Category: Dinosaur and Prehistoric Animal News Stories

Out of Africa – Earlier Than Thought?

DNA Analysis Hints at Earlier Exodus of Modern Humans from Africa

A number of scientific papers have been published this week, most notably in the journal “Nature”, which discuss the thorny issue of how our species spread across the world.  Studies of modern human genomes from populations around the globe hint that there may have been an earlier human migration out of Africa, however, the evidence for this earlier migration remains controversial.  Understanding how and when our species migrated out of Africa and spread around the planet, reaching far-flung destinations such as Australasia, is still some way off.  Rather than clarify and unify theories, genetic studies seem to have muddied the waters somewhat.

A Native of Papua New Guinea – New Research Indicates A Very Ancient Human Ancestry

A Papuan tribesman.

A native of Papua New Guinea.

Picture Credit: Eric Lafforgue

Out of Africa

For decades, palaeoanthropologists argued over the origins of our species.  Did Homo sapiens originate from Africa or did we evolve from hominins that had spread across Europe, the Middle East and Asia much earlier?  Whilst most scientist now agree that Africa was the “cradle of mankind”, skeletal remains from various locations and new research into ancient climates, particularly the prehistoric climate of the Arabian peninsula, hinted that modern humans may have migrated out of Africa earlier than 60,000 years ago.  Certainly, the migration of modern hominins (and we include Neanderthals and the enigmatic Denisovans within this group), seems to be much more complicated than previously thought.  Fluctuating global climates allowed a number of migrations to take place with different species of people occupying different areas and indeed mixing at various points in our short history.  Our family tree resembles a very gnarled and twisted sapling.

To read a related article that looks at how changing climates in the Arabian peninsula may have had an impact on human migration: Out of Africa and into Arabia

Five Hundred Human Genomes Analysed (Almost)

Most non-Africans can trace their heritage back to a group of humans that left Africa around 60,000 years ago.  However, the study of almost five hundred human genomes (483 to be precise, from 148 world-wide populations), undertaken by scientists at the Estonian Biocentre has found traces of a much earlier “Out of Africa” human migration.  Faint traces of an earlier human migration were recorded in the DNA of the people of Papua New Guinea, but this study suggests that these earlier human pioneers all but vanished, so it does not alter drastically the prevailing theories as to the ancestors of the majority of us.  The researchers suggest that a genetic signature representing around 2% of the genome in present-day Papuans originates from an earlier and largely extinct expansion of anatomically modern humans out of Africa.  This data, together with fossil evidence and a recently published paper indicating a genetic mixing of Neanderthals and modern humans predating the main Eurasian expansion* contributes to the growing evidence to support the presence of our species outside Africa earlier than 75,000 years ago.

The paper published in the journal “Nature” and available as a pdf: “Genomic Analyses inform on Migration Events during the Peopling of Eurasia”.

Attempting to Map Human Migration out of Africa – When Did this Take Place?  How Many Times?

Ancient hominin skull.

Many experts believe that the ancestors of people alive today evolved in Africa and then colonised the world, but when did this take place?

Doctor Luca Pagani, lead author of the paper stated:

“All the other Eurasians we had were very homogenous in their split times from Africans.  This suggests most Eurasians diverged from Africans in a single event… about 75,000 years ago, while the [Papua New Guinea] split was more ancient, about 90,000 years ago.  So we thought there must be something going on.”

Same Edition of “Nature” Different Conclusions

In another paper, also published in “Nature” a team of scientists including researchers from the Estonian Biocentre (such as an author of the first paper – Mait Metspalu), as well as scientists from the Harvard Medical School and the New York Genome Centre, along with colleagues from a number of other institutions, came to a slightly different conclusion.  In this study, 300 genomes from 142 different populations were analysed and evidence was found of early splits in the populations within Africa, along with a single migration event that gave rise to non-African humans.  However, in this paper, no substantial evidence of an early (pre-60,000 years ago), African exodus was identified in the genomes of Papuans and other related populations such as of those groups that make up the Aboriginal race of Australia.  This team of scientists conclude that if, the genetic legacy of a more ancient migration survives in these populations, it cannot comprise more than a tiny portion of the entire genome.

The paper: “The Simons Genome Diversity Project: 300 Genomes from 142 Diverse Populations”.

Early Humans Exploring a New Potential Home

A group of early humans exploring a new landscape.

Homo sapiens originated in Africa but spread throughout the world.

A Third Study – Similar Conclusion

Papers on human ancestry must be a bit like buses.  You wait a while and nothing and then three come along at once.  In a third paper, also published in “Nature”, a study of the genomes of the Aboriginal race of Australia by researchers from the Centre for GeoGenetics, the Denmark Natural History Museum affiliated to the University of Copenhagen, along with colleagues from a number of other institutions including the Max Planck Institute, University College London and (once again), Mait Metspalu of the Estonian Biocentre, a similar conclusion to paper two is reached.  That, if there was an earlier human migration, then it is represented by only a tiny portion of the genome of living people from Oceania and Australia.

The title of this paper: “A Genomic History of Aboriginal Australia”.

Professor David Reich (Harvard Medical School) and a member of the Simons Genome Diversity Project that published the second paper summarised the research as follows:

“In our paper, we exclude more than about 2% ancestry in Australians, Papuans, and New Guineans from an early dispersal population, and our best estimate is 0%.  I am a bit concerned that poorly modelled features of the methods used by Pagani and colleagues [“Genomic Analyses inform on Migration Events during the Peopling of Eurasia”] may have contributed to a false-positive signal of early dispersal ancestry in them.  However, an alternative possibility is that the truth is around 2%, and this might just be consistent with all three studies.”

Dr. Mait Metspalu, the scientist who figured in all three publications stated that although the other papers do not detect a definitive signature for an earlier African migration by anatomically modern humans, this idea is not rejected, so long as it just contributes to a tiny portion of the genome in people alive today.

We leave it to the esteemed Professor Chris Stringer from the London Natural History Museum for the final word (for the moment), on this aspect of human ancestry.

Professor Stringer explained that the analysis undertaken by the Simons Genome Diversity Project and those scientists who studied the genome of the indigenous Australians favour the theory of a single migration event out of Africa less than 80,000 years ago giving rise to all living non-Africans.  In contrast, the paper with Doctor Luca Pagani as lead author, supports the idea of an additional and earlier modern human migration out of Africa more than 100,000 years ago, genetic traces of this earlier exodus can be found in Papuans, et al.

Tying It All in with the Human Fossil Record

There is certainly fossil evidence to indicate that our species (H. sapiens) was living outside Africa in the Near East, the Middle East and indeed elsewhere more than 60,000 years ago.  However, the paucity of the human fossil record, coupled with problems over dating bones and teeth in conjunction with a rather confusing picture involving interbreeding between several species of humans (Neanderthals, Denisovans and potentially yet another species of early human or two), has led to a rather muddled picture.  All three papers, although drawing slightly different conclusions, are helping to contribute to a greater understanding with regards to our own ancestry and we expect this lively debate to continue.  The evidence is likely to ebb and flow between the different scientific viewpoints, ironically, in a very similar pattern of backwards and forwards that most probably occurred with hominin species as they migrated in and out of various regions in response to climate change and other pressures.  A view articulated in a letter entitled “Human migration: Climate and the Peopling of the World”, co-authored by Professor Chris Stringer and coincidently also published in the latest edition of “Nature”.

*For the related article published in February which suggests that modern humans and Neanderthals may have interbreed 100,000 years ago: Mapping the Ancient Gene Flow between Ourselves and Neanderthals

Article on human migration into parts of Asia: Laos Man Skull Suggests H. sapiens Spread Rapidly into South-eastern Asia

The Food Chains of Messel

Fossil Preserves Snake ate Lizard, Lizard ate Beetle

Scientists from the Senckenberg Museum of Natural History have published a paper on a spectacular fossil from the famous Messel oil shales that shows evidence of a food chain preserved from the Eocene.  A fossil snake contains the preserved remains of its last meal, a lizard inside its stomach, astonishingly the exquisite fossil has also preserved evidence of the unfortunate lizard’s last supper too – a beetle.  The discovery of a tripartite fossil food chain is unique for this UNESCO World Heritage site and the only other tripartite food chain known in the fossil record dates from the Early Permian*, coincidentally, it also was found in Germany.

Who’s Eating Who?  Remarkable Three Party Trophic Chain (Food Web)

The Messel Tripartite Food Chain fossil.

The snake fossil which contains a lizard fossil which contains a fossilised beetle.

Picture Credit: Dr. Krister Smith (Senckenberg Museum of Natural History)

Scientists from the Senckenberg Museum of Natural History in collaboration with colleagues from Argentina were able to study this “Russian Doll” of a fossil, that dates from around 48 million years ago and gain new information about the diets of these ancient creatures.  For example, the twenty centimetre long lizard, identified as Geiseltaliellus maarius, is only known from the Messel shales.  Specimens found to date with preserved stomach contents, only had plant remains within the body cavity, this new research indicates that G. maarius was not entirely herbivorous, insects such as beetles were also on the menu.

Commenting on the study, published in the Museum’s scientific journal, Doctor Krister Smith, one of the authors of the paper stated:

“In the year 2009, we were able to recover a plate from the pit that shows an almost fully preserved snake. As if this was not enough, we discovered a fossilised lizard inside the snake, which in turn contained a fossilised beetle in its innards!”

A Magnified View of the Snake Gut with Line Drawings Indicating the Presence of Other Fossil Specimens

Tripartite food chain in Messel fossil.

The orange represents the lizard fossil, the blue the beetle remains.

Picture Credit: Dr. Krister Smith (Senckenberg Museum of Natural History)

The picture above shows the bones of the snake outlined with the lizard shown in orange (skull to the left of the picture), the blue shape in the lizard gut indicates the fossilised remains of the lizard’s last meal- a small beetle.  Unfortunately, the scientists were not able to identify the beetle genus.  The way in which the lizard remains were overlapped by the ribs of the snake prove that the body of the little reptile was definitely inside the snake when the snake, identified as a type of early constrictor (Palaeopython fischeri), met its own demise.

There was an Old Lady who Swallowed a Fly…

This beautifully preserved fossil specimen reminds team members at Everything Dinosaur of the song “there was an old lady who swallowed a fly”.  For the scientists, the Palaeopython specimen provides a new insight into the feeding habits of these Eocene snakes.  The snake fossil measures around 89 centimetres in length, but adult Palaeopythons exceeded two metres in size and they were amongst the largest terrestrial predators known from the Messel shale biota.  Just like modern constrictors and pythons, the authors suggest that the diet of these snakes changed as the animals got bigger.  The juvenile Palaeopython represented here (specimen number SMF ME 11332), may have fed on small rodents and lizards, whilst the adult snakes may have taken larger vertebrates such as young Propalaeotherium (an ancestral horse).

Based on an assessment of the degree of preservation of the lizard’s remains when compared to digestive speeds in extant snakes, the researchers conclude that the snake died within 48 hours of consuming the lizard.  That’s a remarkable insight considering the age of the fossil itself (approximately 48 million-years-old).

The scientific paper: “Fossil Snake Preserving Three Trophic Levels and Evidence for an Ontogenetic Dietary Shift”.

Early Permian Trophic Chains

* The first direct evidence of a three-level vertebrate trophic chain was published in the “Proceedings of the Royal Society Biology” in January 2008.  The fossilised remains of a species of Xenacanthiformes freshwater shark (Triodus sessilis) contained the remains of two ancient amphibians (Archegosaurus decheni and Cheliderpeton latirostre) preserved within its gut.  The C. latirostre specimen contained the remains of a small fish, inside its digestive tract.  The small fish was identified as a juvenile Acanthodes bronni.

Xenacanthiform (T. sessilis) with Ingested Prey Items

Xenacanthiform ate amphibians which ate fish.

Three level trophic levels in Early Permian fossil.

Picture Credit: Proceedings of the Royal Society Biology

The picture above shows the siderite concretion that preserves the remains of the freshwater shark and evidence of a three-level food chain from the Early Permian of south-western Germany.  Below the fossil specimen photograph is a line drawing that highlights the material representing the shark as well as the fossils of two ingested Temnospondyl larvae.  One of the amphibian fossils contains the preserved remains of its last meal, a small fish (acanthodian).

Illustrating an Early Permian Food Chain

Fish east amphibians which ate fish.

Xenacanthiform eats amphibians which in turn consumed fish.

Picture Credit: Proceedings of the Royal Society Biology

The illustration above depicts the three level trophic food chain.  Its a question of fish eats amphibian which ate fish!

Early Humans and their Ancient Fish Hooks

World’s Oldest Fish Hooks Found on Okinawa

The largely volcanic island of Okinawa, south of the Japanese mainland has provided the earliest known evidence of early humans using fish hooks.  Ancient fish hooks, skilfully carved from snail shells are amongst the artefacts discovered in a limestone cave (Sakitari Cave).  Archaeologists have stated that these fish hooks and other finds demonstrate the importance of adapting to maritime ecosystems as it permitted the spread of our species across the Pacific.

Ancient Fish Hooks Provide Clues to Human Expansion in the Late Pleistocene

Ancient fish hooks.

Ancient fish hooks from a limestone cave on the island of Okinawa.

Picture Credit: M. Fujita et al (Proceedings of the National Academy of Sciences)

The island of Okinawa lies between the mainland of Japan and Taiwan, at roughly three times the size of the Isle of Wight, it might be thought that this location would have been a very suitable habitat for human habitation, but the researchers, writing in the “Proceedings of the National Academy of Sciences”, suggest that this geographically isolated island may only have been occupied for part of the year, permitting early humans to exploit a seasonal food source.  In truth, Okinawa would have been a relatively inhospitable place for early settlers.  Fossil finds indicate that there were just a handful of kinds of large, terrestrial mammals on the island that could have acted as a source of meat.  There were two species of dwarf deer and wild boars.  Okinawa has virtually no raw materials that would have suited the technological demands of early humans, as a result, a number of researchers have hypothesised that the islands that make up this Japanese archipelago were too small for sustained occupation by Palaeolithic people.

The discoveries made by Japanese archaeologists including scientists from the Okinawa Prefectural Museum and Art Museum, along with colleagues from the University of Tokyo, have helped to “fill in a gap”, plotting the migration of Late Pleistocene humans across the western Pacific.

Charting the Spread of Humanity in the Western Pacific

A map charting the movement of humans in the Pacific (Pleistocene).

Pleistocene migration of humans across the Pacific.

Picture Credit: M. Fujita et al (Proceedings of the National Academy of Sciences)

Sakitari Cave lies more than a mile from the present coastline of south Okinawa, however, when the fish hook makers visited the island, sea levels were lower and the cave would have been located more than two and a half miles from the sea.  The archaeologists were able to successfully carbon date layers in the cave which indicate successive human occupation extending back to 35,000 to 30,000 years ago.  It is thought that maritime adaptation was one of the essential factors that enabled modern humans to spread all over the world.  The lack of clear data provides only a patchy picture of how humans moved into new parts of the world during the Late Pleistocene Epoch.  This new study of the well-stratified layers in Sakitari Cave, lends support to the idea that early modern humans were more advanced in their maritime technology than previously thought.  The finished and unfinished fish hooks, which had been carved from snail shells, have been calculated to be between 22,380 and 22,770 years old (radiocarbon dating of the carbon from the charcoal layer in which the fish hooks were found).  Other finds include marine molluscs as well as an abundance of freshwater mollusc shells, a potential grind stone and stone flakes along with a tooth and fragmentary human remains including bones representing an infant.

Finds from Sakitari Cave

Finds including human fossils from Sakitari cave.

Artefacts from the cave on Okinawa.

Picture Credit: M. Fujita et al (Proceedings of the National Academy of Sciences)

Accounting for any margin of error within the dating assessment, these fish hooks are older than similar fishhooks found in East Timor (between 23,000 and 16,000 years old) and New Ireland in Papua New Guinea (20,000 to 18,000 years old).  The findings lend support to the idea that these early modern humans were more advanced with maritime technology than previously thought, and that they were capable of sustaining themselves on relatively small, geographically remote Pacific islands.

The persistent occupation on this relatively small, geographically isolated island, as well as the appearance of Palaeolithic sites on nearby islands by 30,000 years ago, suggest a wider distribution of successful maritime adaptations than previously recognised, spanning the lower to mid-latitude areas in the western Pacific coastal region.  It seems that fishing has been a part of human activity for a very, very long time.

The paper: “Advanced Maritime Adaptation in the Western Pacific Coastal Region extends back to 35,000 to 30,000 Years Before Present”.

To read an article about the East Timor artefacts including ancient fish hooks: Tuna Catching Prehistoric Fishermen (or women)

To read an article published in 2015 about research into human teeth found in Sri Lanka that suggests a highly adapted rainforest technology in Late Pleistocene humans: Those Highly Adaptable Ancestors

Calculating the Colour of Psittacosaurus

Colour, Camouflage and Countershading in Dinosaurs

It turns out that the little dinosaur Psittacosaurus (parrot lizard), was light underneath and darker on its back.  This colour pattern, known as countershading is a common form of camouflage in extant animals.  Scientists including researchers from Bristol University conclude this in a new study of a beautifully preserved Psittacosaurus specimen currently on public display at the Senckenberg Museum of Natural History in Germany.  The study has been published in the academic journal “Current Biology”.

Reconstructing the Colour of Psittacosaurus

Reconstructing countershading in Psittacosaurus.

Physical reconstruction of Psittacosaurus with original colour patterns.

Picture Credit: Jakob Vinther and Bob Nicholls

Knowing the potential colour of an animal gives clues to its probable habitat.  The research team postulate that this little herbivore lived in an environment with diffuse light, such as in a forest.  To test this idea, a three-dimensional model of this Early Cretaceous dinosaur was created, step forward the very talented Bob Nicholls who has made a number of prehistoric animal models before for various museums and exhibitions.

The specimen on display at the Senckenberg Museum of Natural History, most likely originates from the Yixian Formation of Liaoning Province, China.  The fossil was illegally exported from China, in violation of Chinese law, but was purchased by the German museum.

The Fossilised Skeleton of Psittacosaurus (Senckenberg Museum of Natural History)

Psittacosaurus dinosaur fossil.

Psittacosaurus, early Cretaceous (120 million years old), preserving skin with colour patterns, Senckenberg Museum, Frankfurt, Germany

Picture Credit: Jakob Vinther and Robert Nicholls

One of the authors of the new scientific paper, Dr. Jakob Vinther (School of Earth Sciences and Biological Sciences, Bristol University) stated:

“The fossil, preserves clear countershading, which has been shown to function by counter-illuminating shadows on a body, thus making an animal appear optically flat to the eye of the beholder.”

Behavioural ecologist and co-author of the study, Professor Innes Cuthill from the School of Biological Sciences, added:

“By reconstructing a life-size 3D model, we were able to not only see how the patterns of shading changed over the body, but also that it matched the sort of camouflage which would work best in a forested environment.”

Countershading  most likely served to protect Psittacosaurus, a facultative biped and a member of the bird-hipped dinosaur group (Ornithischians), against predators that use patterns of shadow on an object to determine shape, just as we humans do.

Dr Vinther realised that structures previously thought to be artefacts or dead bacteria in fossilised feathers were actually “melanosomes,” small structures that carry melanin pigments found in the feathers and skin of many animals.  In some well-preserved specimens, such as the Psittacosaurus the researchers worked on in the new study, it is possible to make out the patterns of preserved melanin without the aid of a microscope.
Professor Cuthill and colleagues at Bristol had also been exploring the distribution of countershading in modern animals.  But it was no easy matter to apply the same principles to an extinct animal that had been crushed flat and fossilised.  To explore this idea further they teamed up with local palaeoartist, Bob Nicholls in order to reconstruct the remarkable fossil in to a physical model which, they say, is the most scientifically accurate life-size model of a dinosaur with its real colour patterns.

Days of careful studies of the fossil, taking measurements of the bones, studying the preserved scales and the pigment patterns, with input on muscle structure from Bristol palaeontologists Professor Emily Rayfield and Dr Stephan Lautenschlager, led to months of careful modelling of the dinosaur.
Bob Nicholls explained:

“Our Psittacosaurus was reconstructed from the inside-out.  There are thousands of scales, all different shapes and sizes, and many of them are only partially pigmented.  It was a painstaking process but we now have the best suggestion as to what this dinosaur really looked like.”

In order to investigate what environment the psittacosaur had evolved to live in, Dr Vinther, Bob Nicholls and Professor Cuthill took another cast of the model and painted it all grey.  They then placed it in the Cretaceous plant section of Bristol Botanic Garden and photographed it under an open sky and underneath trees to see how the shadow was cast under those conditions.  By comparing the shadow to the pattern in the fossil they could then predict what environment the psittacosaur lived in.

Psittacosaurus in the Bristol Botanic Garden

Psittacosaurus model in the Bristol Botanic Garden.

Psittacosaurus photographed in the Bristol Botanic Garden.

Picture Credit: Jakob Vinther

Dr Vinther stated:

“We predicted that the psittacosaur must have lived in a forest.  This demonstrates that fossil colour patterns can provide not only a better picture of what extinct animals looked like, but they can also give new clues about extinct ecosystems and habitats.  We were amazed to see how well these colour patterns actually worked to camouflage this little dinosaur.”

Psittacosaurus, which Professor Cuthill describes as “both weird and cute, with horns on either side of its head and long bristles on its tail”, lived in the Early Cretaceous of China and has been found in the same rock strata where many feathered dinosaurs have been discovered.  A number of species have been assigned to the Psittacosaurus genus, more species assigned to this genus than in any other genus of the Dinosauria.

Everything Dinosaur congratulates the researchers for this most insightful study and also acknowledges the efforts of the design team at the model maker CollectA for producing such an accurate representation of Psittacosaurus in the company’s dinosaur model range.

The Accurate CollectA Psittacosaurus Dinosaur Model

A typical psittacosaurid.

A typical psittacosaurid.

Picture Credit: Everything Dinosaur

The deposits that make up the Yixian Formation include evidence for a forest environment (based on wood and plant fossils).  The researchers say that they would now like to explore other types of camouflage in fossils and to use this evidence in understanding how predators could perceive the environment and to understand their role in shaping evolution and biodiversity.
The Scientific Paper: Vinther, J., Nicholls, R., Lautenschlager, S., Pittman, M., Kaye, T. G., Rayfield, E., Mayr, G. and Cuthill, I. C. 2016. 3D Camouflage in an Ornithischian Dinosaur. Current Biology.

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

Spiny Plants, Ungulates and the Savannah Habitat

The Evolution of Spiny Plants Holds Key to the Establishment of the Savannah

The continent of Africa contains a wide diversity of habitats, dominating the south, central part of Africa are the grasslands, the extensive savannahs that are home to a great diversity of iconic animals.  A team of international scientists writing in the academic journal “The Proceedings of the National Academy of Sciences United States”, have mapped the origins of the African savannah and concluded that the emergence of this ecosystem is, at least in part, down to the grazing habits of antelopes and their kin.

Ancient Bovids Influenced Habitat Formation in Africa

Rusingoryx illustrated

Honking to communicate in the hot savannah.

Picture Credit: Todd Marshall

The picture above shows an illustration of Rusingoryx atopocranion a wildebeest from the Pleistocene Epoch.  Grazing bovids and antelopes may have had a remarkable impact on the evolution of plant communities.

In a study that plotted flora/faunal relationships on a continental scale, the researchers identified which mammal browsers are most closely associated with spiny communities of trees.  The team were able to show that over the last sixteen million years or so, plants from unrelated taxa developed spiny defences against being eaten a total of fifty-five times.  This pattern of convergent evolution suggests that the arrival and diversification of bovids in Africa changed the rules for persisting in woody communities.  Contrary to current understanding, this new data indicates that browsers predate fire by millions of years as agents driving the origin of the African savannah.

The study was conducted in an unorthodox manner.  The researchers, which included biologists from McGill University (Montreal, Quebec, Canada), started by observing fauna and flora relationships in Africa today and then working backwards in time to the middle of the Miocene Epoch.

An Arms Race Between Plants and Animals

Many browsers like gazelles, delicately pick leaves off branches full of wicked-looking spines that are several centimetres long.  The scientists were able to uncover what happened in the past by mapping the distribution and evolution of the spiny plants on which gazelles and their relatives like to feed today.

A Gerenuk Antelope Browsing

A Gerenuk Antelope Browsing

A Gerenuk Browsing on Trees.

Picture Credit: Everything Dinosaur

Research team member, Jonathan Davies, (McGill University) commented:

“It’s been difficult to get a picture of how savannah ecosystems evolved because the conditions needed to preserve animal and plant fossils are very different from one another.  By working with the African Centre for DNA Bar-coding at the University of Johannesburg, we were able to sequence and compare DNA from nearly two thousand trees, and show that African plants only developed spines about fifteen million years ago. That was about the same time that a new type of mammal, antelope and their relatives, spread across the continent following the collision between the continental plates of Africa and Eurasia.”

Prior to this collision, the African continent had been dominated by the large, now extinct, ancestors of browsing elephants and hyrax.  These large herbivores would have bull-dozed trees and trampled vegetation, so spines were an ineffective defence against them according to the lead author of the study, Tristan Charles-Dominique (University of Cape Town).  However, antelopes and their relatives that arrived in Africa after the continental plate collision were highly efficient browsers, often using their delicate lips and prehensile tongue to remove leaves from branches.  It is likely that plants developed spines to defend themselves against these new plant “predators”.

Evolving a Spiny Defence Against Browsers

The study suggests a remarkable “arms race” between the trees and plant-eaters.  The arrival of new and efficient herbivores on the continent of Africa led to the evolution of more and more elaborate defences, including longer and longer spines.  One of the implications of this research is that the loss of large mammals like antelopes today, through human activities such as the bush meat trade, may have a substantial impact on the African landscape, with present day open savannahs being converted into thicket or brush.  Extensive forests may also make a comeback.

The Paper:  “Spiny Plants, Mammal Browsers and the Origin of the African Savannahs”.

Everything Dinosaur acknowledges the support of McGill University in the compilation of this article.

Walking with Dinosaurs Down at the Beach

Surprise Discovery of Dinosaur Tracks At Tourist Hot Spot

Fossilised footprints of a large Theropod dinosaur have been discovered at one of Australia’s most popular tourist beaches.  Broome’s Cable Beach is a very popular tourist area and hundreds of people visit this beautiful part of the Western Australian coast every day.  However, the pristine white sands hide a secret, it overlies a series of Cretaceous rock exposures where plant fossils and occasionally dinosaur footprints can be found.

One of the Three-Toed Dinosaur Prints Found at Cable Beach

Dinosaur footprint at Cable Beach (Western Australia).

One of the three-toed dinosaur tracks at Cable Beach.

Picture Credit: ABC Kimberley, Sophia O’Rourke

Ms Bindi Lee Porth was collecting shells at the beach last Sunday evening, when she literally stumbled across an amazing fossil find.  She noticed a strange shape in the rock and as she puts it herself:

“I just sort of brushed all the sand away and it’s revealed this beautiful, like a bird, foot.”

The Broome Coastline and Dinosaur Tracks

This part of the coast of Western Australia is renowned for its dinosaur tracks, that date from the Early Cretaceous (130 million years ago), a time when Australia was part of a much larger land mass (Gondwana) and it was nearer the South Pole.  Despite the high latitude, the climate was temperate to sub-tropical and many different kinds of dinosaurs roamed the land.

A Close Up of One of the Dinosaur Footprints

Dinosaur tracks found on beach.

A close up of one of the exposed dinosaur footprints.

Picture Credit: ABC Kimberley

Last year, Everything Dinosaur reported on efforts by University of Queensland researchers to map the extensive trackways using drones.

To read an article about this: Mapping the Dinosaur Heritage of Western Australia

The three-toed prints were exposed by the shifting sands, to have a set of tracks found so close to such a popular tourist location is quite a surprise and Ms Porth initially doubted what she had found, after all, casts of dinosaur footprints set in concrete have been created elsewhere along the coast in a bid to inform visitors about the ancient heritage of this part of Western Australia.  However, after having the trace fossils examined by Queensland University palaeontologist, Steve Salisbury, it was confirmed that these prints were genuine.

Dr. Salisbury commented:

“There have been tracks spotted in the Cable Beach area over the years, most of those are Sauropod tracks, but this is the first time we’ve become aware of there being another type of dinosaur track in that area.”

Doctor Salisbury with a Latex Cast of a Three-Toed Dinosaur Footprint

Taking a latex cast of a dinosaur footprint.

Dr. Steve Salisbury with a latex cast of an Australian dinosaur footprint.

Picture Credit: ABC News/Erin Parke

More Than One Type of Three-Toed Dinosaur

Dr. Salisbury’s trained eyes spotted something else unusual about the tridactyl prints.  Claws marks at the end of the toes can be clearly made out so these tracks were probably made by a meat-eater, but some of the tracks are subtly different, this suggests that more than one type of Theropod dinosaur is represented.  The Queensland University based scientist hopes to study the casts and in situ prints in order to determine more information about the dinosaurs that created them.

Using a simple hip to stride length formula, Dr. Salisbury has calculated that some of the prints were made by a dinosaur that had a hip height of around two metres.  A spokesperson from Everything Dinosaur commented that although it was not possible to give an accurate size estimate for a dinosaur based on these preliminary findings and more measurements would need to be taken, but as a rough approximation, you could be looking at a dinosaur around six metres in length.  A dinosaur that size would be about as big as Australovenator, a fearsome meat-eating dinosaur that lived some thirty million years or so after these tracks were made.

It may not be the biggest meat-eating dinosaur tracks ever found, the prints don’t represent the biggest Theropod known from Australia, but they do indicate that even in the most unlikely places, amazing fossils can be found.

To read an article that calls for more research to be done on the Western Australia dinosaur tracks: More Research Urgently Needed to Help Preserve and Protect Western Australia’s Trace Fossil Heritage

What Other Tracks Might Lie Under the Sand at Cable Beach?

A three-toed dinosaur footprint.

One of the dinosaur footprints from Cable Beach (WA)

Picture Credit: ABC Kimberley

Update on “Sibirosaurus”

General Media Picks Up Story of Giant Siberian Dinosaur

A  number of media outlets recently carried the story of the discovery of giant dinosaur fossil bones in Siberia.  There were lurid headlines such as “terrifying newly discovered dinosaur was the size of eight elephants” and claims that the Siberian fossils represented one of the largest animals ever to have walked on Earth.  Readers of this blog will note that we at Everything Dinosaur tend to try and avoid hyperbole and the dinosaur in question, most likely a new species of long-necked dinosaur (likely to be a Titanosauriform), had already featured in the weblog back in March 2015.  The dinosaur has been given the nickname Sibirosaurus, but it has yet to be formally scientifically described.  The Titanosauriforms are the largest single group of dinosaurs within the Macronaria, a clade of Sauropods united by their very large naris  (nasal openings) in their skulls, which in a number of genera are actually much larger than the eye socket (orbit).

Media Outlets Getting Excited by “Sibirosaurus”

Macronarian Titanosauriform dinosaurs.

An artist’s impression of a typical Macronarian dinosaur.

Picture Credit: Damir G. Martin

The fossils of this dinosaur have been slowly but surely extracted from a layer of extremely hard sandstone, located halfway up a cliff.  To read Everything Dinosaur’s 2015 article on the excavation work and to see pictures of the fossil dig site: Sibirosaurus Strides In

Work is Continuing on the Fossil Bone Preparation

Fossil preparation work in the laboratory.

A member of the lab team works on the fossil bones of a Macronarian dinosaur.

Picture Credit: Tomsk State University

The picture above shows one of the lab team members carefully removing the rock-hard matrix from a large bone (looks like a vertebra).   Claims in a number of newspapers that the dinosaur is a heavy as eight elephants (estimated weight up to fifty tonnes) and that these fossils represent one of the largest land animals known are a little premature, although it probably does represent a new species.  Dinosaur fossils have been found before in the sandstone rocks of the Kemerovo region of southern Siberia, but the fossils, in all probability do represent a species new to science.

A Piece of Dinosaur Fossil Bone at the Dig Site

A piece of dinosaur fossil bone.

A photograph of the Siberian dinosaur fossil bone at the dig site.

Picture Credit: Tomsk State University

The research is being conducted by Tomsk State University, St Petersburg State University and the Zoological Institute of the Russian Academy of Sciences.  A spokesperson from Everything Dinosaur commented that a formal research paper on this new dinosaur taxon will, in all likelihood be published next year.

Work has already been completed on the sacrum and it is hoped that these fossils along with foot bones from a Titanosauriform found in 1995 and likely to belong to the same species, will go on public display.

Although Fragmentary it is Likely a New Species of Titanosauriform will be Erected

Fossils of a new Titanosaur from Siberia.

Fossils of “Sibirosaurus” ready for cataloguing.

Picture Credit: Tomsk State University

3.7 Billion Year Old Microbial Structures?

A Rapid Emergence of Life on Earth?

When did life on Earth begin?  That is a very difficult question to answer, however, a team of scientists have published in the journal “Nature” this week suggesting that stromatolites (microbial colonies) existed in shallow marine environments as early as 3.7 billion years ago.  It’s all to do with waves and squiggles preserved in sedimentary strata from south-western Greenland.

Do These Wavy Lines and Structures Preserved in Ancient Sedimentary Rocks Indicate the Presence of Colonial Bacteria?

Are these wavy lines stromatolite fossils?

Evidence for ancient stromatolites?

Picture Credit: University of Wollongong

In the picture above the white scale bar represents 4 centimetres.

Although the paper is not without its controversy, if these waves and squiggles do turn out to be the ancient signatures left by mats of bacteria, then they would predate the previously oldest known fossils (from Australia) by some 200 million years or more.  Such claims are hotly contested, about as hot as the young Earth when the researchers (from a number of Australian institutions as well as from the UK), claim these stromatolites first existed.

The Isua Supercrustal Belt

The bleak, desolate uplands of south-western Greenland hold a secret.  The rocks here are the oldest surviving piece of the Earth’s surface.  As our planet continues to warm, so ice sheets shrink and slowly and surely, like the advance of geological time itself, new parts of our planet’s ancient crust are exposed.  This geological feature is called the Isua Supercrustal Belt (ISB).  Professor Martin van Kranendonk (University of New South Wales), specialises in the study of ancient life forms, dedicating his career to examining rocks for traces of Archean and Proterozoic life.  He and his colleagues hypothesise that the waves and cones seen in the ancient Greenland rocks are the traces of stromatolite stacks.

Researchers Exploring the ISB of Greenland

The Isua Supracrustal Belt of Greenland

The bleak and deserted part of south-western Greenland – on the hunt for ancient fossils.

Picture Credit: Picasa

Professor Kranendonk commented:

“We see the original unaltered sedimentary layers, and we can see how the stromatolite structures grow up through the sedimentary layering.  And we can see the characteristic dome and cone-shaped forms of modern stromatolites.”

If this is evidence of microbial colonies preserved in rocks some 3,700 million years old, then they predate by some 220 million years the previous most convincing and generally accepted evidence for the oldest life on Earth, the stromatolite fossils from the 3,480 million year old Dresser Formation of the Pilbara Craton, Australia.  These ancient rocks located in Western Australia are mostly volcanic in origin but the strata also preserves evidence of hydrothermal locations (hot springs), indicated by the presence of large quantities of the mineral barite.  These areas are associated with wrinkled structures, columns and cone shaped rocks, interpreted as evidence of stromatolite structures having existed within the hot springs and surrounding areas.

The ISB fossil material indicates the establishment of shallow marine carbonate production with biotic CO2 sequestration by 3,700 million years ago, close to the start of our planet’s sedimentary record.  If this is the case, then genetic molecular clock studies would push back the origin of life to before the Archaen Eon and into the Hadean Eon.  The Hadean Eon is the very oldest part of the Earth’s geological record.  It covers the period from our planet’s formation some 4.57 billion years ago to around 4 billion years ago (the start of the Archean Eon).  This suggests that life began on our planet when it was still being bombarded by extraterrestrial bodies, remnants from the formation of our solar system (the “Great Cometary Bombardment”).

Shark Bay Western Australia

Stromatolites can still be found today in various parts of the world (freshwater and marine environments).  For example, they can still be seen around the coast of Western Australia in a very saline body of water called Shark Bay.  The mushroom shaped structures found on the floor of the bay are the work of cyanobacterial communities.  Layers of mineral grains are glued together by the sticky, colonial bacteria.

Living Stromatolites (Shark Bay Western Australia)

Stromatolites at Shark Bay (Western Australia)

Stromatolite structures exposed at low tide (Shark Bay)

Picture Credit: sharkbay.org

To read an article from Everything Dinosaur published in 2010 about fossil evidence for the earliest animals found: Sponge-like Fossils May Be Earliest Animals

The Importance of Allkaruen

The Significance of the Pterosaur Allkaruen

A few days ago, Everything Dinosaur featured an article on this blog about a newly described Early Jurassic Pterosaur named Allkaruen koi.  We were subsequently emailed by one young dinosaur fan asking us to explain the significance of this fossil discovery.

Time to Get Excited About Pterosaurs – Learning Lots about Flying Reptiles

Ikrandraco Pterosaur fossil

White bar shows scale.

Picture Credit: Scientific Reports/Xiaolin Wang et al

The photograph above shows the fossilised remains of Ikrandraco avatar, a new species of Pterosaur described in 2014.

To read our recent article on the discovery of a new Pterosaur (A. koi) from Patagonia (Argentina): New Long-Tailed Pterosaur from Patagonia

Pterosaur Fossils are Exceedingly Rare

Fossils of flying reptiles are exceedingly rare, of the 130 or so genera described to date, most are known from only a few fragmentary fossils, mere scraps of bone and teeth.  The light, delicate, pneumatic bones of Pterosaurs rarely survive the ravages of time and the fossilisation process.  Most corpses, don’t even get buried, the chances are the carcase would have been scavenged long before it settled on a lake bed or the bottom of a shallow sea.  Therefore, the naming of a new flying reptile species is, in itself, a significant event.  For Allkaruen koi, even more so, as the rocks in southern Argentina where the fossilised bones were found indicate that this flying reptile lived around 180 million years ago.

A Beautiful Braincase

The new Pterosaur genus has been erected after careful study of the skeletal elements including an almost perfect, three-dimensionally preserved braincase.  Most Pterosaur fossils are crushed, distorted or compacted but not in this case, one of just a handful of very well-preserved flying reptile braincases known in the fossil record.  The braincase of Allkaruen shows a unique combination of characteristics of both the Rhamphorhynchoids (non-monofenestratan breviquartossans) and the Pterodactyloidea – let’s explain what this means.

The Pterosauria – the Order of reptiles that includes all these flying reptiles can be split into to distinct and very different groups.

  1. Formerly referred to as the Rhamphorhynchoids (as the very well known Rhamphorhynchidae family is included in this group), but now known to include a number of other Pterosaur families that evolved in the Triassic and the Jurassic, characterised by long-tails and a lengthy fifth digit.
  2. The Pterodactyloidea essentially the vast majority of known Pterosaurs, a Jurassic/Cretaceous radiation of flying reptiles with thin bone walls, relatively long metacarpals and much shorter tails.

So, in short, the researchers have a braincase from an Early Jurassic Pterosaur that shows features of both groups, the basal group and the later, short-tailed, long toed, thin bone walled Pterodactyloidea.  By studying the braincase of Allkaruen the palaeontologists can learn more about how the Pterodactyloidea evolved.  They can see how the brains of flying reptiles changed over time.

A Phylogenetic Assessment of Allkaruen Compared to Rhamphorhynchus and the Later Pterosaur Anhanguera

The phylogenetic position of Allkaruen.

Where within the Pterosauria Order does Allkaruen fit in?

Picture Credit: PeerJ

The researchers compared the changing shape and structure of Pterosaur brains, comparing Allkaruen with the brain anatomy of Rhamphorhynchus (representing the basal group), with the brain anatomy of a later Cretaceous Pterosaur Anhanguera, a representative of the short-tailed Pterodactyloidea.  Allkaruen could be described as a sort of “halfway house” between these two groups, a snapshot in Pterosaur evolution permitting scientists to gain “insights into the origin of the Pterodactyloid neurocranium and improve our understanding of the tempo and mode of Pterosaur evolution.”

The scientists mapped the various elements of the brain by comparing the braincases of these three Pterosaurs, from this information they could plot the evolution of the inner ear, essentially the balance organ, vital if you are going to spend a long time in the air.  The brain volume of Allkaruen is much bigger than that of Rhamphorhynchus and from this it can be inferred that Allkaruen was a more advanced animal capable of better co-ordinated flight and faster reactions than the Rhamphorhynchidae.  The cerebellum (show in yellow in the three brain diagrams included in the picture above), is much larger in Allkaruen than it is in Rhamphorhynchus.  The cerebellum in vertebrates is found towards the back of the brain it coordinates and regulates muscular activity.  A bigger cerebellum is another indicator that Allkaruen was a better flyer than the more basal Pterosaurs.  This and other evidence is helping palaeontologists to understand more about how the Pterosaurs evolved.

That’s why this fossil discovery is so important.

New Long-tailed Pterosaur from Patagonia

Allkaruen koi – Braincase and All

A team of international scientists including Leicester University’s David Unwin and Oliver Rauhut (conservator at the Bavarian Collection for Palaeontology and Geology), have announced the discovery of a new species of long-tailed Pterosaur from Patagonia (Argentina).  Writing in the academic journal “PeerJ”, the researchers were able to infer new information about how Pterosaurs adapted to an aerial lifestyle thanks to the three-dimensional preservation of the cranial material.  From this skull material, the team were able to gain fresh insights into the braincase and the structure of the inner ear.  The new species of Pterosaur will help palaeontologists to better understand differences between the primitive, primarily long-tailed “rhamphorhynchoids”, also known as non-pterodactyloids and the more derived and later, short-tailed pterodactyloids.

An Illustration of the New Pterosaur (Allkaruen koi)

Allkaruen Pterosaru illustration.

An illustration of the newly described Jurassic Pterosaur from Argentina called Allkaruen.

Picture Credit: Gabriel Lio

The Evolution and Radiation of the Pterosauria

The fossilised remains of this new Pterosaur come from the Cañadón Asfalto Formation, exposed in the northern/central Chubut Province of southern Argentina.  The fossil material came from a single bedding plane formed from freshwater limestone deposits, indicating that there was a large, inland body of water present.  The fossils were scattered although elements such as the mandible preserved a degree of articulation.  The rocks of the Cañadón Asfalto Formation had been thought to be about 162 million  years of age (Callovian to Oxfordian faunal stages – latest Middle to earliest Late Jurassic), however recent radiometric and biostratigraphical analysis suggests that these rocks might be much older.  Research published in 2013 (Cúneo et al), indicates an age range for this formation of between 183 and 165 million years (Toarcian to Bathonian faunal stages).

The genus name comes from the local Tehuelche dialect word “all” for “brain” and “karuen” which means “ancient”, in recognition of the superb three-dimensional preservation state of the fossil  skull.  The species name means “lake” in the Tehuelche language, reflecting the fact that the fossils were found in lacustrine deposits,

Fossils and Line Drawings of the Allkaruen koi Material

Fossils of the Jurassic Pterosaur Allkaruen

Fossils of the braincase, line drawings of the braincase along with drawings of the mandible and vertebrae.

Picture Credit: PeerJ

Two Main Types of Pterosaur

Pterosaurs have remarkable skeletal adaptations for life in the air and they were the first vertebrates to achieve powered flight.  Two major body plans have traditionally been recognised, rhamphorhynchoids (non-pterodactyloids) and the pterodactyloids.  These two types of flying reptile differ considerably in their general anatomy and also they exhibit very different head postures and neuroanatomy (nervous systems and the study of the brain).  Computerised tomography was employed to scan the uncrushed braincase that enabled the scientists to infer more information regarding the shape of the brain and the inner ear.  This study has provided new information on the origins of the highly derived neuroanatomy of pterodactyloids, as, until this new fossil discovery, only a few three-dimensionally preserved braincases of flying reptiles were known and these demonstrated a large morphological gap between the specimens.  The braincase of Allkaruen has helped fill in a portion of that gap to give scientists a better understanding of how the flying abilities of these reptiles evolved.

Dr. Diego Pol (CONICET, Museo Paleontológico Egidio Feruglio, Trelew, Chubut, Argentina) and corresponding author for the published paper stated: 

“Allkaruen shows an intermediate state in the brain evolution of pterosaurs and their adaptations to the aerial environment.  As a result, this research makes an important
contribution to the understanding of the evolution of all of Pterosaurs.”

A phylogenetic analysis was undertaken and Allkaruen is nested between monofenestratan breviquartossans (Rhamphorhynchidae) and derived pterodactyloids.  Given the age of the fossil and its phylogenetic affinities to Rhamphorhynchus and the Pterosaur known as Darwinopterus it has been suggested that this flying reptile had a long tail with a diamond shape rudder on the end of it.  Analysis of the cranium indicates that Allkaruen had two parallel crests on the top of its skull and it appeared to have teeth restricted to the middle and anterior (front) part of its jaws.  Although the exact diet of this Pterosaur is not known, given the context of the fossil material and the shape of the teeth, Allkaruen most likely fed on fish.

To read an article on the transitional fossil Darwinopterus: Darwinopterus – A Transitional Pterosaur

Dr. Oliver Rauhut has had a busy couple of weeks, he was also one of the principal authors of the scientific paper on the Early Jurassic meglosaurid Wiehenvenator.  To read about the “Monster of Minden”:Wiehenvenator albati – The Monster of Minden

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