Scientists Attach Prosthetic Dinosaur Tails to Chickens

Why did the chicken with the prosthetic tail cross the road?  So that scientists can simulate the walking motion of Theropod dinosaurs in a bid to learn more about the way in which dinosaurs moved around.  That’s the rather bizarre summation from a study into non-avian, bipedal dinosaur posture and locomotion carried out by researchers at the University of Chile, working in collaboration with colleagues from the University of Chicago.

Ancestral Traits

Aves (birds) still share a number of ancestral traits of the Dinosauria and as such they can be utilised as experimental subjects to assess certain aspects of dinosaur anatomy and even inferred behaviour.  In this particular study, chickens were fitted with prosthetic tails as they grew so that scientists could assess how Theropod dinosaurs walked in comparison with their very much shorter-tailed descendants.  As birds evolved during the Mesozoic, so a number of forms gradually lost their long, reptilian tails, a tail is prominent in the fossils of Archaeopteryx (A. lithographica).  Indeed, one of the ways to tell birds apart from Maniraptoran dinosaurs in the fossil record is to count the number of likely caudal vertebrae (tail bones).

Prosthetic Dinosaur Tails

As a simple rule of thumb, if more than twenty-five tail bones are associated with the skeletal material, then chances are, you are looking at the fossilised remains of a dinosaur.  Less than twenty-five tail bones and the identification starts to lean more towards the Aves (birds).  Birds lost most of their tail as they evolved into more and more efficient fliers.  The long tail of Archaeopteryx would have made it quite a clumsy aeronaut.  Later birds, more competent fliers than Archaeopteryx for example, lost most of their tail.

Modern birds have a pygostyle, a vestigial tail that is composed of their last five caudal vertebrae fused into a plate of bone, the evolution of birds shows trends towards a lightening of the skeleton such as the loss of teeth and the gradual reduction in tail length.

The Locomotion of Theropod Dinosaurs

This then gives scientists a bit of puzzle when it comes to using birds to mimic the locomotion of theropod dinosaurs, birds don’t have a long tail and the addition of a tail alters the centre of gravity in relation to the rest of the body mass and effects the way a creature can move about.  The solution is simple, add artificial tails to your subject chickens as they grow.  With the tail the birds have to modify their gait and motion and therefore scientists can learn more about the movements of those long-tailed dinosaurs.

Extant birds today, maintain a crouched hind-limb posture and their locomotion is powered by knee flexion.  In non-avian Theropods, by contrast, scientists speculate that these dinosaurs had a more upright posture and limb movement powered by femur (thigh bone) retraction.  To test this theory, young chicks had a series of artificial tails attached to them from two days of age.  As the hatchlings grew, so bigger tails were fitted to mimic the growth of the tail in a young dinosaur.

Calculating Tail Weight

The scientists worked around a tail weight roughly equivalent to 15% of the bird’s total body mass, roughly the proportional weight of a theropod dinosaur’s tail when compared to the weight of the entire dinosaur’s body.  Velcro straps were used to keep the wooden, prosthetic tails in place and the scientists noted that by manipulating the location of the centre of mass within the chickens, the birds began to alter their locomotion and posture to accommodate the tail.

The Addition of a Tail Alters the Way In Which Chickens Walk

Watch the birdie!

Picture credit: PLoS One

Artificial Dinosaur Tails

Artificial tails provide clues to non-avian dinosaur locomotion.  In the diagram (A), above, those birds used as controls have their hind-limbs shaded grey, those chickens with a counter weight added anteriorly (hind-limbs shaded yellow) and those chickens with tails (orange hind-limbs).  Estimations of the centre of mass of the tail rig (tCOM), as well as of a control (cCOM) and of an experimental individual (eCOM), are shown.   With the tail added, the centre of mass is moved towards the rear of the bird.  (B) Diagram showing the segmental angles (f, femur; tt, tibio-tarsus; tm, tarso-metatarsus) and joint angles (k, knee; a, ankle) used in this study.

It was noted that the chickens began to recreate the limb posture and kinetic movements inferred for bipedal dinosaurs.  The more rearward located centre of gravity indicated a more vertical orientation of the thigh during standing and increased femoral displacement during walking.

Commenting on the research, lead author of this rather unusual study, Bruno Gossi (Institute of Ecology and Biodiversity, University of Chile) wrote:

“We attached more realistic artificial tails to chickens shortly after hatching and allowing proper exercise, we expected adult chickens with added tails to show a more vertical femur in standing position and increased femoral excursion during locomotion.”

Changing the Centre of Body Mass

The research team states that this study supports the hypothesis that gradual changes in the position of the centre of body mass (posterior located with tail, to anterior located without a tail), resulted in a more crouched hind-limb posture and a shift form hip-driven limb movements to the knee-driven limb movement seen in extant birds.

Having mastered  the technique of adding artificial tails to chickens thanks to Velcro, the scientists are confident that this type of research can be used to gain further, significant insights into previously unexplored aspects of bipedal theropod locomotion.

Last spring (April 2013), Everything Dinosaur reported on some research into the posture of birds carried out by scientists including a team from the Royal Veterinary College which looked at the relationship between the Aves and the Dinosauria in terms of derived posture.  So in answer to the question how did dinosaurs walk? Get yourself a chicken.

To read more about this article: Birds Have the Dinosaurs to Thank for Their Crouching Gait.

Out thanks to Constantine, for reminding us to post something up about this research.

For replicas of theropod dinosaurs and other prehistoric animals: CollectA Deluxe Prehistoric World Models.

Serrated Teeth – The Secret of Dimetrodon’s Success

Long before the first dinosaurs evolved, one of the top terrestrial predators on the planet was Dimetrodon, the famous sail-backed reptile, a pelycosaur and now a new study by University of Toronto scientists suggests how this large carnivore was able to achieve apex predator status.

Dimetrodon

Graduate student Kirstin Brink, in collaboration with Professor Robert Reisz (University of Toronto), have studied the dentition (teeth) of a number of Dimetrodon species and they have discovered that these kinds of mammal-like-reptile were the first land living vertebrates to evolve ziphodont (serrated) teeth.  The pointed, recurved and serrated teeth allowed Dimetrodon to tackle prey animals much larger than itself.  The strong, reinforced skull and these knife-like teeth gave these reptiles a formidable bite, one that was capable of ripping and tearing flesh from their victim’s bodies.

An Illustration of Dimetrodon

Sail-back reptile with ferocious teeth.

Picture credit: Safari Ltd/Everything Dinosaur

To view models and replicas of Palaeozoic animals: Wild Safari Dinos and Prehistoric World Models.

Sail-backed Reptile

Dimetrodon is one of the easiest to recognise of all the prehistoric animals, thanks to its huge “sail” that rose up out of this animal’s back.  This is a feature found in a number of pelycosaurs, although palaeontologists remain uncertain as to its exact role and function.   Models of this Permian predator are often found in “dinosaur model sets” although the Dimetrodon genus was extinct millions of years before the first dinosaurs evolved.  A synapsid reptile, Dimetrodon is actually more closely related to mammals than it is to the Dinosauria.

To read an article that attempts to explain why Dimetrodon is often regarded as a dinosaur: Dimetrodon – Often Mistaken for a Dinosaur.

Ziphodont Teeth

Although, most meat-eating theropod dinosaurs had ziphodont (serrated) teeth, this new study suggests that Dimetrodon spp. evolved dentition that was serrated over thirty-five million years before the first dinosaurs.  The scientists used scanning electron microscopy to examine minute structures in the teeth of a Dimetrodon species, analysing specimens from the collection of the Royal Ontario Museum.

Several different species of Dimetrodon were included in the tooth study, the fossils spanning some twenty-five million years of the Permian geological period.

Dimetrodon Species

The scientists conclude that Dimetrodon spp. had a diversity of previously unknown tooth morphology including cusps (raised points on the crowns of the teeth), the dominant morphology of teeth in modern Mammalia. Intriguingly, the researchers suggest that as Dimetrodon spp. evolved into the likes of the giant Dimetrodon grandis, so serrated teeth evolved too.

Ziphodont tooth structures are absent in earlier species of the Dimetrodon genus.  As the skull morphology remains relatively consistent across all the Dimetrodon species studied, it is the shape of the teeth that change, this indicates a gradual change in feeding habits.

The Teeth of D. grandis Show “Tell-Tale” Serrations

Study maps evolution of serrated teeth in Dimetrodon species.

Picture credit: University of Toronto

The picture shows a Dimetrodon grandis tooth specimen from the Royal Ontario Museum (Canada) (a), along with various scanning electron microscope images showing the serrations (b-e).

Professor Reisz explained:

“This research is an important step in reconstructing the structure of ancient, complex communities.  Teeth tell us a lot more about the ecology of animals than just looking at the skeleton.”

A spokesperson from Everything Dinosaur commented:

“It is very likely that Dimetrodon species such as D. grandis were highly mobile, apex predators, this new study provides further insights into how these large reptiles came to dominate terrestrial environments of the Late Permian.”

Research into Dentition

The research into the dentition of Dimetrodon and the way in which the teeth evolved but the skull shape and structure remained relatively unchanged suggests a change in feeding style and trophic interactions.  The term trophic, when used in biology, refers to feeding styles and nutrition.  The researchers conclude that ziphodont teeth evolved in the larger species of Dimetrodon independently from the ziphodont teeth that has been recorded from later therapsids.

The likes of Dimetrodon grandis would certainly have been one animal best avoided during the Permian, Professor Reisz stated:

“The steak-knife configuration of these teeth and the architecture of the skull suggest Dimetrodon was able to grab and rip and dismember large prey.  Teeth fossils have attracted a lot of attention in dinosaurs but much less is known about the animals that lived during this first chapter in terrestrial evolution.”

Dinosaur Bones Found in College Grounds

For school pupils at Ardingly College, an independent, fee paying school located in West Sussex, local history lessons just got a little more interesting with the discovery of a large number of fossils dating back to the Early Cretaceous.  The fossils described as a “treasure trove” by some observers include several dinosaur bones, the remains of crocodiles, freshwater turtles, fish scales, plants and a number of invertebrates including bivalves.

Dinosaur Bones

The first discoveries were made back in June as staff and pupils explored rubble and debris excavated as part of building work for a new boarding house.  One of the teachers at the private school took pupils on a “geo-trail” and apparently when studying rocks that had been dug up as part of the construction work, they came face to face with evidence of an Early Cretaceous ecosystem.

For models and replicas of Early Cretaceous dinosaurs and other prehistoric animals: CollectA Deluxe Prehistoric Life Models.

Ardingly College is an independent co-educational boarding and day school for boys and girls aged from under 3 years up to 18 years of age.  It is situated just a few miles away from the West Sussex village of Cuckfield, a location well-known for its Iguanodontid fossil remains.  For dedicated palaeontologists hoping to get a glimpse of these fossils, the College is planning an open day “dig for dinosaurs” event for locals to participate in.

The Ardingly Sandstone Member

This part of West Sussex from a geological perspective, is strongly associated with the Ardingly Sandstone Member which outcrops across the Weald in West Sussex and elsewhere in south-east England.  Fossils deposited in this strata have been dated to the Valanginian faunal stage of the Early Cretaceous (approximately 140 million to around 135 million years ago).  During this part of the Cretaceous the area of land that we now know as the bedrock of West Sussex was formed in a riverine/estuarine environment.

The land was relatively flat and criss-crossed by many slow moving rivers which were making their way down to the shrinking Tethys Ocean, either entering the sea via large bays to the north of West Sussex, land that was to become East Anglia or further to the south, land that is now part of France.

Early Cretaceous Environment

The Ardingly sandstones were deposited across a wide area of these braided river channels and in amongst the sandstones were the remains of animals and vegetation washed downstream.  At the same time, other areas were receiving deposits of much finer grained silts and mudstones, as a result of material being washed into much quieter bays and lagoons.

A team of scientists from the Natural History Museum and Imperial College (London) are currently assessing the fossil material and supervising the mapping of the site.

An Embryonic Atlantic Ocean

A spokesperson from Everything Dinosaur commented:

“During the Early Cretaceous, the embryonic Atlantic Ocean was beginning to divide up the landmasses of Eurasia, Africa and the Americas and the terrestrial fauna was dominated by the Dinosauria.  Due to the amount of urban development in this part of the world today, it is rare for this amount of fossiliferous strata to be exposed and hopefully this location will add to our knowledge regarding the environment and the animals and plants that lived within it during the Early Cretaceous, an important time in Earth’s history in terms of the diversity and radiation of vertebrates such as pterosaurs and dinosaurs.”

This is not the first time fossils have been found in school grounds (nor will it be the last), however back in 2010, team members from Everything Dinosaur reported on the discovery of ichthyosaur fossilised bones (a marine reptile), in a school’s vegetable patch (Richmond State School in western Queensland, Australia).

To read more about this discovery: Marine Reptile Fossils Amongst the Vegetables.

“Prehistoric Pompeii” Led to Preservation of Early Cretaceous Liaoning Ecosystem

The fine grained, siltstones associated with the quarries near Sihetun in the northern Chinese province of Liaoning have become famous over the last twenty years or so, as it is from these quarries that some of the most exquisitely preserved vertebrate fossils that have ever been found have come.  Several kinds of feathered non-avian dinosaurs are known, as are numerous primitive birds, lizards, mammals, evidence of flowering plants, insects, other invertebrates and fish.

Pyroclastic Cloud

It is from these Lower Cretaceous deposits that dinosaurs such as Sinosauropteryx, Sinornithosaurus and a species of Psittacosaurus have been discovered.  Such is the wealth of fossil material preserved that scientists have been able to piece together a huge amount of information about the fauna and flora in this part of China that lived around 133 to 120 million years ago.  The ecosystem is known as the Jehol Biota and represents one of the most complete fossil ecosystems recorded from Mesozoic aged strata.

Many of the fossils reveal dinosaurs with bristle-like, proto-feathers and the numerous bird fossils (such as Confuciusornis spp.) even have their stomach contents preserved.  But how did all these animals and plants come to be fossilised in such wonderful preservation and in such quantities?

Exceptional Fossil Preservation

A team of international scientists, including experts from the Chinese Academy of Sciences, Nanjing University (Jiangsu Province, eastern China), in collaboration with colleagues from the American Museum of Natural History (New York) and Los Alamos Laboratory (New Mexico) have proposed that a series of deadly pyroclastic clouds hitting the area may have been responsible for the mass extinction and deposition of the body fossils.

Amazing Early Cretaceous Fossils from Liaoning Province (China)

A genuine fossil of a Cretaceous bird (Yanornis martini).

Preserving Tiny Anatomical Details

Such is the quality of the fossil specimens that even tiny anatomical details have been preserved in the fossil material.  These fossils have helped palaeontologists to piece together important data relating to the phylogenetic relationship of the Dinosauria to Aves (dinosaurs to birds) as well as providing a detailed insight into the evolution of the birds themselves.

To read an article about a recently discovered primitive bird fossil discovered in western Liaoning: Bird Evolution Not as Easy as Eosinopteryx.

Such is the quantity and variety of specimens that scientists have puzzled how such a large assemblage of fossil material, with such excellent preservation, came about.  Previously, it had been thought that the remains of animals, plants and birds and all the other material had been washed into a large, stagnant lake.  The corpses and plant material rapidly sinking to the muddy bottom and becoming quickly buried.

Active Volcanoes

Volcanoes were active in the area during this stage of the Cretaceous and fine ash deposits from volcanic eruptions covered the specimens and aided their preservation.  Now a team of international scientists writing in the academic publication the “Journal of Nature Communications” have proposed that sudden and very localised, periodic  pyroclastic flows from the surrounding volcanoes were responsible for the sweeping of large amounts of organic matter into the lakes and its subsequent exceptional fossil preservation.

Scientists Had Puzzled Over the Exquisite Liaoning Fossil Preservation

An adult Hyphalosaurus and baby turtle died together.

In the picture above a baby turtle has come to rest on top of a Hyphalosaurus (freshwater reptile, whose fossils are common in the Jehol Biota).  Both body fossils are complete and immaculately preserved.  There are many such examples of amazing fossil preservation and the researchers postulate that phreatomagmatic eruptions (volcanic eruptions caused by (most likely) rapid cooling of magma in contact with a body of water) forced pyroclastic flows to rapidly cover the surrounding countryside.

A Pyroclastic Flow

A pyroclastic flow is a cloud of hot gas and ash that tumbles away from a volcanic explosion at huge speed.  The hot gases, sometimes approaching 1,000 degrees Celsius, instantly kills everything in its path.  The Roman city of Pompeii was hit by such a pyroclastic flow.  Scientists have termed the forces responsible for the Liaoning preservation as “prehistoric Pompeiis”.

The research team examined and analysed sediments and residual fossils from several key horizons in the Lower Cretaceous Jiufotang and Yixian formations in a bid to understand more about the nature of the events and the mechanisms behind the exceptional fossil preservation.  The team conclude that the terrestrial material was transported by an sealed within the pyroclastic flows, thus providing palaeontologists with a unique record of the flora and fauna of the forested lowlands of this part of northern China.

Fossils of Both Terrestrial and Freshwater Vertebrates Buried Together

A victim of a pyroclastic flow?

Turtle Fossils

There are many examples of turtle fossils preserved in the Yixian and Jiufotang formations.  These animals have remained little changed for over 130 million years.

Lead researcher and one of the main authors of the scientific paper Baoyu Jiang (Nanjing University), stated:

“All the studied fossils are directly embedded within pyroclastic flows.  And the preserved animals are characterised by entombment poses and showed evidence of charring, similar to those associated with victims at Pompeii.”

The researchers have proposed that the burials were not the result of a single event, but that there were probably several eruptions that occurred, most would have been small, localised but very violent causing localised mass extinctions.

Professor Mike Benton (Bristol University) commented:

“The new observations confirm and clarify what had been suspected.  But the authors go a step further in suggesting that all the Jehol animals were killed, transported and exceptionally preserved by the pyroclastic flows.”  This is quite a challenge to previous views that assumed most of the animals lived in and around the lakes in which they are found, and may have been transported in by regular rivers and other means.”

To view models and replicas of the Jehol Biota and other prehistoric animals: Age of Dinosaur Models from PNSO.

Gobivenator mongoliensis – A New Troodontid from the Central Gobi Desert

A new scientific paper has just been published by an international team of scientists including researchers from Tokyo University that details the discovery of a troodontid dinosaur.  Troodonts are a group of small theropod dinosaurs that seem to lie somewhere between those speedy, long-legged ornithomimids such as Gallimimus and the fearsome dromaeosaurids such as Velociraptor.

New Troodontid Dinosaur

Fossils of these little dinosaurs (most of them were around two metres in length, most of that being tail), have been found in Upper Cretaceous deposits of North America and Asia.  From the several near complete specimens of this family known, palaeontologists have identified that their skeletons were very bird like and that these animals in proportion to the rest of their bodies, had relatively large brains for a member of the Dinosauria.

The newest member of the Troodontidae has been named Gobivenator mongoliensis (the name means “Gobi desert hunter from Mongolia”).  The almost complete specimen, including a very well preserved skull which was just missing the tip of the snout was excavated from deposits in the Djadokhta Formation of the central Gobi desert region.  Post cranial material includes virtually the rest of the skeleton with just some smaller bones and a neck vertebra (cervical vertebrae) missing.  A number of important Late Cretaceous fossils representing oviraptorids, dromaeosaurids, tyrannosaurs, as well as ornithischian dinosaurs, mammals, lizards and crocodiles have been found in the strata that makes up the Djadokhta Formation.

Gobivenator mongoliensis

Perhaps the most famous part of the Formation is the famous “Flaming Cliffs” , named for the reddish colour of the sandstones, as explored by the American Museum of Natural History expeditions led by Dr Roy Chapman Andrews.

The sandstone deposits of the Djadokhta Formation preserve evidence of a semi-arid, desert environment that had a number of oasis spread across it.  The fossils of Gobivenator have been dated to around 72 million years ago, although the exact date range of the entire Formation remains debated.  Most of the strata does date from the Early Maastrichtian/Campanian, but there is some evidence to suggest that the earliest deposits, representing a slightly more humid and wet environment date from the Santonian faunal stage.

Measuring around 1.6 metres in length (half of the body length being made up of the long tail) and most probably feathered, Gobivenator was probably a hunter of small, lizards, baby dinosaurs and mammals.  It may have lived in social packs.

An Illustration of Gobivenator mongoliensis

An illustration of G. mongoliensis.
Scale bar = 1 metre.

Picture credit: Danny Cicchetti

The Newest Member of the Troodontidae

The near complete skeleton and the very well preserved and undistorted skull has provided the joint Japanese/Mongolian scientists with a unique opportunity to explore the phylogenetic relationship between members of the Troodontidae and also between troodonts and Aves (birds).  The shape and structure of the palate has been determined, showing close affinities with dromaeosaurids such as Velociraptor and primitive birds.

For articulated models of troodontids and dromaeosaurids: Beasts of the Mesozoic Articulated Dinosaur Figures.

Although the skull of Gobivenator is strongly fused (akinetic – limited movement between bones), it already shows preconditions for the later evolution of a more flexible skull as seen in many types of modern bird (cranial kinesis).  Preconditions identified by the research team include reduced contact between the small bones that make up the palate and the absence of a slender epipterygoid bone.

Cranial kinesis is effectively the ability of skull bones to flex against each other.  This adaptation is most closely allied to the need to cope with awkward or difficult to swallow prey items.  A number of bird families show a degree of cranial kinesis, most notably Prokinesis (flexing of the front facing portions of the skull).  In modern Aves, it is the psittacine (parrots) family that show the most pronounced form of cranial kinesis.  It is thought that the skull flexing in members of the parrot family evolved to help them feed on large, robust nuts and fruit.

The scientific paper detailing this research has been published in the academic journal “Naturwissenschaften” – the science of nature.

University of Alberta to Display Important Dinosaur Discoveries

The almost complete fossilised skeleton of a baby horned dinosaur and the preserved skull from an adult duck-billed dinosaur that shows evidence of a soft crest on top of its head are to go on display to the public in the Canadian city of Edmonton.  From February 6th until March 8th, visitors to the University of Alberta Museum’s galleries at Enterprise square will be able to view the fossilised remains of a baby Chasmosaurus along with the rooster-like comb on the skull of an Edmontosaurus (E. regalis).   These dinosaur fossils were amongst the most significant discoveries reported upon by Everything Dinosaur team members last year.

Dinosaur Provincial Park Formation

It is rare to find a baby dinosaur, these carcases decompose more rapidly than larger adult specimens and most baby dinosaur remains would have been snapped up by a passing meat-eater.  To have an almost perfectly preserved example of a young horned dinosaur is a great boost for the palaeontologists working in the Dinosaur Provincial Park Formation.

The Chasmosaurus skeleton is nearly complete, only the front limbs are missing, which are believed to have disappeared down a sink hole in the past.  The dinosaur has been affectionately called “baby” and if visitors look carefully, they will be able to make out 72 million year old preserved skin impressions on the specimen over the ribs of the 1.5 metre long specimen.

Phil Currie (Canada Research Chair in Dinosaur Palaeobiology at the University of Alberta) Shows Off the Fossil Find

“The best preserved baby horned dinosaur ever found”.

Picture credit: Bruce Edwards (from a video interview)

To read more about the baby Chasmosaurus fossil: Baby Chasmosaurus Fossil Unearthed in Alberta.

University of Alberta

Clearly excited about the prospect of putting this fossil, which was discovered in 2010, on public display, Phil Currie stated:

“It’s my pride and joy.  It is the best preserved baby horned dinosaur known anywhere in the world.  It is an unbelievable specimen!”

Joining “baby” on display will be skull material from an adult duck-billed dinosaur (Saurolophinae), called Edmontosaurus.  This specimen, Edmontosaurus regalis revealed for the first time evidence that these large, herbivores may have had soft-tissue crests on their heads, rather like the combs on cockerels.

Everything Dinosaur reported on this discovery, when the scientific paper was published in “Current Biology” just five weeks ago.  To read more about this study: Dinosaur with a Comb Like a Rooster’s.

The Edmontosaurus Material Going on Display

Arrows indicate preserved impression of skin, the presence of a crest and skull bones.

Picture credit: Frederico Fanti et al/Current Biology

A spokesperson from Everything Dinosaur commented:

“The fact that these recently described specimens are going on display to the public so quickly is fantastic news.   We applaud the staff at the University of Alberta for all their hard work.  These two fossil discoveries are very significant and they demonstrate to the public at large that we still have so much to learn about the Dinosauria.”

Trace Fossils Including Pterosaur Trackways Discovered in Rajasthan

The north-western province of Rajasthan in India has some spectacular limestone formations that represent sediments laid down in the Middle Jurassic.  A number of expeditions have been mounted to this part of India by institutions such as the University of Rajasthan to help map the geology and assess the many different types of marine invertebrate fossils that are associated with some parts of this strata.

Jurassic India

The specimens of ammonites are very useful in helping scientists to accurately date the age of these formations (biostratification) and for comparing the fauna found in these deposits with other sedimentary rock formations found elsewhere on the sub-continent.  Although, the area’s close proximity to the Pakistan border has led to difficulties over accessing some parts of the region, a number of geological surveys have been carried out exploring for reserves of natural gas and oil.  The limestone represent deposition in a marine environment, however, Jurassic sandstones that are also to be found in Rajasthan, most notably in Jaisalmer district, represent material deposited in a fluvial (river) environment.  These outcrops and the fossils contained therein are providing scientists with a fascinating glimpse into life in the Early to Middle Jurassic.

Palaeontologists and geologists visiting this part of India as part of their participation in the ninth annual International Congress on the Jurassic System, organised by the Geology department of Rajasthan University, have been taking the opportunity to explore the area and to look for fossils.  An outcrop of exposed Jurassic aged sediments on the Jodhpur-Jaisalmer highway, close to the village of Thaiat has yielded a number of trace fossils including pterosaur and three-toed dinosaur footprints.

An International Team of Scientists

The thirty-four strong party, including researchers from France and Germany have been staying in this area, with a view to mapping the formations and recording evidence of Jurassic vertebrates.  Little is known about the evolution of the Dinosauria and the Pterosauria (flying reptiles) in this part of the world during the Early Jurassic.

The footprint fossils may potentially belong to species that are new to science.  Dr Jan Schlogl of Slovakia working in collaboration with Professor Gregory Pienkowski (Poland), identified the footprints, preserved in finely grained, sandstone sediments as those belonging to a pterosaur (flying reptile).  Something like over 120 different pterosaur species are now known, mostly via fragmentary fossil remains.  Finding pterosaur tracks in these sediments, believed to date from around 180 million years ago, will help scientists to understand better the evolution and radiation of these vertebrates.

Jurassic Trace Fossils – Trackways

Amongst the footprints representing Jurassic dinosaurs at least two kinds have been identified.  Firstly, there are the small three-toed prints of a little theropod dinosaur known as Grallator.  The name Grallator is an ichnogenus, a name given to a genus of animal that is only known from trace fossils.  Some of the prints, representing the hind feet of this biped are five centimetres in length.  It is likely that this little dinosaur was about the size of a chicken.

Larger three-toed prints have also been identified.  These tridactyl (three-toed) prints measure approximately thirty centimetres long and must have been made by a much larger creature.  It is difficult to speculate what sort of dinosaur made such prints, but similar prints found in European strata of roughly the same geological age have been assigned to Tetanurae theropods such as megalosaurs, whereas, it is possible that these prints could represent another type of theropod such as a member of the Neoceratosauria or a coelophysid.

Rapidly Evolving Theropods

During the Early Jurassic the Theropoda group of meat-eating dinosaurs rapidly evolved and a number of  new families evolved.  If body fossils of meat-eating dinosaurs can be found in these sediments then this would add greatly to our knowledge of theropod dinosaurs from the southern super-continent of Gondwana.

Large Three-Toed Dinosaur Footprints Discovered

Evidence of Jurassic dinosaurs from India.

Picture credit: University of Rajasthan

The larger, tridactyl prints have been assigned to the ichnogenus Eurontes (Eurontes giganteus).

Associate Professor P. K. Pandey (Geology department of the University of Rajasthan), has studied a number of Jurassic aged fossils from these sandstone deposits.  He has already recorded the presence of small pterosaurs after finding fragmentary fossilised bones in these deposits.   A source close to Everything Dinosaur commented that these discoveries of dinosaur footprints and pterosaur footprints were very significant.

For models and replicas of Jurassic theropods and other prehistoric animals: CollectA Deluxe Scale Prehistoric Animal Models.