Discover what goes on beyond our exhibition floors and past the security doors with our series of 24 podcast episodes.
What does it take to be a palaeontologist? Join Dr Espen Knutsen, Senior Curator of Palaeontology for episode 13 of the Museum Revealed podcast as he outlines the process of preparing a plesiosaur fossil from the field to the lab and the new digital technologies that allow palaeontologists to look beyond the bones.
Dr Espen Knutsen is Senior Curator Palaeontology at the Queensland Museum Network, based at the Museum of Tropical Queensland campus in Townsville. His position is co-appointed with the College of Science and Engineering at James Cook University. Originally from Norway, Espen completed his PhD at the University of Oslo in 2012.He is a vertebrate palaeontologist and over the past 12 years has conducted pioneering fieldwork and excavations in Australia, the Arctic, the Netherlands and the USA . He has described five new species of Jurassic marine reptiles, and was part of an international multidisciplinary research team studying a newly discovered Jurassic marine ecosystem from the high-arctic archipelago of Svalbard, Norway.
Sea Monsters: Prehistoric Ocean Predators opens at Queensland Museum on 20 November 2020. Learn more about Dr Espen Knutsen’s research and the ancient marine reptiles that ruled the depths of the oceans in this new exhibition.
RB: Welcome to the Museum Revealed podcast brought to you by the Queensland Museum Network. Join me, Dr. Rob Bell (RB) as we chat to people that make museums so fascinating, from curators to scientists and researchers, we dive deep into conversations with these storytellers. They inspire us to be curious about our past, make sense of the present and help us consider the future. We’re joined now from the Museum of Tropical Queensland, Dr Espen Knutsen (EK), who’s going tell us all about palaeontology and specifically, I’m interested in obviously, you go out looking for fossils. I think every small child knows what a palaeontologist does, but tell me, how much time do you spend out looking for fossils? And I suppose we want to follow the journey of that fossil. Let’s start with how much time, in a year do you spend out in the field looking for the fossils?
EK: Not enough, unfortunately. I would prefer to spend the year out there, but here in northern Queensland particularly, there’s only certain times of the year that are really conducive for doing this sort of work. You can’t really go out in the wet season because you risk getting stuck out there and not being able to come home. So mainly focused around the May, June, July, August, September period, we go out for as long as we can. Normally, it’s a couple of weeks at a time and we go to different localities. So it’s scouted in advance, so I look at maps, some Google Earth or whatever, and we might go collecting fossils that we found previously or we might just go out and search for new fossils.
RB: So you’d use technology like Google Earth to scout new fields?
EK: Yeah, it certainly revolutionised the way we can work, because I actually see what the ground is or sort of see what the ground is going to look like before we go to the place. It’s hard to tell from the top of the map whether it’s going be vegetation cover or whether it’s going to be scree covered with scree on soil or something like that. What we really want, is a fresh rock outcrop that we can find fossils sticking out of the rock, staring at someone in the face sort of thing. And that would give the best sort of preservation that we could get.
RB: All right. So let’s say you’re out there. You’ve found the first little bit of fossil poking up from the rock. What happens next?
EK: What we are likely to do then is what we call a little test dig. Because what might happen is that what we see might just be so the tail end of the fossil and everything else is eroded away hundreds or thousands of years earlier. And it’s gone, long gone. Or it might be just the start of the fossil and the rest is sort of still going into the side of the hill. The rest is all there. So what we want to do is quickly sort of take off a little bit of the top layer above the fossil and carefully brush our way down and just sort of see what the fossil does as it goes into the hill. If it can give us any clues of whether it was likely to contain more or if it’s the last bits of the fossil sitting in the rock. So we want to do that before we commit to making a much larger excavation, which would be doing after that taking off a whole heap of more rock and expanding the quarry, depending on the size of the fossil. If you’re talking like a marine reptile, plesiosaur, they are about five metres long, you might need a five metre long hole or maybe three, four metres wide. And depending on the slope of the hill as well, we might be removing anywhere from two to five, six metres of rock on top of it as well.
RB: Wow. So with those sort of quantities I always pictured a palaeontologist with a tiny hammer and a paint brush, but you must at times have fairly industrial equipment out there.
EK: Sometimes if you’re lucky, you can get industrial equipment in there like tractors or pumps and loaders you might be able to get in. I’ve never been on any of those sorts of excavations. I’ve always been in the places where you can’t get anything in and everything has to be done by hand. So you end up moving several tonnes of rock, by hand. What happens while you’re out there all the time it takes to dig these things out. And also, what we always like is once we’ve extracted the fossil, is to fill in the hole up as well. So there’s minimal scarring in the environment of what we’ve done.
RB: So when you are extracting the fossil, that obviously sounds like it’s fairly time consuming in itself. It’s coming out usually encased in some sort of rock?
EK: Yes. Well, especially for these marine animals that I normally work on. They are often preserved in shale, which is the fossilised, if you want, lithified mud, which was the ocean floor back in the day and not cutting what we call mudstone or shale, which is a fine grained sort of rock often dark grey or black and can be quite flaky which makes it easier to prepare the fossil afterwards and also easier to dig in because you don’t need to cut the rock with the rocks or anything like that to get things out. You can just sort of use a shovel and a pick and trench around or excavate the area that you’re interested in. Definitely. It’s all consuming, but very dependent on the rock type you find the fossil in.
RB: So you’d have to take then, the pieces so for example, you have, as you said, a complete plesiosaur fossil or mostly complete. You’re taking it out in sections. And do you keep those sections together? Essentially, you’re removing a giant jigsaw puzzle encased in shale or some sort of rock. What’s the process like with that?
EK: There are two main categories of vertebrate fossil so there are those that are disarticulate or disarticulated which are the ones where all the bones have been sort of jumbled up compared to what they were like in life and life position. And then you have the articulated ones where it looks like the skeleton of the animal has died and all the soft tissues are gone, but the bones are exactly where they were originally. So disarticulated one, sometimes it’s easier to just collect the individual bones or areas containing a lot of bone. But if you have articulated ones, particularly if you have a five-metre long animal, then you can’t encase that whole thing in one plaster jacket and transport it because that would weigh tonnes. So what we do is a bit of spinal surgery sometimes, and we remove a couple of the vertebrae in sections the way we would like to cut the animal in the sections that we record, everything precisely where it came from and label everything. So when we get back in the lab and everything’s prepared, we can nicely reinsert these parts of the spine or whatever that we might have removed to split the skeleton. You don’t really want the jackets to be much more than about one square metre because suddenly it becomes unmanageable to handle.
RB: So, yeah, you mentioned a plaster jacket. So what exactly does that involve? Is that a way of sort of keeping it all together until you get it back to the preparation?
EK: Yeah, that’s right. So these fossils are normally quite fragile. So you can’t just put them on a shovel or grab them out of the rock and chuck them in the back of the ute and off you go. You’ve got to carefully excavate from the top. So you get the extent of the animal as it is preserved. And then, you know, decide where you want to sort of cut it up and make plaster jackets. And plaster jackets consist firstly a layer of what I like to use wet toilet paper, because it’s supports the bone really nicely. So it’s really a layer between the fossil and the plaster and put on top, because if you just start putting plaster on top, you’ll never see the fossil again. You’ll just never get it out of that plaster. And then you’ve got a whole other job. So you’ll have a layer and some people like to use aluminium foil or newspapers. I personally prefer toilet paper, wet toilet paper and so dab on with a wet paintbrush. Then you put wet hessian soaked in plaster over the top there and build up a layer of plaster about a few centimetres thick depending on the size of the jacket. Also encase the rock and the fossil inside it so it is a safe cocoon so you can transport back to the museum. All you need to do is a top layer first and then you’ve got to somehow do the underside. And to do that, you’ve got a trench around the whole fossil and plaster the sides of the rock until you sort of keep on fencing around it, until you’re left with almost like a mushroom shaped thing with plaster on the top, you can flip it over to the other side and you cut away the excess plaster that you put on. So dig your way down to the fossil from the underside as well. And then you put another layer of toilet paper, plaster and hessian on the other side so that you have the fully cocooned fossil that’s ready to be transported.
RB: I can already tell what there’s going to be a lot of time and effort just getting that one jacket ready and on the back of the ute to transport. So let’s say you’ve got now the whole plesiosaur and its various parts, in its jackets in the back of the ute. All of that goes to somewhere in the end, I suppose. Get the fossils out of the jacket and out of the rock.
EK: That’s right. So then it goes to the museum and the lab there, we’ve got to get a saw to cut open the plaster jacket to reveal the fossil inside. And then someone, maybe myself or a volunteer or a student will sit there for a few months and sort of peck away at this rock to remove all the rock away from around the fossil. And as you go along, what you want to do is stabilise the fossil so you sort of dig your way down because all this rock is sort of supported nicely hugging the fossil, so it doesn’t fall apart. You are removing the rock so that fossil might break apart or collapse. What you want to do is have some sort of adhesive across the fossil to stabilise it so that that doesn’t happen. As you go along and sort of keep adding to it, the adhesive is very important. It has to be reversible. So you can’t just soak it in super glue because if you make a mistake, as you know, with superglue, it can be pretty hard to get back out again. So we have this special adhesive. So you can add ethanol or alcohol and you can redo it again if you need to.
RB: So then that sounds like quite a painstaking job in itself. You end up with all of the parts of, let’s say, the plesiosaur. Is it simply a matter of, I suppose, putting it back together and working out how it should have looked?
EK: Yes. So let’s say we haven’t articulated one in the field and we have to split it up, then already all the bones would be in the position that they were in life. There’s no guesswork needed because everything was recorded. So you can just put everything back together the way it was. If you had a disarticulated specimen where all the bones so jumbled up in a pile, it can make it tricky. So there’s certain things you can look at. For instance, in the spine, all the vertebrae from the neck look different from the ones in the torso and are different from the bones in the tail. The front and rear flippers look different. And that sort of thing. And obviously the ribs look different as well. So you can sort of guesstimate where they’re supposed to be in the body and you get an idea of which parts are preserved and which parts they belong to in the body that way. And then also we can use other known species from other places as well. So fill in the gaps.
RB: And I suppose if you’ve got a disarticulated skeleton, sometimes it must be hard to know whether you’ve got a new species of or not until you get enough of the bones out to be able to compare to known species.
EK: Yeah, sometimes. So often what you want is definitely some part of the head. And the reason for that is because the head there’s a lot of different specialised bones. So there’s a lot of variability in the bones that can tell us how it might differ from another species, but also want some of the body, because otherwise, which is a problem you always have everywhere in the world with species. Any animal that was a long neck with a small head on the end is very seldom find both of them together because the head when it dies it will bloat and float is what they call it. So when they die they start decomposing and inflates and it floats around in the water. And as the rotting the head will be one of the first things to fall off or get eaten off. So often what you’ll find is a body with no head or you might find a head with no body. And that’s the problem we had here in Queensland as well, we have two long-necked species of plesiosaur – one with a body and one without a body. So we don’t know whether that head belongs to the body with no head unfortunately.
RB: That’s why you keep hunting. Right.
EK: That’s I’ve got to find that one little Rosetta Stone that has both.
RB: Excellent. Excellent. So is there a stage beyond this I guess once you’ve put the bones back together. Is there a way to preserve this digitally?
EK: In the last couple of decades, things like 3D modelling have become much more popular and much more advanced than it’s been and in palaeontology as well we have found much use for this as well. So we can make 3D models of all our fossils and create a virtual copy, so which is not just good for showing people how cool this is, but you also can get with a virtual copy to ensure that you have a record of that fossil for the future. So if anything should happen to the fossil. I’m not saying that it would, but it does happen that fossils go missing or they get destroyed, whether it’s a natural disaster or whatever they might get destroyed. And that is good to have at least a virtual copy to ensure we have a record of exactly how the fossil looked like, but also it allows me to, for instances, collaborate with someone from across the world with another plesiosaur researcher. I can say, hey, look at this plesiosaur we have. Would you like to work together on that? Because they might have something similar to mine. So we can both sit there and study the same specimen without actually being with the specimen, which is a very, very good way of doing it. And then we have C.T. scanning. You can look inside specimens and look at the internal structures. You can 3D print things that you wouldn’t otherwise be able to see without destroying the specimen. For instance, a brain case, a lot of studies have been done recently on dinosaur brains. So you can print out the brain case and look inside the head of the dinosaurs, figure out exactly how the brain looked. And from there, we can sort of produce which senses were enlarged. For example, we get T-Rex at a large factory or smelling sensoring in its brains. Now, he had a really good sense of smell and so on and so on. So there are lots of cool things you can do with his new 3D technology.
RB: Yeah, I think that’s great that we bringing dinosaurs into the 21st century, particularly the fact that you can essentially send them to the Cloud. Look, Dr. Espen Knutsen, thank you so much for joining us from the Museum of Tropical Queensland for our Museum Revealed podcast. What did you uncover this episode? Interested in learning more? Well, follow the Queensland Museum on social media @qldmuseum or head to our website qm.qld.gov.au And while you are there sign up to the e-news list, so you can stay up to date with absolutely everything. Until next time. Stay Curious.