Fossil fever: scientists dig in

We're in the midst of a palaeontological boom...
06 June 2023
Presented by Chris Smith
Production by James Tytko.


The skull of a carnivorous dinosaur.


Researchers around the world are naming a new kind of dinosaur every week on average at the moment - what's behind this golden age of palaeontology? We talk to scientists, museum staff and amateur fossil hunters to find out about some of the most recent breakthroughs in the field, including new techniques looking for fossilised DNA still present in the samples stored away in curators' collections...

In this episode

Amateur palaeontologists

00:53 - Grass roots fossil finding

Inspiring you to give palaeontology a try...

Grass roots fossil finding
Lucy Muir, Joseph Botting

Now, you might remember that we spoke to the husband and wife team, Dr Joseph Botting and Dr Lucy Muir, about their incredible fossil find. I'm delighted to say that they join us again to tell us about their fascination with fossils...

Lucy - The group I work mostly on are things called graptolites which are a largely extinct group. And the particular ones I focus on were planktonic, so they lived floating or swimming in the sea rather than on the sea bottom. So there's quite a lot of those around. So that's mostly what I do. I'm also interested in the total communities. Just anything that we can find in the rocks is of interest.

Chris - So you're both united by the ocean and marine life of days gone by, but at a slightly different size scale I would guess. You are talking about plankton, which presumably are microscopic?

Lucy - The particular plankton I work on, they're actually quite large. The longest are something like a metre and a half. And most of them are a few centimetres.

Chris - You know what they say about archaeologists who are couples - that actually it's a very good thing to be married to an archaeologist because the older they get, the more interesting they get. And that's something that many couples say doesn't happen in their relationships, I suppose with you guys, that must happen as well?

Lucy - Yes! Well, Joe's grown an impressive beard as he's got older and the beard in fact looks remarkably like the fossils he found about a few weeks ago, so he is getting even more interesting!

Chris - How did you both get into this subject? What drew you into the world of palaeontology in the first place?

Joe - I started quite early. I was one of those children that was just looking into anything natural history; turning over logs and stones and peering into the undergrowth. I found my first fossil when I was about five and never really stopped. I didn't really take it seriously as a career until I went to university and realised you could actually get paid to look at fossils, which was a bit of a novelty. I switched from theoretical physics, which is what I went there to do. I found that the maths was too hard for that and the fossils were actually much more fun.

Chris - Were you the same Lucy?

Lucy - Not quite. I actually went to Cambridge to do plant sciences. I grew up in an area without many fossils at all, so I never went fossil collecting as a child. But when I went to Cambridge, I needed a third subject in my first year, and I didn't really want to do more chemistry, so I thought I'd do some geology for the year, it would be interesting. And after the year I just stuck with it and ended up specialising in palaeontology.

Chris - And the rest, I suppose you could say, is history. But in the case of palaeontology, very long term history, isn't it? What would you say to people who are aspiring palaeontologists who are interested in this field, how do you get into this? Where's a good place to start?

Joe - It's one of the very few sciences that you can do with virtually no resources. So the way to start is just to go out looking at things, and there's an old adage that the best geologist is the one that's seen the most rocks, which is not technically true because it's quite possible to look at a rock and not think about it in the slightest. But you can spend a lot of time looking at outcrops trying to interpret them, and the more you do that, the more it starts to make sense, the better your eyes get, the more you start to be able to see things. And it's really interrogating everything you see, trying to interpret what these rocks and the fossils in them actually mean, which lead you to starting to understand it.

Lucy - And I would add that there's, thanks to the internet, so much good stuff about palaeontology out there. There's YouTube videos, there's blogs, you can read a lot of these scientific papers online. So it's really possible to learn a lot about palaeontology just from your computer. So I'd urge anyone who's interested just to read as much as they can.

Chris - I completely agree that the amount you can learn off YouTube these days is absolutely phenomenal, isn't it? It's interesting that given this is such an old discipline in terms of what you're studying, how young it is as an area of study in the sense that although people stumbled on fossils thousands of years ago, they didn't really know what they were or gave them much thought. And it wasn't really a scientific discipline, correct me if I'm wrong, until the Victorians came along?

Lucy - Pretty much and people, as you say, have been collecting fossils back to the stone age. There's trilobites in stone age burials. But realising that they were the remains of animals and plants was really a 19th century thing.

Joe - There was a book by Adrienne Mayer, 'The First Fossil Hunters', where she actually traced back a lot of ancient mythology to fossils. So the idea for the gryphon, it seems, came from the skeletons in the Gobhi Desert on the Silk Road guarding their eggs. So in a sense that was actually palaeontology, it was taking fossils and interpreting them as living animals and reconstructing what they might have been like. Dragons too are another option that's probably from dinosaurs.

Chris - Was Charles Darwin cognisant of fossils? Did he use them to reinforce his arguments or did he not have any ability to put a date on them and therefore they weren't so useful to him?

Lucy - Bit of both. Darwin was actually a very good geologist and he's famous for collecting various fossils on the voyage of the Beagle. It turned out to be quite important but, at the time he was working, geology was still being worked out. So people knew that the earth was old, but not how old. And this is before we had things like radiometric data to get an absolute age. So you could say this rock's older than that one, and that one's older still, but you didn't know how old any of them were. So Darwin tried to calculate based on how fast the land was eroding, how old the earth might be. And I think he came up with something like 40 million years, which as we now know is far too young, but at the time that seemed really, really old. So he was definitely thinking along the right sort of lines. But of course we now know a lot more.

Chris - And technology has helped enormously. I presume your field must be one of the beneficiaries of the sorts of technologies that we can throw at this now.

Joe - Yes, there are so many new imaging techniques that are being used, Micro CT for three dimensional things, with synchrotron, you can blast very high energy rays at tiny fossils and see inside them, even just standard microscope technology and electron microscopes. It's all allowing us to go back to all fossils, which have not really been studied in that level of detail, and interpret them in entirely new ways. So it's showing us entirely new ways of looking at things which would previously been ignored for being too small or not obvious enough. It's only the last few decades that we've tried to study these very difficult fossils, and that's where most of the interest is coming from.

Lucy - I'd say there's still a lot of room for the good old fashioned going out with a hammer to find yet more fossils. We still need more stuff to study so please go out and find more.

Fossil collection

So what exactly is a fossil?
Paul Barrett, Natural History Museum

James Tytko has been speaking to Professor Paul Barrett who is a dinosaur expert at the Natural History Museum...

Paul - Fossils are the remains of past life, often animals that are completely extinct that have no living counterparts and they can be any part of an organism. So they can be shells, they can be bones, they can be fossil leads, they can be pollen, they can be the microscopic insides of single cell organisms. All of them are essentially the hard parts of those animals that, over time, have become replaced by minerals and turned to rock. There are a few other, rarer fossils that we get that are things like soft tissue fossils, things that preserve the insides of an animal like organs or things like skin or fur, but these are much, much rarer and get preserved in lots of very different ways to do with the chemistry of the rocks that they were deposited in. Most of the fossils we have are the hard parts of an organism. And generally all of the soft, squishy bits are long lost to the ravages of time.

James - Let's take those hard bits, the bones, the skeletons. What is the process by which they're usually preserved over millions of years?

Paul - So the main way in which any of these things get preserved is that the animal dies somewhere where there's active sedimentation going on. That is the deposition of things like muds and sand and gravel so that the remains get buried very quickly, they're not on the surface too long for scavengers and wind and rain and weather to affect their appearance. And as they get buried, they become encased in the rock as it forms. Over time, those sediments are compacted, lose water, change their minerals slightly and turn into rock. And the bones or shells preserved within them also change. On a molecule by molecule basis, those original organic components of bone and shell are replaced with rock forming minerals to form an exact rock replica down to the microscopic level of what the original shell or bone used to look like.

James - And where is it that we are most likely to find these rock replicas of the bones and shells?

Paul - Mainly in rocks we call sedimentary rocks. These are rocks that are deposited by rivers and lakes and in oceans and that formed by the accumulation of sediment. They're found in various other places as well, such as deserts, a couple of other places on land. So that's the first thing you want to find. And then, depending on the type of fossil you're interested in, you need the rocks to be at the right age as well. For me as a dinosaur worker, I'm particularly interested in rocks that date from the Triassic, Jurassic and Cretaceous periods between about 240 and 66 million years ago, which is when dinosaurs were alive.

James - When we talk about how they're found, this discipline that we know as palaeontology, when did this all begin? How long have we been looking at the fossil record for evidence of what life was like on earth all those years ago?

Paul - So people have been finding fossils as long as there have been people. And we have examples from very early human sites where fossils were obviously picked up because they were realised to be something unusual or something curious. But the scientific study of fossils really only goes back a couple of hundred years. So a few pioneers, people like Leonardo Da Vinci in fact, were already speculating about fossil remains, wondering why these shells turned to stone appeared at the top of mountains long ways from ocean. But it's only really in the 19th century where we also have the development of various other branches in science, in particular geology, that starts to give us an idea about the age of the earth, the length of time that there has been for animals to appear and evolve and also developing ideas about evolution. And as a result, we've really only started to think about them scientifically for a couple of hundred years and bring them into this bigger view of the evolution of the earth as a whole and also their influence on what we know about the evolution of life.

James - And then fast forward a couple of hundreds of years: dinosaurs, they're a staple of any natural history museum, let alone the Natural History Museum where you are speaking to us from. And I understand you've got a brand new exhibit at the moment. Can you tell me a bit about it?

Paul - We do. Dinosaurs always capture the imagination, partly through their bizarre appearance and size. They're a very good gateway for getting people interested in thinking about past lives and aspects of earth science and biology that stem from those. So at the moment we have a big new exhibition that's only been open a month or so so far, which is called Titanosaur. Titanosaur focuses on one particular dinosaur, an animal called Patagotitan, which is from Argentina, which is a contender for the crown of the largest animal that's ever walked the earth. And I'll be very specific when I say "walked the earth," this is in terms of an animal that lives on land. So the largest animal ever is a blue whale, which lives in the sea, but living on land poses a large number of extra challenges to becoming big. And Patagotitan is an animal that may well be pushing at the envelope of the very largest animals ever.

James - Incredible. What did it look like?

Paul - So Patagotitan was what we call a sauropod dinosaur. These are the dinosaurs with large barrel shaped bodies, very long flexible necks and tails, and four stout columnar legs. And there are a lot of famous examples that people might be familiar with, like diplodocus for example. So it's a member of that general family of dinosaurs. It's a very large example. We think it weighed about 57 tonnes and was about 37 metres in length. And to put that in some perspective, that means it weighed about the same as eight or nine fully grown African elephants. And actually it's about 10 metres longer than our beloved diplodocus replica that we have at the Natural History Museum. So these are really gigantic animals and you get a sense of the scale of them when you walk up to it and you realise your head just about comes up to its knee.

An artist's rendition of a spinosaurus.

15:10 - Cretaceous creatures discovered this week

Some of the exciting research published from the world of palaeontology...

Cretaceous creatures discovered this week
Adele Pentland, Curtin University & Neil Gostling, University of Southampton

We want to give you a flavour of just how busy a time it is for people trying to keep pace with palaeontology at the moment. Researchers around the world are, on average, naming a new type of dinosaur each week! We’ve decided to spotlight two studies published just in the past few days with the scientists involved. While finding new species is always exciting, scientists are also interested in further illuminating the history of the animals we already know existed.  James Tytko with this…

James - Paleontology is booming. An offshoot of the public’s demand for dinosaurs - fuelled by Hollywood blockbusters and big budget documentaries - is the ever increasing number of researchers rifling through museum collections to reassess old specimens in a bid to unlock new perspectives on the ecosystems of the past. 

Adele Pentland from Curtin University in Australia, has been doing just that. For the study she’s published this week, she’s been looking at 2 fossils unearthed many years ago…

Adele - So the specimens were discovered in the late 1980s at a site which is now called Dinosaur Cove. Since excavations were conducted, they have uncovered hundreds of fossil specimens from dinosaurs, early mammals, freshwater pleisiosaurs, crocodiles, and some rare pterosaurs.

James - Pterosaurs are exactly what Adele is interested in. These flying reptiles populated the skies at the same time as the dinosaurs were roaming around on land.

Adele - Often people will call them pterodactyls, but calling the entire group pterodactyls is like calling every single dinosaur tyrannosaurus. They are different to dinosaurs. They're not flying dinosaurs and they vary quite a lot. Some have wingspans of 30 centimetres, whereas some of the big ones have wingspans of 10 metres. So some of the smaller ones eat insects, the group that I mainly work on appear to have eaten fish and then some of the big ones may have been scavengers feeding on carrion.

James - Paleontologists are rarely working from a full body specimen in their research are they? Was this the case this time?

Adele - In the paper we describe two bones. They're actually not from the same individual either. One is a partial pelvis and the other is a small wing bone. Based on comparisons with other pterosaurs from around the world, from the partial pelvis, that individual probably had a wing span of at least two metres, whereas the really small wing bone looks like it belonged to an animal with a wingspan just over one metre. And that is the first juvenile pterosaur that we have from Australia. They're approximately 107 million years old.

James - And if that wasn’t enough fossil news for one week, how about something a little bit closer to home…

Neil - Hello, my name's Neil Gostling. I'm a lecturer in evolution and paleobiology in the School of Biological Sciences at the University of Southampton. Spinosaurs are one of the most exciting, almost definitely one of the most controversial, but one of the most charismatic, I think is a good word, theropods, the carnivorous dinosaurs, that have ever existed. They've got a weird head which is superficially crocodilian, they've got a very elongated face with pointed circular, conical shaped teeth, perfect for grabbing slippery fish. And we know that they were eating fish because there was a specimen, discovered in 1983, called baryonyx, which means heavy claw because they have big old heavy claws as well for hooking. And the fun thing about them, I mean if you want T-Rex and triceratops, large animals everyone knows about, they're North American, but the spinosaurs are European. And the good thing is that we've got quite a few species in Britain as well.

James - James - Like Adele, Neil and his team observed from old specimens that the story of spinosaurs in Britain was not what past palaeontologists might have thought. PHD student Chris Barker made several discoveries from studying fossils stored within the collection of the Hastings Museum and Art Gallery…

Neil - In 2016. We thought spinosaurus living in Britain were baryonyx, that's what it was. Very quickly, Chris identified some unique characters and showed that not only were they different from one another, they weren't baryonyx either. So we went to three species of spinosaurs in Britain. And then, this is really exciting, we found the smallest piece of dinosaur we could possibly have found: a single tooth, but Chris again spent an awful long time analysing it, picking out all of the potential details and analysing those to show that this is also not the baryonyx related group. It is a different animal. We shouldn't, we can't, and we haven't named a new species based on a single tooth, but we've shown that it isn't any of the groups that are alive at the time and that we know about today.

James - So there’s a sample of some of the work that’s just been published in the last week, advancing our understanding of these ancient animals. But running parallel to this golden age of research is the the boom in the price of fossils sold at auction for eye watering sums and going into the hands of private collectors. A swiss auction house sold A Tyrannosaurus skeleton made up of the bones of three different T-Rexes for US$6.1m just last month. I wanted to find out from our scientists how potentially damaging this trade in dinosaur bones is for future work like theirs?

Adele - You may not know, but for a researcher to describe a fossil specimen, as I have done in a peer-reviewed scientific journal, that fossil can't be in a private collection. It has to be in a museum collection because the concern is that that fossil needs to be accessed by everyone. It can't just be in the control of one person and they can't just let their friends study it and not let you know other people who might contradict them not look at it. That's not how science works.

Neil - All of the work that I've been doing has been on publicly owned collections and yeah, we're trying very hard to democratise science and make it available. The paper that came out today about the tooth is freely available and unfortunately, if things go into private collections, no one can do anything with them. No one can see them. And it's a very great shame.

The skull of a carnivorous dinosaur.

22:07 - Will we ever see dinosaur DNA?

How has our understanding of fossil chemistry changed over time?

Will we ever see dinosaur DNA?
Landon Anderson, North Carolina State University

In recent years opinion has shifted to accept that even ancient fossils most likely also contain some of the chemicals that were present in the original lifeform, including proteins, fats and possibly DNA. This is known as molecular palaeontology. Landon Anderson works on this at North Carolina State University where he’s currently finishing his PhD…

Landon - You know, when someone would go out into the field and dig up a fossil, sure it would have the shape and structure of a bone. But the general view on that was that minerals had come in and replaced the original organics that were there and that would now just be a replica of the original organism, skeleton, or bone. And that was for a while, the general view of what a fossil was.

Chris - So it was the form, but none of the fabric of the thing that had once lived.

Landon - Yes. And even for a while, we didn't even know whether the original, like microscopic structure of the bone itself was preserved. Do you know where all the blood vessels had been or, you know, the cells in the bone had been, whether that was preserved as well.

Chris - So when did that begin to change? When did our view begin to shift?

Landon - That view, that the overall fossil bone is not just a rock replacement or mineral replacement of what was originally there, changed roughly around the turn of the 1900s to the 21st century when paleontologists began to look at the microscopic structure of fossil bone, or fossils in general. For example, if they had a bone of a dinosaur, they could take thin sections of the bone and look at it with a microscope. The actual tissue structure was at least replicated in minerals. So you could see what the structure of the bone was like when the organism was alive. That was sort of around when we started to figure out there might be something more to these fossil bones than we had previously thought.

Chris - And what was that insight or what data or discovery began to provoke people to think that this isn't just well preserved micro structure, that there are things in there that might be part of the original beast or being that gave rise to that fossil?

Landon - The major discovery is around 2005, Mary Schweitzer actually reported out of a T-Rex bone from the Hell Creek in Montana, the presence of soft, flexible blood vessels and cells and really changed the way that paleontologists kind of viewed fossils in general. They weren't just these mineral replicas of the original organism, but some of the original tissue might be there. And if that's the case, then there's a chance that it can tell us what it looked like and how it lived back when it was alive.

Chris - I met Mary Schweitzer about six or eight months after she published that paper you just referred to. And she told me that the scientific community, when she stood up at a conference andsaid, I think I've got original tissue from a T-Rex, people laughed at her and told her she was misguided and must have done her experiments wrong. Presumably that view has now changed.

Landon - Yeah. When Dr. Schweitzer first recorded her findings, there was a lot of controversy. One of the main ideas or hypotheses proposed to explain the soft tissues in the case of they weren't original soft tissue, was that they might be bacterial biofilms. But over the years that has been tested and the data in general supports that these are indeed the original soft tissues scientists are finding in these bones.

Chris - I almost feel like it's sort of bringing colour television to previously black and white images. It's almost like another dimension in paleontology that we are into now with this. So what can it add that we couldn't get just by looking at structure before?

Landon - Well for one, just for like the organismal biology, these ancient organisms in general, we can learn things about them through their soft tissues and the chemicals preserved in them and that we otherwise would have no other way of knowing. So it can tell us a lot about their biological adaptations to their environment, kind of how they lived.

Chris - DNA must be one of the holy grails here, a horrible phrase, but it must be one of the things that's a target because it can tell us so much about the evolutionary history of an organism, where it came from, who it's related to and so on. We are in the sort of million year regime of published data on ancient things with DNA in them. Do you think it's feasible we're gonna see T-Rex DNA in the near future?

Landon - Oh man, that's a big question. Everyone likes to know the answer to will we ever get dinosaur DNA and after that, obviously whether we'll ever be able to clone dinosaurs. There are studies out there, one recently published that reported not DNA sequences, but the presence of some structure that may be DNA. They haven't actually sequenced it yet, but they used a chemical that binds specifically to the double helix structure of DNA and they were able to show that this chemical actually bound to a specific location within what they reported as cartilage cells from a duck-billed dinosaur. Will we ever be able to sequence that? That's a whole another question because to sequence DNA, the reactions necessary require it to not be heavily damaged. And obviously to get that in a dinosaur fossil, pristine DNA, it's a bit of a challenge.


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