insight into the fossilisation process that might produce a “dinosaur mummy”.

A mummified dinosaur was thought to require two mutually exclusive taphonomic processes in order to form. Firstly, to have the carcase exposed on the surface for a considerable portion of time to permit the remains to dry out and become desiccated. Secondly, rapid burial and deposition to preserve what remains of the corpse.

The taphonomy of the Edmontosaurus specimen (NDGS 2000), suggests that there may be other circumstances the lead to the mummified remains of dinosaurs.

Edmontosaurus "Dakota" Skin Preservation
Distribution and current state of preparation of the preserved skin on the Edmontosaurus specimen (NDGS 2000). Life reconstruction by Natee Puttapipat. Black areas in the diagram indicate portions of the skeleton apparently absent from the specimen, light grey areas indicate regions where the skeleton is preserved but no skin is currently preserved, red areas indicate regions where skin is present and is still undergoing preparation. The yellow shading indicate areas where the skin is fully prepared and were examined in this study. Picture credit: Drumheller et al (PLoS One).

Dinosaur Mummies – Hooves and Fingers (E. annectens)

A team of scientists, including researchers from University of Tennessee–Knoxville, Knoxville, Tennessee and the North Dakota Geological Survey team, writing in the academic journal PLoS One propose a new explanation for how such fossil specimens might form. Large areas of desiccated and seemingly deflated skin have been preserved on the limbs and tail. Such is the degree of preservation of the front limb, (manus) that palaeontologists have discovered that Edmontosaurus (E. annectens) had a hoof-like nail on the third digit.

This discovery led to a substantial revision of Edmontosaurus limb anatomy in prehistoric animal replicas, as epitomised by the recently introduced CollectA Deluxe 1:40 scale Edmontosaurus.

CollectA Deluxe 1:40 scale Edmontosaurus dinosaur model
The new for 2022 CollectA Deluxe 1:40 scale Edmontosaurus dinosaur model. CollectA had wanted to introduce a replica of this iconic Late Cretaceous hadrosaur for some time. Many of the details such as the hoof-like third digit on the hand and the enlarged scales on the neck replicate what the scientists have discovered by studying the Edmontosaurus dinosaur mummy known as Dakota.

To read a blog article that contains a video review of the Edmontosaurus and explains more about the “dinosaur mummy” research: Everything Dinosaur Reviews the CollectA Deluxe Edmontosaurus Dinosaur Model.

Evidence of Scavenging

The research team identified bite marks from carnivores upon the dinosaur’s skin. These are the first examples of unhealed carnivore damage on fossil dinosaur skin, and furthermore, this is evidence that the dinosaur carcass was not protected from scavengers by being rapidly buried, yet it became a mummy nonetheless.

Many of the marks suggest bites from the conical teeth of crocodyliforms, although pathology associated with the tail is more difficult to interpret. The researchers suggest that some of the “V-shaped” patterns identified suggest that flexible, clawed digits rather than more rigidly fixed teeth, may have been responsible for these injuries. Perhaps these marks were caused by feeding deinonychosaurs (Dakotaraptor steini) or perhaps a juvenile T. rex.

Examining the Decomposition of Carcases

If the carcase was scavenged, then it was not buried rapidly and one of the supposed pre-requisites for “dinosaur mummification” did not occur with this fossil specimen. Instead, the researchers propose an alternative route for the creation of such remarkable fossils, a theory that has been influenced by what is observed in the world today. When scavengers feed on a carcase, they rip open the body and feed on the internal organs. Punctures made in the body allow fluids and gases formed by decomposition to escape, thus permitting the skin to dry out, forming a desiccated, dried out husk.

Evidence of desiccation of the Edmontosaurus fossil
Evidence of desiccation in the preserved remains of the Edmontosaurus (specimen number NDGS 2000). Note all scale bars equal 10 cm. Life reconstruction by Natee Puttapipat. Picture credit: Drumheller et al (PLoS One).

Dinosaur Skin More Commonly Preserved

The research team postulate that if the more durable soft tissues can persist some months prior to burial to permit desiccation to occur, then dinosaur skin fossils, although rare, are possibly, more commonly preserved than expected.

Edmontosaurus "Dakota" right manus preservation pathway
Cross sectional views through the right manus of the Edmontosaurus fossil (NDGS 2000). NDGS 2000 reconstruction in right lateral view (A). Right manus in dorsal view indicating the positions of the three cross sectional views (B). CT image along line x to x’ (C). CT image along line y to y’ (D). CT image along line z to z’ (E). In (C), (D), and (E), slice numbers from the original CT data are provided above each image. Paleoart in (A) by Natee Puttapipat. Scale bars equal 1 cm. Picture credit: Drumheller et al (PLoS One).

A New Theory on How “Dinosaur Mummies” Could Form

It is important to make clear that what a palaeontologist refers to as a “dinosaur mummy” is not the same as the mummified remains of an Egyptian deity. The skin and other soft tissues are permineralised, they are rock, although it is noted that molecular sampling of this Edmontosaurus specimen yielded putative dinosaurian biomarkers such as evidence of degraded proteins, suggesting that soft tissue was preserved directly in this specimen.

Generally, the two presumed prerequisites for mummification, that of being exposed on the surface for some time to permit the corpse to desiccate and rapid burial are incompatible. So, the researchers propose a new theory on how a “dinosaur mummy” could form:

  • A corpse is scavenged creating puncture marks to allow fluids and gases to escape.
  • Smaller organisms such as invertebrates and microbes exploit these punctures to access the internal organs and other parts of the skeleton.
  • Consumption from within in conjunction with decomposition allows the skin to deflate and to drape over the underlying bones that are more resistant to feeding and decay.
Edmontosaurus soft tissue preservation pathway.
Proposed soft tissue preservational pathway for the Edmontosaurus fossil. Incomplete predation and/or scavenging of the carcass creates openings in the body wall through which fluids and gasses can escape (A). Invertebrates and microbes (B) use those openings to access the internal tissues. Removal of internal soft tissues and drainage of fluids and gasses associated with decomposition allows the deflated skin and other dermal tissues to desiccate and drape over the underlying bones (C). Illustration by Becky Barnes. Picture credit: Drumheller et al (PLoS One).

The scientists hope that this new paper will help with the excavation, collection and preparation of fossils. The presence of soft tissues and biomarkers such as degraded proteins demonstrate that rapid burial may not be a pre-requisite to permit their preservation. As a result, such evidence as skin, soft tissue and biomarkers may be more common in the fossil record than previously thought.

The scientific paper: “Biostratinomic alterations of an Edmontosaurus “mummy” reveal a pathway for soft tissue preservation without invoking ‘exceptional conditions'” by Stephanie K. Drumheller, Clint A. Boyd, Becky M. S. Barnes and Mindy L. Householder published in PLoS One.

9 10, 2022

Travels with Trilobites Book Review

By | October 9th, 2022|Book Reviews, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|1 Comment

Everything Dinosaur team members have had the opportunity to review a new book that documents the evolutionary history of the enigmatic Trilobita. Trilobites evolved during the Cambrian, they are arguably one of the most successful types of animal to have ever lived, with more than 25,000 species named and described to date. Life-long trilobite devotee Andy Secher (American Museum of Natural History, New York), has compiled a comprehensive, and beautifully illustrated book that tells their story, outlines their origins and looks at their amazing variety.

Front cover of "Travels with Trilobites".
The front cover of the beautifully illustrated “Travels with Trilobites” by Andy Secher published by Columbia University Press.

Travels with Trilobites

With forewords by Niles Eldredge, Kirk Johnson and Mark Norell, this book provides a detailed examination of the different genera of trilobites that existed in each geological period, starting with the Class’s evolutionary origins in the Early Cambrian to their eventual demise at the end of the Permian, more than 250 million years later.

Senticucullus elegans fossil.
One of the hundreds of stunning colour photographs from the book “Travels with Trilobites”, many fossils are from the author’s own collection. This beautiful fossil is an example of Senticucullus elegans from the Lower Silurian, Xiushan Formation (Hunan Province, China).

Feeding, Moulting and Reproduction

The author, who is also a co-editor of the American Museum of Natural History’s dedicated trilobite website, explores some of the world’s most famous Palaeozoic Lagerstätten including Kangaroo Island off the coast of South Australia, the Burgess Shale (British Columbia), the Chengjiang biota (Yunnan Province, China) and the Valongo Formation of Portugal. He documents the trilobites associated with each of these significant fossil locations and also embellishes the history of the Trilobita by including numerous “rapid reports” from other fossiliferous locations.

Travels with Trilobites examines the biology of these remarkable arthropods with the author outlining the development of trilobite eyes, how they breathed, their moulting behaviour, feeding and reproduction. There is even a small section looking at the trilobite fossils associated with the Site of Special Scientific Interest (SSSI) at Wren’s Nest (Dudley, Birmingham, England).

Trilobite Gill Fossil
One of the exceptionally rare trilobite specimens preserved in iron pyrite (fool’s gold) that led to the gill discovery. Research into the enigmatic Trilobita continues. Picture Credit: Jin-bo Hou/University of California Riverside.

Published by Columbia University Press

Published by Columbia University Press, Travels with Trilobites is an exquisite book and we at Everything Dinosaur recommend it. This book would make an ideal gift for the amateur fossil hunter.

The last section of this enjoyable book, deals with such varied topics as how to spot fake fossils, preparing trilobite fossils, fossil shows around the world and provides an insight into the motivations of specialist trilobite fossil collectors.

Travels with Trilobites – ISBN number: 978-0-231-20096-7 (hardback book)

Total number of pages – 416

Expect to be able to pick up this superb volume for around £30.00 ($40.00 USD)

Visit the Columbia University Press website and search for either the author (Andy Secher) or “Travels with Trilobites”: Columbia University Website.

6 10, 2022

Spotting A Hadrosaur

By | October 6th, 2022|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Sometimes serendipity and palaeontology combine, for example, a sharp-eyed field team member spotting a hadrosaur fossil specimen eroding out of a small hill in the Dinosaur Provincial Park (Alberta, Canada). The fossils could represent a rare skeleton of a juvenile and there is evidence that skin impressions have been preserved.

Whilst hadrosaur fossils are relatively common in this part of southern Alberta, the animal’s tail and right hind foot are orientated in the hillside to suggest that the entire skeleton may still be preserved within the rapidly eroding mudstone.

Standing next to the exposed hadrosaur skeleton.
Brian Pickles (left) and Caleb Brown (right) stand next to the exposed skeleton. Picture credit: Melissa Dergousoff/University of Reading.

Potentially a Very Significant Fossil Discovery

Whole dinosaur skeletons are extremely rare, this specimen tentatively referred to as a “dinosaur mummy” could provide important new information on juvenile hadrosaurs and the ontogeny of duck-billed dinosaurs.

Diagram of potential hadrosaur specimen
A diagram of the potential hadrosaur skeleton showing exposed parts with skin impressions and the potential orientation of the rest of the skeleton. Picture credit: Caleb Brown.

Spotting a Hadrosaur

The exposed caudal vertebrae (tail bones) show preserved skin impressions as does the exposed right ankle. The size of the bones and the distance between the tail and the astragalus (ankle) suggest that these are the fossilised remains of a young hadrosaur.

Close-up view of the exposed caudal vertebrae with preserved skin impressions.
A close-up view of the exposed caudal vertebrae with preserved skin impressions. Picture credit: Royal Tyrrell Museum of Palaeontology.
View of the exposed ankle bones with skin impressions.
A view of the exposed ankle bones with skin impressions. Picture credit: Royal Tyrrell Museum of Palaeontology.

Discovering a Duck-billed Dinosaur

During a field school scouting visit in 2021 to look for possible excavation sites, Dr Brian Pickles (University of Reading) was leading a small team examining one location when volunteer crew member Teri Kaskie spotted the fossil skeleton protruding from the hillside.

The "Hadrosaur Hill"
Teri Kaskie (right) and (left) Melissa Dergousoff stand next to the hill containing the hadrosaur skeleton. Picture credit: Brian Pickles University of Reading.

The first international palaeontology field school is taking place, involving academics and students from the University of Reading and the University of New England in Australia. In collaboration with researchers from the Royal Tyrrell Museum (Drumheller, Alberta), the team are working together to excavate the skeleton and ensure the material that remains in the hill is protected from the elements.

The first part of the conservation work involves coating the fossil site in a thick layer of mud, to help conserve the delicate fossils and to prevent erosion.

Covering the exposed fossils with mud
Covering the exposed fossils with mud to provide protection. Picture credit: Royal Tyrrell Museum of Palaeontology.

An Exciting Fossil Discovery

Commenting on the significance of this hadrosaur fossil find, Dr Pickles stated:

“This is a very exciting discovery, and we hope to complete the excavation over the next two field seasons. Based on the small size of the tail and foot, this is likely to be a juvenile. Although adult duck-billed dinosaurs are well represented in the fossil record, younger animals are far less common. This means the find could help palaeontologists to understand how hadrosaurs grew and developed.”

Vertebrate palaeontologist from the Royal Tyrrell Museum, Dr Caleb Brown added:

“Hadrosaur fossils are relatively common in this part of the world but another thing that makes this find unique is the fact that large areas of the exposed skeleton are covered in fossilised skin. This suggests that there may be even more preserved skin within the rock, which can give us further insight into what the hadrosaur looked like.”

Protecting the exposed hadrosaur fossils
The burlap screen erected over the exposed fossils to help protect the material from erosion. Picture credit: Royal Tyrrell Museum of Palaeontology.

A Substantial Project

Collecting the entire skeleton is going to take many months and the site will have to be closed down and secured as the weather worsens towards winter. It may take several field seasons to complete this work. Once the specimen has been removed from the field, it will be delivered to the Royal Tyrrell Museum’s Preparation Laboratory, where skilled technicians will work to uncover and conserve the fossilised bones.

At this time, the scientists are unsure as to how complete the specimen is and which genus the fossils represent. Species identification will only be possible if a substantial proportion of the skeleton, including skull material can be recovered.

Exposed hadrosaur skeletal material in the Dinosaur Provincial Park Formation
Brian Pickles and Caleb Brown stand next to the exposed skeleton with an illustration showing estimated skeleton size and potential position. Picture credit: Melissa Dergousoff University of Reading with diagram by Caleb Brown.

Which Hadrosaur?

Several different types of hadrosaur are known from the Dinosaur Provincial Park Formation (Campanian faunal stage). Lambeosaurines are represented by Corythosaurus, Parasaurolophus and Lambeosaurus whilst members of the Saurolophinae subfamily represented include Gryposaurus and Prosaurolophus. As more of the skeleton is prepared, the researchers are hopeful that they will be able to confirm the species.

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

5 10, 2022

Unravelling the Ancestry of the Pterosauria

By | October 5th, 2022|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A fossil specimen found in Scotland more than 100 years ago is helping to unravel the ancestry of the Pterosauria. A new study of tiny and difficult to interpret fossils representing a reptile named Scleromochlus taylori has provided palaeontologists with a fresh perspective on the evolution of the pterosaurs.

The research, published in the academic journal “Nature”, was undertaken by scientists led by Dr Davide Foffa, a Research Associate at National Museums Scotland, and now a Research Fellow at the University of Birmingham. The study, which involved analysis of the fossils using Computed Tomography (CT scans), has enabled the first, accurate skeletal reconstruction of Scleromochlus taylori.

An early ancestor of the Pterosauria
A tiny reptile measuring approximately 20 cm in length, Scleromochlus is now thought to be an early ancestor of the Pterosauria. Picture credit: Gabriel Ugueto.

Anatomical Details Reveal Link with the Pterosauromorpha

The CT scans revealed new anatomical details that conclusively identify the Scleromochlus genus as a close pterosaur relative. Phylogenetic assessment places this small, agile reptile within a group known as Pterosauromorpha. The Pterosauromorpha comprises pterosaurs and their close relatives the lagerpetid reptiles.

Scleromochlus fossil casts (ancestry of the Pterosauria).
Scleromochlus fossil Casts (NHMUK-PV-R3557). Casts created enabled the scientists to reconstruct the skeleton. Picture credit: London Natural History Museum/University of Birmingham.

Identifying the Ancestry of the Pterosauria (Lagerpetonidae)

Geographically widespread in the Late Triassic, the Lagerpetonidae were typically small and fleet-footed reptiles, classified as basal avemetatarsalians, the branch of the Archosauria leading to birds, dinosaurs and the Pterosauria. Previously thought to be close to the evolutionary tree of the Dinosauria, more recent research, including this newly published paper suggests that the lagerpetids were closer to the pterosaurs (members of the Pterosauromorpha).

Most lagerpetids are described as being about the size of cat or small dog, however, Scleromochlus was smaller, with an estimated body length of around 20 cm.

This new study supports the hypothesis that the first flying reptiles (pterosaurs) evolved from small, likely bipedal ancestors. The placement of the lagerpetids within the avemetatarsalians had caused extensive debate. This paper argues that Scleromochlus, represented an evolutionary step in the direction of pterosaurs.

Poorly Preserved Fossils – the Elgin Reptiles

Analysis of the Scleromochlus fossil material using more traditional methods is extremely difficult. The non-destructive CT scans enabled the research team to examine the fossilised bones in exquisite detail and revealed new anatomical details that had not been observed before.

The sandstone block containing the bones come from Morayshire in north-eastern Scotland, near to the town Elgin. Collectively fossils of vertebrates from these deposits are known as the Elgin Reptiles. The fossils are held mostly in the collections of National Museums Scotland, Elgin Museum and the Natural History Museum. The latter holds Scleromochlus, which was originally found at Lossiemouth.

Scleromochlus fossil (ancestry of the Pterosauria).
A Scleromochlus fossil. Picture credit: Professor Paul Barrett London Natural History Museum/University of Birmingham.

Ancestry of the Pterosauria

Commenting on the significance of the research, Dr Foffa stated:

“It’s exciting to be able to resolve a debate that’s been going on for over a century, but it is far more amazing to be able to see and understand an animal which lived 230 million years ago and its relationship with the first animals ever to have flown. This is another discovery which highlights Scotland’s important place in the global fossil record, and also the importance of museum collections that preserve such specimens, allowing us to use new techniques and technologies to continue to learn from them long after their discovery.”

Professor Paul Barrett at the Natural History Museum added:

“The Elgin reptiles aren’t preserved as the pristine, complete skeletons that we often see in museum displays. They’re mainly represented by natural moulds of their bone in sandstone and – until fairly recently – the only way to study them was to use wax or latex to fill these moulds and make casts of the bones that once occupied them. However, the use of CT scanning has revolutionized the study of these difficult specimens and has enabled us to produce far more detailed, accurate and useful reconstructions of these animals from our deep past.

Scleromochlus fossil casts (close view)
A close-up view of a cast of NHMUK-PV-R3557 with clearly defined Scleromochus fossil bones. Picture credit: London Natural History Museum/University of Birmingham.

The First Vertebrates to Evolve Powered Flight

Co-author of the scientific paper, professor Sterling Nesbitt (Virgina Tech) commented:

“Pterosaurs were the first vertebrates to evolve powered flight and for nearly two centuries, we did not know their closest relatives. Now we can start filling in their evolutionary history with the discovery of tiny close relatives that enhance our knowledge about how they lived and where they came from.”

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

The scientific paper: “Scleromochlus and the early evolution of the Pterosauromorpha” by Davide Foffa, Emma M. Dunne, Sterling J. Nesbitt, Richard J. Butler, Nicholas C. Fraser, Stephen L. Brusatte, Alexander Farnsworth, Daniel J. Lunt, Paul J. Valdes, Stig Walsh and Paul M. Barrett published in Nature.”

28 09, 2022

Ancient “Sharks” Appeared Much Earlier

By | September 28th, 2022|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Newly published research suggests that ancient “sharks” appeared much earlier than previously thought. A fossil from China represents a new species of jawed fish (Qianodus duplicis) and its discovery suggests that fishes with true jaws first evolved in the Early Silurian.

Qianodus duplicis life reconstruction
Qianodus duplicis, a new genus and species of an early Silurian gnathostome. Picture credit: Heming Zhang/University of Birmingham.

An Early Silurian Origin of Shark-like Jaws

The scientific paper, published in the journal “Nature” identifies Q. duplicis as the earliest record of a toothed gnathostome known to science. Its discovery extends the record of toothed gnathostomes by some 14 million years from the Late Silurian into the Early Silurian (around 439 million years ago).

The fossils (a handful of tiny teeth), found in China represent the earliest direct evidence for jawed vertebrates known to science.

Previously, the earliest jawed fish to be positively identified, included species from the Late Silurian, fossils thought to date from around 424 million years ago. These include the placoderms (Class Placodermi) partially armoured gnathostomes, and sarcopterygians, bony “lobe-finned” fishes found initially in China and Vietnam.

Confirming Evidence from Fossil Fish Scales

Co-author of the paper, Dr Ivan Sansom (University of Birmingham), commented:

“Until this point, we’ve picked up hints from fossil scales that the evolution of jawed fish occurred much earlier in the fossil record, but have not uncovered anything definite in the form of fossil teeth or fin spines.”

Construction workers building a new road in Guizhou Province uncovered fossil material and field teams from the Chinese Institute of Vertebrate Palaeontology and Palaeoanthropology (IVPP) and the Qujing Normal University (QJNU), were despatched to take samples and to analyse the Silurian-aged deposits.

The scientists found numerous scales, but also recovered several miniscule fossil teeth between 1.5 mm and 2.5 mm in length.

Dr Sansom explained:

“Scales are relatively easy to find because they are so plentiful, but teeth are much scarcer. The scale and speed at which IVPP and QJNU colleagues were able to sift through the material enabled us to identify these scarce remains more effectively than in previous projects.”

Around twenty of the tiny fossil teeth turned out to be from the same species (Qianodus duplicis). From the arrangement of the teeth and their morphology, the team established that they would have come from a fish with an arched jaw margin, with offset tooth rows, similar to those found in extant sharks. The team used a range of techniques, including Computed Tomography (CT scans), to establish a date for the samples.

What’s in a Name?

The new species Qianodus duplicis comes from “Qian” the ancient name for Guizhou Province, “odus” from the Greek for tooth, and duplicis, or double, referring to the paired rows of teeth.

A Cartilaginous Fish – Fanjingshania renovata

In a separate paper, also published today in Nature, the team also identified fossil elements that relate to “fin spines”, bony projections in front of the fins which can be seen today on Port Jackson sharks. These spiny structures form the basis for the identification of a new species Fanjingshania renovata named after Mount Fanjingshan which is close to the locality from where the fossil material was collected. The species name “renovata”, acknowledges renewal, the remodelling of the base of the spines and scales.

Fanjingshania renovata life reconstruction.
Fanjingshania renovata life reconstruction. Picture credit: Heming Zhang/University of Birmingham.

Lead author of both papers Dr Plamen Andreev (Qujing Normal University), commented:

“The early so-called “spiny sharks” had these features on all of their fins, but the examples that we have found belong to a much earlier period. These are the first creatures that we would recognise today as fish-like, evolving from creatures often referred to as “clams with tails”, from earlier in the Ordovician period.”

Ancient “Sharks” Appeared Much Earlier

Cartilaginous fish (chondrichthyans), including sharks, separated off at some point from osteichthyans (bony fish and tetrapods), from which our own species eventually evolved. The point at which this occurred, however, is obscured within ghost lineages in the Ordovician, where only hints in the fossil record have been found. Precisely how and when this separation happened, therefore, remains ambiguous.

Ancient "sharks" appeared much earlier.
Fanjingshania life reconstruction in lateral view. Picture credit: Heming Zhang/University of Birmingham.

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

The scientific paper: “The oldest gnathostome teeth” by Plamen S. Andreev, Ivan J. Sansom, Qiang Li, Wenjin Zhao, Jianhua Wang, Chun-Chieh Wang, Lijian Peng, Liantao Jia, Tuo Qiao and Min Zhu published in Nature.

The scientific paper announcing Fanjingshania renovata: “Spiny chondrichthyan from the lower Silurian of South China” by Plamen S. Andreev, Ivan J. Sansom, Qiang Li, Wenjin Zhao, Jianhua Wang, Chun-Chieh Wang, Lijian Peng, Liantao Jia, Tuo Qiao and Min Zhu published in Nature.

16 09, 2022

A Devonian Heart

By | September 16th, 2022|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Researchers have discovered a 380-million-year-old fossilised heart, along with other internal organs of prehistoric fish. This exciting discovery is not only helping palaeontologists to understand the internal organs of placoderms, these fossils are also providing a fresh perspective on our own evolution.

The Gogo fish fossil where the 380-million-year-old, 3-D preserved heart was discovered by the research team.
The Gogo fish fossil where the 380-million-year-old, 3-D preserved heart was discovered by the research team. Picture credit: Curtin University.

Fossilised Internal Organs in Ancient Armoured, Jawed Fish

The remarkably well-preserved fossils representing the Devonian placoderm Compagopiscis, come from the famous Gogo Formation, in the Kimberley region of Western Australia. The Gogo Lagerstätte preserves the fauna that once thrived on an ancient, shallow water reef. The fossils are thought to be around 380 million years old (Frasnian faunal stage of the Late Devonian).

Gogo fish diorama
Gogo fish diorama at the West Australia Museum Boola Bardip depicting the typical fauna associated with the Gogo Lagerstätte. Typical inhabitants of a tropical reef that existed approximately 380 million years ago. Picture credit: Curtin University.

Soft Tissues Including Liver and Intestines but No Evidence of Lungs

The international research team led by scientists from Curtin University and the Western Australia Museum have published their findings in the academic journal “Science”. They have identified a number of internal organs preserved in three-dimensions including the liver and intestines. Additionally, the fossils show that the lungs are absent, refuting the hypothesis that lungs are ancestral in jawed vertebrates.

CT scans and interpretive models showing the heart of the placoderm Compagopiscis.
CT scans and interpretive models showing the heart of the placoderm Compagopiscis. Picture credit: Curtin University.

Details Revealed by Computerised Tomography

In collaboration with scientists at the Australian Nuclear Science and Technology Organisation in Sydney and the European Synchrotron Radiation Facility in Grenoble, France, researchers used neutron beams and synchrotron x-rays to scan the specimens, still embedded in limestone concretions. They constructed three-dimensional, computer-generated images of the soft tissues inside them based on the different densities of minerals deposited by the bacteria and the surrounding rock matrix.

Lead researcher and John Curtin Distinguished Professor Kate Trinajstic (Curtin’s School of Molecular
and Life Sciences and the Western Australian Museum), commented that to find three-dimensionally preserved tissues in Devonian fossils was an extremely rare event.

Professor Trinajstic explained:

“As a palaeontologist who has studied fossils for more than 20 years, I was truly amazed to find a 3-D and
beautifully preserved heart in a 380-million-year-old ancestor. Evolution is often thought of as a series of small steps, but these ancient fossils suggest there was a larger leap between jawless and jawed vertebrates. These fish literally have their hearts in their mouths and under their gills – just like sharks today.”

The Complex Heart of an Arthrodiran

This is the first time a 3-D representation of the heart of a member of the Arthrodira has been found. The Arthrodira are an extinct Order of jawed, armoured fish within the Class Placodermi. They thrived in the Devonian and some arthrodirans evolved into apex predators such as the huge Dunkleosteus.

Dunkleosteus on display.
The spectacular Dunkleosteus exhibit. A giant apex predator of the Devonian. Picture credit: Everything Dinosaur.

The surprising complex heart is s-shaped and consists of two chambers with the smaller chamber sitting on top. Professor Trinajstic stated that these features were advanced in such early vertebrates, offering scientists a unique perspective on how the head and neck region began to change to accommodate jaws, a critical stage in the evolution of animals with backbones.

Reconstruction of arthrodire internal anatomy.
Reconstruction of arthrodire internal anatomy. Picture credit: Curtin University.

Learning About the Anatomy of a Primitive Jawed Fish

The discovery and subsequent detailed analysis of these mineralised soft tissues, in combination with earlier studies looking at muscle structure, placoderm embryos and evidence of viviparity makes the Gogo Lagerstätte an exceptionally important fossil resource as researchers strive to improve their knowledge of early vertebrates.

Professor Trinajstic added:

“For the first time, we can see all the organs together in a primitive jawed fish, and we were especially surprised to learn that they were not so different from us. However, there was one critical difference – the liver was large and enabled the fish to remain buoyant, just like sharks today. Some of today’s bony fish such as lungfish and bichirs have lungs that evolved from swim bladders, but it was significant that we found no evidence of lungs in any of the extinct armoured fishes we examined, which suggests that they evolved independently in the bony fishes at a later date.”

Professor Kate Trinajstic inspects the ancient fossils at the Western Australia Museum.
Professor Kate Trinajstic inspects the ancient fossils at the Western Australia Museum Boola Bardip. Picture credit: Curtin University.

The Stuff of Palaeontologists’ Dreams

Co-author of the scientific paper, Professor John Long (Flinders University, Adelaide, South Australia) commented:

“These new discoveries of soft organs in these ancient fishes are truly the stuff of palaeontologists’ dreams, for without doubt these fossils are the best preserved in the world for this age. They show the value of the Gogo fossils for understanding the big steps in our distant evolution. Gogo has given us world firsts, from the origins of sex to the oldest vertebrate heart, and is now one of the most significant fossil sites in the world. It’s time the site was seriously considered for world heritage status.”

A cladogram depicting the evolution of the heart in early vertebrates.
A cladogram depicting the evolution of the heart in early vertebrates. Picture credit: Curtin University.

To read an earlier blog post about a fossil from the Upper Devonian Gogo Formation that indicates live birth (viviparity) in placoderms: Evidence of Live Birth (Viviparity) in a 380-million-year-old Fish.

Exceptional Fossils Meet Exceptional Technology

Co-author of the paper Professor Per Ahlberg (Uppsala University, Sweden) explained that access to state-of-the-art, non-destructive scanning technology enabled scientists to make such exceptional discoveries.

Professor Ahlberg explained:

“What’s really exceptional about the Gogo fishes is that their soft tissues are preserved in three dimensions. Most cases of soft-tissue preservation are found in flattened fossils, where the soft anatomy is little more than a stain on the rock. We are also very fortunate in that modern scanning techniques allow us to study these fragile soft tissues without destroying them. A couple of decades ago, the project would have been impossible.”

The preserved stomach of a Gogo fish fossil under the microscope.
The preserved stomach of a Gogo fish fossil under the microscope. Picture credit: Curtin University.

A Collaborative Effort

The research was truly a collaborative effort not only involving the Australian Nuclear Science and Technology Organisation and the European Synchrotron Radiation Facility, but also scientists from Flinders University, the Western Australian Museum, Uppsala University, South Australia Museum and Monash University’s Australian Regenerative Medicine Institute.

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

The scientific paper: “Exceptional preservation of organs in Devonian placoderms from the Gogo lagerstätte” by Kate Trinajstic, John A. Long, Sophie Sanchez, Catherine A. Boisvert, Daniel Snitting, Paul Tafforeau, Vincent Dupret, Alice M. Clement, Peter D. Currie, Brett Roelofs, Joseph J. Bevitt, Michael S. Y. Lee and Per E. Ahlberg published in the journal Science.

9 09, 2022

Unravelling the Plateosauridae – A New Species is Announced (T. maierfritzorum)

By | September 9th, 2022|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Researchers have re-examined the fossilised remains of a Late Triassic, herbivorous dinosaur that had been assigned to the Plateosaurus genus and determined that the fossils represent a new species. The new dinosaur has been named Tuebingosaurus maierfritzorum and unlike Plateosaurus it was an obligate quadruped.

Tuebingosaurus fossils and scale drawing.
Skeletal silhouette of Tuebingosaurus with ascribed fossil bones shown in white. Silhouette of person provides the scale. The attribution of the bone marked in grey (fibula) is uncertain. Picture credit: Omar Rafael Regalado Fernandez / Ingmar Werneburg.

The genus Plateosaurus was erected in 1837 (Hermann von Meyer), before the term Dinosauria was coined, it was one of the first dinosaurs to be scientifically described. It has earned a reputation as somewhat of a taxonomic waste basket with numerous species assigned to it, often based on poorly preserved or fragmentary fossil remains.

Researchers at the University of Tübingen’s Senckenberg Centre for Human Evolution and Palaeoenvironment in Germany reassessed fossil bones discovered in Trossingen in 1922 and identified several unique anatomical traits leading them to conclude that these remains did not represent Plateosaurus as had previously been thought. Indeed, the bones are so different that they do not belong to a member of the Plateosauridae family, but most likely represent a member of the related clade the Massopoda.

Tuebingosaurus hib bones viewed by the scientists.
Ingmar Werneburg (left) and Omar Rafael Regalado Fernandez (right) in the archive of the paleontological collection at Tübingen. The hips of Tuebingosaurus maierfritzorum can be seen in the foreground. Picture credit: Valentin Marquardt/Universität Tübingen.

Broader and More Robust Hips

Writing in the journal “Vertebrate Zoology”, the researchers, Dr Omar Rafael Regalado Fernandez and Dr Ingmar Werneburg demonstrate that the hips are much broader and more robust when compared with plateosaurs. In addition, the limb bones such as the femur are unusually large and the fused sacral vertebrae are characteristic of an obligate quadruped and not Plateosaurus that are believed to have been facultative bipeds (quadrupeds, but capable of walking on their hind legs if the need arose).

Tuebingosaurus fossils in display cabinet.
Two phalanges (toe bones) (centre) of Tuebingosaurus maierfritzorum in a display cabinet at the Württemberg Hall. Picture credit: Valentin Marquardt/Universität Tübingen.

The Swabian Alb Mountains

The fossil bones of Tuebingosaurus maierfritzorum display characteristics of sauropods, the super-sized, long-necked dinosaurs such as Diplodocus, Brontosaurus and Brachiosaurus that dominated terrestrial faunas some fifty million years after Tuebingosaurus roamed. The fossil material is part of Tübingen’s paleontological collection. It originated from a quarry site near Trossingen at the edge of the Swabian Alb mountain range in Baden-Württemberg (Germany). The area is famous for its extensive plateosaur bonebeds and the huge amount of Plateosaurus fossils collected confirm that this lizard-hipped genus was extremely common in the Late Triassic and that Plateosaurus lived in large herds.

Scanning a Tuebingosaurus foot bone.
Three-dimensional image of a footbone from Tuebingosaurus being made with a handheld laser scanner. Picture credit: Valentin Marquardt/Universität Tübingen.

Following the in-depth analysis, which included scanning limb bones to provide a data source to compare to Plateosaurus fossils, the scientists concluded that these fossils represent a dinosaur more closely related to the Sauropoda than Plateosaurus.

The Trossingen Biota

Examination of the matrix material found in association with the Tuebingosaurus fossils, and the surface condition of the bones suggests that this dinosaur sunk into a swamp when it died. The bones on the left side of the body were exposed on the surface for several years and show signs of weathering. Several different types of dinosaur are known from the Plateosaurus dominated Trossingen Formation, which dates to the Norian-Rhaetian faunal stages of the Late Triassic. Coelophysoids such as Liliensternus, which at around 5 metres long, could have predated upon Tuebingosaurus juveniles have been found. The Trossingen Formation has also yielded fragmentary fossils of other miscellaneous theropods plus evidence of different types of prosauropod.

The large rauisuchian Teratosaurus (T. suevicus) is also known from the Trossingen Formation and in the image below an unfortunate Tuebingosaurus is being attacked by this six-metre-long, predator from the crocodilian lineage of the Archosauria.

Tuebingosaurus life reconstruction.
Reconstruction how the death of Tuebingosaurus maierfritzorum may have occurred. Bones of the predatory archosaur Teratosaurus were also found in Trossingen. However, it has only been proven that Tuebingosaurus fell on its right side. Weathering indicates that the bones on the left side of the body probably lay for several years on the surface. Picture credit: Marcus Burkhardt.

Tuebingosaurus maierfritzorum

The individual bones of Tuebingosaurus maierfritzorum (pronounced Too-bin-go-sore-us my-ah-frits-zor-um), had been stored separately but have now been united in their own permanent display case. The genus name honours the university city of Tübingen and its inhabitants, whilst the specific name pays tribute to two German zoologists, Professor Wolfgang Maier from Tübingen and Professor Uwe Fritz from Senckenberg Natural History Collections in Dresden.

This new dinosaur species has now been described in the latest edition of the Senckenberg Natural Science Society’s journal Vertebrate Zoology, which also pays tribute to Wolfgang Maier on his 80th birthday.

Ingmar Werneburg (left) and Omar Rafael Regalado Fernandez (right) hold a femur from Tuebingosaurus maierfritzorum
Researchers Ingmar Werneburg (left) and Omar Rafael Regalado Fernandez (right) hold a femur from Tuebingosaurus maierfritzorum. Picture credit: Valentin Marquardt/Universität Tübingen.

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

The scientific paper: “A new massopodan sauropodomorph from Trossingen Formation (Germany) hidden as ‘Plateosaurus’ for 100 years in the historical Tübingen collection” by Omar Rafael Regalado Fernández, Ingmar Werneburg published in Vertebrate Zoology.

6 09, 2022

A New Abelisaurid from Argentina

By | September 6th, 2022|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A new species of dinosaur has been described from fossils found in Neuquén Province (Argentina). Named Elemgasem nubilus it is the first unambiguous abelisaurid known from the Coniacian faunal stage of the Late Cretaceous.

Elemgasem life reconstruction
A life reconstruction of the newly described abelisaurid Elemgasem nubilus depicted with other Late Cretaceous prehistoric fauna associated with the Portezuelo Formation of Patagonia. Picture credit: Abel Germán Montes.

A field team of CONICET researchers have excavated the fragmentary remains of a new species of carnivorous dinosaur from Upper Cretaceous exposures near to the city of Plaza Huincul, in the province of Neuquén in Patagonia (Argentina). The fossils come from the Portezuelo Formation and represent an individual animal around four metres in length and standing approximately two metres tall. Bone histology revealed that this abelisaurid was around eight years old when it died. The histological analysis suggests that Elemgasem probably would not have grown much bigger, making this predator much smaller than related abelisaurids such as Carnotaurus and Ekrixinatosaurus.

Regarded as a sub-adult, the scientists who include co-author Rodolfo Coria (Universidad Nacional de Río Negro, Argentina), writing in the journal of The Palaeontological Association conclude that this dinosaur had already reached sexual maturity.

Palaeontologist Rodolfo Coria excavates dinosaur fossils
Co-author of the scientific paper Rodolfo Coria (Universidad Nacional de Río Negro) excavating fossils in Neuquén Province. Picture credit: CONICET.

Documenting the Evolution of the Abelisauridae

The Abelisauridae are a diverse group of medium-to-large-sized predatory dinosaurs predominately associated with the landmass of Gondwana. Numerous genera have been described based on fossils found in the Southern Hemisphere and they are known from almost all parts of Gondwana in all the faunal stages associated with the Late Cretaceous, except for the Coniacian (90 to 86 mya approximately).

This period in Earth’s history is marked by a turnover in terrestrial and marine fauna due to global climate change leading to worldwide extinctions.

Explaining the significance of these fossils, co-author Rodolfo Coria stated:

“The identification of a new species is always a scientifically relevant event, especially if the species belongs to an emblematic family of carnivorous dinosaurs such as the abelisaurs. Elemgasem represents a key piece in the puzzle of the evolution of this group, which began to be put together with the first findings of José Bonaparte, the most important Argentinean vertebrate palaeontologist of the 20th century – in the 1980s”

Although the fossil material is fragmentary, a new genus has been erected based on several autapomorphies including notable rugosity on the lateral surface of the fibula and the shape of the tail bones which are different from any other abelisaurid described to date.

Views of the distal portion of the right femur of Elemgasem.
Views of the distal portion of the fossilised right femur of Elemgasem nubilus with an accompanying line drawing that shows the position of the bone. Picture credit: Mattia A. Baiano.

The First Abelisaurid from the Portezuelo Formation (New Abelisaurid)

Elemgasem is the first abelisaurid described from fossils from the Portezuelo Formation and it was part of a diverse dinosaur-dominated terrestrial fauna with several different types of theropod present including dromaeosaurids, alvarezsaurids and megaraptorids.

Phylogenetic analysis indicates the E. nubilus could be tentatively assigned to the Brachyrostra tribe within the Carnotaurinae subfamily, although the limited amount of fossilised material prevented the researchers from making a more positive taxonomic assessment.

The genus name is derived from the name of a god in the regional Tehuelche culture and the trivial name is from the Latin for “cloudy days”, a reference to the strange, foggy conditions that the dig team encountered whilst they worked in the field.

Elemgasem skeletal reconstruction.
Skeletal reconstruction of Elemgasem nubilus with known fossil elements shown in red. Picture credit: Abel Germán Montes.

Dr Coria added:

“We already knew of abelisaurian forms in older horizons [such as the Cenomanian] or more modern ones [such as the Campanian], so it was predictable that there would be some in intermediate times. What we did not expect was to find a comparatively small abelisaur like Elemgasem, whose size is clearly smaller than the rest of the species in the group, such as Carnotaurus, Aucasaurus or Skorpiovenator.”

It is the first abelisaurid from the Turonian–Coniacian interval and it increases the diversity of this theropod family at a time of marked turnover in the tetrapod fauna of South America.

Rebor has introduced several scale replicas of abelisaurid dinosaurs. To view the extensive range of Rebor models and figures available from Everything Dinosaur: Rebor Figures and Models.

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

The scientific paper: “Elemgasem nubilus: a new brachyrostran abelisaurid (Theropoda, Ceratosauria) from the Portezuelo Formation (Upper Cretaceous) of Patagonia, Argentina” by Mattia A. Baiano, Diego Pol, Flavio Bellardini, Guillermo J. Windholz, Ignacio A. Cerda, Alberto C. Garrido and Rodolfo A. Coria published in Papers in Palaeontology.

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