A Dinosaur in the Cupboard Under the Stairs

Thanks to a dedicated geologist and the careful conservation of his materials and notes a sixty-six-year-old mystery about dinosaur footprints on a cave ceiling in Queensland (Australia), has been solved.  Palaeontologist Dr Anthony Romilio (University of Queensland), was able to decipher and interpret a series of dinosaur trackways preserved in Lower Jurassic strata, now exposed on a cave ceiling with the help of notes, photographs and casts of the prints stored in a cupboard under the stairs of a house in Sydney.

Dinosaur Footprints on the Ceiling

The Dinosaur Tracks from the Cave Ceiling (Insert Shows Estimated Size of Track Makers)

Picture credit: Historical Biology

Dr Romilio, of the School of Chemistry and Molecular Sciences  (University of Queensland) explained:

“The town of Mount Morgan near Rockhampton has hundreds of fossil footprints and has the highest dinosaur track diversity for the entire eastern half of Australia.  Earlier examinations of the ceiling footprints suggested some very curious dinosaur behaviour; that a carnivorous theropod walked on all four legs.”

There have been hundreds of dinosaur tracks reported from the so-called “fireclay caverns” in Mount Morgan.  Five prints first described by Ross Staines, the geologist who made such careful notes (1954), purportedly represent a theropod dinosaur that had left a handprint (manus), the interpretation was that this theropod had been walking on all fours.  Most theropods are characterised by their obligate bipedal stance.  Dr Romilio set out to determine whether this particular track did indeed preserve this very untypical theropod dinosaur behaviour.  Unfortunately, it was not possible to access the trace fossils “in situ”, the caverns have been closed since 2011 due to concerns about public safety.

A Line Drawing Showing the Five Tracks Studied

Picture credit: Historical Biology

Unable to view the fossils in the cave, it would have been difficult to determine what the tracks represented.

A Stroke of Good Fortune

However, Dr Romilio had a chance meeting with local dentist Dr Roslyn Dick, whose geologist father found many dinosaur fossils over the years.

Ms Dick commented:

“I’m sure Anthony didn’t believe me until I mentioned my father’s name – Ross Staines.  Our father was a geologist and reported on the Mount Morgan caves containing the dinosaur tracks in 1954.  Besides his published account, he had high-resolution photographs and detailed notebooks, and my sisters and I had kept it all.  We even have his dinosaur footprint plaster cast stored under my sister’s Harry Potter cupboard in Sydney.”

A Digitally Reconstructed Dinosaur Track Created from the Archive Material Compiled by Ross Staines

Picture Credit: Dr Romilio (University of Queensland)

Extensive Notes and Meticulous Records

The extensive information archived by Ross Staines and carefully stored by Ms Dick and her sisters Heather Skinner and Janice Millar, permitted Dr Romilio to conduct a thorough analysis of the trace fossils.  He was able to digitise the original analogue photographs and to make a virtual, computer-generated model of the dinosaur track that had been stored under the stairs.  As a result, it was concluded that the five tracks were all foot (pes) impressions and that no handprint was present.

It turns out that these tracks do not represent the prints of a single dinosaur, but actually two dinosaurs produced the five tracks, one slightly smaller than the other, which led to the misinterpretation of one of the footprints as being the preserved impression of a dinosaur hand.  The splayed toes and moderately long middle digit of the footprints permitted the researcher to determine that these were probably not the footprints of a theropod, but that the tracks represent the progress of a pair of ornithopods.

Dr Romilio commented:

“Rather than one dinosaur walking on four legs, it seems as though we got two dinosaurs for the price of one – both plant-eaters that walked bipedally along the shore of an ancient lake.”

Dinosaur Footprints Mystery Solved

Thanks to the careful conservation of their father’s work, this is one Australian dinosaur trackway mystery that has been solved.  These tracks do not represent a theropod dinosaur walking in an uncharacteristic quadrupedal gait, as Dr Romilio explained:

“You don’t assume T. rex used its arms to walk, and we didn’t expect one of its earlier predatory relatives of 200 million years ago did either.”

The contribution of the ladies has been recognised, they are all cited as co-authors/contributors to the scientific paper.  We are sure their father would have been very proud.

A Life Reconstruction of the Larger of the Two Ornithopod Dinosaurs Believed to Have Made the Tracks

Picture credit: Dr Anthony Romilio

Dinosaurs Walking on the Ceiling?

How did the trace fossil end up on the ceiling of a cave?  The dinosaurs were not defying gravity, the explanation is very straight-forward.  The dinosaurs were walking on the soft sediment associated with a lake around 195 million years ago (Sinemurian faunal stage of the Lower Jurassic), the impressions they made in the soft sediments were infilled with sand.  Over time, the softer mudstone and shales were eroded away to expose the imprints as natural casts.

A Photograph of Ross Staines Measuring the Dinosaur Tracks

Picture credit: University of Queensland

Everything Dinosaur acknowledges the assistance of a media release from the University of Queensland in the compilation of this article.

The scientific paper: “Archival data provides insights into the ambiguous track-maker gait from the Lower Jurassic (Sinemurian) Razorback beds, Queensland, Australia: evidence of theropod quadrupedalism?” by Anthony Romilio, Roslyn Dick, Heather Skinner and Janice Millar published in the journal Historical Biology.

Visit the Everything Dinosaur website: Everything Dinosaur.

CT Scans Reveal the Armour of Aetosaurs

A student from Bristol University has carried out a study into the armour on the tail of an aetosaur.   The study, published in the Scottish Journal of Geology, has provided fresh information on how these large, lumbering herbivores kept themselves safe from ancient predators.  Emily Keeble, a recent graduate from the palaeobiology programme at Bristol University carried out the study under the supervision of Professor Mike Benton (School of Earth Sciences).  CT (computerised tomography), scans were undertaken, the first time this scientific method has been employed to better understand how the armour of an aetosaur functioned.

A Model of a Typical Aetosaur.

Picture credit: Everything Dinosaur

The picture (above) depicts an aetosaur figure (Desmatosuchus haploceras) from Safari Ltd.

To view the range of Safari Ltd prehistoric animal figures: Safari Ltd. Wild Safari Prehistoric World Models.

Late Triassic Archosaurs

Aetosaurs were heavily armoured, herbivorous archosaurs that were geographically widespread during the Middle and Late Triassic.  The term “aetosaur” is from the Greek and it means “eagle lizard”, when scientists first examined the skulls of these animals, their superficial resemblance to the skulls of eagles was remarked upon.  The fossil specimens used in this research were collected from a sandstone quarry near the town of Elgin in north-eastern Scotland.  They had been donated to the nearby Elgin Museum, where staff members Janet Trythall and Alison Wright were able to identify what they were and arrange for the scanning in Bristol.

Professor Benton explained:

“Aetosaurs were first identified from an Elgin specimen in 1844, but at that time people thought they had found a giant fish.  The first specimen showed a number of rectangular scales, arranged in a closely overlapping, regular pattern, and it was called Stagonolepis, meaning drop-shaped scale.”

Dorsal and Lateral Views of the Scottish Aetosaur Stagonolepis

Picture credit: Bristol University (illustration by Jeffrey Martz after work by Alick Walker)

CT Scans Provide Details on Aetosaur Osteoderm Structure

The fossilised tail bones were subjected to high resolution CT scans, this permitted the researchers to see surface details and the texture of the bones and related armour plates.

Emily Keeble added:

“What had been identified as giant fish scales are actually armour plates, or osteoderms, made of plates of bone and embedded in the skin, just like in modern crocodiles.”

Two specimens were studied, both associated with caudal vertebra and possibly from the same animal, but they do not fit together.  Each fossil shows a complete circle of osteoderms around the tail, two above, two on each side, and two below.

Caudal Specimen of Stagonolepis robertsoni Used in the Fossil Study

Picture credit: Bristol University

Regular Rows of Osteoderms

The researchers discovered that the rows of osteoderms were very regular and in life covered the entire body from the back of the small head, over the neck, down the back and along the tail.  Osteoderms also covered the flanks and underneath.  There were even small osteoderms over the fleshy parts of the arms and legs.

The Second Stagonolepis robertsoni Fossil Specimen Used in the Research

Picture credit: Bristol University

Aetosaur Armour Makes an Effective Defence Against Predators

This study suggests that the armour of these herbivores wrapped around them completely and would have made an effective defence against predators such as rauisuchians and ornithosuchids.

Emily Keeble added:

“Vertebrae of the tail are preserved inside the ring of osteoderms, and these show the specimens were only slightly squished during the preservation process.  We could also see how the osteoderms overlap like roof tiles, the osteoderm in front slightly overlapping the one behind.  They were linked with connective tissue so the armour overall was flexible, but tough and could probably protect the animal from the fierce predators of its day.”

A Colourised Image of Aetosaur Osteoderms and a Single Scale Shown in More Detail

Picture credit: Emily Keeble (Bristol University)

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

The scientific paper: “Three-dimensional tomographic study of dermal armour from the tail of the Triassic aetosaur Stagonolepis robertsoni” by E. Keeble and M. Benton published in the Scottish Journal of Geology.

The Everything Dinosaur website: Everything Dinosaur.