Research website of Dr Gilbert Price

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Keeping your hands clean in the field

May 1, 2013 by
Euryzygoma premaxilla fossil from Chinchilla showing three incisor teeth

Euryzygoma premaxilla fossil from Chinchilla showing three incisor teeth

The life of a palaeontologist isn’t all that glamorous. Most of my time is spent in the office in front of a computer writing reports and grant proposals. One of the things that I really look forward to is getting out in the field and getting my hands dirty. There is nothing quite like being outside in the fresh air and digging up fossils.

I recently ventured out to Chinchilla, southeast Queensland, in search of Pliocene megafauna. I’ve written previously about Chinchilla’s fossil record; in a nutshell, the fossil faunas date to around 3.5 million years and include all the ancient ancestors of the animals of the Quaternary (the time period that we are currently in). Significant amongst the Chinchilla fossil species is a mega-marsupial, the wombat-like Euryzygoma. Not only was it the biggest marsupial of its time, but it probably ranks as number 2 or 3 of all time! Euryzygoma is a real special guy- not only is it the direct ancestor of the Pleistocene Diprotodon, but it is unique in that it is one of the only mammals known on the entire planet that had a skull that it is wider than it is long! This is made possible by it possessing these incredible cheek flanges that are directed outwardly perpendicular to the rest of the skull.

Students protecting the Euryzygoma fossil with wet newspaper

Students protecting the Euryzygoma fossil with wet newspaper

During our time in Chinchilla, I stumbled across a pretty interesting looking Euryzygoma specimen eroding from an ancient river channel. The fossil, although broken, included the front part of the premaxilla (‘snout’) and contained three incisor teeth. It’s definitely a specimen that will contribute significantly to understanding more about how Euryzygoma operated in life.

We were lucky to have several guests join us during our trip- grade 10 students from the Samford Valley Steiner School. They were worked alongside us, not so much on the palaeontology side of things, but were focussed on surveying the region and drafting topographic maps. The maps will be just so important and will allow us to plot in exactly where the fossils come from.

Students cutting up the hessian in anticipation for plastering the fossil

Students cutting up the hessian in anticipation for plastering the fossil

Even though this is one of my favourite bits of doing fieldwork, I spoke to my other colleagues on the trip and we all agreed that it would be a great chance for the students to get their hands dirty and help excavate the new fossil… and they did a tremendous job! Because it is such a delicate specimen, it was necessary that we just didn’t dig the fossil out and throw it in a bag, but rather, we needed to plaster the fossil in a similar way as if you broke your leg. The first step was to dig around the fossil, making sure that we knew where the extremities of the specimen were (only a little part of it was actually exposed), and to ensure that there was enough area for the plastering work. The students then soaked sheets of newspaper and wrapped them around the fossil. There are a couple of reasons for doing this- firstly it will cushion the specimen once the jacket is finally removed; and secondly, it protects the specimen from the plaster (plaster is notoriously sticky stuff and could actually wreck the specimen if it is applied to it directly).

Steiner School students plastering the Euryzygoma fossil

Steiner School students plastering the Euryzygoma fossil

While some of the students did this part, others busily cut up strips of hessian and mixed the plaster. Then it was time to get messy! The students soaked the hessian strips in the plaster and then wrapped them around the specimen. The idea is that the hessian reinforces the plaster much like steel reinforces concrete. When the plaster eventually dried, we had a super strong cast around the specimen. We left it for a few hours to harden and then we dug under it, rolled it over, and it was ready to go. Because the students undertook the entire task, I didn’t have to get my hands dirty at all! I think that they got a lot out of it- I mean, it’s not every day that one gets to make a plaster jacket for a fossil of an extinct mega-marsupial!

The specimen travelled back with us to The University of Queensland and is now ready for additional preparation work. Although, I was thinking about it the other day- this might be another great opportunity for kids to do the prep job at an upcoming Open Day at UQ. At this rate, I might not have to clean out dirt from under my fingernails ever again!

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Diprotodon’s big day out

November 8, 2012 by
The early stages of preparing the Diprotodon skull (photo: I. Sobbe)

The early stages of preparing the Diprotodon skull (photo: I. Sobbe)

I recently wrote about a giant Diprotodon skull that was discovered fossilised in Pleistocene-aged deposits on the Darling Downs. It is a monstrous skull, measuring around 90 cm in length, and discovered by a local simply walking along the creek. With the help of the discoverer, we excavated the skull, then my friend, Ian Sobbe, a local farmer and amateur palaeontologist, set to work preparing the skull.

Ian spent the best part of a year working on the specimen. Simply put, Ian did a cracking job. It’s a wonderfully preserved skull with exquisite detail. Ian used a combination of brushes, dental picks, scrapers, glues and other consolidants to remove the surrounding sediments and ensure that the skull wouldn’t crack and break as it dried out.

The Diprotodon skull nearly finished (photo: I. Sobbe)

The Diprotodon skull nearly finished (photo: I. Sobbe)

With the original discoverer’s blessing, the skull was donated to the Queensland Museum in September 2012. By having the skull in an institution like the Queensland Museum, it ensures that the specimen will be well-looked after and stored in the most appropriate conditions (temperature and humidity controlled storage and so on) to ensure its long-term preservation. The skull will most likely also go on display to the public sometime in the next year or so.

Ian and I have some big plans for the skull. We’d like to eventually write-up a description of the specimen and have it published in a peer-reviewed science journal. We are also working with a PhD student from Monash University, Alana Sharp, who is conducting a study on the nasals of the big guy.

Ian Sobbe and the Diprotodon

Ian Sobbe and the Diprotodon

I have also drilled tiny tooth samples from the skull that will allow me to directly date it using uranium-series methods (currently in preparation). I already have some radiocarbon dates for the skull, and hopefully soon, some optically-stimulated luminescence (OSL) dates by my colleague, Dr Kathryn Fitzsimmons (Max Planck Institute for Evolutionary Anthropology, in Germany). If we can get some really good results- dating, anatomy and biology, it’ll be just so important for learning more about how Diprotodon lived and died.

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Digging up Diprotodon

August 1, 2012 by

It was around August 2011 that my friend, Ian Sobbe, received a phone call from a local on the Darling Downs: “I’ve found a skull in the dirt- it looks like a Grand Angus bull”, the caller said. Well, Ian, being not only a local farmer from the Downs but also an amateur fossil collector, started to get excited. Knowing a lot about the fossils from the region, Ian checked out the photos that the local had emailed him and immediately called me up. The skull was not a Grand Angus at all, but as Ian correctly identified, it belong to the extinct mega-marsupial, Diprotodon.

The Diprotodon skull was found eroding out of this creek bank

The Diprotodon skull was found eroding out of this creek bank

Diprotodon was a giant among giants- not only the largest marsupial that lived on the Darling Downs during the Pleistocene, but is also the largest marsupial that ever lived… at any time… anywhere on the entire planet! Resembling an oversized long-legged wombat, Diprotodon was truly the king of Ice Age Australia. The cause of its extinction around 40 thousand years ago is heavily debated. The leading hypotheses developed to explain its extinction are centred around climate change associated with the last glacial cycle, or human impacts (such as through overhunting). The debate is one of the most polarised in Australian palaeo-sciences. The difficulty in determining the cause of the extinction of Diprotodon and other megafauna, is in part, due to a lack of reliable data with which to test the leading extinction hypotheses- especially well-dated fossil records. But here, Ian and I saw a great opportunity to travel out to the new fossil site, not only to excavate the new specimen, but to collect some samples critical for dating.

The Diprotodon is over 90cm long!

The Diprotodon is over 90cm long!

Ian and I met with the discoverer and travelled down to the creek where the skull was found eroding out of an ancient deposit. Our jaws dropped when we saw it- it was a monster, measuring around 90 cm in length! With the help of the discoverer, we excavated the skull. During the day, I spent a bit of time documenting the geology of the area, as well as collecting some sediments for optically-stimulated luminescence (OSL) dating. There was also a little bit of charcoal buried in amongst the skull- I also collected it with the plan to date it using radiocarbon methods.

The plaster jacket containing the skull weighed around 170 kg!

The plaster jacket containing the skull weighed around 170 kg!

 

We put a plaster jacket around the skull to protect it, but it was just so enormous that the three of us were not able to carry it. We were able to lift it with some difficulty- Ian and the local on the back-end, me on the front, but we just couldn’t move it out of the deposit- we sunk right down into the mud and couldn’t move. We ended up going back to the vehicles and drove around the neighbourhood looking for help. We came across some electrical tradies and asked them for assistance- thankfully they said ‘yes’! It took five of us to get the skull up out of the gully, carried across the field, and lifted into the back of Ian’s ute. We estimated that the plaster jacket, with the skull and surrounding sediment, weighed around 170 kg!

Ian is currently in the process of preparing the skull. It’s starting to look pretty good too- one of the best preserved skulls that has ever been discovered, not only on the Darling Downs, but across the entire continent. I’ll be sure to post some pics of the skull when it is finally cleaned up!

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