Curator Wayne Gerdtz with Jurassic poo. Image Benjamin Healley, Museum Victoria.
The lump looks small and unassuming. It has a rough texture and is surprisingly heavy for its size. This small pink and grey rock holds an intriguing secret. It is a 150 million year old sauropod dinosaur poo – fossilised and preserved as a record of life in a very different time.
Imagine standing in a lush Jurassic forest in what is present day Utah, USA.
The ground vibrates with thundering footfalls. It is a 25 tonne sauropod coming to feed. Its giant neck and small head reach into the dense vegetation to tear off some leaves. The mouthful of leaves travels down its long neck to its roomy stomach. Fermentation chambers filled with bacteria in its guts help break down the plant fibres and extract the nutrients. A soft lump of poo falls onto a bit of swampy ground, where it is preserved and fossilised – turned into stone. It is buried and remains hidden for 150 million years until someone digs it up. We acquire it for the museum.
Fossilised poo – or ‘coprolites’ – were unveiled at Melbourne Museum today in preparation for installation in the Dinosaur Walk, opening on April 3 at Melbourne Museum. A coprolite will be on open display in the new exhibition, enabling visitors to touch it for themselves.
How do we know it is dinosaur poo? It comes from a rock layer known as the Morrison formation, which is the right age and contains many fossils of Late Jurassic dinosaurs. It is the ‘right’ size and shape. It is similar to other lumps which have been analysed and have been found to have plant remains in them. The process involves looking at thin sections of the rock under a microscope, where traces of plants can be seen. We cannot be 100% sure our lump is fossilised dinosaur poo, but the evidence suggests it is highly likely.
Is it rare? Fossils of dinosaur bones are quite rare, but fossils of soft parts like skin, muscle or traces like poo are even rarer. The conditions to preserve a soft lump are unusual, so coprolites are rare.
Above: Trilobites, fossil ferns and Diprotodon - all a bit older than me. (Source: Museum Victoria)
Time is an odd sort of thing – I’m always losing it, but you can never get it back. For example, one year ago, my son wasn’t even born. Ten years ago, I was still at University. A thousand years ago, Vikings were doing their thing in
Europe . A million years ago, ancestral humans hadn’t even formed recognisable civilisations. But 600 million years? It almost goes without saying, but that’s a very long time ago. As you can probably guess, quite a bit has changed on our planet in that time.
One of the challenges we’re facing with our new exhibitions in the Science and Life Gallery redevelopment is to make this sort of timescale comprehensible – the amount of time is so big that it is hard to wrap your head around. The first of the four exhibitions to open will be Dinosaur Walk, displaying dinosaur skeletons and others, aims to summarise the last 253 million years of land vertebrate evolution, starting just before the age of the dinosaurs, passing through the Mesozoic where dinosaurs, flying and marine reptiles ruled their domains, through to their extinction and the eventual rise (and demise) of the megafauna.
So how do you fit something as mind-bogglingly vast as hundreds of millions of years into an exhibition space less than 50 metres long at
Museum ? The answers to that are, with careful selection of display objects, some very clever (and patient) exhibition designers and an equally talented exhibition team!
And consider this - if you think that 253 million years sounds like a long time, the exhibition opening 12 months after Dinosaur Walk will go back in time more than twice as far, right back to the emergence of complex life on earth, around 600 million years ago. That exhibition will also include the stories of life underwater as well as on land, and the geological processes that have shaped the very land and seas themselves. So, soon you will be able to stroll through 600 million years of life and landscapes and 253 million years of skeletons before you have a mid-morning coffee at the Melbourne Museum Cafeteria.
I think I’ll go and have one myself right now….
Fossilised dinosaur bones with comb for scale
Today I have been writing words that will be part of a new exhibition. It’s a new exhibition with an old theme – dinosaurs and other pre-historic life. According to my text there is going to be a fossil hairdresser in it. Well it isn’t actually a fossil hairdresser, that’s just what spell check came up with when I typed Hadrosaur. We have this fossil of a Hadrosaur (duck–billed dinosaur) – still embedded in a chunk of rock which came all the way from Alberta, Canada. At the museum it is affectionately called the headless hadrosaur because there is no skull fossil. It does however have imprints of dinosaur skin, and when you think of it, 70 million year old skin is pretty impressive (probably in need of a beauty therapist rather than a hairdresser).
The collection manager here at the museum is going to look closely around the fossil in the hope of finding some more skin. There are stories of similar fossils where the people preparing them (cleaning away the rock and just leaving the fossil), failed to recognise the skin imprints and destroyed them in the process of getting to the bones. I guess skin imprints are a rare thing and like a lot of palaeontology you really have to know what you are looking for, you must have a mental search pattern. There are lots of stories of things being missed and their significance only being ‘seen’ later. Fossilised embryos are a case in point...but that is another story.