Archive: Feathered Dinosaurs

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1:49Earn rewards when shopping, dining out, and fueling up. And all of that becomes fuel savings when you're at the pump. Find the Shell app on your phone and enjoy life with more. Your nearest Shell station is less than five miles away. Hello. In the latest edition of In Our Time, my guests and I discussed the first dinosaur to ever be given a scientific name, Megalosaurus. It was formally described by the geologist William Buckland in 1824, before we actually had the word dinosaur. During the 19th century, Megalosaurus became part of a shift in how people understood the history of our planet and life on it. But over the last century, there's been another shift in what we know about dinosaurs.

2:37Feathers. In this archive episode of In Our Time, Melvin and his guests unpacked the discovery of fossils, establishing that at least some dinosaurs were feathered. If you're anything like me, it'll completely change how you think about prehistoric life and how you look at birds today. I hope you enjoy listening. Hello. Until 20 years ago, dinosaurs were widely assumed to be large, lumpen lizards that became extinct millions of years ago. Discoveries widely assumed to be large, lumpen lizards that became extinct millions of years ago. Discoveries in China have since shown dramatically that many were fast and feathered, and some survived the great extinctions and are the ancestors of our modern birds.

3:16The recently discovered Chinese fossils of feathered dinosaurs are so well preserved, scientists can even work out the feathers' colour and where they were found on the dinosaurs' bodies, and theorise about their use for displays, insulation, and in some cases, perhaps, flight. Even the large Tyrannosaurus may have had downy feathers, and it appears that the small Velociraptors had long quill-like feathers arranged on arms that look like wings. With me to discuss feathered dinosaurs are Mike Benton, Mike Benton, Professor of Vertebrate Paleontology at the University of Bristol, Steve Brussati, Reader and Chancellor's Fellow in Vertebrate Paleontology at the University of Edinburgh, and Maria McNamara, Senior Lecturer in Geology at University College Cork.

3:59Mike Benton, how did the idea become commonplace that dinosaurs were slow, heavy lizards? I think this is what many of us were brought up with. And I think those over the age of maybe 30 or 40, definitely. And we still commonly use the word dinosaur to mean a sort of failure or something that's lumbering and hopeless. So we were brought up with books that show large, grey-coloured, often reptilian creatures. And the assumption is they'd be kind of dragging their tails and crawling around in the swamps and that fitted an idea that they're extinct and they're long forgotten and that they'd had their day and they couldn't survive. But as you said in the introduction that's massively changed as a result of new discoveries.

4:43Because they lived for... If we the human species lived as long as they lived for, if we, the human species lives as long as they did, we would be lucky, wouldn't we? Well, yes, indeed. Or not. I think thinking of the time they were on the earth, they clearly were massively successful. And so the new discoveries help us to understand why. And why did it catch on so firmly in the imagination of the general public, and particularly the younger general public? Why the largeness and the lumberingness and the sleepy slowness? And the power of the quadriplegian. Why do you think it caught on so much? I think people liked the idea because it was something like a fictional world. It was something like dragons and monsters.

5:22And we all want to believe in those kinds of things. And there they were. And they were legitimated because they were real. You could go to the Natural History Museum and see these great skeletons. And I think also for the scientists, the fact that many of them, like Diplodocus and Brontosaurus, were absolutely huge. So they would have weighed maybe 50 tonnes compared to the biggest of elephants weighing five tonnes. You have to think, how could you have an elephant of that size? Therefore, the world must have been massively different. They must have been living in a different way, maybe living in slow motion. And then kids have always loved it, of course, because of the imagination and sort of

6:02thinking of heroes and other worlds where they might have liked to live. Given the interest at Kindle once it got started, it took a long time to start. Thomas Huxley, Darwin's bulldog, he was called in the 19th century, was someone who dug into the theory, into the apostle theory of that as early as anybody else round about. Yes, and so Huxley got it right. Around 1860, 1870, he was studying some of the early dinosaurs, particularly the two-legged ones that we generally call, the meat eaters that we generally call theropods. And he noticed, and he looked also at Archaeopteryx, which was the oldest bird and still is reckoned to be the most primitive bird. They had just been discovered in Germany. And he noticed that apart

6:51from its feathers, Archaeopteryx had the skeleton of a little dinosaur. And so he had a vision of them as a bit more active. And he was pretty clear then, so long ago, that birds and dinosaurs were close relatives. What material did he have to work from? So there wasn't a great deal at that time. There were a number of isolated large bones that had been collected in England from the 1820s onwards. No complete skeletons, really. And then I think he was very influenced by discoveries in South Germany around 1860 where they found skeletons of a small dinosaur called Compsognathus and of Archaeopteryx and of course there was a creature the size of a pigeon with its wings outspread with clear feathers along the

7:38wings and yet he could see that it had a reptilian skeleton. How was Huxley's news received? Well, I think he pushed it because he was, as you said, Darwin's bulldog. He very clearly saw this as evidence of evolution. Here was the sort of missing link between reptile and bird. And so he was enthusiastic, and I think a lot of others at the time. But then very oddly, we sort of reversed for about 100 years, really, from 1870 to about 1970. And it was during that time that more complete giant skeletons were coming out of the United States and Mongolia and other parts of the world. And I'm not quite sure why people stepped back from Huxley's view. Maybe it was just the sheer size and numbers of these giant dinosaurs

8:30that they thought, you know, the world was truly different. Steve Brussetti, before we go further, can you give us a few astonishing facts about the lifetime and what they did and why they were there so long and how most of them were extinguished so quickly. Well, I'll try to do the story of dinosaur evolution in 30 seconds or so. No, no, you go on, man. Don't rush. Really don't rush. I'll wave my hands if you're going too long. Well, it was a long time they lived. So the first dinosaurs show up about 230 or 240 million years ago. And this is when the Earth is recovering from the worst extinction that ever happened, this extinction at the end of the Permian period, when maybe 95% of all things went extinct. So you

9:12had this new world after the extinction, open playing field, and that's when dinosaurs entered the scene, along with a lot of other groups like mammals and turtles. And so then these first dinosaurs, they got their start slowly. They didn't take off all of a sudden. They didn't spread around the world like an infectious virus or something like that. They took their time, about 50 million years it took for them to slowly diversify until another extinction wiped out a lot of their early rivals. And then in the Jurassic period, dinosaurs spread around the world. You got enormous dinosaurs evolving, the big colossal long-necked dinosaurs, the bus-sized meat-eaters. They were living on all continents. The continents were one at that time, Pangea, the single land

9:55mass, but it was breaking up gradually. The dinosaurs were along for the ride, and they continued to evolve until the end of the Cretaceous period, 66 million years ago when this six-mile-wide asteroid fell out of the sky. Things changed very quickly. The T-Rexes and Triceratopses and Brontosauruses, they couldn't cope, but some birds could, and now we have birds still with us. We should print that out and hang it on the wall of most classrooms. Now, what are the significant divisions in the dinosaur mass? There's a lot of dinosaurs now. There's over 1,500 species that have been found, and people are finding new ones all the time. It's really an incredible moment that we're all in right now

10:40because somewhere around the world right now, somebody's finding a new species of dinosaur on average about once a week. So we're getting about 50 new species a year. This is the golden age, and they're coming from everywhere. China, of course, as we'll talk about, but every continent dinosaurs are found on. And we're even finding them up in Scotland. So there are so many species. There are lots of classification schemes. These are the things that a lot of young kids memorize and a lot of people like to argue about. But really, to me, the most important divisions of dinosaurs, there's three main groups. There's the long-necked ones like Brontosaurus. We call those the sauropod dinosaurs. There are the plant-eaters with beaks. These are what we call the Ornithischian dinosaurs, so things like Triceratops and Stegosaurus, and then there's the theropod dinosaurs, the meat-eaters.

11:26Is there one group in particular that the feathered dinosaurs enter into? It's this third group, the theropod dinosaurs. So birds come from theropod dinosaurs. They evolved from theropods the same way humans evolved from apes. So birds are theropod dinosaurs. What distinguished theropod dinosaurs to make them carry the feathers? Well, this is the big question. And this is what we're learning so much about, you know, in China over the last couple of decades. It looks like feathers go way back to the earliest theropods. And then it looks like one group of these theropods, over time, gradually got small, changed their skeleton, evolved feathers, changed those feathers, and turned into birds. So some theropods, like T. rex, for instance, these were enormous, plodding meat-eaters.

12:16Other ones had crests and sails on their backs. Some were tiny. There were lots of variety of these theropods, but birds emerged from that great diversity. Over 50 million years. Yes. It was a long process. A bird didn't just evolve one day. A T-Rex didn't mutate into a chicken. That's not how evolution works. But it was a long process of gradual change. And at the end of that, a bird emerged, a small feathered winged flying dinosaur. Maria McNamara, we're talking about feathers. What do our listeners to understand by feathers? OK, so feathers are really remarkable, excuse me, integumentary structures. So they're derived from our integument or our skin. And we know that by studying the development of feathers in chick embryos,

13:07we can actually work out where they come from. So we know that during growth of a chick that as the skin is developing, you form a little thickened region in the outermost part of your skin. This thickened region starts to project inwards, forms a follicle. And the cells lining that follicle, they're from the dermis, the lower part of the skin. They die off and they start to form the interior part of the feather. At the same time that this is happening, some cells start to project outwards from the skin to form a hollow shaft. And this is basically the fundamental structure of a feather it's a hollow tube but when you look at modern birds today feathers are actually much more complex than that

13:51usually they're actually the most complex structures derived from the skin in vertebrates animals with backbones so a typical feather flight feather in a crow or a jackdaw, it actually has several levels of branching. So that central shaft or tube, which would be familiar to readers or listeners as the quill part of the feather, that branches into smaller structures called barbs. In turn, those barbs have little branches called barbules, and these barbules are in turn differentiated at their tips into little hooklets that can zip together to form a nice closed vein. One thing that interests me, picking up from what Steve said, is that there doesn't seem to have been inside this long range of life that the dinosaurs had

14:40any development or evolution of feathers. There were feathers at the beginning, there were feathers in the middle, there were feathers at the end. Is that right? Did they just pop up for a reason we as yet don't know? Okay, so when you look across the dinosaur tree, when you look across the theropods and also the Ornithischian dinosaurs, we can see evidence of feathers at different developmental stages, different evolutionary stages. So we see a spectrum of fossil feathers that go right from the very complex feathers that are anatomically modern, they look identical to what we have in birds today, right back to clumps of filaments and even further back to just simple filaments that for all intents and purposes, look like hairs.

15:26So there was evolution. Yes, we can track the evolution. What we see in the developing chick, as a feather develops in an embryo, we can see these different stages of morphological development in fossils. Mike talked about the hundred years backward step. It was given a huge acceleration forward with the discovery of this great field of fossils, miles, kilometres of fossils in northeast China which seems to have changed everything in your area of study. Can you tell listeners how that happened? So in the early mid 1990s there came the initial report was of a new dinosaur called Sinosauropteryx. And the discovery of this specimen absolutely electrified the world of paleontology because this dinosaur preserved feathers.

16:21So these were very controversial, of course, because the feathers in Sinus roptrix, they're very, very short. They're only about 10 millimetres long and they don't really look like the complex feathers we see in modern birds. They look like simple hair like filaments. So the initial reports, you know, which gained huge attention among paleontologists and the media alike because it was the first direct evidence for a link between birds and dinosaurs. It was the first dinosaur bearing feathers. These were actually very controversial because you had some paleontologists who reinterpreted those feathers as other structures, as just fibres from the skin. Can you give us some idea of the range of material available and the vast

17:07as it were fossil fields there are in North East China? Well I mean you know you have most of the fossils that we're talking about they come from two main fossil biotas. The Jehol biota which is early Cretaceous in age, and the slightly younger Jurassic Dauhugo biota. And so I've done fieldwork at some of these localities and unfortunately there's been so much activity and the local farmers are so eager to recover fossils that some of these sites are now very heavily protected by CCTV. So as a paleontologist... But what do you get out of it? What do you get out of it? Oh, I mean, well, in terms of some taxa, you can recover thousands of specimens. So there's a primitive bird called Confucius

17:55Ornus, which is known from thousands of specimens now. But you referred early on, Mike, to the thing coming out of German, I think it was usually, which is about a kilometre or so long. This is hundreds of kilometres long. This changed the game. This was like the sort of meteor into the world, wasn't it? The Chinese meteor came and changed utterly. It did, because that's right. And I remember people would view Archaeopteryx, the German one, as something really unique, and people talked about it as the most valuable fossil in the world, worth a million or ten million dollars. And then over the years, a number of additional specimens were found. Each raised a great deal of excitement. There are now about 12.

18:37As Maria said, from China, there are thousands of individual fossils of the same quality or better. And some of the slabs, you'd swear they make them up, but they don't. What is it that preserves them so well in northeast China and in that particular part of Germany? And occasionally, as we're told, in Scotland. But let's stick with China, because that's a big resource. The Chinese ones, they occur in, as Maria said, in numerous localities over maybe 1,000 kilometres or more. Wow. And these are just great series of lakes and they're preserved mainly in the fine sediments that would be settling down through the water in the lakes. And there's a great deal of volcanic activity going on so people think that has something to do

19:20with the extraordinary preservation that the ash is kind of settling and that has a way of sealing them in. What does the ash not let in that's good not to have let in? It prevents decay. The key thing is, normally when an animal dies, and if it falls into a lake or just lies on the surface, within a matter of days, the soft tissue will go, either to decay or scavengers. So if you can keep the decay bacteria and the scavenging insects and other creatures out, then you're in business. There's this man called John Ostrom who comes onto the scene. Can you tell us about him? Give us his dates, please, and tell us about him. Yes, so John Ostrom was a great paleontologist in the United States. He was at Yale University.

20:03In 1963, he was excavating dinosaurs in the United States. He was at Yale University in 1963. He was excavating dinosaurs in the Midwest. He found this remarkable little theropod called Deinonychus. Some people may have seen pictures of this. It's often shown pirouetting on one foot, leaping at its prey with a great slashing flick knife type of claw on its hind foot and sort of leaping and slashing the side of the prey. And he speculated this was a fast-moving dinosaur. And there was a critical point in 1969 when Ostrom published on this dinosaur with illustrations showing its extraordinarily slender body that it must have balanced in a remarkable way to be able to achieve these movements. And this was not a lumbering, old-fashioned kind of dinosaur that we'd been used to. And he noted a second thing. He repeated what Huxley had done exactly 100 years before.

20:55And he said, this thing is Archaeopteryx. This is a bird, except we don't see the feathers. But he speculated it would have had feathers. And then soon after, I was at a meeting of the American Society of Vertebrate Paleontology in New York in 1994. Ostrom was there as then quite an old man. The Chinese turned up, as Maria said, with these photographs of Sinoceroptrix. This was before it was published. They're showing them around, he was vindicated. just for quick questions. Hand it a whole task like turning a folder or scattered notes into a report and it does the work and hands back something finished that you can open and edit. Claude can now draft a doc or deck right in front of you and Claude design now lives right inside Claude. Describe the website or

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23:28Craving something sweet after every meal? Hungry again an hour after you eat? Weight won't budge no matter how disciplined you are? These are all signs that your body isn't producing enough GLP-1, the hormone that keeps you full and supports weight loss. The good news? Bioma GLP-1 Booster helps you increase its natural production. So you can quiet the food noise and enjoy smoother weight management when following a healthy lifestyle. Head to bioma.health slash GLP-1 and use code podcast to get 15% off. Can you give us, can you survey the field, Steve, about which of these dinosaurs were feathered and in the mass? Can you pick them out to give the listeners some idea where we are? Yeah, these Chinese dinosaurs, they really have been a game changer.

24:11And I think we're so used to hyperbole about dinosaurs. You know, you see a new dinosaur in the news and it's, you know, a predator the size of a bus or a dinosaur the size of a plane. And sometimes we can overdo it a little bit. But with these Chinese feathered dinosaurs, bus or a dinosaur the size of a plane. And sometimes we can overdo it a little bit. But with these Chinese feathered dinosaurs, they are definitively the most important fossils that have been found, at least in my lifetime. And they're so important because the preservation is great. You get, you know, this volcanic activity helped preserve those feathers. But also because there are so many dinosaurs, there are different species that are found with feathers,

24:51and these things really span the dinosaur family tree. So you can map out which species have feathers on the family tree, and you can see how those feathers change. And that tells the story of feather evolution, but even more broadly, the story of bird evolution, how a dinosaur turned into a bird. And so what we know now is pretty much any theropod dinosaur, any member of that great group of meat eaters, that is found in China in these deposits has feathers, some kind of feathers, even tyrannosaurs. There's a nine-meter-long tyrannosaur called Eutyrannus there that is found covered in a coat of these very simple hair-like feathers. And then there are lots of other small theropods with simple feathers like that.

25:28There are some plant-eating dinosaurs there with simple feathers like that. So to me, that indicates, because you have all these meat-eaters and plant-eaters that have these feathers, that probably feathers go all the way back to the base of dinosaurs. Probably all dinosaurs had some type of feather. But then this one group of theropods, this derived group of theropods, of manoraptoran theropods, they started to change those simple feathers. For most dinosaurs, that coat of hairy stuff was enough. But these manoraptorans started to lengthen those feathers. The feathers started to branch out. They started to flatten out. They started to flatten out. They started to evolve the barbs and the barbules that Maria was talking about. These dinosaurs started

26:09to line up some of those feathers on their arms. Wings formed. These dinosaurs were getting smaller and it was that group where all of the exciting change was happening and it was that group that led to birds. And getting smaller was very important. And also it changed the idea of the great horrible lumberer beast. Could move fast, could be swift, could be... It changed the nature of life in the dinosaur world at the perception of it. It did. And it changed the perception of dinosaurs really for all of us. And even though I don't think I'm that old, but I remember when I was in school in the 90s, we still were taught that. All of our books in school had these lumbering, plodding, really stupid-looking, green-scally dinosaurs hanging out in swamps. But I remember in 1997, when the

26:59first feather dinosaur, Cynosauropteryx, was officially named and described. I remember seeing that in the newspaper growing up in the middle of America, Ottawa, Illinois, the little town where I'm from in the cornfields. It was in our newspaper. I remember seeing that, and it blew my mind because it was such a different image of dinosaurs. Maria, can we come back to you? Can we talk about the differences between hairs and scales and feathers and how that works in the process of evolution to the feathered dinosaurs? Okay, so feathers and hair, they have a lot of common characteristics. They each grow from a follicle. That follicle is lined by cells from the dermis, the lower part of the skin.

27:46They're both derived ultimately from the epidermis, the outer part of the skin. But a major difference between feathers and hair is that feathers are hollow and hairs are not. Hairs have a solid cortex. And they're both known to develop from this structure, this thickened epidermis called a placode during development. And, you know, for years, until recently, there was no evidence for these placodes, this developmental structure in reptile skin. So it was thought that feathers and hairs actually were represented two independent evolutionary events, that these two different groups, birds or, you know or dinosaurs and mammals, had each independently evolved these epidermal outgrowths. But then, very exciting,

28:32two years ago, a group based in the States uncovered some biochemical evidence for certain enzymes, genetic precursors for placodes in reptile scales. And then in 2016, so last year, a study looking at Evo Devo of reptile scales actually found at a very early stage of development placodes. So you have scales, hairs and feathers all developing in the embryo from the same, effectively the same structure. So the inference is they have a common evolutionary origin. Ultimately, hairs, scales and feathers evolved from the same primitive structure. And what does that lead you to? Well, so that implies that, you know, the hairs and the feathers we're seeing in these dinosaurs and mammals, they have a common origin.

29:26So, you know, really, when we're trying to find, a lot of the work that we do is, we try and understand the deep origins of these structures. The wonderful feathers that we see in primitive birds and feathered dinosaurs, they tell us about the end of the story when things are already becoming quite complex. But I think actually a lot of the interesting part of the story will lie in much older fossils. So trying to uncover the very early steps of evolution of these integumentary outgrowths. Mike Benton, can we go back to the Archaeopteryx, this supposed first bird? As I understand it, there was a gap in knowing what was going on for almost 50 million years. And various theories came up that said evolution didn't happen here.

30:15Now and then some event happened and pushed it forward, some horrible monster, or hopeful monster, sorry, hopeful monster, that was the phrase, turned up and pushed the whole thing forward. Let's get over those 50 million years and then get on with it. That was more or less what was going on, but then it changed. Yes, you're right. Archaeopteryx changed that. It did, and the new discoveries did, because Archaeopteryx was seen as a missing link. People use that term. It doesn't really have any precise definition, but we sort of know what they mean between reptile and and bird and it did stand on its own because you had all the dinosaurs as we've been talking about uh flesh-eating dinosaurs and others without feathers um you have archaeopteryx

30:56and then there was a long gap uh of maybe 50 or 60 million years before further fossil birds and people said oh well birds don't preserve very well as fossils because they're delicate and small and they'll tend to disappear, they'll rot away, they won't be found. And so this was then read by evolutionary theorists to say, how did this happen? How do you make a transition from crocodile to bird? They're close living relatives. And so there were some ideas of macro mutations and hopeful monsters, as you say, around the 1930s, 1940s. And some people thought, yes, the only way you can make such an enormous transition is to have some extraordinary genetic revolution, something that we don't know about in current genetics. And that made people very uncomfortable because it sounds like a breakdown of normal

31:52natural processes. And the risk, of course, of a kind of hopeful monster is it'll be a failure. This is like such a huge mutation that the chances of it working. And it's still an argument that confuses people who are troubled with evolution today. They'll say, oh, you look at a bird, you look at a pigeon, and it's so beautifully adapted. It's got lightweight skeleton, it's got a very high metabolic rate, it's got feathers, it's got wings. The adaptation to fly, and we think of human endeavour to make an aeroplane fly. But the point is, then all of these fossils since the 1990s have filled these gaps both before and after. And they show us that half a bird works. You don't actually have to be a complete pigeon.

32:37You can be a flyer with primitive feathers and limited wings. Do you want to help us out in this 50 million year gap, Steve? Yeah, this is a subject I love to talk about because a lot of my PhD work was on this and I spent all this time, like, you know, Mike and Maria, very privileged to be able to go to China and study a lot of these new fossils. And really what they do is when you map these fossils out on the dinosaur family tree, it tells you that story of evolution and you can kind of see evolution happening like something of a, you know, running film in action. And what it shows is, you know, this wasn't a hopeful monster situation. A bird was something that emerged very gradually from

33:15this one group of dinosaurs over time as piece by piece, it evolved feature by feature of modern birds. I mean, modern birds have a very distinctive body plan. You know, they're small, they have feathers, they have wings, they're lightweight, they have wishbones, they could fold their arms against their body, hundreds of things that make birds unique among any other living animals. But these fossils show that those things evolved one by one in dinosaurs over time, and usually for reasons that had nothing to do with flight. They were being evolved for other things. So, you know, the wishbone is instrumental for how birds fly today. It's a spring that stores energy in the wings. But that first turns up in small meat-eating dinosaurs that were probably hunting,

33:58and so they were, you know, reinforcing their shoulder girdle. So the same way that whoever invented the propeller, I don't know who that person is, but they would have had no idea. The Wright brothers would have put it on a plane. This is what evolution was doing. It was changing features of these dinosaurs, and later on, those things would work together to allow this new small type of dinosaur to fly. What was the purpose of the feathers? This is such an interesting area of research. A lot of debate now. What fundamentally we know is that these fossils tell us that the first feathers were simple. The first feathers were these downy kind of hair looking feathers. They were present in dinosaurs like Tyrannosaurs and some of the plant eaters that definitely weren't flying.

34:42Those animals couldn't fly. They were too big. And those feathers were just like hair. I mean, I can't fly with my thinning weren't flying. Those animals couldn't fly. They were too big. And those feathers were just like hair. I mean, I can't fly with my thinning head of hair, but I can't fly. So feathers first evolved for something else, probably for insulation. It makes sense. We don't know for sure. But, you know, these dinosaurs were active and energetic. They needed to retain their body heat. So probably the first feathers evolved for insulation. But then that one group of small meat-eating dinosaurs changed their feathers, turned their feathers into things that could form wings. But now we see, amazingly, this has emerged over the last few years, that the first dinosaurs

35:16with wings couldn't fly either. They were too big. Their wings were too small. So it looks like even wings did not evolve for flight. Maybe they evolved as some kind of display billboard on the arms, you know, to attract mates or intimidate rivals. Animals, including birds today, are always using their feathers for display purposes. So I think what we're seeing is a lot of feather evolution had nothing to do with flight and flight only came later. Maria, because of the plethora of stuff coming from China mostly and from other places and because of the massive development in technology, you can even begin to tell what colour, the colours that these creatures had. Can you just tell us a bit about that please?

36:00Yeah, sure. So, you know, when you look at the feathers of modern birds and if you crack them open and put them under a powerful electron microscope, you'll see these tiny little microscopic structures. They can look like tiny little balls or tiny little sausages. And these are granules of the pigment melanin. And melanin is just one of the many pigments which modern birds have in their feathers. And what's really remarkable is over the last 10 years or so, we've come to realise that these, you know, this evidence of melanin pigment can actually survive in fossil feathers. So, you know, several ancient birds and feathered dinosaurs have been studied by researchers. And we've been looking at the record of colour preserved in their feathers using these melanin granules.

36:49And what's really remarkable about these melanin granules, or melanosomes as they're called, is that their shape actually varies. And these different shaped melanosomes can generate different colours. So the sausage-shaped melanosomes produce blacks and browns. The spherical ball-shaped melanosomes produce reddish, foxy ginger colours. And so, for instance, Sinosauropteryx, that first dinosaur that I mentioned that was reported to have feathers, Mike and some colleagues were involved in a study where they led a study where they showed that Sinosauropteryrix, that those primitive hair like structures, they contain melanosomes. So they're very definitely feathers. They're not just skin fibres.

37:35But, you know, what was really exciting was they showed that those melanosomes in sinusoroptrix are shaped like little balls. So sinusoroptrix was a ginger dinosaur. Can I come to... So you discovered the ginger dinosaur, didn't I? Indeed, yes. Well, that's something to do, isn't it? I mean, most of us don't get anywhere near that. Can you tell us about Maniraptorans? How do they add to the emerging picture? We're still on wings, aren't we? Are we getting towards wings? Yes, we are indeed. And it seems that the two things were happening, as we've mentioned, that mostly in the theropod dinosaurs, they had a trend to large size and shortening the arms. And we think of T-Rex as a kind of end of the story. And every child will tell you that

38:21the arms are so short it couldn't even reach its mouth. But in the Manoraptorans, the name means hand hunter. Their arms were extending, and this is what Ostrom noticed in Deinonychus, which is a Manoraptoran. And we now know that the extension of the arm was so that it would carry feathers, but the shrinking of size was happening at exactly the same time. So there's miniaturization and extension of the arms and as Steve said, these were not flying, or they may have been able to use them at times for gliding just by spreading them out, but almost certainly they'd be using them for other purposes and the discovery of the ginger color, it wasn't just ginger in Sinosauropteryx, it is a Maniraptor and it is

39:02a dinosaur. The tail was striped like a barber's pole. So it was repeated regular stripes of ginger and white, ginger and white, ginger and white. And the rest of the body was covered with sort of ginger color over the back and maybe pale on the belly and various patterns over the face. And so we were thinking, why would it have a stripy tail? Could this be camouflage? You think of a tiger or a zebra. No, because it's only the tail. Why camouflage your tail but not the rest of your body? Therefore, display. And as Steve mentioned, this actually shifts behavioural functions, bird-like behaviour, down. And so we imagine these little dinosaurs hopping around, waving their tails and saying, look at me. Can I come to you then, Steve? As you were researching backwards,

39:51what does your present study of birds tell us about where they came from? Well, we now know, you know, unequivocally, nobody really argues this anymore among paleontologists, that birds came from dinosaurs. And what that means, it means a lot of things. But one thing I would just like to highlight there is that it helps us. This realization helps us understand dinosaurs better. It helps us understand T. rex and Triceratops and Brontosaurus better because we know that they have living descendants. And so this helps us to better understand how these ancient dinosaurs, which oftentimes are so out of scale to anything that's around today, it helps us to at least better envision what they were like as real animals,

40:36as things that had to grow and feed and move. And we now recognize that, by and large, dinosaurs, whether it's T. rex or these enormous creatures like Brontosaurus, they were much more bird-like in their behaviors than lizards or crocodiles. So all of this has led to a bit of a new picture of what dinosaurs were like, and I think it's brought dinosaurs to life in a way that we could have never imagined before these fossils were found. Maria, can you explain the uneven distribution of feathers among the dinosaurs? Okay, so, you know, one thing that has emerged in recent years is a picture of how birds acquired feathers and, you know, what we would conventionally consider wings. And what we now understand is that there wasn't a progressive

41:25change whereby feathers gradually became more complex over time. It's actually a lot more complicated than that. Feathers and wings, they evolved in a really piecemeal fashion. So, for instance, you know, you have some early feather dinosaurs like Anchiornis which has beautiful veins, so complex feathers on the forelimbs and the hindlimbs. But then you look at some younger fossils like Sinosauropteryx and it doesn't have feathers that are this complex at all. So what's happening with feather evolution, the evolution of wings, it's more like a mosaic. Different features, so the hindlimbs and the forelimbs and the tail, they're all almost evolving independently. And these changes towards a bird-like appearance,

42:12they're happening in kind of spurts in different dinosaurs. Mike, Ben, can I come back to you? When, in this 50 million year span, when did they actually start to have proper wings and fly so we would recognize them among the birds today? Yes, I think that's Archaeopteryx. So the interesting thing is there has been stability. When did he come along? So that's about 150 million years ago at the end of the Jurassic. And so we have 50 million years leading up to that. So just to make it really clear, when I was taught and when I started to teach as well, Archaeopteryx stood there as the possessor of maybe 50 unique bird characters. And now almost all of those features have gone back, as Steve was saying, the wishbone, the hollow bones, the small body size, the development of wings in manoraptorans.

43:00So virtually all of these uniquely bird characters have sort of gone back down the evolutionary tree being acquired piecemeal and so Archaeopteryx is still characterised and we would say birds as well by the ability to fly in a powered way that means beating the wings up and down with the complex of muscles and using that wing beat to keep aloft So let's nail it the millions are rather baffling me when, about when, within a couple of million years muscles and using that wing beat to keep aloft. So let's nail it. The millions are rather baffling me. About when? Within a couple of million years. So the process would have begun over 200 million years ago with the origin of dinosaurs and then at 150 million you have

43:37Archaeopteryx with proper muscular wing beats and powered flight and the first bird as most people would say and then you carry on in going through into further Chinese deposits and good record of birds right through to 66 million years ago the extinction of the dinosaurs the extinction of a lot of these early bird types and then the massive explosion of modern birds and 10,000 species of birds today. How revolutionary have these discoveries been, these last few years' discoveries? To me, these are the revolution, in my lifetime at least. And I think they have changed our perception of dinosaurs. I think they're starting to change the public perception of dinosaurs. Of course, the public perception takes some time to catch up sometimes with the scientific way of seeing things. But it's hard to really overstate their importance.

44:32And they are beautiful fossils. A lot of these look like they should be in art museums. They are a thrill to study. And farmers across Liaoning province in China are finding these every day. There are farmers out right now, I'm sure, that are finding more of these fossils. So this revolution is not ended. It is still ongoing. And who knows what the next big find is going to be, but it'll probably happen in the next few weeks. So everybody should keep their eyes peeled to the news. Peeled on Northeast China and forget about what's happening in Beijing or anywhere else. Mike, I'll come back to you for a moment. Why did they survive when none of the other dinosaurs did? And that's a very difficult question,

45:16because, in fact, very many of the birds did die out at the same time as the dinosaurs, the heavier dinosaurs did, at 66 million years ago. And so why a number of very weird-looking duck-like creatures, which were the precursors of the modern birds, survived through that crisis, we don't know. They're small, but that doesn't save them from everything. They had high metabolic rates, so a big need for food. Because people used to say, oh, well, turtles and crocodiles survive. They just burrow into a hole and just kind of sleep it off and crawl out a week later and the meteorite is gone and everything is gone. But no, frankly, that is a mystery because the lifestyle of the birds that survived would have been almost certainly similar to that of the primitive forms that went extinct.

46:00So that is still a mystery that may not be solved. Maria, what's the most pressing question you have that you want answered by these fossils that are coming through every day according to Steve? I mean, as we speak, it's probably mountainous. Anyway, never mind. Okay, so there are two main, there are two obvious areas that we need to be focusing on in terms of understanding feather origins and feather evolution. So, for instance, we now know that two major groups of dinosaurs, the theropods and the ornithischians, had feathers. And as far as we're currently aware, the third major group of dinosaurs, the sauropods, didn't. So, and this is a major thorn in the side of people like myself and Mike, you know,

46:46and Steve, we all believe that dinosaurs evolved very, that feathers evolved at the base of dinosaurs. We need to look for feathers in sauropods and to really understand, we need to go way back into groups that are older than dinosaurs. Well, thank you very much, Maria McNamara, Mike Benton and Steve Brussati. Next week, we'll be discussing Guernica by Pablo Picasso, the painting and the events in 1937. Thank you very much for listening. And the In Our Time podcast gets some extra time now with a few minutes of bonus material from Melvin and his guests. Yes, that was very quick. I didn't realise you were so tight at the very end. I thought I had another half a minute. You have to sort of risk being rude, which is awful,

47:30but there's no other way. Maria, you didn't get on to the molecules and the survival of organic matter. No, no. But there we are. Because that's an important question that people have difficulty with. We'll see, Dan. Yes, yes. So the question is, and I'll pass it to Maria, which is people report DNA, people report red blood cells, they report't going to have a problem with that. But DNA and other biomolecules, proteins, tissues like feathers, which are made of the protein keratin, these molecules are very decay-prone, and they're not going to hang around over millions of years on geological timescales. So claims that these kinds of biomolecules can survive are very, very controversial. And a lot of them are based on

48:28evidence from techniques that paleontologists, quite frankly, don't use. So we don't know how to test the... But chemically, what about melanin? I mean, what's the thing about melanin? Okay, so, you know, melanin, we all know that there's really good and robust chemical evidence for survival of the melanin biomolecule in some of these chinese fossils um so people have used various different techniques you know there's two or three key techniques that you can use to show that the molecule is surviving as well as the actual physical granules themselves so they're not as some people claim that they're not decay bacteria basically you have these physical granules themselves. So they're not, as some people claim, that they're not decay bacteria.

49:06Basically, you have these little granules and they look like melanin granules and they contain melanin. The most plausible interpretation is that they are melanin granules. They look like a duck and walk like a duck. Then it's got to be a duck. Exactly. But survival of melanin, you know, it's not too surprising because it's a really tough molecule. You throw acids at it, you throw alkalis at it, and it doesn't degrade. The only thing that degrades melanin is really strong concentrations of peroxide. You've got to really oxidise it really heavily to, you know, destroy it. So that's why, you know, you look at a fossil feather in a dinosaur, the feather is preserved because of the melanin, you know, destroy it. So that's why, you know, you look at a fossil feather in a dinosaur, the feather is preserved because of the melanin,

49:47you know, and this is another big question. Well, if that's the case, where's the keratin gone? Is there any evidence for keratin survival? So this is a question that some of us are working on now. You know, can we find any traces of keratin associated with the feathers? But keratin is more decay prone. It's going to be harder to find and you've got to have better evidence. There you are, another program people are trying to bring. I did give you the error to a massive few more fossils. That's right. What did you not say you would like to have said, Steve? I'll just put out a pitch. We all teach and we all have a lot of students that are, you know, fascinated with this stuff. And there's so many opportunities,

50:27I think, for the next generation. There's some big mysteries still to solve. So I think, you know, for anybody who's listening out there who's kind of a young, budding paleontologist or thinking of studying this stuff, whether you're back home in, you know, the Midwest U.S. or up in Scotland or in China, indeed, wherever, somebody needs to go out and find a feathered sauropod. That's going to be a big deal. Somebody needs to find some older fossil feathers. Everything we have with these feathered dinosaurs is either Jurassic or Cretaceous in age. And so a lot of the big moments and evolution of dinosaur feathers and in the early part of the origin of birds, we're not really recording it in the fossil record.

51:03We're seeing signs of it in these Jurassic and Cretaceous rocks, but a lot of it was probably actually happening earlier. So if somebody can find some of these sites that preserve feathers, and it's hard to do, if it was easy, people would have found them. So you need a bit of luck, but that would be a big game changer. And then the big question for me, or one of the big questions, is how did flight actually evolve? I mean, we know that these dinosaurs are changing. They're getting smaller. They're changing their skeletons. They're developing feathers. They're turning their feathers into wings. But how did evolution actually make that step to allow these things to start moving about competently in the air?

51:39And so that's going to require a lot more than just finding fossils. It's going to require a lot of interdisciplinary work, probably a lot of engineering style work that is a little bit beyond normal paleontology. So I think there's some great opportunities for future work. And another area that people haven't looked at at all is, and it's almost like the elephant in the room, you know, if dinosaurs are evolving feathers, you can't just have a feather sticking out of a scale. You have to have a very evolving feathers, you can't just have a feather sticking out of a scale. You have to have a very modified skin structure to actually hold those feathers, to be able to manipulate them, control their direction. So what we actually should be looking

52:14for as well is, you know, features of the skin that have co-evolved with the feathers to enable feathered dinosaurs to manipulate their feathers, to control them, because these are all characters that are really important for flight so we should be looking at also preservation of the skin in these feathered dinosaurs as well What about you Mike? I agree with her, I agree with him Nothing more to say If I did that the programme would end at about quarter past nine You're the man. He's the producer, just in time. Maria's got a train and we promise you'll get around. You've got a taxi. Yeah. Thank you for listening to this archive episode of In Our Time. Every Monday, I revisit one of more than 1,000 episodes in our archive.

53:01And on Thursdays, you'll still find brand new episodes of In Our Time. Listen first on BBC Sounds or wherever you get your BBC podcasts. This cultural life from BBC Radio 4. I will never go into anything so deep like that again. The world's leading artistic figures reveal their creative influences. Disobey, disagree, disavow. I'm John Wilson and my recent guests have included the sculptor Anish Kapoor, photographer Annie Leibovitz, the actor Kristen Scott Thomas... It has made me good at telling stories about people who have a secret suffering. ..and former children's laureate Frank Cottrell-Boyce. If art's got one function, it's to point to what's wonderful and say, look, this is your world, it's insane.

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