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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.

4 11, 2018

A New Species of Rebbachisaurid is Named

By | November 4th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|2 Comments

Lavocatisaurus agrioensis – A New Long-Necked Dinosaur from Argentina

A team of palaeontologists from Argentina and Spain have announced the discovery of a new species of long-necked dinosaur from the Early Cretaceous of Argentina.  The dinosaur, represented by a set of bones that indicate the remains of at least three individuals, has been named Lavocatisaurus agrioensis and it will help to shed more light on a rare and enigmatic group of Sauropods known as the rebbachisaurids.

A Skeletal Reconstruction and Photographs of Key Fossils from L. agrioensis

Skeletal reconstruction and fossil bones attributed to Lavocatisaurus agrioensis.

Skeletal reconstruction based on the holotype and paratype specimens of Lavocatisaurus agrioensis.  Scale bars = 10 cm.

Picture Credit: AFP/Agencia CTYS

The picture above shows the skeletal drawing of the adult dinosaur with illustrations of key bones from the excavation.  Most of the neck and the skull has been recovered.  Cranial fossils associated with the Rebbachisauridae are rare, the discovery of these specimens from Agrio del Medio (Neuquén Province, Argentina) will help scientists to better understand taxonomic relationships amongst members of this Sauropod family, largely associated with Gondwanaland fossil deposits.

Fossils of a Family Group?

Writing in the journal “Acta Palaeontologica Polonica”, the scientists report the discovery of one large, presumably adult animal with two smaller sub-adults found in association.  The fossil material come from terrestrial sandstone deposits laid down around 110 million years ago (Aptian to Albian faunal stage of the Early Cretaceous), in an arid environment with isolated oasis and other water sources (Rayoso Formation).

One of the authors of the scientific paper, José Luis Carballido, of the Egidio Feruglio Museum (Argentina), stated:

“We found most of the cranial bones: the snout, the jaws, a lot of teeth, also the bones that define the eye sockets for example and in that way, we were able to create an almost complete reconstruction.  Not only is this the discovery of a new species in an area where you wouldn’t expect to find fossils, but the skull is almost complete.”

The fossils represent one large dinosaur estimated to be around twelve metres in length and two smaller animals around six to seven metres in length.  The research team postulate that this could represent a family group that lived together and perished together, perhaps unable to find a water source in a time of drought.

Preparing to Move Some of the Fossil Material (Lavocatisaurus)

Fossils of Lavocatisaurus are prepared for removal.

The jacketed remains of one of the Lavocatisaurus specimens is prepared for transport away from the dig site.

Picture Credit: AFP/Agencia CTYS

Lead author of the paper, José Ignacio Canudo (Zaragoza University, Spain) added:

“This discovery of an adult and two juveniles also signifies the first record of a group displacement among the Rebbachisaurus dinosaurs.”

The Rebbachisauridae Family

The Rebbachisauridae family of Sauropods are a group of basal members of the Diplodocimorpha clade that includes more famous Late Jurassic dinosaurs such as Diplodocus, Apatosaurus and Brontosaurus.  The rebbachisaurids are known from both Lower Cretaceous and Upper Cretaceous strata and had a wide geographical distribution throughout Gondwana and southern Laurasia with fossils reported from north and central Africa as well as South America and Europe (Spain).

An Illustration of a Typical Rebbachisaurid Dinosaur (R. garasbae)

Rebbachisaurus scale drawing.

Scale drawing of Rebbachisaurus (R. garasbae)

Picture Credit: Everything Dinosaur

3 11, 2018

Elaborate Plumage in Confuciusornis

By | November 3rd, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Patterns on the Feathers of Confuciusornis as Complex as Modern Birds

A team of international scientists, including researchers from the China University of Geosciences (Beijing), the University of Ghent (Belgium) and the University of Texas at Austin (United States), have discovered that the patterns on the feathers of an Early Cretaceous bird may have been very similar to and as complex as the patterns seen on the feathers of extant Aves.  Writing in the academic, on-line journal “PeerJ”, the researchers conclude that the patterning of Confuciusornis feathers probably performed similar functions to the patterning on modern bird’s feathery coats, that is, they provided camouflage and also played a role in display.

Confuciusornis Integumentary Covering – Elaborate Plumage

Study suggests Confuciusornis had elaborate plumage.

Reconstruction of the plumage of Confuciusornis (specimen number CUGB P140).

Picture Credit: Li et al (PeerJ)

Complex Patterning Detected by Sophisticated Chemical Analysis

The specimen studied consists of a slab and counter slab of a single, individual bird from Early Cretaceous deposits in Fengning County, Hebei Province (north-central China).  The fossils are from the vertebrate collection of the China University of Geosciences and represent an example of Confuciusornis sanctus.  The research team identified exceptional feather preservation but poor preservation of the bones, the unusual state of preservation permitted the scientists to identify melanin signals in the fossilised feathers indicating a complex patterning of spots on the wings, throat and on the tuft of feathers at the back of the head forming a small crest.  The shape of the structures that form these patterns in conjunction with chemical analysis confirmed the diagnosis of the pigment melanin.  However, specific colouration associated with the patterns could not be discerned.

The Slab and Counter Slab or a C. sanctus Specimen Reveals Complex Patterning on the Plumage

Evidence of Confuciusornis plumage.

Evidence of plumage diversity in the Confuciusornithidae from the new specimen (CUGB P1401).

Picture Credit: Li et al (PeerJ)

The photograph (above) shows various views of the main slab of the fossil specimen showing details of the plumage.  The dots in (A) indicate places that were subjected to sampling, whereas B and C reveal the crest located on the back of the head.  Parts D and E show elements of the integumentary covering in close detail.

Using a range of analytical techniques including scanning electron microscopy and ion mass spectrometry (ToF-SIMS) the researchers concluded that the elaborate spotting on this specimen exceeds that found in exceptionally-preserved troodontids and compsognathids and rivals that in modern birds, suggesting that plumage patterns evolved greater complexity through avian evolution.

The exact age of the strata is uncertain, although it is believed that the deposits from Fengning County are approximately equivalent in age with the Dawangzhangzi Member of the Yixian Formation, around 122-123 million years old (Aptian faunal stage of the Early Cretaceous).  The data from this study suggests that Confuciusornis had more complex patterning than the patterning identified in Achiornis or in the stripes of the compsognathid Sinosauropteryx.  The research team conclude that this specimen of a primitive bird provides evidence to support the idea that complex patterning of feathers evolved at a relatively early stage in avian evolution.

The Link to Barn Owls

Integumentary patterns and colours play a variety of roles in living birds.  Such patterning in fossil specimens probably performed the same sort of functions and in addition, they can help to inform on the habitat in which the extinct creature lived.  In some modern bird groups, barn owls for example (Strigiformes), it has been observed that the size and placement of the spots on the feathers play a role in mate selection.  Male barn owls tend to prefer females with larger spots.  The patterning identified on this C. sanctus specimen leads to the intriguing idea that for confuciusornithids, just like barn owls, the location and the size of the spots on the plumage played a role in choosing a mate.

The scientific paper: “Elaborate Plumage Patterning in a Cretaceous Bird” by Quango Li, Julia A. Clarke, Ke-Qin Gao, Jennifer A. Peteya and Matthew D. Shawkey published in PeerJ.

30 10, 2018

A New Azhdarchid Pterosaur from France

By | October 30th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Mistralazhdarcho maggii – From the Upper Cretaceous of France

A team of scientists based in France and Belgium have announced the discovery of a new species of pterosaur from Upper Cretaceous rocks in south-eastern France (Bouches-du-Rhône).  The fragmentary bones have been assigned to the Azhdarchidae family of pterosaurs, one of the last groups of flying reptiles to exist and a family that contains giants such as Quetzalcoatlus and Hatzegopteryx.  With a wingspan estimated to be around 4.5 metres, the specimen, believed to be a juvenile, provides evidence of a third azhdarchid pterosaur size class from the cluster of islands that represented continental Europe towards the end of the Mesozoic.

The pterosaur has been named Mistralazhdarcho maggii pronounced (miss-tral-ads-dar-cho may-gee).

A Life Reconstruction of the Newly Described French Azhdarchid Pterosaur – Mistralazhdarcho maggii

Life reconstruction of the pterosaur Mistralazhdarcho maggii.

An illustration of the newly described (2018) azhdarchid pterosaur from France Mistralazhdarcho maggii.

Picture Credit: Pierre Lavaud

One of the Most Complete Pterosaur Fossils Known from Late Cretaceous Europe

Writing in the academic publication the “Journal of Vertebrate Paleontology”, the researchers describe the finding of part of a lower jaw, a neck bone and several other postcranial bones in 2009.  The bones were found in association with each other and therefore, probably represent the fossilised remains of a single pterosaur.  The material comes from the excavation site of Velaux, near Aix-en-Provence and from strata that dates to the Campanian faunal stage of the Late Cretaceous.

Views of the Fossil Material Ascribed to the New Pterosaur Mistralazhdarcho maggii

Mistralazhdarcho maggii fossil material.

Fossil material associated with the newly described French pterosaur Mistralazhdarcho maggii.

Picture Credit: Royal Belgian Institute of Natural Sciences

The photograph (above), shows a part mandible (a) with a distinctive ridge (mandibular symphysis).  A cervical vertebra (b), left humerus (c), left radius (d) and two bones from the hand – metacarpal IV (e) and a finger bone (f).

Although the fossil material is fragmentary, such is the poor fossil record of Late Cretaceous pterosaurs from Europe that these few bones make Mistralazhdarcho one of the most complete European azhdarchids described to date.  In addition, Mistralazhdarcho is the first partial skeleton of a flying reptile excavated from Upper Cretaceous deposits of western Europe.

Related to a North African Pterosaur?

The scientists, which included researchers from the University of Rennes, the Royal Belgian Institute for Natural Sciences and Poitiers University, conclude that Mistralazhdarcho was related to an earlier pterosaur called Alanqa (A. saharica), which lived in North Africa around 95 million years ago.  When Alanqa was first described, back in 2010, it was assigned to the Azhdarchidae, but more recent studies incorporating skull material discovered in 2015, have cast doubt on the taxonomic position of Alanqa.

To read about the discovery of Alanqa saharicaDublin Team Announce the Discovery of a New Pterosaur

An Adult Probably Had a Wingspan of Around 5-6 metres

Examination of the fossil bones suggest that they were not fully ossified and that this was a sub-adult.  The researchers speculate that a fully-grown Mistralazhdarcho would have had a wingspan of around 5 to 6 metres, possibly even bigger.  This size estimate is in between the size estimates given for the two azhdarchids from the Maastrichtian of Romania (Hateg Formation), which also represents the European Late Cretaceous archipelago environment.

A Size Comparison of European Azhdarchid Pterosaurs

European azhdarchid pterosaur comparison.

A comparison of European azhdarchid pterosaurs.

Picture Credit: Everything Dinosaur

Mistralazhdarcho is estimated to be intermediate in size between the medium-sized genus Eurazhdarcho (wingspan of 3 metres) and the enormous Hatzegopteryx (estimated wingspan of 10 metres or more), the two other azhdarchids associated with the island ecosystem of the latest Cretaceous European archipelago.  The different sized pterosaurs might reflect a form of niche partitioning, whereby, different sized animals did not directly compete with each other for resources.

The flying reptile’s genus name is from the “mistral”, a strong, north-westerly wind associated with southern France.  The species name honours the former mayor of Velaux, Jean-Pierre Maggi, without whom, the excavation of the fossil material would not have been possible.

Field Team Members Working at the Velaux Excavation Site

Looking for pterosaur fossils (south-eastern France).

Fossil excavation work at one of the dig sites at Velaux (south-eastern France).

Picture Credit: Royal Belgian Institute of Natural Sciences

The scientific paper: “Mistralazhdarcho maggii, gen. et sp. nov., a New Azhdarchid Pterosaur from the Upper Cretaceous of south-eastern France” by Romain Vullo, Géraldine Garcia, Pascal Godefroit, Aude Cincotta and Xavier Valentin published in the Journal of Vertebrate Paleontology.

29 10, 2018

A Second Mamenchisaurid Dinosaur from Anhui Province is Described

By | October 29th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Anhuilong diboensis – From the Middle Jurassic of Anhui Province

Chinese scientists have published details of a new species of long-necked dinosaur from eastern China.  The fossilised remains, although fragmentary, have permitted the researchers to confidently assign the specimen (AGB 5822), to the Mamenchisauridae family of Sauropods.  The dinosaur has been named Anhuilong diboensis and it suggests that by the Middle Jurassic, mamenchisaurids were already a diverse family.  It is likely that the sandstones and mudstones that form the majority of the fossil bearing, Middle Jurassic-aged strata near Huangshan (Anhui Province), will yield more dinosaur fossils.

A Life Reconstruction of a Typical Mamenchisaurid Dinosaur

Old Long-neck takes a walk

A typical member of the Mamenchisauridae family (Mamenchisaurus).

Picture Credit: Julius Csotonyi/Natural History Museum of Los Angeles County

The Second Member of the Mamenchisauridae from Anhui Province

The fossil material, consisting of the remains of a single forelimb, representing one individual dinosaur (humerus, ulna and radius bones), was distinct enough to permit the scientists, which included researchers from the Chinese Academy of Sciences and the Anhui Geological Museum, to establish a new genus.  Anhuilong diboensis is the second mamenchisaurid to be identified from the Middle Jurassic Hongqin Formation of Shexian, Huangshan (Anhui Province, eastern China).  The first mamenchisaurid from this locality, Huangshanlong anhuiensis, was named and described in 2014.  The authors of the scientific paper describing A. diboensis were also responsible for the earlier study of H. anhuiensis.  A phylogenetic analysis of the limb bones from these two specimens suggest that Anhuilong is the sister taxon of Huangshanlong and with Omeisaurus from Sichuan Province, they together form a sister clade to all other members of Mamenchisauridae.

Views of the Right Humerus of Huangshanlong anhuiensis

Various views of the humerus of the mamenchisaurid Huangshanlong anhuiensis.

Huangshanlong anhuiensis – views of the humerus of a typical mamenchisaurid dinosaur.

Picture Credit: Vertebrata PalAsiatica/Jian-Dong Huang et al

The picture above shows various views of the right humerus (upper arm bone) of H. anhuiensis.  The morphology of limb bones and how they compare to each other (total length of the ulna to the humerus and the total length of the radius to the humerus), are distinct enough for palaeontologists to ascribe them to the Mamenchisauridae and to erect a new genus.

Key

A = humerus viewed from the front.

B = humerus viewed from one side (medial view).

C = humerus viewed from the back.

D = humerus viewed from the other side (lateral view).

E = viewed from the top down (cranial margin pointing upwards)

F = view of a cross section, near the narrowest part of the bone.

G = viewed from underneath (distal view).

The Spread of the Sauropoda

Until recently, palaeontologists had thought that although the Sauropoda were geographically widespread by the Middle Jurassic, sub-groups such as the Mamenchisauridae family and the Diplodocidae had restricted geographical ranges.  However, earlier this year, a diplodocid dinosaur was described from northern China, proving that these long-necked dinosaurs were present in Asia during the Middle Jurassic.  The fossil record for the Mamenchisauridae indicates that these types of Sauropods were restricted to China.

To read the article describing the diplodocid dinosaur (Lingwulong shenqi) from northern China: The First Diplodocid Dinosaur Described from China and the Earliest Known Member of the Diplodocidae

28 10, 2018

A New Species of Archaeopteryx

By | October 28th, 2018|Dinosaur and Prehistoric Animal News Stories, Main Page|0 Comments

Archaeopteryx albersdoerferi – A New Species of Archaeopteryx is Named

Those very rare Archaeopteryx specimens that have been found in the fine-grained, Upper Jurassic deposits of Germany are some of the most intensely researched fossils on our planet.  However, they can still surprise and it seems that we have much to learn about “Urvogel” as the Germans refer to this iconic transitional form between a dinosaur and a true bird.  Writing in the academic journal “Historical Biology”, a team of international researchers have subjected one particular fossil (specimen number eight), to the powerful X-rays of synchrotron microtomography and discovered that this example of the “first bird” is so different from other Archaeopteryx fossils that it merits being categorised as a separate species.

A Life Reconstruction of the Newly Described Archaeopteryx Species (A. albersdoerferi)

Archaeopteryx albersdoerferi life reconstruction.

A life reconstruction of the newly described Archaeopteryx species (A. albersdoerferi).

Picture Credit: Zhao Chuang (supervised by lead author of the scientific paper Martin Kundrát of Uppsala University)

Closer to True Birds in Evolutionary Terms

The scientists, which included researchers from Uppsala University, the Chinese Academy of Geological Sciences and Manchester University’s John Nudds (School of Earth and Environmental Sciences), carried out a three-dimensional analysis of the fossil using the European Synchrotron Radiation Facility (ESRF), located in Grenoble.  The team found that specimen eight is closer to modern birds in evolutionary terms when compared to the other known Archaeopteryx specimens.

Dr Nudds explained:

“By digitally dissecting the fossil we found that this specimen differed from all of the others.  It possessed skeletal adaptations which would have resulted in much more efficient flight.  In a nutshell, we have discovered what Archaeopteryx lithographica evolved into – i.e. a more advanced bird, better adapted to flying – and we have described this as a new species of Archaeopteryx.”

Dr John Nudds with the Archaeopteryx Specimen at the Synchrotron Facility

Dr John Nudds holding an Archaeopteryx fossil specimen.

Dr John Nudds (Manchester University) holding the Archaeopteryx specimen at the European Synchrotron facility (Grenoble, France).

Picture Credit: Manchester University

Differences in the Skeleton – Better Adaptations for Powered Flight

The research team identified numerous, subtle skeletal differences between this specimen and the other Archaeopteryx fossil skeletons.  For example, specimen eight has fused cranial bones, a different pectoral girdle and wing elements and a more robust set of carpals and metacarpals (hand bones).  The X-ray scans revealed that this specimen had very light bones, with numerous air sacs in them.  These characteristics are observed more in modern flying (volant), birds and are not found in the older Archaeopteryx lithographica species.  The fossil studied is the so-called Mörnsheim or Daiting specimen, from strata which is around half a million years younger than the rocks associated with the majority of the German Archaeopteryx fossils.  As such, specimen eight is stratigraphically the youngest Bavarian archaeopterygid.

Archaeopteryx albersdoerferi – “The Phantom”

The Mörnsheim or Daiting fossil has had a colourful history.  It was (allegedly), discovered by a private fossil collector in a quarry near the town of Daiting in southern Bavaria, about twenty miles south of the city of Nuremberg (Germany), sometime in the early 1990’s.  It was incorrectly identified as a Pterosaur and this fossil changed hands several times.  Rumours began to circulate amongst the scientific community that there was another Archaeopteryx specimen but it remained elusive, so much so, that the fossil was nick-named “The Phantom”.  A cast of the fossil was briefly put on display at the Naturkundemuseum in Bamberg (Germany) in 1996 and a short report was written a year later, but this specimen remained out of reach and not accessible for study.

All this changed in 2009, when palaeontologist Raimund Albersdörfer of Schnaittach (Bavaria), purchased the specimen from a private collector and secured its scientific heritage by offering it on long-term loan to the Bavarian State Collection of Palaeontology and Geology in Munich, and obligated himself by contract not to sell the specimen to a non-public entity.  The species name honours the contribution made by Raimund Albersdörfer.  This is not the first time that Raimund has made a privately-owned Theropod specimen available to study.  In 2012, he was honoured by having the trivial name of a feathered dinosaur from southern Germany named after him (Sciurumimus albersdoerferi).

Lead author, Dr Martin Kundrát, commented:

“This is the first time that numerous bones and teeth of Archaeopteryx were viewed from all aspects including exposure of their inner structure.  The use of synchrotron microtomography was the only way to study the specimen as it is heavily compressed with many fragmented bones partly or completely hidden in limestone.”

Is The Really a New Species?

Palaeontologists are aware that this part of Germany where the Archaeopteryx fossil material comes from, was once a series of small islands surrounded by a tropical sea.  The strata were laid down over hundreds of thousands of years and it is therefore quite possible that different species of primitive “dino-bird” evolved over this period.  However, the Mörnsheim specimen was examined using computer tomography that provided an extremely detailed assessment of the fossil material.  It is quite possible, that, if other Archaeopteryx specimens were subjected to the same level of scrutiny, then new information about them would be discovered too.

To read an article from 2016, that reports on the discovery of a twelfth Archaeopteryx specimen, a fossil recovered from strata at least 200,000 years older than other Archaeopteryx fossil material: The Oldest Archaeopteryx in Town

The scientific paper: “The First Specimen of Archaeopteryx from the Upper Jurassic Mörnsheim Formation of Germany” by Martin Kundrát, John Nudds, Benjamin P. Kear, Junchang Lü and Per Ahlberg published in Historical Biology.

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

27 10, 2018

Pachycephalosaurus – Was It Carnivorous?

By | October 27th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Theropod-like Front Teeth Identified in a Pachycephalosaur

Pachycephalosaurus, that dome-headed dinosaur that lived alongside such famous prehistoric animals as T. rex and Triceratops, in the Late Cretaceous of Montana, has always been a bit-player when it comes to depicting life in the very last couple of million years before the extinction of the non-avian dinosaurs.  Its more illustrious contemporaries tend to hog the limelight somewhat.  However, the scientific description of a nearly complete skull and jaws of what has been identified as a juvenile Pachycephalosaurus, might just have revealed a surprising side to this peaceful plant-eater.  The teeth in the front of jaws are triangular and pointed, reminiscent of the dentition of a meat-eating dinosaur.  Could palaeontologists have got Pachycephalosaurus wrong?

A Reconstruction of the Juvenile Pachycephalosaurus Skull and Jaws

Reconstruction of a Juvenile Pachycephalosaurus skull.

A reconstruction of the fossil skull of the juvenile Pachycephalosaurus that has Theropod-like teeth in the front of the jaws.

Picture Credit: Brian Boyle (Royal Ontario Museum)

Front Portion of the Jaws Suggests Omnivory in Certain Pachycephalosaurs

In a presentation made at the annual meeting of the Society of Vertebrate Palaeontology held in Albuquerque, New Mexico, Mark Goodwin (University of California Museum of Palaeontology) and David Evans (Royal Ontario Museum), described a near complete juvenile Pachycephalosaur skull from eastern Montana.  The back of the jaws contained the broad, leaf-shaped teeth which seem well suited to herbivory.  It had been assumed that the teeth in the front of the jaws (premaxilla and the anterior portion of the dentary, immediately behind the predentary), were the same shape.  However, until this fossil specimen was found, no record of the front teeth of these dinosaurs existed.  Palaeontologists may have to re-think their views on the diet of this member of the Hell Creek Formation biota.  The sharp, blade-like triangular teeth located at the front of the mouth seem adapted to ripping and tearing flesh.

The Teeth at the Front of the Jaws are Typical of a Meat-eating Theropod Dinosaur

Pachycephalosaurus Theropod-like teeth.

A close-up view of the teeth in the premaxilla (upper jaw) and the anterior portion of the dentary (lower jaw). Triangular Theropod-like teeth have been identified in a juvenile Pachycephalosaurus.

Picture Credit: Brian Boyle (Royal Ontario Museum) with additional annotation by Everything Dinosaur

Confusing Pachycephalosaurs

Pachycephalosaurus is the largest member of the Pachycephalosauridae family to have been scientifically described and notwithstanding a cameo appearance of a jail-breaking Stygimoloch in the recent “Jurassic World – Fallen Kingdom” movie, perhaps the most famous.  However, not a great deal is known about Pachycephalosaurus and other bone-headed dinosaurs.  Fossil remains tend to be very fragmentary and most species have been named from quite scrappy remains and then you have those amazing skulls to consider.

The CollectA Pachycephalosaurus Dinosaur Model

CollectA Pachycephalosaurus model.

A lithe Pachycephalosaurus dinosaur model.  Pachycephalosaurus (P. wyomingensis) is the largest known member of the Pachycephalosauridae with an estimated body length of 4.6 metres.

Picture Credit: Everything Dinosaur

Several species have been named based on the shape and cranial ornamentation associated with those thickened skulls.  The thick bone may resist erosion and provide palaeontologists with some fossil bone to study, but it has been suggested that the skulls of these dinosaurs changed dramatically as the animal grew.  So much so in fact, that a number of academics, including Mark Goodwin, have published scientific papers that cast doubt on the validity of many Pachycephalosaur species.  For example, palaeontologists such as Goodwin have put forward evidence to suggest that both Dracorex and Stygimoloch are not distinctive species, the fossils ascribed to these two genera could represent juvenile Pachycephalosaurus specimens.

It seems, just like many other types of Late Cretaceous Ornithischian dinosaur, the Pachycephalosaurs underwent extreme changes to the shape of their heads as they grew up.  Such changes in cranial morphology have resulted in the establishment of several species that may actually just represent examples of the same species but at different growth stages.

Some Palaeontologists Suggest that Radical Changes in Skull Shape and Ornamentation Do Not Indicate Different Species but Different Growth Stages

Different skull shapes and ornamentation linked to different growth stages.

It has been proposed that the cranial ornamentation and skull shape of Pachycephalosaurs changed as these animals grew and matured. This can cause confusion when trying to identify species.

Picture Credit: Kari Scannella with additional annotation by Everything Dinosaur

To complicate matters, Pachycephalosaur fossil material covers a period of approximately 2 million years.  Over this timescale, these animals evolved and their skull morphology changed, thus, further blurring the lines between different species and fossils of the same species but at different levels of maturation.

Confirming the Likely Diet of Pachycephalosaurus

It would be difficult to confirm that Pachycephalosaurus also ate other animals as well as plants, but not impossible.  Only one jaw fossil with the front teeth in situ has been found, so scientists don’t know whether the diets of these dinosaurs changed as they grew.  Perhaps, young Pachycephalosaurs were omnivorous, whilst when fully grown, adults tended to consume plants rather than other animals.  The rib cages of those genera which have a more complete fossil record, suggest that these bipeds had large guts, this would indicate a digestive system adapted to processing vegetation.  Professor Philip Currie (University of Alberta), who also attended the Society of Vertebrate Palaeontology meeting, has proposed that studying carbon isotopes preserved in the tooth enamel might provide further evidence relating to diet.  In addition, the many hundreds of examples of isolated, broken teeth from the Hell Creek Formation could be re-examined and checked for any potential affinities with the Pachycephalosauridae.  Feeding traces from fossil bone could also yield more data in support of the idea that bone-headed dinosaurs ate meat.

A Reconstruction of the Skull of an Adult Pachycephalosaurus

A replica skull of Pachycephalosaurus wyomingensis.

Pachycephalosaurus wyomingensis replica skull.

Picture Credit: Everything Dinosaur

A spokesperson from Everything Dinosaur commented:

“It is likely that there are many more examples of Pachycephalosaurs to be found in Upper Cretaceous rocks, hopefully, if more fossil material can be discovered, then palaeontologists will be able to piece together a more complete phylogeny of these strange dinosaurs.  Furthermore, if more examples of their dentition [teeth] come to light, then we might be able to gain a better understanding of their diets. “

25 10, 2018

Giant Flying Squirrel Redraws Family Tree

By | October 25th, 2018|Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

Flying Squirrel Fossil Sorts Phylogeny

The fossilised remains of a large flying squirrel unearthed at a landfill site in north-eastern Spain (Catalonia), has helped researchers to re-write the family tree of the Sciuridae family.  Estimated to have been around one metre in length (including tail) and weighing up to 1.6 kilograms, the newly described squirrel species named Miopetaurista neogrivensis is around the size of the largest flying squirrels today, the Chinese giant flying squirrel (Petaurista alborufus).  Its fossils show that the flying squirrel body plan has not changed for millions of years.

A Life Reconstruction of the Newly Described Miopetaurista neogrivensis (Middle-Late Miocene of Europe)

Miopetaurista neogrivensis illustrated.

A life reconstruction of the giant prehistoric squirrel Miopetaurista neogrivensis.

Picture Credit: Óscar Sanisidro

Mistaken for a Primate

The fossils, including most of the skull and jaws from a single individual, were discovered in 2002, when alterations were being made to the landfill site.  At first, it was thought that the long, thin bones represented a primate, as simian fossils are known from these Miocene-aged deposits.

One of the authors of the scientific paper, published in the journal eLife, Óscar Sanisidro (University of Kansas Biodiversity Institute and Natural History Museum), takes up the story:

“That area is very rich in fossils.  The recovered specimen was unearthed by an excavator machine while digging up a sector of the landfill.  They could only see a couple of bones poking out from the debris.  They thought it might be a species of primate because of its limb proportions, maybe Pliopithecus, a small monkey found in the area.  Additionally, the presence of a lot of early hominoids in the nearby deposits posed it as an excellent place to look for those animals.”

Once the block of stone containing the fossil material had been removed and work had started to clean and prepare the bones, it soon became clear that the fossils represented a super-sized rodent.  The key to identifying the specimen as a flying squirrel came in the discovery of the specialised wrist bones (pisiforms) which are unique to flying squirrels.  These bones attach to a spur of cartilage that supports the skin membrane (patagium), that allows these arboreal specialists to glide.  Once a pisiform bone had been identified in the specimen, it became clear to the research team that these fossils represented a flying squirrel.  The fossils, dated to approximately 11.6 million years ago (Serravallian to Tortonian faunal stage of the Middle to Late Miocene), are very similar to the skeletons of living flying squirrels.  Miopetaurista neogrivensis, is the oldest flying squirrel fossil found to date that has a modern-looking anatomy and it shows that these mammals have remained almost unchanged for nearly 12 million years.

Views of the Fossilised Bones and Teeth of the Newly Described Miocene Flying Squirrel M. neogrivensis

Miopetaurista fossils.

The fossilised bones and teeth of the Miocene flying squirrel Miopetaurista.

Picture Credit: Óscar Sanisidro

Redrawing the Evolutionary Family Tree of the Sciuridae

This Spanish fossil discovery has helped palaeontologists to redraw the evolutionary tree of the squirrel family.  That branch of the Sciuridae that led to modern flying squirrels must have diverged many millions of years earlier than previously thought.  This spilt is now believed to have occurred sometime between 31 and 25 million years ago.

The Phylogeny of the Flying Squirrels – M. neogrivensis Helps to Redraw the Squirrel Family Tree

 

Flying squirrel phylogeny.

The phylogeny of the flying squirrels has been revised after the description of Miopetaurista neogrivensis.

Picture Credit: eLife

The researchers identified Miopetaurista neogrivensis as sister taxon of the living Petaurista taxon following an in-depth Bayesian statistical analysis that looked at over 100 anatomical characteristics in 38 taxa.  The team were also able to plot key periods in the evolution of these mammals and link them to incidences of environment and climate change such as the mid-Miocene climate optimum (global warming) and the onset of Arctic glaciation (global cooling).

Commenting on the significance of the fossils and their impact on squirrel phylogeny,  Óscar Sanisidro stated:

“When working with tree squirrels and flying squirrels, some of the features we thought were unique to flying squirrels have been found by our team in some non-flying squirrels.  Right now, we don’t have features unique to flying squirrels except for the wrist.  With fossils of micromammals, ninety-nine percent of the time you’re working with teeth.  Wrist bones are extremely rare.  But now we can link those traits to the postcranial skeleton.  Some of the flying squirrels found in the past might not be flying squirrels because they might have had features common to other groups.”

Well-adapted to a Forest Environment

Flying squirrels today are globally distributed, but most species are found in Asia.  It is likely that, just like its extant descendants, Miopetaurista neogrivensis was probably nocturnal and very much at home in its sub-tropical forest environment.  It is not known what this ancient flying squirrel ate, today’s flying squirrels have a variety of feeding behaviours, however, Miopetaurista was probably omnivorous, feeding on nuts, fruit and insects.

Spain in the Mid Miocene – A Sub-tropical Forest Environment

The Middle Miocene - sub-tropical forests across much of Europe.

Spain in the Middle Miocene.

Picture Credit: Óscar Sanisidro

23 10, 2018

Breathing Life into the Bird Lungs Debate

By | October 23rd, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Photos/Pictures of Fossils|0 Comments

Archaeorhynchus spathula – Lungs in an Ancient Bird Fossil?

Modern birds have a very efficient respiratory system.  Their lungs are much more efficacious than those of mammals.  However, scientists are not sure when and how this breathing system evolved.  It has been suggested that the origins of the bird’s respiratory system, complete with air sacs and the ability to stop de-oxygenated air mixing with oxygenated air as it is expelled from the lungs, is one anatomical trait inherited from their dinosaur ancestors.  Writing in the academic journal the “Proceedings of the National Academy of Sciences”, a group of international scientists claim that the fossilised remains of an Early Cretaceous bird breathes new life into the evolution of the bird lungs debate.

The Main Slab Showing the Archaeorhynchus spathula Specimen

Archaeorhynchus spathula fossil (main slab).

The main slab showing the fifth specimen of Archaeorhynchus spathula to have been described. Palaeontologists have identified what might be evidence for avian lungs as well as a pintail on this ancient bird.

Picture Credit: J. Zhang/Institute of Vertebrate Palaeontology and Palaeoanthropology (IVPP)

The Fifth Specimen of Archaeorhynchus spathula to be Described

A study of the slab and counter slab representing the fossilised remains of a prehistoric bird (Archaeorhynchus spathula), suggests that, in this remarkably complete specimen, remnants of the animal’s soft tissues including internal organs such as the lungs could have been preserved.  Using scanning electron microscopy, the research team, including members of the Beijing based, Institute of Vertebrate Palaeontology and Palaeoanthropology (IVPP), identified what could be evidence of paired lungs.  The structures identified by the team suggest that Archaeorhynchus had a respiratory system capable of handling the large amount of oxygen required to sustain powered flight.  Although, the conclusions drawn in the scientific paper have been questioned by several academics, if these are lungs, then it indicates that physiological adaptations in Aves came before changes in their skeleton during the evolution of anatomically modern birds.

The Scientists Identified What Could be Paired Lungs on the Counter Slab of the Fossil Specimen

Archaeorhynchus spathula counter slab with possible lung preservation.

Counter slab of Archaeorhynchus spathula specimen interpreted as having lung preservation.  The dotted outlines mark the location of organs (paired lungs and the stomach).

Picture Credit: X Wang et al (PNAS)

The Significance of this Research

Archaeorhynchus spathula is one of a number of bird genera known from the Lower Cretaceous Jiufotang Formation (China).  Copious amounts of gizzard stones associated with this and the previous specimens suggest that these primitive birds were probably vegetarian.  They form part of a rich prehistoric fauna known as the Jehol Biota.  In total, five specimens have been described to date but this fossil, consisting of a crushed specimen represented by a slab and counter slab, is the most complete.  Numerous feathers and traces of plumage can be made out and the researchers report that Archaeorhynchus had a pintail, a feature previously not seen in Mesozoic birds.  A. spathula has been classified as a basal member of the Ornithuromorpha, a group distantly related to today’s birds and one that possessed a mix of ancient and more modern anatomical features.

This fascinating fossil described as looking something like “road kill” by one observer, might have allowed palaeontologists to catch a glimpse of a stage of bird evolution where an advanced pulmonary system had evolved yet the skeleton lacked the adaptations seen in extant birds to permit efficient powered flight.

For an article published in 2007 that examined the respiration of dinosaurs: Study Indicates that Dinosaurs were Super-efficient Breathers

21 10, 2018

Flea Bites and Dermal Infections in Glyptodonts

By | October 21st, 2018|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|2 Comments

Fleas on Glyptodonts

A new study examining one of the more bizarre types of megafauna from prehistoric South America has revealed that glyptodonts and their relatives suffered from fleas and dermal infections.  It seems that the hard, bony armour of some of these car-sized giants was no defence against flea bites.  Brazilian-based scientists writing in the open access, on-line journal “PLOS One”, have studied hundreds of pieces of glyptodont armour and discovered evidence of infections caused by fleas.

Such armour might have deterred a sabre-toothed cat from attacking, but the osteoderms and armoured tails were no defence against parasites.

A Skeleton of the Giant Glyptodont Panochthus spp.

Fossil glyptodont Panochthus.

A glyptodont fossil (Panochthus frenzelianus).  Researchers studied the tiles of bone (osteoderms) that formed the protective bony exoskeletons of extinct types of armadillo and determined that these armoured giants suffered from parasites and skin infections.

Picture Credit: R. Somma/Wikimedia Commons

Extinct Members of the Order Cingulata Studied

The scientists from Universidade Federal Rural do Semi-Árido, Mossoró (Brazil), studied the osteoderms that make up the exoskeleton of two extinct genera of glyptodonts Panochthus (pictured above) and Glyptotherium.  In addition, the research team examined the fossilised armour of another extinct armadillo-like creature Pachyarmatherium.  All these mammals belong to the Order Cingulata (armadillos and their relatives).  Damaged osteoderms were noted in all three genera and attributed to attacks by fleas and infections.  The scientists were able to identify the flea bites as coming from one particular genus  – Tunga.  The Tunga flea, sometimes referred to as the “jigger flea”, is native to South and Central America and is known to parasitise a number of large mammals including humans.  The bites cause well-defined circular lesions and perforations.  Such patterning was identified in a number of fossilised pieces of dermal armour.

Flea bites permitted secondary damage to be caused by the invasion of pathogenic microorganisms such as bacteria and fungi.

The External Surface of Osteoderms from the Glyptodont Glyptotherium Showing Pitting and Damage

Cingulata osteoderm parasite infection.

Osteoderms of the Brazilian glyptodont Glyptotherium showing damage from flea bites.

Picture Credit: PLOS One

The picture (above) shows severe pitting (black arrows) in (A) and three other osteoderms attributed to Glyptotherium which show stages of damage from (B), slight, through to (D) advanced pitting and the response to the damage by the deposition of more bone (calcium deposition).  The scale bar in A = 3 cm, whereas, the scale bar in B-D is 4 cm.

A Life Reconstruction of the Brazilian Glyptodont Glyptotherium

Glyptotherium life reconstruction.

A life reconstruction of the giant South American glyptodont Glyptotherium.

Picture Credit: Larjard/Wikimedia Commons

The bone alteration and re-growth identified in this study represent the first record of flea attack and pitting in two genera of large glyptodonts Panochthus and Glyptotherium and in a non-glyptodontid, large cingulate (Pachyarmatherium), from the Quaternary of the Brazilian Intertropical Region.  These newly identified flea bite occurrences and subsequent infections widen the geographic distribution of those diseases during the Cenozoic and provide more evidence for the co-evolution of parasites such as the Tunga flea and South American megafauna.

The scientific paper: “Ectoparasitism and Infections in the Exoskeleton of Large Fossil Cingulates” by Fábio Cunha Guimarães de Lima, Kleberson de Oliveira Porpino published in PLOS One

19 10, 2018

Feeding Traces on the Frill of a Young Centrosaurus

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

Bite Marks Found on the Frill of a Young Centrosaurus

The movies and television documentaries featuring dinosaurs are stuffed full of them, but the fossil record tells a different story.  What are we referring to?  Dinosaurs hunting, attacking and fighting other dinosaurs.  Rarely has a programme or film been produced about the Dinosauria that does not feature some gory scenes of a bloody battle or a fearsome Theropod feasting on some poor, unfortunate plant-eating victim.  However, although such interactions obviously took place, the fossil record demonstrating such behaviour is extremely sparse.  A new paper, published in the open access journal “PeerJ”, reports on the discovery of bite marks preserved on the frill of a young Centrosaurus.

This raises two intriguing questions:

  • Which meat-eating dinosaur made the bite marks?
  • Is this evidence of predation or scavenging a carcass?

Dinosaurs Fighting – A Tyrannosaur Attacks a Horned Dinosaur (Styracosaurus)

Daspletosaurus fighting a horned dinosaur.

Tyrannosaur fighting a horned dinosaur.

Picture Credit: John Gurche

Bite Marks – Tell-Tale Signs of Predator/Prey Interaction

Bite marks on fossil bones can provide valuable information about interactions between carnivorous dinosaurs and the animals that they attacked.  It is not always possible to distinguish whether the trace fossils represent wounds inflicted on an animal during a fight, or whether these marks represent post-mortem feeding, such as consumption of the victim.  If there are signs of healing and bone growth, palaeontologists can be confident that the bite marks in that instance represent a lucky escape for the intended victim.  The key thing to note, is that the more data about bite marks that can be collected, the better the dataset that palaeontologists have to compare potential bite mark injuries against.

Part of the Skull of a Juvenile Centrosaurus With Tooth-marks

Ironically, quite a large proportion of the tooth-mark fossils associated with dinosaurs come from those deposits that are associated with the remains of large-bodied tyrannosaurids.  In this newly published paper, the scientists from Queen Mary University London and the Royal Tyrrell Museum (Alberta, Canada), report on the discovery of a portion of the skull from a juvenile horned dinosaur.  The bone, a fragment of the squamosal, which makes up part of the frill, was found on the surface of a dinosaur bonebed in the Dinosaur Provincial Park Formation.  The fossil is approximately 76.3 to 75.6 million years old and has been assigned to the horned dinosaur species Centrosaurus apertus.

Views of the Fragment of the Squamosal Bone (Centrosaurus apertus) and Line Drawings

Identifying potential bite marks in a bone from a juvenile Centosaurus.

The two sides of the partial squamosal bone from a juvenile Centrosaurus showing signs of damage/wear/bite marks. Actual fossil (A and B), interpretive line drawings (A1 and B1).

Picture Credit: PeerJ with additional annotation by Everything Dinosaur

Key

BM = Probable bite marks

? = Possible bite marks

Analysis of the fossil found numerous marks and gouges on both sides of the fossil bone.  Some of these marks could have resulted from damage due to transportation prior to burial.  Other marks could reflect effects caused by chemical erosion or the presence of vascular grooves.  However, the scientists were able to propose that at least some of the marks were due to teeth coming into contact with the bone.

The Position of the Partial Squamosal on the Skull of a Juvenile Centrosaurus and an Adult Skull Shown for Comparison

Juvenile (A) and adult (B) Centrosaurus skulls.

A comparison of Centrosaurus skulls (C. apertus) Juvenile (A) and adult (B).  The squamosal bone that makes up part of the frill is shaded grey, whilst the portion of bone in the study is shaded dark grey.

Picture Credit: PeerJ

Although it is difficult to assess the size of the horned dinosaur based on such a small fragment of bone, the scientists suggest that based on comparisons with squamosal bones from adults, the juvenile Centrosaurus was perhaps about a third the size of a fully grown Centrosaurus.

Which Dinosaur Made the Feeding Traces?

The researchers ruled out crocodiles, other reptiles and mammals when it came to identifying what creature made the bite marks.  This left the team with three types of Theropod dinosaur to investigate.  Troodontids, Dromaeosaurs and Tyrannosaurs are known from the Dinosaur Provincial Park Formation.  There is also the genus Richardoestesia to consider, its affinity within the Theropoda is uncertain.  The bite marks are too small to have been made by a large Tyrannosaur, but a juvenile Tyrannosaur might have scavenged the carcass.  It is also possible that a dromaeosaurid may have fed on the remains as well.  It is possible that both the dromaeosaurid and a young Tyrannosaur fed on the carcass, after all, modern carcasses may be fed on by multiple species (lions may kill a zebra but hyenas may chase them off the kill and rob them of the carcass – kleptoparasitism).

To read an article from Everything Dinosaur published in 2015 that looks at the structure of the teeth of different Theropod dinosaurs: Research to get your Teeth into

A Hypothesised Reconstruction of a Juvenile Gorgosaurus Feeding on the Carcass of a Juvenile Centrosaurus

A speculative illustration of a young Gorgosaurus feeding on the carcass of a juvenile Centrosaurus.

A young Tyrannosaur (Gorgosaurus) scavenging the carcass of the juvenile Centrosaurus.

Picture Credit: Marie-Hélène Trudel-Aubry/PeerJ

Slim Pickings

The marks on the squamosal fragment represent the first documented case of a carnivore consuming a juvenile ceratopsid, but the trace fossils may represent scavenging a corpse rather than predation.  However, there is not a lot of meat on a squamosal bone.  The scientists suggest that the feeding marks represent late stage consumption, as the most nutritious parts of the young Centrosaurus had already been eaten.  It is possible that a large Tyrannosaur made the kill, fed and then abandoned the carcase which was later picked over by other Theropods.

Despite the apparent preferences for feeding on juvenile dinosaurs, most feeding traces described to date are on the bones of adults which may have resisted being consumed and destroyed (even by large Tyrannosaurs).  Feeding traces on a juvenile dinosaur remain unusual and exceptionally rare.  Perhaps the size and shape of Ceratopsian skulls, even in juveniles, made them difficult to process or required an excess of handling effort for a relatively little reward in terms of food.

The scientific paper: “Bite Marks on the Frill of a Juvenile Centrosaurus from the Late Cretaceous Dinosaur Provincial Park Formation, Alberta, Canada” by David W.E. Hone, Darren H. Tanke and Caleb M. Brown published in PeerJ

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