The World's Best Preserved Armoured Dinosaur

good morning everyone and welcome to the 2018 royal tyrrell museum speaker series today the Royal Tyrrell Museum and it's cooperating Society are proud to present our very own dr. Caleb Brown caleb is the Betsy Nichols postdoctoral fellow here at the Royal Tyrrell Museum caleb is originally from northern British Columbia but grew up in Red Deer Alberta he received his bachelor's degree in zoology from the department of biological sciences at the University of Calgary and spent three summers during his undergraduate years working in the preparation lab here at the Royal Tyrrell Museum after completing his bachelor's degree Caleb stayed at the USC to pursue his master's degree again in the Department of Biological Sciences where he investigated the diversity of small plant eating dinosaurs in the Late Cretaceous of Canada after successfully defending his thesis Caleb moved out east to pursue a PhD in the Department of ecology and evolutionary biology at the University of Toronto for his dissertation he studied the variation and evolutionary morphology and horned dinosaurs from dinosaur Provincial Park fresh out of his ph.d Caleb moved to Drumheller to take on a postdoctoral fellow position here at the Museum Caleb's research interests focused primarily on the evolution of dinosaurs particularly of ceratopsians over the years Caleb has conducted fieldwork in Alberta Saskatchewan the Northwest Territories China and Mongolia today Caleb will give a talk about the world's best preserved ankylosaur boreal Pelt ax and what the new information about this specimen has revealed about armored dinosaurs so without further delay I present you dr. Caleb Brown [Applause] hey can you all hear me at the back okay thanks fence Paul thanks for all coming this morning first off I have to apologize because I am dealing with a bit of a cold so hopefully my voice will hold out for the whole talk in spite of that I'm actually very excited to be here because I get to talk about this specimen which is by far the coolest specimen I've ever been involved with researching and probably the coolest I will ever be able to be involved with research and it is the exceptionally preserved notice or that our museum announced to the public in the summer just last summer and what I hope to do with this talk is give you a bit of an introduction into the specimen some of you already know the story but I put the discovery the collection preparation and then talk a bit about why it's unique and highlight some of the research that's been done so far and that's just the tip of the iceberg because it'd be a lot more research done on this specimen as it progresses the first thing that's I need to mention about this animal is that its discovery was actually quite miraculous and that's because it was discovered by this machine here this excavator in the the oil sands mines Suncor millennium mine north of Fort McMurray and you don't want to get a good sense of scale in this image here's a sense of scale with a person these are gigantic excavators the operator will be standing almost ten meters above the ground and each bucket full of rock that it picks up can contain up to 44 cubic meters of rock so the fact that this is what hit the dinosaur and the operator noticed it we need to be very give proper attributes to the discoverer and that was Shawn funk he was the operator of this equipment that day and on the afternoon of March 21st back in 2011 he was doing overburden removal so he was digging through the rock down to the productive layer the layer that has the petroleum in it and he noticed that he hit some rock that was unusually hard it was much harder than all their surrounding rock and him and his supervisor marathon stopped and they they saw these kind of polka dot-shaped rocks coming out of the hill and this is what they found kind of posing happily next to their find and instantly they knew this was something important it needed to be reported now the fossil laws in Alberta are some of the most progressive in the world in that any industrial mining in areas that have paleontological resources it needs to be monitoring and if anything important is found it needs to be reported to the proper authorities which in this case is the royal trail Museum and then we respond we assess the find and try to collect as quickly as possible and that was the case here with some course help we had a team on the ground in a couple of days and that team was led by Donald Henderson our curator of dinosaurs and Darren tankey one of our senior technicians and their job was to assess the find figure out what it was and the best way to collect it now before I can go any further need to give you a bit of context because the rock that they're digging through in this mind is actually marine rock back in the Cretaceous there was a large Inland Sea covering most or the central part of North America and the rock that they're digging through is called the Clearwater formation it was deposited not in rivers or flooding events that we see the rock around from Hillier but it was deposited out in the marine shores it's actually also much older it's about 40 million years older than the rocks in the Drumheller area or the rock down and down super flinchin Park because it's a marine environment we would expect to find marine animals and that's the case most other stuff that's been found up there and we have got a lot of weather exquisite animals have been marine animals so here on the top we have Nichols or which is a plesiosaur and on the bottom we have Athabasca source which is an ichthyosaur so this was kind of the default assumption going in that what we had was probably another marine reptile that changed fairly quickly on the ground with the notice that we had actually preserved osteoderms this is armor that's preserved in institution in place for the animal and because there's armor it actually really limits the amount of possibility so who could or what could be preserved in terms of the skeleton what an osteo term is is it's basically a bone embedded in the skin it basically means skin bones and there's a lot of animals alive today that have osteoderms things like armadillos crocodiles various lizards and there's also a variety of things that that were extinct that had off to terms as well just to show you what this looks like in a more internal sense so here are some amazing CT scans provided by Ed Stirling at the Florida Museum and on the left you have the animal as it was in life and the right you have a CT scan everything but the bones has been removed and it's kind of color-coded it so all the stuff that's tan that's the internal skeleton that's the skeleton that we we have and all the green stuff is the osteo turk those are separate bones embedded in the skin and the big take-home message here is that those bones are connected to the rest of the skeleton they're kind of loose they're held in that skin they don't actually connect to the internal skeleton the best example of osteoderms or one of the best examples we have today are living crocodilians and the picture on the top you can see what the skin looks like while the animal is alive it's covered in this kind of leathery skin but within that skin you have these bits of bone that form this network that cover the animals back and the sides and the belly so given that we have these Austin herbs and that they are fairly widely distributed in these distinct rows we knew that this was from what's called a firing of foreign a armored dinosaur this is the group that thinks food like sorry include things like stegosaurs and kylo sores and they're characterized by their armor they have kind of two different skeletons they have an internal skeleton of endoskeleton shown in blue and this is the same skeleton that we have the bones are the same they're just in different numbers or different proportions and sizes but uniquely they also have what's called an exoskeleton or dermal skeleton and that's formed by these osteoderms bones embedded in the skin and this is much rarer in terms of animals that possess osteoderms and if we look at the pattern of evolution of the dermal armor in the armored dinosaurs we see a very general pattern where the earliest forms have kind of simple small armor spread throughout the body one group then has the armor restricted to pair of rolls that run down the back and modify tentative plates or spines and a good example of this is Stegosaurus and this is the group called Stegosaurus and there's another major Asian called ankylosaur eaten and this includes both ankylosaur they and notice or date and they have often was widely distributed along their body but they tend to have them in very distinct transverse rows especially around the neck and i calliphoridae specifically has a tail club that's made up of Austin's at the tip of the tail whereas notice or day does not have a tail club and instead they have large shields or a large I'm sorry spines coming off the shoulder region this is one of the areas that gets confusing because the term and Kaila sore can mean two different things there's multiple different things that can mean a callous or eyassa entire group work can often mean just in callous or day specifically so when I'm saying I callous or I mean a callous or you could think was both in callous or a day and notice or a day and fairly quickly it became obvious that what we had here was an important specimen and an exceptional specimen for a number of reasons first off all those osteoderms they're still in place they're still in the original pattern and the endoskeleton here we case have some vertebrae preserved and some tendons they're also in the original position this is what we call articulated and this is important because it means that the bones are still in the life position they're not all jumbled up we can learn a lot more about the anatomy when everything is still in place but we didn't just have the bones preserved there was other stuff preserved as well we have you can see these diamond the rocked agonal shaped black areas or dark gray areas this looks like it might be preserved skin associated with those osteoderms and there's also these kind of amorphous blobs of gray with this orange spheres and this might be stomach contents so already we have an articulated dinosaur possible skin possible gut contents so it was something that was definitely a high priority important specimen but we didn't really know how complete it was those blocks that I showed you initially those come from the hip region era called the sacrum and that's what had fallen out of the cliff and had been noticed by Sean but half of the skeleton was still up high in the cliff we didn't either you can see a cross-section here showing kind of the bones still coming out of that cliff but it wasn't clear which half was still in the cliff did we have the top situation where the front end was going in and the skull was so probably there or the bottom situation where the tail was in the cliff and the head had already been hit and hopefully of course we have the top situation and as many of you already know that is the case we do have the front half of the animal preserved which is much better than having the back end preserved so in terms of a collection the first stage was kind of a salvage because it had been hit by the excavator there was chunks all over the place so a couple of days were spent collecting everything off the ground and hopes of putting this back together back at the museum of putting the animal back together the second stage of the excavation was getting down to the part that was still in the rock and that was done largely with the help of Suncor and the big equipment that they had on site they both dug down to the level of the the fossil being or the fossil in the cliff and also using that rock to create a wrap for easy access from below the idea was to isolate the skeleton to one large block dig underneath that coated in burlap and plaster and cement and then try to lift it out onto and awaiting a truck unfortunately as many of you know there was a bit of a catastrophic failure the jacket didn't hold and it broke into two big chunks at a whole bunch of little chunks so again it was back to kind of a salvage situation pick up all the pieces bring them back to the museum and put them back together again but despite this a couple weeks later all of the chunks arrive here at the Museum and they're offloaded back into our collections facility ready for preparation and this isn't the end of the kind of first part is actually at the beginning because the next step is the preparation and the specimen was handed off to the very capable hands of mark Mitchell who's one of our long-term technicians and Mark's job was to slowly remove all of the rock down to the surface of the specimen consolidate everything glue it back together and put everything back in the original position there was no easy task here are some just photos showing the progression for that skull excavating it from the rock exposing more and more and getting it ready for research and display now mark started the preparation in April of 2011 and he didn't work on much else other than this and he didn't complete it until December of 2016 so took about five and a half years of dedicated work about 7,000 hours basically just working on this specimen alone and the reason it took so long is a couple of factors first off the size the bigger the specimen the more time e to put in to prepare it and get it ready for research secondly the rock was very hard and although the specimen was incredibly well preserved it was very soft mark describes it as kind of compressed talcum powder so he was fighting millimeter by millimeter to expose it without damaging the underlying fossil and finally normally during preparation you're removing rock down to a bone surface and bone has a very discrete outer surface in this case on top of the bone there was often skin or some other saw tissue which is much less obvious much more discreet to be much more careful not to remove that thin organic lining but after um five and a half years what emerged was one of the best-preserved dinosaurs ever found I'm sure many of you have seen it if you haven't you have to go see it in the galleries it is without a doubt a world-class specimen and there's one reason that makes it so distinct it makes it unique from all the other dinosaurs that have been found and that's the combination that almost the entire surface is covered in preserved skin which means you can't actually see the skeleton underneath and preserve dinosaur skin is not rare we do find lots of patches which sometimes we have fairly large patches but when we have skin preserved often the animal is kind of flattened like a pancake it looks like roadkill or looks like a dried-up piece of beef jerky in this case that's that's not the situation the animal retains its three-dimensional shape so it looks now as its preserved almost exactly the same as it looked back in the Cretaceous which is quite a thing to think of it it's hard to over us over and describe how well-preserved this is these in great photos from Robert Clark from National Geographic and I just want to highlight some of the really cool features really distinct features about this animal first off it has this very triangular skull this is a notice or characteristic and callused had a very short rounded skull so instantly we know that this is a Novus or it has these three large rows of osteoderms on its neck with big keels and those off sodium's also continue all the way down the back and then in the shoulder region it has this large spine called a para scapular spine kind of sticking out from the side there's a few other more subtle things in the animal if you haven't seen these go check out in the gallery after on the animals right side behind that spine there's this lump of skin that looks like an old catcher's mitt that's because it kind of is it's the preserved forefoot the preserved paw and what you're seeing is the underside the skin on the palm of the hand basically that's preserved there and there's also this large mass of what a soccer ball size mass between the hips that we think is stomach contents we're currently analyzing trying to figure out what this animal may have eaten so all of these things kind of set it apart as it is a unique specimen what I want to do is sorry even though it's very well preserved it's not complete it was hit by the excavator initial parts of it had knocked off or been removed before it was noticed so even though it's incredibly well-preserved we only have about the first two thirds of the animal I'm gonna zoom in on some of the osteoderms in the neck region and show you a bit more of the anatomy up top you have just the photograph on the bottom you have a bit of interpretation there and the big thing here is that there's alternating rows of polygamous scales in this green color and then all steo terms in the orange color whoever Austen terms are the bony components of the armor but if you look closely on top of the offs to terms you see these dark grey patter patches that cover a lot of the austere rooms what those represent is the EPI offs to dermal scale or the cratis scale that would have once sat atop of the osteoderms just to give you a better context of this let's go back to our stand comparison so here's our here's our crocodile and if we look on the images on the left that's what it looks like in life it has this kind of leathery look to it and the officer that was inside the skin when all that skin is removed and we just have the naked osteoderms it looks like the condition on the right we have these kind of round really porous almost honeycomb like instructions and that naked austin room is how we usually find them for ankylosaurs whether they be isolated or associated with this guilt and that's what we're used to seeing but in this case we don't just have that we have the covering on top and this is nicely shown by this great histological section by burdens and colleagues from 2011 so what they did is they took crocodile skin or alligator skin and cut a very thin section looked at it under the microscope to identify different tissues just very basically we can talk about those three main tissues we have the Ostia Durham itself which is this triangular structure in the middle hat and orange that is held in a matrix of the dermis the deep part of the skin shown in green and then on top of that off students have this craftmas scale which is epidermis and that's that leathery or maybe even like fingernail type material that you have that's really tough on top of the osteoderms so if we go back to our notice or that's what we see preserved on those Austin's that's amazing but we don't just have that on the neck we have that throat the whole animal hears offs two terms along the back and you can see again rows of austere domes and scales and then there's that craftmas covering that's preserved on those osteo terms and this is best seen on actually that shoulder spy here's a close-up view and you can see the only part that is bone is that little orange bit there the rest of the structure is all Brattain as' it's all that a foreign language or the fingernail like material that's preserved so because we have these different tissues preserve one of the first steps we have there's actually mapped this out and show what's actually preserved in this animal we can do that and in this case the light yellow is the off student abode of the off stream itself in the dark gray on top is that crappiness scale we don't usually have that was almost no other cases where that's preserved you might notice in the sacral region there's none of that preserved that's because that's actually not prepared out in three dimensions that was a pardon counterpart so I broke in the plane of the skin almost like the pages of a book so one of the things that we can do to help identify these different types of tissues is look at it under different spectra of light so this is what it looks like under visible light so this is light that you see with with human eyes and you can see different tissues that are fairly obvious you can see this orange is the osteo term the black is the skin we have some of the internal skeleton there but what happens if we look at it under different wavelengths of light so first off we're gonna look at it under UV or ultraviolet light and it looks similar but there are some things that jump out first of all those these dark patches some of the officer rooms are darker and that's because they were covered with glue in the field and the glue actually acts to absorb that UV light I wanna stress that this isn't UV fluorescence this isn't stuff that's being sent back in visible light this is actually UV light that's reflected in and captured with a UV modified caption camera and you can see here's a picture of Darrin I think this Darrin applying glue to the Austin's in the field to consolidate them so using this we can tell where a glue has been applied and where we haven't had glue applied you might also notice that there's this white patch in the top left and that correspond to the stomach contents there so there's something there that's actually reflecting UV light more than everything else what's really useful though is if we look at this under infrared light here you can see the Austin Aries glow they're reflecting a lot of that UV light so they're really easy to identify and that's in contrast to the endochondral bone of the internal skeleton which is kind of this medium gray color it doesn't reflect you'd be like nearly as much as the austere domes and then the black is this really UV non or IR non reflecting skin so what we can do is we can combine these different wavelengths into what's called a false color composite and all of this stuff was done the help of courgette Kolski who helped with the multispectral photography and really this just helps you to show the different types of tissues that are preserved that we don't normally get to see her that art has distinct with our normal visible light spectrum that we're used to seeing and this is useful because we can use this then to figure out blocks that are less obvious so here's a block through the mid part of the animal this bit here is that that catcher's mitt of the front paw and you can do there's some interesting stuff happening in the middle here but we're not really sure what it is so if we look at it under ultraviolet that's not overly helpful but here's the infrared and you can see these light up again these are osteo terms we can put we can make that in false color composite and there's this very bright pink color there's the awesomes that our Institute in place and here's AA students that have actually co-opted that I've actually been displaced as the body cavity collapsed after it was buried contrast that with the internal skeleton part of the the hip they're preserved as the ilium so techniques like this were actually very helpful helping us map out the different tissues that are preserved when we have a specimen like this one of the first questions we need to ask is is this something new does this represent a new species and to answer that we need to compare it to all the other known or named species and see is it distinct from those or is it is it already covered by one of those species and really we're looking for distinct or unique features so we call these autop amorphous or things that make this animal different now what I'm gonna do is I'm gonna show you some of the features that make it unique or that that are shared by a small number of animals to do that I'm going to use this beautiful skeletal illustration done by Donna Sloan and just for reference there's a googly-eye in the orbit and a nostril there so the top view is of the top of the skull looking down and the one on the bottom is a side view looking at the the skull and the first row of armor on the neck one of the things that the armored dinosaurs have is they have a series of cranial dermal plates also help capitain Ely and these are basically plates of bone that are either fused to the skull or outgrowth of the skull and they cover most of the skull itself and this animal has this one large kind of sub octagonal plate that's in the frontal pride where you just work up in the forehead region but if you look in the nasal region it has a whole bunch of small round irregular shaped plates above the eye it has a super orbital creating a little plate that has this very sharp Ridge along the edge of it and then below the eye it has this very large Jugal or cheek plate that's actually bigger than the the eye socket of the orbit and it has a sharp point on it as well it's also a couple of features of the post cranial skeleton that jump out as being distinct first off after point up that has these alternating rows of osteoderms and scales all the way down the body and the rows of Austrians don't come into contact they're separated by those scales the shoulder spine that para scapular spine is massive it's the largest spine it's about half a meter long it projects from the side of the body and then it curves backwards the third sixth and possibly ninth row on the back of these Austin's they kind of pinch out laterally they don't make it to the side that's a unique thing we don't really see in a lot of other and connoisseurs and then finally looking at the neck the austere Durham's in the cervical region of the neck region they have very prominent keels and the apices of those keels project past the footprint of the off to term so all of these things in it and other things as well suggests that this was a distinct new animal so we gave it a new scientific name and that bore a lapel Tom mark Mitchell I just to kind of explain this a little bit the boreal up elta boreal means northern in Latin you here with boreal forest or aurora borealis Pelt ax is from Greek it means shield and that's a common ending for armored dinosaur names and then Rachele of course honors mark which lie of course honors mark mitchell the preparator who spent so much time working on it and we felt that that was a valuable contribution that should be rewarded with being named so we know what's something distinct but we don't really know who it's related to which other animals it's related to and that's the next question and to do that we look for shared features that unite a smaller group of animals these are called sineva more feasibly called shared derived characters but there's a bit of a problem with this and that's because as I mentioned before there's skin reserved all over the surface of the animal so we can't actually see the internal skeleton now most other ankylosaurs we only know from the internal skeleton so it's hard to make direct comparisons for like comparing apples to oranges so ideally you the greatest x-ray and see what's inside and see if we can demarcate the internal skeleton for comparison and often we can do that using CT scanning so we took it to Calgary and got a CT scanned unfortunately this was not successful for a couple of reasons the first reason was that the rock itself is radio opaque basically it reflects back those x-rays it doesn't allow them to penetrate and just the size of the specimen an amount of rock on it as well made it very hard to penetrate so this didn't pan out as we were hoping we are still working on trying to get it scanned with a more high-powered scanner the problem is that the specimen is so large and so heavy yet at the same time it's so delicate it's difficult to transport and it's also currently on display so it's a balance between conserving the specimen making it available for the public and research what we do is we look for a variety of characters or traits and in this case we're using the character matrix of Arbor at all 2016 so a series of anatomical features that we quantify for each animal and using this matrix there's 92 for the skull there's 66 for the post cranial skeleton and there's 25 for the armor so 183 in total when we look at our animal though unfortunately we can only code about half of those for the skull and half of those for the armor that's because we can't see inside the skull and it's also because we've lost the tail the really bad news is we can only code what 8% for the internal skeleton again because it's cloaked it's hidden by the skin so all in all we can only evaluate about one-third of these characters for this specimen even though it's one of the best-preserved in the world and that's because it's exceptionally preserved we have stuff this more important that's actually blocking the internal skeleton so in some ways it's actually too well preserved what we do once we've coded all these characters is we plug this into a computer program and makes all the possible trees all the possible relationships between the different animals and it evaluates how many evolutionary steps were needed to make that tree and basically chooses the simplest tree and unless we have other knowledge we like the simplest answer and as we add more data will of course get different trees and then become more complex and they'll continually change so this is the the result from that analysis this is a phylogeny basic the family tree of armored dinosaurs it's also time calibrated so the vertical axis here is time blue at the bottom is the Jurassic green kind of halfway up is the Cretaceous and the way you read the pattern of relationships that the closer the animals are in terms of the branch and less steps you have to go through the tree the more closely related they are and we have the two distinct group you have a callus or a day and notice or a day unsurprisingly our specimen comes out as being a notice or so from now on I'm going to be mainly talking about notice swords and not talking about a callus or any at all and it also occurs temporally about halfway through the range at which notice ORS occur and it occurs right in the middle of that group which is interesting so we can ask questions about what does this actually tell us about notice or evolution does it actually reveal interesting and there's one thing that I think is quite interesting in that the earliest forms things like gargoyle asaurus here from the Jurassic if you look at those cranial dermal plates they have a large number of irregular plates on the top of the skull the latest forms the forms you find in dinosaur Provincial Park and Late Cretaceous here things like canola source at Mont onea they have a much reduced number of plates and they're very complex and they have very specific shapes if we look at the things that boreal appel that comes up next to in terms of its its closest relatives those are poposaurus and europe alta both from about the same time but Allosaurus has a situation kind of like gargoyle as horace very large number of irregular plates whereas europe Alta looks very similar to those in the Late Cretaceous so what does what does boreal a call to look like well remind you it has this one large plate over the forehead area and then a whole bunch of small plates on these actually kind of transitional between these two forms it looks like the back end of the skull the capitate you laid either fused together or reduce the number first and that shifts anteriorly that's just one of the things that this can reveal about the notice or relationships but I think the coolest thing the most exciting stuff is actually what it can tell you that's unique that other specimens can't tell you and that's of course because of the preserved cratis cheese so this is that same family tree I've just rotated 90 degrees and here are the five best preserved and Kaila sores again light yellow or the off to terms light gray is skinned or scaled and then the black are the coverings of the off students and the take-home message here is that the notice were that we have here is really the only one that preserves those crappiness scales in any number that we can actually analyze so that's the cool thing that we can play around with it try to get some interesting answers for so if we go back to our kind of tissue map of where the different tissues are preserved one of the first things we have to do is actually kind of come up with a grid or anomic lateral scheme to identify the different osteoderms that kind of a numbering system and we do that by basically dividing into regions so that the neck or the cervical region is in red the back where the thoracic region is in green you have this transitional zone shown in orange and then the sacrum where the hip areas in purple and the four limbs are in blue and what we're going to be doing is what we did especially measure up all the different dimensions of these Oscars quantifying both the shape and the size and seeing how that varies along the body and seeing if there's interesting patterns and really what we're interested in is something called a llama tree which is how different measures scale relative to each other so as something is one feature grill with does the other feature grow up the same rate or does it go faster or slower and in particular we're looking at how the height of those off streams or have a low overall length of those awesome changes so this is a plot of the length of the base of the Austin versus the total length so how long is that including the apex when the heel is included and what you can see is is this very strong linear relationship here all the data fall on one line and pretty close to that line except for one it doesn't matter which part of the body of it they're from so a green red and yellow all fall along this line except for this star this is one outlier it doesn't fit the pattern this is that Paris capparis pie over that shoulders by this plot is when we treat left's and rights and we average the two together this is the same plot when we separate those and use them as two different data sets and it shows the they fall out right next to each other so the left and the right are preserving the same pattern in terms of that shoulder spine is doing something different what this means is that the osteoderms although there's a huge variety in terms of the shape and the size from the neck to the back most of that shape change can be explained by a simple mathematical equation showing how one shape changes we all have to fill a shape but that one mathematical equation does not explain them the pair of scapular spine something different is happening with this by it's much taller than it should be compared to everything else so why is that well we can look at the specimen itself and one of the things that we can see is a it has this really large creatinine structure we saw that originally here's the austere derma core and this is all preserved cretinous sheath this looks very different to the alligator that I showed you before with the histological section and it actually looks superficially very much like what we'd see in actually a horn of something like a cow that's live today where you have again a bony core and this sheath so horns just like osteoderms they have a bony core and then that's covered in this kotnis tissue in this case is called a sheath and not not a scale and it's often that cratan is covering that adds either interesting shapes or exaggerated s' the underlying size or shape of the horn core so we can compare that large osteo term in boreal Pelt ax to the horns of modern mammoths and what we're seeing is basically the height of the yellow bars that is the core the bony part and the height of the gray part is the crap this part you can see it compares very favorably to animals like boss and bison the domestic cattle and bison that we have here today and it also compares in a relative sense very favorably to horns of lizards today especially chameleons and much smaller but the relative size of the horn and the sheath is much better analog than it is to something like and a crocodile ah stator but we don't just have that one large spine preserved we have the spines preserved from all over the body we have all those correctness coverings so we can actually fit how that scales across the animal so here's a similar allometric plot but in this case it's two different tissues so on the x axis here we have the length of the bony core so the yellow part and on the y-axis we have the likes of the sheath we're looking at how those change size or how they change proportion as the students get larger and the big thing to highlight is that isometry this dotted line here that's the line where there's no shape change where they grow at the same rate the slope here is about 2.2 to 2.6 depending on the type of regression use that means that as the as the bony part grows at one rate the cretinous shield sheath grows at a rate that's about 2.2 times or 2.5 times faster so it's more than doubling the size as the off streams get larger we can just visually see that here's some of those off sperms and for the small ones on the back you can see what 3% or 6% of the total length is from that sheath and that's similar to what we see in Austin's of animals today like an alligator but when we have the large spine about 25% about a quarter of the entire length is that sheath and that's similar to more similar to what we see in a floor but we can actually quantify this over a larger scale so people have measured horns from a variety of living animals and published the data so we can actually use that data and compare it directly to the notice or this is that same plot I showed you before here's the here's the notice or off to terms here's that line of isometry this is the bone part this is the gratest part and what I'm gonna do is I'm gonna throw up data for a variety of living animals with horns first off here's the regression for the or the line of best fit basically regression for the notice or here's the data for Franta soma this is the horned lizard we have these in southern Alberta this is chameleons the horned chameleons here are mountain goats again Alberta species pronghorns and then we have our domestic cattle and our bison bighorn sheep and finally cap or some of these goats with these massive horns I don't want you to take away all the details I want you to take two eight two main results from this the first is that these lines are not parallel as the off sternums get larger these lines converge on each other so as the Austrians get larger they become more horn-like and the second thing is that the Paris scapular spine shown with this green star here falls right in the middle of the data for living domestic cattle in terms of the relative size of its horn and its sheath so what this means is that when we compare extinct animals and try to figure out their behavior we really want to compare them to modern animals they're called analogs and for the most of the awesomes we've been comparing historically to things like crocodiles and that makes a very good analogue and we think these might be for some sort of defense I would argue that when we see really large exaggerated off streams like the Paris cap or spine here perhaps a better analogue is something like the cranial horns of mammals or lizards today yeah why does that matter well if you look at the function of horns today often you think of them as being defensive structures and when push comes to shove animals with horns will use them to defend themselves you can see that here but the evolutionary driver that that resulted in the evolution and the exaggeration of those horns is in almost all cases some form of sexual display whether it be a combat with members of the same sex so males competing over territory or females or males trying to impress the females the second thing I want to talk about in terms of the research is the preservation of color and if I was giving this talk ten years ago I would have said we don't know anything about dinosaur color you can use your imagination artists can do whatever they want that's changed in the last ten years mainly based on work from Jakob Pinter who's one of our co-authors on this particular project looking at preserved color in just a very quick explanation is that color can be preserved in fossils in two forms it can be preserved chemically so the actual original chemical structure is preserved or it can be preserved structurally for the melanin group of pigments there's two types there's eumelanin which is the black pigments if you have black hair that's mainly what's in your hair and there's FeO melanin which is the red color so you have red hair it's mainly Feenie melanin and they have a different chemical structure and they also have a different shape to the mulana soul so a lot of somes are basically little bundles containing pigment and the shapes of those bundles depending depends on how much famil and versus how much email and then they have in the bundle and you can see here here's an example comparing fresh Milano somes to false Amano so I'm so we can infer color based on both of these things so we invited ya cup to come and take some samples and see if you could find any Milano somes preserved you have skin preserved so maybe there's color preserved the bottom SEM here a scanning electron microscope image shows what the texture looks like and there's no Malena somes basically the either the heat or the pressure resulted in the mouth so basically dissolving so we don't know what's there so that was a was a negative result but we might still have some preserved in terms of the geochemistry so that was the next question and we again took samples and we subjected those samples to mass spectrometry basically small bits of the sample is destroyed and then you look at the the particles that come off that the charge and the mass of those you can figure out what the original organic compounds were so in this case there's this is just four samples we've done lots of samples but the first top or the first the top three are all samples from the skin and the bottom sample is a control sample so it's from this sediment and each of those Peaks represents a different organic molecule and the ones highlighted in black are breakdown products of you mail it in the black picker but they're not exclusive to you mail it and the ones in brown are eumelanin and pheomelanin they're really important highlight is the one on number 14 in red that's a organic molecule benzo thiazole and that's diagnostic to fail on so one failed on and break down to the heater pressure it produces Benza Feisal so based on this we were able to suggest that the animal had contributions of both fail melanin and eumelanin to its coloration it likely had a rusty red color in life not only did we have the idea of what the coloration was we could also look at the distribution of that color and based on the cross sections of the animal in several areas you can see that those dark organic layers are much thicker on the back of the animal and they petered out towards a size besides and this is most easily interpreted as reflecting the original pigmentation of the animal so being dark on top and lighter underneath this is a pattern called counter shading so why is this important well this is the audience-participation part of the talk so there's two choices two balls one of them may appear to be coming up towards you and one of them may not so who thinks a appears to be coming towards you and who thinks B appears to be coming towards you okay you guys all passed did you know why you did that light source so you made whether you knew it or not you made two assumptions the first assumption you made was that the light was coming from above and that means the top of the sphere is lit and the underside is in its own shadow and the second assumption you made was that the object is of consistent color okay and our eyes are attuned to pick this up as a three-dimensional shape even though I can assure you that screen is is two-dimensional it's not just us other animals that are visual predators will rely on picking up these visual signals to see three-dimensional objects so if you're an animal and you want to hide I want to camouflage yourself you have no control over where the Sun is that's beyond your evolutionary control but you can control in an evolutionary sense your coloration or your pattern of coloration and what many animals do is they have a pigment that count that's opposite the pattern of light so dark on top light underneath when you add that to the pattern of the light source they capped each other out and it helps to at least diminish your three-dimensional love line this is called a counter shading our self shadow concealment it's very common across pretty much all animals today and there's some exceptions one of the biggest exceptions is that when animals get large they tend not to be counter shaded anymore things like elephants and rhinos are counter shaded and things that are get large as adults they also tend not to be calculated as adults there's a great example with bison here you can see the juvenile is counter shaded the adults actually opposite counter shaded and this is because as adults these animals do not face large predation pressures so it doesn't they don't need to hide on the landscape or is this very important for smaller animals or for juveniles so we can quantify this pattern looking at the number of species that are counter shaded in different size classes so getting larger towards the right and you can see the percentage of counter shaded taxa drops off to nothing and that that hashed area represents body sizes where animals are no longer subject to predation pressure as adults so what what does this matter for Borella felton well if we toss Borella pulta in there it falls in that area where animals today are not counter shaded and are not subject to predation so what this means is that even though Borella peltor was a large one and a half ton heavily armored dinosaur it still relied on visual camouflage to hide it was still subject to predation pressure from the large carnivores of that day and it just provides evidence how much nastier that predators were back in the Cretaceous than they are now and how much large they were so based on the preserved anatomy the osteoderms all the details of the scales details of the pigment and the counter shading we were able to work with several different panel artists to reconstruct what this animal looked like and what you're seeing is three different and what this animal may have looked like back in the Cretaceous and the bottom one really highlights this idea that even though this was a one and a half ton dinosaur tank it was still subject to predation and one of the big predators at that time would have been something called Acrocanthosaurus this large looks like trying to source but it's not actually very close ready to try to source at all I do have a whole bunch of people to thank and I'm sure there's people at the museum that I forgotten off this list here

Channel: Royal Tyrrell Museum of Palaeontology

Views: 32,403

Rating: 4.9173837 out of 5

Keywords: Speaker Series, Royal Tyrrell Museum, Palaeontology, Paleontology, Nodosaur, Borealopelta, Borealopelta markmitchelli, Armoured dinosaur, dinosaur

Id: YCXMw7xyKao

Length: 51min 13sec (3073 seconds)

Published: Fri Mar 16 2018

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Dr. Caleb Brown, Royal Tyrrell Museum of Palaeontology, talks about the world's best preserved armoured dinosaur.

In the spring of 2017, a new armoured dinosaur was publically unveiled with the opening of the exhibit Grounds for Discovery. Borealopelta markmitchelli was discovered in the oil sands mines in northern Alberta in 2011 and took nearly 6 years to prepare. Borealopelta is the best-preserved ankylosaur (tank-like, herbivorous dinosaurs) in the world and one of the most spectacular fossilized dinosaurs ever found.

Preserved skin and armour cover the entire skeleton, maintaining the original three-dimensional shaped of the animal. Even the animal’s last meal may be fossilized in the stomach. This high level of preservation gives scientists an unprecedented view of what this animal looked like and to how it lived during the Early Cretaceous.

In his presentation, Dr. Brown discusses the discovery, collection, preparation, and current research about this one-of-a-kind fossil. Find out how this specimen has added to our understanding of the evolution and ecology of armoured dinosaurs.