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DrScottHartman β Postosuchus big and small
Published: 2018-06-15 20:13:38 +0000 UTC; Views: 18840; Favourites: 476; Downloads: 0
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Description
For such an iconic Triassic archosaur, Postosuchus has proven lots of trouble when it comes to restoring what it looked like and how it got around. Getting the proportions right isn't a trivial matter, as none of the remains are so completely preserved/prepped/described that they can stand in for an entire skeleton. Simple cross-scaling of the specimens isn't possible, as they are of different sizes and exhibit allometric scaling (more on that in a sec).With a bit of care I've managed to pull together a reasonable composite based on (and scaled to the size of) the type specimen,Β TTU-P 9000. One of the larger sticking points (in part related to getting the proportions correct) has been if and to what degree Postosuchus was bipedal. While the forelimbs are robust for their size, recent work has noted that the forelimbs are substantially shorter than the hind limbs, which at least in the type specimen I heartily agree with.
One thing that is interesting, however, is that the smaller paratype specimenΒ TTU-P 9002 has different limb proportions - the forelimbs are quite a bit longer relative to the hind legs, and in fact are nearly as long as in the substantially larger type specimen. I've scaled down the skull and axial skeleton to match the limbs of 9002 in the smaller skeletal above. It's tempting to infer that the young of Postosuchus were quadrupeds (or at least were _more_ quadrupedal), and as they grew Postosuchus spend more time on its hind legs alone.
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Comments: 70
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Are you planing to draw more rauisuchians ?
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Oh no the people legs
I don't know much about paleontology (at least comparatively to the rest of the commenters here) but having previously only been familiar with the former quad look thanks to a model I own, the memester in me is now sorely tempted to make a "birds with arms"-esque version of this with photorealistic human legs attached hfgjfgt
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Wasn't there a new skull of this fella discovered? Or am I misremembering something
Also, the skull of this fella really reminds me of Tyrannosaur skulls for some reason, mainly cause of the shape of the orbits, and the nose, as well as the teeth.
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You are correct, there are two specimens with good skull material. FWIW the skulls reminded Chatterjee of tyrannosaurs as well, in fact he proposed that tyrannosaurs might have evolved from these guys rather than other theropods. For a lot of reasons this never real caught on, but I agree with you (and him) that they do have a superficial resemblance, at least in side view.
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wait he really thought Tyrannosaurids evolved from these guys? WHEEZE
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Chatterjee seemed to really want to tie various derived theropod groups back to Triassic origins - maybe as part of his world view that Protoavis was an early bird, but phylogenetics kept placing the origin of birds higher up in the theropod tree?Β
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do you think we should tell him protoavis is just a chimaera.
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Hopefully by now he knows?
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hello Mr. Scott, I just created an account on this page, I've been seeing your skeletons for a while, until a few weeks ago I thought he was dead (I was wrong) has interesting projects, if you can suggest ideas for new skeletons these are my proposals : saurolophus angustirostris, saurolophus osborni, sinosauropteryx prima, corythosaurus casuarius, jinguofortis perplexus, xiaotingia zhengi, eosinopteryx brevipenna, serikornis sungei, changyuraptor yangi, shenzhousaurus orientalis, ichthyornis dispar, hesperornis regalis, titanis walleri, gastornis gigantea, dromornis stirtoni, genyornis newtoni, incisivosaurus gauthieri, avimimus portentosus, citipati osmolskae (the normal, not the sp) beipiaosaurus inexpectus, linheraptor exquisitus, shanweiniao cooperum, archaeorhynchus spathula, ningyuansaurus wangi or zhenyuanlong suni.
All these taxa have never been properly restored despite the good material with which they count, saurolophus angustirostris is known for at least 15 specimens, changyuraptor is known for a beautifully preserved full skeleton and most enantiornithes are never restored. You would be the first
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The good news is that some of these are done (but still under embargo) while others are in-progress. The bad news is that I am teaching a new course this semester which is an enormous time sink, and I'm also trying to finish up my dissertation, so there probably won't be very quick progress (well...until a chunk of skeletals come off of embargo this summer, then I guess you'll get to see some action).
Cheers!
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It's good to know, take your time and good luck with your work
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Would this creature have had aΒ M. pterygoideus anterior that extended into the antorbital fenestra, or at least some sort of jaw-closing muscle? What about other archosaurs (like dinosaurs)? There used to be some reconstructions of carnivorous dinosaurs with an antorbital fenestra filled entirely with that muscle (though to be fair, they still persist), but clearly they're not accurate anymore (Lawrence Witmer told me that no one argues for that anymore); that would have been filled in largely with air sinuses. But would there still have been a jaw closing muscle in there, even if it didn't completely take up the space in the fenestra?
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Really like it tbh, might be useful for pivot prehistoric animators that can make a Postosuchus stk. Still wondering, do you take suggestions for people that want a good skeletal of the creature they suggest to you?
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Wait, I am a pivot prehistoric animator too!!!! 
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I always read suggestions, but I rarely have a chance to take them. Almost all of my work is commissioned, and when it's not it's because I need it for research or publication.
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Did crocs mimic theropods or theropods did mimic triassic "crocs" (and bear in mind i'm using the term "croc" in the broadest way possible)?
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Or did some crocs mimic other bipedal crocs??
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DUN DUN DUUUUN
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It's always exciting to see new developments in skeletal reconstructions; I grew up watching Walking with Dinosaurs, so Postosuchus holds a pretty special place in my heart.
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Back when that came out I thought they'd made a good decision with making it quadrupedal. Ah well, live and learn!
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Could you possibly do a skeletal for Fasolasuchus?
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I'd probably have to do Saurosuchus first, as the description of the type material leaves something to be desired in terms of making a skeletal reconstruction. There's an odd chance I may get to do Saurosuchus later this year, so if you see that posted ask again.
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Those weeny hands, it's like a prehistoric Trump.
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i knew he was a crocodile
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Trump is prehistoric.
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A crocodile rocking the large theropod look before any large theropod lived, and, to top it off, also had what appears to be humanlike feet... Can't help but be awed.
In any case, what do we know about posture in the whole Rauisuchidae/Prestosuchidae grade? Poposauroids seem to be bipedal, and Postosuchus also seems to be an obligate biped, but animals such as Saurosuchus are commonly restored as quadrupedal, and I'm wondering how well supported is said choice.
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To be fair to theropods, Herrerasaurus is older and the "Frenguellisaurus" specimen is bigger than TTU-P 9000.Β
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Saurosuchus and Batrachotomus both seem securely quadrupedal. Also, not all poposaurids were bipedal, so by my count bipedalism may have evolved three separate times in crurotarsans in the Late Triassic.
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The gate reminds me of a pangolin a little bit, I can easily imagine it moving around like one, occasionally bunting the ground with its forelimbs.
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The paratype I meant to say
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That makes sense to me.
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Interesting - you'd think the smaller, lighter specimen would be the one that is a biped.
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While that sounds intuitive, a transition from quadrupedal to bipedal as they grow has also been inferred for some prosauropods. Maybe they aren't coordinated enough as youngin's?
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Interesting to see this guy walking on two. I recall first seeing an older version in BBC's Walking With Dinosaurs series.Β
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Yup, it's become entrenched as the view most people have of the animal (well, the people who know what Postosuchus is).
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Is it clear now that Postosuchus was bipedal and not quadrupedal? Or is it still uncertain?
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Thanks for the answers!
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In the larger specimen it seems that bipedalism must have been the norm, at least when it was going anywhere. We don't have anything like a complete ontogenetic series, but given the proportions of the smaller specimen it seems plausible that Postosuchus could have been been born quadrupedal and shifter to an ever-more bipedal stance as it grew and its limb proportions changed.
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The morphology of the manus, as well as the relative length of the arm to the leg makes quadrupedality extremely implausible, at least in the larger specimen.
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This was on the front page!
I've been seeing more and more paleontology pieces on the front page recently. Jurassic World: Fallen Kingdom hype, perhaps?
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Possibly? Anyhow, that's very cool!
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That beautiful creature must of been the equivalent of the modern African lion.
I'll bet that it traveled in prides or packs, as today's carnivores do.
Or, maybe, it was solitary, like the Asian tigers.Β
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So far the evidence is equivable, but hey, that means both pack and solitary lifestyles are still plausible!
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First Spinosaurus is back to being a semi-quadruped(which it is the only theropod whose a quadruped), and nowadays Postosuchus being a biped.
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Spinosaurus is short-legged but there is no reason to assume it was a quadruped.
And since most of its life was spent submerged, the argument is moot regardless.
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Thats the name of the game though. Its an ever learning experience as they dig up more and better preserved fossils. You get things wrong and then learn and keep perfecting it. Its not like other studies where things are easier to figure out. I love it when they figure out more about how things could have been.Β
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Man, this thing is way more weirder and interesting than I first thought.
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