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EWilloughby — Utahraptor ostrommaysorum
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Published: 2011-06-05 06:45:41 +0000 UTC; Views: 12597; Favourites: 285; Downloads: 363
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Reconstruction of Utahraptor ostrommaysorum intended for the Wikipedia article on the animal. *shartman 's skeletal used as reference.Download for larger version.
[Edit] Improved wrist folding, added tailfan.
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Comments: 103
Besides being the overall best Utahraptor life reconstruction on DA, this deviation stands out for another reason: It & everything in your gallery after it is WAY better than everything in your gallery b-4 it. What I'm wondering is how did you get so much better in such a short amount of time?
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Thanks, I appreciate that. Honestly not sure how I got better - I guess part of it is developing a new technique for drawing the texture of dromaeosaurid body feathers, which I developed around the time of this Utahraptor.
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"hanks, I appreciate that."
You're welcome.
"Honestly not sure how I got better"
Admit it, you're just saying that b/c you don't want anyone else to get as good as you (I kid of course 
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Beautiful reconstruction here. The feather texture is so well done and very realistic. I can imagine this as an actual animal rather than something fantasy as a lot of people's 'reconstructions' look.
You've used the skeleton reference to very good effect. Very nice.
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Thank you very much! It means a lot to know that I'm succeeding at making my paleoart look like an actual animal rather than a stiff (but perhaps still anatomically accurate) robot - it's not an easy thing to do.
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It is so beautiful!
I just love these details, feathers, fur. Anatomy is great too - you're really good at it. Fantastic legs and head. It's face is so cute too.
Beautiful, soft shading, just perfect for this style. :3
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Thank you very much, I appreciate that.
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WOW... This is awesome... Not only is the art brilliant, but I'm really glad you didn't feather it to sparsely because it is a larger species, as I believe that most raptors would have had an almost uniform pattern to their feathers. I think this is probably the BEST and most accurate Utahraptor out there. Well done.
Sorry if I come of as being a bit eccentric, I'm just a massive dromaeosaur fan.
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Thank you very much! I'm glad that some people appreciate the feathering. You'd be surprised (or maybe you wouldn't be) at how often I have to argue with people who are certain that feathering on larger dromaeosaurs would cause an overheating problem. Even though the available data on this indicates otherwise (feathers are insulators, not heat-specific, they can trap cool air too! And anyway, no one doubts that large extinct birds like giant moas were feathered, and giant moas were not that much smaller than large dromaeosaurs), I think the relevant thing is that bracketing must trump purported, unproven conclusions about lifestyle and non-fossilized morphology. So, I've reconstructed this Utahraptor as accurately as possible considering what we currently know about dromaeosaur phylogenetics. If one day a discovery is made that specifically indicates larger dromaeosaurs lost their feathers secondarily, then I'd revise my conclusions.
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Thanks! The feather style was loosely modeled after a kiwi (body feathers) and ostrich (tail and wings).
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Last time I checked there is no evidence that Utahraptor, and several other large Dromaeosaurids had feathers. My personal theory is that the larger members did not have feathers, and therefore should be reclassified.
Personal opinions on feathers aside this is very VERY well done and you are one of my favorite artists that does dinosaurs. 
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Thank you very much for your compliments on my work, that means a lot.
I'll have to disagree with you about the "no evidence" thing. True, there have never been larger dromaeosaur fossils found with feather imprints. This is because the formations larger dromaeosaurs tend to be found in - the Cedar Mountain formation and the Cloverly formation, for instance - do not have conditions suited to the fossilization of integument. You say there have been no larger dromaeosaurid fossils found with feathers, but there have also been no larger dromaeosaurid fossils found with scales.
But lack of physical evidence does not mean lack of evidence in general. The evidence here comes from phylogenetic bracketing , which is a powerful tool for predicting features of more derived clades based on the presence or absence of features in a more basal form. The Utahraptor article at Wikipedia explains this succinctly:
"Although feathers have never been found in association with Utahraptor, there is strong phylogenetic evidence suggesting that all dromaeosaurids possessed them. This evidence comes from phylogenetic bracketing, which allows paleontologists to infer traits that exist in a clade based on the existence of that trait in a more basal form. The genus Microraptor is one of the oldest known dromaeosaurids, and is phylogenetically more primitive than Utahraptor. Since Microraptor possessed feathers, it is reasonable to assume that this trait was present in all of Dromaeosauridae. Feathers were very unlikely to have evolved more than once in dromaeosaurs, so assuming that Utahraptor lacked feathers would require positive evidence that it did not have them. So far, there is nothing to suggest that feathers were lost in larger, more derived species of dromaeosaurs."
In paleontology, it's typically frowned upon to make assumptions about an animal's morphology that takes into account behavioral or adaptive factors but disregards phylogeny. Aside from that, though, there is even so no evidence that feathers would have been a detriment to a larger animal. Hair is a poor analogy (as in elephants and rhinos, which are indeed mostly hairless) because animal hair is strictly an adaptation for warmth. Feathers are much more complex, and act as very effective insulators: they retain coolness as well as heat, like a Thermos. This allows birds to regulate their body temperatures much better than if they were covered in a similar amount of hair. This submission [link] explains this idea in more detail.
It's worth pointing out that in the professional paleontological community, the idea that larger dromaeosaurs lost feathers as a function of size is not supported by a very substantial body of scientists. The importance of phylogenetics and parsimony bracketing is too important in the evolutionary sciences.
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See, someone I was talking with a while ago used the "feathers for warmth" argument which didn't make sense to me since these where not feathers that we know of today, and the cretaceous was generally warm and humid. But since you pointed out the ability to cool, it suddenly becomes a bit more for me to think about.
I assumed protofeathers were strictly for flight (or gliding), therefore rendering them useless in a large dinosaur.
I did the math a while ago, and something like 13 out of the 32 or so species in the dromeaosaurid family showed no evidence of feathers, all of them (if I recall) where larger in size. This made me think that perhaps they should not belong in that family at all, since one of the requirements is that they had protofeathers.
And I wouldn't need strictly feather imprints as evidence, quill knobs would work too.
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Additionally, I should emphasize that this purported 13-out-of-32-didn't-have-feathers idea would not be a reason to split a clade by any stretch of the imagination. Dromaeosaurs share a billion other synapomorphies that place them together.
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Very true, but a big part of being a dromaeosaur is having protofeathers. I think, at least, they should be classified as a sub-family.
I can prove my point with that logic also. You're using lack of evidence as evidence of protofeathers, so I can turn around and use the argument you made about the conditions being unfavorable for preserving feathers and saying the conditions were unfavorable for preserving scales.
I agree with a lot of what you're saying though. It's just that the evolution of feathers is just a big mystery (to me at least lol) and difficult to pint point exactly why they showed up in the first place. Why would an dinosaur evolve protofeathers as a form of display and not spikes, frills, or just plain old fancy colors? I don't think that's the reason. The only reason that makes sense to me is the theromregulation suggestion. Which, thinking about it more, weakens my argument that they didn't have any feathers. I'm still not convinced, but this does give me something to think about.
Also, is it just me or is phylogenetic bracketing just a fancy word for educated guesses?
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It's just you.
Phylogenetic bracketing, and how it relates to the concept of parsimony (and more generally the importance of parsimony in science, and how we can quantify parsimony), is an extremely important facet of evolutionary biology, and the modern state of evolutionary theory would not exist without it.
I definitely suggest reading up on this topic if you're interested, there is a wealth of information out there.
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I was actually going to ask you if you knew of any books dealing with it, especially things relating to feathered dinosaurs. I'd like to read up.
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I spent a while perusing my various books on feathered dinosaurs trying to decide which one I think is best to recommend. I ultimately decided on Feathered Dragons , edited by Philip Currie and others, with contributions by many esteemed paleontologists. This book explains the evolution of feathered dinosaurs, of flight, and of feathers in exquisite depth, but without going into unnecessary technical detail. It's from 2004, so it's missing some of the more recent information on Anchiornis, Microraptor biplane configuration, etc. Nevertheless I think it is an excellent introduction to feathered dinosaur evolution and I highly recommend it.
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Thank you so much! I will definitely be purchasing that book. This whole conversation has given me a lot to think about.
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Protofeathers definitely didn't evolve for flight or gliding. Many reasons for this: in order for protofeathers to have evolved "for" flight, there would have needed to be an evolutionary precursor that had wings but not flight-capable feathers, and bird wings without feathers would be useless for flight. Evolution is not a directed process, it doesn't know what the end result will be, so a fully-feathered wing could not sprout of nowhere capable of flight. Feathers clearly evolved for some other reason besides flight, and were later modified for flight. This is also the consensus among paleontologists at this time.
The strongest obvious evidence of this is Sinosauropteryx , the first known feathered dinosaur. Sinosauropteryx was a very small basal coelurosaurian with relatively tiny arms. [link] Clearly it would not be able to fly, yet its fossil shows a beautifully preserved coat of down-like feathers. Nowadays most people believe that feathers first evolved in archosaurs as a means of either thermoregulation, or display.
The 13 out of 32 thing is completely meaningless. Every single dromaeosaur that has been found with feather imprints was (obviously) found in a formation that had conditions favorable to preserving imprints. If 13 out of 32 dromaeosaurids show no evidence of feathers, all that really means is that 13 out of 32 dromaeosaurs happened to fossilize in a formation that isn't conducive to the preservation of imprints. If this was relevant, we would have found scale imprints on at least one of those 32 dromaeosaurs. The lack of quill knobs is unfortunate, but there are two explanations for that: quill knobs are only present for larger feathers, and it's possible that Velociraptor was the largest a dromaeosaur was able to get and have arm feathers large enough for quill knobs to be evident. More likely, though, is simply that the the known parts of larger dromaeosaurs would make interpreting quill knobs difficult. Utahraptor, for instance, is only known from skull fragments, claws, a couple vertebrae and a leg bone, so there would be no quill knobs on any of these parts anyway. Deinonychus and Achillobator fossils are incomplete and in many cases crushed or distorted. As the Velociraptor quill knob study is still fairly new, I am hoping that with time, more sophisticated methods of quill knob determination will be used on existing dromaeosaur fossils, if that's possible given their preservation.
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That, and not even all modern birds have quill knobs to begin with.
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I did not know that, thanks for pointing that out.
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Indeed, is there anyone in the scientific community who actually doubts that any dromie had feathers? Even the BAND now confess that deinonychosaurs did have feathers; they just think that "raptors" are "birds and not dinosaurs" now.
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Not that I'm aware of! Paleontology: if your views are more extreme than Feduccia's, they probably aren't correct.
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Awesome work! Love the detail on the feathers
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You already know my opinion on this but here it goes: A-W-E-S-O-M-E!
The only thing missing if I have to be totally honest with you is the right arm. As far as I can tell from where I'm looking it should be visible. But it's a testament to the work you put into this that it took this long for someone to notice that
I've been without awarding favourites for so long I have to ask is the little popup "Don't forget to leave a comment" a subscriber perk?
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Thank you very much! And as for the right arm: haha. The original position of the left arm was such that the right arm would not have been visible, but then Joxer pointed out that it was probably too tightly folded , so I changed it... after changing it, I didn't even think about the fact that the other one should be visible now. Thank you for pointing that out.
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You're very welcome
Yeah, I thought as much seeing your work-in-progress shots elsewhere. Boy, do I know that pain in the hand drawings are
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An excellent depiction. One of the best I've seen in fact.
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Thank you! I went to a lot of effort to make it as accurate as I was able to.
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You're welcome. It certainly paid off.
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This looks really fantastic. I generally agree that dromaeosaurs would probably be more drab than usually depicted. How likely would a very deep bluish-gray color be for one? I'm curious since I have an indigo Utahraptor character, and a grey Deinonychus. My characters aren't really supposed to be realistic, but I'm curious, anyway. x3
I love how the feathers have so much texture to them, and that you detailed the scales on the feet and snout, too. The ferns are a nice touch.
My only critique is, and this could just be me, but it looks like the eye is further forward than the surrounding feathers. I guess a better way to put it is, the eye looks like its in higher relief than the feathers. I think maybe if the glare was a smidge smaller, and there was detail right above the top of the eye (as on the bottom with the slight shadow/detail) it would look better. Again, this might just be how I'm seeing it though, and hopefully that makes sense.
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Thank you very much, Naz.
I totally see what you mean about the eye. It's subtle, but thank you for pointing it out. I changed it very slightly and reuploaded the image (also gave it a right arm as Dracontes mentioned!). The change is small, but let me know if you think it looks better if you don't mind.
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Yeah, I know that true blue is caused by reflection of light in air pockets in the feathers, right? Which would require flight feathers. Would an indigo color be caused by pigment, then, or also air pockets? Sorry for all of the questions. Feel free to point me to a website or wiki article if it explains it accurately.
I think the eye looks a lot better now! I think the right arm was a good addition too, because yeah, I think it would be visible from that angle. I'm very glad my critique could be helpful! 
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Yep, blue coloration in birds is caused by the refraction of light on the tiny air bubbles trapped in the barbules of feathers. Very few non-avian dinosaurs have feathers containing barbules - barbules are very characteristic of flight feathers. Microraptor has them, for instance, so theoretically a blue Microraptor would be perfectly acceptable (actually, there are some people who say that they've observed evidence of actual blue iridescence in Microraptor fossils). Indigo, as a gradient of blue, would probably require this structural conformation in the feathers in order to exist. To my knowledge, there are not any "true" indigo pigments in birds.
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When you say "true" indigo pigment, what do you mean, exactly?
Thanks for all the information though, its interesting. Does green also require a similar structure of the feathers, or is it reliant on pigments?
Even if the characters we've chosen to represent ourselves aren't realistic, it's still fun, and coloration aside, I try to draw Nazrindi as realistically as I can.
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By "true" I mean a pigment that is directly responsible for the color indigo. There may be combinations of different pigments that result in an indigo-like color. I don't think this is the case, but I don't know catagorically that it's not.
Green is a similar case. 99% of green coloration found in birds is a result of yellow pigments, generally caratenoids, in combination with blue structural coloration (air bubbles in barbules). So, all of the green you see in parrots, hummingbirds, ducks, birds of paradise, etc. are all structural blue + caratenoid yellow. However, green has one very notable exception. The one known true green pigment found in birds is called turacoverdin , a copper-based porphyrin. This is found chiefly in turacos, but may be found in other birds as well. Check out the article (I wrote the whole thing from scratch myself
I generally consider green in dromaeosaurs unrealistic also, though not quite as much so as blue. Evidence suggest turacoverdin may have evolved separately in at least two lineages of unrelated birds, so it may theoretically be possible that it (or something structurally similar) evolved in dromaeosaurs, too. However, I think this is fairly unlikely and I would not have chosen green markings for my character had I known about these issues years ago. Still, as you said, it's fun.
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I know that indigo buntings and indigobirds both have the color they're named after, but I don't know if it's due to a pigment, either. I can't find any information on it. 
You did a really good job writing that article. I thought it was very informative.
I wouldn't have chosen indigo for Nazrindi had I been thinking about this more carefully before, either. But oh well. 
I have one more question...what would be the most likely structure for Utahraptor and Deinonychus feathers? I've been looking on here: [link] And even though Dromaeosauridae isn't listed, they should be around the position Oviraptorosauria is. Does this mean that they would also have "4" and "6" style feathers? (Being multiple filaments along a central one, and pennaceous feathers with a vane of barbs, barbules, and a central rachis respectively.) I'm assuming the later type is the kind you've depicted on the Utahraptor's display feathers here.
Sorry for filling up your page with so many questions. I don't get the chance to talk with you much about this, so... x3
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Indigobirds and indigo buntings definitely do not have an indigo pigment, their coloration is due to the structural refraction of light on trapped air bubbles. As I said, I'm pretty sure there is no blue (or indigo) pigment in birds (even the blue-footed booby's feet are blue because of structural coloration, albeit a different type than in feathers, instead of pigments - can you believe it?).
Utahraptor and Deinonychus definitely would not have had stage 6 feathers, even in the display region, although they may look similar from a distance. The biggest difference is the barbules, which larger dromaeosaurs would not have had. There are several lines of evidence for this. First, as a modern analogue, consider the ostrich or any other ratite. I imagine that the display feathers in this Utahraptor illustration would be similar to the wing and tail feathers of an ostrich (I think that would be considered stage 4, or somewhere between 4 and 6, in the drawing you linked). Ostrich feathers have a central rachis and filaments with barbs growing from the rachis, but the filaments lack barbules. To the best of my knowledge, all extant flightless birds lack barbules. This explains the structure of the feathers of extant flightless birds. So, I imagine that larger dromaeosaurs would have had pennaceous feathers that simply lacked barbules. Extant birds show that barbules are lost very quickly by evolution when a lineage transitions from a flying to a flightless form.
Another theory I've heard tossed around about the reason for a lack of close-vaned, barbuled feathers in larger dromaeosaurs is the difficulty in maintaining such a feather. In order for barbules to be of any use to birds that use them to fly, they must be "zipped up" (the whole point of barbules is to interlock with one another, sort of like velcro - this "zipping up" of the feather forms it into a smooth, almost solid sheet which is very useful as an airfoil). That's why birds preen, and it may very well have to do with the loss of teeth, and evolution of a hard keratinous beak, which is universal among modern birds. Microraptor's feathers had barbules, as did the feathers of Archaeopteryx - both of which had teeth, yet still managed to preen them adequately enough for gliding or very simple flight. But it's very difficult to imagine a reason for an animal like Utahraptor to have barbules. (So, no, no air pockets either.)
I don't mind the questions at all! Feel free to ask anything and I'll do my best to answer.
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Yes, I can believe it, in regards to Booby's blue feet. 
It's incredibly sad that I don't know all of this already given that I'm a Biology major, huh?
I figured they probably wouldn't have had barbules on their feathers, since barbules are a requirement for flight feathers, and seeing as large dromaeosaurids most certainly couldn't fly, it would be evolutionarily costly to possess them. The preening issue makes perfect sense, I imagine they'd be spending far too much time preening to maintain them, and not only that, but their teeth would probably ruin the structure to some extent.
Would you agree with Wikipedia's stance that Oviraptorosauridae had stage 6 feathers, then? That seems incredibly unlikely, given that large dromaeosaurids also lost barbules. I wouldn't know where to find the original Xu et. al. paper though, so maybe they have an explanation for it that supports this idea.
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It's not sad at all. I assure you that absolutely none of this I learned in any biology class I've taken.
The stage 6 thing from Wikipedia is kind of misleading. Oviraptorids did not have barbules on their feathers, but they did have barbs on the filaments extending from the central rachis. There's no stage feather on that diagram that corresponds to a pennaceous feather that has a central rachis, filaments with barbs, but no barbules. This stage of feather certainly does exist and that's the kind of feather oviraptorids had. Oviraptorids did not have interlocking barbules.
These might explain it a little better: [link] [link] In these diagrams, stage 3 has two different substages, A and B. 3B is likely close to what oviraptorids had. Stage 4 and beyond are not found in animals that aren't doing at least a little flying or gliding.
I know the stages here are different than the ones at Wikipedia; I'm honestly not familiar with the stage division chart there. I hope I haven't managed to confuse you more than inform you with this stuff...
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Ferahgo, nice job on that turacoverdin article! Learned quite a bit just from perusing it, definitely need to read up more in depth on some of those sources. The galliform connection is very intriguing.
The problem I see with green dromaeosaurs is that both turaco pigment and the bright yellow carotenoids necessary for the yellow+blue=green mix requires a high degree of herbivory or even frugivory (though the Jacanas seem to maintain their coloration with insects). It wouldn't be impossible to see green pigmentation in the smaller, basal and partly omnivorous forms, but it would be very, very unlikely in things like Utahraptor, Deinonychus, etc.
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Thanks, I appreciate that.
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Yeah, I would think it slightly more likely (but still a leap given its rarity even in modern animals) that they'd go for the intestines and/or feces of their prey like the Egyptian vulture, to maintain a high carotenoid diet. At least feces could be gotten fairly easily without having to essentially be first to a kill.
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