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.  A new study has got to grips with the noses of dinosaurs.

The Noses of Dinosaurs

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.

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.”

Examining the Nasal Passages

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 Stegoceras validum is mapped.

Picture credit: Ohio University/The Anatomical Record

Studying Stegoceras

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.”

Endothermic Implications?

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).

For models and figures of dinosaurs and other prehistoric creatures: CollectA Prehistoric Life Models and Figures.

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.

Giant Kangaroos

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.

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

Extinction Theories

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.

Extinct Sthenurines

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.

One Massive Toe

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.

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.

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.

Cave Paintings

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.

Symbolic Explosion

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.

Faded Artwork

The artwork is very faded in the photographs, so we have circled in green the rock art in the images 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.

Visit Everything Dinosaur’s award-winning website: Visit Everything Dinosaur.

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).

The Ankylosauridae

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”.

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).

Discovered in 2011

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.

Ziapelta sanjuanensis

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.

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.”

Closely Related to Canadian Ankylosaurids

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.

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.”

Unusual Features

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.

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.”

Specialising in Studying Ankylosaurs

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.