Mark Witton

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Moira: 00:00

Doctor Witton, welcome to Tech Nation.

Mark Witton: 00:02

Thank you very much for having me.

Moira: 00:04

Now if anyone has watched Jurassic Park three, they would see the kind of dinosaur we're talking about today, the Spinosaurus having a huge fight with a Tyrannosaurus rex, you know, that big guy with the little arms. So what does Spinosaurus look like? And, from what we know, how accurate is the film? And, say, what were the liberties taken for the movie's sake?

Mark Witton: 00:31

Jurassic Park three is a great point to start this conversation because it's the film that put Spinosaurus on the map. So we actually first found Spinosaurus all the way back at the start of the twentieth century, but the material we had for this animal was not complete enough to give a really accurate idea of what it looked like. By the time we got to the 1980s and 1990s, we started discovering more Spinosaurus in general. So these aren't Spinosaurus, but they're related species, and they gave us enough of an idea to say maybe what Spinosaurus itself looked like. We always knew it gonna be a cool dinosaur because the the material we found in the '19, nineteen tens had this big sail down its back, and it had this very narrow, slender jaw.

Mark Witton: 01:10

So it was always clearly gonna be an interesting predatory dinosaur, but exactly what it looked like wasn't revealed until decades after. And so what was created for the film was this very large, so bigger than T Rex, a very large or certainly very long dinosaur with a a very long slender face. Some people compare them to sort of crocodile like faces, which is somewhat apt. You could call them crocodile like, but you could also call them sort of rather bird like. They're very narrow.

Mark Witton: 01:38

So if you look at something like a heron, heron has very narrow face and so does dinosaurs. They also have these very long necks. They have, robust arms, so they're, unlike something like a Tyrannosaurus. They have these long three fingered arms, and there is a a large claw on the, on the thumb. So they're they're quite a distinctive group of dinosaurs, and that's what they put together for for Jurassic Park three.

Mark Witton: 02:05

But what what they were lacking were some of the information that we have now. So we can look back at Jurassic Park three, which is producing something like 2,000, and, we can now already say even just, you know, a couple of decades on that that depiction is quite dated. So we know that the legs are far too long. They made the sail too small and the wrong shape, and they also made it far too bulky. So spinosaurs, as it turns out, are actually quite slender dinosaurs.

Mark Witton: 02:29

They're still very big. And so to look at one, wouldn't necessarily go, that's a slender dinosaur. But if you know your predatory dinosaurs well, you would look at them and go, yeah, they're they're they're not they're not particularly big and bulky. So ironically, the new Jurassic Park film that has just come out, last year, they've already had to start revising their Spinosaurus compared to what it was back in 2000, so already in a realm where that original JP Spinosaurus is already being dated.

Moira: 03:00

And did they get it right? Is it bigger than the Tyrannosaurus rex?

Mark Witton: 03:03

So, yeah, we've got new material Spinosaurus now that certainly confirmed. It's always been known it was gonna be a really big predatory dinosaur. So initial estimates put it at something like 12 meters long, a very conservative estimate. So that's already about the same size as a big T. Rex.

Mark Witton: 03:20

The material we have of Spinosaurus now suggests that it might be getting to maybe sort of 14 meters long, but the thing to emphasize here is that size, of course, is not just measurable in terms of length. In fact, length is not a particularly useful metric for determining the size of an extinct animal because you can be long and skinny, and it doesn't necessarily mean that you're particularly big. It's something like a snake, for instance. A snake is an incredibly long animal, but that doesn't mean it's necessarily a particularly big animal in that it's not particularly massive. It's not particularly heavy.

Mark Witton: 03:50

So with spinosaurs, yes, it's probably one of the longest theropod dinosaurs or predatory dinosaurs, but it's probably nowhere near as as heavy as something like a T. Rex. You know? If you have have two animals of the same length, the Tyrannosaurus is gonna be heavier than the Spinosaurus is.

Moira: 04:07

So for the Tyrannosaurus, don't let those little arms fool you. It's a big it's a big dinosaur. And then let's convert that the the meters long to feet so people in the who operate in a in a different scale can do. What's the difference between which 12 meters versus 14 meters?

Mark Witton: 04:27

So, yeah, if if we're talking just very roughly, we're talking about three feet per meter. So if we're talking about 12 meters is about 36 feet. With spinosaurs being sort of 14 ish meters, we're looking just over 40 feet. That sort of, you know, maybe maybe 42. The the thing to emphasize with this is the there are big error bars on the estimates.

Mark Witton: 04:47

So something like a T Rex, we can be very confident about the the total length of that animal because we have complete skeletons for it. So we have a really good fossil record for Tyrannosaurus, and this includes many complete specimens. We have, lots of really particularly mature Tyrannosaurus individuals, those that have grown to their full size, so they're never gonna get any bigger. And so we know that that animal is maxing out about 12 and a half meters, so sort of maybe maybe 35 sorry. Maybe about 37 feet or so.

Mark Witton: 05:18

That's not to say there's not bigger ones waiting to be found, but with the sample size we have, that seems to be about the the upper the ceiling for them at the moment. But the big the biggest specimens we have for Spinosaurus, they're bits and pieces. They're like the the biggest specimen we have is is actually just half the snout. So to get these size estimates, we are having to extrapolate, you know, considerably from very small amounts of of information. We also still don't have a complete spinous or a skeleton, which means that any estimate we have about its length is based on it's an extrapolation based on a reconstruction.

Mark Witton: 05:52

So there's just levels of inference and and and educated guesswork involved at every point of this. So I don't think the size of the bones we have for Spinosaurus, those really big ones, is clearly going to be an absolutely enormous animal, which is putting it in the, you know, in the competition for what's the biggest predatory dinosaur, certainly what's the longest predatory dinosaur. But we don't have, you know, full confidence about exactly what size that is yet. We need more material before we can have that conversation. And that's this is actually a really common thing, about dinosaurs and other extinct animals in general.

Mark Witton: 06:27

Everyone wants to know what's the biggest one. You know, what's the what's the longest dinosaur? What's the heaviest dinosaur? Well, the bones we have from all the biggest ones, they tend to be really fragmentary. So we are extrapolating those metrics from smaller relatives that we have a better understanding of.

Moira: 06:44

Now where in the world did spinosaur live? Is spinosauri? Like, what would it be? Spinosauruses?

Mark Witton: 06:54

Yeah. So it really depends what we're talking about because there's spinosaurus, which is a genus of dinosaurs. So it's a, this is a there's two species of spinosaurus now. There's spinosaurus aegypticus and there's Spinosaurus marivalis. They're from Africa, so Spinosaurus is originally from Egypt.

Mark Witton: 07:11

Exactly how far it spread across Africa is controversial. Some experts think it was quite ubiquitous across the northern part of the continent, so you could find its remains all the way from Egypt over to Morocco and in the countries in between. Other people think that maybe it's you know, maybe there's more endemism going on, I. E. That maybe Spinosaurus aegypticus is just restricted to Egypt, and the bones we find in Morocco belong to a different species.

Mark Witton: 07:39

And there's about as many different opinions on this as there are people who work on Spinosaurus. It's quite a contentious issue at the moment. But there is a wider group that spinosaurus belongs to, and that is called the spinosaurids. And this is a is a group that they all look pretty much like spinosaurus, but most of them don't have the big sail on the back. Most of them are also considerably smaller.

Mark Witton: 07:59

So we're still talking about fairly large animals, you know, compared to our modern fauna. We're looking at animals, you know, sort of eight, nine meters long as adults. So they're still pretty big, you know, pretty big animals, but they're not getting up to twelve, fourteen meters or so. So the and and these other these spinosaurids are found around the world. So you find them in South America.

Mark Witton: 08:19

You find other non spinosaurus spinosaurids in Africa. You find them in Asia. You find them in Europe. The one place we haven't found them is North America, and it's peculiar. This is, something of a you know, it's it's perplexing to us as paleontologists because we're thinking, well, why aren't they there?

Mark Witton: 08:40

Because all the other animals that spinosaurs are contemporary with, the other dinosaur types that they lived alongside, they all occur in North America. So it's a bit strange to us that they haven't been found there yet. And so there's a question, is this a genuine, you know, quirk of their evolution that for just some reason they never made it into North America, or is this a sampling question? Is this a sampling issue just that we haven't found their bones yet? Maybe we're not looking in the right deposits.

Mark Witton: 09:07

Maybe, maybe we have found them. Maybe they're lurking in a museum somewhere and just someone hasn't recognized the fossil for exactly what it is yet. So it's, something of an ongoing mystery as to why we haven't found them in North America yet, but it's it's something that people are aware of and they're gonna be keeping their eyes out for. Everyone's gonna want to find the first North American spinosaur.

Moira: 09:28

You're listening to Technation. I'm Moira Gunn, and my guest today is vertebrate paleontologist, doctor Mark Witton. With fellow paleontologist, doctor David Hone, they've written spinosaur tales, the biology and ecology of the spinosaur. So we've actually been talking about the biology of the spinosaur thus far. What is the ecology of a dinosaur and specifically, of course, spinosaur?

Mark Witton: 09:57

So when we're talking about ecology, we're we're thinking about lifestyle. You know? What do these things eat? Where did they live? And we we determine this from fossils through a number of different ways.

Mark Witton: 10:06

So we might look for things like fossilized gut content. Sometimes fossil animals are they they they die with the the remnants of what they ate recently in their stomachs, if we're lucky, that will enter the the fossil record. So we can get a pretty good idea of what they were what they were eating at least at some points in in their lives. We can look at the sediments that they're preserved in. The rock record is not just sort of randomly randomly accumulated.

Mark Witton: 10:31

Sediments that dinosaurs are preserved in reflect the habitats that laid down those sediments. So for instance, if you if an animal is deposited in a in a river, we can identify that river in in the rocks. We actually know what sort of features a river will deposit over the top of a dinosaur. So we can get a pretty good idea of where animals were living, what they were eating, and and use this and other data to put together an idea of what their lifestyle and ecology may have been like. And the interesting thing about spinosaurs is that they're doing something pretty different from all other predatory species.

Mark Witton: 11:04

So if you think about a predatory dinosaur, most of the time, you're gonna be thinking of a a a carnivore like a like a T Rex or like a velociraptor, and these are dinosaurs that are eating other dinosaurs. Spinosaurs doing something different to that, and and we can immediately tell they're doing something different because they look so different. So and this is all because of what animals look like reflects some in in part what we call their functional morphology. So IE, their shape is adapted to do different things. And what we realized with spinosaurs and what has been supported by things like gut content, is that they're probably largely fish eating dinosaurs.

Mark Witton: 11:43

So we imagine them living this is a little bit, again, a little bit controversial. There's lots of controversies with spinosaurs. But, myself and Dave, and other researchers, we imagine them essentially as giant herons. And so they're standing, in in relatively shallow water waiting for fish to swim by, and they're grabbing them. And so they're grabbing them either with their with their long snouts, which are filled with conical teeth that are ideal for grabbing fish, or they're, or they're grabbing them with their hands with those big claws that we mentioned.

Mark Witton: 12:10

And, of course, they might be doing both at the same time. They might be grabbing them with their hands and also with their jaws. There are competing ideas. I feel it's it's, you know, important to mention that there are other ideas available, and so there's, potential, for that spinosaurs were swimming after their prey. There's there's a group of researchers who feel that spinosaurs were more aquatic than myself and Dave feel, and they're actually diving in the water and swimming after them, swimming after after fish and other swimming animals, somewhat like otters maybe, you know, that that they're they're sort of actually going through the water using the paddle like tail that Spinosaurus has.

Mark Witton: 12:48

It has this very strange tail, this, sort of very long, somewhat eel like tail, and they're they're propelling themselves through the water using that to to chase after fish.

Moira: 12:57

Now throughout the book, you have many of your drawings of all kinds since there's always an amount of guesswork here. What are your personal rules regarding what you depict that you draw?

Mark Witton: 13:08

So this is a huge question. I've written whole books on this very topic. So, you know, stop me if I go on for the next four hours. So what I'm producing is something called paleo art, which is a a kind of a a subset of natural history art where we attempt to bring back the extinct organisms and the landscapes they live in using science, and we then take what we know from that science and put it into artwork. So the rules are essentially, well, what does what does science tell us?

Mark Witton: 13:36

What what do we know about these animals from their fossils and from the geological record? And and by by following that information, it means that it isn't these artworks aren't things where sort of anything goes. You're actually trying to be as accurate as you can to the information that we have from the palaeontological record. So for instance, if you're drawing something like a spinosaur, it will mean that, number one, there are some animals that we just can't draw yet because we don't have enough of them. A whole bunch of spinosaurs are only known from things like their jaw tips.

Mark Witton: 14:08

So they might actually be a named animal, it might be a species that we can recognize in the fossil record, but with only a jaw tip, we don't know what the rest of the animal looks like, so we're just gonna say we can't draw it yet. We don't know what the rest what the animal looks like. So number one, we're gonna focus on those animals we know a little bit better. And when we are drawing it, we're gonna pay close attention to things like its proportions. We're gonna look at the skeletons that we have as fossils, we're say, okay.

Mark Witton: 14:32

I wanna make sure that I make sure that the thigh is the same ratio that's the right ratio to the shin, and that the foot isn't too big, and that the snout is, you know, the right length compared to the the rest of the body. And I'm gonna make sure I put it in the right landscape, that I'm gonna look at that those geological features that we just mentioned. What do they tell me about the landscape where that animal lived? I'm gonna make sure it's in that landscape. I'm gonna make sure it's doing something which is biomechanically plausible.

Mark Witton: 14:56

I'm not gonna show it lifting a a fish out of the water that is far too heavy for an animal of that size to be lifting out of the water. So there's all sorts of science that we're following to put these pictures together. It's really really isn't a case of just looking at a skeleton and then letting our imaginations run wild. The idea is to be as as accurate as we can to the to the fossil record.

Moira: 15:16

Now we always think that science just marches forward. It might change speeds occasionally and slow down or really go fast, but we always think it marches forward. It was in the early twentieth century in the in the nineteen hundreds, nineteen tens when the first real collection of Spinosaur specimens were collected, and then a lot of it was destroyed. Tell us about that, and tell us about what we know about what was destroyed.

Mark Witton: 15:48

Yeah. So this is quite a sad story. And as you say, this is really a case of science moving forward and then moving back or or certainly just stopping. You know, the the the when we lose when we lose specimens, which is what happened to the first dinosaur material, you know, it it means that we can't do do testing anymore. Listen to the things.

Mark Witton: 16:06

When we're talking about science, it's not just sort of nebulous thing. Science is a very specific methodology for understanding the world. It's about being able to make, testable observations and and come up with hypotheses based on, testable criteria. So when we lose information, like in this case, losing fossils, it means we can no longer go back and test things in the same way that we were able to when we still had access to them. And of course, the the story of Spinosaurus is wrapped up in the world wars.

Mark Witton: 16:34

So we're talking here Spinosaurus itself was discovered in the nineteen tens. It was shipped over to Germany where it was studied by Ernst Stromer, and he and Stromer produced papers in the nineteen tens and then in the nineteen thirties on on Spinosaurus. And shortly after, he concluded doing all of his work on the these were partial skeletons we had of Spinosaurus, so they were bits of the bits of the jaw, we had the backbones with those distinctive sails that told us Spinosaurus got this enormous sail, And he had a few other bits and pieces, so bits of the limb, some bits of the tail. It wasn't wasn't a huge amount of stuff, but it was enough to give him an idea of this really awesome looking dinosaur. As as shortly after Stromer finished his work on it in the nineteen thirties, of course, World War two began, and the the Munich Museum that held Spinosaurus was struck by an allied bomb in 1944, and it obliterated the the specimen collection of the museum.

Mark Witton: 17:32

So Spinosaurus wasn't the only victim of this. A huge collection of all sorts of artifacts, all sorts of specimens, was destroyed, and this included many other dinosaur species. Spinosaurus is just the most famous dinosaur to have gone have been destroyed in that incident. And, yeah, that was it for Spinosaurus remains for many, many years, and it wasn't until really the 1980s that Spinosaur research started again when we discovered an animal called Baryonyx in in Cretaceous deposits of The UK. So there was this long, you know, forty year hiatus essentially where we weren't able to do anything on spinosaurs.

Mark Witton: 18:10

After we found Baryonyx, people got excited about spinosaurs again, and we started finding more spinosaur material, particularly in Africa, but eventually in other parts of Europe and Asia and South America. And so there was sort of a resurgence of interest in them. But, yeah, for much of the twentieth century, you know, there wasn't much to say about Spinosaurus because the the only remains we had had been blown to bits.

Moira: 18:31

Especially if he was the longest or the or the highest or however the you're always looking for the the boundaries for popularity, you know, that it could have been a different thing as opposed to the first thing you say is T Rex, could have been spinosaurus.

Mark Witton: 18:46

Absolutely, and one of the there's a really good case to be made here for documenting your work well. So if you're a scientist, the best thing you can do as a scholar is to do your work early and do it thoroughly. So the guy who was working on Spinosaurus, as we've already mentioned him, his name was Stromer, He was a very meticulous, very thorough researcher. And so what what we're left with of that original Spinosaurus inventory are Stromer's papers. And in that, he provided lots of measurements, lots of really good illustrations, lots of really good descriptions of the Spinosaurus bones.

Mark Witton: 19:26

And so while we don't have the original bones left to study anymore, we do have a lot of information still about them. It's still the runner-up prize compared to having the actual bones to work with because there's always things that are of, you know, new interest to us. There's always things that we now know about that Stroma didn't know about and techniques that we have available to us that Stroma didn't have. So there's there's plenty of stuff that we would really love to be able to do with those original Spinosaurus, bones, but, you know, at least having Stroma's good descriptions has given us something to work with. And in many cases, you know, we're still having to use that a lot.

Mark Witton: 20:01

You know, when we when we ask ourselves, we got a new dinosaur and we're asking ourselves, is this thing Spinosaurus? The thing we have to go back to is Stroma's description because that specimen carries the name of Spinosaurus. So that's what the when we were talking about naming species and things, they're attached to what we call a holotype, which is the original specimen that we found, and it's the one with all the characteristic bits on that says this is what Spinosaurus looks like or this is whatever, you know, whether it's a Spinosaurus or a chipmunk. Somewhere, there is a holotype for chipmunks where people go they need to know what the chipmunk is. They go back to that original specimen.

Mark Witton: 20:36

They go, does it have all the features of that chipmunk? So for Spinosaurus, we have to go back to Strom's original descriptions to know if our new dinosaur belongs to that same species or if it's something new. So it's still something that we're referencing a lot today.

Moira: 20:51

So you're referencing what he wrote down, but you can't go back and look at his specimen.

Mark Witton: 20:55

That's correct. And this is one reason that Spinosaurus is such a controversial animal. We mentioned that there's discussions about is Spinosaurus restricted to Egypt, or is it found elsewhere in Africa? I said, well, we know that it's in Egypt because that the thing the bones that came from Egypt are the name bearing bones. So it's definitely in Egypt.

Mark Witton: 21:13

But the things we found in Morocco, you know, it's thousands of miles away. Do they belong to the exact same species as the one that is found in in Egypt? When you've only got pictures and only got descriptions to work from, you know, it it can be difficult to to to make these kind of calls. A lot of dinosaur species are diagnosed by surprisingly small features. It might be, you know, little little grooves, little lumps and bumps that are very difficult to see if all you've got is a sort of one particular view of a bone.

Mark Witton: 21:45

You might be able to look at that bone from a particular angle that we no longer have. So, it's tricky thing to work with, but we're, you know, as with all things in science, you just do the best you can with the information you have. What would be really useful is to go back to some of those deposits in Egypt and to find more bones that belong to Spinosaurus. And people have tried to do this, and they've they've, they've not been able to find more remains of Spinosaurus aegypticus yet. But, yeah, who knows?

Mark Witton: 22:14

One one one day in in the future, may maybe we'll we'll be able to get there.

Moira: 22:18

Well, I have to say, it's always hopeful. Everything you have is yet, maybe soon, maybe sometime.

Mark Witton: 22:26

Indeed. Yep. And who knows what's coming tomorrow. Right? That's the thing in science.

Mark Witton: 22:29

You never know what's around the corner tomorrow.

Moira: 22:32

Now let me ask you. You're not getting any DNA here. That's there's no possibility for that, is there?

Mark Witton: 22:38

It's far, far, far too old. So we're talking here about animals that are living, between sort of a 130 and and a 100,000,000 years ago. So these things are very, very ancient. DNA, at most, survives to about 2,000,000 years ago, and even that is a real push. And that that you you find DNA of that vintage only in very specific preservational conditions.

Mark Witton: 23:03

So you're talking about things like permafrost, you know, where where animals have literally become entombed in ice that is now underground. So the sort of deposits that you've got in Alaska and in, in parts of Siberia, you might be able to extract DNA from fossils that are of animals that died thousands of years ago in caves and that they're they're in such dry conditions that the boat that the the you know, things like their their skin are still preserved. So you might be able to get genetic material from that. But, yeah, anything older than that, genetic material degrades pretty quickly, so it's very difficult to to, to to get anything meaningful from, from from dinosaurs of that age. We are learning that we can get more, It's not quite genetic material, things like pro proteins.

Mark Witton: 23:51

We're we're now being able to get chemical traces of things like proteins from dinosaurs, but we're we're not necessarily talking about the original proteins. We're talking about the degraded remnants of proteins. So we're not able to look at that and go, oh, that's necessarily that protein exactly. We are able to do really sophisticated things with, you know, recovering geochemical traces of things now, but we're a far cry from things like Jurassic Park where they're, you know, able to take whole DNA strands and clone animals back to life. I mean, that's a whole conversation in itself about cloning extinct animals.

Mark Witton: 24:26

Just the the the the the briefest point about this is that the sort of DNA that we have in fossils is nowhere near the sort of quality that you need to bring an animal back to life. If we had fossil grade DNA in our cells, we would be in serious trouble. We you know, you need a perfect genome for something to be a viable functioning living organism, and the sort of stuff we find in fossils has been left out in the rain for thousands or millions of years, so you don't want that as the basis of anything to bring something back to life.

Moira: 24:55

Now final question, and that is today, we we think about the earth, the whole earth, and we think about the dirt because that's primarily where people live. And we can see how or we can think about how there are people all over the earth. They're they're not a lot of them high in the mountains. They're they're mostly on flat lands. They're if we just think about the earth, we can see where all the population is and not equally distributed, but it is all over the earth.

Moira: 25:25

Back then with the dinosaurs, were there dinosaurs everywhere?

Mark Witton: 25:29

Yep. Absolutely. Yeah. Yeah. I mean, the fossil record is incredibly biased, so it's difficult to say exactly how many dinosaurs were living in place like mountains because mountains it's it's, you know, it's quite quite logical to think about this.

Mark Witton: 25:46

Mountains are big upland areas, and they are eroded by wind and rain. So you get very few fossil deposits left by by animals that are living in mountains because anything that that died up there in fossil ice has been worn away by erosion. So we only get snippets of things like mountains. The same is true for, things about things like tropical islands, which are these volcanic islands that may burst out of the oceans, and then they they will survive for as long as they are not eroded away by the sea or subducted under, you know, into, what what am I thinking of, subducted under con under continental plates and this sort of thing. So there are some sort of habitats that we don't get represented that well in the geological record.

Mark Witton: 26:33

But what we can say is that, well, from the evidence we have and it's pretty good. You know, we have evidence of of deserts and of forests and of flood plains and, of cool climate areas and these big cool kind of tundras. All sorts of things exist in the fossil record, and wherever they occur, you get dinosaurs there. You know, dinosaurs were as common in the Mesozoic era, so we're talking here the the time 250,000,000 years ago to 66,000,000 ago. Dinosaurs were as widespread in that time, as mammals are today.

Mark Witton: 27:04

You know, they're occurring just about everywhere. Only place you wouldn't find dinosaurs or at least certain types of dinosaurs, you don't really find them in the sea. So dinosaurs never got into the oceans. At least, the non bird dinosaurs didn't. The dinosaurs have finally got through that barrier and and evolved to learn to swim and and and live out, you know, living out to sea long term are the birds.

Mark Witton: 27:27

So, of course, birds are are are modern dinosaurs. They are related. So there's the same dinosaurs that we're discussing today, things like spinosaurs. Birds are descended from the predatory dinosaur line, and it was as birds that dinosaurs learned to swim properly. So even before the big extinction that wiped out all the non bird dinosaurs, we already had aquatic birds.

Mark Witton: 27:47

There are great big, like, six foot tall birds called Hesperonis from North America, and they're diving into the water, and swimming around shallow seas. There are possible remnants, relatives of of modern ducks and geese that are around before the end of the, of the Cretaceous that are also, you know, swimming around, sometimes diving under the water. So it's, it's quite a it's it's strange that dinosaurs didn't learn to do this before birds got there, but it's the one thing that they they never managed to do.

Moira: 28:17

I gotta say, I'm still a little stunned. We were really a dinosaur planet.

Mark Witton: 28:22

Absolutely. Yeah. Even even, even places that that historically we thought dinosaurs couldn't get to. So, you know, for a long time, it was thought the dinosaurs were cold blooded, and therefore, you'd never find them in places like Antarctica, or you'd never find them at really high latitudes in, places like Alaska. And, of course, we've got to remember that millions of years ago, the climate wasn't what it is today, so we didn't necessarily have ice at the poles.

Mark Witton: 28:45

We weren't we're not necessarily talking about Antarctica as we know it, but we're still talking about somewhere that is far colder than it is in the tropics and and, you know, maybe would be cold enough to deter the presence of things like a cold blooded animal. But, nope, we find them there too. So we find them at the high latitudes. Yeah, they were clearly a very adaptable, warm blooded bunch that were able to live basically wherever they could eat out a living.

Moira: 29:12

Just like us.

Mark Witton: 29:14

Just like us. Yep. Just like us. Just as adaptable as mammals and birds are today.

Moira: 29:19

And we've only been around, what's it, forty thousand years? Fifty thousand? What would you call it? What would you put the number at?

Mark Witton: 29:24

It depends where you wanna draw the line between yourself and our close ancestors. But, yeah, generally speaking, homo sapiens sapiens, the form of human that we represent, we're probably, you know, a 100,000 years old or something like that. Are a new species. Compared Yeah. To dinosaurs we are, you know, very, very new.

Moira: 29:43

And how long were the dinosaurs around?

Mark Witton: 29:45

So dinosaurs first appear about two thirty million years ago, and of course the peak of their diversity in one sense is then in the Mesozoic era, so times like the Jurassic and the Cretaceous. So we're talking here sort of, you know, a 150,000,000 ago, that's when the Jurassic ends. 66,000,000 ago, that's when the big extinction occurs, the asteroid hits the coast of Mexico and wipes out all the non bird dinosaurs along with a bunch of other animals as well. So things like the flying reptiles, the marine many marine reptiles, not all marine reptiles, but many marine reptiles go extinct at that point. The ammonites, the famous ammonites, they also pretty much disappear around that time.

Mark Witton: 30:25

So dinosaurs have been they they were, in some respects, that they're most diverse in the Mesozoic, but this isn't to say that modern dinosaurs are are are just sort of, you know, trudging along. There's 10,000 species of dinosaurs still around on the planet today, so they're doing just fine. You know, dinosaurs are are more diverse than than we are as mammals. So, while we're talking about the diversity of dinosaurs in the Mesozoic, what we're really thinking of is their sort of their different shapes and sizes. They were more diverse in that respect in the Mesozoic, but today we certainly know of more we certainly identified more modern bird species than we have dinosaurs in the fossil record.

Moira: 31:04

And we're just the new kids on the block.

Mark Witton: 31:07

Absolutely, yep.

Moira: 31:09

Thank you, Doctor. Witton. I hope you come back and see us again. I just love talking with you.

Mark Witton: 31:14

Yeah. I'm I'm always happy to to talk about dinosaurs. It's, you know, I I guess I guess that's why I do what I do. Right? It's just that, you know, if if I was sensible, I'd just go and, you know, get a get a proper job in a bank or something.

Mark Witton: 31:25

But, yeah, it's decided I have to devote my life to writing and talking about dinosaurs.

Moira: 31:28

My guest today is vertebrate paleontologist, doctor Mark Witton. His book is Spinosaur Tales, the Biology and Ecology of the Spinosaur. It's published by Bloomsbury Publishing. I'm Moira Gunn. You're listening to Tech Nation.

Moira: 31:45

It's published by Bloomsbury Publishing. For Tech Nation, I'm Moira Gunn. That was so great. Oh, I'm so glad we did it.

Mark Witton: 31:53

We did it.

Moira: 31:54

We did it. Now don't hang up because we have to upload the