11-Extinctions: Oddballs of the Triassic

Hans Sues is a fossil guy at the Smithsonian. Born in Germany, he has been all over the world finding and interpreting fossils for more than 40 years. His focus is on vertebrates – both in his professional work and his personal attachment to cats. We talked with Hans about why the Triassic era had so many strange animals, what happened in the extinctions at each end, and why he worries about getting arrested while doing field work.

This episode was produced by Devin Reese and mixed by Collin Warren. Art, editing, and production assistance by Jace Steiner.


Shane Hanlon:              00:00                Hi Vicky.

Vicky Thompson:           00:01                Hey Shane.

Shane Hanlon:              00:02                Have you heard about these giant spiders that are coming to the DC area?

Vicky Thompson:           00:08                No, no.

Shane Hanlon:              00:09                No?

Vicky Thompson:           00:09                No.

Shane Hanlon:              00:11                Oh goodness. This is so exciting.

Vicky Thompson:           00:16                What is this? Giant like tarantulas?

Shane Hanlon:              00:16                No. So they’re called Joro spiders, J-O-R-O spiders.

Vicky Thompson:           00:20                Spiders.

Shane Hanlon:              00:22                I just did a quick Google search and there’s there’s headlines like “Giant spider heading to the East Coast. It’s good news for agriculture.”

Vicky Thompson:           00:31                Oh.

Shane Hanlon:              00:31                Joro spiders likely to head beyond Georgia. Yeah. They’re going to be coming to our area.

Vicky Thompson:           00:35                But they’re already in Georgia?

Shane Hanlon:              00:38                Yeah. They’re going to be everywhere. Let’s just put it that way.

Vicky Thompson:           00:43                So, okay. So I feel like murder hornets. There was a lot of hype around that. But then I never, I luckily, I feel like at least in my personal life, never saw much of a murder hornet.

Shane Hanlon:              00:58                Yeah.

Vicky Thompson:           00:59                So I’m definitely going to see these spiders?

Shane Hanlon:              01:01                Almost certainly. Yeah. So the murder hornets were out West.

Vicky Thompson:           01:04                Oh.

Shane Hanlon:              01:04                And they’re actually really bad.

Vicky Thompson:           01:04                Okay.

Shane Hanlon:              01:05                Murder hornets are really bad. They’ll mess your day up.

Vicky Thompson:           01:07                Yeah.

Shane Hanlon:              01:07                The Joro spiders are big. They’re about the size, like with legs and everything, they’re about the size of your hand.

Vicky Thompson:           01:12                No.

Shane Hanlon:              01:12                Like a part of your hand. Yep. But they are venomous, but they probably won’t hurt you. But I think we’ll have to add some addendums to this. I think they like fall from the sky?

Vicky Thompson:           01:28                Okay. You said, “but they are venomous.” Like you’re supposed to say, “but they’re not venomous.”

Shane Hanlon:              01:33                I mean-

Vicky Thompson:           01:34                And they don’t fall from the sky.

Shane Hanlon:              01:36                Are venomous.

Vicky Thompson:           01:38                I don’t like anything that you’re saying.

Shane Hanlon:              01:41                They balloon, they don’t parachute. Yeah. I’ll just send you some articles. It’ll be really great. We’re going to learn some things about ourselves.

Vicky Thompson:           01:48                I’m not reading them.

Shane Hanlon:              01:48                No, it’ll be fun. So last year we had the cicadas.

Vicky Thompson:           01:50                Yes.

Shane Hanlon:              01:50                Which were just more annoying than anything.

Vicky Thompson:           01:52                Those were fine.

Shane Hanlon:              01:52                I think my phone was actual ground zero. This year we’re going to have spiders.

Vicky Thompson:           01:56                Okay. I can’t. I need to leave the area.

Shane Hanlon:              02:00                It’ll be fine. We’ll get through it, I swear.

Vicky Thompson:           02:02                Okay.

Shane Hanlon:              02:02                All right.

Shane Hanlon:              02:07                Science is fascinating, but don’t just take my word for it. Join us as we hear stories from scientists or everyone. I’m Shane Hanlon.

Vicky Thompson:           02:16                And I’m Vicky Thompson.

Shane Hanlon:              02:18                And is this is Third Pod From The Sun.

Shane Hanlon:              02:22                So, Vicky, you’re not stoked about this. Did I just ruin?

Vicky Thompson:           02:25                No.

Shane Hanlon:              02:25                I ruined your day.

Vicky Thompson:           02:26                I’m not team spider.

Shane Hanlon:              02:28                Yeah. Well, I mean like a little bit of more reading. Yeah, venomous, but probably won’t bite you and if they do, it’s no worse than any other spider bite, which is still pretty rare. There will be a bunch of them, unfortunately. So look out for webs and spiders, like big honking spiders at eye level.

Vicky Thompson:           02:46                Oh.

Shane Hanlon:              02:46                And it’ll just be something that we all, it’ll be a shared experience, Vicky. Life is all about sharing experiences and we can share in this together.

Vicky Thompson:           02:54                Yeah. Something to look back on. Okay.

Shane Hanlon:              02:58                So we’re talking about those huge spiders coming to DC for a reason, not just to freak people out. Today we’re going to be talking about the emergence millions of years ago of a pretty diverse group of animals that don’t actually include spiders. To tell us more we’re going to bring in producer, Devin Reese. Hi Devin.

Devin Reese:                 03:18                Hi Shane.

Shane Hanlon:              03:19                All right. So before we get into it, what are your thoughts on the giant spiders?

Devin Reese:                 03:24                Yeah. Even as a biologist, I am not sure I want to have one of those crawl on my face.

Shane Hanlon:              03:32                Yeah. Biologist here as well and I personally agree with you. But luckily we are actually not here to talk about spiders. What are we here to talk about?

Devin Reese:                 03:42                Today we’re going to hear from Hans Sues who’s going to tell us about the geologic period called the Triassic. That’s the one right before the Jurassic. So the Triassic started like 252 million years ago and ended about 201 million years ago.

Vicky Thompson:           03:58                Okay. So for reference, this is like Jurassic Park but earlier in time, so Triassic Park.

Devin Reese:                 04:04                Well, Hans is actually the best person to answer that question, but I’ll give you a hint, which is that dinosaurs showed up way before the Jurassic, along with a lot of other weird creatures.

Shane Hanlon:              04:16                I mean, okay. In all fairness, I think T-Rex’s are pretty weird with like their big heads and their little hands. I’m miming. I wish people could actually see this right now. So I’m really stoked to hear this. Let’s get into it.

Hans Sues:                    04:29                Hi, I’m Hans Sues. I’m Senior Scientist in the Department of Paleobiology at the Smithsonian’s National Museum of Natural History.

Hans Sues:                    04:39                And I’m in charge of non-vermilion vertebrate fossils.

Devin Reese:                 04:44                And we’re going to be talking today about a particular era, about the Triassic. Do you specialize in that era or do you work across?

Hans Sues:                    04:56                I became interested in the Triassic that in group after group that I looked at, the key events in the early evolution and sometimes the origination of the group took place during the Triassic. So the Triassic in a way is really the time that modern ecosystems and most of the dominant modern groups of animals on land and even in the oceans come into being. And so it’s a really interesting period. Strangely, however, when you do an interest scale for geological periods, the Triassic has gotten much less attention than a lot of other geological periods.

Devin Reese:                 05:33                And I’ve heard it described as sandwiched between two major extinction events.

Hans Sues:                    05:39                In that respect, it’s actually unique because it follows the largest extinction that we had in the history of life during the last 600 million years. And it ends with a major extinction of life, both in the oceans and on land about 200 million years ago.

Shane Hanlon:              06:01                So the Triassic started with the biggest extinction event in the history of life on Earth. We’re always hearing about the extinction of the large dinosaurs after the asteroid hit, but not so much about this earlier extinction.

Devin Reese:                 06:13                And this extinction that started the Triassic, it was more severe and it was a couple hundred million years earlier. So I actually asked Hans what changes did this End-Permian extinction cause?

Hans Sues:                    06:27                In the oceans, there was like an enormous extinctions. Many major groups disappeared. And by some estimates, anywhere between 80 and 90% of species disappeared. On land, the extinction was far less significant contrary to what is written in particular a lot of popular books. But the important thing that happens on land is that a group that are called stem mammals or therapsids, which were sort of the precursors of our own class mammals, they actually had huge losses at the boundary, particularly among their plant eating forms.

Hans Sues:                    07:01                And so as we go into the Triassic, the diversity of the group has been enormously reduced. And what happens at the same time is that true reptiles suddenly diversify like crazy. And since this is sort of the beginning, really of the Mesozoic as the age of reptiles. And along with this, and that’s sort of one of the fun things about the Triassic, is that there all these really strange and unusual animals that only existed during the Triassic and vanished at the end or towards the end of the Triassic. And so this is sort of an interesting biological conundrum. Why are they there?

Devin Reese:                 07:39                So if I were to go back to the Triassic, would I recognize any animals as representatives of the groups we see today? Would any of them look familiar to me?

Hans Sues:                    07:50                Well, there would be some animals, but I think the majority would be even from groups that are now still represented in our living ecosystems, many of them would look utterly strange, but you would see lizard like things you would see fish that you would recognize as belonging to major groups that are alive today, for instance lung fish, or little coelacanths.

Hans Sues:                    08:14                But then there are these other things like phytosaurs, even though they’re superficially look like crocodilians, when you look up closely you see this difference, particularly in the shape of the head. And then there are lots of things like the Rauisuchians, the heavily armored Hylaeosaurs, which were these plant eaters that had the entire body in this cuirass of bony plates. Those were all things that would be utterly unfamiliar, would be like, you might as well have gone to another planet with life. It just would be so utterly alien.

Devin Reese:                 08:52                So can you tell me about some of the odd fellows that you have discovered from the Triassic?

Hans Sues:                    08:58                Among the odd fellows, I have discovered there’s an animal called Teraterpeton, which comes from late Triassic rocks in Nova Scotia, Canada, and imagine an animal that has a very long, very narrow skull with a huge beak up in front, at least no teeth so it was probably covered by beak-like material, like in a bird, then two rows of upper teeth that are like little molar teeth including against one row in the lower jaw. A skeleton, that’s very robust, it has hands and feet with these enormous blade-like digging cross. And it is part of a lineage that existed during the Triassic called Trilophosaurs , and these animals were very diverse during the tri during the Triassic.

Hans Sues:                    09:47                I just found a new one from the middle Triassic together with a German colleague. So these animals were around for most of the Triassic, very, in some ways like trilophosaurs, the best known genus, is very lizard-like, in fact, I thought that they probably were like big iguana lizards that sort of clambered around in trees. They were all plant eaters. They had specialized dentition for just that. But again, you look at these and they’re just, while they’re superficially, perhaps a little bit like certain lizards, they’re just so generous when you look at the skeleton.

Devin Reese:                 10:22                So these things are like lizards with beaks?

Hans Sues:                    10:26                Yeah. They have molar-like teeth in the back and then beaks on the front of the snout. Then another bizarre animal, perhaps my favorite Triassic animal is called longisquama. It’s just known from skeleton, a partial skeleton and some impressions from the late Triassic of Kyrgyzstan in central Asia. And imagine an animal that looks like a little lizard has sort of a chameleon-like head. And then has these strange long scale-like structures running along the back. Each scale looks basically has the outline of hockey stick and some people think very feather-like, but it actually has more heft to it than a feather. And nobody even knows what it is related to. We know it’s a reptile. We can even say that because it has two holes in the skull on either side behind the eye socket, that is a diapsid reptile, the dominant group of reptiles, but there it ends.

Devin Reese:                 11:30                Okay. So you say the scales are shaped like hockey sticks, but are they cylindrical?

Hans Sues:                    11:36                Yeah, they’re cylindrical. They have this strange roughened surface with these little undulations running across it. And they obviously had some kind of spongy interior. It’s a little bit like on some lizards have, like for instance, green iguanas have these scales on their neck and back that are rather three dimensional when you cut them through the spongy tissue in the center, something like that. And what it’s there for is anyone’s guess. Initially somebody suggested that there were perhaps structures for gliding, but that’s not the case because there’s only one row of them. So you need two rows to have an effective sail. And also they weren’t in any kind of sense movable. They have soft tissue attachments to the backbone.

Devin Reese:                 12:24                Well, you did talk about experimentation. So glide, plop!

Hans Sues:                    12:29                Plop! There was one really interesting group that did glide very successfully. They’re called Kuehneosaurs. And they’re only known right now from Great Britain and from New Jersey. And, these animals are really interesting because they have these super long ribs that they could fold out and kind of like the gliding lizards of today that you find in south Asia, they were using them to support huge membranes along the side of their body. So these animals could actually glide. And of course, this is at the same time that you get also the first active flyers, which are pterosaurs, the group that includes pterodactyls.

Devin Reese:                 13:12                And you talked about the Triassic being fundamental in establishing the major groups that we see on earth today. So when you look back at the Triassic then, are you really seeing the beginnings of the reptiles and the birds that as you just pointed out dominate today, despite our mammo-centric focus?

Hans Sues:                    13:32                Exactly. Yeah. Basically when you think about important groups of animals today on land lizards and snakes first show up in the Triassic. Frogs and salamanders show up in the Triassic. The immediate precursors of mammals show up in the Triassic. Dinosaurs show up in the Triassic, and of course, dinosaurs are the lineage that includes birds. And so birds basically show up in the Triassic and so on and so forth. And among insects flies, for instance, a really important group of insects, first show up in the early Triassic. We have beautiful fossils to document that. Most of the modern groups of beetles show up in the Triassic, grasshoppers of the modern type and so on all of these things show up in the Triassic.

Shane Hanlon:              14:25                So many things that aren’t mammals.

Vicky Thompson:           14:28                Yeah. Mammals get all the love, no love for the other creatures, I guess.

Shane Hanlon:              14:34                Yeah. I agree with you. And especially selfishly as someone who studied frogs and turtles, I have a special place in my heart for the creatures that folks don’t always think about. But for Hans, in order to study all these different animals, he actually had the opportunity to travel all over the world.

Devin Reese:                 14:56                So you’re mentioning places all over the world. And so just tell me, in terms of your personal work, have you really gotten around the world to Triassic sites? What does your life look like in terms of your discoveries?

Hans Sues:                    15:11                Most of my Triassic work has been in central Europe and in the Eastern United States, but there’s, I have looked at Triassic deposits in Africa and Morocco, which is very well known for its Triassic rocks. And I’ve been of course out to the American Southwest, which for north American standards is sort of the gold standard for Triassic reptiles, places like Petrified Forest National Park. And I collaborate with colleagues in these areas, quite extensively. The other area that’s fantastic for the Triassic, but I haven’t done any field work in so far, is in Southern Brazil, the state of Rio Grande Do Sul. And then in Northwestern Argentina, and there you actually have layers and layers of rocks with different kinds of Triassic land vertebrates, various crocodile line, Archosaurs, the ruling reptiles, the first dinosaurs are known from south America and the list goes on. So it’s quite, quite interesting.

Shane Hanlon:              16:14                So Morocco, Brazil, Argentina. I like what I do, but I really wonder if I should be changing my job?

Devin Reese:                 16:21                Seriously. Man, I want to know if there are any Triassic fossils around here where we live.

Hans Sues:                    16:28                So for instance, if you drive through New Jersey, parts of Pennsylvania, you see these sort of dark or red rocks and if you go up in Connecticut, it’s all red in the area of New Haven, and those are Triassic rocks. And unfortunately they’re not as fossil rich as what we see in South America, but still they have incredibly good geological record. In fact, this is sort of slowly becoming one of the standards for measuring Triassic time because people, the researcher, particularly my colleague, Paul Olson at Columbia university and his colleague, Dennis Kent who’s at Rutgers university, has been doing this fantastic work, looking at changes in the Earth’s magnetic field, and then seeing how we can use that to date rocks because the Earth’s magnetic field every once in a while goes into reverse polarity so that the north pole becomes south pole and vice versa.

Hans Sues:                    17:21                Unfortunately, the Eastern US, even though I love to work here is a really tricky place to do field work because either people are sitting on it or it’s covered with vegetation. So in the American Southwest, it’s great, it’s all deserts. And you just, to your heart’s content can wander around and find fossils. But here, I mean, I’ve collected fossils behind the dumpster of him local McDonald’s. And in more than one case, I had a policeman asking me what exactly I was doing in a particular place because no one in their right frame of mind would be been looking at. And then I tell them, look, I’m finding fossils here. So get these puzzle floats.

Devin Reese:                 17:59                How would the world did you know, to look behind the McDonald’s for fossils anyway?

Hans Sues:                    18:04                Well, because that was the only outcrop in that area of Pennsylvania where the Triassic rocks were actually nicely exposed. It’s actually a historical site known since the 19th century, but, maybe 10, 20 years ago they put a McDonald’s right there because that was the place.

Devin Reese:                 18:20                I’m sure the cop was like, “yeah, right, sir”.

Hans Sues:                    18:25                Well, actually one of my colleagues who was quite elderly, there’s a very funny story about how paleontologists are treated by law enforcement, was looking for these tiny cretaceous invertebrates in Northern Germany, not too far, I should say, from a psychiatric facility. And they saw this old man crawling on the ground, picking up little rocks. And of course they thought, “Hmm, somebody must have escaped this morning”. So they arrested him and took him back and turned out to be this innocent professor from the local university. He was in his eighties by then, who was just collecting these little marine animals and had no idea why this was giving offense to law enforcement. So people always, when paleontologists wander around either they’re excited or they just get worried and you call nine one one.

Shane Hanlon:              19:17                Okay. So not in every case, but I guess this puts a different perspective on old men randomly wandering around outside.

Devin Reese:                 19:25                Right? Some of them may just be trying to get a window into the past, like way into the past.

Shane Hanlon:              19:32                And speaking of which, you asked Hans if he would take the opportunity to get a bit more than just a window into the Triassic.

Devin Reese:                 19:43                What if, in general, if you could be teleported, let’s say just for two days, two days and a night to the Triassic, would you go?

Hans Sues:                    19:51                Absolutely. But I would have to heavily arm myself. Because there were, Coelophysis was a predator and it probably would’ve been unpleasant in a way that the dog can attack you, but there were some really huge animals around there. There’s an animal group of animals called phytosaurs that are very superficially similar to crocodile, except they have their nose holes on top of the head, so basically sort of almost like a little U-Boat with a periscope. And there is a group of phytosaurus, a sort of subset that can attain enormous links. We have, there’s actually one on display now at the national museum of natural history called Smilosuchus, and Smilosuchus had a skull length of anywhere between a meter and a meter and a half, and that’s just the skull. So the whole animal would’ve been probably 10 meters. And it certainly would’ve been a more dangerous animal than any of the crocodiles dos that are alive today.

Devin Reese:                 20:53                Was there something that happened in the early Triassic that kind of got this burst of diversification going? Was there anything in the climate or the geology that got things kick started?

Hans Sues:                    21:06                No, actually it’s interesting. The early Triassic is a really bleak period in the history of life because you had this major extinction, but the other thing that happened during this extinction was because it was caused by the super massive volcanic activity, the climate was completely disturbed. So the early Triassic was a time when it was extremely hot and dry in many places around the world. So if you find life, it’s generally low diversity, not many species around. And we are still puzzling what happened next because as soon as you get into the beginning of the middle Triassic, there’s suddenly an abundance of animal and plant lineages. So were there perhaps refuge where things withdrew during the great climate crisis? Or were there just really fast evolutionary change events? And we still haven’t sorted this out because the problem is that the early Triassic is only known in a few regions of the world.

Hans Sues:                    22:11                And so we have a very biased picture of that. Like for instance, South Africa, where much of the Permian Triassic extinction discussion is centered for land life, the Permian is rich, diverse with particularly all these stem mammals and early reptiles. But then when you get into the Triassic, the first thing you find is this stem mammal called lystrosaurus and there’s very little, except lystrosaurus. Lystrosaurus is so common in South Africa you go out in a day and like in afternoon I’ve heard people finding 30 skulls of this, it’s almost like picking up potatoes.

Hans Sues:                    22:53                Just in Germany, I just recently discovered that we had the first Rhynchosaurs, which are these very strange animals that were very abundant in the middle and late Triassic of the Southern hemisphere, and the super continent Gondwana. And these were plant eaters and saw strange beak like-snout and then would chew up their plant food with these batteries of teeth, and an upper tooth plate, and then the lower teeth would sort of fit in like the blade of a pen knife into this upper, and they would just grind vegetation. They could eat the toughest stuff around the most fibrous vegetation. And yes, there were suddenly these little Rhynchosaurs in Germany where nobody had ever expected. And I’m just working on another animal with a German colleague, which is an early Archosaur-like animal again, something that we had no idea even existed.

Hans Sues:                    23:46                So paleontology is very incremental. We form ideas based on what we know, but then as good scientists, we keep testing these assumptions and hypotheses. And very often because of new evidence, we have to go back to the drawing board and come up with new ideas about what life was like at the time. So the question arises, how many groups actually did survive the End-Permian Extinction, yet left little or no record because that’s always the problem. Paleontology is sort of an exercise in serendipity because for large chunks of the geological record, there are very few exposures around the world. I mean, it’s not to say that maybe someday when Antarctica has finally lost its ice cap, that we will find all kinds of cool stuff there. Or when we find new early Triassic sites say in China or in parts of Africa, that there will be things in there that we can’t even imagine.

Shane Hanlon:              24:51                So there may be lots of Triassic creatures waiting to be discovered fossilized in places that we can’t access because they’re covered with ice or not on the surface of the earth. Right?

Devin Reese:                 25:02                Yeah. I hadn’t really thought about it that way. The paleontologists are finding a tiny sample of what got preserved, like the parts that are exposed, but still so many weird Triassic animals have been found.

Vicky Thompson:           25:16                You know, I wonder what happened to all those strange animals towards the end of the Triassic?

Hans Sues:                    25:21                It’s interesting that the other side of the extinction sandwich probably had the same kill mechanism that the beginning had, namely massive volcanic eruptions.

Hans Sues:                    25:34                We always think about extinctions in terms of extraterrestrial causes, ever since people discovered that basically cretaceous extinction, which wiped out all the dinosaurs except birds, was caused by an asteroid impact. So people think, “oh, maybe all of these big extinctions are caused by this”. And indeed a lot of researchers who are not paleontologists have been running around the world trying to find impact craters that can be dated in order to explain these other extinction events. But the reality is for the End-Permian and also the End-Triassic extinction, it’s massive volcanic activity.

Hans Sues:                    26:14                Now in the case of the End-Triassic, it’s very interesting because it does concern us here on the east coast, because basically when Pangaea, the super continent, started slowly breaking up, the first major break that developed is the area that is now the north Northern part of the Atlantic ocean.

Hans Sues:                    26:35                I mentioned this rift valley that formed between what’s now Eastern north America and Europe and north Africa on the other side. And what happened was that this rift expanded and suddenly immense quantities of basalt lavas came up over an area of about six million square kilometers. In fact, this was the largest volcanic activity like that, even bigger than the one that caused the End-Permian extinction and basically all the way from what is now Greenland all the way down to the Gulf of Mexico, down to Brazil, to west Africa, this was one giant zone of volcanic activity. And we have very good dates for those volcanic rocks and this all happened within about a million years.

Hans Sues:                    27:23                So imagine this global event, the climate went completely to hell because initially after a volcanic eruption like this, you have all the sulfuric dioxide going up into the atmosphere. It comes down again as little droplets of sulfuric acid, which cool down things because they reflect the sunlight just like volcanoes do today. And then after that, all the CO2 that has been spewed out, kicks in and so you go from an already warm world in the Triassic to something that’s just like really super hot. And of course, that really affected ecosystems both on land and in the sea in extreme measures.

Devin Reese:                 28:07                So to me that doesn’t sound like conditions under which really anything should survive. It sounds like a living hell.

Hans Sues:                    28:15                It certainly would have been.

Devin Reese:                 28:16                But obviously some things squeak through or we wouldn’t be having this discussion today. So what squeaked through and how?

Hans Sues:                    28:26                Yeah, if you want to have a modern analog of what was going on, there’s an area in Ethiopia called the Afar Triangle, which is a really desolate, boiling hot place, hardly with any life that would’ve been, what Eastern north America would’ve been looking like right then. But then the volcanism sort of started tapering off, there was still quite a bit of volcanic activity going into the Jurassic, but at the same time, you suddenly see a whole bunch of new animals showing up. The vegetation has changed, but new kinds of plants show up, so for instance, in the Triassic, you have all these ferns and conifers, and when you get into the early Jurassic here in Eastern north America, suddenly almost the entire vegetation’s made up of these very hardy conifers that have really needles with very thick skins or cuticles.

Devin Reese:                 29:22                Okay. So some conifers squeaked through, ones that were more fire adapted, and what are in terms of vertebrate animals, what made it through and why, the ones that made it through, how could they have survived these conditions?

Hans Sues:                    29:39                Well, of course, small animals can always get out of bad conditions like that by going underground, just like today, mammals and lizards, most small species are burrowing animals or usually borrows of other animals that do borrow some animals survive because they’re in lakes and rivers and I mean, obviously there was water around, otherwise there would’ve been known life at all. And so quite a few things can survive. The other thing of course is that the world is obviously not one uniform place. There would’ve been areas that would’ve been less affected and there could have been then used as reservoirs for animals and plants from which it then could spread out again into the other now decimated areas to repopulate. But the really interesting thing is that there’s this great competition between two major lineages of Archosaurians and reptiles, that’s the line that leads to crocodilians today, and the line that leads to dinosaurs, including birds.

Hans Sues:                    30:37                And interestingly, during the Triassic, we have the heyday of the crocodile, like Archosaurs, like these Rauisuchians, the Hylaeosaurs, the heavily armored things, the phytosaurs, but all of these disappear at the end of the Triassic, and they were really the dominant land predators before dinosaurs became the dominant land predators at the beginning of the Jurassic. Rauisuchians completely disappear, but dinosaurs which already showed up in the Triassic, go through the transition without any known losses at all. So dinosaurs fared well, and one of the big questions that we actually right now are examining is a group led by Paul Olson, that I’m part of, we have some ideas now why that may be the case, but of course, we now have to publish them and sort of get the input from the scientific community on this. But dinosaurs are a real success story.

Hans Sues:                    31:30                And it has been argued that either this was due to competition, that dinosaurs had somehow features that made them superior to crocodile line Archosaurs, or the other hypothesis, which I find a little bit more plausible, but it’s very difficult to sort of test scientifically, is the fact that the crocodile line Archosaurs largely disappear except the liens that ultimately lead to modern crocodilians. But that basically, because all of these competitors disappear, you have new ecological opportunities and dinosaurs just took advantage of them. So it wasn’t some kind of active competition, but rather dinosaurs took over by default.

Devin Reese:                 32:13                I can’t wait to see that new paper that you’re talking about. So, all right. So then if we’re going to teleport you to a particular geographic region for you to spend the end of the Triassic, where do you choose?

Hans Sues:                    32:28                I think I would go to what’s now Argentina or Brazil, because that’s far enough away from the worst of it.

Devin Reese:                 32:37                All right. So for the end of the podcast, at least of this recording, we’re going to teleport you, like you requested to Argentina.

Hans Sues:                    32:44                Actually, what I would most like to see would be one of those giant Rauisuchians, the top predators before the dinosaurs took over that role. And I mean, there must be, imagine something, this giant land crocodile-like thing with long legs, they had a very upright walk, same upright sort of narrow gait walk, enormous skulls with in some cases T-Rex size teeth. And that would’ve been a really cool sight.

Shane Hanlon:              33:25                I Googled Rauisuchians and also how to pronounce it. I want to be correct here. And the thing is wild and here’s the thing about seeing one, if you see one, they can also see you. And that is far too close for comfort for me.

Vicky Thompson:           33:42                Yeah. I would never want to be that close to it. Also, it walks like the description of it walking upright, but it’s almost too human in that way.

Shane Hanlon:              33:54                Yeah. There’s there’s the fear factor. And then the uncanny factor.

Vicky Thompson:           33:58                Uncanny, yes.

Shane Hanlon:              33:59                Something just doesn’t look right with this. Well with that wonderful image in everyone’s head, that’s all from Third Pod from the Sun.

Vicky Thompson:           34:07                Thanks so much to Devin for bringing us this story and to Hans for sharing his work with us.

Shane Hanlon:              34:12                This episode was produced by Devin with audio engineering from Colin Warren.

Vicky Thompson:           34:17                We’d love to hear your thoughts on this podcast, please rate and review us, and you can find new episodes on your favorite podcasting app or at thirdpodfromthesun.com.

Shane Hanlon:              34:26                Thanks all. And we’ll see you next week.

Shane Hanlon:              34:33                Cool. All right, one more.

Vicky Thompson:           34:34                Okay.

Shane Hanlon:              34:34                I’m just getting all in Vicky. Like we’re just,

Vicky Thompson:           34:37                I love it.

Shane Hanlon:              34:39                I’m getting this wonderful time with you.


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