Over the Heads of Dinosaurs: Pterosaurs

good morning everyone and welcome to the 2016 Royal Tyrrell Museum speaker series today Don will discuss transition and evolution of vertebrates that between land dwelling and flying reptiles and his talk he will present an overview of pterosaurs flying reptiles that live during the age of dinosaurs so without further delay I present you dr. Don Henderson well my official title is curator of dinosaurs very good and bad I'm interested in an awful lot of different things and one of them is pterosaurs I feel they just don't get enough attention they're quite amazing but they are so rare and so fragile that we are views of them for the longest time have been rather poor with but the last 20 years things have really come along amazing new fossils and new ways to study them so that's what I want to to highlight well I say something about this picture here's good old overhyped celebrity Tyrannosaurus and in the back is the Tolkien pterosaur picture it's the Mesozoic the usually it's some vague sort of pterosaur things in the background these ones look an awful lot like Pteranodon quite a well-known one from North America but reflecting the general ignorance these two never saw each other they missed each other by fourteen million years so I thought this is a nice picture but it also highlights that the masses of an awful lot to learn so two paleo illustrators about pterosaurs so I want to cover how we discovered them their relationships highlight features of their Anatomy and the relationship to other artists or other extinct reptiles and then highlight some really exceptional fossil sites and the last thing I want to show you is a somewhat controversial idea I presented of five years ago some people liked it some people hated it it was great fun and I'll show you what it is later so in the paleo biz you hear a bit more about pterosaurs than most outsiders would and in August I was at the fifth meeting of the flukes our er conference series on but every three years and it started in 2001 and I was at the first one and it roams around the world and being hosted in different places and there's about 50 60 people there maybe about half of them specialize just on pterosaurs so there is still an active there's an active research group now and I think that reflects this last 20 years the improvement in our knowledge of them so pterosaurs are characterized by flight and it's powered flight and by powered flight I mean active flapping of the four limbs so things like flying frogs and flying snakes and flying squirrels are not actually flying they're gliding if we called it a powered flight you have to be actively using your fore limbs up and down to produce not just the lift to keep you in the air but to propel you forward and the most recent evolutionary innovation that was bats about 50 million years ago birds did it sooner at a hundred and fifty million years the pterosaurs hadn't mastered at least 230 million years ago so and that this reflecting the Terr old museum's backboned animals were just talking about backboned animals here but there's insects as well what vastly a number any other flying vertebrates but we'll stick with the pterosaurs today this is the very first pterosaur fossil record for what it was a flying extinct animal was from 1784 the quarry's where these things are found would be mined by the Romans for floor tiles these flat stones but and they must have seen the fossils but they never they didn't care or they didn't recognize them but finally in the late 18th centuries people recognized this is something special and it's such a good fossil you almost you couldn't want a better pterosaur fossil except if it had soft tissue and pigment lying on a nest but anyway this'll do so this bit of a jumble but everything's there which is really amazing so there's the skull and jaws and a really exceptional thing the eye socket the eye is absolutely huge and look how far back it is on the skull not much space for gray matter at the back there but they did manage for a good a long time everything about them is extremely slender and built for lightness if you look at the bones you can see they're all crushed in a bit pterosaurs took the idea of the bicycle frame construction to extreme so you think a bicycle frame it's hollow tubes all put together it's very strong and very light but it can't be compressed longitudinally it'll buckle and if but it's quite good to resist torsion and bending and so there's a neck and this kind of neck is same length as the trunk region and this kind also has a very tiny tail at the top there there's a whole left leg and because this thing's a bit of a mess there's the right foot down there but what's really distinctive about the pterosaurs is their forelimbs so here's the right forearm there's the hand and here's this exceptional wing finger it's the fourth finger it's got the same numbered standard number of bones but they've all been greatly elongated and right away even in the beginning of the 19th century people were thinking this must be supporting some sort of membrane to help them fly it was George Cuvier in in 1801 that first wrecking pup in the published description recognized that this is a flying reptile everybody else had different ideas but he was able to show that this is a reptile and it would have been flying and it was significant that the first flukes our meeting was in 2001 that was the 200th anniversary of the official description of it of a pterosaur and you'll notice the name on the top there on that slide is pterodactyl a lot of common name for them people will refer to these things as pterodactyl but the preferred name now is to call them pterosaur so as I mentioned pterosaurs recognized early on as being reptiles but a lot of people still insisted that they a flying reptile that's just a contradiction so there's this nice illustration from 1800 I took this from a publication from Kevin Padian and it's really nice he has this image someone drew the rest on the back of a letter you can see the handwriting on the through the paper so again trying to think of them as mammals this one simmering in 1817 was still arguing these things are some sort of mammal and he was restoring them like that like looking like a bat and then there was this Eduard Neumann I'm sure he's no relation to Aaron human restoring that some sort of marsupial this top point if this this thing creeps me out this looks weird but even as ladies 1843 people are still trying to argue that there they were mammals so there was a good stream of fossils from from that that site in Germany which I'll show you later but then in 1828 there was a outside of Germany except the expanding their range came this animal dimorphodon from from the south coast of England early middle jurassic and this is Mary Anning she was the famous person who was firmed the first as a school girl I guess she didn't go to school that much she was putting me about twelve her and her brother found the first ichthyosaurs the first please eeeh sores and then she found this first british pterosaur and the first terrorists are away from Germany and it's she's a very interesting character and there was the last ten years has been two biographies about her and it's kind of a sad story because she was shafted by her sex in the nineteenth century and sort of marginalized and died in poverty which is kind of sad but anyway she did a huge service divert paleo in the nineteenth century oh yeah that's her dog so here's the rest on early restoration so from 1828 you didn't get a published restoration until 1870 and it's actually pretty good there'd been a steady flow of pterosaurs fur melts from Germany as well so people had a nice idea and if you compare this illustration from what's that 140 years ago and we can come to a more modern one which I really like this painting this is by John Civic and this is from a book from 1991 called the illustrated encyclopedia of pterosaurs by Peter vellum Hofer and it's been referred to as a pterosaur Bible it's such a good book and it's so comprehensive it's only problem is that it's 30 years old the basic information is fine in this book some things have changed but there's been so much happened in the last 20 years that then there's only being two other terrorists or books in the last 20 years and when days came out a few years ago but I really like these paintings they're so good and they the nice change from the old reptilian model they're certain for this intermediate bird reptile model that we get now and you know this the skull on this thing is quite colorful because a lot of people are wondering was this thing living something like a puffin all these tip most of the pterosaurs come from marine coastal settings and some of them be found with fish bones in their gut if you look at isotopic studies of their bones they've been eating marine derived food and so the idea is that die more fur Don was also some sort of fish eater so I want to put pterosaurs in their time contacts so current best estimate for the age of the earth is 4.6 billion years we're only interested in about the last 540 million we'll zoom in on that I'm sure you'll recognize lots of these names and for our purposes again we're only interested in the Mesozoic the middle life from about 250 million to 66 million pterosaurs occupied almost all of that from about the middle of the Triassic right up to the very end it's 66 million and they were part of a huge event that happened during the Triassic you had this massive mass extinction at the end of the Permian at 250 where it's estimated some like 95 percent of species went extinct so you can imagine the decks were cleared on land and sea and it took a few million years for evolution to get back up and start producing new varieties of organisms and there's this huge variety of reptiles came out and that's what this is this is highlighting but there was another major extinction at the end of the Triassic which clobbered all sorts of weird and wonderful things from the Triassic you don't hear about them I think because a lot of the fossils are from South Africa or Eastern Europe or D girls and stuff but there's amazing stuff but pterosaurs appear as part of this major radiation in the Triassic and birds P R a bit later and then in the Jurassic but dinosaurs also appear at the same time as pterosaurs in this major Triassic radiation I'm so glad pterosaurs made it through they didn't they were they weren't very abundant in the Triassic and just one kind made it across the boundary it would be so sad if we didn't have this diversity that I'm going to show you later so the Triassic realize I'm saying it's a it's a key time but it was such a narrow window 50 million years out of 4.6 billion is just 1.1 percent and yet so much happened here's this slice again showing the huge variety and this is a stripped down thing because there's plant other plants and animals as well at this time so I just want to highlight who appears in the Triassic that we're familiar with today first Turtles the first frogs first crocodiles running around on two legs first mammals first dinosaurs and for our for us today we're interested in the first pterosaurs if you go back in time and to the Late Triassic the continents are still stuck together but they're starting to break up so you may have heard of Pangaea where during the Permian all the continents came together and formed this mass single landmass but in a late triassic jurassic boundary it's starting to pull apart I'm starting to see the continents fragmenting back again and just to orient you again here's north america and greenland there's western europe over there at south american africa and then what will become separate regions of India Australia Antarctica was also joined together so this was the the geographic setting and often think it must never have rained in the Late Triassic because there's no clouds so it's where do these earliest pterosaurs come from they come from fine grain sediments because their skeletons are so delicate they need exceptional conditions to preserve them so we've got one site in East Greenland and then there's a couple of sites in Switzerland in northern Italy and that's it and you can see they're near these ancient the shallow seas they're not on outer coasts which is sad for us because my great hope is why can't we find a pterosaur from the Triassic Marine rocks we get here in Western Canada it would be so nice to find them but I think the sediments that we got our marine fishes from they've further offshore and I don't think little delicate pterosaur carcasses were making it that far offshore so I may turn very blue holding my breath waiting for a terrorist or this is the earliest known pterosaur it's amazingly complete and it's amazingly sophisticated this isn't that some proto pterosaur a sort of flying animal this is a fully evolved very elaborate flyer with all sorts of specializations and that's a bit of a nuisance because it makes it hard to figure out who its nearest relatives are I just want to zoom in on the head to show how specialized it is so at the top is the drawing of the crushed flattened skull yet most pterosaurs are two-dimensional fossils with a few rare exceptions and if you look at the teeth it's got all sorts of different types of teeth along the jaw and if we when you look at even closer the smaller teeth vary they've even got try three cusps on them they're extremely sophisticated this is in total contrast to the earliest dinosaurs which have what's known as homodyne dentition the teeth are all basically the same but when if you look at the earliest pterosaur it's got what's known as heterodon dentition different teeth doing different things along the jaw so this is a cladogram showing the relationships of arca sores we know pterosaurs sit somewhere within orcas Oriya so they're not mammals they're not they're not amphibians there's not even crocodilians or crocodilian relatives but the hard part is it's because they're so specialized it's really difficult to determine exactly who they're related to and so not only are they super specialized but the fossils are very flat very thin and crushed the current favored idea oops is that they're closely related to dinosaurs that mainly is a lot based on the ankle structure this group named at the bottom or nithya means bird ankle so dinosaurs and birds probably share a common ancestor sometime in the middle triassic maybe as far back as they as the early triassic other groups are being proposed such as a group called the pro Lacerta forms that's the other second one but just a handful of people promote that most people like a close relationship with dinosaurs but there's certainly not dinosaurs they're very distinctive there's two main types of terrorists or once called the REM foreign codes and with others a pterodactyl oins and this this figure highlights some of the dista key details they've got basically the same body plan you just change the proportions of the various bones I think the biggest difference is in the the tail that the round four encodes have quite substantial but the the pterodactyl lights didn't need it and there's a little diagram of a restored RAM for incan with its tail and the pterodactyl would so people have thought that these guys because they were the first fliers maybe they weren't so good at flying and they needed this tale with a rudder of some sort so this the illustrations be done with this tail vein horizontal that would have controlled the pitch of the body other people think it's better restored as being vertical because that tail vein is actually most of them that are preserved are asymmetric which wouldn't be good if you're trying to keep us balanced and this frontal but it would work if you're trying to keep a as a rudder I think of these as like training wheels for for pterosaurs a few million years later the pterodactyl eggs have mastered flying better and they can dispose of the training wheels so there's this huge diversity that most people don't know here look at this a range of range of skulls they're so bizarre and when you really look at them they just get even more bizarre so that this diagram I stole from Dave on ones book from 2006 and he shows in dark blue the known fossil occurrences and then the pale blue although it looks a bit green on here is the inferred so yes the pterosaur fossil record is patchy but when you do cladistic methods like this it lets you connect up the dots and you can start to make predictions about where you will find pterosaurs in time and space and there's a really nice example that from that from from Alberta where Michael Ryan when this cladogram studies of ceratopsians he predicted he would find a certain type of ceratopsian he said will find it here in rocks of this age and he did so that's really nice that this has become like a predictive science and at the bottom there's these little icons of little feet this is the the these leaves and pterodactyls and these are pterosaur footprint record it starts in the Late Jurassic just at the same time as the pterodactyl Lloyd's appear we have no footprints for the RAM for encodes from the Triassic or from the Jurassic and it's thought that this reflects where these animals were living the interpretation is that the RAM for encodes were living in forest environments or rocky cliffs which would not be good for preserving footprints but the pterodactyl woods started to live in these shoreline habitats along oceans lakes rivers and they're also bigger so they have better way to making footprints or having their footprints recorded so I just want to highlight some pterosaur lifestyles the most common interpretation for something like ground for incus is that there are fish eaters their bodies are found so commonly in marine settings there's this late jurassic site in germany's old home and there's also another one Holtz Madden there's just loads of pterosaurs preserved in these fine-grained sediments sure and in modern in analog would be something like the turn catching fish we also there's the well-known Pteranodon there's about a thousand specimens of Pteranodon have come from Kansas that's chalk in inland sea deposits and these things were found hundreds of kilometers from the nearest shoreline and they're the analog is they thought they would live like albatross being out on the out on over water for four days and days fishing and I'm not enough of them perished far out at sea to become preserved so I want to say something more about round four incus and its diet because we've got a nice example just a few hundred meters away this is a specimen in our collections and you can see it's really nice you can see traces of the wing membrane around it there's also this tail vein on ours we can zoom in on that I hope you can make out the change in texture to see that tail vein on the end of it so it's probably been folded over on when it got flattened on the seabed so this is from this late Jurassic holt's zone - site 155 million years there's been hundreds of these things found but I want to zoom in on this part at the rear end of the body and words so we're now we're looking between the legs at the end of the tail and look at this structure here this looks like it's been ejected from the body and it's thought to be a coprolite fossilized feces and it's just packed solid with these little tiny hook lights look like things first we thought it was hooks from squid and octopus they're suckers have little keratinous or rigid elements to help grip but we showed pictures to people and checked in books ourselves and they all said no can't be from squid or octopus or ammonites or those other sorts of kefla pods they're not spines no one could recognize on that they don't look like teeth they don't look like scales but there's two clumps and it's the way the shape the size of position it looks like it's being excreted from the body so there's nothin sore their diet directly our specimen also seriously digested bits of bone we had a bunch of people look and everybody couldn't pick out anything in detail the thinking is that pterosaurs because they were active fliers had really fast metabolisms and very rapid digestion so things didn't keep their shape in the stomach very long because they were just quickly broken down no back to lifestyles the eyes dark heads were some of the last pterosaurs but they were also the extremely large and many features of their anatomy suggest that they were spending a lot of time on the ground as printer estriol predators and I found this really nice picture that's an unlucky duck it's so birds continue the tradition of terrestrial predation and this is Quetzalcoatlus what the largest known pterosaur although it's far from complete so the suggestion was what if these things were scavengers like like vultures today so these things are really big just like vultures are very big birds to muscle their way in on a carcass I also think one of the reasons Quetzalcoatlus might be big was to intimidate any of the theropod dinosaurs which were also there also Quetzalcoatl is unlike most pterosaurs was found at a site about 400 kilometres from the nearest shoreline well inland and a very arid habitat it's but it's remains to be found so this doesn't seem to be in your typical sea going fishing pterosaur another example there's pterodaustro this thing's known from eggs and babies and all the way up through adults and it's got this very bizarre teeth on this lower jaw they're you know few centimetres long there there's hundreds and hundreds of in the lower jaw little stubby teeth on the top and the interpretation is that these things were like flamingos they would have been filter feeding crustaceans from possibly saline lakes so and tera flamingos are pink because of the crustaceans that they eat so the idea is that pterodaustro might also be in pink because if it was eating these little crustaceans another example is thing called an erroneous the jaw meet the name frog jaw it's quite small it's got a bra a very large head broad mouth very big eyes and it's got bristles around a trim of its mouth and the analogy with this one what if it's a nocturnal thing eating insects on the wing just like a night jar they've got modified feathers which act as bristles around their mouths so they're I think already you can't you can appreciate that there's more to pterosaurs and good old Pteranodon oops so I want to say something about flying because that's what really really characterizes them so the two other winged vertebrates are bats and birds they've got the same basic structure the bones in their arms same as us like a humerus radius ulna wrist bones metacarpals manual phalanges but you change the proportions to make a wing so in bats you've got the fingers supporting most of the wing and the wing membrane goes between the fingers and down to the legs and down to the tail but in birds you've still got these same bony elements just shorten up the fingers and digits and compress them and merge them but the flight surface is formed by a different form of outgrowth of the skin it's the feathers and it's a it's composed of the separate elements unlike the continuous surface with a bat the bird one can can can separate so there they do the same thing they're both wings they function roughly similarly produce lift and thrust but the construction is very different and then there's the third version so it's thought that the pterosaurs are supporting a flight surface on this super elongated fourth finger and there's been a lot of controversy about how extensive is this flight membrane I just drew in these arcs arbitrarily but we do know that the flight membrane always comes down to the ankle in both groups in the round for encodes it actually goes between the legs but not in the the pterodactyls and then um there's also a small membrane on the front of the arm between between the elbow as well but the proportions on we have lots of preserved membranes for several different types of terrorists or and you can see that the proportions and the wing shape how much area there is it long and narrow or short and broad different pterosaurs are different flying styles for different types of habitats just like we see in birds today so I want to focus in on an amazing specimen of the wing we might think birds are quite sophisticated fliers but after what I show you here I think pterosaurs blow them away wait you see this so we've got this specimen called dark wings just think was just found about 10-15 years ago and the wing membrane itself is actually preserved thank the actual carbonized film and you can see the crinkles and wrinkles as the membrane was collapsing onto the seabed this is one of these a rare one that's almost 3d it's not squashed flat so what people did was they did some UV light imaging of parts of the wing and these structures start to be revealed you can see these tracts sir going around and then there's all this radiating structure starting from like the top right and coming down to the lower left and here's the interpretation of that it's thought these are blood vessels right out within the wing and the fine striations running across it are things called actin o fibrils all terrorists are being shown to have these super fine things finer than human hair and they seem to have controlled the stiffness of the wing and also how it would fold up but they've also got this there's also I'll show you shortly there's evidence for a muscle layer within the wing and sit and this blood circulation not only would it nourish the the muscle tissue but it would also act as a cooling surface I'll just show you them the next one this is from another site in Brazil with phosphatase so this animals soon after it went to the seabed bacteria are thought to have colonized the tissues and precipitated phosphate mineral right on the skin and muscle and you get I think there's a name like bacterial photolithography to record it and from that we can see these layers it's only if the wings that's only about a millimeter too thick so you've got a stiffening layer with the the bhakti no fibrils you've got a muscle layer which can actively control the tension within the wing and change its shape and then you've got this blood supply which nourishes the tissues but could also act as a cooling system because the wings wouldn't have had the furry cover insulating covering on them and if you've ever held up bird in your hand your hand gets very hot and sweaty very quick because birds are so hot so if you're an active flying pterosaur how better to dump that excess body heat than just circulate the blood out to your wings and you just radiate away the heat it's a really amazing system and I think this trumps a bird wing any day because birds with their stiff basically dead carrot and feathers they can't control the shape of their wing intrinsically not unlike these guys so if okay pterosaurs are in the air using their wings but how do they get into the air most birds if they're small enough can jump or they can run I don't know if you ever seen pictures of terrorists or albatross taking off from these South Sea Islands and they're on a slope and they're running and they're running and they're running you know these things got three meter wing spans it's unlikely that a really big pterosaur could run and run and run there with the membranes coming down to their legs they would not be able to get enough speed so either they're jumping off the ground if they're small enough maybe they're climbing up trees and jumping off but there's another novel idea which has come out so most pterosaurs bigger than today's Birds too big to jump what if they're using their arms this is an idea that Mike Habib has been promoting he came out of the Y sample lab same places Francois did and he's been promoting this idea that pterosaurs were using their arms like it they like the ultimate pushup and these were he's done all these calculations and done muscle restorations and he's worked out a sequence you can see it at the bottom there for how to lunch with your arms I think this is a really fun idea but I'm still not totally convinced could you produce enough force quickly enough to get yourself high enough that you could still get your wings to flap because if you look in this next sequence sure you can push yourself off the ground a bit but before you come back down you need to be able to flap your wings at least once to get enough power to keep yourself going up it would have to be very carefully choreographed so until I see a physical working model I'm still sitting on the fence but it certainly is an interesting idea so another amazing pterosaur thing is we now have eggs there was almost nothing for 200 years and then within the span of about five years we got three eggs from around the world mainly from China so this is this Darwin op Turris which is a double benefit because there's the egg but it turns out this animal is actually a perfect intermediate between the round for encodes and the pterodactyl eats you couldn't ask for a better intermediate fossil but back to the egg so one thing you can say is that this is with an egg being expelled from the body this is the first time you can actually say this is a skeleton of a female pterosaur you could never sex them otherwise and we can look at this egg bit more closely and you can see it's crunched down or squished down there's no broken egg shell there's little fine wrinkles as a soft leathery egg a bit like a lizard egg has been collapsed down so it's unlike a bird egg or a turtle egg which are quite hard and brittle and also from these Chinese sites there's actually embryos inside these eggs and this is a huge surprise because look how well formed these bones are look at the the ends of the bones are all nicely finished and also find it got bone tissue in them the interpretation is that pterosaurs weren't helpless little chicks in a nest these things were ready to fly almost as soon as they hatched and it's a very different reproductive strategy from birds old restorations showed pterosaurs coming to feed young in the nest we don't think that's the case now it's these things are independent just like you think baby alligators and crocodiles they come out fully equipped with teeth and hunting instinct and these things were probably the same so it's it's not good to use the burden Allen analogy for pterosaurs in a lot of ways but I want to highlight two famous fossil sites this is his own Hoff and quarry there's several of them in the in the neighborhood and so the since Roman times they'd be mining these flat lying limestone layers four floor tiles and there's also a technique came along called lithography you draw an image on these rocks but the quarry men working there keep coming across interesting fossils so it's not just pterosaurs misc little shrimps lots of fishes other types of crustaceans and crabs Turtles there's lizards there's earliest bird Archaeopteryx and there's even some dinosaurs but the pterosaurs are the really amazing thing there's lots of bits and pieces of terrorists are like isolated arms and legs and heads but it's the that's a more complete body fossils which are a really amazing thing and like I showed on our specimen we've got the wing membranes preserved you can see the wing membranes on this other round for incus here and there's also Pterodactylus with wing membranes around the arms so here's some illustrations of what these things would have looked like this one in the lower right this is this a new Renee this this frog jaw it's interpreted to be these aerial insect catchers but all the others are thought to have been fish eating there's another site again I showed you a previous slide for the well-preserved tissues from Brazil it's another one of these fossil luggage data with amazing preservation of a variety of things of sorts insects there's fish there's more fish and there's even a dinosaur so not only from Santana do you get 3d fossils you also get amazingly complete things and with soft tissue preservation look at the head crest on that thing on the lower right and it's from the 3d that thing's like an Han Guerra that people have been able to work out the Tao the joints work and come up with better ideas for Terrace or posture and how they could walk and I've got restorations for these but remember this one look at this the teeth on this guy in this crest and when you see it as the bare bones you still want to think it's sort of reptilian but look how it's been restored almost like a sea bird I think this is great it's so different and it's all unlike a bird it's got claws on its hands and it's actually touching up to its face there but but look at these weird crests there's several types of these tapi shards this the thing is on the right there with these absolutely unbelievable crests and if it wasn't for that saw exceptional preservation we've never have known about the extent of these crests it makes something like an hog wearer look conservative so this is what's come out in the last 20 years so time for my controversial but amusing and entertaining idea about these guys so I mentioned that Quetzalcoatl as' is found far inland long way from any shoreline and it's absolutely immense and I've been thinking what if and it's hard to get something that big to make it fly if you read about people trying to figure out the anatomy and flight potential list think they're bending over backwards and tweaking their numbers on unrealistically to may try and make it fly the pterosaur people really want it to fly but I think what if it's not a flying pterosaur what if it's a secondarily flightless thing and for good and bad we have nothing like a complete skeleton for this thing so when people are making these restorations 95 percent of this is conjectured based on what we know from other terrorist sores so I want to give you a few lines of argument that make me think this could be a flightless pterosaur so but five years ago I did this project looking body mass estimates for pterosaurs and so I made all these digital models of the two main groups I was really careful in making these models I wanted them to be as accurate as possible so i digitized all the the best restorations I could find i started assigning den different densities to different body regions so if you think density of water is a thousand grams per liter but terrorists arts have all these air sacs in their bodies like in the trunk region here and in the neck so I said let's reduce the density because of air sacs to down to 850 from studies of birds their heads and necks are extremely light down to like 300 grams per liter I also included lung volumes in these things based on relationships with birds because there I know I said you shouldn't use birds too much but birds and pterosaurs are both arca sores so they inherited a lot of their Anatomy from a common ancestor there's we know that there was even air sacks out in the arms and inside the bone and outside of it so the arms were less dense the legs are probably quite solid muscle in bones so there is still at a thousand and I even worked out what's the weight of the the flight membranes assuming that they're one or two millimeters thick and estimating the areas and so there's cats in my Quetzalcoatlus model down there at the body's about 6 meters long and so I calculated body masses and centers of mass and wing loading for all these things I came up with these graphs and so the top one shows body mass versus body length from the tip of the tail to the tip of the snout and the other one is wingspan these are common ways that bird masses are presented and so everybody was happy with all these body mass estimates all the terrorists are experts said yep these are really good nice and then I showed them like like Quetzalcoatlus mask way over here and they said nope can't be absolutely impossible I said why it just can't and they so you must have used a bad restoration well I've used the ones that are out there well show me one show me a new one well I'll get it back to you later so no one's come up with a alternate body restoration but they refuse to accept this big estimate but I think that's there they're lying to themselves that they buy into my other stuff they really like it but they choke on that one so here's some other things to think about Quetzalcoatlus this absolutely immense it's at least as tall as a giraffe a bull giraffe will weigh at least a metric ton and here's Quetzalcoatlus really stripped down lots of air spaces in it I get it at just over half a metric ton but some that terrorists are people are saying no it can't be more than 250 maybe 125 and some people have even said it's got to be 70 come on that's if it was going to be weigh 70 kilos 90% of the body would be air it just doesn't seem like a good thing here's another thing to think about the largest flying bird we have today is a 16 kilogram kori bustard and it's been reported that when these things go to take off they really have to work at it these things are at the top edge for a flying bird today the next size of bird up are flightless things like the ratites we will ignore the island dwarfs like the Kiwi and the kakapo from New Zealand let's stay with things that live on large continents so we've got like here's the the Rhea the EMU cassowary they start at 330 kilos and go up to just over a hundred so there's this gap between flying and non flying above 20 kilos there's nothing in between and let's look at the pterosaurs we've got pterosaurs something like topics whare going up to 23 kilos and just for a laugh really a laugh let's go with this 70 kilo supposed weight for this giant pterosaur if Quetzalcoatl is flying and topics whare and smaller things are flying where are all the other intermediate sized flying pterosaurs I would predict we should expect to see them but we don't the fossil record is completely absent for pterosaurs anything bigger than about Pteranodon so these these here's Pteranodon estimate 18 point six kilos for it and my critics said yep that's good we like that and they're all happy that it's like the albatross but look how light the albatross is it's less than half the weight of Pteranodon so Pteranodon had a wingspan maybe up to six meters as well but it needs pterosaurs everything about pterosaur is the extreme for lightness so the other thing to think about is pterosaurs were around for like 150 million years at least birds have been around and still around for the same amount of time so they've had all ëthat equal amounts of time to evolve different body shapes and ways of living birds have evolved flightless forms many different times independently different groups of birds have abandoned flight and the thing to notice is all these flightless forms are much bigger than their flying relatives the dodo is a type of pigeon and there's really good evidence for a type of pigeon in the South in the Indian Ocean area that's the close relative of the dodo and was able to fly between islands and so there's this huge variety of extinct birds that didn't or flower living birds an extinct birds that don't fly so if birds can do it why not pterosaurs so that's why I would like to think of Quetzalcoatl s as some sort of terrestrial predator scavenger and boy when I presented this to the audience at the meeting half the people thought it was really interesting and reasonable idea the other half hated it and the terrorists are people were really ticked off all the feeding frenzy was great but I touched a nerve it was it was it was fun parrying all the requests and my talk was the last talk on the last day and the broom was packed and afterwards people were constantly coming and challenging me or agreeing with me it was it was great fun so I'll leave it at that and oh yeah don't think Marc Whitten thinks the same as me he doesn't Marc's one of the new pterosaur gurus and he's all for Quetzalcoatlus still being a flyer so I'm done and I'll take some questions [Applause]

Channel: Royal Tyrrell Museum of Palaeontology

Views: 22,848

Rating: 4.8333335 out of 5

Keywords: Speaker Series, Royal Tyrrell Museum, Palaeontology, Paleontology, Pterosaur, Pterosaurs

Id: BtSvSX7Cn60

Length: 44min 38sec (2678 seconds)

Published: Thu Jan 11 2018