Category: Dinosaur and Prehistoric Animal News Stories

Deinocheirus – Done and Dusted (For Now At Least)

Solving the Mystery of “Peculiar Terrible Hand”

Back in November 2013, team members at Everything Dinosaur wrote about of the most intriguing reports to come out of the annual Society of Vertebrate Palaeontology meeting that had just come to an end in Los Angeles.  As the dust settled and the researchers made their way home, here was a chance to reflect on the remarkable work done to help finally resolve a fifty year mystery.  What type of dinosaur was Deinocheirus?

Huge fossilised forelimbs and shoulder bones, discovered by a joint Polish/Mongolian expedition to the Gobi desert in 1965 had fascinated scientists for nearly half a century.  The arms were massive, measuring some 2.6 metres in length (including shoulder blades) and each hand ended in three-fingers, each finger tipped with an enormous, curved claw which in one case was over twenty centimetres long.

Based on these huge arms and a few other scraps of fossil bone, most palaeontologists agreed that the fossils represented a giant form of ornithomimid, a member of the “Bird  Mimic” group of Theropod dinosaurs.  Although the arms were much bigger, they did resemble the arms and hands of agile, fast running ornithomimids such as Struthiomimus and Dromiceiomimus.  A formal announcement was made about the discovery in 1966, and Deinocheirus “Terrible Hand” was described based on this holotype material in 1970.

This was the cue for every dinosaur book publisher to include a picture of the fossil material in virtually every dinosaur book produced in the seventies and eighties, although very few attempts to illustrate the dinosaur were actually made if we recall correctly.

The Holotype Fossils of Deinocheirus (Deinocheirus mirificus)

Fearsome arms of Deinocheirus

Fearsome arms of Deinocheirus

Picture Credit: Everything Dinosaur

The woman in the photograph is Professor Zofia Kielan-Jaworowska, the scientist who led the 1965 expedition.  Although the limbs have been repositioned and remounted since this picture was taken, it does provide a very good impression of the scale of those fossilised limbs.

Writing in the journal “Nature” the scientists behind the paper presented at the conference last year have revealed more about the “enigma” that is the Ornithomimosaur Deinocheirus mirificus.  Turns out that this bizarre Theropod is even more amazing than previously imagined.  In the journal, the scientists describe two new specimens of Deinocheirus that were discovered in the same formation (Nemegt Formation) as the original holotype material.  These much more complete fossil remains have enabled the researchers which include Phil Currie (University of Alberta), Yuong-Nam Lee and Hang-Jae Lee (Geological Museum, Korea Institute of Geoscience and Mineral Resources) as well as Pascal Godefroit (Royal Belgian Institute of Natural Sciences), to build up a comprehensive picture of what this dinosaur looked like, where it lived and what it ate.

A New Interpretation of Deinocheirus (D. mirificus)

A bizarre looking Theropod after all.

A bizarre looking Theropod after all.

Picture Credit: Yuong-Nam Lee/Korea Institute of Geoscience and Mineral Resources

It is certainly the largest member of the Ornithomimosauria known to science, with an estimated length of around 11 metres, several tonnes in weight and standing about as tall as a modern-day Giraffe, but it was no vicious super predator.  Studies of the feet and hind legs indicate that this animal was probably a slow walker, one with a huge pot belly to boot.  A pot belly?  This dinosaur had an expanded pelvis with strong muscle attachments.  It probably had a large gut to help it digest the tough plant material that it ate.  The skull measures over a metre in length, but there were no teeth in the deep jaws.  Indeed, over a 1,000 gastroliths have been found in association with the fossils, along with fish remains in the body cavity indicating that this animal was probably a mega-omnivore, eating plants, but also insects, small animals and fish.

Deinocheirus lived next to a large river.  Seventy million years ago, this part of Mongolia resembled the Upper Nile.  The broad, wide toes with their blunt claws were ideally suited to assist this animal when walking over soft mud. It probably wandered into the river to feed on soft water plants, to catch the occasional fish and to avoid the attentions of the Tyrannosaur Tarbosaurus.  However, evidence that Tarbosaurus fed on Deinocheirus has been preserved on some of the bones.  Whether or not the bite marks and feeding gouges that have been identified indicate that Tarbosaurus predated on these large bipeds, or whether these marks were made as a result of scavenging a carcase remains unclear.  However, the deep, “U-shaped” wishbone of this dinosaur and those big shoulder bones suggest that this ponderous giant could inflict some serious damage should any unwary tyrannosaurid venture too close to those huge arms.

This dinosaur had a number of unique skeletal features, it had a pygostyle (fused vertebrae on the end of the tail), like a bird and a much thicker tail than its smaller ornithomimid relatives.  Perhaps one of the most intriguing features are the large number of tall neural spines.  The dorsal and sacral vertebrae have flat, blade-like extensions (neural spines).  To us, these spatulate spines resemble the bones seen in the humps of Bison.  Deinocheirus could have had a sail-like structure on its back, or maybe even a large hump.  It has been suggested that the hump, originally reported upon in 2013, could have been exaggerated. These neural spines could have supported a network of ossified tendons to help support this dinosaur’s huge gut and heavy tail.

An Illustration of Deinocheirus (D. mirificus)

A mega-omnivore that had to watch out for Tarbosaurus.

A mega-omnivore that had to watch out for Tarbosaurus.

Picture Credit: Michael Skrepnick

The model making company Collecta introduced a 1:40 scale replica of the mysterious Deinocheirus back in 2012.  At the time, we commended them for bringing out a model of this dinosaur when so very little of the total skeleton had been studied and described.  With the information regarding the hump, we at Everything Dinosaur amended our scale drawing to give an impression of a small hump over the pelvis, but the latest illustrations really emphasis the hump or sail on this animal’s back.  Ironically, Collecta gave their Deinocheirus model feathers, no evidence of feathers on the original holotype material or indeed on the more recently discovered fossils have been found, but it is thought that a number of ornithomimids were indeed, feathered.

An Illustration of the Collecta Deinocheirus Model (2012)

Scientists speculate that Deinocheirus was covered in simple feathers.

Scientists speculate that Deinocheirus was covered in simple feathers.

As lead author of the scientific paper, Yuong-Nam Lee states the researchers were just as surprised as anyone when they put the complete dinosaur together based on the three main specimens that had been found to date.

Yuong-Nam Lee went on to add:

“The discovery of the original specimen almost half a century ago suggested that this was an unusual dinosaur, but did not prepare us for how distinctive Deinocheirus is.  A true cautionary tale in predicting forms from partial skeletons.”

To view Everything Dinosaur’s origin article on this research, published in November 2013: A Helping Hand for Deinocheirus

To view the range of Collecta scale models available including the 1:40 replica of Deinocheirus: Collecta Scale Models of Prehistoric Animals

Those Plucky Placoderms

Armoured Fish Made a Significant Contribution to Vertebrate Evolution

The Placoderms were a hugely diverse and very successful group of fishes, whilst they lasted. For in terms of this groups’ persistence, in geological terms they make a relative short appearance in the history of life on Earth.  As a group the Placoderms were around for approximately sixty-five million years, not a bad innings but nothing like the longevity of other types of fish such as the sharks, rays and certain Actinistians, the Coelacanth for example.  The Placoderms, or to be more correct, the Class Placodermi first evolved in the Late Silurian and they disappear from the fossil record at the end of the Devonian Period.

Perhaps the most famous Placoderm is the giant predator Dunkleosteus.  Several species are known and with some specimens estimated to have reached lengths of around ten metres or more, at the time, (Dunkleosteus lived towards the end of the Devonian something like 370 – 360 million years ago), this fish would have been one of the largest vertebrates ever to have evolved.

Dunkleosteus – An Illustration

Fearsome marine predator of the Late Devonian.

Fearsome marine predator of the Late Devonian.

Picture Credit: Everything Dinosaur

Dunkleosteus may have looked like a typical Placoderm with its head and thorax covered in articulated armour plate, but the Placodermi, it turns out are being seen as one of the most important group of vertebrates to have existed  It is not just because they evolved into the likes of Dunkleosteus, regarded by many as the world’s first, vertebrate, super-predator, but this group of armoured fishes seems to have achieved a number of “firsts” in terms of the Chordata (animals with a spine or spine-like structure in their bodies).

Firstly, palaeontologists have found a number of fossils that suggest that early members of the Placodermi were amongst the first types of vertebrate to evolve a jaw.  Recently, Everything Dinosaur wrote a short article about a remarkable fossil discovery form China which reveals some remarkable features: A Jaw Dropping Discovery.

In addition, although the majority of Placoderms seemed to have been poor swimmers, with most of them living close to the bottom, a number of families were active and nektonic, indeed these types of fish were the first to evolve paired pelvic fins, a fishy equivalent of legs, although not connected with the spine.  Paired pelvic fins are an anatomical feature found in most types of extant fish today.

Those plucky Placoderms may have been amongst the first types of animal to develop teeth.  Recently a team of scientists from Australia and Bristol University studying fossilised remains of Placoderms from Western Australia found evidence of the first types of teeth, teeth with a structure very similar to our own.  To read more about this: The Origins of a Toothy Grin

Fossils from the same rocks (Go Go Formation) western Australia gave palaeontologists a remarkable insight into the reproductive strategies of many types of ancient fish.  One species of Placoderm, known from just a single fossil specimen represents the oldest example of a vertebrate capable of giving birth to live young (viviparity). Materpiscis attenboroughi was a small, bottom of the reef dwelling fish whose fossilised remains preserved in a limestone nodule showed evidence of an embryo and an umbilical cord.  This was evidence of internal fertilisation within the fossil record and the oldest known case of viviparity.

Materpiscis attenboroughi – A Remarkable Placoderm

Materpiscus means "Mother Fish".

Materpiscus means “Mother Fish”.

Picture Credit: Museum Victoria

The remarkable Placodermi may have just added another evolutionary “first” to their string of impressive attributes.   A scientific paper published in the journal “Nature” provides details on a fossil discovery that hints at the very first example of copulation amongst vertebrates.  The international team of researchers that led the study into the Antiarch (an-tee-arc) Placoderm called Microbrachius dicki state that this was the earliest animal known from the fossil record to stop reproducing by spawning (external fertilisation).

Professor John Long (Flinders University, South Australia), was the lead author of the academic paper.  The Professor, a renowned expert on Devonian fishes had earlier worked on Materpiscus attenboroughi.  The fossils of M. dicki are relatively common.  This small freshwater Placoderm grew to about ten centimetres in length and lived around 385 million years ago.

Professor Long Explains the Key Points of the Research

Studying Placoderms and other Devonian fish.

Studying Placoderms and other Devonian fish.

Picture Credit: Flinders University

Commenting on the research, Professor Long stated:

“We have defined the very point in evolution where the origin of internal fertilisation in all animals began.  That is a really big step.”

A close inspection of a fossil revealed that one of the Microbrachius specimens had a peculiar “L-shaped” appendage.  Further study revealed that this was the male fish’s genitalia.

The Professor pointed out:

“The male had large bony claspers, These are the grooves that they used to transfer sperm into the female”.

On the other hand, the females had a small bony structure at the rear that helped to lock the male organ in place during mating.  Constrained by the anatomy, the fish probably had to mate side by side, a sort of “square dance position” as described by the researchers.

An Illustration Showing the Proposed Mating Position of M. dicki

Mating "square dance" style.

Mating “square dance” style.

Picture Credit: Flinders University/Nature

However, copulation using this method does not seem to have stayed around for very long in these Devonian fish.  As fish evolved, they reverted back to external fertilisation (spawning), whereby male and females release sperm and eggs respectively into the water and fertilisation relies more on chance.  It took several more millions of years before the ancestors of today’s sharks and rays evolved copulation.

The Placodermi may be most famous for the likes of Dunkleosteus, but scientists are beginning to realise that these strange, armoured fish may have contributed much more to the evolution of the vertebrates than just the first, back-boned  super-predator!

Nosing Around Dinosaurs

New Study Sniffs Out Details of the Pachycephalosaur Nose

A study into the nasal passages conducted by a team of scientists from Ohio University suggests that certain types of dinosaur used their complicated noses to help cool their brains as well as to enhance their ability to smell.  The study, which focused on specimens from the Pachycephalosauridae family (the bone-heads), involved the development of computer models derived from CT scans of fossilised skulls in order to map the airflow in and out of a dinosaur’s snout.  Palaeontologists have known for some time that a number of different types of dinosaur had very complex nasal passages.  The nasal region although mostly associated with breathing (respiration), also plays an important role in helping to define and enhance a creature’s sense of smell.  In addition, the ability to bring in air at an ambient temperature into the skull may have a function in helping the brain to keep cool.  In the Late Cretaceous of North America, Pachycephalosaurs may have had small brains in their heavily armoured skulls but they did not want them to cook inside those thick heads.

A Model of a Typical Member of the Pachycephalosauridae Family

Nosing around the nasal passages of dinosaurs.

Nosing around the nasal passages of dinosaurs.

Picture Credit: Everything Dinosaur

Lead author of the research, which has just been published in the academic journal “The Anatomical Record”, Jason Bourke (Ohio University) states:

“Figuring out what’s going on in their [dinosaurs] complicated snouts is challenging because noses have so many different functions.  It doesn’t help that all the delicate soft tissues rotted away millions of years ago.”

In order to gain an appreciation of the nasal passages of long extinct dinosaurs, the team examined the snouts of extant relatives of the Dinosauria, namely birds, crocodiles and other reptiles including lizards.  The study of fossil skulls of Pachycephalosaurs was supported by lots of dissections, blood-vessel injections to map blood flow as well as CT scans.  The researchers also relied upon computer models that provided a three-dimensional analysis of airflow.

A technique more commonly applied to the study of airflow in the aerospace industry, a technique called computational fluid dynamics was used to better understand how extant animals such as Alligators and Ostriches breathe.

As PhD student Jason Bourke explained:

“Once we got a handle on how animals breathe today, the tricky part was finding a good candidate among the dinosaurs to test our methods.”

The team turned to a family of bird-hipped dinosaurs known as the Pachycephalosaurs, the bone-headed dinosaurs.  These particular dinosaurs were chosen as a number of specimens were readily available to study in the United States/Canada and skulls attributed to several genera were known.   The thick skulls with their ornamentation may have been used  by these relatively small dinosaurs for head-butting or visual displays.  The skull bones, some of which are several inches thick, has helped to preserve details of the nasal passages which the scientists were able to map and analyse in great detail.

Getting Up a Dinosaur’s Nose

Airflow in the nasal passages in the Pachycephalosaur Stegosaurus validum is mapped.

Airflow in the nasal passages in the Pachycephalosaur Stegoceras validum is mapped.

Picture Credit: Ohio University/The Anatomical Record

One Pachycephalosaur that was studied was Stegoceras (S. validum) and the researchers were able to show that some of the airflow that they mapped would have carried odours to the olfactory region, helping to improve this dinosaur’s sense of smell.  In addition, the team tried to piece together the shape of the nasal concha, otherwise known as the turbinates, that help to direct and manage airflow through the nasal passage.  This small bone, superficially resembles a sea shell (hence the name) and the fossil evidence supports the presence of such a bone but it is not found in the Dinosauria fossil record (as far as we at Everything Dinosaur know).  As the researchers point out, there is the bony ridge preserved on Pachycephalosaur skulls that indicate its presence and when airflow models were created, the best and most efficient ones produced included a turbinate structure within the model.

Commenting on the research results, Jason Bourke stated:

“We don’t really know what the exact shape of the respiratory turbinate was in Stegoceras, but we know that some kind of baffle had to be there.”

Study co-author Ruger Porter (Ohio University), pointed out that turbinates may well direct air to the olfactory region, but they might have also played another critical role, helping to cool the brain or at least helping to conserve moisture that might have been lost during exhalation.

Porter pointed out:

“The fossil evidence suggests that Stegoceras was basically similar to an Ostrich or an Alligator.  Hot arterial blood from the body was cooled as it passed over the respiratory turbinates and then that cooled venous blood returned to the brain.”

Whether this new research supports the theory that these dinosaurs were warm-blooded (endothermic) is being debated, but it does suggest there was more going on within dinosaur’s noses than scientists had previously thought.  It is hoped that the research team will be able to apply their analytical methods to other types of dinosaur such as the Thyreophora (armoured dinosaurs), known for their notoriously complex nasal passages.  This research may also provide answers to the questions concerning the bizarre shape of many crests found in Lambeosaurine dinosaurs (duck-billed dinosaurs).

Giant Kangaroos Made for Walking

Giant Sthenurine Kangaroos Probably Walked Rather Than Hopped

The Pleistocene prehistoric fauna of Australia may not quite be as embedded into the public’s consciousness as the Woolly Mammoths, Cave Bears and Sabre-Toothed Cats that represent examples of European Pleistocene prehistoric animals, but if anything, ancient “Aussies” were even more amazing than the shaggy coated examples typical of the fauna of the western hemisphere.  In a new study, published in the on line academic journal PLOS One (Public Library of Science), a team of researchers propose that ancient, giant Australian Kangaroos were walkers rather than hoppers, making up part of a prehistoric fauna that was truly astonishing.

The Kangaroos in question are the heavy-weight members of the Sthenurinae (the short-faced kangaroos).  A sub-family of the Macropodidae (means “big feet”), the family to which all Kangaroos belong.  Following a rigorous comparative analysis, the research team conclude that these large animals, some of which stood over two metres tall, did not hop but were adapted to a pedestrian lifestyle, these animals were walkers.  Sadly, like most of Australia’s mega fauna these herbivores became extinct and did not make it into the Holocene.  The last of the Sthenurinae died out about 30,000 years ago, shortly before the last of the Neanderthals in western Europe.

A Comparison Between an Extant Sthenurinae Kangaroo (Sthenurus stirlingi) and a Large Extant Species

Both these types of Kangaroo can stand up to two metres tall.

Both these types of Kangaroo can stand up to two metres tall.

Picture Credit: Wells and Tedford, 1995.  Original artist Lorraine Meeker, American Museum of Natural History, with additional annotation from Everything Dinosaur

As for reasons for their extinction, that question remains to be answered, however, it is thought that the presence of man on the continent from around 60,000 years ago had a severe impact on the fauna of Australia.  Giant Short-faced Kangaroos such as Simosthenurus occidentalis (short-faced, strong tail, western Kangaroo), known from fossils found in south-western Australia, probably could not move very quickly and could be caught by human hunters.  The use of fire could also have devastated their forest habitats leaving these browsers with little food.

The research team was led by Professor Christine Janis, (Professor of Ecology and Evolutionary Biology at Brown University, Rhode Island, USA).  Over one hundred comparative measurements were made, comparing the skeletons of living and extinct Kangaroo and Wallaby types.  For Professor Janis, her eureka moment occurred in 2005.  She was examining the bones of a mounted skeleton of a Sthenurine Kangaroo in a Sydney museum when she noticed how inflexible the spine looked when compared to a modern-day counterpart.  The professor began to wander whether these Pleistocene roos moved in the same way as extant Kangaroos.

Working in collaboration with the papers co-authors, Borja Figuerido of the University of Malaga (Spain) and Karalyn Kuchenbecker, a former undergraduate at Brown University, the Professor spent several years examining the fossilised remains of extinct Kangaroos to determine their method of locomotion.  In the published account of their studies, the team hypothesise that in their motion the extinct Sthenurines were very different from large Kangaroos found today.  The scientific paper is intriguing entitled: “Locomotion in Extinct Giant Kangaroos: Were the Sthenurines Hop-Less Monsters?”.

Extant Kangaroos can hop very quickly and utilise this unique form of motion to cover vast distances very efficiently.  They can also move about on all fours as their front limbs are capable of helping to support bodyweight, an anatomical characteristic absent in the larger members of the Sthenurinae.  The tail of many  members of the Macropodidae is also able to bear weight, providing additional support for many Kangaroos and Wallabies.  The use of the tail as a fifth limb has been referred to as a “pentapedal” stance.  Extinct Kangaroos such as Sthenurus stirlingi seem to lack the flexible spine need to make leaps and bounds.  Their anatomy seems best suited to putting one foot in front of the other – a walking Kangaroo!

Sthenurines had proportionally bigger hip and knee joints.  The shape of the pelvic area differs significantly as well (see diagram above).  The Sthenurines had a broad and flared pelvis that would have allowed for proportionally much larger gluteal muscles than other Kangaroos.  Those muscles would have allowed them to balance weight over just one leg at a time, as do the large gluteals of humans during walking.  Unlike modern Kangaroos with their four-toed feet, the extinct Sthenurines had just one, massive toe on the end of each foot.  The research team conclude that when the anatomy of all the Macropodidae is considered, the “weird” ones are the extant species that hop.  They are very lightly built for their size and their preferred method of locomotion may not be typical for the group as a whole.  A bit like using the Cheetah as a template for all Felidae motion.

Commenting on the research Professor Janis stated:

“If it is not possible in terms of biomechanics to hop at very slow speeds, particularly if you are a big animal and you cannot easily do pentapedal locomotion, then what do you have left?  You have to move somehow.”

An over reliance on walking, which is not as efficient as hopping, might explain the demise of these Kangaroos about 30,000 years ago.  These animals might have been easier to catch so humans took a toll on the population.  Or as the climate became more arid, these walking Kangaroos were not able to migrate far enough to find new sources of food.

An Artist’s Impression of a Short-Faced Kangaroo

Short-faced Kangaroo a pedestrian.

Short-faced Kangaroo a pedestrian.

Picture Credit: Brian Regal

The research team admit that more evidence is required to back up their anatomical study.  Ideally, if a set of “walking Kangaroo” tracks could be discovered, that would add considerable weight to their hypothesis.

How Did Huge Sauropods Manage to Get Along Together?

Dietary Niche Partitioning Amongst the Sauropoda

A team of British scientists have been tackling one of the biggest puzzles in palaeontology and a sophisticated analysis of dinosaur skull bones might just have helped them solve a mystery of gigantic proportions.  Sauropods, that group of long-necked dinosaurs that include such famous creatures as Diplodocus, Brachiosaurus and Apatosaurus (formerly known as Brontosaurus), ate vast quantities of plant material.  These huge animals with many individuals exceeding twenty metres in length and weighing many times more than a bull African elephant, would have been capable of stripping an area of vegetation, but the fossil record shows that in many parts of the world, lots of different species of Sauropod seem to have co-existed.  The scientists, a joint research team from Bristol University and the Natural History Museum (London), propose that Late Jurassic Sauropod skulls became specially adapted to help them feed on different types of plant material.  In this way, the skull morphology helped the long-necked dinosaurs divide up the available food resources between them, therefore limiting the amount of direct competition.

Previous studies had shown that in areas where lots of different species of Sauropods co-existed their body shapes and ability to angle their necks may have allowed the development of different feeding strategies with each species preferring to feed on a particular part of the flora that was available.

Proposed Sauropod Feeding Strategies

Long necks for different feeding envelopes.

Long necks for different feeding envelopes.

Picture Credit: Everything Dinosaur

In the picture above, models made by Safari Ltd help to illustrate current thinking about the feeding adaptations of members of the Sauropoda.  Diplodocids such as Diplodocus and Apatosaurus with their very long necks and relatively horizontal feeding platforms probably specialised in feeding on ferns, cycads and plants that made up the vegetative understorey.  Whilst in the middle, dinosaurs such as camarasaurids a member of a different family of Sauropods called the Macronaria could feed on a wider range of plant material, cycads and seed ferns as well as being able to strip leaves off small trees.  The dinosaur in the bottom of the picture is a member of the Brachiosauridae (Brachiosaurus).  These dinosaurs had much longer forelimbs than hindlimbs and as a result, their heads were held much higher.  These dinosaurs probably specialised in feeding from the very tops of the tallest trees, parts of the vegetative canopy not available to other plant-eating dinosaurs (unless they knocked the trees down).  The tree in the picture is an Agathis conifer, a model also made by Safari Ltd.

To view Everything Dinosaur’s range of prehistoric plant models and dinosaurs (Safari Ltd): Carnegie Collectibles and Wild Safari Dinos Models

A Detailed Model of the Skull of Camarasaurus

Camarasaurus was probably the most common Sauropod living in the western United States during the Late Jurassic.

Camarasaurus was probably the most common Sauropod living in the western United States during the Late Jurassic.

Picture Credit: David Button

A spokesperson from Everything Dinosaur commented:

“Based on counts of the fossilised bones, Camarasaurus seems to have been the most common of all the different types of Sauropod known from the Morrison Formation.  Perhaps this dinosaur was more of a “generalist” when it came to diet.  A half-way house between the long-necked diplodocids and the giraffe-like brachiosaurids.  An ability to feed on a wide variety of plants, including the tougher plants not available to the likes of Diplodocus and Apatosaurus, could have led to this particular genus of long-necked dinosaur being one of the most successful in the Late Jurassic of the western North America, to the south of the Sundance Sea.”

Building on previous studies, the British team looked specifically at the Sauropod fauna associated with the Upper Jurassic Morrison Formation of the western United States.  At least ten different species of Sauropod are known from this formation, one of the most intensely studied fossiliferous formations in the Americas.  Although the Morrison Formation deposits represent a number of habitats, some of the most famous fossil beds such as those making up the Salt Wash Member indicate that some parts of the Morrison Formation represent deposits laid down in harsh, semi-arid environments, not the sort of place where one might expect vast numbers of different types of Sauropod.  Despite the harsh conditions, the fossil record shows that lots of different Sauropods co-existed.  When the diverse faunas of modern day Africa are considered, these habitats only support one truly huge, extant species – the elephant.  So how did the Sauropods get along with each other?

Bristol University’s PhD student David Button worked in collaboration with the Natural History Museum to examine how the skulls of different long-necked dinosaurs may have been adapted to help them feed on different types of plant.  Digital reconstructions were made of the skulls of Camarasaurus and Diplodocus using data compiled from Computerised tomography (CT scans).  From this data, a biomechanical model of the Camarasaurus skull was created and then this skull was compared to an existing digital model of the Diplodocus.  Finite Element Analysis (FEA), was used to assess the stresses that each skull could take.  FEA analysis is used in engineering to calculate loads and stress bearings in complex shapes, this research showed that the box-like skull of Camarasaurus gave this dinosaur a stronger bite.  Camarasaurus could have coped with tougher vegetation than Diplodocus.  The weaker bite and more delicate skull of Diplodocus would have restricted this animal to softer plant material such as ferns.  Diplodocus could have compensated for this to some extent by using its strong neck muscles to help detach plant material through movements of the head.

David Button concluded:

“Our results show that although neither could chew, the skulls of both dinosaurs were sophisticated cropping tools.  This study indicates that differences in diet between these two dinosaurs would have allowed them to co-exist.”

The research team used a number of biomechanical measurements from other Morrison Formation Sauropods to calculate the different types of feeding adaptations, providing evidence for different diets and overall a conclusion that dietary niche partitioning did occur in the Sauropoda.

Comparing the Skulls of a Typical Camarasaurid and Diplodocid

Analysis of fossil bone helped the researchers determine the size and location of jaw muscles.

Analysis of fossil bone helped the researchers determine the size and location of jaw muscles.

Picture Credit: David Button

In the picture above, the box-like skull of Camarasaurus is shown left (a) with a typical skull of a Diplodocus (b).

Co-author of the scientific paper, which has been published in the Proceedings of the Royal Society Biology, Professor Emily Rayfield (Bristol University) stated:

“In modern animal communities differences in diet such as this, termed dietary niche partitioning, allow multiple species to co-exist by reducing competition for food.  Although, dietary niche partitioning has been suspected between Morrison Formation Sauropods based on their structural features and patterns of tooth-wear, this is the first study to provide strong, numerical, biomechanical evidence for its presence in a fossil community.”

This new research may help palaeontologists to understand more about how the Sauropoda evolved.  Sauropods from the Dashanpu Quarry region of China dating from the Middle Jurassic may also show similar adaptations over skull morphology and bite strength as reflected in the research done on the slightly later Sauropods from the Morrison Formation.

In addition, this analysis may help scientists to unravel the mechanisms responsible for supporting the high diversities of mega-herbivores found in other Mesozoic and Cenozoic animal populations, particularly those in resource limited environments.

For related articles on Sauropod feeding strategies:

Ostrich Necks Provide Clues to Sauropod Neck Flexibility

Diplodocus Feeding – a biter or a comber?

Evidence for Seasonal Migrations Amongst Camarasaurids

Indonesian Cave Paintings Change Ideas About the Origin of Art

Oldest Prehistoric Cave Art in the World Perhaps – An Indonesian Cave Art Exhibition

The human ability to think in abstract terms is often cited as one of the key differences between our species and those in the rest of the animal kingdom.  Our love of art and visual depiction can be traced back to the Late Palaeolithic but the thought that since cave paintings are confined to France and Spain, therefore art began in Europe, has been challenged thanks to an amazing discovery on the Indonesian island of Sulawesi.

A joint Australian and Indonesian team of anthropologists have uncovered a series of ancient human hand stencils and paintings of animals in seven cave sites in the southern portion of Sulawesi island.  Although a rural location, these caves (Karst Maros) had been visited by a number of tourists and backpackers, but until now nobody knew just how old some of the paintings were.

A Number of Ancient Human Hand Stencils were Part of the Study

Ancient human "handy" work.

Ancient human “handy” work.

Picture Credit: Maxime Aubert

Archaeologists and palaeoanthropologists had long been puzzled by the appearance in southern Europe around 40-35 thousand years ago of a rich and varied range of artwork, including rock paintings and carved figures, but the absence or scarcity of similar art found elsewhere in the world.  Homo sapiens migrated into southern Asia and the Far East but little evidence of any form of culture in terms of works of art has been left behind on these migration routes.

Using a dating method that is based on the radioactive decay of uranium to thorium in small mineral growths that had formed on the paintings, the scientists were able to determine the minimum age of the paintings.  One hand stencil has been dated to circa 39,900 years ago, making it the oldest human hand print known to science.  A painting of a wild pig, an animal probably hunted by these ancient humans, has been dated to at least 35,400 years ago.  The artwork and images had been created by using red ochre, the materials and painting techniques used seem to be very similar to those found in caves of a similar age in western Europe.

Commenting on the significance of this study, Maxine Aubert of Griffith University (Queensland), one of the researchers stated:

“It was previously thought that Western Europe was the centre piece of a symbolic explosion in early human artistic activity such as cave painting and other forms of image making, including figurative art, around 40,000 years ago.”

This new research suggests that the rock art traditions seen on Sulawesi are at least as old as the oldest known European art.   One of the implications of this new study is that it has now been demonstrated that humans were producing very similar types of rock art by 40,000 years ago but at opposite ends of the Pleistocene Eurasian world.

The Oldest Human Hand Stencil and the Animal Drawing

Cave paintings at least 35,400 years old with hand stencils at least 39,900 years old.

Cave paintings at least 35,400 years old with hand stencils at least 39,900 years old.

Picture Credit: Maxime Aubert (green highlighting circles added by Everything Dinosaur)

The artwork is very faded in the above photograph, so we have circled in green the rock art that was studied.  It is feared, that just like the cave art in some European caves, modern pollution could damage these ancient Indonesian drawings.

To read an article about the damage being done to cave paintings in Europe due to rising levels of fungi: Cave Paintings Might Be Lost Forever

The scientists hope to use this radioactive dating technique to accurately date other rock art sites in Asia and Australia.  By doing this they hope to better understand human migration and the movement of abstract ideas through the ancient population as it migrated eastwards.

Venezuela’s Second Dinosaur – Tachiraptor

Tachiraptor admirabilis – Tracing the Origins of the Big Theropods

Venezuelan dinosaurs must be a bit like buses, you wait for years for one to come along and then two arrive almost simultaneously.  Back in August of this year, we reported on the discovery of Venezuela’s first ever dinosaur, a small, plant-eater from the very Early Jurassic.  This dinosaur was named Laquintasaura venezuelae and it was the first dinosaur named from the north of South America.  Two months later and a second paper about a new Venezuelan dinosaur, this time a meat-eater, is about to be published.  Say hello to Tachiraptor, a bipedal, fast-running carnivore that may very well have been a predator Laquintasaura.

An Artists Impression of Tachiraptor Attacking Laquintasaura

A carnivorous Tachiraptor attacks a flock of Laquintasaura dinosaurs.

A carnivorous Tachiraptor attacks a flock of Laquintasaura dinosaurs.

Picture Credit: Maurílio Oliveira

The illustration above shows the fearsome, newly described Theropod Tachiraptor attacking a small flock of primitive, Ornithopod dinosaurs (Laquintasaura), whilst a couple of alarmed Rhamphorhynchid Pterosaurs take flight.

To read more about Laquintasaura: Laquintasaura – What Does it All Mean?

The artist has chosen to illustrate both the dinosaurs in the picture as feathered creatures.  During the Early Jurassic, around 200 million years ago, approximately the time that both Tachiraptor and Laquintasaura lived, Venezuela was close to the equator.  The sandstone deposits in which the fossils were found indicate a flood plain environment.  This flood plain was surrounded by harsh, inhospitable deserts that probably did not support much vertebrate life.  Day temperatures would have been high, but just like many desert areas close to the equator today, at night, temperatures would have plummeted.  Relatively small animals like Tachiraptor and the even smaller Laquintasaura may have sported a coat of insulating feathers to help keep them warm.  A recent dinosaur discovery from Siberia (Kulindadromeus), suggests that many early types of dinosaur may have been feathered, although no fossil evidence for feathers in both Laquintasaura and Tachiraptor has been found (as far as we at Everything Dinosaur know), it seems reasonable at this point to depict these Early Jurassic members of the Dinosauria as feathered.

To read more about the discovery of Kulindadromeus: Information on Early Feathered Dinosaurs

If Laquintasaura has been described as being about the size of a red fox (Vulpes vulpes), then to keep the canine motif, the predatory Tachiraptor may have been around the size of a grey wolf (Canis lupis), with a total length of 1.5 metres.  The size estimate is based on the two fossil bones ascribed to this genus discovered so far.  The fossils represent lower leg bones from two individuals, the research team responsible for the excavation and study of this new Theropod (Universidade de São Paulo), Brazil found the bones back in 2013 in the same cutting between the towns of La Grita and Seboruco where the fossils of Laquintasaura had been found.  Tachiraptor admirabilis honours the Venezuelan state of Táchira, the species name is in commemoration of the 1813 campaign led by Simón Bolívar to form a republic (known in Spanish as the Campaña Admirable – admirable campaign).

Tachiraptor – The Name Means “Robber of Táchira”

An agile, lithe predatory dinosaur.

An agile, lithe predatory dinosaur.

Picture Credit: Everything Dinosaur

Dr. Max Cardoso Langer, of the palaeontology department of São Paulo University, one of the scientists involved with this study, explained that the fossil material consisted of a tibia and a second lower leg bone that was fragmented.  However, the locality and morphology of these scrappy fossils gave the research team the confidence to assign a new genus.  Although the exact taxonomic affinity within the Theropoda could not be established as the fossils date from the Hettangian faunal stage, it was most likely a basal Theropod.

A spokesperson from Everything Dinosaur stated:

“Very little is known about the dinosaurs that lived in the very Early Jurassic.  When Tachiraptor and Laquintasaura roamed Venezuela some 200 million years ago, the world was recovering from a mass extinction event.  The fossils of these two dinosaurs will help palaeontologists to understand better the implications for the Dinosauria after the Triassic/Jurassic mass extinction.”

Dinosaur Tracks in Danger of Becoming Extinct

Cal Orck’o Dinosaur Tracks Threatened

To the north-east of the city of Sucre in central Bolivia lies one of the most remarkable fossil sites anywhere in the world. The Huellas de Dinosaurio de Cal Orck´o which translates as the “dinosaur footprints on the lime hill”.  For here, preserved on a sheer slope, are the fossilised tracks of dinosaurs, more than 5,000 individual prints, in excess of 350 trackways providing a spectacular trace fossil record of life in the Late Cretaceous some 68 million years ago.  However, extraction of material to support the local cement works could be endangering the entire site according to local conservationists.

The Spectacular Dinosaur Tracks Exposed at Cal Orck’o

View from the viewing platform from the dinosaur museum.

View from the viewing platform from the dinosaur museum.

Picture Credit: Google Maps/AFP

 Although less famous than the Lark Quarry site (Australia) and the Sauropoda tracks found in Gansu Province (China), the Bolivian site represents one of the biggest, if not the biggest collection of dinosaur footprints discovered to date.   At least eight types of dinosaur trackways have been identified.  There are the huge footprints of gigantic Titanosaurs, tracks made by some of the largest land animals that ever existed.  Many of the individual prints measure more than 100 centimetres in diameter and indicate dinosaurs around twenty metres or more in length.  There are also tracks of Ornithopods and ankylosaurids.  Meat-eaters are represented too, the largest three-toed tracks identified as having been made by Theropod dinosaurs most probably represent tracks made by abelisaurids, the nearby Parque Cretácico (Cretaceous Park) contains a number of life-size, colourful replicas of the dinosaurs that once roamed this part of Gondwanaland.

Photograph of a Typical Late Cretaceous Abelisaurid (Carnotaurus Probably)

Cretaceous Park Museum illustrates the prehistoric fauna.

Cretaceous Park Museum illustrates the prehistoric fauna.

Picture Credit: Thewanderingscott.com

 The park and viewing platforms were opened in 2006, a collaboration between a number of scientific institutions including the Natural History Museum of Basel (Switzerland) whose research teams did much to document and map the tracks between 1998 and 2003, with the support of the Bolivian Government.  Fossilised tracks had been found by cement industry workers and quarry men for many years before the discovery in 1994 of the extensive trackways.  The cliff site and the nearby Cretaceous Park attract in the region of 120,000 tourists each year.

However, the nearby cement factory could be endangering the fossilised footprints as the quarrying of limestone takes place nearby.  The quarry work and frequent dynamiting of rock faces to expose new material could be undermining the entire site and making the sixty-eight million year old fossils in danger of collapse.

Elizabeth Baldivieso, the administrator of Parque Cretácico stated:

“The cliff has been quite affected by the many years of extraction of raw material.”

The regional Tourism and Cultural Secretary, Juan Jose Padilla disagrees, referring to Elizabeth Baldivieso’s description as “somewhat alarmist”.  The cement company, Fancesa jointly owned by a local university, the city and regional administrators has vowed to protect the site.

Pointing Out a Set of Dinosaur Tracks on the Near Vertical Surface
Dinosaur tracks on the near vertical cliff face.

Dinosaur tracks on the near vertical cliff face.

Picture Credit: Google Maps/AFP

The dinosaur tracks appear to indicate that these ancient creatures were climbing an almost sheer vertical cliff face.  However, back some 68 million years ago, the landscape was flat and muddy.  Over time plate movements pushed up the floodplain creating the near vertical trackways which stretch for around fifteen hundred metres or so.

This location was proposed as a UNESCO World Heritage site in 2009, but the cement company opposed the application and it was eventually turned down.  Campaigners are hoping to re-apply for UNESCO World Heritage status in 2015.  This would provide much greater protection to the fossil trackways and we at Everything Dinosaur wish the Bolivian Government and conservationists every success with the re-submission.

To read an article written by Everything Dinosaur about the discovery of some Early Cretaceous dinosaur footprints in Bolivia: Farmer Describes Dinosaur Tracks to Scientists

Extensive Dinosaur Bone Bed Discovered in Northern Mexico

Joint Mexican and German Field Team Discover Extensive Dinosaur Remains in Chihuahua Desert

The Chihuahua Desert covers much of northern Mexico and stretches across the border into the United States.  At around  160,000 square miles it is the second biggest desert in North America, the United Kingdom would fit into this semi-arid and true desert habitat one and a half times.  This vast area is widely recognised as supporting one of the most diverse and speciose desert ecosystems on Earth, it is ironic then to report that a team of palaeontologists have discovered a site in the Chihuahua Desert that might represent one of the most concentrated areas of Late Cretaceous dinosaur bones anywhere in the world.

Mapping and Recording Fossil Evidence

A dinosaur bone bed

A dinosaur bone bed

Picture Credit: Reuters

A field research team exploring Upper Cretaceous strata have reportedly found the remains of at least fourteen dinosaurs on a site measuring fifty by two hundred metres.  Such concentrations of prehistoric animal bones although rare, have been found elsewhere in North America, perhaps most famously in Canada where a number of single species Ceratopsian bone beds have been excavated, but we at Everything Dinosaur are unaware of such a concentration in Mexico.  The research team consists of scientists from the University of Heidelberg, the State Museum of Natural History in Karlsruhe and the Desert Museum in Saltillo (30 miles south-west of Monterrey, Mexico).  Although there has been no data published as yet confirming the identity of these animals to the genus level, we suspect that much of the material may represent fossils of duck-billed dinosaurs.  In a statement, reported in a German newspaper, the field team have announced the discovery of at least fifteen more specimens at a nearby location, just a few miles away from the concentration.  Both sites represent riverine deposits and along with the fifteen other, more scattered specimens, the scientists have found fossils of turtles, small crocodilians and the teeth of a number of Cretaceous mammals.

During the Late Cretaceous much of northern Mexico was an extensive flood plain and low lying coastal area with the Western Interior Seaway to the east and the Atlantic Ocean to the south.  This landmass formed part of the southern provinces of the island continent of Laramidia which stretched from Mexico in the south up to the northern tip of Alaska.

A Bone Bed Containing Extensive Dinosaur Fossil Remains

Bone beds such as this can tell scientist a lot about a particular species of dinosaur.

Bone beds such as this can tell scientist a lot about a particular species of dinosaur.

Picture courtesy of Alamlar.ir newspics

To read about the discovery of a huge dinosaur “graveyard” in Switzerland: Dinosaur “Graveyard” Discovered

Commenting on the on-going field work, palaeontologist Eberhard Frey (State Museum of Natural History in Karlsruhe) said:

“There is a huge delta here with several rivers flowing into the Gulf of Mexico.  This was a very active ecosystem.  We have not only found dinosaur bones, but also four different species of turtle, remains of very small crocodiles and the teeth of early mammals”.

Trace fossils have also been found in the area including some three-toed footprints indicating the presence of a large Theropod dinosaur in the locality.

Außerplanmäßiger Professor Frey added:

“This week we have found three teeth of Theropods.  These are diagnostic features that allow us to determine the species more precisely.”

An Everything Dinosaur team member stated that it was likely that more information about the fossils will be published next year as the field team expected to return to the excavation site in 2015 to further map the area, remove more fossil material and examine the surrounding area.

Scientists have learned a great deal about the flora and fauna of the this part of the continent of Laramidia in recent years.  It was just six years ago that scientists, including researchers from the Desert Museum in Saltillo published a paper on the first, unique dinosaur genus to have been identified in Mexico.

To read more about this research: Viva Mexico! New Species of Duck-Billed Dinosaur Described

Last week, a new species of armoured dinosaur (Ziapelta sanjuanensis) was announced.  The fossils of this plant-eating member of the Ankylosauridae family were discovered across the border in the southern United States (New Mexico)

To read more about this fossil find: New Armoured Dinosaur from New Mexico

New Armoured Dinosaur from New Mexico

Ziapelta sanjuanensis  From New Mexico but Closely Related to Canadian Ankylosaurs

For some strange reason, the Ankylosaurs don’t seem to be held in quite the same awe as the horned dinosaurs by most members of the public.  We at Everything Dinosaur have our own theory about this.  The horned dinosaurs are much easier for the lay person to recognise.  There is the spectacular spiked frill of Styracosaurus, the peculiar nasal boss of Pachyrhinosaurus, a dinosaur genus which came to greater prominence with the “Walking with Dinosaurs in 3-D” movie.  Then there is of course, the most famous horned dinosaur of all – Triceratops (three horned face).  Members of the Ankylosauridae tend to have the same basic body plan.  They have broad rumps, bony clubs on the end of their tails and of course, all that body armour.  Model makers often find it difficult to distinguish different armoured dinosaurs.  For example, the Saichania replica made by Schleich, to the uninitiated, resembles Ankylosaurus.

The Saichania Model made by Schleich

Saichania means "beautiful"

Saichania means “beautiful”

Picture Credit: Everything Dinosaur

When it comes to films and television documentaries, the Ankylosaurs are rarely given star billing.  So today, in our own small way, we are going to champion the Late Cretaceous armoured dinosaurs by discussing the newest member of their family – Ziapelta, from the San Juan Basin of north-western New Mexico.  The fossils of Ziapelta consist of elements of the skull and incomplete neck rings of spiky bone and fragments of the famous, scaly Ankylosauria body armour (osteoderms).  The material was discovered in 2011 by Robert Sullivan, subsequently excavated by Dr. Sullivan and colleagues and then stored at the New Mexico Museum of Natural History and Science.  Once extracted from its silt and sandstone matrix, the scientists had enough fossil evidence to assign these fossils to a new genera.  A thorough exploration of the surrounding area produced no further post-cranial material.  It seems the head and neck of this armoured dinosaur were separated from the rest of the body prior to burial.  How this came about, one can only speculate.

The fossils were collected from the De-na-zin Member of the Kirtland Formation which as been dated to around 74 to 72 million years ago.  At perhaps as much as six metres long, the herbivorous Ziapelta would have been a very formidable adversary for even the largest tyrannosaurid.

An Illustration of Ziapelta (Z. sanjuanensis)

New Armoured Dinosaur from New Mexico

New Armoured Dinosaur from New Mexico

Picture Credit: Sydney Mohr

To the lay person, the spiky-looking Ziapelta might just look like any other Ankylosauridae, so let’s explain why the skull and neck material have allowed scientists to erect a new genus of armoured dinosaur.  Firstly, elements of the skull have been found, the skull morphology (shape) and composition can be very helpful when looking to identify an animal new to science, dinosaurs included.  Co-author of the scientific paper, which is published in the on line academic journal PLOS One, Victoria Arbour commented:

“The horns on the back of the skull are thick and curve downwards and the snout has a mixture of flat and bumpy scales – an unusual feature for an ankylosaurid.”

Dr. Arbour (University of Alberta) is a renowned expert on all things Ankylosaur, she was invited to examine the fossils along with PhD student Mike Burns (University of Alberta).  The scientists concluded that unlike the armoured dinosaur Nodocephalosaurus kirtlandensis, which is also known from the San Juan Basin and is believed to be related to Asian genera of the Ankylosauridae, Saichania for example, Ziapelta was more closely related to the ankylosaurids of Canada.

The Formidable Spiky Cervical Rings of Ziapelta

Bony and spiky neck armour of Ziapelta.

Bony and spiky neck armour of Ziapelta.

Picture Credit: PLOS One

Dr. Arbour stated:

“Bob Sullivan, who discovered the specimen, showed us pictures and we were really excited by both its familiarity and its distinctiveness.  We were pretty sure right away we were dealing with a new species that was closely related to the Ankylosaurs we find in Alberta.”

Ziapelta has another unusual feature that distinguishes it from other ankylosaurids, a feature that we at Everything Dinosaur find quite endearing considering the size and fearsome nature of these reptiles.  The layout of the scales that make up the top of the skull are often very distinctive.  In the case of Ziapelta, it has a large triangular-shaped scale on the tip of its snout, in contrast to many other ankylosaurids which have a six-sided scale on their snouts

Views of the Skull Fossil of Ziapelta (Z. sanjuanensis)

Views of the skull fossil material of Ziapelta.

Views of the skull fossil material of Ziapelta.

Picture Credit: PLOS One

The photograph above shows various views of the holotype skull material, A – dorsal view (view from the top), B = ventral view (viewed from underneath), C = anterior view (view from the front), D = occipital view (viewed from the rear) and finally E – left lateral view (view of the left side of the skull).  In photograph A, we have highlighted in red the outline of that large triangular scale on the snout (referred to as mnca - median nasal caputegulum to use the formal scientific term).

Dr. Arbour put it very succinctly stating:

“There’s also a distinctive large triangular scale on the snout, where many other ankylosaurids have a hexagonal scale.”

The University of Alberta scientist has specialised in studying Ankylosaurs, especially those specimens which are known from the Late Cretaceous of North America.  Back in 2013, Everything Dinosaur reported on Dr. Arbour’s research into the Ankylosauridae which was helping to redefine this family of dinosaurs.

To read more about this research: When is a Euoplocephalus a Euoplocephalus?

Ankylosaurid fossils make up a small, but significant proportion of the Dinosauria fossil assemblage of southern Alberta, but to date, no ankylosaurid material has been found in the Horseshoe Canyon Formation (lower parts of this formation, the Strathmore and the Drumheller Members) of Alberta.  These rocks are roughly the same age as the strata in which the fossils of Ziapelta were found.  This New Mexico armoured dinosaur is helping palaeontologists to plug a gap in the record of ankylosaurid fossils known from North America.

Dr. Arbour explained:

“The rocks in New Mexico fill in this gap in time, and that’s where Ziapelta occurs.  Could Ziapelta have also lived in Alberta, in the gap where we haven’t found any Ankylosaur fossils yet?  It is possible, but in recent years there has also been increasing evidence that the dinosaurs from the southern part of North America – New Mexico, Texas and Utah, for example, are distinct from their northern neighbours in Alberta.”

There is a lot of evidence to support the idea of “dinosaur provinciality” in North America.  It seems that although the overall mix of dinosaurs was about the same in the regions, the actual genera that made up the dinosaur populations differed markedly.  How or why these distinct faunas came about remains something of a mystery.  The discovery of Ziapelta may help to add more pieces to the picture as palaeontologists strive to solve this puzzle.

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