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DrScottHartman — Centrosaurus apertus
#anatomy #ceratopsian #dinosaur #mesozoic #science #skeletal
Published: 2015-05-27 18:24:35 +0000 UTC; Views: 14090; Favourites: 200; Downloads: 0
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Description
Too busy for clever titles, but here's Centrosaurus, with the skull of ROM 767 (and the forelimb associated with it). Other elements based on miscellaneous Canadian centrosaur material.Related content
Comments: 56
It's been so long since I've seen Planet Dinosaur I had to look it up, but you're right, they're in Episode 3 ("Last Killers").
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I downloaded it through my iTunes so I can have it on my laptop! 
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Awesome one of my favourites! Basically anything from the Dinosaur Park formation...or any other fellow Canadians.
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You may be in luck then in the coming weeks.
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Wow! You're skeletal drawing looks great, so I could draw on for one day.
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A return to the Centro?
Ah, if only TARDISes were real.
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This one looks like a subadult to me (short nasal horn and parietal hooks smaller than normal).
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In some ceratopsians the horns can get shorter with old age, but in this case I'm pretty sure you are correct.
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Do you think you'll ever do the skulls of the other variations and "species/genus" of Centrosaurus? I also imagined this dinosaur as highly variable within the species similiar to some modern day animals like killer whales or humans. If it's not just that, then maybe it's like how zebras and leopards have distinct spots from each individual to the next, albeit with Centrosaurus it's their nasal/brow horns and the hornlets on the frill. Or of course they could be sub-species that are spread throughout the stratigraphic layers of the formation, but another likely hypothesis is that like some slugs and killer whales, they could have different "morph types" that depend on certain regions, even in the same close proximity (I recal some slugs that have different morphs within the same species and still live in the same proximity, but I forgot the species name so I can't recall the exact article).
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That would be a great project, but it's not currently on any of my lists.
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Okay, maybe some other time, so what are your other projects on the list if I may ask (or is it a suprise)?
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This is a great skeletal.It seems that the nasal horn is wider than I would have expected as well as the nasal cavity.Great work.
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Nice, and a "slightly alternative" skull, compared to a lot of repetition in many other restorations. It seems as if Centrosaurus would be frustratingly diverse back then, and it would be cool to get used to all the different variations of their skulls, so we can begin to imagine it as such. All those variations make it easyer to understand where all the different species come from as well.
It is also very unusual to imagine, compared to todays animals, where large animals of that size usually "rule" their environment, a species at the time. A European moose or bison have very few - if any rivals. Centrosaurus would be almost "surrounded" by other "clans" of all kinds of horns and genetic heritages, pockets here, groups there, all wandering and criss-crossing in a landscape that is more than big enough to render them all insignificant lil dots in the land 
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Thanks - the skull choice was related to the venue where the skeletal will be used. But I agree that there needs to be less-slavish adherence to using the same skull. That said, I'm not sure whether we're really going to see all this variation end up being responsible for false species (i.e. a population that is over-split) or if we're going to see a lot of these emerge as stratigraphically-tied morphs as the populations evolve. That's certainly what seems to be happening with Triceratops (whether you include "Torosaurus" or not), and the Montana folks have already made a preliminary presentations suggesting as similar pattern for earlier ceratopsians. In which case we might actually only get a couple of genera at once (e.g. a chasmosaurine and a centrosaurine...possibly with sexual morphs).
I'm not saying this for sure is correct, but it's good to be aware of it rather than embracing the dozens o' contemporary dino genera hypothesis uncritically.
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Oh, absolutely, I count that as well! It's variation upon variation, it's nature just throwing us everything it has, "you want horns? Here, horns for you!" and we're now struggling to figure out how to even name it!
I like that nature don't have a limit like that. I'm glad I'm not into invertebrates, for example, nature plays the big drum there "You like invertebrates *and* to make complete species-lists? Whooo!"
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I feel like such a large animal should have a much less crouched posture. It should be too heavy for its muscles to support without the help of vertical limbs to act as pillars. My impression was that that's part of why stegosaurs and hadrosaurs are now depicted with their hips way up in the air. As ornithischians, I feel like centrosaurs should probably be the same way.
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You may feel that way, but the limb morphology is very clear: they did not have upright, elephantine limbs. In fact straightening the knee past ~120 degrees would terribly hyperextend the knee just as it does in most dinosaurs (including hadrosaurs, by the way), meaning a horned dinosaur could only do this once at most (and presumably only when the ceratopsian mafia wanted to make a strong impression).
Within dinosaurs only sauropods and some derived stegosaurs do this, regardless of mass (though some have argued that nodosaurs sort of go halfway with the knee). Also, you should know that limb flexure in upright animals does not seem correlate with muscle effort in terms of holding up the body, instead it correlates with walking efficiency, where flex-limbed animals can be more athletic but aren't as efficient at walking, while straight-limbed tetrapods are the other way around. And again, this is not correlated with mass (hence humans with our straight knees are efficient at walking but not great runners, while Indricotherium retained flexed limbs like other rhinos despite out-massing the largest elephants).
I'm not saying mass plays no role - animals that are much larger than their predators have no reason to run and are probably more likely to be selected for walking efficiency over athleticism since the former is always valuable and the latter becomes less important, but remember that dinosaurs also were much larger predators, which may explain why larger ones retained flexed limbs most of the time.Submit Comment
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While you clearly know more than I do about dinosaur physiology, I have to disagree that limb flexure does not correlate to mass. There are of course exceptions like rhinos, but for the most part modern mammals' limb flexure decreases as size increases. Small mammals like rats have an extremely crouched posture so that each step has enough distance to provide the power to push off the ground. Large mammals like horses have a much more upright posture because flexion increases loading on bones and muscles that already have to support a lot of animal. This is why only the most powerfully-muscled Lipizzaners, Andalusians, and other European warhorses are capable of the levade, an air requiring the horse to crouch on its hind legs with the body at a 30-35° angle to the ground. Other horses simply don't have strong enough butt muscles to support their mass with flexed limbs. James Usherwood's paper "Constraints on muscle performance provide a novel explanation for the scaling of posture in terrestrial animals" provides an excellent explanation of what I'm talking about.
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Perhaps I should have said it doesn't correlate linearly with mass - e.g. just because elephants are graviportal doesn't imply that similarly-sized dinosaurs were. In fact with rhinos, ceratopsians, and hadrosaurs all having flexed limbs there may be as many species of rhino-elephant+ sized animals that have existed with flexed limbs than there are with graviportal limbs. I don't doubt the general idea of muscle volume scaling from the Underwood paper, but remember that "athleticism" doesn't always mean "running". Also, the overall correlation is at least partially confounded by ecomorph limitations (e.g. small arboreal or fossorial animals may have crouched limbs for reasons not related to size, but large animals are barred from those niches for reasons not tied to muscle scaling). I suspect that we will get much better fits when we start to break up these groups into ecomorphs.
As for the horse example, I don't doubt your explanation of which horses can do it, but the levade is an unnatural position that requires extra limb-retractor muscles to perform, so I don't see how it relates to the size-determinant issue you raised for limb posture - I could make similar examples of attainable poses between myself and gymnasts (e.g. the iron cross on the rings) that work exactly the same way despite the order of magnitude size difference between us and horses.
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Regarding the horses, my point was that only exceptional individuals can attain a position that is normal and requires little effort in many smaller animals, such as raccoons. As to the rest of it, I concede the argument. I still think it looks awkward, but I have a BA's knowledge of something you've clearly devoted much more research to, so I'm going to quit before I'm tempted to try and pull supporting data out of thin air.
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I can appreciate strange new dinosaurs... when they're real. But that indominus rex atrocity? *long, drawn-out sigh of disappointment*
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Oh I don't know - none of the other dinosaurs in Jurassic World are accurate, making it silly to put the names of real dinosaurs on them; at least Indominus rex has an excuse since it's a genetic chimera.
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Aren't all JP dinosaurs though?
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Supposedly their new dinosaurs aren't (there's a fun Ingen promo video floating around on this). I assume it's to help make I. rex seem more egregious (what, they purposely made a GMO dino, fwha???), but the downside is they actually removed the excuse for why their dinosaurs suck.
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They do note in JW, in a conversation between Wu and Masrani (sp?), that NONE of the dinosaurs are real; they're all genetic hybrids built more to be "cool" than "accurate." Which pretty much explains why none of the coelurosaurs (which make up at least half of the therapods featured in the series) have feathers. The Indominus is even more of a chimera than the other dinosaurs - though you really can't tell, considering it looks like a generic carnosaur with spikes.
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Im gonna keep the Frog gaps in my mind, Its kind-of a staple.
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Yeah, but if they get to just make it up, at least be creative. This looks just like an Allosaurus with superpowers, nothing interesting about it.
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It's also an albino? Yeah, I agree, but really at this point I just hope the movie doesn't suck.
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Not anytime soon, it's not on my commissions list. I really would like to do it though - something seems fishy with the reconstruction (and not just that they ripped off Jaime Headden).
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no matter when you get around it, I'd love to see your take on it.
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Wow!
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You'll see quite a few new ones in the coming weeks - I have work to get done.
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Is one of them, maybe, a Yutyrannus
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I'm still excited for the new skeletals, whatever they are
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I don't know - the downward facing hooklets are sort of strange, and I suppose it's subjective whether you think large brow horns are more or less vanilla (they's basal, after all) but yeah, it's pretty vanilla compared to the newfangled Kosmoceratopses and Diabloceratopses of the world.
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that's what I had in mind.
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You kids and your fancy swiss-army ceratopsians!
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I suppose you work on lot of specimen doing this skeletal, so the is right for the question:
What do you think on craniofacial difference in Centrosaurus (expeccially the horn curvature)?
And also is the parietal ornamentazion the only difference between the 2 Centrosaurus species?
Thank you
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Honestly I would hesitate to make any pronouncements on the "species" of any centrosaurine. "C. nasicornis" has also been considered to be a species of Monoclonius and to be a female specimen of Styracosaurus. I'll say that there are definitely differences between it and C. apertus, but what that means probably requires more specimens (right now we have precious little grasp on expected variability and stratigraphic range for these species).
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Not to be confused with Kentrosaurus.
Seriously, every time I look up one or the other, the source mentions the similarity of the names of these two dinosaurs.
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