Insight into the Late Cretaceous Arctic – Not the place for a Swim

A joint Canadian, Polish and US team of scientists have braved Arctic conditions to research and report upon a 70 million-year-old ecosystem uncovered in the Arctic Circle.  Freshly excavated and mapped fossil bearing sediments in the Canadian province of Nunavut in the far north of Canada have provided an unique insight into the fauna of a Late Cretaceous sea.  A number of new animals have been discovered plus a large amount of plesiosaur material, ancient shark teeth, fossil sponges and even some prehistoric poo (coprolite).

First discovered by geologists surveying the northern tip of Devon island in the 1980s the sediments remained unexplored until the joint Polish, Canadian and American team set out to study this area in more detail.  Their research has revealed that during the Late Cretaceous this area was much warmer than today and supported a rich ecosystem of marine life.

The paper detailing the team’s research has just been published in the Proceedings of the British-based Royal Society.  Approximately 73 million years ago (Campanian faunal stage), this area was covered with a shallow, semi-tropical sea that supported a variety of strange and exotic creatures, including the long-necked, fish eating plesiosaurs.  On the shore there were large conifer forests which would have thrived in the short Arctic summers, with perhaps migrating herds of duck-billed dinosaurs visiting the region to take advantage of the long daylight hours in the spring and summer months.

The Late Cretaceous Arctic

The prehistoric world uncovered by the palaeontologists contrasts with the bleak conditions to be found on Devon Island today.  It is uninhabited (in fact it is probably the largest area of land on Earth not to be permanently inhabited by people).  A few birds are indigenous to the area, and some hardy musk ox scrape out a meagre living grazing on the lower slopes of the island’s uplands.

One of the more exciting finds are the thick bones and armour-like scales of an unidentified type of fish, estimated to have grown to approximately 2 metres in length and a new species of sponge, preserved in three-dimensional perfection. The sponge, Nunavutospongia irregulara, is named for the Canadian territory where it was found and was the subject of a separate paper published earlier in the Canadian Journal of Earth Sciences.

All of the specimens are being held on behalf of the Nunavut government by the Canadian Museum of Nature in Ottawa, where palaeontologist Stephen Cumbaa, a co-author of the study along with other scientists is continuing the research.

Cumbaa said the “mystery fish,” which isn’t likely to have been a major predator, “doesn’t look like anything else that’s been described. We’re still trying to piece it together enough to decide what we’ve got.”

The largest animals living in the area at the time seem to have been the Elasmosauridae (long-necked plesiosaurs).  These fish-eating marine reptiles reached lengths in excess of 15 metres.  As a group they went extinct at the end of the Cretaceous.

An Illustration of a Typical Elasmosaur

Picture credit: Mike Fredericks

To see a model of plesiosaur and other marine reptiles: Marine Reptiles and Prehistoric Animal Models.

Devon Island is also important to geologists and palaeontologists for a number of reasons.  Firstly, it contains a number of important mineral resources and secondly, as it is the site of a remarkably well preserved meteorite impact crater (called the Haughton impact crater).  A large extraterrestrial body crashed into the island approximately 39 million years ago.  During this period the area was still relatively warm compared with today and there were forests covering the island.  However, the cold climate of this region today has helped preserved the impact crater in pristine condition, permitting scientists to study the effect of such impacts in great detail.

The knowledge gained about meteorite impacts in the cold conditions of Devon Island have helped NASA scientists predict the likely conditions to be encountered when probes visit the planet Mars.

Trackway that shows Footprints of Three Types of Dinosaur Discovered

The town of Sparwood lies in the Elk Valley, one of the most rugged and beautiful areas of British Columbia.  It is famous for wildlife and its natural beauty, now some ancient residents of this particular area of Canada are grabbing the headlines.

Dinosaur Footprints

Local coal miners exposed a near vertical slab of rock that contains the trackways of at least three different types of dinosaur.  News of this find reached local palaeontologist, Rich McCrea, the curator of the Peace Region Palaeontology Centre at nearby Tumbler Ridge, who was despatched to investigate.  The strata in which the footprints were found have been dated to approximately 135 million years ago (Hauterivian faunal stage).  Fossils of dinosaurs in Lower Cretaceous strata in North America are relatively rare, compared to Upper Cretaceous finds.

The footprints are of a big theropod (meat-eating dinosaur), most likely to be a member of the Allosauridae.  Some of these large three-toed prints are a metre long, indicating an animal the size of an Allosaurus fragilis, perhaps 12 metres long or more.  The second set of prints are the typical more rounded prints of a large sauropod (long-necked dinosaur).  These prints are quite size-able and indicate and animal that could have weighed as much as 40 tonnes.  The third set of smaller dinosaur prints have yet to be identified.

Jurassic Highway

Commenting on the importance of this discovery, McCrea said: “we’ve been waiting for this kind of find,” . “It was a long time coming.”

Footprints and trackways are known as trace fossils.  They preserve evidence of the activity of animals.  They have a major advantage over other types of fossils such as bones and teeth (body fossils).  Unlike body fossils, in which the body may be transported a long way after death, far away from the area where the animal or plant actually lived, most trace fossils are direct, in situ evidence of the environment, time and place where the animal lived.

A Large Theropod Footprint (Hell Creek Formation USA)

Potential tyrannosaurid Print.

Picture credit: Dr Phil Manning (Manchester University)

The picture above shows the discovery of a single theropod footprint in Upper Cretaceous sediment.  The dinosaur that made the print has yet to be formerly identified but this could be the footprint of a Tyrannosaurus.

To read more about the finding of a possible tyrannosaur footprint: Possible T. rex Footprint Found.

Trackways of a large theropod in situ with a sauropod such as these uncovered in B.C. have never before been found in Canada, although McCrea has found sauropod tracks in the same region in 2000.  Evidence of big carnivore such as an Allosaurus has been found in the province as well as in neighbouring Alberta, but this trackway discovery is still very significant for palaeontologists.

Trackways can tell researchers much more about a dinosaur than the finding of a single, isolated bone.  “When you compare it to finding a single bone … finding a trackway is like finding a whole skeleton,” McCrea added.

“You get far more information from it.  You can learn about herding behaviour, predator-prey interactions. We get to do a little more on the biological end of things like bio-mechanics … how they walked around.”

McCrea and his assistant plan to spend a fortnight at the site, and will make a latex mould of the footprints to take back to Tumbler Ridge. They will also take three-dimensional photos of the footprints and map the trackways, but they will not actually be removing them, as to remove them may damage these valuable items, evidence that dinosaurs walked around British Columbia 135 million years ago.

For dinosaur models and figures including tyrannosaurs: PNSO Age of Dinosaurs Figures and Models.

Notes on Hypsilophodon – one of the most studied of all Dinosaurs

With the recent new research into the intercostal plates on Hypsilophodon being published we thought it an appropriate time to produce a brief article on Hypsilophodon a small, bipedal ornithopod whose importance to palaeontologists is often overlooked.

At least two species of Hypsilophodon are known, the best known and the one with the most fossil material is Hypsilophodon foxii, however, a second species of Hypsilophodon – H. wielandi has been identified from an isolated femur (thigh bone) found in the USA, but this identification and interpretation has been disputed by a number of scientists as the fossil is indeterminate.

The first remains of any hypsilophodontid to be discovered were found in the a slab of sandstone from the coast of the Isle of Wight in 1849.  The remains, which consisted of a partial skeleton were first thought to be of a young Iguanodon, an animal that had been described in 1825 and whose fossils had been found in the same strata.  By 1868 several near complete skeletons had been recovered from the same area by the amateur naturalist the Reverend William Fox.

This new material displayed several characteristics not known in Iguanodontids and it was proposed that these fossils plus the one found in 1849 did in fact represent a new species of Iguanodon.  This dinosaur was named Iguanodon foxii in honour of the Reverend’s work.

Another renowned English scientist, Thomas Henry Huxley noted that these “miniature iguanodontids” had many differences between them and other known Iguanodon species.  One notable difference was the teeth which were narrower and more sharply pointed than Iguanodon teeth.  This prompted Huxley to rename this dinosaur in 1896. He called it Hypsilophodon foxii.  The name means “high ridge tooth” in recognition of one of its most distinguishing features.  The name is pronounced – hip-sih-low-foh-don.

In 1882, James W Hulke published a paper in the highly influential scientific journal – “The Quarterly Proceedings of the Geological Society”.  He concluded that this little dinosaur was adapted for climbing over rocks and living in trees because of its long fingers and toes plus it could use its tail as a counterbalance, a bit like a modern tree-kangaroo.

A number of other anatomical features were described including the fact that Huxley believed that the first digit of the foot was reversed like a bird’s hallux claw.  This would have helped Hypsilophodon to perch on branches.  We now know this was an inaccurate interpretation and Hypsilophodon was a fleet-footed and most definitely terrestrial dinosaur.

Hypsilophodon – a Dinosaur Model Set?

CollectA Hypsilophodon family group.

To view the CollectA model range: CollectA Prehistoric Life Models.

So much Hypsilophodontidae material has been recovered from one particular area of the Isle of Wight that the strata has been named the Hypsilophodon bed, it is unusual to find so many vertebrates preserved together in one place, the specimens show little sign of attack by scavengers and it has been suggested that these animals represent part of a herd that became trapped and perished in some inter-tidal quicksand.

Article on new Hypsilophodon research: New Insight into Hypsilophodon.

New Study Suggests Hypsilophodon was built for Speed

Today at the Beijing Olympics, attention turns to the beautiful National stadium affectionately called the Birds Nest Stadium as the track and field events get underway.  The heats for the 100 metres will be taking place, who will be the fastest runner on the planet?  Few commentators and pundits expect the British athletes to be amongst the medals for this particular event.  However, a new study by scientists, shows that one ancient resident of Great Britain could have given the top sprinters a run for their money.

Hypsilophodon

Although it would have stood only waist-high next to an Olympic sprinter, the small British ornithopod Hypsilophodon foxii had a fair turn of speed, and new research suggests it even may have possessed a special adaptation that prevented its ribs from rattling during its speedy runs.

This new paper, published in the scientific journal Cretaceous research helps shed light on a mystery surrounding this small, agile dinosaur.  A number of mineralised plates have been found in association with Hypsilophodon fossils.  It had been speculated that these were scutes, pieces of dermal armour that were embedded in the skin of this lightweight dinosaur.  However, such armour would have only provided limited protection from fierce meat-eating carnivores such as Neovenator and other members of the Allosauridae.  More importantly, the heavy armour would have slowed this animal down and seemed to contrast with other anatomical adaptations seen in the numerous fossil skeletons of this dinosaur that indicate a fast running animal.

These thin mineralised plates, once believed to be pieces of body armour may actually have been robust cartilage tissues that may have supported the ribs and helped regulate breathing, especially as Hypsilophodon exerted a lot of energy, running for example.

“Hypsilophodon had elongated legs and a stiffened counterbalancing tail that suggest it was almost certainly a fast runner” commented Richard Butler one of the co-authors of the study.  Richard, a member of the palaeontological team at London’s Natural History Museum added; “the plates might have functioned to support the ribcage during fast running”.

Hypsilophodon remains are relatively common in Lower Cretaceous strata of both Europe and America.  The Hypsilophodonts were a highly successful group and a number of superbly preserved fossil specimens are known.  This animal was named and described in 1869.  At the time of its formal classification, British Zoologist Thomas Huxley commented that with its five-fingered hands and light body this dinosaur could have lived in trees.  A number of illustrations were made of this arboreal dinosaur and depictions of Hypsilophodon sitting comfortably on a conifer branch can be found in many old dinosaur text books from the 1970s and 1980s.

A Small Model of the Dinosaur Called Hypsilophodon

CollectA Hypsilophodon family group.

The model (above) is part of the: CollectA Prehistoric Life Model Range.

Previous descriptions of Hypsilophodon fossils describe these little plates as components of dermal armour, perhaps a double row of plates running down the spine.  Now Butler and his associates have a different explanation for the finding of these items with fossils of this particular dinosaur.  The team noted that the plates were weakly constructed and overlaid but were not actually fused to the ribs.  Butler explained the previous interpretations by saying:  “that as the body of the dead Hypsilophodon individual rotted and collapsed…the bones from the skin came to be closely associated with the internal bones.”

“Our careful reexamination of the specimens shows, however, that the bony plates are always closely associated with the outside surface of the ribs from the front end of the ribcage and are certainly not armour,” he added.

The Natural History Museum scientists believe the plates were similar to the bony structures referred to as “uncinate processes,” seen in the rib-cages of many modern birds.  Although it is not clear whether dinosaurs had the same breathing systems as birds.  Since this feature is involved in bird ribcage support, facilitating movement and breathing, the scientists now suspect the structures played a similar role in the dinosaur.

Diagrams show part of the scapula and ribs of a Hypsilophodon specimen from the London Natural History Museum, the scapula (shoulder blade is labelled “scap”, ribs are labelled as are the mineralised plates “pl”.  They do seem to be closely associated with the rib bones and not likely to be dermal armour that has fallen into the skeleton as the animal’s flesh decomposed.  Perhaps they are intercostal plates helping to regulate breathing during arduous exercise.

The British team have suggested that because evidence for similar mineralised plates has been detected in other dinosaur skeletons, the researchers further theorise that all small-bodied, bird-footed dinosaurs possessed these structures.

Darren Naish, of the University of Portsmouth’s School of Earth & Environmental Sciences, is also intrigued by the fact that the structures could be “widespread, possibly even universal” in other small, herbivorous dinosaurs.

Naish added, “People have mostly forgotten about these ‘armour plates’ in recent decades, but this new work shows that a fresh look at old specimens can still reveal new information on even the best known of dinosaurs”.

Giant Prehistoric Kangaroos and other Beasts wiped out by First Australians

The debate over the impact of human migration as humans encounter indigenous species has been fuelled once more with the publication of a new paper speculating on the demise of the mega-fauna that once lived on the island of Tasmania.

The research, carried out by a joint Australian and British team, has been published in the prestigious American scientific journal – Proceedings of the National Academy of Sciences.  The research team have concluded it was the impact of human settlement and hunting that led to the extinction of many of the large animals on Tasmania, not climate change as had been previously argued.

Australian Mega-Fauna

It was the chance discovery of the remains of a giant prehistoric kangaroo that proved to be the catalyst for the study.  The researchers postulate that it was the human settlers who hunted to death this slow breeding animal and other very large mammals that lived on Tasmania at the time.

For a long time the fauna and flora of Tasmania had been isolated from the rest of Australia but as sea levels fell a land bridge formed between this island and mainland Australia, permitting people to settle in this area.  The arrival of such a proficient and capable predator such as man, would have had a major impact on the local ecosystem.

Human Involvement?

The debate regarding the significance of human settlement on the island’s mega-fauna centres on the skull of a giant kangaroo found in a cave in the thick rain-forest of the rugged northwest of Tasmania eight years ago.

Scientists dated the find at 41,000 years old, some 2,000 years after humans first began to live in the area.

“Up until now, people thought that the Tasmanian mega-fauna had actually gone extinct before people arrived on the island,” a member of the British and Australian study, Professor Richard Roberts, commented.

Professor Roberts and his team, considering the date of the skull, had concluded that it was likely that hunting not climate change and resulted in so many extinctions.  Large animals that perished around this time included the giant kangaroo, a wombat (another marsupial), the size of a cow and the fierce marsupial lions that were the top predators on the island prior to the arrival of man.

A Marsupial Lion

An articulated skeleton of a marsupial lion is shown in the picture, the animal is facing to the right and the strong, powerful skull can be seen in the top of the picture.  Note the huge front limbs, used to hold and overpower their prey.  The marsupial lion or Thylacoleo was perhaps the largest mammalian predator of the Australian Pleistocene, it terrorised Australia until extinction approximately 40,000 years ago.

Tasmania may have been one of the last places that a size-able population of these carnivores existed – although some people believe that marsupial lions still exist.  There have been a number of mysterious sightings and reports of large, four-footed animals across Australia, could the Thylacoleo still exist?

Discussing the potential influence of climate change on the Tasmanian ecosystem of 40,000 years ago, Professor Roberts, stated that the idea relating sudden climate change to the extinction of many of the large animals was disputed by the fact the area had a very stable climate over this critical time period.

“Things were very climatically stable in that part of Australia and yet the mega-fauna still managed to go extinct,” the Professor pointed out. “So it’s down to humans of one sort or another.”

Slow Reproduction

Roberts said because the large animals were slow to reproduce it would not have required an aggressive campaign to see them quickly die out, however, frequent predation over a sustained period would eventually put pressure on a species to survive.  The large herbivores of Tasmanian would have not encountered humans before and would not have had any natural defences or instinctive responses towards them.

Animals rapidly declining in the face of a new threat is quite common amongst isolated, island populations.  The Dodo for example, was wiped out in just a few years following the first human visitors to the island, there was some hunting, but rodents and dogs that arrived with the settlers were perhaps the main cause of this huge bird’s demise.

“A lot of people still have in their minds an axe-wielding, spear-wielding people, bloodthirsty, out there slaughtering all over the place — it wasn’t like that at all,” Professor Roberts said.

“It was basically just one joey (baby kangaroo) in the pot for Christmas. And that’s all you’ve got to go to do to drive slow-breeding species to extinction.”

Roberts said the Tasmanian results back up the theory that man was responsible for the death of the mega-fauna on mainland Australia, estimated by some to have occurred shortly after human occupation about 46,000 years ago.

The Mass Extinction of Giant Animals

The reasons behind the mass extinction of giant animals, which took place around the world towards the end of the last ice age, has been hotly contested with theories ranging from climate change to human and extraterrestrial impacts.

The finding of the latest study has already been contested, with Judith Field of the University of Sydney saying the idea that humans killed the giant creatures was “in the realms of speculative fantasy”.

“Humans cannot even be placed at the scene,” she told the Sydney Morning Herald.

It is likely that the debate over the impact of human arrival and settlement on other species will continue.  H. sapiens in various parts of the world and at various times, may have had a significant impact on habitats and ecosystems.

Whether it is the debate over the effect of Clovis man in North America, or the influence of the Cro-Magnons over European fauna, scientists will continue to theorise over the actual significance of a human population over the rest of the ecosystem.  Certainly, there is no doubt that today, humans are having an enormous impact on the planet’s other inhabitants.

At 6.7 billion we are the most common large mammal on Earth and our exploitation of resources and demands for food and living space are having a serious impact on virtually ever other species.  Indeed, some scientists have claimed that this is the period of the “sixth great mass extinction” of the Phanerozoic (visible life), with an estimated 50 species a day becoming extinct.

To view models of extinct animals: Prehistoric Animal Models.