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11 02, 2018

Magma Outflow from Mid-Ocean Ridges Contributed to Dinosaur Demise

By | February 11th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Geology, Main Page|0 Comments

Magma Outpourings Along Oceanic Boundaries of Tectonic Plates

Scientists have concluded that magma outpourings along the edges of tectonic plates in the deep ocean may have contributed to the mass extinction event that marked the end of the Mesozoic, some sixty-six million years ago.

Researchers from the University of Oregon, in collaboration with colleagues from the University of Minnesota, identified gravity-related fluctuations dating to around the time of the end Cretaceous along ocean ridges that point to the worldwide release of volcanic magma.   The outpouring of molten rock could have contributed to the global climatic catastrophe that marked the extinction of about 70% of all terrestrial lifeforms including the dinosaurs and their flying reptile cousins (Pterosauria).

The Extra-terrestrial Impact Event Could Have Exacerbated Volcanism Including Along Oceanic Ridges

Magma flows along ocean ridges.

Increased outpourings of magma along ancient ocean ridges could have contributed to the end Cretaceous extinction event.

Picture Credit: University of Oregon/E. Paul Oberlander, Woods Hole Oceanographic Institution, Graphic Services

Lead author of the scientific paper, published in the academic journal “Science Advances” Joseph Byrnes, (Department of Earth Sciences, University of Minnesota), stated:

“We found evidence for a previously unknown period of globally heighted volcanic activity during the mass-extinction event.”

A “One-Two” Knockout Blow

The team’s analysis of the strength of gravity along these ancient ocean ridges, points to a pulse of accelerated global volcanism that along with the massive outpourings known as the Deccan Traps of India would have significantly impacted upon the planet’s climate.  How much the enormous Deccan Traps contributed to the demise of the Dinosauria has been debated for decades.  Huge volcanic events, fortunately quite rare, such as the outpourings of molten rock that at some places in India, are more than two kilometres thick and cover much of the western portion of the sub-continent, can have a colossal effect on the Earth’s climate.  When these events do occur, they are very often linked to global mass extinctions.  The expulsion of gas and ash into the air can block out the sun causing plants to die and ecosystems to collapse.  Acid rain is also associated with the release of sulphur dioxide into the atmosphere from volcanoes.

With the discovery of the Chicxulub impact crater on the Yucatan Peninsula (Mexico), scientists have debated how much of an effect the Deccan Traps eruptions did have.  Seismic data suggests that part of India was already active when the extra-terrestrial body hit the Earth around 66 million years ago, however, the impact was so massive, the resulting seismic shock waves moved through the Earth’s crust and probably led to an acceleration of those eruptions.

Co-author, Leif Karlstrom added:

“Our work suggests a connection between these exceedingly rare and catastrophic events, distributed over the entire planet.  The meteorite’s impact may have influenced volcanic eruptions that were already going on, making for a one-two punch.”

The idea that the impact event increased volcanism gained credence in 2015 following research from scientists based that the University of California, Berkeley.  They proposed that powerful seismic waves could have exacerbated distant volcanic eruptions, making the Deccan Traps even more active.

Mapping Gravity Anomalies in Mid-Ocean Late Cretaceous Environments

Mapping gravity anomolies.

Coloured and black lines mark mid-ocean ridges 66 million years ago and reflect seafloor spreading rates and gravity anomalies after the impact event.

Picture Credit: Joseph Byrnes

This new research extends this exacerbated eruption idea to oceanic basins worldwide.  To conduct the research, a geological map of the seafloor was divided into equally sized sections and the history of the ocean basins plotted back in time for more than 100 million years.  At around 66 million years ago, the approximate time of the Chicxulub impact event, evidence for a “short-lived pulse of marine magmatism”, along the ancient ocean ridges where tectonic plates meet was found.  This pulse is indicated by a spike in the rate of the occurrence of free-air gravity anomalies found in the data.  Free-air gravity anomalies, measured in tiny increments (milligals), account for variations in gravitational acceleration, found from satellite measurements of additional seawater collecting where the Earth’s gravity is stronger.  Byrnes found changes in free-air gravity anomalies of between five and twenty milligals associated with seafloor created in the first million years after the impact event.

The scientific paper: “Anomalous K-Pg–aged Seafloor Attributed to Impact-induced Mid-Ocean Ridge Magmatism” by Joseph S. Byrnes and Leif Karlstrom published in the journal “Science Advances”

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10 02, 2018

Polar Hypsilophodonts in the Spotlight

By | February 10th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

New Study Looks at the Growth Rates of Polar Hypsilophodonts

Researchers from Museums Victoria (Melbourne, Australia) and the Oklahoma State University Centre for Health Studies, have published a new paper in the academic journal “Scientific Reports” that examines the growth rates of polar dinosaurs, specifically the growth rates of those fleet-footed Ornithischians the hypsilophodontids.  Palaeontologists have long-debated whether these small dinosaurs, which were geographically widespread during the Early Cretaceous, showed different growth rates between high latitude forms and those that lived closer to the Equator.

An Illustration of a Typical Hypsilophodont Dinosaur

Hypsilophodont.

A typical hypsilophodontid dinosaur.

Picture Credit: Everything Dinosaur

The Perils of Being a “Polar” Dinosaur

Dinosaurs that lived in high latitude habitats such as those that lived on the southernmost portions of Gondwana, had to endure low temperatures, plus periods of prolonged darkness as the sun dropped below the horizon.  Although, nowhere near is as cold as the Antarctic today, close to the South Pole in the Early Cretaceous was quite a foreboding, formidable environment.  However, several types of non-avian dinosaurs, including several hypsilophodonts seem to have flourished.  Four taxa have been described to date, from two principle locations namely:

  • Fulgurotherium australe from the Flat Rocks and Dinosaur Cove locations (Victoria)
  • Qantassaurus intrepidus (Flat Rocks location)
  • Leaellynasaura amicagraphica from Dinosaur Cove
  • Atlascopcosaurus loadsi (Dinosaur Cove)

As all these genera are named from fragmentary remains (elements from the jaw and individual teeth), with the exception of L. amicagraphica, which is known from more substantial material, in the absence of more fossil remains some of these taxa are regarded as nomen dubia.

The microstructure of limb bones (femora and tibias) were analysed to identify growth trends, the study revealed that there were probably two genera present in those fossils studied which had come from Dinosaur Cove.  Bone microstructure alone, could not distinguish taxa within the sample of bones from the Flat Rocks area.  The researchers, which included Dr Thomas Rich and his partner Dr Patricia Vickers-Rich conclude that further histological study of hypsilophodont material from these sites may help to confirm the number of genera present as well as to help improve the data on polar dinosaur growth rates.  Leaellynasaura was named in honour of the couple’s daughter Leaellyn Rich.

Several Species Likely

Flat Rocks and the Dinosaur Cove locations are separated by Port Phillip Bay, they are approximately 120 miles (200 kilometres) apart.  These areas are also distant from a geological perspective, with the Flat Rocks locality being made up of sedimentary rocks that date from around 133 – 128 million years ago (Late Valanginian or Barremian faunal stages of the Early Cretaceous).  Whereas, the rocks that formed Dinosaur Cove on the other side of Cape Otway, are much younger, being laid down approximately 106 million years ago (Albian faunal stage of the Early Cretaceous).  Based on the temporal range that these fossils represent, then it is quite likely that these dinosaur fossils from the coast of Victoria do, indeed, represent several genera.

Growth Rates Amongst Polar Hypsilophodonts

The research into the bone microstructure of the limb bones of these types of polar dinosaur reveals that both the Flat Rocks and Dinosaur Cove specimens were growing in a similar way, at a similar rate to many typical small-bodied vertebrates.  These animals tended to have lower annual growth rates when compared to larger vertebrates.  The palaeontologists note that the large (eight metres long), Ornithischian Maiasaura from the Late Cretaceous of the United States took around eight years to reach adult size, whereas one of the specimens in the study seems to have reached maturity a year earlier, but it was a much smaller-bodied dinosaur, only growing at a fraction of the rate of the larger Maiasaura.

Transverse Sections from the Femur of a Hypsilophodont Used in the Study

Bone microstructure and histology in hypsilophodont limb bones.

Images of a cross-section of a hypsilophodont right femur showing histology and bone microstructure.

Picture Credit: Scientific Reports

The researchers did note that although the polar hypsilophodontids grew quite slowly compared to their larger relatives, the bone histology studies revealed that they had a relatively elevated growth rate for the first few years of their life.  Growing up relatively quickly, or at least reaching a certain threshold body size could have been an evolutionary response to avoid predation.

The paper published in “Scientific Reports”, is the first study of its kind into the growth rates of Australian polar hypsilophodonts.  The team conclude that these dinosaurs might have reached maturity in about five to seven years.  As adults, these genera only rarely exceeded lengths of 2.8 metres, most of which was tail and individual body mass for most of these dinosaurs was under fifty kilograms.

The research could be extended to include an analysis of hypsilophodontid limb bones excavated from lower latitudes.  A more complete comparison between the ontogeny of hypsilophodonts from different parts of the world could then be made.

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9 02, 2018

Out of Africa – Much Earlier Than Expected

By | February 9th, 2018|Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

Human Jawbone Fossil Rewrites our History

The discovery of a fossilised upper jawbone, complete with teeth, has rewritten the history of our own species and supports the theory as proposed by genetic studies that H. sapiens migrated out of Africa much earlier than previously thought.  Most palaeoanthropologists contend that our species Homo sapiens originated in Africa and then at some point in the distant past migrated out of Africa spreading into the Middle East, Asia and Europe before colonising the rest of the world.  Human fossils found outside Africa have been dated to 120,000 to 90,000 years ago (Tarantian faunal stage of the Late Pleistocene), the discovery of a human jawbone fossil at Misliya Cave on the western slopes of Mount Carmel, Israel, demonstrates that modern humans were already present in northern Israel at least 55,000 years earlier.

The Fossil Jawbone that Reinforces the Idea that Modern Humans Migrated Out of Africa Much Earlier

Modern human jawbone fossil.

The left maxilla from a modern human found in northern Israel.

Picture Credit:  Israel Hershkovitz Tel Aviv University

Levallois Technology

The international team of scientists, including  Israel Hershkovitz (Tel Aviv University) and Rolf Quam from the Department of Anthropology at Binghamton University, examined the sediments in the cave associated with the human jawbone fossil find.  There has been a research project associated with the Misliya Cave site for several years.  This new research builds upon previous studies and it supports the idea that the people at this location were making and using a range of sophisticated stone tools reminiscent of the tools associated with the earliest modern humans in Africa (Levallois technology).  The sediments reveal a series of well-defined hearths as well as numerous animal remains and stone tools.  An analysis of the human remains, dating the sediments and the fossil itself, suggests an approximate age range of between 177,000 and 194,000 years old, making this jawbone the oldest member of the Homo sapiens species to have been found outside of Africa.

The research team conclude, that the fossil, known as the “Misliya maxilla” along with the abundant stone tools, indicates that the emergence of this technology is linked to the appearance of our species in this region of the Middle East.

For an article that summarises research from 2016 that questions the relatively late migration of modern humans out of Africa: Out of Africa Earlier than Thought?

Another 2016 article that looks at the evidence in support of a theory that suggests modern humans evolved independently in Asia: Did Humans Evolve Independently in Asia?

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8 02, 2018

Dinosaurs Reveal the Geographical Signature of an Evolutionary Radiation (Part 2)

By | February 8th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

Dinosaurs Reveal the Geographical Signature of an Evolutionary Radiation

Yesterday, Everything Dinosaur posted an article on the newly published scientific paper that examined how the Dinosauria radiated out from their suspected South American origins and came to dominate terrestrial ecosystems around the world.  The research was conducted by scientists based at Reading University and their paper was published this week in the academic journal “Nature Ecology & Evolution”.

To read our article on this research: The Evolutionary Radiation of the Dinosauria Mapped

Building upon earlier research, the Reading University scientists believe that the dinosaurs were already in decline before the final coup de grâce that marked the end of the Cretaceous and the demise of the non-avian dinosaurs.  The dinosaurs spread across the planet, but they began to run out of space to migrate into, becoming victims of their own success.

Everything Dinosaur has received special permission from the University to publish some of the images created by the researchers that plot the routes taken by various dinosaur species as they spread across the world.  The pictures (below), show six reconstructed paths from the dinosaurian root node (black circle) to the fossilised species (black square).  The coloured circles represent the centroids of the reconstructed ancestral locations (these are used for visualisation purposes only and posterior distributions of estimated ancestral locations are used in all analyses).  These maps help to demonstrate the conclusions drawn by the researchers.  Take for example, the first image, that of the path of Rhoetosaurus (R. brownei).  R. brownei was a Sauropod, its fossils are found in eastern Australia and it lived some 170 million years ago.

The Evolutionary Path of Rhoetosaurus brownei

Picture Credit: University of Reading (silhouette credit: Remes K, Ortega F, Fierro I, Joger U, Kosma R et al, silhouette represents Spinophorosaurus nigerensis)

The Evolutionary Path of Archaeopteryx lithographica is Plotted

Plotting the evolutionary path of Archaeopteryx lithographica.

The evolutionary path of Archaeopteryx lithographica.

Picture Credit: University of Reading (silhouette credit: Scott Hartman)

Archaeopteryx lithographica lived around 150 million years ago, its fossils have been found in the limestone quarries of southern Germany.  All the evolutionary paths that have been created by the researchers have been plotted onto geological age level palaeomaps from the time at which the fossil species is dated to (grey).  All preceding age level palaeomaps are plotted in white.

Plotting the Path of the Ornithischian Dinosaur Stegosaurus stenops

Plotting the evolutionary path of the armoured dinosaur Stegosaurus stenops.

Plotting the evolutionary path of Stegosaurus stenops.

Picture Credit: University of Reading (silhouette credit: Scott Hartman)

Like Archaeopteryx, Stegosaurus stenops fossils are associated with Upper Jurassic strata.  However, this research suggests that unlike the Archaeopteryx lineage, which migrated into eastern Laurasia, the evolutionary path of S. stenops was oriented towards western Laurasia, fossils of this iconic armoured Ornithischian being associated with the Morrison Formation of the western United States.

The Evolutionary Path of Andesaurus delgadoi is Plotted

The evolutionary path of Andesaurus delgadoi is plotted.

Plotting the path of the Titanosaur Andesaurus delgadoi.

Picture Credit: University of Reading (silhouette credit: T. Tischler, the silhouette represents the related titanosaurid Wintonotitan wattsi)

Late Cretaceous Migrations

The titanosaurid A. delgadoi lived some 97 million years ago (Cenomanian faunal stage of the Late Cretaceous).  Note how the world map has changed in the illustrations, reflecting the change in the position of the continents.  The known fossil evidence suggests that the majority of the titanosaurids were restricted to Gondwana for most of the Cretaceous species.  Only in the very Late Cretaceous did a land bridge form, permitting these dinosaurs to migrate into North America.

Path of Dromaeosaurus albertensis 

Plotting the path of Dromaeosaurus albertensis .

The path of D. albertensis, dromaeosaurs migrated into North America from high latitudes.

Picture Credit: University of Reading (silhouette represents Dromaeosauroides bornholmensis known from Upper Cretaceous rocks from Denmark)

The researchers conclude that the dromaeosaurids associated with North America crossed over from northern Asia.

Last but not least, no evolutionary study mapping the spread of the dinosaurs would be complete without reference being made to the Tyrannosauroidea.  The map below, shows the path plotted for Tyrannosaurus rex.

Plotting the Path for T. rex

Plotting the evolutionary path of Tyrannosaurus rex.

T. rex evolutionary path is plotted.

Picture Credit: University of Reading

From their South America origins, this most famous of the Theropoda seems to have traversed Laurasia before heading westwards to become the dominant, apex predators in the Late Cretaceous (Laramidia and (most likely) Appalachia).

The authors of the scientific paper state that all silhouettes were downloaded from www.phylopicdotorg.

The scientific paper: “Dinosaurs Reveal the Geographical Signature of an Evolutionary Radiation” by Ciara O’Donovan, Andrew Meade and Chris Venditti published in Nature Ecology & Evolution.

Everything Dinosaur acknowledges the help of Reading University in the compilation of this article.

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7 02, 2018

Evolutionary Radiation of the Dinosauria Mapped

By | February 7th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

Dinosaurs Reveal the Geographical Signature of an Evolutionary Radiation

The fact that the dinosaurs came to dominate terrestrial ecosystems during the Mesozoic is not controversial.  There is plenty of fossil evidence to suggest that dinosaurs evolved into a myriad of different species (some 1,300 genera have been described to date), these fossils are geographically widespread.  Thanks, in part, to their origins on the supercontinent Pangaea and to the vagaries of continental drift, dinosaurs lived all over the world, from the Antarctic to the Arctic circle.

However, not that much is known about how the dinosaurs spread and became globally distributed.  Indeed, just how quickly the Dinosauria radiated and how soon they rose to prominence in terrestrial ecosystems remains very much open to debate.  Researchers from the University of Reading have attempted to map the geographical spread of the “terrible lizards” and they conclude that the migration of dinosaurs around the world was so rapid, that eventually they ran out of land to colonise and this might have contributed to their extinction.

Dinosaurs Spread from South America to the Rest of the World

Dinosaur diversification and migration coincided with the break-up of Pangaea.

The spread of the Dinosauria – if they originated in South America.  The approximate location of the famous Triassic fossil site (Ghost Ranch) is indicated by the yellow arrow.

Picture Credit: Everything Dinosaur

The Evolution of the Dinosaurs – It’s a Bit of a Puzzle

Just when and where the dinosaurs rose to dominate the land is hotly debated.  The fossil record for early dinosaurs is very poor and extremely fragmentary.  This problem is compounded by the blurring of the definition of the Dinosauria, as living alongside the true dinosaurs for tens of millions of years were their closely related counterparts which together with the dinosaurs comprise the clade Dinosauromorpha.  Palaeontologists can find it extremely difficult to distinguish between a true Triassic dinosaur and a contemporary dinosauromorph.  It seems that in the Triassic, the ancestral forms of the Dinosauria, lived alongside the true dinosaurs for millions of years.

This problem is compounded by the fact that the dinosaur/pterosaur/bird branch of the Archosauria (Avemetatarsalia), were in the evolutionary shadow of the crocodile branch of the “ruling reptiles” the Crurotarsi, for much of the Middle and Late Triassic.  If you were able to interview a Coelophysis or a Tawa (both dinosaurs from the famous Ghost Ranch location of New Mexico), they would have described an ecosystem dominated by other types of Archosaur, not dinosaurs.  With the exception of the abundance of Coelophysis specimens, there are relatively few dinosaur fossils from the Ghost Ranch location, dinosaurs may have only made up around 20% of the terrestrial fauna.

Coelophysis – A Typical Example of a Triassic Theropod

Coelophysis flock.

A flock of Coelophysis descend on a waterhole (Ghost Ranch).

Picture Credit: Matt Celeskey

Jumping into the Jurassic

After the End Triassic mass extinction event, it seems to have been a different story.  The dinosaurs seem to have rapidly risen to dominance and soon the landscape was being dominated by giant herbivores such as the long-necked Cetiosaurs and the first super-sized carnivores such as Dilophosaurus, Cryolophosaurus and the first of the Megalosaurs.  The Reading University team modelled the spread of the dinosaurs by reconstructing the dinosaurs’ ancestral locations (using South America as the starting point for the dinosaur radiation), they then examined the spatial mechanisms that underpinned the spread of the Dinosauria.  The research shows that the speed of this expansion meant that the dinosaurs quickly became cosmopolitan and subsequently ran out of land.  This lack of space then seriously impeded their ability to produce new species.

Typical Early Jurassic Dinosaurs Show an Increase in Size Compared to Late Triassic Counterparts

Early Jurassic giants.

Examples of some of the larger dinosaurs from the Early Jurassic.

Picture Credit: Everything Dinosaur

Building Upon Previous Research

This new study, published in “Nature Ecology and Evolution”, builds upon previous research from Reading University, published in 2016, that concluded that the dinosaurs were in decline around 50 million years before the mass extinction event that saw the demise of the non-avian forms.

To read Everything Dinosaur’s article about the 2016 study: The Fifty Million Year Decline of the Dinosaurs

Lead author of this new research, evolutionary biologist at the University of Reading, Ciara O’Donovan explained:

“Fossil evidence has shown us where the dinosaurs started out and where they died, but there is an important middle period that little was known about.  Our research fills this gap in prehistory by revealing how the dinosaurs spread, how fast they moved and what directions they moved in through time.  The dinosaurs exploded out of South America in a frenzy of movement to cover the planet.  It was during this time that diverse forms evolved and eventually led to species such as the fearsome Tyrannosaurus rex, Archaeopteryx (the earliest bird) and the gigantic, long necked Diplodocus.  This honeymoon period could not last forever though, and the dinosaurs eventually filled every available habitat on Earth.  There was nowhere new for species to move to, which may have prevented new species from arising, contributing to the dinosaurs’ pre-asteroid decline.  In essence, they were perhaps too successful for their own good.”

Using a Novel Statistical Analysis

The Reading University team developed a novel, statistical analytical method to help reveal where the ancestor of every dinosaur species lived.  This data was plotted onto a three-dimensional world map.  The analysis revealed that the dinosaurs spread virtually unchecked across the landmass of Pangaea at a rate of 1,000 kilometres (600 hundred miles), per million years.  They dominated every terrestrial habitat, across the globe as the supercontinent of Pangaea broke apart.

Sympatric Speciation

As the space left available for the Dinosauria to expand into was used up, the evolutionary driver for the development of new species might have changed.  The scientists conclude that dinosaurs initially diversified into new kinds driven by the expansion into new environments and habitats, but this driver for change was gradually replaced by sympatric speciation (new species evolving to exploit new niches within their existing environment).  This fundamental change in the way that dinosaurs evolved could have left them vulnerable to global catastrophes such as the extra-terrestrial impact event and the subsequent climate devastation that occurred some sixty-six million years ago.

Dinosaurs in Decline Many Millions of Years Before the End Cretaceous Mass Extinction

Earth impact event.

Cataclysmic impact event that led to the extinction of the dinosaurs.

Picture Credit: Don Davis (commissioned by NASA)

Dr Chris Venditti, evolutionary biologist at the University of Reading and co-author of the paper, commented:

“Early dinosaurs had a blank canvas and spread quickly across the devastated Earth, taking up every opportunity in their path.  Virtually every door was open to them as there was no competition from other species.  The inability of the dinosaurs to adapt rapidly enough as the Earth became full may explain why they were in decline prior to the asteroid strike, and why they were so they were so susceptible to almost total extinction when it hit.”

The scientific paper: “Dinosaurs Reveal the Geographical Signature of an Evolutionary Radiation” by Ciara O’Donovan, Andrew Meade and Chris Venditti published in Nature Ecology & Evolution.

Everything Dinosaur acknowledges the help of the University of Reading in the compilation of this article.

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6 02, 2018

When Did Flowers Evolve?

By | February 6th, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles|0 Comments

The Origin of the Angiosperms (Flowering Plants)

Scientists have concluded that the Angiosperms (flowering plants), probably evolved between 149 and 256 million years ago.  In a paper published in the academic journal “New Phytologist”, the researchers, which included scientists from the Chinese Academy of Sciences as well as Bristol University, conducted a comprehensive analysis of genetic data from 644 plant taxa.  This led them to conclude that, based on this dataset, the flowering plants that dominate the terrestrial flora of the world probably originated as early as the Late Permian or perhaps as recently as the Late Jurassic.

Arguing over the Origins of the Angiosperms

This new research suggests that flowering plants are not as old as suggested by previous molecular studies, nor as recent as the fossil record for Angiosperms reveals.  The team’s conclusions underline the power of using complementary studies based on molecular data and the fossil record, in conjunction with different approaches to infer evolutionary timescales, allowing the establishment of a better understanding of the evolution of organisms.

Ancient Buckthorn Flowers Preserved as Fossils

Two Buckthorn flower fossils.

Two fossilised Buckthorn flowers next to each other were discovered in shales of the Salamanca Formation in Chubut Province, Patagonia, Argentina.

Picture Credit: Nathan Jud/Cornell University (USA)

The “Abominable Mystery”

Darwin commented that the origin of flowering plants was an “abominable mystery”, the palaeogeographical origins of flowering plants , which today are represented by nearly 300,000 species remains a controversial area in palaeobotany.  Recently, Everything Dinosaur published an article documenting research that suggested that a downsizing in the genome of plants helped the Angiosperms become the dominant flora, but when the first flowering plants evolved has proved very difficult to establish.

To read the article on the Angiosperm genome study: Downsizing DNA Brings Success to Flowering Plants

Lead author of the scientific paper, Dr Jose Barba-Montoya (University College, London) explained:

“The discrepancy between estimates of flowering plant evolution from molecular data and fossil records has caused much debate.  To uncover the key to solving the mystery of when flowers originated, we carefully analysed the genetic make-up of flowering plants, and the rate at which mutations accumulate in their genomes.”

The Paucity of the Angiosperm Fossil Record

The fossil record for flowering plants, is very fragmentary.  Angiosperms appear to have radiated and diversified very suddenly around 125 million years ago.  The expansion of the flowering plants may have precipitated substantial changes in the fauna of the Cretaceous, this rapid change in fauna and flora is termed the “Cretaceous Terrestrial Revolution”, a short period in geological time when pollinators, herbivores and their predators underwent an explosive co-evolution.

The Rapid Evolution of Flowering Plants May Have Led to the “Cretaceous Terrestrial Revolution”

When did flowering plants evolve?

When flowering plants evolved there was a burst in evolution as symbiotic relationships formed.

Picture Credit: Bristol University

A Much Older Origin of the Angiosperms

Molecular-clock dating studies, however, have suggested a much older origin for flowering plants.  This  implies a cryptic evolution of flowers that has yet to be supported by fossil discoveries.  The discovery of wing scales from 200 million-year-old representatives of the Lepidoptera (moths and butterflies), hinted that flowering plants may have originated earlier than previously thought, after all, the adult butterflies and moths might well have fed on nectar from flowering plants.

To read Everything Dinosaur’s article about the ancient wing scales from Lepidoptera: Ancient Butterflies Flutter By

Professor Philip Donoghue (University of Bristol’s School of Earth Science), a senior author of the newly published  study, stated:

“In large part, the discrepancy between these two approaches [the fossil record and molecular dating] is an artefact of false precision on both palaeontological and molecular evolutionary timescales.”

Palaeontological timescales calibrate the family tree of plants to geological time based on the oldest fossil evidence for its component branches.  Molecular timescales build on this approach, using additional evidence from genomes for the genetic distances between species, aiming to overcome gaps in the fossil record.  Molecular clocks predict the age of organisms by looking at the rate of mutation between different genomes.

Senior author of the study, Professor Ziheng Yang (University College, London) added:

“Previous studies into molecular timescales failed to explore the implications of experimental variables and so they inaccurately estimate the probable age of flowering plants with undue precision.”

As a history of the evolution of the flowering plants, the fossil record which is particularly poor, is inadequate and conclusions based on the paucity of fossils are not possible.  The scientists compiled a substantial collection of genetic data for many flowering plant groups including a dataset of eighty-three genes from over six hundred taxa.  This evidence in conjunction with an extensive review of the fossil record allowed the team to plot the potential origins of the Angiosperms within upper and lower limits of geological time.

Co-author of the study, Dr Mario dos Reis (Queen Mary University, London) stated:

“By using Bayesian statistical methods that borrow tools from physics and mathematics to model how the evolutionary rate changes with time, we showed that there are broad uncertainties in the estimates of flowering plant age, all compatible with Early to Mid-Cretaceous origin for the group.”

Scientists may be some way off, being able to pin down the origins of flowering plants, more fossils, particularly of primitive Angiosperms are needed, but at least this new study has attempted to define the uncertainties associated with the evolution of this type of flora.

The scientific paper: “Constraining Uncertainty in the Timescale of Angiosperm Evolution and the Veracity of a Cretaceous Terrestrial Revolution” by J. Barba-Montoya, M. dos Reis, H. Schneider, PCJ Donoghue and Z. Yang published in the journal “New Phytologist”.

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

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5 02, 2018

The Tale of the Spiders with Tails

By | February 5th, 2018|Dinosaur and Prehistoric Animal News Stories, Main Page, Photos/Pictures of Fossils|0 Comments

Prehistoric Spiders Had Tails

A team of international scientists, including researchers from the University of Manchester, have announced the discovery of a new species of Cretaceous-aged spider.  The arachnid (Class Arachnida), which was preserved in amber from Myanmar (burmite), is helping palaeontologists to better understand the evolution of these very successful and diverse, eight-legged invertebrates.  This new spider species, named Chimerarachne yingi possessed a whip-like tail, a characteristic associated with ancestral forms and the most primitive types of extant spider, but the burmite has preserved a spider with this characteristic, that lived at least 250 million years after the first spiders evolved.

Photographs of the Spider Fossil with Accompanying Line Drawings

Chimerarachne yingi fossil and line drawings (dorsal and ventral views).

Chimerarachne yingi dorsal view (a) with accompanying line drawing and (b) ventral view with accompanying line drawing.

Picture Credit: The University of Manchester

Potentially a Transitional Fossil

The characteristics of today’s spiders are very well known.  These creatures have eight legs, several eyes and can spin silk, often to create cobwebs.  A “whip-like tail” is one feature that you would not normally associate with these particular creepy-crawlies.  The researchers, writing in the academic journal “Nature Ecology and Evolution”, conclude that the specimen might represent a transitional fossil, it possesses a tail (flagellum) and as such, the fossil may help scientists to better understand how the Arachnida evolved and diversified.

What is a Transitional Fossil?

Transitional fossils are defined as any fossil that demonstrates traits that are common to both an ancestral group and descendants.  Perhaps the best-known example is Archaeopteryx lithographica from the Late Jurassic of southern Germany.  The “Urvogel” shows both reptilian traits and characteristics of a bird, so it is regarded as a transitional fossil highlighting the evolution of one part of the Theropoda into modern Aves (birds).

A Fossil of the “Urvogel” Archaeopteryx Regarded as a Transitional Form

The Wellnhoferia Archaeopteryx.

The Wellnhoferia Archaeopteryx specimen.

Picture Credit: Pascal Goetgheluck

Chimerarachne yingi

The genus name comes from the Greek chimera – a mythical beast that was made up of parts from numerous animals.  The research team conclude that this new species belongs to an extinct group of spiders which were very closely related to true spiders.  What makes the fossil so unique, and different to spiders of today, is the fact it has a tail.  The discovery sheds important light on where modern spiders may have evolved from.  The Arachnida is an extremely successful class of invertebrates.  Spiders are the most diverse and numerous of all the arachnids, together spiders are grouped into the Order Aranae, some 47,000 living species have been documented.  Their evolutionary origins are obscure, but the first spiders may have evolved in the Late Devonian.  Over hundreds of millions of years, they have evolved several key innovations found only in this group.  These include spinnerets for producing silk for webs (as well as for other purposes like egg-wrapping), modified male mouthparts (pedipalps), unique to each species, which are used to transfer sperm to the female during mating, and venom for paralysing prey.

An Illustration of the Newly Described Cretaceous Arachnid Chimerarachne yingi

Cretaceous spider illustrated (Chimerarachne yingi).

Chimerarachne yingi illustrated (note the whip-like tail, the flagellum).

Picture Credit: The University of Manchester

The researchers, led by Bo Wang from the Chinese Academy of Sciences and including Dr Russell Garwood (University of Manchester), state that Chimerarachne yingi closely resembles a member of the most primitive group of modern living spiders – the mesotheles.  These spiders have a segmented abdomen unlike other groups found today, such as the mygalomorphs (Mygalomorphae), which include well-known spider species like tarantulas and funnel-webs.  Mesothelae spiders are restricted to south-east Asia, China and Japan today, but in the past they probably had a world-wide distribution (across the ancient super-continent of Pangaea).

Several Important Spider Characteristics

Chimerarachne yingi has several important spider features such as the spinnerets and a modified male pedipalp, but, outside of the obvious tail, it also demonstrates some anatomical differences. For instance, the male pedipalp organ of Chimerarachne appears quite simple, more like that of a mygalomorph spider than a mesothele spider.

Note the Long “Whip-like Tail” (Flagellum)

Ancient spider illustrated - Chimerarachne yingi.

Chimerarachne yingi illustrated (dorsal view).

Picture Credit: The University of Manchester

Dr Garwood explained:

“Based on what we see in mesotheles, we also would have expected the common ancestor of spiders alive today to have had four pairs of spinnerets, all positioned in the middle of the underside of the abdomen.  Chimerarachne only has two pairs of well-developed spinnerets, towards the back of the animal, and another pair that is apparently in the process of formation.”

Working Out the Evolutionary Tree of the Arachnida

The team studied the fossil using a range of different techniques.  One of Dr Garwood’s roles in the study was to help work out where this fossil sits in the evolutionary tree of the Arachnida.

Dr Garwood added:

“Perhaps the most interesting aspect of the new fossil is the fact that more than 200 million years after spiders originated, close relatives, quite unlike arachnids alive today, were still living alongside true spiders.”

Despite the beautiful state of preservation, the scientists are unable to state what function the tail might have had, or indeed, if this spider had a venomous bite.

Co-author of the study, published today, Dr Jason Dunlop (Museum Für Naturkunde in Berlin) stated:

“We don’t know whether Chimerarachne was venomous.  We do know that the arachnid ancestor probably had a tail and living groups like whip scorpions also have a whip-like tail. Chimerarachne appears to have retained this primitive feature.  Taken together, Chimerarachne has a unique body plan among the arachnids and raises important questions about what an early spider looked like, and how the spinnerets and pedipalp organ may have evolved.”

A Timescale Outlining the Proposed Evolution of the Chimerarachne

A timescale of Chimerarachne evolution.

A timescale showing the proposed evolutionary time scale for the Chimerarachne.

Picture Credit: The University of Manchester

Despite its appearance, the research team have concluded that C. yingi is not a direct ancestor of modern day spiders.  Spider fossils, although very rare, go back a long way into deep geological time.  Instead Chimerarachne belongs to an extinct lineage of spider-like arachnids which shared a common ancestor with the spiders, some of whom survived into the mid-Cretaceous of Southeast Asia.

By the Late Carboniferous Arachnids Represented a Diverse and Important Group of Terrestrial Predators

A carboniferous scene.

By the Carboniferous the insects and the mostly predatory arachnids were already highly diversified.

Picture Credit: Richard Bizley

The scientific paper: “Cretaceous Arachnid Chimerarachne yingi et sp. nov. Illuminates Spider Origins”, by Wang, B., Dunlop, J. A., Selden, P. A., Garwood, R. J., Shear, W. A., Müller, P. & Lei, X published in the journal Nature Ecology and Evolution.

Everything Dinosaur acknowledges the assistance of the University of Manchester in the compilation of this article.

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4 02, 2018

Mantellisaurus Drawing

By | February 4th, 2018|Dinosaur Fans, Everything Dinosaur Products, Main Page, Photos of Everything Dinosaur Products|0 Comments

Preparing for the CollectA Mantellisaurus Figure

Not long to wait now until the arrival of the first batch of new for 2018 CollectA prehistoric animal models (CollectA Prehistoric Life and CollectA Deluxe).  Our fact sheets for the new figures are complete and the scale drawings and illustrations that we commissioned have all been sorted out.  The picture (below), is our illustration of the new CollectA Prehistoric Life Mantellisaurus replica.  It is great to see a model being made of a dinosaur that was named in honour of Gideon Mantell.

An Illustration of Mantellisaurus (Dinosaur Scale Drawing)

Mantellisaurus scale drawing.

A Mantellisaurus scale drawing.

Picture Credit: Everything Dinosaur

The CollectA Mantellisaurus is depicted in a drinking pose, our drawing is a very close representation of the actual figure which is due to be in our warehouse soon.

The CollectA Mantellisaurus Dinosaur Model

CollectA Mantellisaurus dinosaur model.

CollectA Mantellisaurus drinking.

Picture Credit: Everything Dinosaur

We look forward to getting our hands on this new Ornithopod replica.

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3 02, 2018

Clevosaurus cambrica – Evidence of Island Dwarfism in the Ancient Triassic

By | February 3rd, 2018|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page|0 Comments

Fossil from South Wales Identified as New Triassic Species

In the 1950’s the Pant-y-ffynnon Quarry in South Glamorgan (Wales), provided a wide variety of vertebrate fossils giving palaeontologists an insight into the fauna of an ancient Triassic archipelago.  However, a comprehensive analysis of the fossil material was not carried out.  Scientists from the University of Bristol including an undergraduate student have undertaken a systematic review of the specimens and this has resulted in the naming of a new species of Rhynchocephalian.  The little reptile has been named Clevosaurus cambrica and this newly described animal hints at adaptive radiation for the Clevosaurs on the island chain.  In addition, since the researchers found no evidence of any reptiles in excess of two metres, they propose that the palaeofauna represents a possible example of insular dwarfism.  The concept of insular dwarfism (sometimes referred to as the “island rule” involves residents of islands with limited resources tending to become smaller overtime when compared to their mainland counterparts.

A Three-Dimensional Computer-generated Image of the Jawbone of C. cambrica

Clevosaurus cambrica jaw.

A three-dimensional image of the jaw of Clevosaurus cambrica.

Picture Credit: Bristol University

“Gloucester Lizard from Wales”

Emily Keeble’s final-year project for a degree in palaeontology at the School of Earth Sciences, (Bristol University) involved a reappraisal of the  Pant-y-ffynnon Quarry specimens.  Working alongside her course supervisors, the undergraduate was able to identify a new species of Clevosaurus, a type of reptile that was widespread across the supercontinent Pangaea in the Late Triassic.  Clevosaurus was named after “Clevum”, the Latin name for the city of Gloucester, as a number of species have been identified from this locality.  The trivial name “cambrica” honours Wales, where the fossil quarry is located.

In the Late Triassic, the hills of South Wales and the south-western part of England formed an archipelago that was inhabited by early dinosaurs, crocodylomorphs distantly related to modern crocodiles and alligators along with representatives of the Sphenodontidae such as the Clevosaurs.  The once diverse and geographically reptile family – the Sphenodontidae is today, represented by the rare Tuatara (Sphenodon punctatus) which is limited to a few small islands off New Zealand.

Clevosaurus cambrica Would Have Looked Like a Tuatara

An adult male Tuatara.

Only one species and a sub-species represent the Sphenodontidae today.

Picture Credit:  New Zealand Tuatara Conservation Team

Commenting on the significance of her discovery, Emily said:

“The new species, Clevosaurus cambrica lived side-by-side with a small dinosaur, Pantydraco, and an early crocodile-like animal, Terrestrisuchus.  We compared it with other examples of Clevosaurus from locations around Bristol and South Gloucestershire, but our new beast is quite different in the arrangement of its teeth.”

C. cambrica has been identified based on some articulated bones and some isolated fragments.  An analysis of the teeth in the jaws provided evidence that this small reptile probably was an insectivore.  The shape of the teeth and their arrangement identified the fossil as a new species.

Professor Mike Benton, a co-author of the paper and one of Emily’s supervisors added:

“We were lucky to find quite a lot of the skeleton and Emily was able to scan the blocks and make 3-D reconstructions of the skull, neck, shoulder and arm region.”

Evidence of Insular Dwarfism

The researchers conclude that the archipelago held a relatively impoverished fauna, dominated by rhynchocephalians such as the Clevosaurs.  The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of Clevosaurs in the palaeo-archipelago.  Adaptive radiation is the term used to describe the evolutionary process whereby organisms diverge from a common ancestor to fill a multitude of different ecological niches, think of Darwin’s finches on the Galapagos Islands, for example.

Co-author of the paper and co-supervisor of Emily Dr Whiteside (Bristol University) explained:

“The dinosaurs, crocodiles, and lizards were isolated to some extent on their islands, and perhaps smaller ones were better at surviving in the changed ecologies of the islands.”

The scientific paper: “The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures, South Wales, UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)” by Keeble et al published in the Proceedings of the Geologists’ Association.

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

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2 02, 2018

A Customised Schleich Psittacosaurus

By | February 2nd, 2018|Dinosaur Fans, Everything Dinosaur Products, Main Page, Photos, Photos of Everything Dinosaur Products|0 Comments

Schleich Psittacosaurus Gets a Makeover

At Everything Dinosaur, we are always keen to receive pictures from our customers of their model collections.  Many of the models and figures are displayed in dioramas and prehistoric scenes and it always amazes us when we see these fantastic creations.  We have concluded that there are a lot of very talented people who collect prehistoric animals.  Take for example, Elizabeth, an enthusiastic collector who commissioned Martin Garratt of UMF Models to customise her recently purchased Schleich Psittacosaurus figure.

The New for 2018 Schleich Psittacosaurus Dinosaur Model

Schleich Psittacosaurus (2018).

New for 2018, the Schleich Psittacosaurus dinosaur model.

Picture Credit: Everything Dinosaur

The new for 2018 Schleich Psittacosaurus has a lot going for it.  The pose is quite dynamic and the model has plenty of carefully crafted skin texture.  Schleich deserve considerable credit for creating a figure that reflects the latest scientific thinking when it comes to this early member of the Cerapoda.  Martin Garratt was able to repaint this little dinosaur and he has produced a beautiful diorama influenced by the recently published research into Psittacosaurus that indicated that this forest dweller probably had countershading to help to keep it safe.

The Customised Schleich Psittacosaurus Model

Customised Schleich Psittacosaurus.

A stunning Schleich Psittacosaurus dinosaur diorama.

Picture Credit: Marilyn (UMF Models) by permission of dinosaur model collector Elizabeth

Psittacosaurus and Countershading

Everything Dinosaur team members have been lucky enough to have viewed up close the remarkable fossil specimen that formed the basis of the research into the colouration of Psittacosaurus.  The study was published in 2016 in the academic journal “Current Biology”.  The authors of the paper, including researchers from the University of Bristol, concluded that this plant-eating dinosaur was light underneath but darker on its back.  This pattern is known as countershading and is a seen in a number of animals today.  To help illustrate the team’s conclusions, talented palaeoartist and model maker Bob Nicholls was asked to create a life-sized model of the creature so that the effectiveness of the camouflage could be tested.

Psittacosaurus Demonstrates Countershading

Psittacosaurus model in the Bristol Botanic Garden.

Psittacosaurus photographed in the Bristol Botanic Garden.

Picture Credit: Jakob Vinther

To read our article on the research: Calculating the Colour of Psittacosaurus

Dioramas and Dinosaur Research Coming Together

It is great to be able to view a customised dinosaur model that has been influenced by actual scientific research.  Ironically, thanks to copious fossil specimens from Asia, the Psittacosaurus genus is perhaps, the most studied of all the dinosaur genera.  Martin’s composition certainly mirrors the very latest thinking with regards to this two-metre-long dinosaur.

The Psittacosaurus Model with Carefully Selected Foliage to Mimic an Early Cretaceous Forest Environment

Schleich Psittacosaurus diorama by Martin Garratt.

The Schleich Psittacosaurus diorama.

Picture Credit: Marilyn (UMF Models) by permission of dinosaur model collector Elizabeth

The Skilfully Painted Replica Reflects Scientific Research into Countershading in the Dinosauria

Schleich Psittacosaurus diorama.

The Schleich Psittacosaurus dinosaur diorama.

Picture Credit: Marilyn (UMF Models) by permission of dinosaur model collector Elizabeth

Our thanks to Elizabeth for giving us permission to post up Martin Garratt’s work and for allowing us to publish Marilyn’s photographs.  Elizabeth tells us that she has more pictures of this excellent and beautifully composed diorama and we look forward to being able to put these on-line too in the very near future.

The Countershading Concept Demonstrated in a Dinosaur Diorama

Schleich Psittacosaurus dinosaur diorama.

A view of the Schleich Psittacosaurus dinosaur diorama.

Picture Credit: Marilyn (UMF Models) by permission of dinosaur model collector Elizabeth

To view the new for 2018 Schleich models as well as the rest of the Schleich range available from Everything Dinosaur: Schleich Prehistoric Animal Models

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