Aardonyx celestae – The Start of Something Big (Sauropoda)

Scientists have published a report into a recently discovered set of fossilised dinosaur bones that provide clues regarding the evolution of the largest land animals ever to walk the Earth.

A paper written by a joint team of South African and U. S. based scientists on a new dinosaur species, believed to be the ancestor of the sauropods has been published in the online scientific journal Proceedings of the Royal Society of Biology.

This new species of dinosaur has been classified as a basal sauropod, a member of the Sauropodomorpha, a group of primitive herbivores from which the huge giants such as Apatosaurus, Diplodocus and  Brachiosaurus evolved.  This new dinosaur has been named Aardonyx celestae, the name is a combination of Afrikaans and Greek which means “Earth Claw”.

Fossilised Dinosaur Bones

The fossils were found in the Northern Free State of South Africa, near the small town of Senekal, in the Bethlehem region.  The fossils represent at least two individuals, both believed not to be fully grown when they died.  The largest specimen is estimated to have measured approximately 7 metres in length.

The fossils reveal a number of characteristics that indicate that this species may have been a transitional species. Elements of the anatomy are characteristic of the larger, later sauropods.

Matthew Bonnan, a vertebrate palaeontologist at Western Illinois University, one of the authors of the research paper states that this relatively small dinosaur was a sauropod ancestor with features foreshadowing those of its more famous descendants such as Apatosaurus.

Early Jurassic Fossils

The fossils have been dated to the very Early Jurassic, approximately 195 million years ago (Sinemurian faunal stage).  The sauropodomorphs were the first plant-eating dinosaurs, the earliest forms evolved in the Middle Triassic but the fossil record for Triassic sauropodomorphs is extremely poor.  One of the oldest known sauropodomorphs was Saturnalia, fossils of which have been found in Brazil.

During the Triassic and Early Jurassic the continents we know today as South America, Antarctica, Australia and Africa were joined together to form one single land mass – Gondwanaland.  Theoretically, a primitive dinosaur called have walked from South America to South Africa, perhaps the sauropodomorphs evolved in the Southern Hemisphere.

Aardonyx celestae

In images showing this new dinosaur, the bones shaded in white indicate those elements of the skeletons that have been recovered from the dig site.  The discovery of most of the skull has helped scientists to understand the taxonomic relationship between this Early Jurassic dinosaur and its descendants.

When Matthew and his colleagues studied the length of the rib bones and compared these to the length of the forelimbs, they concluded that the front legs of this dinosaur were capable of bearing considerable weight but for the majority of the time this dinosaur may have adopted a bipedal approach.  In essence, Aardonyx may have been a facultative biped, an animal that walked around on its hind legs, but would adopt a quadrupedal stance (all fours) as and when required.

In biology, the ability to undertake an activity by desire rather than obligation is referred to as facultative.  In this case, the bipedal A, celestae could walk on all fours if it chose to do so.  The later much heavier sauropods were so large they rarely if changed their quadrupedal stance.

Pits on the Jawbone

The large number of small pits along the creature’s jawbone suggests that Aardonyx lacked a fleshy cheek that would have constrained how far the creature could open its mouth.  Its wide gape, Bonnan and his colleagues suggest, enabled this dinosaur to grab large mouthfuls of foliage with each bite.  Also, a strip of bone that ran along the base of the peg-like teeth braced them against side-to-side forces produced when the dinosaur stripped foliage from trees.

Commenting on these characteristics, Adam Yates, a palaeontologist at the University of the Wiwatersrand in Johannesburg and lead author in this study stated:

“These features are the first steps on the road to the specialised, bulk-browsing herbivory seen in sauropods.”

The shaded parts of the diagrams supplied indicate those parts of the skull that have been discovered to date.  Scientists hope that these South African fossils will shed more light on the evolution of the sauropods.

Sauropodomorphs

It is hoped that more information on the sauropodomorphs will be revealed when the fossilised remains of Thecodontosaurus are prepared and properly studied.  The best specimen of this English sauropodomorph that dates from the Middle to Late Triassic has not been removed from its rock matrix.  However, a recently awarded Heritage Lottery Fund (HLF) grant will enable a complete preparation process to take place.

To read more about the work on Thecodontosaurus: Bristol’s Dinosaur Thecodontosaurus to Rise Again Thanks to Grant.

The size and shape of muscle attachments on this dinosaur’s femur indicates that the leg muscles were powerful but that the creature was, for the most part, rather slow-moving, a characteristic certainly shared with its extremely large descendants.  For instance, estimates of the top speed of a dinosaur as big as a Brachiosaurus have been as low as 7 kmh, that is slower than most people walk.  However, if you are the size of a three-story house running away is not the best defensive option, not many meat-eaters would be bold enough to tackle a gigantic herbivore such as a Brachiosaurus.

Matthew Bonnan stated:

“This dinosaur wasn’t running a lot.  The overall shape of Aardonyx and particular aspects of its limbs, teeth and jawbone are anatomical hints of things to come in later sauropods.”

Commenting on the discovery, Paul Upchurch, a vertebrate palaeontologist at University College, London said:

“This is a very interesting animal.  The large number of bones recovered from various parts of the skeleton provide a good idea of what the creature might have looked like.”

He went on to add:

“Many of the features expected in a sauropod ancestor are present in Aardonyx, but they’re combined in an unusual mosaic.  For instance, although the creature had a wide gape that would have allowed it to grab large mouthfuls of vegetation, it had a narrow snout, unlike the broad U-shaped snout seen in most true sauropods.  This animal is expected, but in an unexpected sort of way.” 

The Hunt for More Primitive Sauropodomorphs

Scientists have predicted that more primitive sauropodomorphs will be found, hopefully these new South African discoveries will help shed light on the evolution of the Sauropoda and may help palaeontologists to understand the evolution of the ornithischian dinosaurs as well as the saurischian dinosaurs.   The most primitive of all dinosaurs, the ancestor of all that was to follow; was probably a small, gracile, bipedal, meat-eater.

Fossils of primitive members of the Sauropodomorpha will help scientists to learn more about the evolution of different types of dinosaur and the radiation of different forms that occurred during the Triassic/Jurassic.

To view replicas and models of sauropod dinosaurs: Prehistoric Animal Models and Figures.

Dinosaur Footprints found on New Zealand’s South Island

Fossil evidence of dinosaurs discovered in New Zealand. Dinosaur footprints have been discovered in New Zealand.

New Zealand a land of Maoris, great rugby, sheep and beautiful landscapes has some of the most ancient fern forests of anywhere in the world.  Many people know that much of the Peter Jackson directed trilogy “The Lord of the Rings” was filmed in New Zealand, the mountains and lakes providing an ideal backdrop for orcs, hobbits, wizards and other such strange creatures.  New Zealand provided a number of locations for the ground breaking BBC TV series “Walking with Dinosaurs”, but the dinosaur fossil record for that country is extremely poor.

Dinosaurs

Until recently, dinosaurs were known from only a few fragmentary fossils, all of which were associated with North Island.  To read an article about the discovery of titanosaur fossils in New Zealand: Titanosaur Fossil Discovered in New Zealand.

Scientists have discovered the first evidence that dinosaurs roamed the South Island of New Zealand with 70-million-year-old footprints found in six locations.  These are believed to be the first dinosaur footprints found in New Zealand.  For scientist Greg Browne (a sedimentologist), who made the discoveries this marks a special day for him, as he has proved that dinosaurs roamed parts of South Island more than 70 million years ago.  As we at Everything Dinosaur, recall, and despite the fact that we would be the first to admit that our knowledge of the geology of New Zealand is very poor.  By the Late Cretaceous, the time these prints were made, New Zealand had been separated from Australia for many millions of years.

It was an island but it looked nothing like the New Zealand seen on maps today.  Rising sea levels and volcanic activity has dramatically altered the shape of the country over the late Mesozoic and Cenozoic.  Indeed, as far as we know, most of the country was under the sea for most of the time from the Late Cretaceous until the present day.

The prints, were found in the remote Whanganui Inlet in the northern part of South Island , near to the settlement of Nelson.

Dinosaur Footprints

Pictures show soft debris around a dinosaur footprint, which can be made out at the bottom right-hand side of the photograph, is being brushed away.

The prints are spread over an area of approximately 10 kilometres and in one location there are up to twenty individual impressions.  It is believed the prints belong to a type of long-necked dinosaur a titanosaur.  Titanosaurs were among some of the largest animals to ever live and are believed to be the largest animals ever to walk on land.  Greg Browne and his team cannot be certain as to which type of dinosaur species or genus made the prints but the shape and size of the impressions does indicate a small titanosaur of some sort.

An Illustration of a Typical Titanosaur (Saltasaurus)

A drawing of Saltasaurus.

Picture credit: Everything Dinosaur

To view scale models of titanosaurs and other prehistoric animals, take a look at the Wild Safari Prehistoric World model series: Safari Ltd. Wild Safari Prehistoric World Models.

Aware of the controversial nature of his discovery, Greg carefully considered all possible geological and biological explanations for the features in the rock and was able to rule them out one by one, before coming to his conclusion.  His investigations involved him comparing the New Zealand impressions with known dinosaur footprints in similar aged rocks from elsewhere in the world.

The footprints were made in beach sands and were probably quickly covered and preserved by mud from subsequent tides.

Greg went on to comment:

“What makes this discovery special is the unique preservation of the footprints in an environment where they could easily have been destroyed by waves, tides, or wind.”

As with much of New Zealand, north-west Nelson was largely submerged between 70 and 20 million years ago and the footprints would have been covered by hundreds of metres of marine sediments.

However, after the country was uplifted and north-west Nelson emerged from the sea, the overlying sedimentary rock has been eroded away over the past 20 million years to expose the footprints again, thus permitting this sedimentologist and his colleagues the chance to study footprints leading into New Zealand’s ancient past.

For models and replicas of titanosaurs visit the models section of the Everything Dinosaur website: Dinosaur and Prehistoric Animal Figures.

CT scans Help Unlock Tyrannosaur Ancestry at Natural History Museum

When we are asked about the best place to find a new species of dinosaur, an answer we often give is to look more closely at fossils already in museum collections.  Often, old finds, if subjected to new research techniques can reveal some surprises.  This was exactly what happened when a beautifully preserved partial skull and jaws of a meat-eating dinosaur, originally excavated nearly 100 years ago; turned out to be a candidate for the earliest ancestor of the mighty Tyrannosaurus rex.

The fossilised remains, the oldest-known relative of the mighty tyrannosaurs discovered to date, were found in 1910, during the excavations for a new reservoir near the town of Minchinhampton in Gloucestershire.  The skull was found in rocks which form part of the Great Oolite limestone formation of the area.  These rocks were laid down in a marine environment and along with the Inferior Oolite limestone formation they make up a good proportion of the Cotswolds.  The county of Gloucestershire in south-west England is one of the most geologically diverse of all the English counties with outcrops of Cambrian, Devonian, Permian, Triassic and Jurassic aged rocks represented.

Tyrannosaur Ancestry

One of our team members was able to visit a fossiliferous outcrop earlier this year, dating from the Jurassic, Cleeve Hill.

To read the article on fossil hunting at Cleeve Hill: Fossil Hunting at Cleeve Hill.

Fossil Hunting at Cleeve Hill

The “Hideaway” at Cleeve Hill.  Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The lower portions of the skull including teeth are all the remains that have been found of this animal, but other fossils ascribed to theropods have been associated with this area.  Since this fossil was found in marine strata, it is very likely that either the animal or its carcase was washed out to sea, perhaps by a flash flood before sinking to the bottom and being quickly covered in fine sediment.

A number of terrestrial animals are known from fossils that have been discovered in marine deposits, recently the femur of a long-necked dinosaur from the Jurassic, a Cetiosauriscus was pieced together from remains found in a Gloucestershire quarry.

To read the article about the recent Cetiosauriscus find: Cetiosauriscus Leg Bone found in Gloucestershire Quarry.

Examining the Skull

The skull was believed to represent a new species of a megalosaur type dinosaur, it was named as Proceratosaurus bradleyi, shortly after its discovery.  The fossil skull was presented to the Natural History Museum in 1942 and despite representing one of the best preserved early theropod skulls in the collection, it was not studied in more detail until early in 2009 when a joint German/British team gained permission to subject the skull to CT scans to help reveal more of its internal structure.

Pictures show the fully prepared skull (the original preparation of the specimen has been augmented with more of the matrix removed to help improve the research).  The skull is placed facing to the right and the sharp, backward pointing teeth in the jaws have now been fully exposed.  The upper portion of the fossil was destroyed by an irregular fissure in the rock, so no other portions of the skull relating to this specimen have been found.

In the original 20th century paper, the dinosaur was identified as a megalosaur, known as a taxonomic waste basket, due to the amount of miscellaneous theropod remains associated with it.  The original paper commented on the crushed and flattened state of the fossilised bones, but remarked how fragile, light and delicate the skull was.

The skull seems full of holes, and to the casual observer this is seen as something of a surprise, since they imagine meat-eating dinosaurs to have huge, heavy powerful jaws and heads.  Theropod skulls were filled with air sacs, this would have helped to make them lighter.  The first hole, above the snout and completely cleared of matrix is the naris (nasal area).  A small, triangular bony projection can be seen on the top.  This is the bony core of a nose horn, this is what gave this dinosaur its name (Proceratosaurus means “first horned lizard”).

The next opening in the skull is the large antorbital fenestra, this is found behind the naris and in front of the eye socket or orbit.  The hole towards the rear of the skull behind the eye is called the laterotemporal fenestra.

The skull measures less than 30 cm long, it probably belonged to an individual no more than 3 metres long, twelve times smaller than its great descendant T. rex.

The fossil was sent to Austin, Texas where it was scanned using CT technology (computed tomography), to create X-rays and then a 3-dimensional computer image to reveal the internal structure of the fossil.  The scientists discovered that the teeth, jaws and braincase resembled those of Tyrannosaurus rex, indicating that this humble, Gloucestershire predator may be an ancestor of the giant meat-eaters that survived to the very end of the Cretaceous.

Commenting on the relationship between Proceratosaurus and T. rex, Dr Angela Milner of the Natural History Museum in London stated:

“It was quite a surprise when our analysis showed we had the oldest known relative of T. rex.”

She went on to add:

“We care for over nine million fossils here at the Museum and this discovery highlights the importance of museum collections in current and future research.  Fossils collected a century ago can now be studied again with the benefit of much greater knowledge of dinosaurs from around the world.”

To aid the scanning process some of the surrounding matrix was removed.  As a general rule, the less dense the fossil, the greater the detail that CT scanning can reveal.

Co-author of the study, which has just been published in the Zoological Journal of the Linnean Society, Dr Oliver Rauhut stated:

“This is still one of the best preserved dinosaur skulls found in Europe.  It is really surprising that it has received so little attention since its original description”.

Dr Oliver Rauhut holds dual appointments in the Department of Geological and Environmental Sciences at the Ludwig-Maximilians-Universität (LMU) in Munich and the Bavarian State Collection for Palaeontology and Geology.  He is regarded as a leading expert on the taxonomic relationships between theropods.

The use of modern techniques to study fossils found in the 19th and 20th centuries will probably lead to many more amazing discoveries, as Dr Rauhut explained:

“I’m sure that many more tyrannosaurs are still out there to be found.  I think we have just scratched the tip of the iceberg so far.”

Perhaps such new research will help to produce a more accurate cladogram of the relationships between members of the Theropoda.

To view models of dinosaurs such as Proceratosaurus and other early theropods: CollectA Age of Dinosaurs Prehistoric Life Models.

Evidence of Severe Facial Wound in Juvenile T. rex

Facial wounds discovered in the fossil specimen of a juvenile T. rex.

Palaeontologists are aware of the tough lives of tyrannosaurs as they have been able to describe and infer a number of injuries as preserved in fossilised bone.  This pathology provides an insight into the lives and behaviours of these apex predators.  Being a T. rex was certainly tough, not only did they have to contend with formidable prey animals such as the ceratopsians and hadrosaurs, but there is plenty of evidence to suggest that these predators battled it out amongst themselves.

This type of conflict when an animal from one species fights or competes with another animal of the same species is referred to as intraspecific competition.  When one considers the terrible wounds inflicted on each other by tyrannosaurs, this phrase seems somewhat inappropriate.  These fights were brutal and even juveniles got in on the act.  A new study of an immature T. rex skeleton indicates that at some time in its young life, this young Tyrannosaurus suffered a severe bite to the front of its face.

Terrible Tyrannosaurs

In a new study of the fossils of an immature Tyrannosaurus rex, part of the Burpee Museum of Natural History collection in Rockford, Illinois (United States) evidence of a brutal fight between tyrannosaurs has been found.  It seems this youngster, got into a fight and suffered a terrible bite on its face, however, since the fossil bones shows signs of healing, it looks as if this particular dinosaur lived to fight another day.

The Mounted Skull of a Tyrannosaurus rex on Display

The skull of the T. rex exhibit on display at Wollaton Hall until August 2022.  Palaeontologists have identified facial wounds in tyrannosaurs. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The Tyrannosaurus fossil in question, nicknamed Jane (although scientists are not sure whether this animal was a female), was about 11-12 years old when it died. The injury occurred sometime earlier in the animal’s life.  This bite was more than a friendly nip, the the maxilla bone (the bone at the front of the snout) and the naris (the bone that leads off the premaxilla towards the back of the skull) have been severely damaged.  Indeed, a total of four distinct puncture wounds have been identified.

Juvenile T. rex

Examination of Jane’s bones, unearthed in 2001 in Montana, (United States) showed that the wounds were almost certainly inflicted by another T. rex of about the same age.  One explanation for the bite marks on the snout that has been suggested is that may be this T. rex was grabbed by a large crocodile at a waterhole as it came down for a drink.  Crocodiles attack large animals such as antelope and zebra in Africa,  the heads of these animals are often grabbed by the crocodile as it attacks, perhaps this young T. rex was ambushed by a crocodile as it bent its head down low to gulp some water.

However, researcher Joe Peterson of North Illinois University refuted this hypothesis, stating:

“Only a few animals could have inflicted the wound.  A crocodile or an adult T. rex would have left different types of bite marks.”

For Joe Peterson and his colleagues, they believe that the oblong shaped bite marks preserved in the fossil bone indicate that the culprit was another young Tyrannosaurus.

He went on to comment:

‘When we looked at the jaw and teeth of Jane, we realised her bite would have produced a very close match to the injuries on her own face.  That leads us to believe she was attacked by a member of the same species that was about the same age.”

“The study of the bite marks on Jane’s face demonstrates that even at a young age this dinosaur was engaging in some pretty serious combat.”

Injuries in Juvenile Tyrannosaurs

Evidence of injuries in tyrannosaur fossils is not unheard of.  For example, the fossilised skeleton called “Stan”, a gracile T. rex (museum specimen number STAN-BHI3033) discovered in 1992, shows signs of having had part of the back of the head bitten off.  It seems that even this 40 foot long individual got into a fight with an even bigger T. rex.

“Stan” the Gracile T. rex also shows Evidence of Injury

Picture credit: Everything Dinosaur

The University based team believe that in the case of “Jane”, the violence may have been sparked – as it often is today among teenagers – by a territorial ‘turf’ dispute or a simple show of macho dominance.  The paper detailing the team’s study is published this month in the scientific journal Palaios.

Co-author Professor Reed Scherer, also from Northern Illinois University added:

What’s unique about this work is we learn something very, very specific about juvenile dinosaur behaviour.  This was an animal about the same size that attacked Jane.  Whether it was a sibling or from a rival group, we don’t know, but it’s fun to speculate.”

The use of sophisticated computed tomograph (CT) scans to study the bone puncture marks in detail, taken at Rockford Memorial Hospital, confirmed that the puncture marks in Jane’s jaw were consistent with injuries that had healed when the creature was alive.

A Replica of a Juvenile T. rex

A young T. rex.

Picture credit: Everything Dinosaur

Everything Dinosaur stocks a range of tyrannosaur figures including replicas of juvenile tyrannosaurs.

Visit: CollectA Prehistoric Life Figures.

Other apparent bite marks and lesions found on the skulls of adult tyrannosaurs are now believed to have been left by parasites. A paper published recently by a joint Australian and U.S. based group of scientists postulated that the lesions thought to be bite marks were actually caused by a parasite – Trichomonosis.  Jane’s scars are different and definitely caused by inflicted injury, said the Illinois researchers.

To read the article on parasites affecting tyrannosaurs: Parasitic Infection Linked to Tyrannosauridae.