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EWilloughby's avatar

Utahraptor ostrommaysorum

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Reconstruction of Utahraptor ostrommaysorum intended for the Wikipedia article on the animal. *shartman's skeletal used as reference.

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[Edit] Improved wrist folding, added tailfan.
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Xiphactinus's avatar
This is one of the best images of Utahraptor. I really like the pose and details of integument.
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?
EWilloughby's avatar
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.
"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 ;) )!
PeteriDish's avatar
elsarose's avatar
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.
EWilloughby's avatar
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. :)
Iagal's avatar
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. :D
Beautiful, soft shading, just perfect for this style. :3
EWilloughby's avatar
Thank you very much, I appreciate that. :)
Iagal's avatar
No problem. : D
Sketchy-raptor's avatar
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.
EWilloughby's avatar
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. :)
BondArt's avatar
This is gorgeous! Love the feather style!
EWilloughby's avatar
Thanks! The feather style was loosely modeled after a kiwi (body feathers) and ostrich (tail and wings). :D
Sgt-Nelson's avatar
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. :) Your detail work here is excellent, it's very easy to imagine what this may have felt like in real life.
EWilloughby's avatar
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.
Sgt-Nelson's avatar
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.
EWilloughby's avatar
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.
Sgt-Nelson's avatar
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?
EWilloughby's avatar
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. :)
Sgt-Nelson's avatar
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. :)
EWilloughby's avatar
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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EWilloughby's avatar
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.
Albertonykus's avatar
That, and not even all modern birds have quill knobs to begin with.
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