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/Palaeontological articles

Articles, features and information which have slightly more scientific content with an emphasis on palaeontology, such as updates on academic papers, published papers etc.

26 05, 2019

Some Baby Dinosaurs Crawled Before Learning to Walk on Two Legs

By | May 26th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Mussaurus Switched from Four Legs to Two

A team of scientists, including researchers from the Royal Veterinary College based in London and Museo de La Plata and National Scientific and Technical Research Council (CONICET) located in Argentina, have collaborated to produce a report on how a Late Triassic sauropodomorph changed as it grew up.  The dinosaur in question Mussaurus patagonicus is an ideal candidate for dinosaur growth studies as it is known from numerous partial to nearly complete skeletons from hatchlings to fully grown adults.  Writing in the academic journal the researchers conclude that Mussaurus could only move on four limbs once born but switched to two legs as it grew up, just as our species switches from all fours to bipedal walking as we grow.

Scientists Looked at How the Centre of Mass Changed in the Body of Mussaurus to Work Out How it Walked

Plotting changes in Mussaurus as it grew.

Mussaurus specimens. (a, b) hatchling, (c) yearling and (bottom) adult.  Scale bars represent 5 cm (a), (b) 15 cm (c) and 100 cm in the adult animal representation.

Picture Credit: Scientific Reports

An Argentinian Sauropodomorph

Fossils of Mussaurus come from southern Argentina, at birth this dinosaur was only a few centimetres in length, but it reached its adult size in around eight years.  Essentially, this dinosaur went from weighing about 60 grams to weighing an estimated 1,300 kilograms with a body length of approximately 8 metres.  The research team conclude that it might have barely been able to walk or run on two legs at the age of one, but would have only committed to being bipedal once it reached adulthood.  This study has implications for the largest terrestrial vertebrates that ever lived as Mussaurus is regarded as an ancestral form of the later sauropods, giants like Apatosaurus, Mamenchisaurus and Giraffatitan, that were to evolve in the Jurassic.

The team scanned key fossils of Mussaurus into three-dimensional models, connected the bones into digital skeletons, and added soft tissue to estimate the shape of the body and its major segments such as head, neck, torso, tail and limbs.  These computer models were then used to estimate the location of the animal’s centre of mass, the point at which all weight can be assumed to act through.  This estimate enabled the scientists to then test whether different models representing different growth stages of Mussaurus patagonicus could have stood on two legs or not, because the centre of mass must be placed under the feet in such poses.

Identifying the Centre of Mass as Mussaurus Grew Up

Mussaurus Locomotion Study

Plotting the ontogeny of Mussaurus (a) hatchling, (b) yearling and (c) adult animal and the subsequent effect on centre of mass and locomotion.

Picture Credit: Scientific Reports

From Four Legs to Two

One of the authors of the scientific paper, Dr Alejandro Otero (CONICET) stated:

“Mussaurus switched from four legs as a baby to two legs by adulthood, much as humans do.  It is important to notice that such locomotor switching is rare in nature and the fact that we were able to recognise it in extinct forms like dinosaurs highlights the importance of our exciting findings.”

Professor John Hutchinson of the Royal Veterinary College, an expert in animal locomotion and co-author of the paper commented:

“We created the first 3-D representation of the major changes of body form and function across the growth of a dinosaur.  And we were surprised to learn that enlargement of the tail and reduction of the neck had more of an effect on how Mussaurus stood than how long its forelimbs were, which is what people used to think.”

Implications for Giant Dinosaurs

At around eight metres in length, Mussaurus was one of the largest dinosaurs in southern South America during the Late Triassic (estimated to be Norian faunal stage), however, during the Jurassic and Cretaceous much larger lizard-hipped dinosaurs would evolve from this lineage.  By improving our understanding about how some of the sauropodomorphs moved this type of research can provide insights into how much bigger plant-eating, long-necked giants walked.  When adult, dinosaurs such as Diplodocus and Brachiosaurus were very much quadrupedal, although it has been suggested that when very young some of these dinosaurs might have been able to rear up onto their hind legs to escape danger.*

Mussaurus Scale Comparison

Mussasaurus scale comparison.

Mussaurus scale drawing compared to an adult human and the skeleton of a typical Late Jurassic sauropod.

Picture Credit: Scientific Reports with additional annotation and information from Everything Dinosaur

* To read an article from 2011 that looked at the research into trace fossils from the western United States that hinted that some very young sauropods may have been able to run on just their hind legs: Facultative Bipedalism in Sauropods

The research team hope to build on this work as they plan to use computer models to replicate in greater detail how Mussaurus may have actually moved, such as how fast it could walk or run.

Everything Dinosaur acknowledges the assistance of a press release from the Royal Veterinary College (London) in the compilation of this article.

The scientific paper: “Ontogenetic changes in the body plan of the sauropodomorph dinosaur Mussaurus patagonicus reveal shifts of locomotor stance during growth” by Alejandro Otero, Andrew R. Cuff, Vivian Allen, Lauren Sumner-Rooney, Diego Pol and John R. Hutchinson published in Scientific Reports.

23 05, 2019

Ammonite Shell Preserved in Amber from Myanmar

By | May 23rd, 2019|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Ammonite Trapped in Nodule Helps to Date Myanmar Amber Fossils

This month has seen the publication of yet another remarkable paper detailing fossil discoveries found within amber nodules from northern Myanmar.  Writing an open article in the PNAS (Proceedings of the National Academy of Sciences of the United States of America), the researchers document a variety of terrestrial and marine invertebrates consisting of molluscs, insects, spiders and mites that have been preserved trapped in a piece of fossilised tree resin that dates from around 99 million years ago.  The organic remains consist of a mixed assemblage of intertidal and terrestrial floor organisms and suggests that the Cretaceous Myanmar forest was adjacent to a shifting and dynamic coastal environment.  The identification of the ammonite at the genus level has permitted the researchers to provide supporting evidence as to the age of the amber.  The ammonite shell is a juvenile Puzosia and its discovery adds weight to those academics proposing the dating of the amber to Late Albian–Early Cenomanian.

The Amber Nodule (Myanmar) with the Preserved Invertebrate Remains

Amber nodule preserves both terrestrial and marine organisms.

The amber nodule from Myanmar with a wide variety of both marine and terrestrial elements preserved within it.  The ammonite can be seen on the right of the picture, one of the gastropods is directly above it.

Picture Credit: PNAS

This is a rare example of a marine organisms associated with tree resin and also represents a rare instance of the dating of fossil tree resin using the remains of organisms trapped within an amber nodule.

X-ray-microcomputed Tomography (CT) Scans

The amber from northern Myanmar has provided palaeontologists with some fascinating fossils to study, including feathers, baby birds and even the partial tail of a feathered dinosaur.  The amber nodule in this study (BA18100), was obtained from an amber mine close to Noije Bum Village, Tanaing Town and it weighs a fraction over six grams.  Measuring 33 mm long, 9.5 mm wide and 29 mm high, it contains a diverse assemblage of at least forty individuals.  X-ray-microcomputed tomography (CT) scans was employed to help identify the fossil material.

Specimens from the Amber Nodule (BA18100)

A variety of invertebrates preserved in the amber nodule.

Mites, insects including flies and cockroaches and a spider preserved in the amber nodule.

Picture Credit: PNAS

The Ammonite Remains

The ammonite appears to be a juvenile and from a review of the septa (the complex boundary lines outlining the chambers), it has been identified as a member of the Puzosia genus.  This type of ammonite is known from the Cretaceous of the western Tethys Ocean, these fossils help to support the fossil record for this genus from the eastern Tethys region.  The ammonite has a diameter of around 12 mm and it appears to retain its original aragonite shell, that is the shell has not undergone any mineral replacement as expected during fossilisation.  The shell is almost complete, only the final body chamber is damaged as part of the umbilical wall extends beyond the fragmentary last part of the shell.

Views of the Ammonite Preserved within the Amber

Ammonite shell preserved in amber.

The juvenile ammonite has been identified as being from the Puzosia genus, it helps to date the amber nodule.  Scale bars equal 2 mm.

Picture Credit: PNAS

Marine Snail Shells (Gastropods)

The amber also contains the remains of marine snails.  Two of the gastropods have been identified as the genus Mathilda.  This type of marine snail is known from the western Tethys Ocean, but this is the first time that this marine snail genus has been recorded from the eastern Tethys.  The incomplete preservation and lack of soft body of the ammonite and marine gastropods suggest that they were dead and underwent abrasion on the seashore before entombment within the tree resin.

Views of the Marine Snail Shells (Gastropods)

Marine gastropods preserved in an amber nodule.

Four marine snails (gastropods) preserved in the amber of which two definitely represent the genus Mathilda.  Scale bars equal 1 mm.

Picture Credit: PNAS

Isopods

At least four isopods are also present.  Isopods are crustaceans and these creatures are known from terrestrial, brackish, freshwater as well as marine environments.  Unfortunately, the researchers were not able to identify the remains to the extent whereby it could be determined whether the preserved individuals came from the land or were aquatic.

Isopods Preserved within Amber

Isopods preserved in amber from Myanmar.

Four isopods and possibly three other specimens preserved in the amber that could be isopods but they are too badly damaged to be certain.  It is also not certain whether the isopods represent terrestrial, intertidal or marine forms.  Scale bars, 1 mm in A and C.  Scale bar, 0.5 mm in B and D.

Picture Credit: PNAS

How Did the Marine Assemblage End Up in the Tree Resin?

The scientists conclude that the tree resin fell onto the beach from coastal trees, for example araucarian conifers could have been growing close to the shore and the resin originated from one of these trees.  As it slid down the tree trunk it picked up terrestrial creatures and under gravity is moved across the sand picking up the shells on the beach.  It is remarkable that the tree resin survived the high-energy shore environment before being preserved as amber.  The authors, which include scientists from the Chinese Academy of Sciences suggest that resin ending up on the beach due to the proximity of the conifers could have been a relatively common event.  However, since this is the first time that an ammonite shell has been discovered entombed, the odds of fossilisation occurring and the material surviving long enough to turn into amber marks an exceptionally rare occurrence.

The dating of amber can be extremely difficult as these pieces can be reworked and redeposited.  The finding of an ammonite within a nodule, provides biostratigraphical dating support attesting to the 99-100 million-year-old estimate for these types of ancient tree resin from northern Myanmar.

The scientific paper: “An ammonite trapped in Burmese amber” by Tingting Yu, Richard Kelly, Lin Mu, Andrew Ross, Jim Kennedy, Pierre Broly, Fangyuan Xia, Haichun Zhang, Bo Wang, and David Dilcher published in the “Proceedings of the National Academy of Sciences of the United States of America.

22 05, 2019

Fossilised Mouse Reveals Evolutionary Secrets of Colour

By | May 22nd, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Ancient Mouse Reveals a Colourful Mammalian Heritage

Many mammals are brightly coloured, we have golden marmosets, red pandas and of course, black and white zebras.  The evolutionary use of colour within the Kingdom Animalia has long held the fascination of scientists, academics and philosophers.  This week, an international team of researchers led by members of The University of Manchester have published a new study revealing the evidence of colourful pigments in the remains of a prehistoric mouse.

The Fossilised Remains of a Prehistoric Mouse

The fossilised remains of a mouse.

The well-preserved remains of a Pliocene mouse used in the study.

Picture Credit: The University of Manchester

Writing in the journal “Nature Communications”, this work marks a major breakthrough in our ability to define colour pigments within the fossilised remains of long extinct animals and emphasises the role colour plays in the evolution of life on our planet.  The paper entitled “Pheomelanin pigment remnants mapped in fossils of an extinct mammal”, outlines the use of X-ray imaging on the 3 million-year-old fossils in order to unravel the story of key pigments in ancient creatures and demonstrates how we might recognise the chemical signatures of specific red pigments in extinct animals to determine how they evolved.

Professor Phil Manning, (University of Manchester), the lead palaeontologist involved in this study explained:

“The fossils we have studied have the vast potential to unlock many secrets of the original organism.  We can reconstruct key facets from life, death and the subsequent events impacting preservation before and after burial.  To unpick this complicated fossil chemical archive requires an interdisciplinary team to combine their efforts to crack this problem.  In doing this, we unlock much more than just palaeontological information.”

Co-author, Professor Roy Wogelius, from the University’s School of Earth and Environmental Sciences, added:

“This was a painstaking effort involving physics, palaeontology, organic chemistry, and geochemistry.  By working as a team, we were able, for the first time, to discover chemical traces of red pigment in fossil animal material.  We understand now what to look for in the future and our hope is that these results will mean that we can become more confident in reconstructing extinct animals and thereby add another dimension to the study of evolution.”

This exciting, collaborative effort from numerous scientific disciplines reveals that within fossils with exceptionally preserved soft tissues, evidence of black pigmentation can be identified, but furthermore, traces of the much more elusive red animal pigment may be found.  The chemical residue of black pigment, which colours such animals as crows, was first resolved by this team in a previous study nearly ten years ago.  However, the red pigment, characteristic of animals such as foxes and red pandas, is far less stable over geological time and proved much more difficult to detect.

Apodemus atavus Life Reconstruction

Apodemus atavus - mouse from the Pliocene helps reveal the evolution of pigmentation.

A life reconstruction of the mouse from the Pliocene – Apodemus atavus.

Picture Credit: The University of Manchester

Professor Wogelius went on to say:

“We had data which suggested red pigment residue was present in several fossils, but there was no useful data available to compare this to pigmentation in modern organisms.  So, we needed to devote several years to analysing modern tissue before we could go back and review our results from some amazing fossil specimens.  In the end, we were able to prove that detailed chemical analysis can resolve such pigment residue, but along the way we learned so much more about the chemistry of pigmentation throughout the animal kingdom.”

Shining a Light on Pigmentation Thanks to the Stanford Synchrotron Radiation Lightsource

To unlock the hidden data within the fossil material, the Manchester-based scientists collaborated with researchers at some of the brightest sources of light on the planet, using synchrotron radiation at the Stanford Synchrotron Radiation Lightsource (USA), and also at the Diamond Light Source (located in Oxfordshire), to bombard the fossils with intense X-rays.  It is the interaction of these X-rays with the chemistry of these fossils that enabled the team to be the first to recognise the chemistry of red pigmentation (pheomelanin), in fur from the exceptionally well-preserved remains of a mouse that scuttled about in the Pliocene Epoch (Apodemus atavus).

The key to the study was identifying trace metals incorporated by ancient organisms into their soft tissues and comparing these to the modes of incorporation into living species.  The chemistry shows that the trace metals in the mouse fur are bonded to organic chemicals in exactly the same way that these metals are bonded to organic pigments in animals with high concentrations of red pigment in their tissue.

In order to confirm the team’s findings, modern comparison standards were analysed by synchrotron radiation and by specialists in pigment chemistry based at the Fujita Health University in Japan.

A False Colour Image of the Fossilised Mouse

A false colour image of the fossil mouse.

A false colour image of the 3 million-year-old fossil mouse used in the red pigment study.

Picture Credit: The University of Manchester

Summarising the significance of this research Professor Manning stated:

“Palaeontology offers research that is more than relevant to our everyday life.  Information gleaned from the fossil record is influencing multiple fields, including; climate research, the burial of biowaste and radwaste, the measure of environmental impact of oil spills on living species with techniques developed on fossil organisms.  Whilst our research is firmly anchored in the past, we set our sights on its application to the future.”

The scientific paper: “Pheomelanin pigment remnants mapped in fossils of an extinct mammal” by Phillip L. Manning, Nicholas P. Edwards, Uwe Bergmann, Jennifer Anné, William I. Sellers, Arjen van Veelen, Dimosthenis Sokaras, Victoria M. Egerton, Roberto Alonso-Mori, Konstantin Ignatyev, Bart E. van Dongen, Kazumasa Wakamatsu, Shosuke Ito, Fabien Knoll & Roy A. Wogelius and published in Nature Communications

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

20 05, 2019

Sorting out Tiny Fossil Flies

By | May 20th, 2019|Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Phylogeny of Fungi-loving Flies Being Sorted

The fossils of dinosaurs and other huge vertebrates might grab the headlines but there is an enormous volume of research dedicated to examining the fossil record of some of the less high profile, but arguably more significant prehistoric creatures.  Take for example, the recent paper put together by researchers from the National Museums of Scotland and the Smithsonian Institution that helped resolve part of the family tree of the Diptera, essentially this is the Order of flies, part of a group of winged insects that could lay claim to being amongst the most successful animals to have ever existed.

The research focused on the fossils associated with one family of flies, the Bolitophilidae.  They are tiny and common in temperate forests across the Northern hemisphere and their larvae feed almost exclusively on mushrooms.  These little flies may not be very big, but the play a huge role in ensuring a balanced, healthy ecosystem.

A New Species of Eocene Fly Has Been Identified from Baltic Amber (Bolitophila rohdendorfi)

Eocene gnat fly preserved in Baltic amber (Bolitophila rohdendorfi)

Bolitophila rohdendorfi – new species of gnat fly identified from Baltic amber.

Picture Credit: National Museums of Scotland

The earliest fossil material associated with bolitophilids comes from Baltic amber and from contemporaneous amber found in Montana (Kishenehn Formation).  The fossilised tree resin has preserved the remains of individuals that had become trapped in sticky tree resin.  These fossils date from approximately 46 million years ago (Lutetian stage of the Eocene Epoch).  The fossilised flies look remarkably like their extant relatives, they look like small crane flies but they are, in truth a form of gnat.  The remarkable specimens entombed in the amber have allowed the scientists to make detailed observations helping to clarify the taxonomy and evolutionary history of this fly family.

Two New Species of Bolitophilid Fly Erected

These well-preserved fossils have allowed the scientists to erect two new species within the Bolitophilidae family.  The specimens from Montana have been named Bolitophila warreni and the Baltic amber fossils represent Bolitophila rohdendorfi.  Perhaps more significantly, these Eocene gnats have permitted scientists to revise the phylogeny of other ancient flies.  Fossils from the Lower Cretaceous of Mongolia and Transbaikalia had been placed in the Bolitophilidae family (subfamily Mangasinae) but their taxonomic position was controversial.  Thanks to this new research, the affinity of the Mangasinae within the Bolitophilidae has been confirmed.  In addition, a review of the fossil material has enabled a further two species of the fly genus Mangas to be erected, namely Mangas kovalevi and Mangas brevisubcosta both of which originate from the Lower Cretaceous of Khasurty in Western Transbaikalia.

Beautifully Preserved Lower Cretaceous Fly (Mangas kovalevi)

Mangas kovalevi fossils.

Mangas kovalevi, new species of gnat fly from Cretaceous of Transbaikalia.

Picture Credit: National Museums of Scotland

Linking Lower Cretaceous Flies to Upper Cretaceous Dromaeosaurs

Dinosaurs were plagued by flies, just like animals today, although members of the Bolitophilidae family would have been more interested in fungi than flesh.  However, there is a further link between these flies and a member of the Dinosauria.  The dromaeosaurid named Tsaagan mangas, which was scientifically described in 2006, its trivial name was also inspired by a legendary Mongolian monster, the same legendary beast that was the inspiration behind the name of the bolitophilid subfamily, the Mangasinae and the erection of the Mangas genus.

Everything Dinosaur acknowledges the assistance of a press release from the National Museums of Scotland in the compilation of this article.

The scientific paper: “Review of the Fossil Record of Bolitophilidae, with Description of new Taxa and Discussion of Position of Mangas kovalev (Diptera: Sciaroidea)” by Dale E. Greenwalt and Vladimir A. Blagoderov published in the journal Zoo Taxa.

18 05, 2019

Walking with Dinosaurs – How?

By | May 18th, 2019|Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Sauropods Had Fleshy Pads on Their Feet

A team of scientists led by researchers from the University of Queensland have concluded that giant, long-necked dinosaurs (Sauropoda), probably walked in a “high-heeled fashion”.  Their great weight was supported by a fleshy pad at the base of the foot, effectively cushioning the heel and helping to support their enormous weight.  Elephants also have a fleshy pad on their feet, it seems that these two types of terrestrial, giant tetrapods, although not closely related, evolved the same type of soft tissue pad supporting the elevated metatarsus, an example of convergent evolution.

An Anatomical Reconstruction of the Right Hind Foot of a Sauropod (Rhoetosaurus brownei)

The right hind foot of Rhoetosaurus brownei.

The right hind foot of Rhoetosaurus brownei in dorsal view.  The first four digits have been preserved although the fifth is missing (replaced by a cast).

Picture Credit: Jay P. Nair and Andréas Jannel (University of Queensland)

Sauropod Locomotion – The Biomechanics

How the sauropod foot worked is very poorly understood.  This is partly because there are not that many complete foot fossils to study (manus and pes in these quadrupeds), especially amongst early members of the group and there is no living equivalent of these long-necked giants around today, to provide scientists with anatomical comparisons.  The researchers from the University of Queensland in collaboration with colleagues from Monash University (Victoria), examined the foot and toe bones of Rhoetosaurus brownei in a bid to plot the biomechanics of sauropod locomotion.

At around twenty tonnes and with a body length in excess of fourteen metres, Rhoetosaurus was a very sizeable animal, but certainly not the biggest of the Sauropoda.  However, it is known from eastern Australia so its fossils were easy to access for the researchers and it is the earliest representative of sauropods known from Australia.  In fact, according to the press release from the University of Queensland, it is the only named Australian sauropod that dates from the Jurassic.  Conveniently, it is the only one from the Gondwanan Middle Jurassic that preserves an articulated foot.

A Model of Rhoetosaurus (R. brownei)

CollectA Rhoetosaurus model.

A model of the Middle Jurassic sauropod Rhoetosaurus brownei.  Whether this dinosaur could rear up onto its hind legs is speculative.

Picture Credit: Everything Dinosaur

Three-dimensional Modelling of a Dinosaur’s Foot

The scientists carefully analysed the foot bones and compared them to the foot bones of an African elephant (Loxodonta).   Lead author of the research, PhD student Andréas Jannel (University of Queensland), explained:

“Looking at the bones of the foot, it was clear that Rhoetosaurus walked with an elevated heel, raising the question: how was its foot able to support the immense mass of this animal, up to 40 tonnes?  Our research suggests that even though Rhoetosaurus stood on its tiptoes, the heel was cushioned by a fleshy pad.  We see a similar thing in elephant feet, but this dinosaur was at least five times as heavy as an elephant, so the forces involved are much greater.”

The researchers used physical models and computer simulations to map the posture and the range of motion of the foot bones.  The results generated permitted the team to model all the foot bone postures and from this it was deduced that some of these movements would have been restricted by soft tissue in life, but this soft tissue would have helped to support the animal’s great weight.

The team concluded that the in‐life plantar surface of the sauropod pes is inferred to extend caudally from the digits, with a soft tissue pad supporting the elevated foot bones, in essence, these terrestrial giants walked in a “high-heeled fashion”.  Furthermore, the plantar pad is inferred to play a role in the reduction of biomechanical stresses, and to aid in support and locomotion.  A foot pad may have been a key biomechanical innovation in early sauropods, ultimately resulting in a functionally plantigrade foot, which may have arisen during the Early to Middle Jurassic.  Although, these dinosaurs, like all other dinosaurs had a digitigrade or semi-digitigrade stance, the soft tissue pad changed their feet morphologically, so, these dinosaurs had a more plantigrade stance (not just walking on their toes).

This research into the locomotion of the biggest land vertebrates that ever lived has provided some intriguing insights, but the authors of the scientific paper admit that further mechanical studies are ultimately required to permit a more complete understanding of how these giants moved about.

Studies of Sauropod Tracks and Trackways Lend Support to Idea that these Animals Walked on Pads of Soft Tissue

The fossilised footprint of a Late Cretaceous Titanosaur.

Professor Shinobu Ishigaki (Okayama University of Science) provides the scale for the dinosaur print.  The track of a Titanosaur (Sauropoda).

Picture Credit: Okayama University of Science

The scientific paper: “Keep your Feet on the Ground”: Simulated Range of Motion and Hind Foot Posture of the Middle Jurassic Sauropod Rhoetosaurus brownei and its Implications for Sauropod Biology by Andréas Jannel, Jay P. Nair, Olga Panagiotopoulou, Anthony Romilio and Steven W. Salisbury published in the Journal of Morphology.

17 05, 2019

The Jurassic Angiosperm Gap

By | May 17th, 2019|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles|0 Comments

The Jurassic Angiosperm Gap

Today, the flora of the world is dominated by the angiosperms (flowering plants), they are the most diverse and widespread group of land plants comprising more than four hundred families, but their origin remains a mystery.  The fossil record for flowering plants is sparse, but there are numerous, unequivocal angiosperm fossils known from Cretaceous rocks.  Fossils of angiosperms from the Cretaceous appear abruptly and demonstrate a remarkable abundance of different forms.  The apparently rapid evolution of flowering plants in the Cretaceous was commented upon by Charles Darwin, the author of the ground-breaking “The Origin of Species”.  Darwin described the diverse Cretaceous-aged fossils of flowering plants when very few earlier flowering plant fossils were known as “a great abominable mystery.”

To read an earlier article (published in 2018), that looked at the puzzle of when angiosperms evolved: When Did Flowers First Evolve?

Fossils of Water Lilies (Nymphaeales) Are Known from the Cretaceous but when did the Flowering Plants Evolve?

A water lily in flower.

From the time of the Dinosaurs, but when did the angiosperms first appear?

Picture Credit: Everything Dinosaur

Molecular Clock Dating and Genome Analyses Indicate Origins Earlier in the Mesozoic

Molecular clock studies have frequently suggested an earlier origin for angiosperms in the Jurassic, or even potentially within the Triassic.  However, many studies have lacked extensive sampling, especially at the ordinal and familial levels.  Now, in a new scientific paper published in the journal “Nature Plants”, researchers from the Chinese Academy of Sciences have mapped and plotted a comprehensive angiosperm phylogeny, sampling nearly 3,000 chloroplast genomes from species representing all 64 known plant Orders and 85% of all the flowering plant families described to date.  This most intensive study of living flowering plants has been cross-referenced with the fossil record of angiosperms and indicates an origin of these types of plants in the Late Triassic (around 209 million years ago – Norian stage of the Late Triassic).

This earlier age for angiosperm evolution leaves a gap between the earliest fossils and the origins of flowering plants of almost 70 million years, roughly the length of the entire Jurassic period, the authors term this huge period of geological time as “the Jurassic Gap”.

Identifying “The Jurassic Gap” in the Angiosperm Lineage

The "Jurassic Gap" in the evolutionary history of flowering plants.

Identifying the angiosperm “Jurassic gap”.  If flowering plants originated around 209 million years ago, then there is a gap of some 70 million years in the fossil record which if filled in would plot the rise of this important group and their radiation.

Picture Credit: Nature Plants with additional annotation by Everything Dinosaur

Arising in the Late Triassic and Early Jurassic

The authors of the paper propose that the earliest lineages of flowering plants originated in the Late Triassic or Early Jurassic.  These early parts of the angiosperm family tree are represented (as expected), by a few species totalling no more than a couple of hundred taxa or so.  These early members of the angiosperm group include water lilies (Nymphaeales), the woody plant order Austrobaileyales, which contains star anise and the large shrub Amborella trichopodanative to the island of New Caledonia in the southwest Pacific Ocean, a plant which is regarded as the sister taxon to the remaining angiosperms.

The data generated by the scientists indicates that major diversifications subsequently occurred in the Late Jurassic and Early Cretaceous resulting in 99.95% of the extant diversity of flowering plants.  The relationships of the five major clades of this large diversification (core angiosperms) have long been difficult to determine and the researchers conclude that despite this extensive study, more work is required to resolve this aspect of flowering plant evolution.

Linked to the Rise of Insects – Symbiotic Relationships with Flowering Plants

If the first angiosperms arose in the Triassic, this corresponds with the timing of the evolution of several types of insects including katydids, crickets, alderflies and the common ancestor of the Lepidoptera (moths and butterflies).  However, the spectacular diversification of core angiosperms in the Jurassic and Early Cretaceous notably also coincides with the origin and evolution of the Phytophaga, arguably the most diverse radiation of plant-feeding beetles.  Their association with angiosperms has long been proposed to account for the apparent evolutionary success of the Phytophaga.  Furthermore, modern beetle diversity in general as well as other pollinators, including moths and butterflies, had their origins in the Cretaceous, which coincides with the rise of flowering plants to ecological dominance and the major diversifications of extant angiosperm diversity in the phylogeny as reported by the Chinese Academy of Sciences.

The Present-day Diversity of Beetles Could be Linked in Part to the Success of Flowering Plants

A beetle.

Soldier Beetle – the evolution and radiation of flowering plants is linked to the radiation of the Insecta – a result of the symbiotic relationship between many angiosperms and insects.

Picture Credit: English-Country-Garden.com

To read an article about ancient wing scales found in a drill core that suggests a Triassic origin for the Lepidoptera: Ancient Butterflies Flutter By

Why the Jurassic Gap?

One explanation put forward for the “Jurassic Gap” is that in the early days of flowering plant evolution, these plants were rare and thus the chances of any number becoming preserved as fossils were slim.  Another explanation proposed, is perhaps they occurred in habitats that were unsuitable for preservation such as forests.  Charles Darwin commented that it was “wretchedly poor conjecture” that angiosperms could have had a pre-Cretaceous history on a remote, but lost, island, meaning that all evidence of early flowering plants had been essentially wiped out.

A somewhat less exotic explanation is that the structures, flowers or fruits of early flowering plants were too small to now be confidently assigned to angiosperm lineages.  Perhaps, more fossils will be found to help plug the “Jurassic Gap”, but for the time being this period of seventy million years or so remains a mystery.

Everything Dinosaur acknowledges the assistance of a press release from the Chinese Academy of Sciences in the compilation of this article.

15 05, 2019

Fossil Hunting on Mars?

By | May 15th, 2019|Geology, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Fossil Hunting on Mars – Where to Look?

The second stage of the joint European and Russian ExoMars project is due to launch in 2020.  The first part of the mission involved an atmospheric probe designed to search for trace amounts of methane and other gases in the thin Martian atmosphere – evidence of there having been life on the planet in the past.  The results so far have been a little disappointing but, part two will continue the main aim of this programme, addressing the question as to whether or not we are alone in the universe.  A rover will explore the surface and crucially, it will collect samples with a drill down to a depth of two metres and analyse them onboard using sophisticated instrumentation.  Samples from beneath the surface of Mars are more likely to include biomarkers, as the thin atmosphere provides little protection from radiation and photochemistry, but could ExoMars be looking for evidence of life in the wrong place?

An Artist’s View of the ExoMars Rover on the Martian Surface

ExoMars Rover (2020)

Set to launch in 2020 the ExoMars expedition will include a sophisticated rover that will drill into the soil to test for past life.

Picture Credit: European Space Agency (ESA)

An Atlas of Volcanic Rock – On the Hunt for Extremophiles

Researchers at the Swedish Museum of Natural History (Stockholm),  have begun compiling an atlas of fossils in volcanic rock, to guide where and what to look for in the search for Martian life.  Most fossils are associated with sedimentary rocks and there are sedimentary rocks on the red planet (deposits formed in layers), either through the transport of material via water, with the assumption that in the ancient past, liquid water existed on the Martian surface, or via wind (aeolian) deposition.  However, igneous rocks dominate the geology of Mars and writing in the academic journal “Frontiers in Earth Science”, the scientists suggest that it is these igneous rocks that may harbour evidence of life.  Producing a guide to the microbial fossils found in volcanic rocks on Earth, can then assist the Mars exploration team in identifying suitable sites to hunt for Martian microbial fossils.

An Environmental Scanning Electron Microscope Image of Fossilised Fungi

Fossil fungal mycelium.

ESEM image of a fossil fungal mycelium with associated “cauliflower-like” microstromatolite formed by iron-oxidizing bacteria. From Koko Seamount, Pacific Ocean, 43 million years old.

Picture Credit: Frontiers Press

Lead author of the paper, Dr Magnus Ivarsson explained:

“We propose a “volcanic microfossil atlas” to help select target sites for missions seeking evidence of extraterrestrial life, such as the NASA Mars mission 2020 and ExoMars.  The atlas could also help us to recognise what Mars microfossils might look like, by identifying biosignatures associated with different types of fossilised microbes.”

Life Buried in Deep Rock and Deep Geological Time

Dr Ivarsson and his colleagues study life buried in deep rock and deep geological time.  Looking for the fossilised remains of ancient microbes, that have lived up to one thousand metres below the deepest ocean floors and may have originated more than 3.5 billion years ago.

The Martian Surface But Could the Subsurface Harbour Evidence of Ancient Life?

The surface of Mars.

Evidence of ancient life could be preserved beneath the surface of Mars.

Picture Credit: Frontiers Press

Dr Ivarsson added:

“The majority of the microorganisms on Earth are believed to exist in the deep biosphere of the ocean and continental crust.  Yet we are just now beginning to explore, through deep drilling projects, this hidden biosphere.”

In a saline, water world of extreme pressure, that is in perpetual darkness, fungi, bacteria and other microbes have adapted to feed on the igneous rock that surrounds them.  There are even predator/prey relationships.  These organisms spread through microscopic fractures and cavities forming complex ecosystems.  When these lifeforms die, they can become microfossils, providing a history of their existence.

Fossilised Fungal Mycelia

Fossilised fungal mycelia in a subseafloor basalt.

An image by optical microscopy of an open vesicle in subseafloor basalt from Koko Seamount.  Fossilised fungal mycelia protrude from the vesicle wall, yellow and brownish microstromatolites grow on the hyphae and large calcite crystal occur in the middle of the vesicle.

Picture Credit: Frontiers Press

An Atlas of Microfossils from Igneous Rocks

Scientists are aware that the rocky planets Mars and Earth are very similar geochemically, so by looking at igneous rocks on Earth, this should help guide the search for life on Mars.

Ivarsson explained:

“Our aim is to be able to use the oceanic crust microfossil record as a model system to guide Martian exploration.  Our review of existing knowledge is an important first step, but a more comprehensive understanding of the deep life is needed to show where and what to search for.”

The microfossil atlas would also help to determine which samples should be targeted for return to Earth for further analysis, given the limited payload of the Mars missions.  Perhaps, within two years of this article having been written, we will know the answer to the question about whether or not we are alone in this universe, that there was once, perhaps there still is, microbial life deep underground on Mars.

Could Evidence of  Ancient Life on Mars be Discovered within the Next Two Years?

Synchrotron-based X-ray tomography - an image of fungi and prokaryotic cell-like structures.

Three-dimensional reconstruction made by synchrotron-based X-ray tomography (srxtm).  Fungal mycelium with microstromatolitic structures and remains of prokaryotic cell-like structures in between the fungal hyphae.

Picture Credit: Frontiers Press

The scientific paper can be found here: NASA May Have to Look in Igneous Rocks to Detect Ancient Life on Mars

8 05, 2019

A New Jurassic Scansoriopterygid Dinosaur – Ambopteryx

By | May 8th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Ambopteryx longibrachium – A New Bat-winged Dinosaur

Scientists from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), have identified a new species of flying dinosaur from Jurassic-aged strata in north-eastern China.  This dinosaur has been identified as a member of the Scansoriopterygidae dinosaur family and it had bat-like, membranous wings just like the related Yi qi, that was named and described back in 2015.  The little dinosaur, not much bigger than a starling, had a flap of skin from its arms to its torso, in essence a wing.  It has been named Ambopteryx longibrachium and this discovery supports the idea that within the forests of northern China during the Middle to the Late Jurassic, dinosaurs were experimenting with several different methods of gliding and powered flight.

A Life Reconstruction of the Newly Described Scansoriopterygid Dinosaur Ambopteryx longibrachium

Ambopteryx longibrachium life reconstruction.

A life illustration of Ambopteryx longibrachium.

Picture Credit: IVPP (Chinese Academy of Sciences)

Bizarre and Buck-toothed Little Flying Dinosaur

The fossil specimen was found by a local farmer who supplements his income like many folk in Liaoning Province by searching for fossils in the fine-grained sediments.  It is beautifully preserved and dates to around 163 million years ago, commenting on the discovery, one of the co-authors of the scientific paper, published this week in the journal “Nature”, Jingmai O’Connor of the IVPP stated:

“It would have been this tiny, bizarre-looking, buck-toothed thing like nothing alive today.”

The Beautifully Preserved Fossil Specimen (Ambopteryx longibrachium)

Ambopteryx fossil specimen.

Ambopteryx longibrachium fossil.

Picture Credit: Min Wang IVPP (Chinese Academy of Sciences)

A Secondary Form of Flight That Does Not Involve Feathers

Close to the origins of flight, dinosaurs closely related to birds were experimenting with a range of different wing structures.  One of the most bizarre of these is the scansoriopterygid named Yi qi, (pronounced: Ee-chee), which was described and named in 2015.  This little dinosaur had membranous wings, supported by a curved, rod-like bone (styliform), attached to the wrist.  Soft tissue proximal to the arm bones was interpreted as bat-like wings, although this interpretation was not widely accepted by the scientific community.  However, the discovery of another type of scansoriopterygid dinosaur with the same type of wings demonstrates that members of the Scansoriopterygidae were indeed taking to the air.

The new dinosaur, Ambopteryx longibrachium (meaning “both-wing” and “long arm,” a reference to this second method of dinosaur flight, one that does not involve feathered wings), provides confirmatory evidence of the evolution of dinosaurs with bat-like, membranous wings.

Palaeontologist Steve Brusatte, (University of Edinburgh), when asked to reflect on the significance of this newly published scientific paper commented:

“This fossil seals the deal, there really were bat-winged dinosaurs.”

Ambopteryx longibrachium – Takes to the Air

A gliding Ambopteryx longibrachium (dorsal view).

Ambopteryx longibrachium (dorsal view).  The speculated flying pose of this new Chinese dinosaur.

Picture Credit: Min Wang IVPP (Chinese Academy of Sciences)

An Evolutionary Dead End

The researchers conclude that marked changes in wing design evolved near the split between the Scansoriopterygidae and the avian lineage, the two clades took very different routes to becoming volant.  Furthermore, the scientists determine that the membranous wings supported by elongate forelimbs present in scansoriopterygids such as Yi and Ambopteryx was a short-lived evolutionary experiment and that the feathered, winged dinosaurs ultimately proved to be the more successful leading to the eventual evolution of the Aves.  The likes of Yi qi and Ambopteryx longibrachium were evolutionary dead ends.  Whether Ambopteryx was capable of sustained powered flight, or whether it moved from tree to tree entirely by passive gliding remains unknown.

Coming in to Land – Ambopteryx longibrachium

At home amongst the trees Ambopteryx longibrachium.

Coming into land, a gliding Ambopteryx moving effortlessly from tree to tree.

Video Image Credit: Min Wang IVPP (Chinese Academy of Sciences)

Stomach Contents Preserved

The stomach contents of the little dinosaur have been preserved.  The Chinese scientists recovered pieces of bone and small stones (gastroliths), which modern birds use to grind plant material, indicating Ambopteryx may have been omnivorous.  It may have lacked pinnate feathers, but the body was covered by a downy fuzz to help this small dinosaur keep warm.  Jingmai O’Connor speculates that male Ambopteryx may have sported long, ornamental tail feathers, as seen in other scansoriopterygids such as Epidexipteryx (E. hui).

The scientific paper examines the anatomical traits that enabled a mode of flight.  The wings of Ambopteryx were formed by elongated arm bones (humerus and ulna).  Aves (birds), have elongated finger bones (metacarpals), in effect, different solutions found in nature to achieve the same aim – volant activity.

Professor O’Connor added:

“The main lift-generating surface of bird’s wings is formed by the feathers.  In bats, pterosaurs and now scansoriopterygids, you have instead flaps of skin that are stretched out in between skeletal elements.”

Yi qi was Not Alone

It seems likely therefore, that with the discovery of a second bat-winged scansoriopterygid, there may be numerous other fossils of bizarre dinosaurs that were adapted to a life in the trees awaiting discovery in Liaoning Province.  It now seems that flight evolved more than once in the Dinosauria, Yi qi was not alone and the scientific community will provide further insight in the near future with regards to the remarkable and arguably the strangest of all the dinosaurs the Scansoriopterygidae.  Such research might be hindered by the small body-size of these creatures, the Ambopteryx specimen represents a sub-adult animal, it would have measured in life around 32 cm in length and weighed just a few hundred grammes.  Epidexipteryx and Yi qi were also small, E. hui has been estimated to have measured 30 cm long and weighed less than 200 grammes, whilst Yi qi is estimated to have had a wingspan of less than 60 cm and it would have been not much heavier.  The fact that any specimens of these tiny arboreal dinosaurs have survived at all is remarkable in itself.

A spokesperson from Everything Dinosaur commented:

“Much of our knowledge about these tree-dwelling dinosaurs has been derived from fossils discovered in the last twelve years or so.  Our blog was started back in 2007 and over the course of the life of our blog we have charted the rise in the knowledge and awareness surrounding the curious Scansoriopterygidae.  There has even been a model of scansoriopterygid produced by a mainstream manufacturer.  PNSO introduced a model of Yi qi this year.  Who knows what other remarkable dinosaurs are awaiting discovery?”

The PNSO Yi qi Dinosaur Model

Yi qi dinosaur model (PNSO).

PNSO Yi qi dinosaur model.

Picture Credit: Everything Dinosaur

To read about the discovery of Epidexipteryx: Is it a Bird? Is it a Plane? No, it’s Epidexipteryx!

To read about the discovery of Yi qiYi qi The Dinosaur that Thought it was a Bat

To view the Yi qi dinosaur model and the other figures in the PNSO model range: PNSO Age of Dinosaurs

6 05, 2019

Suskityrannus – Our Best Glimpse Yet of a Mid-Cretaceous Tyrannosauroid

By | May 6th, 2019|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Suskityrannus hazelae – The Shape of Things To Come

The first of what will probably turn out to be numerous new Theropod dinosaurs from southern Laramidia has been announced today.  Writing in the academic journal “Nature: Ecology & Evolution”, a team of international scientists have described a new species of relatively small-bodied tyrannosauroid that helps to fill a gap in the evolution of the Tyrannosaur family.  Significantly, the new dinosaur, named Suskityrannus hazelae, has the same general body shape and feet adapted to running (arctometatarsalian feet), as the later, much larger Tyrannosaurs such as Albertosaurus, Gorgosaurus and T. rex.  This suggests that Tyrannosaurs evolved many of their characteristic features whilst they were relatively small, secondary predators.   When Suskityrannus roamed western North America some 92 million years ago (Middle Turonian faunal stage), this little Theropod was the shape of things to come.

A Life Reconstruction of Suskityrannus hazelae

Suskityrannus hazelae life reconstruction.

The newly described Suskityrannus walks past two unconcerned Zuniceratops.

Picture Credit: Andrey Atuchin

The Moreno Hill Dinosaur Assemblage

Suskityrannus heralds from the Zuni Basin of New Mexico, specifically the Moreno Hill Formation and it has been described based on two associated but fragmentary skeletons.  Even so, these fossils represent the most complete examples of early Late Cretaceous tryannosauroids described to date.  Dinosaur fossils from the Turonian faunal stage are exceptionally rare, the fossils from the Moreno Hill Formation have provided palaeontologists with an insight into the types of dinosaur that were the forerunners of the key groups of dinosaur that were to dominate the terrestrial ecosystems of North America towards the end of the Cretaceous.  For example, the beautiful life reconstruction of Suskityrannus by Andrey Atuchin (above),  shows a three-metre long Theropod about to feed on some garfish that have become stranded as a result of a flood.  The pair of Zuniceratops are unconcerned about the proximity of the meat-eater, they are many times heavier and have nothing to fear from the fleet-footed tyrannosauroid.  In the background, to the right of the image a large Ornithopod dinosaur can be seen, we think this is probably a life reconstruction of the basal hadrosauroid Jeyawati.

In essence, that is what makes the dinosaurs from the Moreno Hill Formation so significant.  These sediments were laid down before the diversification of the tyrannosaurids, hardrosaurids and ceratopsids, all key components in later Cretaceous dinosaur assemblages from North America.

A Powerful Bite

Named Suskityrannus hazelae, (pronounced Sus-key-tie-ran-us haze-ah-lie), analysis of the jaw bone indicates that this dinosaur had an elongated skull measuring between 25 and 32 cm in length.  Despite its small size, less than 3 metres long, with a hip height of around 1 metre, Suskityrannus had a powerful bite, foretelling the evolutionary direction of later Tyrannosaurs which were to evolve massive skulls with bone crushing bite forces.

The Fossil Skeleton of S. hazelae Compared to the Dentary (Lower Jaw) of Tyrannosaurus rex

Suskityrannus compared to the jaw bone of a T. rex.

The fossil remains of Suskityrannus compared to a lower jaw from a Tyrannosaurus rex.

Picture Credit: Virginia Tech

What’s in a Name?

The name Suskityrannus hazelae is derived from “Suski,” the Zuni Native American tribe word for “coyote,” reflecting this tyrannosauroid’s position in the ecosystem as a secondary predator.  The species name honours Hazel Wolfe whose support made possible many expeditions to the Zuni Basin of New Mexico.  The first evidence, including a partial skull was found in 1997 by co-author Robert Denton (GeoConcepts Engineering).  The second, more complete specimen was found in 1998 by Sterling Nesbitt, a high school student at the time, but now based at the Department of GeoSciences (Virginia Tech).  Dr Nesbitt is the corresponding author for the scientific paper.  The fossils were housed at the Arizona Museum of Natural History for many years before they were formally studied.

Co-author, Steve Brusatte (School of GeoSciences, University of Edinburgh) commented:

“Suskityrannus is a key link between the enormous bone-crunching dinosaurs like T. rex and the smaller species they evolved from.  The new species shows that Tyrannosaurs developed many of their signature features like a muscular skull, broad mouth, and a shock-absorbing foot when they were still small, maybe as adaptations for living in the shadows.”

Dr Sterling Nesbitt and Suskityrannus hazelae

Co-author Sterling Nesbitt and fossil remains of Suskityrannus.

Corresponding author Sterling Nesbitt, with the fossilised remains of Suskityrannus laid out in their anatomical position.

Picture Credit: Virginia Tech

The Moreno Hill and the Bissekty Formations

The Moreno Hill Formation is analogous to the Bissekty Formation of Uzbekistan.  Within the northern hemisphere, dinosaur fossils from the Turonian faunal stage are exceptionally rare, although thousands of miles apart, the strata are approximately the same age (around 90 million-years-old) and the dinosaur specimens found provide evidence of similar faunas.  The tyrannosauroid Timurlengia was named and described from fragmentary remains from the Bissekty Formation in 2016, the publication of a scientific paper on Suskityrannus will help palaeontologists to better understand how relatively small-bodied tyrannosauroids evolved into giant apex predators some twenty million years later.

To read about the discover of Timurlengia: Fossil Study Suggests How Tyrannosaurs Got Big

How Big Were the Arms of Suskityrannus?

As for that other famous Late Cretaceous Tyrannosaur body trait, the much reduced arms, scientists are very much in the dark about how big the forelimbs of Suskityrannus were.  Very little forelimb fossil material has been recovered.  Scientists can’t even say with any certainty whether Suskityrannus had two-fingered or three-fingered hands.  Cross-sectional analysis of slices of bone indicate that both known specimens were juveniles.  The fossils are providing further information on tyrannosauroid ontogeny.  Despite not being fully-grown, the authors are confident that Suskityrannus was not as big as its descendants, the famous apex predators of the Campanian and Maastrichtian faunal stages of the Cretaceous.

Commenting on the discovery a spokesperson from Everything Dinosaur stated:

“When we made our palaeontology predictions for 2019, the last prediction we made was that more tyrannosaurids would be named and described from fossil material associated with southern Laramidia.  We suggested that two new species would be named.   Suskityrannus hazelae has helped us to confirm our prediction made earlier this year, at least in part.  We are expecting more Theropod news to come out of the southern United States over the next few months.  These are exciting times for anyone studying the Tyrannosauroidea.”

To read about the discovery of a tyrannosauroid from central Utah that lived approximately four million years before Suskityrannus: Moros intrepidus Fleet Footed Tyrannosauroid Leaps 70 Million Year Gap

1 05, 2019

Denisovans Lived on the “Roof of the World”

By | May 1st, 2019|Dinosaur and Prehistoric Animal News Stories, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Jaw Fossil Indicates Denisovans Occupied the Tibetan Plateau

Denisovans, occupied the Tibetan Plateau long before Homo sapiens arrived in the region.  Furthermore, the ability to cope with less oxygen at high altitudes may have been passed onto our species when ancient members of Homo sapiens, bred with Denisovans.  The analysis of a fragmentary lower jaw bone reveals the presence of Denisovans at least 160,000 years ago at the Baishiya Karst Cave complex in Xiahe, China.  The ability to survive in such extreme climates had been thought to be a unique trait of H. sapiens, that is now not the case and what is more, the enigmatic and poorly known Denisovans seem to have passed on a gene that helps modern people cope with living at high elevations.

A Digital Reconstruction of the Fossil Mandible

A digital reconstruction of the Xiahe mandible identified as Denisovan.

View of the virtual reconstruction of the Xiahe mandible after digital removal of the adhering carbonate crust.  The mandible is so well preserved that it allows for a virtual reconstruction of the two sides of the mandible.  Mirrored parts are in grey.

Picture Credit: Jean-Jacques Hublin (MPI-EVA)

The study, undertaken by a team of international researchers including Shara Bailey (New York University), as well as scientists from the Institute of Tibetan Plateau Research, the Chinese Academy of Sciences, Lanzhou University, and the Max Planck Institute for Evolutionary Anthropology, has been published in the journal “Nature”.

Using a technique known as ancient protein analysis, the researchers found that the mandible’s (lower jaw) owner belonged to a Denisovan population from Siberia.  This population occupied the Tibetan Plateau, regarded as the “Roof of the World” because it rises three miles (five kilometres), above sea level.  This suggests that the enigmatic Denisovans were adapted to a low oxygen environment.  In contrast, evidence of Neanderthals is rarely found above 2,000 metres and what evidence there is, probably indicates that Homo neanderthalensis populations only occasionally climbed to such heights, perhaps for the purpose of a special hunt or ceremony.  They do not seem to have persisted at high altitude.

The research team state that Denisovans had already adapted to living in this high-altitude setting significantly prior to the appearance of Homo sapiens.  Previous genetic studies found present-day Himalayan populations carry the EPAS1 allele in their genome, passed on to them by Denisovans, which helps with adaptation to their specific and demanding environment.

A Posterior View of the Fossil Mandible

Digital reconstruction of the Denisovan jaw bone from China.

Digital reconstruction of the Denisovan jaw bone.  Reconstructed area is shaded grey.

Picture Credit: Jean-Jacques Hublin (MPI-EVA)

Who were the Denisovans?

Denisovans are members of a hominin group currently only known directly from fragmentary fossils, the genomes of which have been studied from a single site, Denisova Cave in Siberia.  They are also known indirectly from their genetic legacy through gene flow into several low-altitude East Asian populations and high-altitude modern Tibetans.  The presence of a new species of ancient human was confirmed when a research team led by Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology (MPI-EVA), conducted a genetic study on a single fossil finger bone from the Denisova Cave site.

To read an article from 2010 that summarises the Max Planck Institute for Evolutionary Anthropology research: Finger Bone Hints at New Species of Hominin.

Commenting on the significance of linking a fossil to the Tibetan Plateau, one of the paper’s co-authors Jean-Jacques Hublin (MPI-EVA), stated:

“Traces of Denisovan DNA are found in present-day Asian, Australian, and Melanesian populations, suggesting that these ancient hominins may have once been widespread.  Yet, so far, the only fossils representing this ancient hominin group were identified at the Denisova Cave.”

Indeed, Everything Dinosaur published a report back in 2016 that linked the Inuit people of the Arctic to a Denisovan ancestry: Extinct Human Cousin Helped the Inuit Survive.

A Photograph of the Actual Fossil Jaw Bone (Lateral View)

Denisovan fossil jaw bone ( Baishiya Karst Cave).

Xiahe Denisovan jaw bone from the Baishiya Karst Cave (Gansu Province, China).

Picture Credit: Dongju Zhang (Lanzhou University)

Discovered by a Monk

In this newly published paper, the researchers describe a hominin lower mandible that was found on the Tibetan Plateau in the Baishiya Karst Cave in Xiahe, Gansu Province, China.  The fossil was originally discovered in 1980 by a local monk who donated it to the 6th Gung-Thang Living Buddha who then passed it on to Lanzhou University.  Since 2010, researchers Fahu Chen and Dongju Zhang from Lanzhou University have been studying the cave site from where the mandible originated in a bid to find more human remains.  In 2016, a collaboration began with the Department of Human Evolution at the Max Planck Institute for Evolutionary Anthropology and although no DNA has been recovered, the team did manage to extract proteins from one of the large molars within the jaw.  These proteins were then categorised using a technique called ancient protein analysis.

The Reconstructed Denisovan Jaw Bone

Denisovan jaw bone identified on the Tibetan Plateau (digital reconstruction).

A view of the Denisovan jaw bone from China. The grey area represents reconstructed elements.

Picture Credit: Jean-Jacques Hublin (MPI-EVA)

Piecing Together the Face of a Denisovan

The fossil record of the Denisovans is particularly sparse, it is limited to just some teeth and part of a finger.  This is the first fossil of its kind to be found and perhaps, if more Denisovan fossils can be discovered, then it hints at the possibility that anthropologists might be able to reconstruct the skull.

Co-author Shara Bailey explained:

“Although we still do not know the shape and size of the Denisovan skull, now with a lower jaw we can start to piece together the puzzle of what they actually looked like”.

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

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