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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.

29 01, 2020

Noasaurids from Down Under

By | January 29th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Australia’s Latest Theropod Dinosaur

The theropod fossil record for Australia is particularly poor.  The majority of the meat-eating dinosaur fossils found down-under come from the Albian-Cenomanian faunal stages of the Cretaceous have been predominantly referred to the Megaraptoridae.  However, a single neck bone (cervical vertebra), found in an opal mine near the town of Lightning Ridge (New South Wales), in conjunction with a fragmentary ankle bone from the Gippsland Basin in Victoria have led scientists to conclude that another type of predatory dinosaur roamed Australia – noasaurids.

A Silhouette of the Unnamed Noasaurid with a Human Figure for Scale and the Fossil Neck Bone Placed in Life Position

Fossil neck bone and silhouette showing life position.

Silhouette showing approximate size of the Australian noasaurid and the fossil material.

Picture credit: Tom Brougham (University of New England, New South Wales)

Classifying the Noasauridae

The Noasauridae are a family of small-bodied, fast-running, largely predatory dinosaurs nested within the Superfamly Abelisauroidea, although their exact taxonomic position and which genera fit within the Noasauridae remains controversial.  Essentially, these types of dinosaurs are distantly related to the abelisaurids such as Carnotaurus and Rajasaurus.  Noasaurids demonstrate a wide range of anatomical characteristics.  For example, Masiakasaurus (M. knopfleri), known from the Late Cretaceous of Madagascar, had a downturned lower jaw with teeth in both jaws, whereas the adult forms of Limusaurus (L. inextricabilis) known from the Jurassic of China, had no teeth in their jaws and could have been herbivores.

A Scale Drawing of Masiakasaurus (M. knopfleri)

Masiakasaurus scale drawing.

Unusual theropod dinosaur – Masiakasaurus, the downward turned lower jaw and the dentition suggest that this predator could have specialised in catching fish (piscivore).

Picture Credit: Everything Dinosaur

The Noasauridae are known from the southern hemisphere and seem to have been confined to the landmass of Gondwana.

Dr Tom Brougham (University New England, New South Wales), one of the co-authors of the study, published in the journal Scientific Reports stated:

“It was assumed that noasaurids must have lived in Australia because their fossils have been found on other southern continents that, like Australia, were once part of the Gondwanan supercontinent.  These recent fossil finds demonstrate for the first time that noasaurids once roamed across Australia.  Discoveries of theropods are rare in Australia, so every little find we make reveals important details about our unique dinosaur fauna.”

To read more about Limusaurus: Limusaurus – A Dinosaur That Lost its Teeth as it Grew.

The partial cervical vertebra from the Wallangulla Sandstone Member of the Griman Formation, collected from an underground opal mine at the “Sheepyard” opal field, southwest of Lightning Ridge was found within a bonebed containing the iguanodontian Fostoria dhimbangunmal.  The bone is estimated to be around 100 million years old.  Although, the fossil (specimen number LRF 3050.AR), is badly eroded the researchers discovered that is resembled cervical vertebrae associated with the noasaurids, hence the diagnosis that this fossil indicates the presence of these types of theropod dinosaurs in Australia.

The Neck Bone from the Opal Mine Ascribed to the Noasauridae

Opal mine noasaurid neck bone.

The noasaurid cervical vertebra LRF 3050.AR in (a) ventral; (b) dorsal, (c) left lateral, (d) right lateral, (e) anterior and (f) posterior views.  Note scale bar = 50 mm.

Picture Credit: Brougham et al (Scientific Reports)

The scientists re-examined a ceratosaurian astragalocalcaneum fossil (NMV P221202) that had been found in 2012 in strata associated with the much older upper Barremian–lower Aptian San Remo Member of the upper Strzelecki group in Victoria.  It was concluded that this ankle bone also represented noasaurid fossil material.

The East Gippsland Ankle Bone Now Ascribed to the Noasauridae

East Gippsland astragalocalcaneum (NMV P221202).

The East Gippsland astragalocalcaneum (NMV P221202) in (a) anterior, (b) posterior, and (c) proximal views.  Note scale bar = 20 mm.  This fossil lends support to the idea that noasaurids were present in Australia.

Picture Credit: Brougham et al (Scientific Reports)

Oldest Known Noasaurid

Between them, the Lightning Ridge neck bone and the ankle bone from Victoria represent the first evidence of noasaurid dinosaurs found in Australia.  The astragalocalcaneum material comes from deposits that were laid down in the Early Cretaceous and could be 120 million years of age.  This would make the ankle bone the earliest known example of a noasaurid in the world described to date.  The recognition of Australian noasaurids further indicates a more widespread Gondwanan distribution of the clade outside of South America, Madagascar and India consistent with the timing of the fragmentation of the supercontinent.

The scientific paper: “Noasaurids are a component of the Australian ‘mid’-Cretaceous theropod fauna” by Tom Brougham, Elizabeth T. Smith and Phil R. Bell published in Scientific Reports.

27 01, 2020

A New Species of Allosaurus – Allosaurus jimmadseni

By | January 27th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

“Big Al” is Not Allosaurus fragilis but Allosaurus jimmadseni

A new species of North American Allosaurus has been described, the new dinosaur has been named Allosaurus jimmadseni, the species name honouring the late James H. Madsen Jr, Utah’s first state palaeontologist, who dedicated his career to excavating, preserving and studying the fossils found at the famous Cleveland-Lloyd Dinosaur Quarry.  In 1976, Madsen published a detailed monograph documenting the Allosaurus specimens found at this location, which is now the Jurassic National Monument complete with visitor centre.  The monograph describing and illustrating the Quarry’s Allosaurus fossils is regarded as a seminal piece of work that strongly influenced the direction of research into theropod dinosaurs.

A Pack of Allosaurs (Allosaurus jimmadseni) Attacking a Juvenile Sauropod

A pack of allosaurs (A. jimmadseni) attacking a juvenile sauropod.

Picture Credit: Todd Marshall

“The Ballard of Big Al” – Allosaurus jimmadseni

Fans of the documentary “The Ballard of Big Al”, a spin-off programme to the famous “Walking with Dinosaurs” television series, made by the BBC Natural History Unit and Impossible Pictures that first aired over twenty years ago, will remember that this programme told the story of the life of an Allosaurus.  The fossil specimen used as the basis for the story line, was found in the Howe Quarry (Wyoming), specimen number MOR 693.  This was thought to represent an Allosaurus fragilis, but MOR 693 “Big Al” has now been assigned to this new species.

The Star of the Ballard of Big Al (MOR 693) Now Assigned to A. jimmadseni

"The Ballard of Big Al".

The front cover of “The Ballard of Big Al” BBC/Impossible Pictures documentary.  Once thought to be an example of Allosaurus fragilis, this fossil specimen (MOR 693), has been reassigned to A. jimmadseni.

Picture Credit: Everything Dinosaur

New Allosaurus Species Based on Two Nearly Complete Fossil Skeletons

Writing in the academic journal PeerJ, the two authors of the scientific paper Mark Loewen, research associate at the Natural History Museum of Utah and associate professor in the Department of Geology and Geophysics at the University of Utah and co-worker Dan Chure, now retired, but formerly based at the Dinosaur National Monument, set out the case for the erection of a new species of Allosaurus.  Between them they have studied virtually all the Allosaurus specimens in North American museums, a research project that has taken two decades and is still on-going.  The paper describing Allosaurus jimmadseni, is one of several papers that will be published by the pair.  Future scientific papers will address post-cranial morphology and provide a further revision of the Allosaurus genus.

The new species of Allosaurus has been established based on the study of the “Big Al” specimen and specimen number DINO 11541 discovered by Dr George Engelmann (University of Nebraska), in 1990.  Excavation continued at the Dinosaur National Monument site for several years, gradually exposing an almost complete articulated skeleton, but missing the skull.  In the summer of 1996, University of Utah employee Ray Jones returned to the site and used a gamma X-ray detection device to locate the beautifully preserved cranium.

A Cast of the Specimen DINO 11541 Showing the Articulation and the Approximate position of the Skull

Painted cast of Allosaurus jimmadseni holotype material.

A painted cast of the holotype fossil material DINO 11541 (Allosaurus jimmadseni).

Picture Credit: Dan Chure

Three Recognised Allosaurus Species

Since Allosaurus was first erected by the American palaeontologist Othniel Charles Marsh in 1877, numerous species have been named.  However, in this research paper only three species are recognised – Allosaurus fragilis and Allosaurus jimmadseni in North America and Allosaurus europaeus from Europe.  The researchers identified a number of unique characteristics (autapomorphies), in the specimens MOR 693 and DINO 11541 that led them to propose a new species.  For example, the paired nasals of A. jimmadseni possess bilateral, thin, blade-like crests that run from the nostrils up the snout, ending at the apex of the eye socket.  This feature is absent in Allosaurus fragilis.

A Life Reconstruction of Allosaurus jimmadseni

Allosaurus jimmadseni life reconstruction.

A reconstruction of the head of Allosaurus jimmadseni.  Note the pair of bilateral nasal crests that run from the nostrils to the eye socket.  This feature is absent in Allosaurus fragilis.

Picture Credit: Andrey Atuchin

As a result of this new study, a number of other fossil specimens formerly placed within A. fragilis have been reassigned to A. jimmadseni.

Geologically the Oldest Species of Allosaurus

The “Big Al” fossil and specimen number DINO 11541 come from strata associated with the Lower Morrison Formation (Brushy Basin Member and Salt Wash Member respectively), as such, these animals are several million years older than those fossils now ascribed to Allosaurus fragilis.

Commenting on the significance of their extensive research, co-author Mark Loewen stated:

“Previously, palaeontologist thought there was only one species of Allosaurus in Jurassic North America, but this study shows that there were two species.  The newly described Allosaurus jimmadseni evolved at least five million years earlier than its younger cousin, Allosaurus fragilis.  The skull of Allosaurus jimmadseni is more lightly built than its later relative Allosaurus fragilis, suggesting a different feeding behaviour between the two.”

Comparing Allosaurus Skulls (Three Species Compared)

Comparing Allosaurus skulls.

Comparing the skulls of Allosaurus species (left lateral view).  (A) Allosaurus fragilis (DINO 2560).  (B) Allosaurus jimmadseni (DINO 11541).  (C) Allosaurus europaeus (ML 415).  Scale bars equal 10 cm.

Picture Credit: Chure and Loewen published in PeerJ

An Anagenetic Lineage?

This study suggests that Allosaurus jimmadseni fossils are found in the Salt Wash Member of the Morrison Formation in Utah and the lower part of the Brushy Basin Member of the Morrison Formation in Wyoming and South Dakota.  If this is the case, then it raises the question whether the later A. fragilis evolved from the earlier Allosaurus jimmadseni.  Did Allosaurus fragilis directly evolve from its older, close relative?  If it did, then this is a form of evolution known as anagenesis – whereby one species gradually evolves into a new species over a long period of geological time.  An anagenetic lineage occurs when one population representing a single species, over thousands and thousands of years, gradually accumulates change.  These changes eventually become sufficiently distinct from the earlier form that descendants can be labelled a new species.

Skull Drawings and Skeletal Reconstructions of Allosaurus jimmadseni

Skull and skeletal diagrams Allosaurus jimmadseni.

Skull and skeletal reconstructions of Allosaurus jimmadseni.

Picture Credit: Chure and Loewen published in PeerJ with additional notation by Everything Dinosaur.

The illustration above shows stylised line drawings of the skull of Allosaurus jimmadseni in lateral, dorsal and posterior views along with skeletal reconstructions of DINO 11541 and “Big Al”.  Scale bar (A-C) equals 10 cm and for D-E 1 metre.

Allosaurus, as the most common genus of Late Jurassic theropod in North America has played a significant role in helping palaeontologists to cement the phylogeny of Jurassic meat-eating dinosaurs. A revision of this key genus will probably have important consequences for future studies regarding the taxonomy of the Coelurosauria.

The scientific paper: “Cranial anatomy of Allosaurus jimmadseni, a new species from the lower part of the Morrison Formation (Upper Jurassic) of Western North America” by Daniel J. Chure and Mark A. Loewen published in PeerJ.

25 01, 2020

Canada’s Newest and Oldest Tyrannosaurid – Thanatotheristes degrootorum

By | January 25th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|1 Comment

Canada’s Newest and Oldest Tyrannosaurid – Thanatotheristes degrootorum

Researchers from the University of Calgary and the Royal Tyrrell Museum (Alberta, Canada), have published a scientific paper describing a new species of tyrannosaur, based on fragmentary skull and jaw elements excavated from Campanian-aged deposits representing the Foremost Formation of Alberta. The Foremost Formation is the oldest geological formation ascribed to the Belly River Group, it is overlain by the Oldman Formation and the Dinosaur Park Formation. The newly named tyrannosaurid is Thanatotheristes degrootorum and its fossilised remains represent the earliest known evidence of diagnostic tyrannosaurid material to have been discovered in Canada.

A Silhouette of the Skull of Thanatotheristes degrootorum

Thanatotheristes skull reconstruction.

Thanatotheristes skull reconstruction showing known fossil material.

Picture Credit: Science Direct/The Journal of Cretaceous Research

The Evolution of North American Tyrannosaurs

Whilst tyrannosaurid fossil material is synonymous with Upper Campanian and Maastrichtian-aged deposits in North America, very little tyrannosaur fossil material has been recovered from older Campanian deposits.  In the autumn of 2018, Everything Dinosaur published an article on a new species of tyrannosaurid (Dynamoterror dynastes), which had been found in Lower to Mid Campanian-aged deposits in New Mexico.  Prior to the discovery of Dynamoterror, the fossil record for these types of theropods had been largely restricted to a period from approximately 77 million years ago to the K-Pg extinction event.  Dynamoterror roamed southern Laramidia around 80 million years ago, the fossils associated with T. degrootorum are roughly contemporaneous (dated from 80.1 to 79.5 million years ago).  Together, the northern Thanatotheristes and the southern Dynamoterror will help scientists to better understand tyrannosaurid evolution in North America.

To read our article about Dynamoterror dynastesPowerful Terror Ruler Dynamoterror dynastes.

A Sister Taxon to Daspletosaurus spp.

The researchers, which included Darla Zelenitsky (University of Calgary) and Caleb Brown (Royal Tyrrell Museum of Palaeontology), define Thanatotheristes as the sister taxon to the later tyrannosaurid genus Daspletosaurus.  Together, these taxa provide evidence for the existence of a clade of long and deep-snouted tyrannosaurines endemic to northern Laramidia during the Campanian.  The clade has been named the Daspletosaurini and comprises Thanatotheristes (pronounced Than-ah-toe-ther-ris-tees) and the two known species of Daspletosaurus.  D. torosus is associated with the Oldman and Dinosaur Park Formations of Alberta, whilst the recently described (2017), Daspletosaurus horneri  is from the uppermost parts of the geologically slightly younger, Two Medicine Formation of Montana.  Other proposed Daspletosaurus material is awaiting scientific description, so it is probable that additional species may be added to the Daspletosaurus genus.

The scientists conclude that the Tyrannosauridae family in North America consisted of several geographically segregated clades rather than a series of monogeneric (a genus with just one species in it), successive sister taxa as postulated in previous studies.

The Stratigraphy of the Belly River Group Showing Approximate Locations in Geological Time of Described Daspletosaurini

The Stratigraphy of the Belly River Group.

The stratigraphy of the Belly River Group with approximate position of Thanatotheristes and Daspletosaurus spp. fossil finds.

Picture Credit: Everything Dinosaur from D. Eberth (Dinosaur Provincial Park)

The figure (above) shows the stratigraphy of the Belly River Group and its component formations.  The theropod shape (red) shows the approximate chronological location of the Thanatotheristes degrootorum fossil material, whilst the blue theropod silhouettes represent the approximate chronological location of Daspletosaurus fossil material.  The black star shape represents the approximate age of Daspletosaurus horneri fossil material from the Two Medicine Formation.

It can be speculated that geographically dispersed but temporally contemporaneous genera such as Daspletosaurus and Thanatotheristes adds support to the theory that distinct regional faunas evolved on Laramidia during the Late Cretaceous.  There may have been physical barriers that prevented the mixing of faunas on this landmass, this led to provincial ecosystems, with different parts of Laramidia having different types of dinosaur associated with them.

The skull of Thanatotheristes degrootorum is estimated to have measured around 80 cm in length, but the actual size of this dinosaur is uncertain as the fossils probably represent a sub-adult.

The scientific paper: “A new tyrannosaurine (Theropoda:Tyrannosauridae) from the Campanian Foremost Formation of Alberta, Canada, provides insight into the evolution and biogeography of tyrannosaurids” by Jared T. Voris, François Therrien, Darla K. Zelenitsky, and Caleb M. Brown published in the Journal of Cretaceous Research.

21 01, 2020

The Dogged “Dogbane” Family of Plants

By | January 21st, 2020|Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

Earliest Fossil Record of Asclepiadoideae (Dogbane Family) Reported from Asia

Scientists from the Chinese Academy of Sciences, writing in the academic journal “The American Journal of Botany”, have reported the earliest fossil record of the Apocynaceae family of plants from fossils found on the Central Qinghai‐Tibetan Plateau.  These flowering plants are often referred to as the “Dogbane” family, as many species have poisonous sap and this was used to keep dogs at bay.

The fossils representing preserved seeds collected from an altitude of around 4,800 metres indicate that during the Early Eocene, this part of Asia had a very much warmer subtropical climate.  Based on the seed fossils the researchers discovered, the scientists have been able to erect a new genus (Asclepiadospermum) and place two new species of Early Eocene plants within it (A. marginatum and A. ellipticum)

Fossilised Seeds of One of the Newly Described “Dogbane” Species Asclepiadospermum marginatum

Asclepiadospermum marginatum fossil seeds from Tibet.

Asclepiadospermum marginatum fossil seeds from a Tibetan plateau.

Picture Credit: Cédric Del Rio et al (The American Journal of Botany)

Asclepiadoideae is now geographically widespread, found tropical and subtropical regions around the world with something like 5,000 individual species recorded, ranging in size from trees to small shrubs and climbing vines.  Fossilised remains of these types of plants from the Neogene of Europe and North America are relatively abundant, but fossils from Asia are exceptionally rare.  The researchers studied three Apocynaceae seed impressions from the Lower Eocene Niubao Formation, Jianglang village, Bangor County on the central Qinghai‐Tibetan Plateau.  The fossilised remains are more than fifty million years old.

A Record of a Subtropical Ecosystem

After comparing with modern seeds and mapping of the seed characters on a phylogeny of the family Apocynaceae, the researchers recognised the fossils as part of the subfamily Asclepiadoideae and erected the new genus with its two species of prehistoric plants.  The Jianglang location is now situated at an altitude of approximately 4,800 metres above sea level and hosts cold alpine vegetation dominated by grassland.  However, these fossils indicate that the early Eocene climate and biodiversity were profoundly different.  Asclepiadoideae is now present in Asia and widespread in tropical to subtropical areas.

Commenting on the significance of the seed fossils, Professor SU Tao ( Laboratory of Tropical Forest Ecology, Chinese Academy of Sciences), corresponding author for the research paper, stated:

“The newly discovered early Eocene Asclepiadospermum from the central Qinghai‐Tibetan Plateau clearly belongs to Asclepiadoideae.  Our discoveries thus reconcile the fossil record and molecular estimations and represent the earliest fossil record for the subfamily.  Our fossils are important in documenting the floristic connection between Africa and Eurasia during the Eocene.  Based on current knowledge, Asclepiadospermum could represent an example of early diversification of Apocynaceae in Asia, with subsequent diversification in the Northern Hemisphere.”

19 01, 2020

Little Dancing Dragon Sheds Light on How Dinosaurs Grew Up

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

The New Microraptorine Wulong bohaiensis

A new feathered dinosaur from Liaoning Province (north-eastern China), has been named and described.  The little dinosaur, not much bigger than a crow, but with a long tail, has been named Wulong bohaiensis.  The fossilised feathers associated with the beautifully preserved skeleton, include two long tail feathers, the sort of extravagant plumage associated with mature birds which use such adornments to attract a mate.  However, when an analysis of the limb bones was undertaken to determine the age of the specimen (histological analysis), the research team discovered that the specimen represented a juvenile.

Either those long, showy feathers served some other function, or dinosaurs that were closely related to birds grew up differently when compared to their living relatives.

The Newly Described Wulong bohaiensis.

Wulong bohaiensis fossil specimen.

The beautifully preserved and almost complete W. bohaiensis fossil specimen.

Picture Credit: Ashley W. Poust (University of California)

Dancing Dragon

The fossil specimen was found more than ten years ago by a local farmer.  It had resided in the vertebrate collection of the Dalian Natural History Museum (Liaoning Province), being eventually described and studied by scientists at the museum in conjunction with student Ashley Poust under the supervision of  Dr David Varricchio (Montana State University), her former advisor, prior to Ashley moving to the University of California.

The genus name is Chinese for “dancing dragon”, a reference to the posture of the preserved specimen.  A phylogenetic analysis places W. bohaiensis within Microraptorinae, this little dinosaur was therefore closely related to Microraptor.  Whether, like Microraptor, Wulong bohaiensis was capable of powered flight can be speculated upon.

Ashley Poust explained the significance of this research stating:

“The specimen has feathers on its limbs and tail that we associate with adult birds, but it had other features that made us think it was a juvenile.”

In order to determine the age of the dinosaur when it died, staff at the Dalian Natural History Museum gave permission for the tibia, fibula and humerus bones to be examined histologically.  Essentially, cross-sectional slices of these bones were removed from the skeleton, prepared and then examined under a microscope so that the seasonal/annual growth of the animal could be identified.  Such a technique is invasive and will cause damage to the fossil specimen, fortunately, the curators at the Dalian Natural History Museum took the decision that in order to benefit science the invasive procedures had to be undertaken.

Ashley commented:

“Thankfully, our co-authors at the Dalian Natural History Museum were really forward thinking and allowed us to apply these techniques, not only to Wulong, but also to another dinosaur, a close relative that looked more adult called Sinornithosaurus.”

A Life Reconstruction of Wulong bohaiensis

Life reconstruction of Wulong bohaiensis.

A life reconstruction of Wulong bohaiensis.  The sharp, small teeth in the jaw of Wulong suggest that this dinosaur was a piscivore, or perhaps feeding on insects.

Picture Credit: Ashley Poust (University of California)

Sinornithosaurus Provides a Surprise

The histology of a specimen of another feathered dinosaur associated with the Early Cretaceous Jehol biota was also examined.  The research team wanted to compare their immature, juvenile Wulong to what they thought was a specimen of an adult Sinornithosaurus.  However, analysis of the bone structure of the Sinornithosaurus provided a surprise.  The histology revealed that both specimens were young and still growing at death, indicating an age for Wulong of about one-year-old.

Commenting on the results of the histological analysis on the Sinornithosaurus specimen, Ashley explained:

“Here was an animal that was large and had adult looking bones.  We thought it was going to be mature, but histology proved that idea wrong.  It was older than Wulong, but seems to have been still growing.  Researchers need to be really careful about determining whether a specimen is adult or not.  Until we learn a lot more, histology is really the most dependable way.”

An Illustration of Sinornithosaurus

Sinornithosaurus

The fearsome dromaeosaurid Sinornithosaurus, in reality this dinosaur was about 1-1.2 metres in length, although it might have preyed upon the smaller Wulong bohaiensis.

Picture Credit: Zhao Chuang

This new study suggests that either young dinosaurs developed elaborate tail feathers for some other purpose, or that they were growing feathers in a different way from their close living relatives the Aves (birds).

The Paraves Clade

The Paraves is a clade of theropod dinosaurs.  It is defined as containing all the dinosaurs which are more closely related to birds than to oviraptorosaurs.  As such it includes troodontids, dromaeosaurids and avialians, which encompasses extant birds.  Much of what we know about the diversity of this group in the Early Cretaceous comes from fossil specimens found in Liaoning, China.  However, many taxa are represented by specimens of unclear ontogenetic age.  With a better understanding of how dinosaurs may have changed in their appearance as they grew up, scientists can be more confident about their phylogeny, their evolutionary relationships and which character traits can be used to infer biology and the dinosaur’s position within the complex Jehol ecosystem.

This scientific paper identified several different types of feather associated with Wulong bohaiensis – pennaceous primary feathers, filamentous feathers and long tail feathers.  The team established that such plumage preceded skeletal maturity and full adult size in some dromaeosaurids.  Histological analysis of the Wulong holotype and a Sinornithosaurus specimen revealed that they developed mature feather coverings associated with adult animals after their first year, but before they had become fully grown.  This has implications for Paraves research as assumptions made about the adult age of a fossil specimen may not be accurate in the absence of histological analysis.

The scientific paper: “A new microraptorine theropod from the Jehol Biota and growth in early dromaeosaurids” by Ashley W. Poust, Chunling Gao, David J. Varricchio, Jianlin Wu, and Fengjiao Zhang published in The Anatomical Record.

17 01, 2020

Extra-terrestrial Impact Wiped Out the Dinosaurs

By | January 17th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Geology, Main Page|2 Comments

Mass Extinction Event Caused by Impact Event

One of the greatest controversies surrounding the Dinosauria is what actually caused the demise of the non-avian dinosaurs?  Around the end-Cretaceous mass extinction event, there was an enormous extra-terrestrial impact in the Gulf of Mexico.  A worldwide layer of clay, saturated in the rare Earth element iridium, marking the K-Pg geological boundary was first publicised by American father and son Luis and Walter Alvarez.  They postulated that an Earth impact event had resulted in this deposition and it was speculated that such a catastrophic event might have been responsible for the extinction of the dinosaurs.

New Study Suggests Dinosaur Extinction Due to the Extra-terrestrial Impact Event

Chicxulub impact event.

A reconstruction of the Chicxulub impact which marked the extinction of many terrestrial and marine forms of life, including the non-avian dinosaurs.

The “Smoking Gun” Evidence

Such an impact would have left an enormous crater, the search was on to find the “smoking gun” to support the theory regarding a meteorite, asteroid or perhaps a comet hitting the Earth.  Most researchers now agree, that the Yucatan peninsula in the Gulf of Mexico was ground zero.  However, there is a problem, as scientists are aware of a number of other potential candidates responsible for the extinction of a large amount of the planet’s biota some sixty-six million years ago.  For example, the Late Cretaceous was characterised by extensive volcanism.  Huge amounts of lava from the Deccan traps led to the formation of thousands of miles of  flood basalt.  The out-pouring of noxious gases as a result of this extensive volcanism could well have played a significant role in the extinction of many different kinds of organisms too.

Asteroid impact theory challenged: Blame the Deccan Traps.

In a new paper, a team of international researchers led by Dr Celli Hull from Yale University, conclude that the volcanism did not play a huge role in the extinction, but it may have played a significant role in shaping the rise of different species after the extinction event had occurred.

Impact Event the Most Likely Cause of End-Cretaceous Mass Extinction

The extinction of the dinosaurs.

An international team of scientists conclude that it was the extra-terrestrial bolide impact that caused the mass-extinction event.

Picture Credit: Everything Dinosaur

Analysis of Ancient Ocean Sediments

In order to disentangle the relative effects of the volcanism and the impact event, the scientists analysed deep sea sediment sections drilled from the North Atlantic, Pacific and South Atlantic Oceans.  They found that volcanic activity in the Late Cretaceous period caused only a gradual global warming of about two degrees Celsius, but this had no significant effect on marine ecosystems, and cooler conditions had returned prior to the extinction.

Hull et al investigated the timing of the Deccan outgassing by modelling in several scenarios, the effects of the gases ejected by volcanoes (sulphur and carbon dioxide).  Their results suggest that more than half of the total Deccan outgassing occurred well before the impact event, not just before it.  The scientists concluded that the timing of most of the atmospheric pollution from the extensive volcanism, just did not fit the extinction event.  The major volcanism is likely to have occurred at least 200,000 years before the extinction event.

One of the co-authors of the study, Professor Paul Bown (University College London), explained.

“Most scientists acknowledge that the last, and best-known, mass extinction event occurred after a large asteroid slammed into Earth 66 million years ago, but some researchers suggested volcanic activity might have played a big role too and we’ve shown that is not the case.”

The team’s models showed that the changes in the carbon cycle that resulted from the volcanism was mitigated by the oceans absorbing vast quantities of CO2.  This would have limited any global warming.

Fellow co-author Professor Paul Wilson (Southampton University), added:

“There’s been a big row about the cause of the mass extinction for decades.  The demise of the dinosaurs was the iconic event but they were large animals and there weren’t really that many of them so it’s tough to use them to figure out the cause.  We studied microscopic marine organisms called foraminifera and there are thousands of them in a teaspoon-full of ocean sediment.  To get them we drilled into the sea bed in waters nearly 5 kilometres deep not far from the watery grave of RMS Titanic off the coast of Newfoundland using a sort of geology time machine – a drill ship called the JOIDES Resolution run by one the world’s most successful international scientific collaborations, the International Ocean Discovery Program.”

The authors postulate that the volcanism may have played a role in shaping the evolution of Palaeogene species in the aftermath of the end-Cretaceous extinction event.

What About Hell Creek – Were Dinosaurs Already in Decline?

From a scientific perspective, it makes much more sense to examine the fossil record of planktonic foraminifera.  Relying on the non-avian dinosaurs as an indicator of palaeo-climate change some sixty-six million years ago is fraught with difficulties.  For instance, although many different types of life were affected by the end-Cretaceous extinction event, it is often only the dinosaurs that are mentioned by the media.  It is worth remembering that many other lifeforms died out.  There are not that many windows into the end of the Maastrichtian and the earliest part of the Palaeocene (Danian faunal stage).  One such example is the Hell Creek Formation, which provides a record of the last few million years of the Mesozoic.

Hell Creek – Prospecting for Fossils in the Upper Cretaceous Sediments

Looking for fossils - Hell Creek Formation.

Prospecting for fossils – Hell Creek Formation (Montana).

Picture Credit: University of California Museum of Palaeontology

Studies of the number and variety of dinosaur fossils excavated from the Hell Creek Formation and other slightly older geological formations, suggest that in the last ten million years of the Cretaceous, the number of dinosaur species fell by more than fifty percent.

An analysis of the youngest fifteen metres of sediments from the Hell Creek Formation, revealed just eleven different types of dinosaur.  In the uppermost strata, the last three metres of the Hell Creek Formation representing the end of the Cretaceous, only three types of dinosaur were recorded.  Whilst it can be difficult to accurately date and assess the chronology of strata, the study of dinosaur fossils from Hell Creek suggests that the Dinosauria may have been in decline (at least in this part of Laramida), prior to the impact event.  This decline, if it was a decline, could have been caused by the environmental effects of the extensive volcanism, or other factors for that matter.

We suspect that just like the Deccan Traps, this debate is going to rumble on for a considerable period of time.

15 01, 2020

Ediacaran Fossil Site Gains Protection

By | January 15th, 2020|Dinosaur and Prehistoric Animal News Stories, Geology, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

South Australian Fossil Site Purchase Supported by Billionaire

With so much bad news about the environment coming out of Australia due to the devastating bush fires, it is pleasing to report on a conservation success story.   A $1 billion (USD), nature fund has been used to buy a vast tract of outback South Australia containing some of the oldest animal fossils on Earth.  The acquisition safeguards an extremely important fossil site and helps support the Australian Government’s plans to gain World Heritage Site status for the area.

The Nilpena Fossil Fields (South Australia)

The Nilpena fossil fields (South Australia).

The Nilpena fossil fields preserve examples of Precambrian biota.

Picture Credit: Jason Irving

The 60,000-hectare (150,000 acre) Nilpena West property is 370 miles (600 kilometres), north of the South Australian capital Adelaide and was previously part of Nilpena Pastoral Station.  The property includes the Ediacara Fossil Site (Nilpena), which is listed on Australia’s National Heritage List and records a remarkable marine biota, documenting some of the earliest, large, multicellular creatures to have evolved on Earth.

Global not-for-profit organisation The Nature Conservancy, sourced funding from an anonymous donor in October 2019 to allow the purchase and protection to go ahead after the South Australian Government announced in March that it had reached an agreement with the land’s owners to purchase the site.  The purchased land is adjacent to the Ediacara Conservation Park and increases the size of the protected area ten-fold.

The Importance of the Flinders Range

Strange fossils, preserved in the sandstone of the Ediacaran hills of South Australia provided the first substantial evidence for the existence of complex life in the late Precambrian.  In 1946, Australian geologist Reginald Spriggs discovered fossilised impressions in this part of the Flinders Range, his unexpected discovery failed to enthuse the scientific community at first, his paper outlining the discovery was rejected by the academic journal “Nature”.  However, the significance of these exquisitely preserved fossils and what they represented – organisms associated with an ancient marine community, was soon realised.

An Example of Dickinsonia – One of the Fossilised Ediacaran Organisms Associated with the Nilpena Fossil Fields

Dickinsonia costata fossil.

The Ediacaran fossil Dickinsonia costata, specimen P40135 from the collections of the South Australia Museum.  The disc-like Dickinsonia is one of the creatures preserved at the Nilpena fossil site.

Picture Credit: Dr Alex Liu (Cambridge University)

To read an article about the bizarre Dickinsonia: Dickinsonia Definitely an Animal.

The sale has now been finalised with The Nature Conservancy announcing this week that funding from the Wyss Campaign for Nature, the once anonymous donor, had helped secure the acquisition.  The Wyss Campaign for Nature was founded two years ago, by the wealthy, Swiss-born philanthropist Hansjörg Wyss.  The purchased land will be permanently protected and managed by the South Australian Government.  It will be formally allocated to the Ediacara Conservation Park later this year.

A Map Showing the Location of the Nilpena Fossil Fields Relative to the Ediacara Conservation Park

A map of the Nilpena fossil fields site.

Nilpena fossil fields site.  The Nilpena Station purchase will greatly increase the protected area for the fossils.

Picture Credit: The Government of South Australia

The South Australian property is now permanently protected and managed for conservation by the South Australian Government. It will be added to the Ediacara Conservation Park later this year.

Scores of Species

Palaeontologists have excavated many hundreds of specimens representing three dozen different species, most of which are more than 550 million years old.  The fossils provide the first evidence of locomotion and sexual reproduction.  The space agency NASA, has examined the Ediacaran biota in a project to assess how life could evolve on other worlds.

The Nature Conservancy’s Australian Director of Conservation Dr James Fitzsimons explained that this purchase which would permit the formal protection of the 60,000 hectare property was a big win for conservation in South Australia.

He commented:

“The property contains significant biodiversity values including two threatened ecological communities and a number of threatened species.  Most critically, the property also covers extremely important sites that contain the oldest fossilised animals on Earth.”

South Australian Environment and Water Minister David Speirs said Nilpena West would soon be added to the South Australian public protected area estate and managed by the Department for Environment and Water.

The minister added:

“Its inclusion in the conservation estate will link the Ediacara Conservation Park to the Lake Torrens National Park and will support our nomination for the listing of areas of the Flinders Ranges as a World Heritage Site.”

When did life on land evolve?  An Ediacaran related article: When Did Life on Land First Evolve – Does the Ediacaran Biota Provide the Answer?

A recent article about how computerised tomography and other sophisticated research techniques are providing new insights into how the first animals evolved: Chinese Fossils Suggest Animal-like-embryos Evolved Before Animals.

Everything Dinosaur acknowledges the assistance of a press release from The Lead South Australia in the compilation of this article.

14 01, 2020

The First Stegosaur Dacentrurus armatus

By | January 14th, 2020|Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

The First Stegosaur Dacentrurus armatus

Situated amongst specimens of marine reptiles in the Mary Anning gallery at the London Natural History Museum is a remarkable fossil specimen.  Behind its glass case the viewer can make out a block of bones containing various vertebrae, a massive right femur (thigh bone), ribs and a near complete pelvis.  At approximately two metres across this is an impressive fossil specimen.  It is the holotype material for Dacentrurus armatus (NHMUK OR46013), the first large collection of dinosaur bones associated with a member of the Stegosauridae to be scientifically described and studied.

The Main Bone Block (D. armatus) at the Natural History Museum (London)

Dacentrurus armatus specimen on display at the Natural History Museum (London).

The Dacentrurus armatus specimen on display at the Natural History Museum (London).

Picture Credit: Everything Dinosaur

The fossils come from a clay quarry close to the town of Swindon in the county of Wiltshire.  Richard Owen (later Sir Richard Owen), who was to play a pivotal role in the foundation of the institute that we now know as the London Natural History Museum, studied the fossils and erected the name Omosaurus armatus in 1875.  The genus name, Omosaurus had already been used to describe a North American phytosaur (O. perplexus) in 1856.  Therefore, the original genus name for this armoured dinosaur was invalidated.  In 1902 the eminent American zoologist, Frederick Augustus Lucas erected Dacentrurus.

With the recently published paper describing a new specimen of Miragaia longicollum, a “Rosetta Stone” moment in vertebrate palaeontology permitting scientists to better understand the Dacentrurinae subfamily of the Stegosauridae, it is fitting that whilst in London an Everything Dinosaur team member took the opportunity to take a photograph of the main Dacentrurus block.  The beautiful fossils are notoriously difficult to photograph, but still, they continue to play a role in helping to decipher Late Jurassic stegosaurs.

One mystery still remains, why is this important dinosaur fossil on display in the marine reptiles gallery?  Perhaps, one day, these hugely significant fossils we will placed in the dinosaur gallery, where visitors could be given the opportunity to learn more about the world’s first extensively studied armoured dinosaur specimen.

To read our recent article on the M. longicollum paper: Turning a Stegosaur Fossil into the Rosetta Stone.

11 01, 2020

Thin-skinned, Grey Duck-billed Dinosaurs

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

Thin-skinned, Grey Duck-billed Dinosaurs

Scientists writing in the journal of The Palaeontological Association have published a remarkable study on the properties of the skin of duck-billed dinosaurs.  Analysis of fossilised hadrosaur skin, from the Yale Peabody Museum of Natural History (New Haven, Connecticut), suggests that the skin structure of these dinosaurs had more in common with living birds than with reptiles.  In addition, the skin is much thinner when compared to large, terrestrial mammals of comparable size such as elephants and rhinos.  In a blow to palaeoartists who like to adorn their ornithischian illustrations with a multitude of colours, the scientists conclude from an analysis of potential preserved skin pigments that hadrosaurids were grey in colour.

Hadrosaurs Could Have Been Largely Grey in Colour Just Like Big Terrestrial Mammals Alive Today Such as Elephants

Gryposaurus - Hadrosaur Model available from Everything Dinosaur.

The Wild Safari Prehistoric World Gryposaurus dinosaur model.  The model’s colouration being largely grey may actually reflect the true colouration of duck-billed dinosaurs.

Picture Credit: Everything Dinosaur

Getting Under the Skin of a Dinosaur

Scientists from Yale University, in collaboration with colleagues in Italy, investigated the chemical properties of a section of fossilised duck-billed dinosaur skin that had been preserved in three dimensions. The specimen (YPMPU 016969) was also subjected to detailed chemical mapping and microspectroscopy as well as scanning electron micrographs to establish the anatomical structure.

Two of the three layers associated with skin in tetrapods were identified, the outer layer (epidermis) and the dermis. The innermost layer, the subcutis, could not be identified in this study.  The dinosaur’s scales on the skin surface are very well-preserved.  They form an irregular, pebbly pattern with individual scales ranging in size from under one millimetre in diameter to much larger scales around 12 millimetres across.

Specimen Number YPMPU 016969 – The Fossilised Skin Studied

Fossilised duck-billed dinosaur skin.

The skin preserved in YPMPU 016969 (A), three‐dimensional skin and (B), the fossil counterpart. Scale bar represents 2 cm.

Picture Credit: Yale University

Three-dimensionally Preserved Pigment Bearing Bodies and  Blood Vessels

The detailed analysis of the fossilised skin and the samples taken permitted the scientists to identify three-dimensionally preserved eumelanin‐bearing bodies.  This enabled the researchers to propose that the dinosaur was mostly dark grey in colour, a skin colouration that reflects ecological parallels seen in today’s large, terrestrial animals such as elephants and rhinos.  However, caution is urged when it comes to determining the colouration of these types of dinosaurs.  There might be a preservation bias in favour of pigment cells that produce darker skin tones, other pigments may not have been preserved.  The section of fossil skin also permitted the researchers to trace blood vessels and dermal cells.

The Study Suggests That Large-bodied Hadrosaurids Were Similar in Colour to Today’s Large-bodied Terrestrial Mammals

Analysis suggests grey-coloured hadrosaurids.

A life reconstruction of a grey-coloured duck-billed dinosaur.

Picture Credit: Yale University

Surprisingly Thin Skin

The skin was found to be much thinner than that of living mammals of similar size.  The outer layer of skin is around 0.2 mm in thickness, whilst the dermis is estimated to have been up to 3 mm thick.  Although, no measurements for the subcutis layer could be made, in living elephants the skin is around 10-15 mm thick and in extant rhinos a skin thickness (all three layers, epidermis, dermis and subcutis), of 25 mm is not uncommon.

The relative thickness of the epidermis and dermis in YPMPU 016969 resembles that in birds more closely than that of reptiles.

If the skin of these large, Cretaceous herbivores is so much thinner than previously thought, then how does it fossilise more readily than the integumentary coverings of other dinosaurs?  After all, the most commonly preserved soft tissues associated with ornithischian dinosaurs are skin remains.  The researchers postulate that the unusual layering and the microstructure of hadrosaur skin may play an important role in its fossilisation potential.

The scientific paper: “Three-dimensional soft tissue preservation revealed in the skin of a non-avian dinosaur” by Matteo Fabbri, Jasmina Wiemann, Fabio Manucci and Derek E. G. Briggs published in Palaeontology – the journal of The Palaeontological Association

9 01, 2020

Animal-like Embryos Evolved Before Animals

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

Animal-like Embryos Evolved Before the First Animals Appear in the Fossil Record

Catching up with our reading, examining university press releases and having a little time to review some scientific literature enabled team members at Everything Dinosaur to get to grips with this research.  A new paper has been published in the journal “Current Biology” that sheds light on how the Animalia evolved.  Researchers led by scientists from the University of Bristol and Nanjing Institute of Geology and Palaeontology (Nanjing, China), have discovered that animal-like embryos evolved long before the first animals appear in the fossil record.

The study centred around a multicellular organism found in 609-million-year-old-rocks in Guizhou Province.  The organism is called Caveasphaera and it blurs the definition as to what is and what is not an animal.  However, analysis of tiny embryonic fossils suggests that as Caveasphaera developed it went from a single-cell stage to a multi-cellular stage and that it developed distinct, specialist cells and tissues.

Remarkable Fossils Reveal Ancient Organism May Have Set the Blueprint for Animal Body Plans

The embryology of 609 million-year old Caveasphaera.

Embryology of 609 million-year old Caveasphaera.

Picture Credit: Philip Donoghue and Zongjun Yin

Animals evolved from single-celled ancestors, subsequently, the Animalia diversified into thirty or forty body plans.  How and when animal ancestors made this evolutionary transition from a microbial state into complex multicellular creatures has been discussed and debated for many years.  The researchers, using sophisticated X-ray computer tomography, analysed tiny fossils from southern China and identified that a key step in this major step in the story of life on our planet occurred long before complex animals appear in the fossil record, in the fossilised embryos that resemble multicellular stages in the life cycle of single-celled relatives of animals.

X-ray Microscopy – Fossils on the Cellular Level

Analysis of the Ediacaran fossils preserved in the strata, revealed that the tiny 0.5 mm in diameter Caveasphaera material had been preserved all the way down to their component cells.

Co-author of the study paper, Kelly Vargas (Bristol University), commented:

“X-Ray tomographic microscopy works like a medical CT scanner, but allows us to see features that are less than a thousandth of a millimetre in size.  We were able to sort the fossils into growth stages, reconstructing the embryology of Caveasphaera.”

Fellow co-author Zongjun Yin, (Nanjing Institute of Geology and Palaeontology), added:

“Our results show that Caveasphaera sorted its cells during embryo development, in just the same way as living animals, including humans, but we have no evidence that these embryos developed into more complex organisms.”

Scanning Electron Microscope Image of Caveasphaera Showing Cell Division

Scanning electron microscope image of Caveasphaera.

A Caveasphaera embryo showing cellular structure and the growing tips where cells are dividing to increase their numbers.

Picture Credit: Philip Donoghue and Zongjun Yin

A Life Cycle that Mirrors the Development of Animals

The researchers concluded that Caveasphaera had a life cycle very close to the life cycle of animals which alternate between single-celled and multicellular stages, however, Caveasphaera goes one step further, reorganising those cells during embryology.  This is the earliest fossil evidence found to date that shows such development and the setting up of more complex distinct tissue layers and organs.

Whether the enigmatic, Caveasphaera is a member of the Animalia remains open to debate.  It resembles the embryos of some starfish and corals but no adult forms are known as they may not have been easily fossilised.

Professor Philip Donoghue from the University of Bristol’s School of Earth Sciences, stated:

“Caveasphaera shows features that look both like microbial relatives of animals and early embryo stages of primitive animals.  We’re still searching for more fossils that may help us to decide. Either way,  fossils of Caveasphaera tell us that animal-like embryonic development evolved long before the oldest definitive animals appear in the fossil record.”

Sequential Development of Caveasphaera Mirrors the Development Seen in the Animalia

Computer generated images show embryology of Caveasphaera.

Embryology of 609 million-year old Caveasphaera.  Computer models based on X-ray tomographic microscopy of the fossils, showing the successive stages of development.

Picture Credit: Philip Donoghue and Zongjun Yin

The scientific paper: “The early Ediacaran Caveasphaera foreshadows the evolutionary origin of animal-like embryology” by Z. Yin, K. Vargas, J. Cunningham, S. Bengtson, M. Zhu, F. Marone and P. Donoghue published in Current Biology.

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

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