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yoult — *OUTDATED* Feathers of Deinonychosauria
Published: 2012-02-26 02:05:00 +0000 UTC; Views: 5743; Favourites: 66; Downloads: 66
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DO NOT FAVE! THIS IS OUTDATED AND INACCURATE!!!Because many people (me included) do their feather work on Dinosaurs particularly on Deinonychosauria and other Maniraptora wrong, I did a little research again and came up with this little t*torial, cheat sheet or how you want to call it.
I thought if this can help me not to forget how wings are constructed and feathers are connected, it could also help some fellow Deviants.
Hope you enjoy and I hope I didn't make an error in it. If so, please note!
Description:
figure 1
Shows the arm bones of a generic modern bird. The Scapula (shoulder blade) isn't showed here, because it's not important for the tutorial.
As you may notice, there are lines which come from the Digitus major (Digit II) and the Radius - these are the junctures of the Primaries respectively the Secundaries.
Note that the Humerus (upper arm) has no attached Secondaries, they are all on the lower arm while the Primaries are attached to the hand (more precisely Digit II).
figure 2
This is basically the same as figure 1 using an arm of a generic Deinonychosauria instead of a bird. The digits in here are more articulated, but that doesn't matter for the feathering. The Primaries are attached to Digit II and the Secondaries to the Radius. The Humerus plays no role.
figure 3
This shows how the feathers should lay on the wing of a modern bird. They are overlapping like roofing tiles and in every bird in the same direction.
The Alula are specialized thumb-feathers which are essential for the flying ability of modern birds.
Because of the overlap it may look like the Secondaries are on the Humerus as well, but that assumption is incorrect, all Secondaries are attached to the Radius.
The last three (sometimes more) Secondaries to the body are in many birdspecies changed into the so called Tertiaries/Scapulars - the purpose of them is to hide and protect the important primal feathers from dirt, wetness and damage, while they are also a good insulation for the bird.
The grey area in here is the body plumage, not a part of the wing-feathery.
figure 4
Same as figure 3 with a raptor instead a bird.
Note that there is no known Dinosaur which had Tertiares/Scaulpars, this is an adaption restricted to modern birds. Therefore they drawing is a little bit inaccurate - you have to imagine a little gap between the Secondaries and the body plumage.
Also Deinynochosaurs and all other nonavian Theropods lack real Alula. What is labeled here is the Alula are simply unadapted thumb-feathers, hence we should better call it "Pseudalula". Like in the previous figure, the Humerus looks kinda overlapped, but that has not the meand, that there are Secondaries connected, they are only on the Radius (you may notice this is a very important rule, because I repeat it so much).
figure 5
I'm really not sure here, if this is the correct execution of legwings. I used reference from some other Paleoartists and that was the outcome.
Because the upper leg is in all probability merged intot he body, it looks like the leg-wing ends at the end of the leg. This is not true as we see here, it only goes to the knee.
Upper leg and upper arm are no good for wings, please don't attach the Secondaries on them.
The thumb has on Maniraptora now flying function, real Alula or attaching the Primaries on it is wrong - don't do it.
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Comments: 27
This is great! I was not really sure on how to arrange the alula to non-avian winged dinosaurs and you just showed me how. Thank You!
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Non-avian Maniraptora are rather unlikely to have an Alula (at least we have no evidence for it). You would go better to not draw one on yours.
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Oaky. But, what about Microraptor? I am not exactly sure were, but I have heard that Microraptor probably had them. Do you think that is true?
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Here's a photo of the Microraptor gui holotype (the thumb-feathers are visible on the left arm).
In real-life it most likely looked like this and this .
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Thank you for taking the time to do all that! It is very much appreciated.
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There are some uncertainties left from my side. I need to recheck my sources before answering.
Note that the chart above is already outdated. A new one will come, but I'll answer you within the next days.
So far I can say, Microraptor had no Alula as known from modern Aves or the extinct Genera Protopteryx and Eoalulavis. Its appearance was quite similar, but more to go in the actual answering.
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I'm starting to think the feathers on my velociraptor suck.
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everything is a learning experience. practice!
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In addition, not all "Deinonychosaurians" have remiges (rachis, barbs and barbules), take Sinornithosaurus (NGMC 91 and IVPP 12811) for example, their wing feathers are similar to the semiplumes (rachis and barbs and no barbules) of modern birds. Since, these feathers lack barbules, it would be very unlikely for these feathers to form a closed pennaceous vane.
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Thank you very much for the critique, the tips and examples. I guess I've got some things wrong and shall learn more again.
I'll try to make a better tutorial (perhaps that time more precisely) sometimes.
For the Ulna-Radius-Thing I got somehow confused by Ferahgo-the-Assassin in the comments, she might have prescribed. First I got it right, but than I edited it dumb.
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Looking back at this, it seems to me that these animals could have feathers ranging from stage 2 to at least 4 as in this [link] , I wondered. This condition varies between species. For animals without integument preservation, there is not really a set rule for reconstruction of the kind of feather (stage 2-5, from something like the sinornithosaurus [link] to full pennaceous feathers found on microraptors) it should or shouldn't have.
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Remember Foth's paper though. It would seem that most (if not damn near all) feather impressions are actually making the feathers appear far simpler than they were in life. I'm not sure there is any reason to think that anything less than stage 3 was present anymore on Deinonychosaurs.
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I've only read the abstract and I don't have access to it (unless I paid for it). My comment is solely based on the sinornithosaurus paper, which does show quite clear feather impressions (like no barbules on the "arm" feathers) on the animal, on the other hand, the paper on "Dave" is also clear enough to see the vaned feathers (as mentioned before perhaps "Dave" might not be a sinornithosaurus). I don't know if I would change my opinion of these "arm" feathers on sinornithosaurus (IVPP V12811) even if I eventually purchase and read Foth's paper... because the photos from the sinornithosaurus papers aren't really that ill defined and the quality of these feathers are probably better preserved than "Dave's" IMO (somehow you can still make out the vaned feathers on Dave but not on IVPP V12811). If such specimen (IVPP V12811) didn't exist I may even agree with you on the topic. Maybe Foth's paper have some solid evidence in it (like a photo) to show otherwise, I probably have to catch up on my readings. I'm not saying it should be one way or another but I'm certain that there are variations between species.
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I can e-mail you the paper if you'd like. It does make an excellent case for 'single filament' feathers in dinosaurs (outside of EBFFs) being solely a preservation artifact.
I have no doubt that there was variation between species, definitely agree with you there. I just don't see any reason to think that filamentous 'stage one' feathers would exist at all in aviaremigia when there is really no evidence for it.
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Well, here is the [link] of the sinornithosaurus I'm talking about, I honestly don't think that is an artifact since its description is so specific in the article and the photos are not that bad either. Assuming there are vaned feathers, it is very unusual that none were identified (the primaries and secondaries would have been some of the last integuments to go, since they are embedded deeper than the other covert feathers), in the paper only two types of feathers were found but none of them indicate the present of barbules (or another word, none of these branched structures have interlocking elements to hold their shapes). I don't think lacking barbules is an indication of these being more primitive structures, these animals might just have redeveloped their feathers to be without barbules because perhaps they weren't using their wings to fly/glide anymore. Maybe they (sinornithosaurus) used their front quarters to help them catch preys. As to no evidence as you would say it from your comment, I'm not so sure since the photos from the paper are clear and I haven't seen someone trying to refute the paper yet. This is plainly based on observation rather than assumption or reasoning (These structures are just there, you can visibly see them. That's enough evidence for me). My email is boatperson@gmail.com, so please send me the paper. I hope your paper is based on solid evidence. To me just to say preservation bias when you can't find an expected feature is far weaker evidence than what has been presented so far from looking at the actual "decently" preserved impressions. So my evidence is pretty much to say... "just take look at the specimen photos (see above link)". Again maybe your paper can explain what gives such a barbule-less structure, I'll just have to wait and see.
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I'll send you the paper a little bit later in the day when my other computer is on (the computer with my papers on it is slow to start up) and I'll read the paper you've linked here in the meantime.
It looks like there may have been a misunderstanding anyway, as it seems all you are actually saying is that these feathers lack barbules. I actually don't have a problem with this. It has happened in ratites after-all (and other flightless birds?). It's the presence of unbranched filaments that I was refuting, of which I still see none. Even this paper is specifically titled "branched integument..."
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"...these feathers lack barbules, it would be very unlikely for these feathers to form a closed pennaceous vane..." (from an earlier comment)
That is mainly all I said about feathers on the animal. You must have misinterpreted because I don't think at any point, I've mentioned unbranched filaments (as you were saying 'single filament' feathers in your original post). And also thanks for the paper.
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It would appear that is the case. No worries.
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Not trying to be impolite but are you sure the secondaries (secondary remiges) attach to the radius instead of the Ulna? I think you might have those mixed up... for example, see [link] these quill knobs on the Velociraptor ulna are probably representing attachment points for the secondaries. Also here is a diagram of a modern bird wing which shows the secondaries are in fact attach to the ulna.
As for the comment on the tertials, I'm not so sure either. If you look at the Thermopolis Archaeopteryx specimen what you will find is impression of fuzzy furrows along the elbow of the animal which might indicate the presence of tertiary remiges (Wellnhofer 2009). And please note, in modern birds tertials are not arranged in the same row as the secondaries.
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Wonderful! I was looking for it!
I was going to do it myself as well, but you've anticipated me! What a coincidence.
Good job
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Really nice image, especially the leg feathering! More people need to start putting fuzz on deinonychosaur legs and toes. Bracketing schmacketing, it's adorable.
I do have a minor critique. To the best of my knowledge (correct me if I'm wrong), an alula has not been found on any deinonychosaurian dinosaurs, and is distinct to "actual" birds. The oldest/most primitive known example of one, I think, is in an enantiornithine.
Also: it's a bit unclear from your diagram, but it is important to note that the secondary remiges (by definition) attach only to the radius, while in your feathered example it looks like they may be somewhat attaching to the humerus as well. As far as I know, tertiaries are not found in deinonychosaurs. Though you don't have them labeled, I don't think that fully formed scapulars are present in this clade either, and are only found in slightly more advanced birds.
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For the Alula, I took Quilnog's Microraptor [link] as a reference, who seemingly put them on Micro's thumb. It could be wrong to call the thumb-feathers of Deinonychosaurs "Alula", but I didn't knew a different name and if they are not the same, they are at least analogues.
Yes, the Remiges secundarii are attached to the radius, I haven't drew it more precise because I thought it should show that the secondaries are on the forearm. They are not attached to the Humerus, the look is because of the overlap.
What looks like Scapulars on the Deinoychosaurian side are simply Pennae conturae generales or body plumage, for that they aren't labeled because they aren't part of the wing-feathers. I guess there should be a gap to make this clear for everyone?
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Yeah, a little gap there might be helpful - I've always considered the "notch" in the wing to be fairly diagnostic of deinonychosauria/basal avalians as opposed to modern birds. Here is a nice picture of Archaeopteryx by Manfred Reichel that gets the shape of the wing across quite well: [link]
As for the alula, I think that Qilong intended to just show that the thumb would be covered in feathers, not that the feathers are specifically adapted to function as an alula. The main difference between alula and plain old "thumb feathers" is that a real alula's feathers are asymmetrical, as they play an important role in steering and lift in powered flight. They are often categorized along with remiges and retrices as genuine flight feathers.
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I know about the Alula-function.
Maybe we call the Thumbfeathers "Pseudalula"?
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Heh, that's a good term for it. I should also point out that it is true that Microraptor has a tuft of feathers on the first digit that most other deinonychosaurs (as well as Archaeopteryx) lack, but I don't believe it is technically considered an alula... but I could be wrong. Either way, I think your image here is supposed to be a "general" template for deinonychosaur arms, and if indeed Microraptor has a "true" alula, it is the exception and not the rule.
Beyond that, very nice work on this, and I hope you don't mind my little nitpicky critiques.
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Nah, I'm happy about every constructive critique and topics to discuss. I'm not that long into our feathery little extinct friends, so I still have many to learn. And how should one learn if he/she isn't alert about errors - that's all part of the learning process.
Hence thank you for nitpicking and don't stop it.
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