Wild Safari Prehistoric World Pachycephalosaurus “Battle Damage”
Sometimes a model manufacturer goes that little bit further when it comes to adding a degree of authenticity to its figures. A case in point is Safari Ltd and their recently introduced Wild Safari Prehistoric World, Pachycephalosaurus. This beautifully painted replica depicts an injury to the skull of this “bone-headed” dinosaur. There is a small, brown-coloured mark on top of the skull. Eagle-eyed Everything Dinosaur team members noticed this feature when looking at pre-production images, but it had been difficult to spot in some promotional shots.
However, we can confirm this little bit of pachycephalosaur pathology is indeed an integral part of the model.
Showing the “Pachycephalosaur Pathology” – The Wild Safari Prehistoric World Pachycephalosaurus with the Mark on its Head
A close-up view of the top of the head of the Wild Safari Prehistoric World Pachycephalosaurus model with the “battle damage” highlighted. Picture credit: Everything Dinosaur.
A number of theories have been put forward as to why pachycephalosaurs tended to have highly ornate, often very thick skulls. These anatomical features probably did not evolve to protect their brains, the brains of these types of dinosaur are proportionately no bigger than many other types of ornithischians. They probably did not have a defensive role, after all, to a large tyrannosaurid a thick, reinforced skull would have been not much of an obstacle to overcome if it were fortunate to catch a pachycephalosaur.
Many palaeontologists believe these characteristics evolved as these animals competed with each other in combat over hierarchical status in the herd, or the right to mate. This theory was, we believe, first postulated by the distinguished American vertebrate palaeontologist Edwin Colbert in 1954. Since then, a number of studies have been undertaken to verify/refute this idea: Study Sheds New Light on the Intraspecific Combat of Pachycephalosaurs.
Pachycephalosaurus wyomingensis Replica Skull
Pachycephalosaurus wyomingensis replica skull. In some specimens the skull bone is more than twenty centimetres thick.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
However these Late Cretaceous dinosaurs used their heavily ornate and robust headgear remains open to speculation, but one thing is for sure, the Wild Safari Prehistoric World Pachycephalosaurus model certainly shows lots of detail.
A Beautiful and Very Detailed Dinosaur Model
The new for 2020 Wild Safari Prehistoric World Pachycephalosaurus model. The “battle damage” to the skull can be seen in this image of the dinosaur.Picture credit: Everything Dinosaur.
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 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.
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 with approximate position of Thanatotheristes (red) and Daspletosaurus spp. fossil finds (blue).
Picture credit: Everything Dinosaur from D. Eberth (Dinosaur Provincial Park)
The Stratigraphy of the Belly River Group
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 Beasts of the Mesozoic range of articulated figures has recently introduced a tyrannosaur series.
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.
Evidence Found of Late Triassic Phytosaurs in Southern Africa
A team of international researchers have reported the discovery of phytosaur fossils from southern Africa. A local safari guide noticed some fossils eroding out of sediments on the shores of Lake Kariba in northern Zimbabwe. Field expeditions to the area were undertaken in 2017 and 2018 and the researchers, which included scientists from the London Natural History Museum, were able to map the fauna and flora of a Late Triassic freshwater ecosystem.
Fragmentary remains including dermal scutes (armour), teeth and bones were found and this is the first evidence that crocodile-like phytosaurs were present in southern Africa. Many palaeontologists thought that these aquatic reptiles were confined mostly to the tropics and sub-tropics. These fossils suggest that phytosaurs may have been more widely distributed than previously thought.
A Museum Exhibit Featuring a Typical Phytosaur (National Museum of Wales)
A museum exhibit featuring a typical phytosaur.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Not Closely Related to Modern Crocodiles
Phytosaurs superficially resemble modern crocodiles, especially long, thin snouted forms like the American crocodile and the Gharial, although they are not closely related. It is likely that phytosaurs filled the same ecological niche as extant crocodilians, hunting for fish and small reptiles/amphibians around bodies of freshwater, although it is now known that some phytosaurs adapted to a marine environment: Marine Phytosaurs of the Triassic.
The Phytosauria clade and its superficial similarity to crocodilians is an example of convergent evolution, whereby, similar features and traits evolve in unrelated species. One of the easiest ways to tell a crocodile from a phytosaur is to look at the skull. The jaws and teeth may look similar but with crocodiles the pair of nostrils are located towards the front of the snout whilst in phytosaurs the nostrils are located towards the back of the snout, much closer to the eyes.
The Location of the Nostrils in Phytosaurs
The location of the nostrils in a phytosaur. The nostrils are located towards the rear of the snout, close to the eyes not at the anterior portion of the snout as in the Crocodylia. Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Mapping the Fossilised Remains of Phytosaurs
Fossilised remains of phytosaurs have been found in Europe, North America, Morocco, Madagascar, India and Brazil. The strata in which these fossils are found would have been at a low latitude when the sediments were laid down. In comparison, the Lake Kariba fossil finds indicate that large phytosaurs were living very far from the equator. Until now, phytosaurs had been unknown from high southerly latitudes.
Professor Paul Barret, (London Natural History Museum), a co-author of the scientific paper stated:
“This is the first discovery of phytosaurs from southern Africa. It provides us with our first snapshot of a mostly aquatic environment from this part of the world, which was part of the ecological puzzle that was missing before.”
The study has also permitted the researchers to properly date the rocks in which the fossils were found, placing the entire site into much greater context with the other Triassic-age formations found across South Africa, Zambia, Tanzania, Namibia and Botswana.
Phytosaurs are Environmental Indicators
The presence of large phytosaurs in Zimbabwe, is a good indicator of the environment and climatic conditions in the area some 210 million years ago.
Professor Barrett explained:
“Phytosaurs usually need permanent bodies of water. They’re big animals that liked large lakes and rivers.”
These kinds of environments would not have been unusual during the Late Triassic, which is one of the reasons why the distinct lack of any phytosaurs from southern Africa is particularly curious.
Everything Dinosaur acknowledges the assistance of a news release from the London Natural History Museum in the compilation of this article.
Everything Dinosaur has been awarded the Feefo Platinum Trusted Service award, a newly created accolade that provides independent verification of a company’s customer service credentials. Every year since Everything Dinosaur signed up to Feefo, the UK-based dinosaur company has won the Feefo Gold Trusted Service award and in recognition of the company’s continually high service standards, a new standard was introduced by Feefo for 2020 – platinum.
Everything Dinosaur Has Won Feefo’s Highest Award for Customer Service
Everything Dinosaur has won the Feefo Platinum Service Award for 2020.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
The Platinum Trusted Service Award a Prestigious Seal of Approval
The award is based on genuine feedback and ratings from Everything Dinosaur customers. At present, Everything Dinosaur has over 450 published customer reviews and has a 5-star rating for customer service. The Feefo Platinum Trusted Service award provides an independent seal of approval and demonstrates that an organisation is delivering exceptional customer service as rated by the customers themselves.
Feefo have given Platinum Trusted Service awards to businesses who have achieved the “Gold” standard for three consecutive years. The Feefo Gold Trusted Service award recognises those who have collected at least 50 Feefo reviews in a year and have achieved a service rating of at least 4.5 out of 5-stars.
Everything Dinosaur’s Certificate of Achievement – 2020 Platinum Trusted Service Award Winners!”
Everything Dinosaur has been awarded the Platinum Trusted Service award from Feefo.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Everything Dinosaur Comments
Commenting on the award a spokesperson from Everything Dinosaur stated:
“We are very proud and delighted to have received this new award from Feefo as this accolade genuinely reflects the views of our customers, who are the most important judges of all. Team members all work hard to ensure that everyone who purchases from Everything Dinosaur is looked after properly. We are continually striving to improve and we are looking forward to helping dinosaur model fans and collectors in what is going to be another very busy year for us.
Congratulating Everything Dinosaur on winning this very special award, the Director of Customer Success at Feefo, Steph Heasman added:
“The Trusted Service award has always been about recognising companies that go way beyond the norm in customer experience and generate great feedback from happy customers. This year we’ve been delighted to see so many companies using Feefo to provide outstandingly high levels of all-round service.”
A quick trip to the London Natural History Museum to gain some inspiration for a project that Everything Dinosaur team members have been invited to participate in. Once there and with our mission accomplished, there was just time to take a look at some of the superb fossil exhibits on display adjacent to the Earth Hall and the British Geological Survey display. It was like meeting old friends again with a chance to admire the Megatherium specimen and the amazing marine reptiles within the “Green Zone”. One of our favourite specimens, is this cross-section of a substantial ammonite.
With all those chambers exposed , the fossilised remains of this large marine invertebrate remind us of a piece of modern art.
A Beautiful Ammonite Fossil on Display
A stunning fossil of a Jurassic ammonite on display at the London Natural History Museum.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
The Ammonite Asteroceras stellare?
We suspect that this is an example of Asteroceras stellare, an ammonite species associated with the Lower Jurassic of Europe from around 195 to 188 million years ago. Some specimens of A. stellare have shells nearly a metre in diameter. Gigantism in cephalopods has arisen on numerous occasions during the long evolutionary history of this Class of the Mollusca. Today, we have the giant squid (Architeuthis), whilst in the Ordovician, one of the world’s first super-predators was a cephalopod, the enigmatic Cameroceros.
An Ammonite Model – Pleuroceras
CollectA Age of Dinosaurs Popular Size Pleuroceras ammonite model.
The image (above) shows the CollectA Popular Pleuroceras ammonite model.
As for why some types of ammonite grew so large, whilst most could comfortably fit in the palm of your hand, remains a mystery. Scientists are uncertain as to what environmental factors are the driving forces in the evolution of giant forms in some types of animal, however, such large animals could be linked to a bountiful supply of oxygen in the atmosphere and subsequently dissolved in sea water.
The specimen on display at the Natural History Museum, may not be the biggest ammonite fossil, but to us we think it is one of the most beautiful exhibits to be seen in the whole of the Earth Hall.
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 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.”
In December, Everything Dinosaur received stocks of the 1:35 scale Rebor Stegosaurus armatus dinosaur model. This beautiful figure is available in three colour schemes, “plain”, “woodland” and many team member’s personal favourite – “mountain”.
We had been asked to demonstrate how the tailpiece fitted into the model and we did produce a short video demonstrating how to insert the tail into the slot at the back of the figure, but we had more footage so we have posted up a slightly longer video that provides a little more detail about this excellent armoured dinosaur replica.
Providing More Information About the Rebor Stegosaurus armatus Figure
In this short video, (it is a little under one minute forty-five seconds in length), we show the “mountain” colour scheme figure as well as images of the two other colour variants “plain” and “woodland”. We comment on the tailpiece and demonstrate how to connect it to the body. In addition, we briefly discuss the fossil material that was once the type specimen for the Stegosaurus genus.
This fossil material was very incomplete, only the rear portion of the animal was preserved and only one iconic plate was found in association. The fossils once ascribed to S. armatus, were replaced as the designated type material for the genus by much more complete Stegosaurus stenops material in a ruling by the International Commission on Zoological Nomenclature (ICZN), in 2013.
We take this opportunity to thank Rebor for producing such an excellent dinosaur model.
The Taxonomy of the Stegosauridae
Stegosaurus might be an iconic dinosaur, but compared to the horned dinosaurs of the Late Cretaceous such as Triceratops and its close relatives, there remains a lot of debate as to the exact taxonomic make-up of the Stegosauridae.
The Rebor S. armatus Dinosaur Model is Available in Three Colour Variants
The Rebor 1:35 scale Stegosaurus (S. armatus) is available in three colour variants “plain”, “mountain” and woodland”. Which one is your favourite?Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
To view the Rebor Stegosaurus figures and the rest of the Rebor models and figures available from Everything Dinosaur: Rebor Replicas, Models and Figures.
Committed to Making More Videos Including Product Reviews
At Everything Dinosaur, we are committed to making and posting up more videos onto our YouTube channel. We hope to put up a new video onto our YouTube channel every week, so long as other work commitments permit.
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.
The beautifully preserved and almost complete W. bohaiensis fossil specimen.
Picture credit: Ashley W. Poust (University of California)
Wulong bohaiensis – 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.”
Studying the Histology of the Fossil Bones
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
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
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.
Our thanks to dinosaur and fossil fan Caroline who on receipt of her delivery from Everything Dinosaur was inspired to send us a little thank you card illustrated with a sauropod sketch. What a beautiful illustration of a dinosaur! The drawing is entitled “Young Diplodocus Going for a Dip”.
A “Young Diplodocus Going for a Dip”
A young Diplodocus going for a dip.
Picture credit: Caroline Smalley.
Inside the card, Caroline had written:
“Thank you for your kindness, fantastic customer service and speedy delivery.”
You are most welcome, happy to help out where we can and thank you again for your card with the wonderful dinosaur illustration.
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
An extra-terrestrial impact event.
Picture credit: NASA
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.
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 K-Pg extinction event was exacerbated by the high levels of sulphur at the extraterrestrial impact site that led to prolonged global cooling. Picture credit: James McKay.
Picture credit: James McKay
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.”
Professor Wilson added:
“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.
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.
Difficulties in Dating Strata
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.
