Tyrannosaur Footprint Found in British Columbia

Palaeontologists and ichnologists (scientists who study trace fossils including footprints), are examining the preserved impression of a three-toed footprint made by a large dinosaur during the Late Cretaceous.  The single print measures fifty-nine centimetres long and it may have been made by a substantial tyrannosaurid.

Dinosaur Footprint

The footprint was found approximately ten kilometres from the small settlement of Tumbler Ridge.  Something like fifteen tyrannosaur footprints have been discovered to date, from locations as far apart as New Mexico, Alberta and Mongolia, but this is the ninth print to have been reported from British Columbia.  The print was found by Carina Helm, a geography student at the University of British Columbia who was out working in the area with her father.  The track was found on August 20th.

Explaining the circumstances behind the discovery, Carina explained:

“My dad and I were returning in the evening from repairing boardwalks on one of the hiking trails, when I told him I knew of some big exposed rock slabs.  We worked out that these were maybe from an age that could feature dinosaur tracks, so we decided to make a detour to have a look.”

The father and daughter team did not have to search for long to find the fossil.

The Three-Toed Dinosaur Footprint

The white line helps to show the outline of the track.

Picture credit: The Helm Family

Commenting on the Dinosaur Footprint Discovery

Looks like mobile phones have lots of uses, for example, the phone in the picture helps to show scale.

Carina added:

“The very first rock I went to, right beside the road, had this huge track-shape on it with three toes.  I thought, surely, that is too big to be a footprint?  I showed it to my dad and next thing he was on his cell-phone to Rich McCrea telling him about the find.”

The Peace Region Palaeontology Research Centre

Rich McCrea, is one of the palaeontologists at the The Peace Region Palaeontology Research Centre (P.R.P.R.C.), based in Tumbler Ridge.  This institute was founded in 2003 to help excavate, preserve and showcase the vertebrate body and trace fossils associated with this part of the Canadian Province.  Most of the footprints alleged to have come from large theropods that have been found in this region have come from remote, difficult to access locations.  In contrast, this new find was close to a road and is much more accessible.

A Likely Tyrannosaurid Track

Rich and colleague Lisa Buckley were able to confirm that this track was most likely made by a tyrannosaurid.  Although the print measures fifty-nine centimetres long, the foot that made it would actually have been bigger, the tip of the longest toe and its claw impression have been eroded away.  When asked to speculate the type of tyrannosaur that might have made this track, the P.R.P.R.C. palaeontologists have suggested that this track could  have been made by an Albertosaurus.

A Model of an Albertosaurus (Large, Late Cretaceous Tyrannosaur)

Albertosaurus (Carnegie Collectibles – Safari Ltd).

Picture credit: Everything Dinosaur

To view the range of prehistoric animals made by Safari Ltd: Safari Ltd Dinosaur Models.

Outlining how the scientists concluded that this was indeed the footprint of a tyrannosaur, Rich McCrea stated:

“It can sometimes be a challenge to identify the maker of a single print, especially one that has been weathered by the elements.  Even with the tips of the digits (the claw impressions), eroded away, the footprint found by Carina Helm still possesses characteristics that make it identifiable as the product of a meat-eating (theropod) dinosaur.  In addition to the morphological features of the footprint, which bears great similarity to the ones discovered in the Autumn of 2011 and subsequently ascribed to the ichnospecies Bellatoripes fredlundi, the size of the print and the age of the rocks it was found in provide further evidence that the track-maker was a tyrannosauroid.”

A Problem Fossil

This fossil is posing a bit of a problem for the Tumbler Ridge Museum Foundation, the organisation that established the P.R.P.R.C., the fossil is close to a road and therefore it could be vandalised or stolen.  Attempts could be made to remove the specimen, but this too, presents problems.  The slab of rock containing the print is large and transporting the fossil to Tumbler Ridge would present quite a logistical challenge.

Young Carina is proving to have quite a knack for finding trace fossils, earlier in the Summer, she was part of a team that found two other trackways preserved in much older rocks in the Tumbler Ridge area.

How Did the Ankylosaur Get Its Club Tail?

Dinosaurs as “Living Tanks”

Ankylosaurs are often described as “living tanks” these quadrupeds seemed to have taken body armour to the extremes with some specimens such as Saichania from Asia and the Late Cretaceous North American ankylosaurids Euoplocephalus and Ankylosaurus even having armoured eyelids.  They were a very diverse and widespread group of ornithischian dinosaurs, in every sense of the world.  True, ankylosaur fossils have been recorded from China, Mongolia, Canada, the United States, Australia and there have even been fragmentary bones attributed to an ankylosaur found near Folkestone (Kent, England).

In addition, these animals have very wide pelvic regions in proportion to the rest of their robust bodies.  The wide pelvis is an adaptation to accommodate a large gut.

Heavily Armoured Dinosaurs with a Long Evolutionary History

Armoured dinosaur models.

Picture credit: Everything Dinosaur

Most children can describe these herbivores, they may be very well known members of the Dinosauria, with an albeit brief appearance in the film “Jurassic World” adding to their popularity, however, a mystery surrounding the Ankylosauridae may finally have been solved.

How Did the Ankylosaur Tail Club Evolve?

By mapping the evolutionary history of these armoured dinosaurs from their Jurassic origins through to the very end of the Cretaceous the answer as to how some members of the Ankylosauridae developed that distinctive tail club may have finally been resolved.

According to research published in the academic publication “The Journal of Anatomy”, the fused tail came first and the bony club evolved later. Postdoctoral researcher Victoria Arbour (North Carolina State University and the North Carolina Museum of Natural Sciences), authored the report, a study she started when at the University of Alberta under the tutelage and guidance of renowned palaeontologist Professor Phil Currie.

Studying the Ankylosauridae Family

Victoria has spent a large part of her career studying the Ankylosauridae and she is viewed by Everything Dinosaur team members as the “go to” person when it comes to the ankylosaurids.

For example, back in October 2014, Everything Dinosaur reported on a new species assigned to the Ankylosauridae named by Victoria – Zaraapelta (Z. nomadis), fossils of which were found during an expedition to Mongolia led by Professor Currie.

To read more about Zaraapelta: Zaraapelta – In Praise of Victoria Arbour.

This new study involved examining the fossilised remains of some of the earliest known ankylosaurids, dinosaurs like the Chinese Liaoningosaurus from Yixian County, Liaoning Province (north-eastern China), as well as many Late Cretaceous forms.  An ankylosaur’s tail is composed of a handle and a bony knob.  The knob is comprised of fused osteoderms, a special kind of bone formed in the skin.  The handle is represented by the distal end of the tail (caudal vertebrae) that support the weight of the knob.

Commenting on the Study

Victoria explained:

“In order for an ankylosaur to be able to support the weight of a knob and swing it effectively, the tail needs to be stiff, like an axe handle.  For that to occur, the vertebrae along the tail had to become less flexible, otherwise the momentum generated by the knob’s weight could tear muscle or dislocate vertebrae.”

Gobisaurus – A 90-Million-Year-Old Ankylosaur

Tracing the tale of the Ankylosaurus tail.

Picture credit: Sydney Mohr

A Tale of Tails

Other ankylosaurids included in the analysis were Gobisaurus (Turonian faunal stage of the Cretaceous) and Pinacosaurus from the younger Campanian faunal stage of the Cretaceous.

Three Ways in Which the Ankylosaurid Tail Could Have Evolved

There are three ways in which the bony club and the fused, stiffened tail could have evolved:

1. Bony club first – early ankylosaurids would show evidence of osteoderms forming and enveloping the end of the tail
2. Handle first – primitive members of this family would have overlapping or fused tail bones
3. The club and handle could have evolved simultaneously, if this was the case, then Early Cretaceous ankylosaurids would show both anatomical features, perhaps with tails getting stronger and tail clubs getting heavier over time

How Did the Ankylosaurs Get their Unusual Tails?

Three different theories of ankylosaurid tail evolution.

Picture credit: Journal of Anatomy

Comparative Analysis

The comparative analysis revealed that by the Early Cretaceous, ankylosaurids had begun to develop stiff tails with fused caudal vertebrae.  The bony knob feature did not appear in the fossil record until the Late Cretaceous.

Dr Arbour concluded:

“While it’s possible that some of the species could still have developed the handle and knob in tandem,” it seems most likely that the tail stiffened prior to the growth of the osteoderm knob, in order to maximise the tail’s effectiveness as a weapon.”

The upshot of this conclusion is that ankylosaurs used their tails as defensive weapons first and then only later did the heavy club on the tail evolve.   Commenting on this work a spokesperson from Everything Dinosaur stated:

“This is a fascinating study, one can speculate that the bony club tail evolved in response to the emergence of bigger and more dangerous theropod predators such as the tyrannosaurids that could be regarded as the apex terrestrial predators in the Northern Hemisphere towards the end of the Mesozoic.”

The Tail Bones of Ankylosaurs

Caudal anatomy of ankylosaurs.

Picture credit: Journal of Anatomy

Tail Clubs

The picture above shows (A) an oblique dorsal view of the tail club of Dyoplosaurus acutosquameus from Canada, the fossils of which are around 76 million years old (Campanian).  This is typical of the derived Ankylosaurine tail  with a fused tail and a bony club.  Gobisaurus (G. domoculus) line drawing is (B) a left lateral view of this earlier ankylosaurid’s tail showing fusing of the bones.

Picture (C) shows the same fossil specimen as (B), but this time viewed from the other side, the deep groove running along the bottom is the haemal canal.  X-ray (D) and the interpretive drawing (E) are from an ankylosaur tail from Alberta, the last tail bone is small and rounded when compared to the long distal caudal bones.  Picture (F) shows two tail bones from Mymoorapelta maysi, a basal member of the Ankylosauria known from the Late Jurassic of the United States.

Typical of Nodosaurids and Basal Ankylosaurs

This anatomy is typical of nodosaurids and other basal ankylosaurs, the prezygapophyses (forward projecting points of bone located on the neural arch of the vertebrae), overlap the adjacent vertebrae by about 25% of the centrum (the main part of the vertebra situated below the neural arch).  In contrast, picture (G) shows the fossilised remains of Liaoningosaurus (L. paradoxus) which dates from the Aptian faunal stage making the fossil some 120 million years old.  The boxed area in (G) is highlighted and magnified (H).  In Liaoningosaurus the prezygopophyses overlap the preceding vertebra by at least 50% including a much more fused and stiffened tail, more typical of later ankylosaurids.

Ankylosaur Tail Club

 This research has provided new evidence to help scientists understand the evolution of ankylosaurid tails.  Fossils from China such as those of Liaoningosaurus suggest that the mechanism to support a tail club may have evolved at least forty million years before it was taken to extremes by the Late Cretaceous ankylosaurs such as Euoplocephalus and Pinacosaurus.  Early ankylosaurids evolved the handle first, those distal ossified osteoderms came later.

For models and replicas of armoured dinosaurs and other prehistoric creatures: PNSO Age of Dinosaurs.

How Good is the Fossil Record of the Dinosaurs

With something like 1,200 different genera of dinosaur now described, our knowledge of the Dinosauria has increased a great deal, especially over the last twenty years or so.  Many different types of dinosaur have been discovered and we at Everything Dinosaur try to keep a database using this blog.  For example, since the beginning of July, we have written articles about a newly discovered, very bird-like oviraptorid from southern China (Huanansaurus ganzhouensis), North America’s latest ceratopsian discovery (Wendiceratops), the new dromaeosaurid from Liaoning Province (Zhenyuanlong suni) and most recently, the basal sauropod Pulanesaura from South Africa.

How Good is the Dinosaur Fossil Record?

Just over the weekend, we reported on a giant horned dinosaur skull from South Dakota that might well turn out to be a new species of ceratopsian, albeit, one that would be very closely related to Triceratops.

However, will palaeontologists ever be able to create a definitive list of all the dinosaurs?  What percentage of the Dinosauria will ever be known?  Scientists at Bristol University have set about trying to find out by assessing just how good the fossil record for the dinosaurs actually is.

So Many Different Types of Dinosaurs Described

So many different types of dinosaur.

Picture credit: Everything Dinosaur

Trying to Calculate How Good the Dinosaur Fossil Record Is

Professor Mike Benton of the University of Bristol, set out to assess how good the fossil record is for the Dinosauria and for early tetrapods in a bid to answer the question as to whether the fossil record adequately represents the patterns of diversity of animals through time.  A number of other authors have attempted to assess the quality of the fossil record and in this new study, published in the journal “Palaeontology”, the journal of the Palaeontological Association, Professor Benton set out to plot how the knowledge of dinosaurs has been accumulated since the first scientific description (Megalosaurus) back in 1824.

The research does not provide a definitive answer with regards to how representative the vertebrate fossil record actually is, but this study does suggest caution needs to be taken when using some popular methods to try and remove bias from the known fossil record of the Dinosauria as well as the other Tetrapods included in the analysis.

Plotting the Number of New Species Named Against the Number of Newly Discovered Fossil Bearing Formations

Number of species against number of new fossil bearing formations.

Graph credit: Bristol University

Professor Benton Comments

Professor Benton explained:

“In the past ten years, many palaeontologists have tried to find the true pattern of evolution by using measures of sampling to estimate where the fossil record is well known or poorly known.  But it turns out that many of the popular methods are not doing what they are supposed to.”

The Bristol-based palaeontologist plotted the history of research into the Dinosauria from 1820 to the present day.  He logged the number of new species described and how the patterns of discovery match the patterns of discovery of new geological formations.  He noted that the patterns of discovery are closely linked, one or two new dinosaurs for each fossil-bearing geological formation that is newly explored.

More Fossil Bearing Geological Formations Discovered = More Dinosaurs Described

If there is a significant link between the number of dinosaurs described and the number of new geological formations discovered then how does this connection work?  This link can be explained in two ways:

1. Rock formation discoveries drives dinosaur fossil finds
2. Dinosaur fossil finds drives the discovery of new fossil-bearing formations

The usual view is that (1) is correct, that rocks drive fossil finds.  Palaeontologists are keen to find new dinosaur species, but the new species could only be found if they explored new rock formations around the world.  It could be argued that our ability to discover new types of dinosaurs (or any fossil group for that matter) is dependent on the availability of suitable rock formations to explore.

Plotting the Link between Early Tetrapod Discoveries and Rock Formations

Early tetrapod discoveries 1820-2015.

Graph credit: Bristol University

The graph above shows the same relationship in early tetrapod fossil discoveries from 1820 to the present day, but if there is a causal relationship between fossil finds and formations then how does this relationship work?

Fossil Record

The opposite view is that fossil discoveries drives the search for new rock formations.  Palaeontologists set out to look for new dinosaurs in a very focused and disciplined way.  When new dinosaurs are found they would often add a new dinosaur-bearing formation to the known list.  In this case, the limiting factor is not simply the availability of suitable rock formations to explore because scientists do not search systematically but they go straight to areas when they hear there are bones to be excavated.

Professor Benton added:

“I have been worried for a while that some of the popular correction methods actually make things worse.  By removing the numerical signal of the formations, localities or collections they were actually removing a huge amount of real information, and producing a resulting curve that is meaningless.  The fossil record is clearly incomplete, and it is clearly biased by many factors, but many of the supposedly “corrected” diversity curves we have seen recently may actually be further from the truth than the raw data.”

A New Analysis

This new analysis does not provide us with a definitive answer as to the diversity of the Dinosauria, or indeed, for any other fossil group of vertebrates.  However, we can infer from what we already have discovered that there are very probably a lot of weird and wonderful dinosaurs yet to be found.  It is not possible to state that we, after 195 years of research (1820 to 2015), have identified 10%, 50% or even 1% of all the types of dinosaurs that have ever existed, such statements by their very nature are likely to be invalid.

This new research does provide a clearer picture of why there is such a close correlation between dinosaur species numbers with formations, localities or collections.  The numbers of all four are connected because they are all telling much the same story, they are measuring the same history of life on Earth and our knowledge.  Professor Benton concludes that it is not possible to isolate one or other of these measures and then try to use it as an independent yardstick for sampling.

New Dinosaurs Will Be Discovered

There is one certainty, well, it’s almost a certainty.  New types of dinosaur will be discovered in the future and if the graph developed by Professor Benton is anything to go by, a lot of new dinosaurs (at least compared to the historical data), will be discovered in the next few years and Everything Dinosaur will do its best to blog about them.

For models and replicas of dinosaurs and prehistoric animals: Prehistoric Animals and Dinosaur Figures.

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

Revising Lizard Evolution in Gondwana

The Squamata (lizards and snakes), might be the most diverse and specious of all the extant reptiles but their evolutionary history remains a mystery.  The preservation potential of these reptiles can vary dependent on the characteristics of the ancient ecosystems which they inhabited.  In addition, the small size of many of the early species of lizard and snake makes finding fossilised bones and other clues as to the history of this Order all the more difficult.

However, a team of scientists including Tiago R. Simões (Dept of Biological Science, University of Alberta), have published a paper in the journal “Nature Communications” that sheds light on the evolution of the iguanas and their near relatives.

Studying the Iguanians

The family of extant reptiles known as the iguanians (iguanas and agamids) are one of the most diverse and widespread type of lizard today.  However, like other types of lizard, their evolutionary origins are uncertain.  There are two main divisions within this family, firstly there is a sub-group called the acrodonts, these lizards have no root or socket to their teeth and the teeth are attached to the top of the jaw bones.  In the other sub-group, the pleurodonts they do not have roots on their teeth either, but instead the teeth attach to the inside portion of the jaw.

Acrodont iguanians are confined to the Old World, while pleurodont iguanians are found only in the Americas.  A newly described fossil however, breaks this pattern.  The international team of scientists have published a paper on a Late Cretaceous acrodont iguanian, the oldest known New World acrodont iguanian.

An Illustration of the First New World Acrodont Iguanian – G. sulamericana

The fossils date from around 80 million years ago.

Picture credit: Julius Csotonyi

Gueragama sulamericana

The fossils, including the holotype material, a partial lower jaw come from the Goio-Erê Formation, exposed near Cruzeiro do Oeste, in Paraná State, southern Brazil.  Fossils found in this locality represent an arid, very dry environment dominated by pterosaurs and large dinosaurs.  However, scurrying around the hot, desert-like environment was a short, rather stubby lizard.  It has been named Gueragama sulamericana, which translates from the local dialect and Portuguese as “ancient agama from South America”.

The discovery of these fossils of an ancient, New World acrodont means that in the distant past, lizards with the acrodont dentition had a worldwide distribution and were very probably widespread across the ancient landmass of Gondwana.

The Holotype Jaw Fossil (Various Views)

An ancient toothy lizard.

Picture credit: Universidade do Contestado, Santa Catarina, Brazil.

Scale bar in the picture = 2 mm.

Fossil Discovery Raises Questions

A number of questions have been raised with this discovery, for example, if only the pleurodont iguanians are found in the New World today, then what happened to the acrodonts that once lived in this part of the world too?

Lead author of the scientific paper, Tiago R. Simões stated:

“It becomes clear acrodontan iguanians migrated throughout the southern continents much earlier than previously thought (actually reaching regions where they do not inhabit today) by the order of tens of millions of years.”

This new research extends the fossil diversity of Late Cretaceous Brazil and suggests that the arid deserts of this part of the world may have supported a greater range of lizards than previously thought.  The scientists hope to find more lizard fossils, including material representing Gueragama so that they will be better able to understand the evolution and radiation of the stem acrodontans.

As for the date given to the G. sulamericana fossil material, we at Everything Dinosaur estimate these fossils to be more than 80 million years of age.  The strata which makes up this part of the Goio-Erê Formation is believed to date from the Turonian to the early Campanian faunal stages of the Late Cretaceous (90-80 million years ago, approximately).

Late Cretaceous South America

South America in the Late Cretaceous

Picture credit: Nature Communications

Fossil Finds in South America

Between the Aptian/Albian faunal stages and the Campanian faunal stage of the Cretaceous, sphenodontians were thought to be the dominate animals filling the iguanian niche.  Sphenodontian fossils have been found in northern Patagonia, in the provinces of Chubut (Tres Cerros), Río Negro (Los Alamitos, Cerro Tortuga, Cerro Bonaparte and La Buitrera) and Neuquén (El Chocón), these discoveries are represented by black circles on the map above.

Lizards were present in the state of Ceará in north-eastern Brazil (Araripe Basin), as well as in the south-eastern/southern states of Minas Gerais (Peirópolis), São Paulo (Marília and Presidente Prudente) and Paraná (Cruzeiro do Oeste), and in the province of Río Negro (Cinco Saltos and La Buitrera), Argentina, represented by yellow stars on the map. The red star indicates the type locality of G. sulamericana in southern Brazil.

Recently, Everything Dinosaur reported on another Brazilian Squamata fossil discovery.  Spotted by chance on a tour of a German museum, scientists have identified the first example of a four-footed snake, an animal believed to be a transitional creature between limbed lizards and true snakes.

To read this article: Fossil Snake with Four Limbs Described.

Horned Dinosaur Skull Found in South Dakota Might Be New Species

The small town in Buffalo in the north-west of South Dakota was so named as back in the 19th century vast herds of buffalo (American bison), roamed across this part of the world.  However, another type of horned animal has got local townsfolk excited, one that would have dwarfed even the largest of today’s hoofed giants, a very-well preserved partial skull and jaws of a huge horned dinosaur which might turn out to be a new species.

Acquired from a Fossil Collector

Fossil collector and dealer Alan Detrich purchased the dinosaur skull found in Harding County from another fossil collector John Carter back in 2012, but it has taken more than two and a half years to prepare the specimen ready for sale.  When the fossil skull and lower jaw were first excavated it was thought that the bones represented a very large specimen of Triceratops (T. horridus).  However, with the fossil completely exposed, Alan along with Neal Larson (Larson Paleontology Ltd) who was tasked with preparing the fossil, believe that this could be a brand new species of horned dinosaur.

Over the last fifteen years or so, a number of new North American horned dinosaurs have been named and described, however, if proved to represent a new species, this dinosaur skull could be heralded as one of the most spectacular dinosaur discoveries of all, the nasal horn alone measures nearly forty-five centimetres long and the skull itself is over 1.82 metres in length.

Ceratopsian Skull

Commenting on the unusually large nasal horn, Alan Detrich stated:

“They are [Triceratops nose horns] usually half that size and the skull is eight feet long, which would be a monster skull for a Triceratops.”

Neal Larson, the founder of Larson Paleontology Unlimited and a co-founder of the Black Hills Institute of Geological Research with his brother Pete Larson, who coincidently is also working on a centrosaurine specimen at the moment, was given the task of trying to prepare the specimen.  It took over 1,000 pain-staking hours to carefully excavate the fossil from its iron siderite matrix.  The preparation work was extremely difficult, as despite the robust nature of the fossil bones, the matrix with its iron component (iron carbonate) was extremely hard.

A Ceratopsian Exhibit at a Museum (Triceratops)

A cast of a Triceratops skeleton on display at the Naturmuseum Senckenberg (Natural History Museum – Frankfurt). On the left a wall mounted example of a Plateosaurus can be seen.  Is the Buffalo skull a new species?

Picture credit: Everything Dinosaur

For articulated models of ceratopsians and other dinosaurs: Beasts of the Mesozoic Articulated Dinosaur Models.

A Large Centrosaurine Skull

A spokesperson from Everything Dinosaur exclaimed:

“It’s only when you see a person stood next to the beautifully preserved skull that you can really appreciate just how big the animal actually was.  This is certainly one of the largest centrosaurine skulls that we have seen.”

For Neal, who holds a degree in geology and has been excavating fossils for some forty years now, the ceratopsian skull represented a tough challenge given the hardness of the surrounding matrix.

He stated:

“I immediately had my suspicions this was something new because of the size and placement of the nasal horn.  They’re usually in the middle of the nose, not the front and it’s twice as large as most of them.  On top of that, the frill at the top of the skull curves upward. They usually lay back.”

Ceratopsian Skull Could Represent a New Species

The skull has a strange ridge under the jaw, something that is not seen in Triceratops skull material.  Mr Detrich is now trying to find a museum to house this specimen, preferably in the United States, potential buyers for this huge dinosaur skull are currently being contacted.

The Ceratopsians of North American seem to have evolved into a very diverse range of forms during the Late Cretaceous.  Some of the skulls of these herbivorous dinosaurs were truly immense.  As a clade, the ceratopsians are considered to have the largest skulls in proportion to the rest of their bodies of any known vertebrate.  A few years ago, Everything Dinosaur reported on the discovery of another enormous horned dinosaur skull, this time from Alberta, Canada, a dinosaur that was believed to be an ancestor of Triceratops.

To read about this fossil discovery: Enormous Skull of Eotriceratops Discovered.