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Live from the dig- Day 1

May 6, 2015 by

The best times that you can hope for at work are those days when you don’t have to actually go to work! And that’s what happened to me today. Only a few weeks in the planning, my crew and I left this morning for a fossil dig at an awesome Pliocene (3.5 million year old) fossil site near Chinchilla on the Darling Downs, around three hours drive west of Brisbane.

Euryzygoma tooth

A 3.5 million year old tooth from the weird wombat-like marsupial, Euryzygoma

Our goal of the trip: to have a scout around the area, keeping an eye out for fossils of the ancestors of our modern vertebrate faunas. We were joined on our trip by our dear friend, Joanne Wilkinson from the Queensland Museum, an awesome bunch of Grade 10 kids from the Samford Valley Steiner School, and my interstate colleague, Dr Julien Louys from the Australian National University in Canberra.

The Samford crew are undertaking a super-important mapping project in the area, plotting in all of the major fossil layers from which bones have been collected from over the past 30-odd years. My crew consists of Dr Tara Clark, PhD student Kyle Ferguson, and Honours student Nick Wiggins. Both Kyle and Nick have been on only a few fossil digs, so it’s a great opportunity for both of them to get their hands dirty and a bit of field experience under the belt. Julien works on a wide range of projects across Australia and Southeast Asia, and is particularly keen in extending his primary research into the Pliocene history of our continent.

Euryzgoma tooth

Another Euryzgoma tooth, this time a lower incisor

We left really early, making it out to the site by around mid-morning. Our first day was spent inducting the students around the fossil site, and collecting the odd bit of fossil bone here and there. Our best discoveries of the day include fossil bones of giant and weird wombat-like marsupials like the enigmatic Euryzygoma, fossils of giant grey kangaroos (Macropus pan) – the ancestors of the modern roos – plus a massive range of fossil crocodile bits and pieces. Taken together, we can see that diversity around the area was markedly different in the past. The weird marsupials are totally extinct today, and the crocs are now found only in tropical parts of Australia.

We are going to be tweeting live from the dig during the course of the trip. Some of our discoveries are featured below. If you’re on Twitter and would like to learn more, you can follow our trip with the hashtag #LiveFromTheDig. We’ll also do our best to post daily blog updates here on our progress.

 

 

 

 

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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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Excavating the owl’s dinner plate

May 9, 2012 by

Undergraduate student volunteer Nick Wiggins (UQ) excavating at Colosseum Chamber

Recently I wrote about an ongoing study at Colosseum Chamber, an extensive fossil deposit located at the Capricorn Caves tourist park, just north of Rockhampton in central eastern Queensland. The chamber occurs within an ancient cavernous limestone, which itself dates back to the Devonian (over 350 million years ago). The Colosseum deposit is around 2 m deep and, to put it simply, is chockfull of the fossilised remains of an ancient feast. The bones are the leftovers – the undigested parts – from the feeding activities of owls over the past several thousand years. The fossils consist of a huge number of teeth, jaws, and post-cranial skeletal elements from a range of small-bodied species such as frogs, skinks, bandicoots, dunnarts, antechinuses, planigales, possums, and rodents.

Having first identified the deposit back in the mid-2000’s, we were lucky enough to obtain some recent research funding from the Ian Potter Foundation, The University of Queensland and Australian Research Council to continue our excavations. In mid-April, we ventured out for a new fieldtrip to the site.

Lower jaw of brushtail possum from the Colosseum Chamber fossil deposit

The trip was led by Dr Julien Louys from UQ with me as second-in-charge, and we were joined by other colleagues from UQ, the Queensland Museum, and volunteers including PhD student Jonathan Cramb (QUT) and undergraduate student Nick Wiggins (UQ). Although these were the folk who did most of the digging, the trip just would not have been possible without the generous support of the Capricorn Caves tourist park who put us up and allowed access to the cave, and local cavers, Noel and Jeanette Sands who also assisted with the excavations (Noel also cooked up an awesome barbie for my last night in town!).

From our preliminary dating study, we know that the deposit accumulated over the last 80 thousand years. This is a particularly exciting time period to be investigating. The last 80 thousand years included an episode of great climatic upheaval, numerous species extinctions, and was also the time that saw humans first set foot on the continent. The goal of our work is to use the Colosseum Chamber

Maxilla of southern brown bandicoot from Colosseum Chamber. The species is extinct from the region today.

fossil record to explore how the local faunas reacted to such prehistoric events. Having a robust understanding of species response(s) to past environmental perturbations is absolutely fundamental in informing modern conservationists and climate scientists about the possible effects of climate change on living populations.

Previously we had excavated the deposit to a depth of around 90 cm from the modern cave floor. This year we were able to extend the dig much deeper, to almost 2 metres deep. The digging got quite difficult the further down we got- both logistically (it’s not particularly comfortable working in such a cramped environment with other sweaty, smelly palaeontologists!), and because we hit a lot of large chunks of limestone, signalling that we were getting close to the bottom of the deposit.

Lower jaw of an extinct rabbit rat, recently discovered by PhD student Jonathan Cramb

Thousands of kilograms of sediment were removed from the cave in buckets and were taken down to the bottom of the ridge for sieving. Digging is fun, but the sieving is where you get to see all the amazing fossils that the deposit contains. Jonathan, our resident rodent expert, recently discovered a new fossil species of Rabbit Rat from Colosseum Chamber (named Conilurus capricornensis– the species name is in honour of the Capricorn Caves tourist park), and was extremely excited to see a whole heap more of his unusual rodent emerge from the sieving!

During the trip we were able to collect new samples for dating including charcoal (radiocarbon dating), straw stalactites (uranium-series dating) and sediment (optically stimulated luminescence dating). Getting those samples dated is now the next major job, not to mention the huge amount of bones that need to be taxonomically identified and sorted into skeletal groups. No doubt we have a mammoth task in front of us, but the information that we can potentially extract from the deposit is just so critical and important for modern conservation that we just can’t ignore it. Updates to come!

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