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Always read the leafless Oh hey, it's your neighbor's Wi Fi network that shows up as New England clam Router Ali word and we are biting up just enough to chew about ancient animal anatomy, particularly little weird teeth. I know you never knew that you needed to know about this, and it's wild. It's fascinating, I promise you. It's like a little corner of the earth in time you'd never otherwise imagine unless you are this ologist or one of
their colleagues, paleontologists who study fossilized prehistoric tissue samples. I love this This ologist, an old friend I met on the internet on Twitter, ye old Twitter, and someone who was always on hand to help identify a bone, who popularized the hashtag guess the skull and loves the history
of bones. They were born in Morocco. They grew up in Egypt and moved to Canada as a preteen, then did undergrad in pre med at the University of Toronto before getting a master's in ecology and evolutionary biology there studying animal jawbones. Then they got their PhD at the Humboldt University of Berlin and as a postdoc at the University of Chicago. Has already published several papers, including the twenty twenty five Nature paper The Origin of Vertebrate Teeth
An Evolution of Sensory exoskeletons. That's like shaking up the fossil world. And in addition to being a professional paleontologist and an evolutionary biologist, they are also a celebrated science communicator who says that they love finding creative ways to make science accessible, weird, and wonderful for everyone, which this
episode does so much. So we're going to get into it in a minute, but first, thank you so much to patrons of the show who make it possible and they send in hilarious and thoughtful questions before we record. Thank you to everyone out there supporting the show by wearing our merch from ologismerch dot com. As a reminder, also, we have a shorter kid friendly episode suitable for all ages and classroom safe and those are called somologies Smologies.
They're available in their own feed wherever you get podcasts, you can subscribe. And thanks to everyone who leaves reviews of the show and to evidence that I do read them all. Thank you to recent reviewer Coco reads Books who said that ologies quote can make the most obscure, weird topic super interesting. Coco, you have no idea, We're about to do it again, Okay. Paleohstology it comes from the words for old tissues, and the histo in tissues
comes from an older Greek word that means web. And I was in Chicago a few months ago for our friend's wedding, and the afternoon before the rehearsal dinner, I romped off to the Field Museum to lurk behind the scenes with this ologist I had been admiring from the Internet for years. I saw drawers of bones, millions of years old skulls, microscopes, and the evidence that changed how
we think about what grows in our mouths. So prepare to drop your jaws as we discuss the origins of teeth, why yours hurt sometimes, how they got in your mouth, the long debated rumors of extinct species, how particle accelerators and paleontology worlds collide, what tools fossil pickers rely on, teeny tiny mysteries, busting age, old flame plan and why you should hug a chery before it kills you. Plus
why a catfish might become your overlord. With science communicator, researcher, paleontologist, tooth enthusiast and researcher of ancient tissues paleohistologists. Doctor Yara Tardi.
Fir Sing.
I'll have you as we could say your first and last name in the pronounce you use.
So I'miara Haredi, doctor Haredi, doctor Jara Haredi. She her pronouns.
When did you defend your phg I.
Was officially awarded to me in January twenty twenty two. Yeah.
I followed you on Twitter for yearss. I know, in the beforetimes, in the before times, the rocking, it was Twitter. That's where all the scientists gathered.
It was such a beautiful time.
It was a beautiful time. I got to know your work, and I always loved that whenever someone found a like a raccoon skull under a shed, they would tag you like.
Why is this? I did become like a go to bone and tooth person, which was my goal in the first place. And honestly that it's so sad because I used to suggest like social media as a go to thing all the time for even for like young people, like young people who are trying to get into science, because it was such a good resource. You know, I
got jobs off of it. I got talking head gigs, I got collaborations, like actual science collaborations where someone's like, well wait, I have the machine that can do this.
Yeah.
I got friends, I got you know, all that kind of stuff. And it was really really beautiful place. Hopefully science will come together again somewhere else.
Guy, So I am excited to catch up with you because I wanted to have you on for so long. Now, okay, the ology itself. I saw that you have a paper histological skeleto chronology that a possibility, paleo dentology. What are we thinking? What would you say your ology is?
I mean when people ask me, like what my main method is, it's paleohistology. So I feel like that would be a really good one. And paleo hostology is just the study of ancient tissues. So histology is just literally the study of tissues, and then paleohstology you just make that ancient old old, yeah, old old.
We're talking tissues, but we're also talking teeth. Is a tooth a.
Tissue, so what makes up a tooth? Are the different tissues we'll be talking about, So like dentine enamel. Those are like words that people have heard from you know, your tooth paste commercials. Yeah, so those will be the tissues, but the structure as a whole is the tooth.
And take me back, when did you start getting interested in paleontology? Oh?
Girl, this is this is like I feel like it's such an odd story because so many people, especially in paleo, they were dino kids and they knew they you know, my husband's that way where he's like, I just knew that this is at least a direction I wanted to go, not paleo particularly, but like art for example, Paleo tends to be like that where a lot of people have been into it since forever. But I took like a
couple of wrong turns to even get here. So I grew up in the Middle East, and in the Middle East you don't really have like a dinosaur phase as a kid. It wasn't marketed that way. You know, I'm nineteen ninety four, so goodyear. But you know, Jurassic Park was just becoming like big, and so it just wasn't as big in the Middle East, and it wasn't a thing, and I didn't really understand that that could be a career. And so then we immigrated to Canada and I started
going to university and really being interested in science. And you know, I am Egyptian, so in our culture you can be a few things. You can be a doctor, you can be a pharmacist, you can be an engineer, or you can be a disappointment. So what I decided to go into a science and try to at least go into being a doctor. So I studying for med school, and man, I just wasn't enjoying it. And the parts that I enjoyed were the anatomy, the physiology, how things worked.
As I was studying for med school, I volunteered in a paleo lab and I fell in love with paleontology. And yeah, couple of right turns turned left, or a couple left turns turned right, and I got into paleo. They offered me a master's and I continued from there.
What was it about it? Was it just the age, like the unfathomable age? Was it the structures?
That's a really good question, and I can actually mark the point where it happened. They had me picking fossils, and picking fossils is when you just sit on a microscope and you're like picking little microscopic like little bones from salamanders or teeth, and that was fun, and I
think the shape of fossils is interesting. And I was just kind of mind blown that these were from the Permian, so they were two hundred and eighty plus million years old, which breaks your brain, yeah, if you are not used to those numbers and who is Yeah. But then there was a PhD student in the lab at the time and he taught me this method calledology and the study
of tissues. And I didn't understand what that meant at the time, because what do you mean tissues survived in these two hundred and eighty million plus year old fossils, And so we cut them up and you can see under the microscope the bone tissue. You can start asking different questions like how old does this animal, how did it grow? How fast does it grow? What are the blood vessels? Like, same thing with teeth, Does it replace
its teeth? How does it grow its teeth? All that was still preserved, and at that point it went from like mind blown to like shattered, like gone, because that was crazy. You can see cell spaces, you can see lines where like you know this animal had a hard winter. All that was recorded in the fossils, and at that point I was like, oh wait, this might be a
real signal, actual thing. Well before that, everyone's just photographing externally like these fossils and it's not that that isn't science, of course it is, but it just wasn't as it didn't tickle that little part of my brain of like, we can go deeper, we can see how this animal ticked, What did its blood vessels do, what did it cells do? Yeah?
I feel like if you were not a fossil person, not a palaeo person, you think the only things that maybe survived were the bones, and then you read an article where you're like, we know that there were feathers in here. Okay, we know there were scales, but I either imagined hard bones that survived and everything else rotted out or scales something something still hard, something's still hard, Yeah, something with a structure to it.
And that's fair because that's the vast majority of fossils. That's like ninety nine point nine percent of fossils are actually teeth because enamel is the hardest vertebrate tissue and so it survives really well, it's already very crystallized, so like how much more crystallized can the Earth make?
You?
Yeah, so they.
Survive really really well, a bone being secondary to that. But there are exceptional preservation moments in Earth where the right bacteria didn't get to it or the right bacteria did get to it, and they preserve feathers, they preferserve skin. We now have ichtheosaur lubber people like, have you know, actually done isotopic measurements and know that it's fat that was preserved in a really interesting chemical way.
And it is rock. But it takes the impression of all those tissues not.
Always oh yeah, okay, yeah yeah yeah, so fair right, that's kind of the old thinking of like, well it's just an impression, like the scales for example, like how do you know, like dinosaur mummies and stuff.
Sometimes they are impressions. Sometimes the soft tissue left an impression and then disappear. Sometimes the tissue itself gets mineralized. So for example, let's think of your skin. There's multiple layers in your skin, and some parts of them basically get replaced one to one, or they get cross linked or get changed in some chemical way that makes them stable, so they actually preserve as that tissue that has been infused with new chemicals that are stable.
I didn't realize that soft tissues were even something that you could look at. Now, between the soft tissue and the teeth, teeth obviously evolved over time. When did things start getting teeth?
So that is basically the question of my life. When did things start getting teeth? Or if I can like extrapolate that even more, it's like when did things start getting mineralized tissues? Okay, so we have this process called biomineralization where we or organisms as a whole, will basically take minerals from the environment and make a skeleton out of them. And we're not the first to do that. You know, Sponges have skeletons, they have glass skeletons. Shelled
organisms like mollusks they have skeletons too. Those shells count calcium carbonate skeletons. Arthropods have exoskeletons. So just taking stuff from the environment and making your own skeleton, we do that too, and so we make bone, we make teeth. Our skeletons are made of calcium phosphate. But what's interesting, of course, is that at least mineralized specimens fossilize really well. And so we can go back in time and be like, Okay, what's the first animal to have tooth tissues on it?
What are the first animal to have bone tissues on it? And as far as we know, we kind of trace it all the way back, deep, deep, deep in time into like the middle or division, So about four hundred and fifty five million years ago. Yeah, hard to can sceptualize, right, So dinosaurs one extinct twin six sixty five. Yeah, yeah, right, So and then these bones existed for a very long time. Tooth tissues have existed for a very long time. And I say tooth tissues because they weren't exactly teeth.
Were they ever made of cartilage and get harder or they were always mineralized. Did animals ever have like kind of gummy like bit like kind.
Of like teeth, I love? Did they just gum things to death in the ocean? Yeah? Probably, But also more likely is that they were just suction feeding. There was some kind of filter feeding that happened early on. So the very first tooth like structures to appear in the fossil record don't appear in the mouth. They appear on the outside of fish. No appear on the outside on these like scales and the normal bone, which is partially nightmarish until you see how ridiculous these fish look like
because they're nonsense looking. They look like you don't get like a handheld vacuum that you're gonna like clean your car with, or they look like that but stick googly eyes on the end. No, their mouth is always open because they don't have jaws yet. So these little tooth like things that are on the outside of these fish, we call them adontod's, So that's a word I'm going to be using often. So adontoad's are little chunks that basically look like a tooth, but they're on the outside
of the mouth. They're made of enamel and denteene and they have a pulp cavity, but they cover the outside of fish rather than being the inside of the mouth.
It sounds like a terratoma, you know, yeah, totally a blob item with tease sticking out everywhere. But what did they use them for on the outside boom exactly?
We don't like, So we don't know, or we didn't know. We had a couple of hypotheses. Why would you have these things on the outside of your body. The very first answer was always like protection, Like, oh, you're making your hardest to show on the outside of the body. You're to make armor. You know, a lot of modern fish do that, Things like gar have really hardened scales that cover their entire bodies. Makes it harder for things
to bite you. Yeah, it makes it harder for parasite to get attached, et cetera, et cetera.
Please please see our grology episode about long cute, ancient patient poopable nightmare fish with the iconic biologist and punster doctor Solomon David, as well as our Terrotology episode about the history and culture of monsters in fiction. Because a terotoma is a blob that can grow in your body, but with fully formed teeth and clots of hair. And if you listen to the end of the episode, I'll tell you my own personal secret about tarotomas. But yes, millions of years before actual teeth.
And of course the image of like teeth outside the mouth is so grotesque. Yeah, but if you think about like modern sharks, modern sharks have teeth outside the mouth, or they have these odontos they're covered in them. So if you put sharks one way, it's smooth, but if you put them the other way, it's super rough. That sandpaper feeling you get from sharks because they have little, tiny teeth all in their skin.
Those are adontos. Yeah, exactly, hovered in tiny teeth. Mm hmm, yeah, I love that. The big teeth in a shark are what freak people out, but little do they know they have an army of tiny teeth also backing them up.
Yep.
So the first ones though we're outside the body, when did they start merging into the hole?
Into the hole? Should we go back to the what are they four on the outside. So there's a couple of floating hypotheses. There's one that's like, okay, they're for protection because they're hard on their own and they're on the outside, and at that time period middle order of vision, there's like big scary things in the ocean, big cephalopo that's so big, squid not alloid looking things that would
eat our little fishy ancestors. There's big sea scorpions that are bigger than you or I, that are up to like six feet or more. Again, things that would eat our little fishy ancestors, So it makes sense that the first hypothesis was protection. Another one that's based more on sharks is that maybe it helps them with low commotion. So when I said these fish are really weird looking, they don't have fins yet. So the first ones didn't
have pectoral fins. They just had a tail. It's like a tube, like I said, it's an handheld vacuum with eyes on the end and an open mouth. So how do they move around in these like turbulent seas? How do you make your low emotion more efficient? Sharks they use the little spikes in their skin, these little teeth on the outside there are down to toads to help basically with hydrodynamics, the way that the water flows over their body is more efficient because of the little bumps
all over them. So maybe the early fish did that too, So that's one other theory. And then the last theories that maybe it has something to do with sensation, that maybe because our modern teeth are soundsitive, maybe the outside ones are as well.
How big were these outside ones? Were they teeny or were they like I.
Should just show you. They're in the cabinets behind us.
Yeah, grab one yeah, yeah, give me one second, okay. I just love that. You're like, well, we've got something that's millions and millions of years old over here, like how I would pull a coffee milk out of a cabinet. This is the first time I've ever heard the word odonto also, which is exciting. I didn't know that there was even a generalized name for them. This hall of cabinets is so bonkers.
So I have a part of a headshield from adults fish. And what you can see here all these little bumps, each one of them's a little tooth.
No, it looks adant to It looks kind of like a tiny cottage cheese ceiling, you know.
Yeah, yeah, the popcorniness of it.
The textures, they're like little tiny beads almost. And now you clarified that you have gotten flack here and there for calling it a tooth, because a tooth is in a jaw. But we're talking broadly to communicate what it's an analogous structure, right.
Or homologous right, okay, because they have the same origin. So the reason that we know that these danto's on the outside of the mouth are even related to teeth, it's because they're made of the same thing. They're made of enamel, they're made of dente, and they have pulp cavities. They have the same blood supply, So they act very similar to our own teeth in the mouth, except that they don't replace the same way, and they don't have a job in that they.
Don't And then they started coming merging. They started saying, let's get in the hole.
So how did we get teeth in the mouth, or how did you go from Adonto's things that are bumpy outside the head to things that I can bite other fish with. So that happened along, we assume sometime probably the Devonian.
So the Devonian was a cute little sixty million year era from about four hundred and twenty million years ago to three hundred and sixty or so million years ago, and it was a party. It involved plants growing on land, the formation of leaves and seeds, critters slithering out of the water into their terrestrial destinies. We had shelled bugs, We had fishes with jaws. In fact, it was called
the Age of fishes. There were even now extinct things called placoderms, meaning flat plate fish that looked like they were wearing bulletproof vests and helmets. Four hundred million years ago, primitive sharks were like, hey, about a million years before trees existed, Sharks older than trees also be nice to sharks. Trees killed seventy one people in the US in twenty twenty three, but unprovoked sharks killed ten globally. Only two
of those were in the US. Sharks are the eldest daughter of our planet.
And so what we have is a couple of fossils that are covered in these little bumps all the way across their face and right at the margin of the jaw, which had now evolved. You have sharper and pointier down toads, and they kind of grade into the mouth, and then you have actual pointy things in the mouth. It's not ostensibly teeth. We see those probably, So that's one way
that we think it happened. The other way that we think it could have happened is just whatever genetics that make up ADNT toad's they got re expressed inside the mouth.
Oh okay, right, So it doesn't have to be.
A gradual like actual movement of the structure into the mouth, but it can be a re expression. Just hey, let me take this toolbox that I use up here, and I'm gonna express it in the mouth.
Instead, kind of like when you get a weird hair that pops up somewhere else, you go, what are you doing?
Yeah, except I don't recommend tweezing auster your tooth. Don't do it.
Don't do it. Okay. What's the difference between a tusk and a tooth? One is ivory? What's ivory?
Ivory is just denting.
Ivory is just denty. Does that mean there's no enamel or pulp?
So, tusks are just teeth, but they're fancy teeth in that they are usually non replacing, they're usually continuously growing. So elephants are the famous tusks. When they're babies, they have a little antibity enamel cap on the end of their tooth, and then as it keeps growing, that usually gets worn away because they just like rub them on trees, they dig with them, they fight, and then it ends up all being denteen. Yeah, got it? Okay.
I wonder why they don't keep the enamel since the enamel's so hard.
Well, I think it's just gets worn away after all. While also there's a bunch of studies that are really interesting that show that elephants use their tusks as like sensory things, So they hit them on the ground and they like feel vibrations with them. Yeah, so there's some kind of feedback that they're not just like whacking around big sticks like. There is some feedback. It's a living tissue.
Right underneath that is the yellowish dentine, which is softer than the outside enamel but still hard tissue, and it's protecting that little lump of inner pulp in the tooth.
And dentine is made up of collagen proteins and according to a chapter in the journal Engineered Regeneration Banger have a book, there are fine tubes arranged in dentine known as dentine tubules, and when dentine is exposed, it can transfer cold, hot, sour and sweet stimulation from outside to the pulp nerve and cause pain and darlings, we owe you an odentology teeth episode. We also owe you an elephant episode or working on it. Our packadematologist of choice
has been in the field for like two years. We're waiting for her to become available. Please don't yell at me, sweet little brats. And this is one thing in a recent paper of yours about sensitive teeth, like blame your fish ancestors, yep, which I got a ground replaced and I can't drink cold wine that side, and it's been like two months, and I'm just angry about it, and I'm dehydrated and oh no, it's just I guess the time mentioned. But I do blame my fish ancestors. I'm
pissed at them. So a sensory organ on the outside also helps them figure out like how cold the water is what?
This is such a good question, but basically we don't know. We don't know what they're sensing. Because not only are we sensing cold, we can sense sweetness. We can sense pressure with our teeth. Some people have sweet sensitivity, so they just eat like a candy and they get sensitivity from him. I mean, you know you felt like if you press really hard on your teeth, you can feel them.
I know you just pressed on your teeth, I know it. Yeah, So our.
Teeth can sense multiple things. The reason we sense cold is later Basically the signal gets sent out, and how does it get decoded? Later? Your brain says this signal means cold, so that happens down the line that could technically be almost anything. So I don't know if these early fish had this tissue basically and then downstream they had it sense for like, hey, it's warm water or cold water, or a change in tides, or something's trying to bite me, or the sediment flow change or any
of that. We don't know exactly what they're sensing, but we know that some kind of signal was getting passed.
And then tell me a little bit about this paper.
This paper has been the nightmare of the past three years.
Okay, checks out.
Yeah, So it's an interesting story because it's a really winding pathway, and I think it shows how science is not very linear, and sometimes when we set out to research one thing or look for one thing, we get a much more complicated story, which tends to be a lot more interesting. So I basically had pitched to come to Chicago to do my work at University of Chicago. I pitched, hey, I want to look at the very first thing in the fossil record that might have a Danto's,
that might have bone. Let's figure out where our skeletons came from by understanding these early tissues. I want to cut it up. I want to scan it. We have really good ways to scan things. Now, let's like throw everything at this fossil. And the fossil I was really interested in was this animal from the latest Cambrian.
And again, this was three hundred to four hundred million years ago. This was hundreds of millions of years before Pangaea existed and then broke apart. So we're going way way back. And doctor Heridi is like casually in possession of teeth of an age that are beyond my capacity
to fathom. She published a paper in May of twenty twenty five in the venerated journal Nature titled the Origin of Vertebrate Teeth and Evolution of Sensory Exoskeletons, and it reads, the origin of vertebrate teeth has been a long standing problem in paleontology. Although teeth evolved from structures in the dermal exoskeleton of Jallais vertebrates known as odontod's, their origin
and function remains obscure. And this paper is groundbreaking And that's not a fossil pun but it's already racking up citations despite being like just a few months old. So we'll get into why later in the episode when we know what more words mean, and also it's a juicy story and had some fascinating reactions.
Now, if you remember earlier, I said, the best thing is that we know the earliest vertebrates are from the Middle Order vision. The just Cambrian is just before the order vision. But the problem with these fossils is that they're super fragmentary. And when I say super fragmentary, I'm saying like tiny, like fits on an end of a toothpick. Tiny.
Oh dear, yeah, oh dear.
Is right because when you tell someone I'm a paleontologist and then you show them the fossils you work on, I make a lot of seven year olds very disappointed and fragmentary.
That's the whole tooth or that is just it burst into shards.
I should show you me.
Yeah, yeah, that.
I got how they're actually the rock.
You know what they look like. They look like nerds. It's like the smallest nerds and they're in a vial you're pouring them out. Those are teeth. Those look like gravel, I know, right, Those look like decomposed granite in a fancy garden.
Do you see the little white bumps. Yes, So this is part of dermal bone on these ancient fish. So I'm basically holding like, what is it, you say, fragments of like cereal. They're so tiny, they are.
Like grape nuts tiny, and we.
Get really good data from them. Oddly enough, they scan beautifully, they section beautifully under a microscope. They're just gorgeous, and the enamel is intact. Every one of those little bumps is a little dantoed, every single one. So the adanto's adhere to the dermal bone and that's how they make their armor. Yeah, yeah, And so they're covered in these ones. They're really tiny. They're even tinier than the other piece
that I showed you earlier. And so this is the earliest representation of what some of these fragmentary early early mineralizing vertebrates look like.
They're teeny tiny.
So when someone tells you the fossil record is a problem, this is it.
I mean, you could overlook that so easily. And here you have a rock and you've circled some things and there are absolutely pin prick, little white lightish structures and you've got to go in there. Do you use, ironically a dental.
Tool, Yes, yes, yeah. We use dental tools all the time and dental putty to like make molds and stuff. Oh yeah, I'm friends with a lot of dentists.
I bet, I hope you have a good dentist. I can't believe how TEENI is.
So I just opened another vial and poured out another one, just scrap. But this one's supposedly from a different species, And so you can kind of tell because the shape of the odontodes is different. They're more elongate. They kind of look like little rice grains, except smaller than rice grains.
Yeah, they're like wavy almost.
Yeah.
So these grains of rice, these little pebbles, they are the proto teeth that covered marine animals four hundred and seventy five million years ago in what is now North America, and the ones we're looking at the vial of wavy rice grains that doctor Herrity painstakingly picked out of a rock. So we sat down at the table with this array of ancient specimens around us, like top us, they're all.
Over North America.
And how big was this animal?
It's a good question. We don't get many articulated specimens, so specimens that are still together and in life form, and so it's really hard to estimate. There is one partially articulated head which is only a couple of centimeters wide, but then there's another one that's like quite a bit bigger. So we don't know if what we're catching is a baby in an adult. We're really unsure. It's very hard to estimate what these earliest earliest ones looked like.
How many people in the world do.
This paleo hostology as a whole or looking for this, Probably a handful, probably less than ten of us.
Yeah, you guys don't know WhatsApp thread.
I don't think. So we kind of meet regularly in conferences and stuff, and then everyone kind of approaches it a little bit differently. So I'm probably one of the only ones that does the histology. A few others do, but some people look at it from morphology, so the shapes. Some people look at a taxonomy, they look at the actual like individual species. But I'm interested in the tissue. Why dentin, why enamel, why bone? And I'm interested in
that because before these guys, there was squishy boys. There's all kinds of squishy early vertebrates, and so I'm really interested in the jump from gouy things that were our vertebraty ancestors chordates, et cetera, to the jump of like fully armored fish, because in the fossil record that looks like it just happens. There's no transition between fully naked goofy thing to mega armored fish. We don't have anything in the middle. We don't have a lightly armored fish in between.
Is it unnerving to know that that missing link is somewhere in a rock y'all haven't found yet.
I think that's a hopeful thing because I'm unexcited. I mean, that's the direction I want my research to go. That's what we're hoping to find. Is still you know, when I talk to kids nowadays, they're like, oh, everything's been discovered, or you know a lot of people think that about science, Oh everything's already been found out, but there's still so much mystery, and this is one of them. So there's a lot of space for young scientists to come in
and expand, especially with your technology. There's a lot of ways to ask or re ask old questions.
Are you out in the field wearing khaki garments and like a hat in most of the summer, what does your field work look like?
So I was just out in Colorado. We were looking at this one road cut. So there's this one area they're about to dynamite because they're making this road really wide, and that area has this formation called the Harding sandstone, which is something that we are interested in because that's where we find these little guys from the middle or division. So they called me up and they're like, hey, are you interested in working on this before we blow it up? Absolutely? Yes, please.
So we've been out there digging, yeah, the whole the whole thing. And we dug a lot in the hillside, found a lot of these fragments, a lot of scales. We were very lucky, but we're still looking for a more complete guy because that's really what we want. I want to see what a face of these weirdos looks like, Yeah, have a tail? Is it? You know, all that kind of stuff. So we weren't able to hit that just yet, but we'll go back soon.
I remember talking to Michael Habib and asking about how much it costs for a dino dig and he's like, guess And I was like two million, three million. He was like ten thousand dollars. Yeah, and I was like less than a camri, less than a used camri to dig up dinosaurs. Like, is it tough to get an inn when you know they're going to dynamite something and you're like, oh, there's so much bun stuff in there.
Do you have to choose? Like I'm gonna put this on hold and I'm going to go to the place where you're about to dynamite and I'll get to you later in the protected lands.
Totally? Totally, I mean, but that's life, right. You have to kind of move things around, reprioritize. So when we found out that this area was getting dynamited, we want to check it out. Moved a bunch of things aside and went checked it out. But like have you said,
it's so much cheaper than people think. And that's again why it's even crazier that it's so hard to get science funding, because I mean, my last field work was maybe only two three grand to get a few people out there for a whole week and dig it up and you know, and really get a good survey and do a lot of science, a lot of science. But it's just hard. It's sometimes hard to scrap that together.
Yeah, Bond cursed to me, considering that that's like one dinner. That's like one dinner in washing take, it's just some hopnobbing over champagne somewhere with a lobbyist. I don't know.
And now I think in many ways scientists are realizing that we need donors, We need people who are into it. Once you get the specimens out of the ground, they need to be prepared. And it's the preparation that can be really expensive because you're hiring a highly skilled person and paying them fairly, hope, and so that can be a lot of hours of manual, skilled labor. And people have funded that. People have found like waste to fund that.
They did that for Sue, Like, how do you fund the preparation of this giant yex It's a little bit easier to sell a t Rex than it is to sell a jallous floppy fish covered in tea. All my children are not loved.
All your gummy boys and your.
Floopy Yeah yeah, findless things?
Can I? I know we have so much more to cover, but can I cover it with patroon questions?
Absolutely?
Okay, let's see what they've asked, but first let's donate to a cause. Of yours choosing, and this week she selected the Semere Project, which assists families who want to return home to Gaza by cleaning the streets of rubble, cleaning debris filled structures, renting and fueling heavy machinery, and bringing large crews to tend to destroyed neighborhoods and working
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Hey Mark, how are you?
I'm not great a sore throat. I think I'm coming down with cold.
Oh no, you should try a Vogel sore throat spray. It's a natural remedy with echination and sage, I can treat symptoms of coals and flus, including sore throats.
Perfect. I'd give that a triso.
We leave sore throats symptoms with a Vogel a Quena four sore throat spray made from echinaesia and sage herbs and designed to reach irritated parts of the throat, available from health stores and pharmacies nationwide.
Always read the leaflet. Okay. Thanks also to patrons of the show who submit questions before we record via patreon dot com slash ologies. It is hard to select which of your strong toothy contenders to start with, but patrons Peter and Gregorius of Tomsk had a whale of one, as did mouse Paxton Spicy Native. Both wanted to know, in Spicy Native's words, bailing when it evolved is whale bailing mouse asks considered teeth.
Oh, it's a very good question.
What is it? I thought it was keratonized, right, you're right, okay, yeah, so not a teeth, not a not an odon. But you got it, odonto and you got this. Why can't they do.
It because you're not believing in yourself.
No, toads, it's fine. I knew at this word.
We'll get it. We'll get it, guys. No, you're absolutely right ten points rally okay, that they're totally chrotonized, and so if they're keratenized, they don't have dentine, they don't have an animal, and so they're not I did it.
I did it.
Good.
It's so proud of you. Yeah. Okay, So great question from your listeners, Bayleen. Is not teeth. It is a completely different tissue. And where did it come from? That's such a good question. So that's a whole section of study because we have fossils that look like they might have both. Oh yeah, so bailen whales came from toothy ancestors, they came from whales that have teeth, and so at some point they started losing one and gaining the other.
And that is quite like a controversial topic because I think there's like one team that's like, no, they lost teeth first and then gain baileen, and then another team says that there's an overlap there. But yeah, so it just depends on how you're interpreting these like really middle fossils. Or do you think all that extra vascularity, all that extra blood supply around the lip of this certain fossils that because of baileen or is that just because maybe it had fleshy lips.
I don't know.
So, yeah, that's a whole area. People don't really know exactly how they were Baileyan evolved, but I think people are getting closer. There's a lot of really cool new fossils in that time period.
Could baileen because it's carotenized and be sort of like hair that's like just hanging out in the mouth.
I mean, so keratin is incredibly diverse tissue because our skin has keraten, our hair has keraten, our nails, so it can just be expressed anywhere. Really, I'm not a whaleologist, but I think they probably just re expressed that there. I don't know what an intermediate would look like. Maybe I had like weird mustaches. I don't know, No, like a little wororus. That's a really good question.
We still haven't done a patology episode about whales, but we have done one on functional morphology that discusses what happens when a whale shows up on a beach dead and you have to go over the speed limit with a saw and axes in the backseat to get there before it explodes, but you get stopped by the cops. Mayan Marlowe Planet Sylrraine, Empress of Smallwood Teenas want to know Ryan usked? Are bird beaks teeth?
Ooh, bird beaks are not teeth. That's another keraten structure. But birds did have teeth at some point?
Do they not have teeth?
Now? No birds have teeth?
Now?
Oh, okay, what happened to them?
Very good question? Don't know?
Okay, how are they doing stuff?
They don't chew? Birds?
Don't chew at all.
No, Nope. Birds kind of like do a grab and swallow because I got the crop. They got a crop. They also have like sometimes little keraten horns on their tongue that help them push things back into their gullet. Yeah, their crop has like all these sole stones sometimes and grit and stuff that helps them chew. But they're kind of like whole meal eaters really. Yeah, they don't really chew. They'll tear things apart, you don't feed their babies and stuff,
but they won't chew. There is one hypothesis that basically, as teeth were lost in birdy ancestors, that's when the beak started to like fully envelop because it's kind of hard to imagine how beak and teeth coexist, like does the tooth keep growing through the beak, How those two tissues merge. I'm not saying it can't happen, but we just as so far as we know, things that have true beaks in the fossil record do not tend to have teeth, at least in the on the bird side.
So birds are dinosaurs. So on the direction of evolving to birds, they lost a lot of their teeth and did full ramphathica, which is the fancy word for beak.
So when you get attacked by a goose or killed by like a castawery castle casseri casswery, Yeah, they're gumming you with keratin sort of.
So I mean a goose is gonna like you can take a goose, Guys, most of you can take a goose. Don't. Don't upset the geese, but you can take a goose. You'll see like little bumps on the goose's beak and that's just keratin, like sticking down. They're not true teeth. And a cassewerre is not gonna kill you with this beak is gonna kill you with its foot again, another keratin structure. Don't mess with castwaorris. You can take a goose, but you can't take a castle.
No, don't do No, don't do it. That's one of my biggest fears. Yeah, just getting in it, accidentally getting in a situation where we're one on one and knowing I'm cooked, because I just know I would give up instantly. I just be like a grizzly. I'm like, maybe I could boop in the nose, but I can't boop that thing in the beak.
Or you're nuts, you're not.
I don't know.
I would take a cassewri over grizzly.
This is a good question.
It's a great question.
I'm gonna take a poll.
Would you guys take a castware or would you take a grizzly. I don't know. That's a great question.
I gotta figure out too. If castowarries can fly. I don't think they can at all.
Can't.
Yeah, okay, not even of a tree. Okay, grizzy can still Okay.
Also, castomories are such good dads. The dads do most of the caretaking. They're so sweet. Okay, Cuties hang out with the castwarris. Yeah, no, not the grizzlies.
I went down a detour looking for a castwerry expert, because, according to my friend Wikipedia, cassawerries are wary of humans, but if provoked, they are capable of inflicting serious, even fatal injuries. They are known to attack both dogs and people, and the cassawery has often been labeled the world's most dangerous bird, although in terms of recorded statistics, it says it pales in comparison to the common ostrich, which kills two to three humans per year in South Africa. Still
trees and gravity, they're a more vicious team. They will snaw and half not even blank on that note. Okay, Lars Watts, Howdie Crab Joshua YYZ want to know about bone density? Do you think from a histological perspective, do you think that hormones were affecting these structures? Like these odontodes said it louder, you killed them? I did know caffeine today? And I also why don't we do coffee first? I don't know. I don't know, and I will also
I'll plead also that I'm on Pacific time. But hormones affecting bone density, tooth density.
Bone density absolutely so definitely our hormones affect how most of our skeleton grows, but particularly our bones. This is why women are very susceptible in menopause to losing bone density. We start to loose some of our estrogen and that helps us maintain bone density. Basically tells our bone cells, these things called osteocytes, to be more sensitive in certain ways so that they can help other cells communicate. So a little bit of bone bio one oh one. But
basically within our bones. There's really just the three cell types. There's the osteoclasts, the bone destroyers, osteoblasts the bone builders, and then osteocytes the ones that live and maintain inside the bone.
So we have an osteology episode all about bones and donating yourself to a body farm. But I'm gonna blame two hours of jet lag for my memory soggy spots, and I love a refresher.
But when we lose hormones, or certain types of hormones, it messes with the way that they communicate, and so all of a sudden you have more osteoclast activity, so removing too much bone and not enough building of bone. What happens when that we get osteoporosis. Yeah, and so totally, hormones play a huge role in how we maintain our skeleton,
particularly bone density. This is also a problem when it comes to space travel, because we lose bone density if we're not actually working out or getting gravity acting upon our skeletons. So that's how the twin experiment where they sent one, yeah, one astronaut space and left his twin on Earth came back and I think he had lost some crazy amount of bone den City and it takes them a certain number of months to gain that back.
Just to side note, we talked about these twins and the one on Earth being like you can take them of blood and poop for science, but I'd draw the line at eating rehydrated steak, and that was in the Astrobramatology episode about space food. But for more on this parent trap of space data, you can see the NASA Twins Study, a multi dimensional analysis of a year long human space flight. For the record, I have never looked at this paper. I've never seen so many co authors
on one study. I squinted counting eighty four of them, and I might be one or two off because I counted so long that I got bored and I started thinking about hockey players kissing. But yeah, this NASA Twin study about twin brothers, Scott and Mark Kelly, both astronauts. Mark Kelly, yes, an astronaut and an Arizona State senator,
husband to Gabby Giffords. It involved physiological, telemetric, transcriptomic, epigenetic, protemic, metabolic, immune, microbiomic, cardiovascular, vision related and cognitive data that were collected over twenty five months, and it found changes in telomere length and epigenetics, changes in gut biome, body weight, carotid artery dimensions, retinal thickness, inflammation, cytokines, cognitive performance, and bone density which dropped several percentage points.
But yes, many things can break down that scaffolding in your body. And then is the same thing true for pressure with teeth? Does enamel wear down or do your teeth say, hey, we've got a lot of pressure, I better build this up.
So unfortunately, our teeth don't react the same way because they don't have osteocydes, they don't usually have cells inside that will adapt to the change in real time. There's small adaptations, especially with our teeth human teeth that we
have things like secondary denteene. We have a slight remineralization of our enamel, so you know, if you have really weak enamel, there are ways to make it stronger, floride being one of them, and then dentee and if there's damage, you'll have secondary denteene starts to deposit and like kind
of block the whole from forming. That's kind of how our teeth try to react to cavities because you really don't want to hold right to your nerves which are in your pulp cavity, which is why your teeth hurt.
Yeah, yeah, oof, we need a tooth episode, I know, but your pod mother recently found out that his tooth clenching at night has worn down his enamel and contributed to cavities. And he's pissed and now he has to wear a nightguard. But he can't really talk with it yet because you just got it. So in bed, he'll turn out the light to go to sleep, but then he thinks of something else to tell me, and I can't understand a word he says. But it's spitty and
it's charming. Mouth guarters, you're not alone, you're doing so. Patrons asking about historical tooth decay Katie Elmer, mm A t rot Weisswaffle hand the Bee, Kim Greneer era Victor Empress of Smallwood, Mariah Waltzer, and Dellie Dames. This is a good question. Also, everyone, you gotta brush your kiddies and doggies teeth. We love their disgusting devil breath, but you got to get in there, rub them with a little veterinary toothpaste and a brush or a rag. Tell
them they're precious and perfect. Babies. If you have a pet shark, you might have to brush them less because they are sharp, and also because their teeth are like on a subscription model, they just keep showing up. They lose on average a tooth a week. Patron's envious of this adapt patient had questions, including regular who asked, why do we only get two sets of teeth in our life while other animals get infinite teeth? Actually? Is that true?
Or flimflam? They ask, as well as Lori Fulford Win, Rebecca Smith, you can walk her, Naomi Jane Alyssa McElroy, Kats, Alexandra Rambo, Sheila Mariita Honeypye, Tom Bowdery, Catherine b First time question askers Arianna Rose, Planet Si Lorrain and Lisa Gorman, who asked, it seems like a lot of us mammals in general could benefit from the ability to grow some spears, okay, losing teeth lunar crumpet and others. Why do some animals
lose teeth and replace them like sharks. I see people in Florida, their beaches are lousy with these shark teeth, and I'm like, where are you getting these?
Like?
Who are these sharks? Just shedding them, you know, like cigarette butts. Why do some animals pop them out? Also those X rays of children that have a whole row of teeth in the way, those are real, Oh jeez, oh yeah, oh jeez. So how come why do some of us retain our teeth for as long as we can and others are just like popping them off?
So great question. Tooth replacement or constant truth replacement is the original state. Once tooth replacement evolved, almost everything kept replacing its teeth. Oh so, salamanders replace their teeth, reptiles replace their teeth, everything, everything until mammals. And there's a couple of exceptions of course, with full tooth loss, Like birds don't replace their teeth because they don't have any.
So mammals basically reduce that to a really extreme extent where we only have the two sets, the baby teeth and our adult teeth. Right, So the baby teeth are what you're seeing in those baby x rays.
Yeah, horrifying, terrifying.
But they're just like in weight, right, So they're like a full adult tooth made right above the or below the current baby tooth, and it's just like lying in wait and like waiting to erupt.
Many patrons had teeth on the brain, including mycologist Janet R. Damn Camacho, Emily Staffer, Talia Dunyak Crh, and Nancy K. Clark. And yeah, by the age of three, most tiny people have all twenty of their baby teeth, with thirty two hanging out in a jaw condominium upstairs. And if you've I've seen X rays of baby heads or medical specimens,
rest in peace. It looks like a lotus pod. And if you don't have natal osteophobia, then your tripophobia of holes will definitely kick in round nubbins housed in holes. As your Internet father, dad word, I do not recommend googling baby skulls in general, but definitely not in a packed cafe on a Sunday afternoon full of Macha drinkers. I wanted to keep looking. I also had to close the tab. But yeah, summoning the tooth fairy.
And that's what we have. Most mammals have just reduced it down to just the two stages, milk teeth and adult teeth. There's one theory that it's because of chewing. So our molars are shaped very specifically to fit together right, and they perfectly fit together. And it's like it's called precise occlusion. Fitting together really well, really hard to do
if you're constantly changing your teeth. Oh yeah, so how do you have that consistent fitting together if that's not the case, And so we think that maybe by evolving one they had to lose the other potentially, But yeah, mammals, basically we just have the two. But people are working on it, right, because we study sharks, We study all
kinds of animals that replace their teeth constantly. Because wouldn't it be nice instead of getting crowns, they just pulled that one out, put like a little stem cell in plant, right, and then have that grow And that's now in progress. People are doing that with mice. They were able to implant a tooth bud and grow a new tooth. It was shaped a little funky, but it did well. It still did well.
They're like, it's a prototype. It's I'll get it next time. It's fine, I'll get it next time.
And the thing is like, teeth are really complicated, especially ours. This is why implants don't work very well. They still work, guys, it's better than nothing, but they don't work very well because they don't have the nerve and the blood supply and the pressure sensitivity anymore. So sometimes people bite too hard, break their implants, et cetera. So yeah, it's just it's never as good as your original organ, right.
Yeah, you mentioned salamanders.
Hit me.
Salamanders have teeth.
Salamanders have teeth, little nubbuns, tiny too, tiny, tiny little things eating bugs, eating ants, mostly worms. They're kind of like just velcar on the inside of the mouth, so everything goes the right way and not out the other way because like salamanders also don't have a secondary palette, so the way they're breathing, the way they're eating, all of that is just in one area. So you really want your worm to go down, yes, not back up? Right? Yeah?
What about snails have those like raspers, what are they called radulas?
Yeah?
Are those teeth?
They are not teeth. Okay, we found the boundary and how do we know they're not teeth. They're not made of the same stuff. They're actually keraten It's like a little pad of velcro kind of thing, little hooks that's carotenized. Yeah, not not adontoad's, which are a vertebrate only thing. Yeah, so true, teeth and adontod's in large startup vertebrates. No invertebrates have them. They have similar things. I mean, things have gotta.
Eat, right, but just not an actual addanta. Going back to replacing teeth, like sharks replacing teeth, it seems like that would be really expensive to use those minerals to regrow, right, but it was worth it because what they would chip off a lot.
We assume. So that's a really yeah, that's a very good point. So why replace so many teeth because, like you said, it's super expensive. Also, maintaining bone is really expensive. So we always assume that something that is hanging around or has been successful through this much time has to be helpful. And the assumption is that, yeah, they're probably chipping their teeth so much. Also, mammals have really thick enamel.
We have really thick enamel, but most reptiles fish have pretty thin enamel comparatively, And maybe that's just because they're making them and tossing them, you know, or the reverse is true. Because they have thin enamel, then they need high replacement.
Do crocodiles and alligators those their teeth, Oh yeah, they do.
They constantly replace their teeth contant don't.
Do you find them in fossilized Oh.
Yeah, oh yeah, they make up like chunks of the freshwater fossil record. What about dinosaurs replace their teeth constantly.
Really because mammals hang on to them. Do you find a lot of dinosaur teeth fossilized?
Oh yeah, oh yeah, tons, yeah, yeah yeah.
Where do people ever just come across them if you're in the.
Right place, yeah, absolutely, yeah, yeah yeah.
If you find a dinosaur tooth, you should call a paleontologist there, right.
Yeah, always call somebody or at least look it up, see where you're at, especially if you're like anywhere near public lands. You shouldn't probably be picking them up in the first place because the context is part of the science. So like where you found it, what's arounded, et cetera. Not all teeth are super valuable to science. So like a lot of shark teeth, we have just tons, yeah,
some some dinosaur teeth. So like I was working, I was in Alberta for a bit and we found a whole hadrosaur dental battery and hadrosaurs merge a bunch of these really thin leaf shaped teeth into like a brick
and then chew with the brick. Ooh, yeah, because they want to like chew a lot of plant matter with multiple tissues at once, right, So they use multiple teeth that wants to kind of chew and grind against this big brick of teeth, And so you find them all over the place because they fall apart when the animal's dead because they were held together with ligaments.
What about deer teeth and herbivore teeth.
So herbivore teeth are really weird, particularly deer and what is it, horses and camel, anything that eats a lot of abrasive material. They use something called cementum as how they attach their teeth. They basically chew on multiple tissues at all times. If you've ever seen like a deer tooth, it's like wavy at the top with like little pits. They want these cusps to be pointy and they want
the pits to be deeper. And how you do that is have some harder tissues and softer tissues and so that way you're like basically making a greater for the plant matter.
Yeah, do they replace those teeth or no?
Those same as us. They're mammals, but.
Rats and otherworphs do theirs. They keep growing to sharpen, right.
So only their incisors, and lagomorphs and rodents are very special in that they don't replace their incisors the front two like yellow teeth, but they grind them against each
other to sharpen. So like people who have rabbits as pets will realize that, like, if I don't give them enough stuff to chew, now I have to trim their teeth, which is such a wild thing to think about, I know, right, But that's because they're ever growing and they'll actually like curl and like grow into their own pallets if they're not taken care of properly. But yeah, that's ever growing teeth. But the rest of their teeth, one set of milk teeth, one set of battle teeth. That's it.
I wonder if they ever swallow them when they fall out?
Oh sure, yeah yeah, dogs and cats do too. Yeah pop mount yeah, yeah, comes right there. And if you want to hear fun fact, yeah, rodent teeth, lag morph teeth. Why are they yellow?
Different material, more dentine, iron, iron in their enamel, so much stronger, so much stronger. I love that they're not just dirty.
You know. I'm so happy they're taking care of their dental height. Yeah, but it's just an adaptation.
It's not just turmeric, you know.
But yeah, that's how beaver's like get through giant trees without destroying their enamel. They have it on one side and so it's just like it keeps that really sharp edge.
Just a bevel. So yes, we have an excellent urban rodentology episode with doctor Bobby Corrigan all about sewer rats and why you should love them in it, I cry, as well as a servitology episode about deer and a beaver episode about how and why rodent teeth are that striking sunset color and how one side of the tooth is iron enriched and tougher leading to a kind of
shive sharpening happening on those two front incisors. And for patrons thirs staying for more knowledge, like Sonia Bird, Alexander Rambo, Lulani and Chris Curious, please report to the beaver and the rat episodes at once, So many good questions about a topic that none of us knew existed until today.
Let me see, I can't believe you're doing this without caffeine.
Absolute champ painful I'm not gonna lie to you, Okay, just a quick dip into other animal teeth. Hats off to patron Shawn who prompted me to learn that marsupials are packing forty to fifty teeth, with the extinct marsupial or pouch lion by the colio having weirdo beautiful rodent like front thangs. Okay. Sean asked, why are marsupial teeth
so much different for most creatures we know? Do you find a lot of different teeth in areas like Australia that's just its own continent and the b asked, it seems that a common problem with human teeth is overcrowding. Is this specific to humans or is there evidence of this and other animals? Like do they have any wonky occlusion just like on accident?
I mean yeah, pathologies happen usually if something happened in childhood or depending on how poorly we bred them. See bulldog skull, see chihuahua skull, see a lot of domestic dogs and persian cats. They just lose space and the genetics to make the teeth are still there, and so the teeth keep being made.
I'm not supposed to do with these, But why do we.
Have wonky teeth? Right? One thought, there's a few studies on this because most animals don't have overcrowding. Most animals have enough space for their teeth, and that's been selected for pretty intensely, right, you got to eat well, That selection pressure is probably lifted for us one because we're social animals. We feed each other, you know, we make mushy food for like elders who do not have teeth anymore.
There's ways that we adapt beyond needing perfect occlusion. The other thought is that we've, through evolutionary time, have softened our diets, and having a really hard diet helps you grow your jaw bigger and so like, basically your jaw growers properly, has enough space and your teeth are not overcrowded. You know, people will counter that with but I don't want to give my baby like a whole bone to chew on, which fair, I mean, choking hazards are not great,
but look how perfect their jaw could have been. But yeah, it's thought to be potentially because of general softening of our diet.
And with dogs, when you give them bones to chew cooked no good because it's splinters, right, Are you cooking out these binding collagen fibers? Is that what's going on?
Yeah, and you're weakening, You're weakening the mineral bonds as well, so it just storts of like fragment. Also, like if you see a bone out in the sun, if you're like walking in the desert or whatever, it looks like almost wood. You're like, yeah, fragments so much. Yeah, it's the same thing. It's the heat impact just slowly. Yeah. And we see it on the fossil record too. That's how we know if something's been buried right away or sat out in the sun for a long time and
then got buried. So you can see like literally dinosaur bones that are like fragmented and look like wood.
Ooh. I never thought about a skeleton being fossilized. I always just thought something just ate shit in the mud and then it was game over.
No, I mean things die there and then get flooded over or buried.
Secondarily, yeah, okay, Danny the dino, because it's a dino. Well, last Patreon question, what unexpected information can we gain from fossilized teeth beyond diet? But I want to know diet wise are you learning a lot about what they ate just based on their nubbins or their fangs.
So on diet, we know a bunch about what animals ate based on their teeth in general, just morphologies. So people will actually quantify the shape and then be able to be like, Okay, this is best for this kind of diet or this kind of diet. But also especially more recently, people are taking the enamel analyzing the isotopes in there, so maybe you can explain what isotopes are.
That is all I'm here for. So, yeah, isotopes are atoms. They're kind of like siblings of the same element. So every element on the periodic table has to have an equal number of electrons the very lightweight little orbiters around the center cluster or nucleus, and the nucleus is made of positively charged protons and neutral charged neutrons, and those are the same weight. They're much heavier than the electrons, so the number of electrons and protons have to be
the same. But an isotope is the same element, but kind of like the sister, it has a different amount of protons and neutrons, so its mass is a little different. As an isotope form and an isotope can emit radiation or not, but they are helpful in paleodetective work.
But basically they can find isotopes that link to diet. So now we know that some dinosaurs we're eating like C four plants or like this type of plant, or we know they ate more seafood because that has a different type of isotope. So teeth shape wise will inform diet chemistry wise will also inform diet.
Super interesting, and this is in their tissues and not just like plaque around it.
Correct, Yeah, it's the actual enamel that holds onto it because basically these animals are replacing their teeth all the time, right, so constantly, whatever they're eating is what's getting incorporated into their tissues and then expressed in their enamel as they make new enamel. So it's kind of like a continuous dental history, continuous chemical history.
You are what you eat, Okay. The most annoying thing about your job I'm getting, can I guess? Yeah? I'm so curious funding funding or do you get emails from people who tried to convince you that dinosaurs didn't exist?
I don't, although my last my most recent paper did get covered in a creationist article.
What did they say?
Well, they said that I needed Jesus. They said that what is it? Teeth have been around forever and therefore my study was wrong and I hadn't considered this and that, and that I needed Jesus, which is pretty funny. I think it was like one of the only citations we've gone for the paper so far. But yeah, well it's a pretty new paper, but it was hilarious. It was pretty good. I can send it to you.
It's hilarious, dear, Okay, Let's dive into her twenty twenty five Nature paper once again titled the Origin of Vertebrate teeth An Evolution of sensory exis Skeletons, in which lead author doctor Yara Haridi establishes quote here. To resolve controversy and understand the origin of dental tissues, we synchrotron scanned
diverse extinct and extant vertebrate and invertebrate exis skeletons. We find that the tubules of a Natalypsis have been misidentified as dentine tubules and instead represent a glasspited arthropod sensory sensilla structures. What does all that mean, let's gossip about it.
And so one of the things I really wanted to look at was this early fish from the Cambrand thing, and so people found it and thought that this was the earliest vertebrate, and I was like, great, we're gonna image this thing with this all this new methods that we have. So I now use a particle accelerator to
image fossils. No I've heard about those. No, Okay, So synchotrons are these rings that you accelerate an electron in and then you basically shoot X rays from the bending of those two fossils, and it's basically like one hundred billion times stronger than your doctor's X ray, really strong, strong enough to get through rock. Oh my god. People use it for like batteries, people use it for all kinds of things. We used it for rocks, and I was like, Okay, I want to shoot these really early fossils.
Let's see if these like early fragments really are teeth, because then that would pull back the record of mineralizing vertebrates from middle order vision all the way back to the Lake Camberan and it would be my transitional fossil that I was looking for right, Oh my god, this is what I pitched to come to U Chicago. I was like, this is really what I want to do.
The fossils exist somewhere, let's go find them. And so they've been published on before, in the nineties seventies and then again in the nineties, and they were like a big splash every time because brand new early vertebrate.
Hm.
We scan them and I was like, great, this really looks like a tooth. These really look like little odontods and a piece of bone. Wonderful, we have brand new, really beautiful three D images. Gorgeous. Okay, great. I dig into the literature some more, and at that time, even when they originally published them, they thought, maybe these are not vertebrates, but maybe these are arthropods.
Because remember, we just spent the last hour establishing that invertebrates like arthropods with their exoskeletons, do not have odontods. Right, we know those words now, so why are we seeing them?
And everyone who said it was that arthropod kind of got like brushed aside, and another paper came out that used paleohistology to prove that they were vertebrates. And how they did that was they cut up these little fragments and saw the inside of the odontod and they saw these tubules inside the adontod and so they were like, this is denteine, and dentine is only found invertebrates, and
therefore it has to be a vertebrate. Slamm dunk, big deal came out, and everyone's like, okay, great, we now know this Late Cambrian fish thing, fragment thing is a vertebrate. But I was like, okay, I want to scan it now that we know it's a vertebrate. Let's get a good three D structure of these earliest teeth. When we scanned it, I was like, great, this does look like
a tooth. And then I started reading some more and I was like, well, the people who originally published that it was an arthropod are really good scientists and I respect these people, and what if they were right? What if? You know? So we scan some arthropods to compare it to and we start scanning these arthropods and we see tubules, little little tubes, and so these arthropods have also bumps on their skeleton, and we're like, this is odd. And each bump has tubules and it's really hard and we're
like what if. So we scan a bunch of arthropods and basically, long story short, found out that this late Cambrian guy was not a vertebrate no at all, but an arthropod. So what does that mean exactly? So what that means is that we don't have our transitional fossil, We don't have the guy in the middle. We still have this giant gap between squishy boys and fully armored fish. And that was really weird and it really bothered me. I was really upset. Yeah, I was like, oh no,
my tooth, my earliest tuth. But even at that moment, I was like, why does it still look like a tooth? Why are these arthropods covered in things that look like a don to toad's?
Yeah?
And what are they? What are these like weird bumps that look like adntoa's on an arthropod versus a vertebrate.
Yeah.
So I did some deep digging, read way too much about arthropods and found out that there are these things called sincilla. Sincilla are sensory structures that are super diverse. So like, think of like a fly that lands and he's like rubbing his little legs and there's hairs all over it, like you know the movie Fly.
Yeah, yeah, yeah, I said it, yeah exactly.
So that's a type of sincili that's a mechano sensor one, so it can sense the deflection as they move. There's chemistry ones like chemo sensory ones, so they touch the ground, they taste the ground every time they land, of course, but that's what sinceillly are, and that's what we found on this ancient arthropod from the Ladies Cambrian. It was sensory organs all over their bodies and so we're like, oh, that's really bizarre. So this is really intricate sensory network
of like bumps and stuff on Arthur POD's fantastic. I go and I tell Neil, my supervisor, and I'm like, hey, I think they're there. And he's like, oh, well, that kind of makes sense that they look like teeth. Then that makes sense that they look at like adonods. I'm like, why does it make sense mm hmm, and he's like, well, because teeth are sensory, adontods are probably sensory too. And I was like, how do we prove this? How do we actually test if odontods, which are outside the mouth
are sensory the same way teeth inside the mouth are. Yeah, you know your teeth are sensitive, right, of course you're having some issues with that, and like a lot of us do, But it doesn't really make sense. Why would you chew with these super sensitive structures. Yeah, that was always such a bizarre thought process. But then you look at all these different animals that use their teeth as sensory Organs, elephants touching the ground, narwhals with their giant
like horn. It's not a horn, it's actually a giant tooth bonkers, and they sense all kinds of temperature changes and wave changes because they're Denteine is sensitive. Dentine is our sensitive tissue. That's why if you take care of your enamel and your gums, usually your teeth are okay, because when you're denteene is exposed, it's the sensitive tissue.
Oh no, okay. So now we know adon tooads have dentine, and we know that teeth have dentine, but we don't know if adntoad's outside the mouth are sensitive mm hm. And so this is where I took a really weird tangent that I want to tell you about. Remember when I told you that sharks have a dantoad's, they're covered in these little little bits. The other ones that have a danto's are cat fish and so you know, like a little pleco those like algae eating little fish that
you get in your aquarium. Yeah, so those guys are covering nadanto's too. They're covered in little teeth. What's the bizarre And they are super easy to keep and super common. So I went to a pet store and I got a bunch of them, oh my god, and started breeding them in the lab to get their little embryos so we could actually test if their dontods are innervated, because that would be the first step for them to be
actually sensory. If the dantod has nerves going to it, then at least that's step one of it being innervated. And these dantods in our early fish from the Middle Ord division have pulp cavities, and pulp cavities are where the nerve goes, and we were able to trace it all the way down to know that, like there had to have been a nerve there. But do modern dantods outside the mouth have nerves? So went collected a bunch of these algae eating pleco learned how to keep an
aquarium because God knows, I never had an aquarium. Uh, and write a bunch of these little fish. And then we use this amazing method called clarity where you make the little embryos super clear. You basically remove all the fats and lots of the proteins, and then you add antibodies that attach only to nerves and then they have
a fluorescent probe so they glow under a microscope. And so you bathe them in these antibodies and you put them under the microscope and then they glow wherever the nerves go, and you can trace every nerve to every adontoad. All their adontoads were innervated right into the pulp cavity.
No.
And so when they're in the aquarium, are they like, oh it's a little cold in here? Is that what they're feeling is that.
They fight with them? What do they do? They have cheekadon tooads that are on this Like catfish are really weird, guys. I'm just gonna side note everybody. I think it is it one in five vertebrates is a catfish?
No?
Please, check me on that.
Your later told me that she meant one in twenty or five percent of all vertebrates are catfish. One in twenty vertebrates on planet Earth are catfish. What the fuck's going on? So, yeah, we need a catfish expert for a Cilia formology episode, And yeah, I think it needs to be a two parter addressing internet scams as well. Maybe five percent of vertebrates on dating apps are bots. Who knows anyway, actual real, slimy, perfect whiskery catfish.
Their diversity is wild. Yeah, no, they did really well for themselves. Not all of them have adanto's, but these little algae eating ones too, and they have them all over their bodies, all over their fins, all over their cheeks, and they ram each other with them. They also sense their environment all the time because they're bottom dwellers, right, so they're always feeling the bottom and they're tasting with taste buds in between their adontos. They taste their environment.
Have you ever wondered when you like, if you put a little bit of food somewhere in your aquarium, even if it's far from your fish, still nowhere to get it. That's because they're constantly kind of tasting their environment.
With taste buds in between their outside teeth.
Seems that way. Yeah, why don't.
Sci fi movies just do a just do biology. Yeah, just dom horrifying and amazing.
Yep, yep, yikes.
And so what happened when you were writing up this paper?
So it was like a bunch of different parts, Right, We made an arthropod library where we did comparative stuff. We found out that they were sincilly. Then we did a bunch of stuff on sharks and catfish to find out thedontoads were innervated, and then tied it all back to the Ordovision vertebrates. So this paper we basically said
the Late Cambrian supposed vertebrate is not a vertebrate. So we kicked that out, which meant that now our true earliest mineralizing vertebrates, our Middle Ordervision four one hundred and fifty or so million years ago, and we finally have a little bit of that. The external dantodes were not only for protection, they weren't only for being armor, but they could have also helped our ancient ancestors with sensation, and that maybe that explains why our teeth are sensitive
in the first place. Maybe it's because it's an inherited complexity from their original function.
And I tell my dentist about this. Do you try this?
I tried. I just had a tooth cleaning and actually last week and I'm like, hey, I'm so happy because I'm proud of my paper. And I'm like, you want to know something, and they're like, please open your mouth, please please, ma'am. They shut me down so quickly.
You're like, you work with teeth. I work with tea slightly different era. Everyone pass this on to your hygienist. They deserve cool facts and a lot of praise. People should know. But yeah, we were talking, Okay, what were we talking about?
But no, I would say the hardest part, that was the question. Hardest part about my job is that I have to keep thinking about ancient fish while the world is doing what the world is doing. Yeah, and I think that would be the hardest part. Funding has obviously become a problem recently for a lot of scientists, particularly
natural history, particularly life earth sciences. It's just, you know, when everyone starts to panic, they think that it's time to cut science, and that's actually the worst time to cut science in general because we need to preserve these things. New discoveries are how we get out of economic downfalls,
et cetera, et cetera. So that's always sad. But I think the hardest, hardest part is just I guess I think about old bones today, even though you know bombings are happening or economic crashes are happening, and then the system that's supporting me and celebrating me is also the same one that's upholding all kinds of other issues. So yeah, I think it'll be the hardest part.
Just you're like a head down yep, don't mind the wars, the genocides, the climate change.
Yeah, and that's tough.
Yeah.
The way I get over that, though, is like through stuff like this science communication. I really do see a difference when you talk to people. Most people haven't met a scientists. I sure didn't until I was like about to become one. So I don't want to leave it all doom and gloom, because, like I push people, I think the real solution to this is more people interacting
with science. Just go to your museums, go to your universities, go volunteer for whatever invasive we'd thing that people are removing from your local neighborhood, interact with science as much as you can.
And there's always community science too for people to join.
Yeah, right, totally. And there's like big science fairs, big volunteer opportunities.
Yeah, get in there.
Yeah, but.
I mean, how do you even say what the best thing about your job is When you're getting to look at all this cool, weird stuff, what's your favorite part? What gives you like, odonto goosebumps.
Don goosebumps. That's disturbing, but accurate. I would say, like looking at the tissues under a microscope, realizing that you're the first person to see this animal since it got buried. You're the first person to put these things together. Fossils just like the actual physical objects, the fact that they exist is amazing. The new methods, the people I work with, like,
I love my job. I love my job. I want everyone to experience the feeling of finding their first fossil, because that's it's so weird to just crack open a piece of rock and be the very first person to look at this bone since it was buried four hundred and eighty million years ago. Like, that's such a bizarre feeling. And if you literally sit with it and you let it like permeate your being, you realize how special that is and how small we are and kind of making
ourselves small. I think in many ways, like I don't know, it makes you feel like you're part of a big system and time and the earth and all of that comes together to make this particular moment where you're seeing this fish. It's just weird. Discovery is always so so interesting. The amount of mental freedom that we have to ask strange questions and go down strange rabbit holes. It is an eighty h deer's like dream, which is why there's
so many of us in academia. Yeah right, yeah, so, I mean I love my job.
When you think about things in the long term, ex essentially not to doom and gloom it, but if you could fossilize yourself after death, would you like, do you want to keep your bones around or are you like throw me in the ocean, burn me up, and grind me up. I would think about bones differently, where I'd be like, I kind of want my skull to be around after You.
Can't do it to science, and then you know you'll probably end up like a kidaver or an anatomy lab and that's always really really helpful. Sometimes you'll end up as a teaching skeleton. I don't know how to end up as a teaching skeleton, but I would love to end up as a teaching skeleton.
Wouldn't be cool.
It would be so cool. I don't find it like obviously. I mean, I work with bones all the time. I don't find a grotesque. I find it so fascinating. Yeah that, like everything is such a different shape, and you know, my skulls. I can be hanging around in a classroom staring at students forever. I would love that.
I think that would be cool too. Now that I've been talking to you about bones, I'm like kind of worried to that. Yeah, if they can use me, or just put me in a mud flat and uh and let.
The octopus aliens find me. Yeah, I'm with you.
Just a little peace sign on a mudflat, perfectly fun.
Slap me over, yeah, no copin, please just wet wet mud.
Uh. This is a joy. And I'm so glad this has been six years in the making.
At least at least you know you're doctor.
Thank you for having me at this beautiful, terrifyingly dark maze of cabinets known as the Collections of the Field Museum. They're so long, Oh my god, what an icon. So ask informed people on a bashed question because their skulls are full of good stuff. Thank you so much, paleohistologist doctor Yara Haredi for opening up the stacks at the Field Museum, for this visit, changing the way I gaze at my own teeth, and for more on Doctorhurridi. Her
website is Yara Heredi dot com. Her instagram is Yara Underscore Haredi. And we'll have more links to the studies and the some here project at Aliward dot com, slash Ologies slash Paleohistology, and remember we also have kids safe, classroom appropriate cuts of Ologies classics. They're out every week. Just search Smologies s M O l O g I e s and subscribe wherever you get your podcasts. We are at Ologies on Blue Sky and Instagram. I'm at
Aliward on both ologies. Merch is available at ologiesmerch dot com and to submit questions before we record, sign up for a dollar a month at Patreon dot com. Slash Ologies The Lovely aeron Talbert Adminsiologies podcast Facebook group. Aveline Malik makes our professional transcripts. Kelly Ardwyer does the website. The Smiley Noel Dilawarth is our sking producer the web. Holding us together as managing director Susan Hale and working as a set to chew through the edits are Jake
Chafe and lead editor Mercedes Maitland of Maitland Audio. Nick Thorburn made the theme music. And if you stick around until the very end, you know, I'm gonna tell you a secret and this week it's two. So one app I've been loving lately is called Doodle and I'm not getting paid to talk about it. It's in beta right now.
It gives you a prompt every day to doodle something, and then you can see what your friends are strangers doodled on that same prompt and it's a very fun, low key way to just make something no stakes and let your brain be goofy and creative once again. It's free. It's called Doodle no e on the end, and my wonderful friend Stephanie is the designer. I think it's a genius. I'm on there as squirrel hat with a K sk
W skw rl hat I think. And my profile picture is a bat face again not getting paid doodle, just love it. Second secret, which is a bit more vulnerable. I feel like I'm going to regret this as soon as we hit publish. But I used to act on TV. That's how I got my health insurance. And I once had a bit part on Grey's Anatomy on an episode called Something to Talk About, in which I play a
pregnant wife with a mysteriously pregnant cisgender husband. So if you would like to learn some dramatized medical trivia, do enjoy that. Don't make fun of me too hard. Also, the belly they had me wear was like a pantyhose, big girdle, and it was filled with like ten pounds of bird seed and it was fun to squish it with my finger. Also, I had baby banks and blue black hair, So enjoy that. Okay. So those modern teeth,
they evolved so hard and they deserve it. Wear your mouthguards, black eyes for.
My pacodermatology, homeology or do zoology, lithology, technology, meteorology, paratology, apology, seriology.
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