New Study into the Lark Quarry Dinosaur Footprints

The Lark Quarry located near the town of Winton in Queensland (Australia) is the site of one of the most important collection of dinosaur tracks discovered to date.  When these tracks were first studied by Dr Tony Thulborn and his colleague Mary Wade and their work published in 1984, the footprints caused a sensation as the various trackways were interpreted as herd of smaller ornithopod dinosaurs in the company of some coelurosaurs stampeding after they were cornered by a lumbering giant theropod dinosaur.

Lark Quarry Dinosaur Footprints

Ichnologists (scientists who study trace fossils, especially footprints), assigned the name Wintonopus to the small, ornithopods, Skartopus to the larger coelurosaurs and the eleven prints believed to describe the large, predatory theropod attempting the ambush were assigned to Tyrannosauropus.  However, a new paper published in the academic publication “The Journal of Vertebrate Palaeontology” interprets the tracks in a very different way.

Lead author, Queensland palaeontologist Anthony Romilio presents evidence to suggest that these footprints are not evidence of a dinosaur ambush with a resulting stampede but the tracks made by dinosaurs as they forded a river.  Instead of “Walking with Dinosaurs”, this new research suggests a scenario of “Swimming or even Wading with Dinosaurs”!

Tri-dactyl Prints at the Lark Quarry Site (Queensland)

Evidence for swimming dinosaurs?

Picture credit: Dr Steve Salisbury

Upper Cretaceous Fossil Tracks

The footprints are believed to date from around 95 million years ago approximately (Albian to Cenomanian faunal stages of the Cretaceous), the strata that the footprints were discovered in does represent fluvial deposits (river sediments), however, this new interpretation proposes that the tracks were made by dinosaurs whilst in the water and not on the river bank.   Walking along a river bed, especially one where the water may have been no more than forty centimetres deep would have made sense if the banks were heavily vegetated, progress through dense scrub and forests would have been much slower if the dinosaurs had chosen a land route.

The Queensland palaeontologist stated:

“Many of the tracks are nothing more than elongated grooves, and probably formed when the claws of swimming dinosaurs scratched the river bottom.  Some of the more unusual tracks include ‘tippy-toe’ traces – this is where fully buoyed dinosaurs made deep, near vertical scratch marks with their toes as they propelled themselves through the water.”

The smaller dinosaurs, those referred to as Wintonopus may have swum, whilst the larger dinosaurs were able to wade across the water.

Swimming Ornithopods at the Lark Quarry Site

Dinosaurs going for a dip!

Picture credit: Anthony Romilio

In the paper, the scientist argues that it is difficult to see how the tracks could have been made by an animal walking or running on land, even one panicked by a ambush from a predator.  If the tracks had been made on land the impressions made would have been much flatter.

Fossilised Footprints

Fossilised footprints of a swimming dinosaur have been found in the past.  There is a very important single dinosaur trackway discovered in Spain that seems to show a tri-dactyl, theropod dinosaur touching the bottom of a lake occasionally as it swam across it.  The sediments preserve the claw marks and impressions made by the dinosaur at it touched the lake bed and pushed itself off again to continue its journey.

To read an article on the Spanish discovery: Swimming Dinosaurs.

The Lark Quarry site represents one of the most important sets of dinosaur footprints known to science.  More than 3,000 individual prints have been identified so far.  A number of the tracks, including the “dinosaur stampede/river crossing site” are on public display.

Using three-dimensional footprint mapping techniques, the University of Queensland scientist has already provided a number of new insights into the dinosaur tracks of Lark Quarry.  In 2010, Anthony Romilio published a scientific paper that suggested that the footprints assigned to the meat-eater Tyrannosauropus were actually made by a large, herbivorous ornithopod, a dinosaur similar to Muttaburrasaurus for example.

To read about the research into the Tyrannosauropus tracks: Lark Quarry Dinosaur Tracks Re-assessed.

Commenting on the newly published research and reflecting on the earlier work suggesting that the large dinosaur tracks were not made by a predator, Anthony stated that taken all together, the research suggested that the Lark Quarry sediments did not portray a dinosaur stampede.

For models and replicas of Australian prehistoric animals: Australian Dinosaurs and Prehistoric Animal Figures (CollectA).

New Study Suggests that Oviraptorids Were Show-Offs with their Tail Feathers

Over the last thirty years or so, palaeontologists have built up a large amount of data to suggest that at least some types of dinosaur were feathered.  These feathers performed different functions, for example, some dinosaurs sported coats of fine, downy feathers that would have helped to keep these animals insulated and warm.  Other types of feather arrangement, particularly longer feathers may have had a display function.

Oviraptorids were Show Offs

A new research paper, published by a scientist based at the University of Alberta (Canada), has suggested that at least one type of dinosaur, the bird-like Oviraptors had a pygostyle structure, compressed tail vertebrae that was sheathed in muscle.  This anatomical arrangement, commonly seen in modern birds would have allowed this oviraptorid to shake its tail and use any feathers on the end of it as a visual display device, perhaps to attract a mate or to intimidate a rival or even a predatory dinosaur.

Oviraptors are a group of theropod dinosaurs, distantly related to the likes of Tyrannosaurus rex and Velociraptor that are known from Upper Cretaceous strata of the Northern Hemisphere.  These dinosaurs were bipedal with small heads, as a result of their short, compact skulls.  They had beaks like birds and a collarbone to strengthen the shoulders as seen in extant birds today.

Shaking Their Tails – Oviraptorids (Ingenia spp.) Displaying

Dinosaur Courtship?

Picture credit: Sydney Mohr, University of Alberta

Oviraptor Fossils

For University of Alberta scientist Scott Persons, the opportunity to study some very fine and near-complete fossil specimens of Oviraptors that had been found in Mongolia gave him the chance to theorise on the structures of these dinosaur’s long tails.  He suggests that the tail could have ended in a fan of feathers that could have been extended and “flashed” just like a male peacocks.  He refers to these dinosaurs as being natural flirts able to flaunt their colourful feathers in extravagant displays.  They may have been able to shake their tails quite vigorously if this new research is correct.

The traditional view of cold-blooded, slow-witted, lumbering giants is gradually being replaced by a picture of very active animals with high-metabolic rates and complex social behaviours.  Using extant reptiles such as lizards and crocodiles as metaphors for the Dinosauria (Terrible Lizards), does not stack up to scientific scrutiny.

The Canadian-based scientist examined the fossils of a number of Oviraptor specimens that had been found in Mongolia.  He realised that all the dinosaurs in his study would have had long, nimble tails with attachments for strong muscles so that they could be moved back and forth.  The last caudal vertebrae of the tail (tail bones), may have been fused together to form a pygostyle, an anatomical feature seen in just one other type of animal – modern birds.

Birds more advanced than the likes of Archaeopteryx (A. lithographica), have their last five tail bones very much reduced and fused into a plate of bone, this is the pygostyle.  It seems very early on in bird evolution the long tail associated with theropod dinosaurs began to be shortened and reduced, an adaptation permitting these flying creatures to lose weight from their skeletons and to make movements in flight easier.  The pygostyle in the Oviraptors served as a support structure and anchor point for fans of tail-feathers that could have been used for display purposes.

Although no impressions of fossilised feathers are associated with the specimens Persons studied, he concludes that since feather impressions have been associated with other, earlier fossil specimens of oviraptorids, they were most likely present, just not preserved during the fossilisation process.

Oviraptor Fossil Study

The Oviraptor study is for the University of Alberta student’s Master’s thesis.  He examined the tail structure of an oviraptorid known as Khaan mckennai.  At least three specimens of this four foot long dinosaur are known, all found in the Ukhaa Tolgod region of Mongolia.  Persons noted that the tail had many vertebrae squashed together, forming a compact yet flexible structure.  Bony spines running along the tail would have provided anchor points for the attachment of large muscles.  In addition, other oviraptorid specimens showed a fused tail bone structure, the pygostyle, one example of a member of the oviraptorid group with a pygostyle is the dinosaur known as Similicaudipteryx yixianensis.

Describing his academic work, Persons went onto state:

“You stick a feather fan on the end of a highly dextrous and muscular tail and you’ve got what I think is a tail built for flaunting, that could shake a tail feather side to side, raise it up, strike a pose.  Probably to an extent that’s greater than a modern-day peacock or a turkey.”

Tail bones are easily lost when an animal dies, so the evidence for pygostyles in all Oviraptor-like dinosaurs is simply not available for scientists to study but this research raises the intriguing possibility that back in the Late Cretaceous of Mongolia there was a bunch of dinosaur show-offs, displaying and signalling to each other.

The implications of this study are that, it may be possible to identify males and females of a species if the tail bones are found.  The logic behind this idea, goes something like this; in modern birds, a number of species go through elaborate courtship displays in order to win and keep a mate.  Males of many species, Birds of Paradise, Peacocks, Black Grouse for example, possess elaborate tail fans that they use in visual courtship displays.  The caudal vertebrae (tail bones) may therefore be slightly different between males and females of the same species as these bones had to support muscles and tendons to allow the tail fans to be displayed.  Tail bones could help palaeontologists to work out which dinosaurs were boys and which were the girls.

A number of model makers have depicted Oviraptors with tail fans, an example of this is the Oviraptor from Safari Ltd, a model that was introduced a few years ago now, replacing an older version of this Asian dinosaur.

The Oviraptor Model from Safari Ltd

Part of the Carnegie Collectibles Range from Safari Ltd.

Picture credit: Everything Dinosaur

The Oviraptor model is part of the company’s Carnegie Collectibles range of scale models from Safari Ltd.

To view this range of prehistoric animal figures: Dinosaur Figures and Replicas (Safari Ltd).

The study concludes that there were sophisticated and specialised feather appendages in other dinosaur clades not just the ones that evolved into Aves (birds).

U.S. Authorities Set Out to Track Down Tarbosaurus Fossils

It may seem like a plot from Primeval or Jurassic Park but American customs officials are on the hunt for a missing dinosaur in the aftermath of a guilty plea from a Florida based, commercial fossil dealer.  Last week, Floridian Eric Prokopi pleaded guilty to falsifying importation documents and making misleading statements concerning the contents of crates of fossils imported into the United States.

Hunt for Tarbosaurus

The trail of the Tarbosaurus fossils began when an eight metre long, mounted specimen was offered for sale at Heritage Auctions in New York last May.  The exhibit fetched over $1 million USD when sold, but the lot was seized by U.S. officials as the fossils were alleged to have been illegally shipped out of Mongolia, the only place in the world where Tarbosaurus fossils have been found (Nemegt Formation).  It has been illegal for such artefacts to be shipped out of Mongolia for more than fifty years.

Tarbosaurus (Tarbosaurus bataar), was an apex predator of the Late Cretaceous.  Closely related to the more famous Tyrannosaurus rex, this dinosaur is sometimes called Tyrannosaurus bataar, indeed this is how the lot was described when first put up for auction in New York.

An Illustration of a Tarbosaurus Dinosaur

Fossils hopefully being repatriated back to Mongolia.

Picture credit: Everything Dinosaur

The image (above) is a Tarbosaurus dinosaur model from CollectA.

To view this range: Tarbosaurus Models and Theropod Figures (CollectA Age of Dinosaurs).

Last week, Eric Prokopi the seller of the Tarbosaurus fossil pleaded guilty to a number of charges referring to making false claims concerning the import of fossil material into the United States.  He is due to be sentenced in April and such charges can lead to up to seventeen years in prison however, in a plea bargain Mr Prokopi is helping the American authorities with the recovery of other fossils that may have been illegally imported into the United States.

Court Papers

Court papers reveal that one Tarbosaurus specimen, part of a set of six of these dinosaur fossils is still not accounted for, it is believed to be somewhere in Britain.  The other five specimens were in Mr Prokopi’s possession and these have been seized by U.S. officials, however, the Tarbosaurus which, according to the court documents may be in the United Kingdom, remains unaccounted for.  Sources have revealed that the plea agreement refers to “one nearly complete Tyrannosaurus bataar specimen purchased from a Mongolian individual and located in Great Britain.”

The hunt is on to see if the Tarbosaurus fossils can be found and U.S. Customs will be interested in trying to understand more about how these rare Asian dinosaur fossils came to be shipped into America in the first place.  They are keen to trace the movements of the fossils from Asia into America via the United Kingdom.  The Mongolian government is believed to be keen to unite all the known Tarbosaurus fossil material together to make an exhibit at their own dinosaur museum in Mongolia.  A request from the Mongolian government has been sent to London asking for assistance in the return of such artefacts should they be located in the Britain.

The Tarbosaurus Mounted Skeleton Offered for Sale in New York

The skeleton offered for sale at an auction in New York.

Picture credit: Reuters/Heritage Auctions

The hunt for the fossil, follows a lengthy investigation into a global trade in dinosaur bones ranging from a New York auction to southern England’s Jurassic coast.  Legal documents seen by a national newspaper suggest that a consignment of fossils was sent from the UK to Mr Prokopi in Florida.  It seems that the guilty plea may not be the end of this investigation,  American officials are keen to understand more about the logistics behind the movement of such fossils around the world.

To read about the seizure of the Tarbosaurus auction material: Seizing a Tyrannosaur.

In June 2010, the London International Art Fair had a strange item up for sale amongst the fine art and ceramics, it was the prepared skull of a Tarbosaurus.  It has been reported that this item was on sale for £125,000.  The skull came from a Dorset coast fossil dealer, British newspapers have enquired about this specimens’s whereabouts.

Scotland Yard have confirmed that its art and antiques unit had been contacted by the U.S. Department of Justice but insisted it was not currently investigating the case.

A spokeswoman commented:

“At this time no request for assistance has been made and there is no Metropolitan Police Service investigation.”

Investigations into alleged dinosaur fossil smuggling are likely to  continue with the Mongolian government seeking to have repatriated any Tarbosaurus fossil material that is found.

It is suspected that there is a substantial black market for fossil material, especially dinosaur fossils with very high prices, sometimes in excess of £500,000 being paid for rare specimens.  Fossils are smuggled out of countries and offered for sale via a network of dealers to wealthy private individuals.  Hopefully, the stiff sentence likely to be handed down to Mr Prokopi and the on-going investigation into fossil shipments from Mongolia will help deter others from such activities.