Before Ankylosaurs, There Were Aetosaurs

morning everyone it's 11:00 so we'll get rolling welcome to today's installment of the Royal Tooth tiro Museum speaker series this week the museum it's cooperating Society are happy to present dr. Andrew Heckert Andrew grew up in Ohio where he obtained his undergrad degree from Denison University in Granville in 1993 he moved to New Mexico where he completed both his master's in his PhDs at the University of New Mexico and Albuquerque since 19 or since 2005 sorry andrew has been based at Appalachian State University in Boone North Carolina where he's an associate professor in the Department of geology and the director of the McKinney geology teaching Museum dr. Hecker its research program focuses on the vertebrate paleontology and stratigraphy of the American Southwest he's collected fossils ranging in age from the Devonian to place the scene focus primarily on Triassic strata of Texas New Mexico and Arizona and today Andrew is going to talk about one of the most iconic of Triassic vertebrates I eat asuras which is also a really fun name to say and so Andrew you want to enlighten us on these critters thank you very much [Applause] hi there everybody hear me okay it's excellent thank you very much for having me here and yeah I know I talked a little about it I eat a SARS and where you guys are of course you're very familiar with thank Kyla SARS and but before they were in Kalos ours that were a you to SARS or as those of us in the Triassic like to think of it as there were 82 SARS before there were and Kaila SARS so before I really get rolling of course I mean what I'm going to talk to you guys about is an array of things topics that I've collaborated with a number of people on over the years SARS honestly started for me as a bit of a hobby project I was doing a master's on micro vertebrates my advisor Spencer Lucas had some fossils he's like oh you should describe these or whatever so they began as something that I was doing while trying to accumulate some micro vertebrate assemblages and so I've worked with a wide range of people some people also in North Carolina I was happy to move to a state that also had Triassic deposits Argentine colleagues German colleagues my students have been have helped me collect a EDA SARS and from the American West for the last 10 12 years in Devin Hoffman who's now at Virginia Tech has been extremely influential will show some of the work I've done with him before my programs have always been very well supported by volunteers in the Mexico Museum in particular basically we were understaffed and so everything the collection the preparation the collections everything was very much a volunteer powered endeavor and of course have been to fortune to have some funding from a variety sources and thank you guys very much for bringing me up here so what is an AE - sorry I hope throughout this talk to try and answer all the journalistic questions if you are well what is what is the thing who studies it when did they live where did they live what do we know about them and because not infrequently when I've had an article come out on AE 2 stars I've had people or those related to ankylosaurus or those seen at one yeah well they are related day in Kyllo stars but so crocodiles or you know so are we for that matter right I mean we're all related but they're not closely related but they are these you know heavily armored animals with a carapace if you will made of variety osteoderms this is me in Argentina with a very not relatively correct this is a 1960s vintage reconstruction but I like it because I mean aside from being sort of reminiscent of the Crystal Palace it also it gives you some indication of the size exams they're not particularly large animals there were some much larger ones and there was a big set of Triassic arcus our reviews published in 2013 that I was happy to be a part of the etus are one and so here's a list of authors and most of us have been on most of the literature on ADA stars that's been published in the last couple decades one or the other of these authors oh okay so the Triassic more and more as we as we find more and more Triassic animals around the world we find out that almost all the cool things that crocodilians and/or dinosaurs have done some Triassic animal did something sort of broadly similar to that before from things that have been known for almost two centuries now like phytosaurs which gavial searched sort of resemble these other crocodilians and of course Temne spinal and fib Ian's had had these kind of long-snouted things long before they eat of stars have actually been known I'll show you for about a century and a half now a little more and then lots of other things that we think of as sort of classically dinosaurian or things like losing all the teeth and your snout putting a big sail on your back there was just a recent paper published about how this rouse okyun called Smok may have engaged in Tyrannosaurus like Ostia Fiji there's this very weird animal called tri optica that sort of looks like its skull is reminiscent of a Pachycephalosaurus now in the Triassic so there's all kinds of things happening in the Tri ass I'll be at a much smaller body size and usually in a different non dinosaurian lineage but that are still reminiscent of things that we see later on in in the Mesozoic but AE to stars in particular are having long known and they do superficially resemble and Kaila SARS or Inca visage superficially resemble them Boatright both heavily armored animals oftentimes with lots of spines laterally I will show you some illustrations of how I eat a SARS may have had somewhat weaponized tails or at least invested heavily in protecting their tails and so on so just you know you can read all these highlights there the armors are distinct on the other hand when Zia Pelt ax this is a day in kailua Sergio Pelton and when this was published I was just fascinated with that because it's like I think I published a very very similar figure just a year to ago now the scale is entirely different Legos are wonderful metric tools here so that's a 5 centimeter scale there so that that specimen is only a few inches across whereas a you know this is almost a foot you know 30 centimeters just in this vacant space here but these are both neck ring cervical rings of these two not at all closely related animals they're very very convergent here and there's actually a fairly good diversity of ATIS ours they they come in a variety of body forms they're all quadrupedal they've been found at varying sizes these are almost surely juveniles but there's still some specimens that we think are barely over a metre long total body length whereas there's a giant individual of this animal that was pretty surely 6 meters or more long so very large by the standards of the Triassic anyway animals and a fair diversity of of body forms about 25 or so general that we all agree on give or take 30 or so named species when skulls are very uncommon Aveda SARS they've not been found often and when they have been found they're often not well preserved but when you see them there's clearly there's some diversity here to that we need to explore better and some of my colleagues are working on this they're not all doing exactly the same thing incidentally the name I eat asaurus comes from the Germans who named it it was name that was meaning eagle lizard and that was named for eat asuras here which had a really narrow pointed snout which is actually pretty unusual most other ADA czars have this slightly expanded snout here they may or may not have teeth at the very tip of the snout you some of them have essentially lost all their pre maxillary teeth others have a more complete dentition so they're doing a variety of things whatever they're doing it's not just one niche that they have occupied through geologic time so fundamentally to understand an AE to star in the way I got into them is that they are heavily armored animals and effectively what you have is you have columns of armor and I was just talking with Caleb here earlier and we both kind of stumbled upon the same idea right yeah this grid and you have to come up with some way to describe it and we both decided independently for him for notice ARDS myself here for a you source that you wanted to have the things that parallel the vertebral column let's call that a column and then we have transverse rows and with a eita stars they are very definitely associated with the vertebral column so that essentially every row of osteoderms is matched up with a vertebra there's some funny things that happen later on in their evolution up in the neck but basically you have a pair of median asti dermal left and a right and then a lateral osteoderms a left and a right that extend from the skull all the way to the tip of the tail some ae2 stars then also have a ventral carapace which actually can have quite a few rows of more square osteoderms and then many but perhaps not all had an in brocaded seta armour Asha green of armor covering the limbs all of this means that there's a lot of possible fossils to recover these are fairly durable and so and you hope to show you they they have a lot of distinctive features that have allowed us to in many cases identify as ours from relatively sparse remains in fact there are many taxa where all we have is their armor and that but we've still successfully demonstrated that it's a different tax on than any previous one so they are known solely from their armor okay so again a variety of body plans some of these guys are very wide bodied some of them are very spy knows does Matt asuka's is probably the most famous a you saw it with had a role in walking with dinosaurs and some other shows and with its great big shoulder spines is very distinctive it's been known for some time this is to date about the only Northern Hemisphere reconstruction of an ADA sorry that's really on display this is in Stuttgart and this is sort of the please amorphic or the basal ada star pattern which was a lot of armor that was not particularly spy knows but just a series implicated plates and diversity of a eunice ours is sort of mixed between all of those different body forms there's no real distinct trend in their evolution so where do they fit in the in the general family tree of ARCA stars they are on the crocodilian line here so so again not at all closely related ankama stars by any stretch and phytosaurs those superficially crocodilian Triassic reptiles have been various recently some people have found them outside of this line that's now called pseudo sukhiya others you know traditionally they were usually recovered as Justin's they're so depending on where phytosaurs are they eat a surgeon one of the earliest branching one of the more basal forms of the crocodile line arcus ours okay so I actually kind of prefer I found this chart and somebody's progress report for a European project by actually kind of partial to this diagram because it gives you a little bit more indication of especially in the Triassic this variety of different things that are happening and different of these lineages doing things that were eventually mimicked by dinosaurs but again you see that the euro SARS are down here very near the base of the the crocodile line split and therefore not particularly closely related to dinosaurs like anything we could we've done many phylogeny x' of these things way since ever since computer assisted phylogeny reconstruction has been a thing we have been trying to do this there are some real challenges here not the least of which is while there's a lot of information in the armor and there actually many characters scored for the armor because there are some taxes such as a cane asuka's here georgette asuka's that are really known only from armor unfortunately there are other taxes such as edo bar back annuities and to a lesser extent paulson asuka's which have essentially no arm are preserved with them most of the skeleton is other parts and so by definition those are always going to be ambiguously related as to each other but so we're still in a state of flux if you've watched a ATIS our trees develop over the course of the last couple of decades they've taxa have migrated around quite a bit within the trees and also you'll see that for those you deal with these kind of things there's nothing really strongly supported there's relatively few things other than all of these are wide bodied animals these are the very spy knows animals they are probably pretty closely related but we just do not have a great handle we need more and better fossils of these things so again there seems to be a clade that's mostly wide bodied animals some a clade that's a lot of fairly spino animals but that there are pleasee amorphic animals also spread throughout the tree when did they live there Triassic animals they're actually exclusively Late Triassic animals and if I can give a little plug for the Triassic here if you've not been watching the Triassic time scale for the last couple of decades one of the things that has become eminently clear is that of course it was originally subdivided based on fossil occurrences and it's effectively ammonite evolution and it was divided into a series of zones based on on various Triassic ammonites and then now that we've finally been able to find and and refine these these correlations and find beds that are dateable within there one of the things we found is that while the our knowledge of the Triassic is it's been about 50 million years long throughout the entirety of my professional career but one of the things that's become increasingly apparent is that the Late Triassic is actually the majority of Triassic time and that immediately after the perma Triassic extinction event these evolutionary rates must have been quite high and so the early triassic and the middle triassic actually occupy relatively small amount of Triassic time there are a you know stars known from the car nyun there's not any thing that's clearly a middle triassic and you just our ancestor but they probably they should be extend back further into the record but effectively ADA stars live during this last 30-some million years of the Triassic so at a respectable career they they lived for a good thirty million years the oldest ones are known from South America there are very young ones known from North America and if we look there's the Fulani like say is in such a state of flux I felt no scent and there was no sense in making it really time calibrated because I feel like the branches are going to move around but what you will see there across the top is that I just put a bunch of ends and C's and a couple ours which is is the taxon Orion is a car or is it Rison and the take-home I want you to get from that is that there must have been a quite a bit I mean some of these fairly derived taxa are actually very early appearing so whatever happened in the carny and are presumably before this there was a fairly explosive or rapid radiation there fairly extensive diversity and then some of these taxa actually you know there's fairly please amorphic ones still show up some of the very last AE desires are still you know scattered across the tree so they appeared they were fairly diverse at their first stratigraphic appearance and they remain fairly diverse across the entirety of their 30 million year career there are no jurassic a you two stars there's not even any candidates for jurassica etus ours the the latest Triassic record of terrestrial tetrapods is not as good I think as some other people would like you to think it is they definitely go extinct very late in the Triassic to the extent that that extinction is catastrophic across all tetrapod clades I have some misgivings up because they are clearly there are far fewer reach an AE to stars than there are norian although again the norian is hugely long and a lot of these taxa turn over so they're not all there for the extent of the norian but in any case rapid diversification and they stay relatively diverse throughout their geologic history of course the Triassic is the time of Pangaea and Ronde Blakey is well known for making these beautiful images of what hypothesized configurations of Pangaea so here is here's North America for scale and AE to sirs are known through Macross a great deal of Pangaea so if we look at it as sort of a more academic fashion right there's this is from our review in 2013 and you see that there are ADA stars scattered across Pangaea a few telling things it's there are none from Thailand and there's rocks of the appropriate age but the record there is not fantastic curiously there are no eaters there no phytosaurs either from South Africa and we have upper Triassic rocks in South Africa and so you would surely think that with a etus ours and Argentina and Brazil that South Africa would also be a possible place so there's some kind of curious thing I don't know why we do not have a you two stars from South Africa knowing where I am I thought I did checked with Han soos on on Sunday cuz I had and I had forgotten that they had published this paper so this is the Canadian record of a etus ours at time present there are a few oscillated osteoderms from the Triassic deposits around the Bay of Fundy in Nova Scotia so unfortunately there's very there's essentially no Canadian record of a etus ours on the other hand the next person who finds a decent ADIS are in nova scotia we'll have the best canadian ADIS our fossil because this is that's literally yet so but I mean and you do have Triassic I'm not sure how much of its upper Triassic marine Triassic in British Columbia and so you can always hold out hope that you'll have a borya Pelt alike occurrence of some ae2 star drifting out into that sea sometime unfortunately these osteoderms are not very distinctive at all there's a pair median of ntral there's really not much that we can say about those a osteoderms one fun thing about studying Aida stars is that a variety of very famous paleontologists have at least touched on them the original once tagging olympus was found and are described by Louie Agassiz he was under the impression that it was from the old red sandstone and so he thought that whatever this was was one of those Devonian fish so it got the name stag on a Lepus robertson eye we now know that is of course not Devonian and in fact this other fairly famous gentleman a guy named Huxley poker ected Agassiz in 1859 and 18 seventy and showed that those are actually from the new red sandstone Triassic deposits in Scotland the us bone Wars of cope and marsh heaters did not escape from that cope actually had the more useful contributions I guess I would say he you know he's named he named a couple attacks both of which are valid at some level still today he found named type of thorax specimens and he also named something that includes what we now know as des mat asuka's Marsh describes some fossils from eastern North America and because these German individuals the Fras had described a survey then he did coin the name a etus aria the frost specimens are includes some spectacular specimens this is in many ways one of the most impressive 82 SAR fossils you can stumble across this is a lithograph and then this is a reconstruction of the block and the astute of you have already seen my my lego scale bar here so this is just two inches across here so there's twenty some individuals on that block it's a stunning specimen unfortunately having been discovered in the 19th century and prepared in the 19th century it was prepared without benefit and magnification really they did not use microscopes when they preserved it and so it's not once you get closer to it it doesn't always get to look that much better still it's a fascinating very interesting thing I was fortunate to study it again last year here in Stuttgart and I mean obviously we are in a world-class Museum here there right where we're standing right you guys have amazing collections and amazing exhibits but I do have a soft spot in my heart for when the Germans decide to collect something they really go all out so this is one side of their oversized collection here this is a cell phone panorama obviously so here's my dual desk for the week and that a etus our block and the thing I haven't read way back there at the end yeah that's a Megalodon that's a giant shark yeah cooler down there I mean this is you norm all these are basically these are all the ichthyosaurs but they had stumbled across some au to stars and they're happy to let you work on them other famous early 20th century paleontologists Frederick Brown hyuna very famous for working on dinosaurs and other artists ours he worked some on ADA czars principally the German and American ones so here's a image of him this is not an ADA czars mammal-like reptile the fellow named ermine Cal's case was very influential collected a lot of stars in Texas and collected the more iconic specimens of Desmet asuka's but they were always sort of an incidental you know each of these fella you know a paper a decade here they're on a eat a soars not well well understood and Josef Gregor Ebert was famous a Yale and Berkeley and this fellow Alec Walker is was hugely influential he did a dissertation on those old read Aida stars and so and really let well illustrated monograph that came of it and so much of the kind of you know he sort of set the standard for what everybody thought of as that you to sort of sort of the first modern reconstructions things that look like this so you see that I mean that looks pretty similar to all the reconstructions I've been showing you so he was known for just a handful of monographs as really his contributions so the really important thing in the terms of the art of ADIS our studies is this paper in 1985 where a couple researchers associated with the university of california berkeley published about the aegis or osteoderms from Petrified Forest National Park which is entirely Triassic rocks and has several superposed assemblages and if you're into paleontology at this time right and we're just starting to get the capability of doing phylogeny x' by coding characters with zeros or ones a table like this and you're like oh that could be turned into a bunch of zeros and ones and we might be able to just from osteoderms be able to say something about the relationships of these animals and of course it's also the Avenue yeah this is when we're moving from typewriters to word processing and spit the pace of scientific discovery and description can really pick up so if you look at today okay here's a relatively recent Falah Janee and the starred specimen the yellow stars are all things that were known in 1985 and had a name in 1985 the orange stars are things where the specimen was known or had been described or somebody might have been kind of playing with it but had not actually been named and then all the other specimens have been named since then and then in part like I said some of them just because the armor is relatively distinct between several different taxa so we've had an explosion in the last twenty years thirty years really the last thirty years of going from maybe a dozen or so named genera to better part of 30 actually not all of which are good enough to include in an analysis like this but fundamentally this explosion ties directly back to this realization that the osteoderms are quite distinct if you're willing to reduce and detailed nitty gritty work with them so my training is principally geological I I'm really a geologist at heart my degrees come from geology departments essentially but of course the the paleo biology of an animal is a fascinating thing and I've you know so I like to kind of play with it and try and figure out as much as we can so I'm going to show you here in the next little bit just some of the things that we're thinking about a eat of stars right now and what we understand of them so things about how they may have moved their trace fossil record their diet how they grew maybe even a little about metabolism here so here's a much this is a much more recent sculpture from in Argentina at their tall and Pasha park that's an animal called Nate neo you too sir ladies okay articulated a you two star fossils remain very rare frustratingly so but when we do find them I mean even here there's barely enough to get digit account so if they offer each finger but fundamentally they do if you if you do what we call the Cinderella method of does the does the foot match the footprint kind of question particularly nice specimens like this one that was found by a volunteer Scot Sucher who works with me and New Mexico the beautiful thing about this is even though it's articulated the feet were found sort of flip-flopped so you can see one in Palmer view the underside you can see the other one in the dorsal view so that you get a decent look at each one I mentioned for Darrin actually here there's one of them the one metatarsals a couple centimeters shorter than the other I think it was compressed and fractured or something so but I mean articulate skeletons are great to work with although they can also be challenging but at least we got good feet out of this so we can make a fairly convincing case I think this is a piece artwork by Matt Zaleski and of all the things of his that I managed to put a tagline on I failed to put it on this one but trying to show what we know of that specimen and the footprints it would make there's a Triassic track called Brockie kyra theorem that is widespread throughout Pangaea and deposits and it seems to match very well with ae2 stars they are not exclusively to ae2 stars but but it certainly matches very well with a e2 star footprints this very small 4 foot impression a much larger pest impression and it seems to match well with our reconstructions of that animal also fairly upright animal especially here in the hind limbs the hind limbs I think have to be very much pillars beneath the body the four limbs probably more sprawling but still able to kind of swing around and leave these small impressions just outside of the back limbs so we have some thought that these have at patient's that suggest that maybe they were they could dig that you know they have basic limb proportions this is a recent article on a Polish ASR here's another specimen from New Mexico a relatively complete skeleton although this one lacks much the forlán but fundamentally the limb proportions are similar to that seen in modern animals that do that do a fair amount of digging there's some thought that maybe that expanded tip of the snout also helped it do a little bit of digging there they're fairly stocky animals as it was so the robust muscle attachments you could argue or maybe just because you're carrying all this armor around but there's also the proportions are similar to what we see in a variety of digging animals today so there's some thought that whatever they were doing they may well have been adapted for digging they don't have like if you would consider 10 or 12 adaptations of classical of diggers they don't have nearly all of those but they have six or seven or so again like I say the skulls fairly diverse they are on the crocodile line you see that the teeth tend to be pointed at the very least and various people have over the years hypothesized all manner of dietary niches for them this is a wonderful German specimen of an animal call of a need to start called para type of thorax and you see that the teeth don't really look like a plant-eating animal but they don't really let you look super predatory either and certainly this is a very this is not an animal that's chasing down much of anything so what exactly are they eating it remains up in the air and certainly there are different taxa must have been doing different things I have colleagues who have argued that some tacks have greater bite force that others have a little bit more I seem to have more of a bite higher bite speed at the expense of bite force and so there's some thought that maybe these things were rooting around and eating insects or other things and in tree trunks and rotten vegetation and so on it's just it is very enigmatic because that sure doesn't look like a great dentition for eating plants but the body doesn't look like it should be a carnivore a predator of any sort so whatever they're doing it's an unusual niche and many of these Triassic deposits they're the only reptile that even looks remotely herbivorous so it's always been sort of assumed that if you have any sort of food web at all that these are the herbivores in that food web but there it really honestly remains somewhat enigmatic I've had the fortune to travel to Argentina work with some Argentine colleagues and this is a specimen that will illustrate some of the joys and frustrations of working with an Aes are they are extensively heavily armoured so that's cool it protected a great deal especially on the other hand finding the bones is a challenge that they're almost completely covered by the osteoderms in some places and so this is really just sort of the back end of 182 SAR but it has some important paleo biological implications I think so here's sort of a draft of what we what we're thinking about it oddly enough I mean I don't know how much you can do with it but you can actually find Walker had found the cloaca vent in a in stag and Lepus we can see it here in this specimen of possibly an animal called a eat a thyroid ease it's a fairly broad opening actually within they eat asar and so of all things I am the world's expert on ATIS or cloaca vents because we had also found this in type of thorax and an animal called coho masuka's the one a type of thorax is actually quite fun because if you notice there's a bunch of spikes around these Austin earns and these Austin IRMS had been found loose previously and thought were thought to be part of the side armor and when I found them on this one specimen I said I knew it was like oh we have this other specimen please please please don't have the spikes around the cloaca vent because it's gonna be really exciting if we've got some sort of sexual dimorphism here based on the spikes but sadly the other specimen has the spikes too so I don't know what that says about type of thorax but they had a spiked cloaca than some other things that are kind of cool about some of these specimens is here's this Argentine specimen again and this is the ventral armor and you can see - nice columns and then starting here they actually are fused together and many of these osteoderms usually on the dorsal series it's a little easier to tell they have what it's called the center of ossification now and that does seem to be what it is it's where the where the bone first starts to ossify and so these are sort of Casa fide and fused together and so then if you section these your best chance of getting an archive of the of the animals growth is to go right through that center of ossification or very close to it and you'll actually get these these lines of arrested growth essentially the tree rings analogy if you will of how the animal grew and also it shows that on you know venture caudally on this animal it actually viewed these Austin dinner now one thing that has changed over the course of my careers when I started we were very you know very enthused about being able to tell eat us our osteoderms apart by characteristics of their ornamentation and other features and now when you like many things in science when you really dive down into it start getting an itty gritty details you start to find things that make you less certain of what you thought you knew so these are all examples of the lateral side of these para median osteoderms this is some work I did with Huli de Soho and her student here Aeneas Tabora de and he did a wonderful job of point out we had always described this animals osteoderms as having a fairly radial pattern and yet there were clearly differences between this radial pattern and this radial pattern and he eventually called this a nasty moseying after the pattern of the the ridges between the pits and grooves and sure enough if your number is relatively narrow it's a nasty Mozang and if it's much wider proportionately it's much more radial and stretched out in a long gait and I'm quite certain this is God a lot to do with the growth pattern of the animal itself and there's a variety of histologies who have worked on crocodilians who are kind of showing broadly similar things so whoops I did I do so here on the medial side much more in esta moseying this more rapidly growing lateral side much more radial and I think that has some implications for how much we really can do with some of the ornamentation so briefly a couple of the things that I've done more recently I was fortunate to move to a state that had a you to serve fossils this one we named gorget asuka's shortly before the appellate uh the name comes from the medieval knight scholar the gore jet here's our cervical ring if you will there's some properly attributed Matt Zaleski art and so this is an example of a specimen where that was what it looked like when I got to Raleigh and I had seen some very spiky armor of type of thorax and I was like oh you guys have a tail of an Aes R and then as they continue to prepare it out we realized oh no that's a neck and even though we only have the armor that armor is distinct for any other specimen so we were able to name that animal a few years ago there's our neck ring collar so even though all we had was really about 20 or so osteoderms there's various features of it that are distinct that from both longus suka sand Luke asuka's here is a couple contemporaneous animals another specimen that we had and here's where I was able to name this thing but then my student Devin Hoffman did his senior thesis doing some other things with it this is a relatively small specimen only these scale bars are probably 5 centimeters long a little roadkill specimen we call them as smash skull smashed armor here's the ventral side and again the huge challenge with these things is that you have a whole lot of armor covering the body so we get we did get a cat scan we had relatively limited its success with the CT scanning but we were able to find Devin was able to segment out and find a few more elements that we knew were there unfortunately these Triassic rocks in North Carolina they've been buried quite deeply they're not technically metamorphosed but they're getting close and so the density differences between the armor on the top the armor on the bottom the bones inside and the matrix are made this project very challenging but one of the things we're also able to do is section some of these bones and get an archive of the lags here so these are the lines of arrested growth in some of the osteoderms or here in a radius and generally speaking we were far from the first people to look at it as ours and document lags and so on but generally speaking one big difference between them and the end kyocera's they're slow growing they are for the most part not fast growing animals 2 meter long a yes are there are 2 meter long roughly individuals that have 20-some lags in them so they were over 20 years old because these are the essentially the lines that form every time growth truncates during a slow season a winter or dry season yet we were able to show that this juanita Sarkoja masuka's appears to be growing relatively rapidly okay so these specimens are all roughly equivalent in size this one actually has the widest osteoderms yet only has one or two legs whereas this one has five or so so it was clearly at least six years old and this one was perhaps 10 years old and so there seems to be some diversity in their growth pattern I feel like this is fairly we've demonstrated this fairly conclusively and interestingly now Cole masuka's one of things that makes it distinct is that the patterning on the armor is extraordinarily faint so you basically cannot see it in this picture but it's these very very faint grooves and ridges right along here well this is also the most rapidly growing of the specimens so to me it's not actually terribly surprising that it emulates this very radiant pattern but it's actually growing perhaps so rapidly that it's just simply not depositing the thicker ridges on on the bone so I have another colleague who sought me out who's actually very interested and their metabolism and reconstructing metabolism is of course very challenging especially when you have an animal that's low on the crocodile branch and some people have argued that all arcus ours would have started off you know that a high metabolic rate is ancestral for our kesariya and that modern-day crocodilians have lost that and there are very good reasons for that argument I'm I'm relatively partial to that argument on the other hand there's very little about a etus ours that looks like their high meta meta thought great animals so here we are in the process of doing a variety of things and trying to look at this and he's got a very complex data set but fundamentally trying to look at extant animals and model what a you to search might have done of course the actual mass the animal is the most important variable as far as how much it it burns but then other things you know comparing it to other largely endothermic animals to try and see where they might fly fall out how crocodilian or turtle-like might they be and finally on kind of a lighter note this was my my this is a part this is the one of cover photos I provided for this and they're not dinosaurs they eat a serves don't show up in artwork there is no town which has a etus or fossil or etus are reconstructions distributed about the town so right but this is a very interesting amount of para type a thorax in Stuttgart and the preparatory did this also all those welds are individual welds he spent quite a bit of time tacking this thing together and I rather like I kind of like this helmeted night look of the thing and so one of my colleagues at Appalachian Lauren water worth she dreamed up she's like well yeah we don't have an exhibits department because we're a university not and we have a very tiny little Museum but we do have an art department and so she worked with us artists and art department Travis Donovan and they came up and they sculpted his class sculpted a life-size model of our friend gorget asuka's taking it from Matt Zaleski artwork turning it into a three-dimensional thing there's a variety of fascinating tools involved with this and then putting plasticine or making plasticine and putting it on over it and developing an animal that they now call Archie because I kept hearing about arcus ours so that is a life-size model that we are hoping very much to get installed as a bronze on campus here in the relatively near future so in conclusion you know if you know about it you just artists that are actually you know relatively well known we've known a you to star fossils since 1830 we've known that they were crocodilian relatives since 1859 yeah there's their record is not great and we don't fully understand what they were doing biologically we don't fully understand even how exactly they're related to each other what their metabolic rates and were etc and so there's a lot of things I think that we can still do with these animals we're really just beginning to get a grasp of their diversity and so their extended paleo biology is something that we still have an opportunity to do a lot of things with going forward so with that thank you very much for your attention and I'll be happy to answer questions you

Channel: Royal Tyrrell Museum of Palaeontology

Views: 18,665

Rating: 4.9443154 out of 5

Keywords: Speaker Series, Royal Tyrrell Museum, palaeontology, paleontology, aetosaur, Triassic Period

Id: 3d3cgO3EZYc

Length: 44min 59sec (2699 seconds)

Published: Tue Mar 12 2019

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Dr. Andrew Heckert (Appalachian State University) discusses how aetosaur discoveries from the last four decades have given us new insights into these animals.

During the Triassic Period, before ankylosaurs appeared, aetosaurs were the evolutionary prototype of the heavily armoured animals. These “crocodile-line” reptiles are known from late Triassic rocks from across much of Pangaea . Like ankylosaurs, aetosaurs were covered in armour, with hundreds of overlapping osteoderms arranged in two columns on the back and sides of the animal. Most aetosaurs had additional armour on the underside of the body. Adult aetosaurs were typically 1.5 – 2.5 metres long, but exceptionally large individuals may have reached six metres.

Many famous early palaeontologists worked on aetosaurs at some point in their careers, but these animals have remained relatively obscure for 150 years. Scientific understanding of aetosaur palaeobiology remains in its infancy, and details of their diet, origin and development, locomotion, and metabolism remain elusive. Largely considered herbivorous, it appears that some aetosaurs may have been insectivorous. Histological studies often indicate slow growth, with adult specimens older than 20 years old. Dr. Andrew Heckert will discuss how aetosaur discoveries from the last four decades have given us new insights into these animals.