In our 94th episode, we had the pleasure of talking with Dr. Dave Varricchio from Montana State College.
Episode 94 can be about Raptorex, a tyrannosaurid that some assume could also be a juvenile Tarbosaurus.
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On this episode, we focus on:
- The dinosaur of the day: Raptorex
- Identify means thief king
- Doubtful tyrannosaurid genus
- Kind species is Raptorex kriegsteini
- Species identify is in honor of Roman Kriegstein, a Holocaust survivor (son Henry donate the specimen to the College of Chicago to be studied)
- Described in 2009 by Paul Sereno and others
- Tyrannosaurid Skeletal Design First Advanced at Small Physique Measurement, printed in 2009
- Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia, printed in 2011
- Thought-about by many to be a nomen dubium as a result of tyrannosaurids have a tendency to vary so much whereas rising, and there’s no grownup skeleton to check it to (it appears much like juvenile Tarbosaurus); additionally initially it was regarded as from the Yixian Formation in China, and about 125 million years previous, however now that’s regarded as unlikely
- Specimen was collected illegally and smuggled out of Asia
- Pete Larson, who tried to determine the origins of the specimen, mentioned an American businessman purchased it from a Mongolian fossil vendor, after which offered it on the Tucson Gem, Mineral and Fossil Present. Dr. Henry Kriegstein, a fossil collector, purchased it (on the time it was described as a juvenile Tarbosaurus) and he advised paleontologist Paul Sereno about it, who mentioned it was a subadult of a brand new species from the Yixian Formation. He printed an outline and organized to ship the fossil again to China, the place he thought it had been smuggled from
- Sereno mentioned it was about 6 years previous and almost an grownup
- If that is true, it will imply that tyrannosaurs began as small animals with a big head, lengthy legs, and two-fingered arms, as an alternative of evolving into giants with these options. However earlier proof discovered that primitive tyrannosaurs had small skulls and lengthy arms with three fingers on every hand
- In 2010 Pete Larson seemed into the fossil and mentioned it was most likely a juvenile Tarbosaurus, and possibly didn’t come from the Yixian Formation (which Sereno had concluded based mostly on a fish fossil discovered alongside it). Larson mentioned it could have come from Mongolia as an alternative, from formations solely 70 million years previous, and mentioned they wanted “a extra detailed evaluation of the fossil matrix, together with courting any pollen related to the fossil.” Sereno mentioned he nonetheless believed in his authentic evaluation
- In June 2011, an in depth second examine was printed in PLOS ONE by Denver Fowler, Pete Larson, and others, they usually discovered that the specimen was solely 3 years previous as an alternative of 6, and located that the fossil Sereno used thus far Raptorex, of a Lycoptera, was truly greater than any identified Lycoptera and was most likely a part of an ellimichthyiform fish, which lived throughout the whole Cretaceous interval, so it’s unclear how previous the Raptorex fossil is. Fowler and Larson and others mentioned Raptorex was most likely a juvenile tyrannosaurid, much like Tarbosaurus, although it’s unclear what genera it belongs to precisely till extra is thought about tyrannosaurid progress patterns in addition to extra details about how previous the Raptorex fossil truly is. If this conclusion is true, then Sereno’s speculation that tyrannosaurid options have been in smaller variations of tyrannosaurs first wouldn’t be true
- In 2013, Newbrey and others mentioned the fish fossil (previously regarded as Lycoptera) discovered close to Raptorex was truly a hiodontid, most likely much like those discovered within the Nemegt Formation in Mongolia (lived within the Late Cretaceous). This implies Raptorex most likely got here from the Nemegt Formation and lived within the Late Cretaceous
- The hiodontid species discovered close to Raptorex match with the species solely identified from the Nemegt Formation
- In 2011, Takanobu Tsuihiji wrote an in-depth description of a virtually full juvenile Tarbosaurus, which helped to check different juvenile tyrannosaurids, together with Raptorex. They discovered that Raptorex and the juvenile Tarbosaurus had some variations, corresponding to Raptorex not having a distinguished crest on its higher hip
- This could imply Raptorex is its personal genus, however Fowler, Larson and others don’t all agree on whether or not or not Raptorex has that crest on its hip (Larson wrote that there’s a “delicate crest”).
- Nonetheless, the concept tyrannosaurids advanced their traits at a smaller measurement appears to stay unsure
- About 9.8 ft (3 m) lengthy and weighed 143 lb (65 kg)
- Had a big cranium, lengthy legs (quick runner) and two-fingered forelimbs
- Had a big mind, and good sense of scent
- Enjoyable truth: Based on Dr. Ken Lacovara within the new VR video; Dreadnaughtus weighed lower than a Boeing 737, regardless of weighing as a lot as 9 T-rex‘s and 12 full-grown male African elephants
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For individuals who might want studying, see beneath for the complete transcript of our interview with Dr. Dave Varricchio:
Garret: So now we’re going to leap into our interview with Dr. Dave Varricchio, who’s a paleontologist at Montana State College in Bozeman, Montana, the place he each teaches and does analysis. He has discovered new details about Troodon, and he’s one of many world’s main consultants on dinosaur replica, which is why we actually needed to speak to him. And Sabrina’s going to leap in half approach via the interview so don’t get startled when she pops in out of nowhere.
So the primary query we at all times ask is do you’ve a favourite dinosaur?
Dr. Dave Varricchio: I really feel it must be Troodon since I labored on Troodon a lot. So I do say it’s Troodon. I’ve Troodon on my license plate on my automobile.
Garret: That’s a reasonably robust assertion when you have a particular license plate.
Dr. Dave Varricchio: And I really feel like I do know Troodon properly within the sense that I really feel like I’ve executed a bunch of various stuff that’s concerned Troodon, so it’s […] (00:00:51) I do know greatest, it’s extra, I’m conversant in it moderately than it’s the world’s greatest dinosaur is form of how I have a look at it.
Garret: Gotcha, cool. Talking of Troodon, I by no means know how one can say it. I hear TRU-adon, I additionally hear TRO-odon, however I’ll go along with Troodon since that’s what you’re saying. What all have you ever realized about Troodon via your research and analysis?
Dr. Dave Varricchio: So there was some histology work, in order that seemed kinda at growing older of people, progress of people, it appears like Troodon was comparatively fast to achieve full measurement perhaps 5 years, however perhaps it took a little bit bit longer to actually finalize its progress. it type of half-sized by 12 months one and almost full grown by 12 months three. Although there are a number of bits on the market of some, right here or there there’s some scattered bits of troodons that instructed there have been some actually large people which puzzles me. After which there’s an entire line of labor involving the Troodon replica, so I really feel like we’ve a reasonably good understanding of troodon replica as a result of we’ve a nesting hint, we’ve egg clutches, we’ve good eggs, we’ve embryos, properly preserved eggshell, so I really feel from that we’ve a reasonably good deal with on Troodon replica.
After which there was a bone mattress that I labored on the place there was an abundance of Troodon materials, though I don’t actually perceive precisely what meaning. It’s form of fascinating.
Garret: So whenever you say a extremely massive Troodon, how large is that?
Dr. Dave Varricchio: Usually we are saying a Troodon is about 50 kilograms, so someplace round 125 kilos. However on occasion, we’ve this one actually large tibia that’s I don’t actually know weight sensible what that might equal nevertheless it appears I don’t know considerably bigger, like perhaps twice the mass or one thing like that. And there’s the one bone on the College of Montana of their collections that appears actually large, however the remainder of it type of appears to hover across the similar measurement. I don’t know if that’s completely different taxa, like perhaps there’s a unique troodontid that’s greater, however we don’t actually have proof for smaller people of it if that’s the case. Or perhaps it’s simply exceptionally massive people. I’m not likely positive what meaning.
Garret: Cool. Is Troodon principally identified from Montana? So do you’ve entry to numerous the Troodon specimens, or is there a fairly large space the place you discover them?
Dr. Dave Varricchio: There’s some materials from Alberta, so simply throughout the border mainly, and so right here and in Alberta there’s different materials. There’s enamel which have been scribed from as far north as Alaska and down in Mexico which might be referred to as Troodon which might be form of difficult to take care of in that one particular person would have a variable set of enamel from entrance of the jaws to again of the jaws. So it’s laborious to know when you have like a tooth, does that symbolize a unique species or is that throughout the variation that you simply discover inside Troodon? So it will get referred to as Troodon as a result of we don’t actually have anything to name it. There’s some materials from Utah that was described as talus is the genus. Fairly much like troodon as properly although too. So sure, backside line is many of the materials comes from Montana and southern Alberta.
Garret: Okay. There are numerous them proper? I believe I see a good variety of Troodon finds.
Dr. Dave Varricchio: Probably not. I imply we don’t, for some motive it looks as if there’s good cranial components in Alberta. They’ve some good mind instances in Alberta. And we’ve higher […] (00:04:16) cranial stuff in Montana, however there’s not likely a whole skeleton for Troodon. I imply probably the most full skeleton is a small juvenile from Montana.
Garret: Yeah that might be problematic whenever you’re making an attempt to determine what the utmost measurement is.
Dr. Dave Varricchio: So it’s a lot rarer than T-rexes. For my part there’s tons of T-rexes, there’s a number of actually good skulls of t-rex, and you may’t say the identical of Troodon.
Garret: Is that as a result of it might need been extra like prey-sized, or why do you assume that’s?
Dr. Dave Varricchio: I believe there’s a bias towards smaller taxa might be one side of it. Is that what you imply by prey measurement, that folks eat it?
Garret: Yeah.
Dr. Dave Varricchio: Yeah, in order that’s a part of it. It most likely is a predatory animal, so most likely when it comes to inhabitants it’s most likely not an considerable animal as properly. versus say a Maiasaura or another duck invoice or ceratopsian or one thing like that, that there may be many extra in a given ecosystem than Troodon.
Garret: Sure we have been truly on the Museum of the Rockies two months in the past, and we noticed your Oryctodromeus, or properly I say your Oryctodromeus as a result of I believe you have been most likely the paleontologist who most likely had probably the most enter on what it seemed like, the show. What do you assume Oryctodromeus might need been digging for? Do you assume it simply dug for like making a home, or do you assume they may have dug for different issues?
Dr. Dave Varricchio: it’s fairly fleet of foot, it has fairly lengthy gracile hind limbs. it’s form of, I suppose in my thoughts constructed like a coyote or a Patagonian mara. It’s form of a bizarre rodent in South America that’s form of long-legged but additionally digs dens. So should you noticed it you can say oh that appears like someplace between a miniature antelope and a jackrabbit. It’s a fast-paced operating animal nevertheless it digs dens, so I believe Oryctodromeus is kinda like that. I believe it’s simply denning underground however not, I don’t assume it’s feeding underground. However perhaps they’re essential for replica.
Garret: Would that simply be for like show or what do you assume?
Dr. Dave Varricchio: No I simply imply like a shelter away from predators.
Garret: Oh, gotcha.
Dr. Dave Varricchio: So like a spot, only a secure haven for offspring. I don’t know, eggling, stay delivery, I don’t know what it’s doing in there. However I suppose I really feel prefer it’s most likely a secure shelter.
Garret: So the one which they discovered, it was simply in its personal burrow, it didn’t have any younger or something with it?
Dr. Dave Varricchio: No there have been two, components of two juveniles with it.
Garret: Oh okay, however we don’t know if there have been eggshells.
Dr. Dave Varricchio: No, no eggshells that we discovered, no. I imply they’re pretty good-sized in people in order that they’d have been out of the egg for fairly a while, , like months.
Garret: Fascinating.
Sabrina: That is the one burrowing dinosaur we learn about proper?
Dr. Dave Varricchio: Bob Bakker described a small ornithischian dinosaur that he mentioned he thought got here from burrows about 10 or 12 years in the past, nevertheless it’s a small ornithischian as properly. He thought that it may be burrowing simply due to the character of the, he didn’t have a burrow construction however he had these assemblages of small people collectively, and he thought that was a technique to clarify them.
Garret: Oh fascinating.
Dr. Dave Varricchio: So he instructed that for that animal. He didn’t actually go into a lot particulars about it taxonomically or like I mentioned there was no hint to go along with it. And it’s fascinating I really feel like there’s now rumors, I can’t actually say, of different dinosaurs that probably might need been burrowers.
Sabrina: Yeah it will make sense that there’s multiple sort that did that.
Garret: Yeah, I imply we see numerous trendy animals do it for positive, particularly smaller ones that want a little bit further protection.
Dr. Dave Varricchio: Proper and it’s additionally worthwhile to get out of no matter environmental situations, whether or not it’s the warmth of the day or the cool of the night time, , may be helpful to have a shelter simply to spend these unhealthy occasions in.
Garret: That’s true.
Sabrina: It most likely simply feels safer too. , nobody else can get in.
Dr. Dave Varricchio: Yeah.
Garret: Talking of replica, I haven’t actually heard anyone discuss potential stay births of dinosaurs. Is that one thing you assume may be doable?
Dr. Dave Varricchio: we don’t, I suppose I might say we don’t actually have any good proof within the sense of we haven’t ever discovered a big skeleton with younger inside, and I believe that given all of the analysis that’s been executed on dinosaurs that if stay delivery was on the market we’d most likely discover a type of ultimately. However we do lack eggs for big numbers of dinosaurs, so we’ve a reasonably various set of dinosaur eggs. However whenever you have a look at them intimately they principally fall out with saurischian dinosaurs. So we’ve , we’ve oviraptor eggs, and we’ve troodontid eggs, and we’ve eggs for different small theropods, we’ve eggs for sauropods, however we’ve no eggs for armored dinosaurs, we’ve no eggs for horned dinosaurs. , so these are two large teams. After which ornithopods we’ve eggs for hadrosaurs however not any of the basal ornithopods. So there’s some large chunks of the dinosaur tree the place we don’t have eggs. I’m undecided what meaning. Does it imply that they’d soft-shell eggs or they’re nesting in a approach that doesn’t protect the eggs, or they destroy the eggs? So if they’ve mushy shell eggs, after you have mushy shelled eggs there’s type of the potential to haven’t any eggs in any respect I suppose.
Garret: Yeah.
Dr. Dave Varricchio: In order that’s what you discover amongst lizards. , yow will discover like amongst lizards stay delivery evolves a number of occasions, and in carefully associated taxa there could be one which lays eggs, normally mushy shelled eggs, after which one other taxa that has stay delivery.
Garret: Would there be any large benefits to having a stay delivery in contrast with laying an egg?
Dr. Dave Varricchio: I suppose a few of it’s that when you have stay delivery probably you might be defending the eggs all through the incubation interval versus digging a gap and laying your eggs and leaving them there. They’re subjected to environmental situations, to scavengers, issues like that which may come by and raid the eggs. However when you have the eggs internally then they’re protected throughout that interval.
Sabrina: Fascinating. I used to be simply fascinated about how like with penguins and it’s such an ordeal for them with their egg, they usually must, was it the daddy penguin can’t even eat for months at a time as a result of they’re busy defending the egg after which…
Garret: Yeah that’s an excellent level, in additional excessive environments it might be extra useful.
Dr. Dave Varricchio: That appears simply loopy doesn’t it? It’s like they spend the winter standing on an egg within the coldest a part of the world.
Sabrina: Yeah simply ravenous to demise.
Garret: Yeah.
Dr. Dave Varricchio: Yeah it’s like not even the summer time down there, it’s the winter. It’s like that appears ridiculous, yeah.
Garret: They might actually go for a stay delivery evolution.
Dr. Dave Varricchio: Yeah I suppose that might facilitate issues. You’d assume if they’d them internally at the least they might swim round within the water, it will be so much hotter, they might feed…
Garret: Yeah they might eat moderately than simply slowly ravenous to demise for months.
Dr. Dave Varricchio: Yeah, yeah.
Garret: So that you talked about there’s a number of several types of dinosaur eggs, and I used to be wanting someday in any respect the completely different sorts of eggs which have been categorised into differing types, and it looks as if dinosaur eggs account for lots of the range of several types of eggs that we’ve found in animals. Why do you assume there are such a lot of completely different constructions and shapes and issues happening with dinosaur eggs?
Dr. Dave Varricchio: I don’t know. I believe that’s a extremely good query. And I agree that I consider dinosaur eggs as extra various in measurement and form and microstructure and eggshell ornamentation than we’ve in trendy egg layers. So it’s actually bizarre I believe that there’s a lot range. May very well be type of like a World Battle I aircraft analogy. I don’t know should you’re…
Garret: I see.
Dr. Dave Varricchio: Do you ever have a look at World Battle I planes, they’re like single-wing planes, there’s biplanes, there’s triplanes, there’s even like quad planes. Like there’s like bizarre, they’ve engines within the entrance, they’ve engines within the again, they do all types of issues. After which by the point you get to World Battle II or in a while just like the aircraft range drops, are you aware what I imply? It’s type of like there’s like a extra customary aircraft format. So I don’t know if it’s like type of a trial, like they’re simply seeing what works and ultimately there’s like some facets that get pruned from it, I don’t actually know if there’s actually an excellent clarification as to why among the completely different morphologies work relative to different ones. As a result of it doesn’t appear, in numerous instances it looks as if properly they’re simply burying the eggs within the floor for this large range of eggs. Like they’re nonetheless in the end simply kinda buried within the floor, so I don’t actually see what they’re doing functionally that’s completely different.
Garret: Oh fascinating, so even with all these completely different constructions numerous them are handled the identical.
Dr. Dave Varricchio: Yeah. I imply there’s some range whenever you get into the maniraptoran theropods, like oviraptors and Troodons. Then they form of do some various things, however the remainder of them seem to be they’re simply type of buried eggs. So I don’t actually know. I believe it’s an excellent puzzle, and it’s a type of difficult puzzles as a result of you may’t say oh properly it matches this contemporary taxa. It’s like oh, these are simply bizarre they usually’re dinosaurs simply doing bizarre issues. And so it’s laborious to know how one can interpret them.
Garret: Yeah, so is it more durable with eggs to form of extrapolate again utilizing trendy taxa than it’s with different issues like say, , lengths of limbs and issues like that? Are there not numerous trendy analogies?
Dr. Dave Varricchio: There’s some common tendencies, like porosity amongst trendy animals. Low-porosity eggs are these which might be laid in an uncovered nest like a chook nest usually, and high-porosity eggs are buried in sediment or vegetation. I believe one benefit that eggs have is you may consider an egg clutch as actually a nesting hint, that’s that the animal organized, , presumably should you’re a clutch that hasn’t been modified after it’s been buried, nevertheless it’s kinda laborious to think about how it may be modified an excessive amount of after it’s buried, however presumably it’s how that animal organized these eggs within the floor. So there’s some purposeful side that’s preserved in that association, and so I believe they’re kinda fascinating that approach. Each how the clutch might need functioned, but additionally fascinated about you know the way the dinosaur dug the outlet after which positioned these eggs in that association is form of an fascinating puzzle too.
Garret: Yeah, as a result of you’ve some very massive dinosaurs laying some comparatively small eggs right into a gap.
Dr. Dave Varricchio: Yeah, and a few of them, numerous them are organized in a single layer, not, like a crocodile or a turtle digs a gap they usually form of simply type of empty all of the eggs into that area and form of pile on prime of each other, however numerous dinosaur eggs are extra organized the place it’s like you are taking six eggs and also you dig a gap and lay all of them flat in that gap, not pile them on prime of each other, after which bury them. And that appears, ya it appears laborious. It’s like how does a sauropod do this? Yeah, it’d be fascinating to observe.
Garret: Yeah particularly as a result of certainly one of their eggs is so small in comparison with their physique, even simply in comparison with like a single foot on a sauropod.
Dr. Dave Varricchio: Yeah in order that they nudge them round with their heads or choose them up of their mouth or, yeah, I don’t know if it’s an answerable query nevertheless it’s form of fascinating to ponder.
Garret: Yeah.
Sabrina: Positively.
Garret: And also you I believe had printed, I believe you have been on this paper, about how typically they bury compost or issues like that to form of regulate the temperature of the eggs whereas they’re buried.
Dr. Dave Varricchio: No that wasn’t me. I believe Jack Horner talked about vegetation. vegetation doesn’t actually protect properly with eggs. The 2 are form of opposed, and the one, rotting vegetation produces acidic situations. Acidic situations dissolve away eggshell. We don’t have a lot proof of vegetation with dinosaur eggs, however that doesn’t essentially imply that they didn’t use it however perhaps it’s, we’re seeing eggs which might be preserved with out it if that is smart.
Garret: Yeah.
Sabrina: Yeah.
Dr. Dave Varricchio: May very well be a preservation bias. We’re type of seeing eggs the place animals didn’t use vegetation.
Garret: Are there any trendy animals that bury their eggs like how dinosaurs do?
Dr. Dave Varricchio: In like the same layer?
Garret: Yeah.
Dr. Dave Varricchio: No. Desert tortoises form of do this. They type of prepare their eggs on a flat floor or different pile. They don’t make very many eggs, there’s solely like 4 or six or one thing like that versus like a sea turtle, like sea turtle that lays 100 eggs all piled atop of certainly one of them.
Garret: However dinosaurs are kinda extra in that quantity proper? It’s normally like eight or so.
Dr. Dave Varricchio: Yeah some are comparatively small. A number of the sauropod nests down in South America I believe have had 20 or perhaps even 30 eggs.
Sabrina: Wow.
Garret: That’s so much.
Sabrina: And did these all belong to at least one?
Dr. Dave Varricchio: Properly there’s some debate from […] (00:17:05) the place they’ve tons of clutches, and among the clutches could also be superimposed on prime of each other. However a extremely large, I imply they’re a number of ton animals so actually the mass of all these eggs shouldn’t be very a lot relative to the mass of the grownup.
Garret: And then you definitely mentioned a few of them ultimately did evolve open-nesting conduct and which may have some form of evolutionary benefit proper?
Dr. Dave Varricchio: Yeah, so oviraptors and troodontids seem to have some contact between the grownup and the eggs throughout the clutch. Possibly there’s much less so in oviraptors after which extra contact in troodontids.
Garret: Oh fascinating.
Dr. Dave Varricchio: So it’s a debatable level however I suppose I believe that meaning they’re offering warmth to the eggs and incubating them with physique warmth, or at the least partially with physique warmth.
Garret: That’s fascinating you say Troodons had extra contact contemplating once I consider an oviraptor one of many fundamental issues I consider is that brooding form of mom that was discovered.
Dr. Dave Varricchio: Yeah, however the grownup type of sits with its ft, it’s form of like a donut association of the eggs, and the eggs are organized in normally three ranges. So that they’re type of eggs on prime of eggs on prime of eggs in a donut-like ring association with the adults ft are throughout the heart after which the animal’s form of draped on prime of the higher degree of the eggs. So actually these decrease degree eggs, their one finish is form of uncovered within the donut gap however for probably the most half they’re buried in sediment. They’re not likely absolutely uncovered. I imply are you able to think about, I imply I suppose you may argue that that’s simply how they received buried however I can’t think about that you can protect them in any other case. mainly should you’re stacking cylinders on prime of cylinders to me they must be buried when the animal’s sitting on them. I can’t think about that you can prepare Coke cans, , in a three-leveled association with out sediment packing it in. So I believe they’re pretty buried, and the porosity of the eggs is in step with that interpretation too.
So the precise quantity of contact between the adults and a person egg shouldn’t be very a lot actually.
Garret: However Troodon had a barely completely different nest?
Dr. Dave Varricchio: Yeah Troodon, like Oviraptor, has these elongated eggs however Troodon eggs are planted extra upright within the floor. And they also’re form of extra compact of their association, and so the higher components are all uncovered however in a decent configuration the place the stomach of the animal presumably might type of relaxation on prime of all these egg tops all on the similar time.
Sabrina: Fascinating.
Dr. Dave Varricchio: After which a few of that will get carried over into among the […] (00:19:57) birds, so among the birds of the Mesozoic have additionally upright preparations of their eggs.
Sabrina: I ponder, I used to be simply fascinated about just like the thickness of the eggshell and the way cautious you would need to be and the way a lot weight you can put onto them.
Dr. Dave Varricchio: Yeah Troodon eggs usually are not notably thick. It’s a few millimeter. However I imply Troodon‘s not, it’s not an enormous. , it’s 100 and twenty 5 kilos or one thing like that perhaps. So it’s not a extremely tremendous heavy animal. I imply it’s, , ostriches are 300 kilos and the emus and rheas, they’re type of within the Troodon range-ish.
Sabrina: That’s true. I suppose I’m considering if I sat on an egg…
Garret: A hen egg?
Sabrina: A hen egg, I might nonetheless simply break it.
Garret: Rooster eggs are so much thinner although.
Sabrina: Oh yeah.
Dr. Dave Varricchio: A whole lot of the load is on their legs even once they’re sitting, form of on their metatarsals, after which you may type of ease your physique mass onto the egg clutch.
Sabrina: Okay, yeah I see that is smart.
Garret: So it’s not likely like sitting on it, it’s similar to touching it.
Dr. Dave Varricchio: Yeah I believe the animal might sit down, however as its sitting down its weight is basically on its legs till, after which it could form of regulate how a lot weight is on the egg clutch. I don’t know, I type of really feel like oh I most likely might watch movies of nesting emus or one thing like that.
Sabrina: Yeah.
Garret: Yeah that might be fascinating. I don’t assume I’ve ever seen, apart from like a hen or a songbird or one thing a lot in regards to the subsequent. Like I don’t assume I’ve ever seen an ostrich nest. However they only lay, ostriches simply lay one egg at a time proper?
Dr. Dave Varricchio: Properly they’ve large clutches although however they lay one egg at a time, yeah. I imply all birds lay one egg at a time even when they’ve a giant clutch; they’re producing eggs one per day and ostrich normally takes three to 5 days between eggs.
Garret: So with burying the eggs you would need to have an open space after which form of cling round it for per week or two when you laid eggs earlier than you can rebury it.
Dr. Dave Varricchio: So yeah, I imply I suppose that might be the case if that was true. I don’t, , primitively animals lay eggs in mass like crocodilians and most reptiles and stuff, so I suppose I might presume that the majority dinosaurs could be laying their eggs in mass, so they might lay all their eggs on the similar time, and it’s solely whenever you get into maniraptorans the place we get this iterative laying. And that’s actually the place you get this large leap in egg measurement relative to grownup measurement. So like an oviraptor egg is about the identical measurement as a Maiasaura egg, however a Maiasaura is two tons, and Oviraptor is 200 kilos or one thing, or 150 kilos. So the egg is considerably bigger for the Oviraptor. So at maniraptoran’s the place we see numerous modifications in replica, and there’s modifications in egg form. The eggs turn into actually large relative to the grownup physique measurement, and that’s the place we begin to get this egg pairing which is form of how we inferred the iterative laying of eggs.
Garret: What’s egg pairing?
Dr. Dave Varricchio: So eggs in Oviraptor egg clutches are organized in pairs, and similar factor in Troodon egg clutches. It’s kinda laborious, you may’t at all times see it in each egg clutch however in good clutches you may see this egg pairing. So from that we proposed that Troodon and Oviraptor have been laying eggs, like mainly had reproductive tracts that have been functioning like a chook’s. They have been producing eggshell microstructure like a chook, they usually have been laying eggs two at a time. So one from every ovary and oviduct. , in order that they lay two eggs on someday and two eggs on a subsequent day. After which about ten years later they discovered an oviraptor that had two eggs inside, in order that was type of supportive proof that that was most likely the case.
Garret: Yeah that’s an excellent discover.
Dr. Dave Varricchio: So I suppose I don’t actually know if different dinosaurs outdoors of manoraptorans have been laying eggs one by one or two at a time. There’s no actual proof to argue that they have been, and so I believe the most secure assumption is that they have been most likely producing their eggs en masse. However I suppose I might say we don’t actually have robust proof in some way.
Garret: Yeah, I believe the burying factor appears fairly tough should you’re laying them one by one although.
Dr. Dave Varricchio: Proper. However Oviraptors presumably are constructing this advanced, and Troodon, constructing this bizarre advanced of eggs the place eggs are being laid two at a time. In order that’s form of a puzzle to consider as properly.
Sabrina: Yeah, a number of good puzzles.
Garret: So Sabrina and I have been simply within the Two Medication Dinosaur Middle, we did certainly one of their each day dig issues, and we went out to a nest and Sabrina discovered some eggshell fragments, they usually have been all very, very small. Is {that a} typical factor or do you ever discover a good intact egg that simply appears like an egg was buried after which was a rock?
Dr. Dave Varricchio: I might say within the Two Medication it’s fairly typical to seek out bits of eggshell. I imply eggshell’s pretty widespread within the formation, however to seek out good eggs is fairly unusual. More often than not they’re being laid in mudstones, and people mudstones have been compacted so the egg’s simply form of been flattened into, , a pancake of eggshell. However eggs laid in sandstones have extra potential. The sand is simply more durable to compact, so the eggs retain their three dimensional shames. A whole lot of the eggs from China are in coarser grained sediments, after which within the Two Medication numerous the Troodon eggs are laid in these sediments which have been infused with calcium carbonate in a while, and they also’ve been cemented fairly early on of their burial course of. So the eggs haven’t been compacted an excessive amount of, and people retain a reasonably good three dimensional form as properly.
Garret: Cool.
Dr. Dave Varricchio: I used to be most likely at that website truly this summer time.
Garret: Good.
Dr. Dave Varricchio: As a result of Dave Trexler, yeah I visited with Dave Trexler and we form of, he visited our website after which I went on the market with he and one other man out to his website.
Sabrina: Oh cool.
Garret: Yeah I noticed you probably did some work on the Two Medication, we simply interviewed Dave Trexler once we have been there too. He’s a cool man. You additionally did some work re-identifying an embryonic stay inside an egg, so is that one fairly properly preserved? And the way do you, what sort of situations do you want to get an embryo nonetheless contained in the egg?
Dr. Dave Varricchio: Ossification, so bone formation in embryos, truly takes place fairly late in growth. So you actually must get an egg that’s buried, , buried greater than its speculated to be fairly late in its historical past. So I really feel prefer it’s nearly shocking that we don’t have extra embryos although, so I don’t know if there’s one thing in regards to the chemistry of the rotting of the interior components of the egg that helps to interrupt down bone. I’m form of shocked that we don’t have extra embryos. However we don’t have very many.
Garret: Yeah as a result of to me it looks as if should you had an egg and the egg was preserved properly that no matter was within the egg could be preserved properly, however I suppose such as you say perhaps it’s too acidic or one thing or different and that makes the bones not stick, though if it was acidic then the egg most likely wouldn’t be there both.
Dr. Dave Varricchio: Yeah I don’t actually know the way that inside surroundings works, however you may assume although if the egg, if it takes 100 days for the egg to develop, if it dies within the first 75 days you’re not gonna see an embryo as a result of it’s not gonna have an ossified skeleton. SO it’s actually that final quarter of growth that you simply would possibly, , see the bones.
Garret: Okay.
Dr. Dave Varricchio: So it actually form of needs to be a late stage embryo earlier than you see good bones, so you actually form of, it’s a reasonably slim window in that growth. However you’d assume for the, just like the hundreds of eggs that come out of China that we’d have extra embryos.
Sabrina: That’s true.
Dr. Dave Varricchio: However perhaps it’s, should you get that far alongside the percentages of you surviving are higher than should you don’t if that is smart. Like should you’re that near hatching that there’s a excessive chance that you simply’re going to make all of it the way in which moderately than die ten days wanting hatching.
Garret: Yeah it’s most likely not equal percentages of no matter life expectancy I suppose you’d name it.
Dr. Dave Varricchio: Yeah I don’t know the way that works. I don’t know, there’s most likely, perhaps you may get numbers from trendy animals, I don’t know, that would supply some perception there I don’t know.
Garret: Probably a harder query: I used to be looking for what the most important dinosaur egg is and I discovered many sources saying there are tyrannosaur eggs which might be mainly big spheres, after which I discovered different sources saying there’s an oviraptorosaur in China that has a very completely different formed egg that’s very lengthy and thin, such as you have been saying Coke can sort form, but additionally very large. What do you assume the most important dinosaur egg could be from?
Dr. Dave Varricchio: Yeah I believe the 2 largest ones are the Hypacrosaurus eggs from Southern Alberta and Northern Montana which might be large, spherical eggs. They’re type of soccer ball in dimensions. A number of the doable sauropod eggs from South America may be that measurement, however I don’t assume they’re fairly that large. I believe they’re a bit smaller. After which the opposite one are yeah these big oviraptor eggs. The identify for the egg is macro-elongitoellisis. And a few of them are fairly lengthy, are 50 centimeters lengthy. They’re form of like large zucchini shapes, they’re lengthy and thin, however their quantity is form of comparable with the hypacrosaurs. I believe they’re each up round 4 liters, perhaps 4 and a half liters in quantity.
Sabrina: Wow.
Garret: Yeah that’s a giant egg.
Sabrina: It’s.
Dr. Dave Varricchio: Yeah. it’s nonetheless not as large as just like the elephant chook.
Garret: Wow, particularly contemplating elephant birds themselves weren’t even near a sauropod.
Dr. Dave Varricchio: Yeah.
Sabrina: Yeah.
Garret: After which do we all know what, so we’ve the identify for the egg however we’re not likely positive which oviraptor it got here from?
Dr. Dave Varricchio: The massive ones? , yeah I imply they match in microstructure and ornamentation and form different smaller eggs which might be related to oviraptors, and there’s a paper popping out, Darla Zolonitski is writing a paper I believe with Phil Currie describing one of many embryos from a few of these large, the makrolon telithis eggs. However I don’t know if it’s, I don’t know if there’s an enormous oviraptor from that formation that’s been named. I imply there’s mainly solely been one big oviraptor that’s been named. However these large eggs, there’s large eggs which might be from Korea, from Mongolia, from China and from Montana as properly. Idaho and Montana. We discover them in additional locations than we discover big oviraptor skeletal stays, so presumably there’s big oviraptors operating round laying these eggs however we simply don’t know extra about who it’s that’s laid these eggs.
Sabrina: That’s actually cool to consider.
Garret: Yeah. That appears unusual that there could be eggs however not skeletal stays.
Dr. Dave Varricchio: Yeah I imply it’s form of fascinating whenever you have a look at the egg, or it’s typically an eggshell document it typically doesn’t match the skeletal document. I imply that’s form of the issue in misidentification proper, that folks went to the Flaming Cliffs in Mongolia they usually discovered , they discovered 101 Protoceratops from tiny little animals to large full adults, they usually discovered all these eggs, so they only type of assumed properly there’s a number of eggs and there’s a number of Protoceratops, they need to go collectively. Proper? And that’s why they referred to as the primary Oviraptor that they discovered on prime of eggs that they, , they name it the egg stealer, however… So the numbers of eggs don’t usually match the numbers within the skeletons. So these formations that we’ve been working in jap Idaho and southern Montana, that’s the place we discover Oryctodromeus, so Oryctodromeus is the commonest dinosaur that we discover. After which the second most considerable stuff that we discover is eggshell and most of it’s this makrolon telithis, these big eggs. However we haven’t discovered one bone but for an enormous oviraptor, though there are some big oviraptor bones that individuals are form of engaged on in Utah from comparable age stuff.
Sabrina: Cool.
Dr. Dave Varricchio: So I had one pupil, that’s the coed that was, Jade Simon, she was engaged on the makrolon telithis eggs from these formations and he or she at all times form of joked that Oryctodromeus would possibly turn into just like the dinosaur kiwi. Like these eggs may be coming from, she, that was all tongue in cheek, she doesn’t imply that significantly, however…
Sabrina: Certain.
Dr. Dave Varricchio: However given should you took type of like what the document seemed like at face worth, we mentioned wow we received a number of these small little dinosaurs, we received a number of these eggs and form of like oh, , so it should be laying these big eggs. Anyway.
Garret: That’s humorous.
Sabrina: Properly thanks a lot for taking the time and talking with us at the moment.
Dr. Dave Varricchio: Yeah, thanks to your curiosity.
Sabrina: Simply needed to say thanks once more to Dr. Dave. We had a extremely nice discuss, and we at all times love speaking to paleontologists so it was good to listen to extra about his work.
Garret: Yeah and clear up among the issues that we didn’t learn about or weren’t positive about too. It was enjoyable. I particularly favored the concept of dinosaurs presumably giving stay delivery.
Sabrina: Yeah.
Garret: And it’d be enjoyable to see that someplace alongside the way in which.
Sabrina: It will, positively. So thanks once more.