Shop Mobile More Submit  Join Login
×




Details

Submitted on
October 31, 2010
Image Size
143 KB
Resolution
900×451
Link
Thumb
Embed

Stats

Views
4,939
Favourites
48 (who?)
Comments
43
Downloads
63
×
Hypothetical Evolution of Feather Distribution by Albertonykus Hypothetical Evolution of Feather Distribution by Albertonykus
Possible evolution of feather distribution and feather types based on current knowledge, counter clockwise from bottom left (not to scale):
Whatever-Juravenator-and-Sciurumimus-are grade (represented by Juravenator starki) - Scales on tail and hindlimbs. Protofeathers or plumulaceous feathers on at least the top edge of the tail and probably much of the body. (A lot of the fossilized feathers formerly assumed to be "protofeathers" are probably more advanced than they look. Studies on the effect of crushing on bird carcasses show that, when crushed, the pennaceous body feathers of modern bird resemble the supposed "protofeathers" of basal coelurosaurs. So the "protofeathers" in basal coelurosaurs are likely at least plumulaceous feathers in reality, while those reported in more derived taxa are almost certainly true pennaceous feathers.)

I know, many suggest that feathers originated at the base of Dinosauria due to the presence of feather-like integument in certain ornithischians, but even if the fuzz of heterodontosaurids and theropods are homologous, we do not know enough about the feathers (if present) of taxa outside of whatever the least inclusive clade including both Juravenator/Sciurumimus and maniraptors is (possibly Coelurosauria, possibly Orionides if Sciurumimus and Juravenator are megalosauroids) to say much on the subject. (There's another non-coelurosaur theropod that's said to preserve evidence of feathering on the arms in the form of quill knobs, Concavenator corcovatus, but this is dubious. The "quill knobs" are on the "wrong" side of the ulna, are irregularly spaced, and appear to match an intermuscular line that's present in crocodilians, so they might be for muscle attachment instead.)

Compsognathid (and lots-of-basal-coelurosaurs-that-might-be-compsognathids) grade (represented by Sinocalliopteryx gigas) - Protofeathers or plumulaceous feathers on tail, torso, forelimbs, and legs, extending onto the foot in at least Sinocalliopteryx. Integument on underparts and snout unknown. Like Juravenator, Compsognathus longipes had scales on at least part of its tail, but this is not known in other taxa from this grade. Maybe they had scales on the sides and underside of the tail with feathers on the dorsal surface, but these feathers were so long that they would cover up the scales in life. One undescribed taxon appears to have some EBFFs, long bristle-like feathers. However, it's not unlikely that some taxa currently grouped in Compsognathidae are not actually compsognathids. There's a paper in the works (or so I've read) that suggests there's only one other known taxon (besides Compsognathus itself) that belongs in Compsognathidae proper, while other "compsognathids" are scattered elsewhere around Coelurosauria or even Tetanurae. So watch this space.

Tyrannosauroid grade (represented by Dilong paradoxus, with inferences from Yutyrannus huali) - Phylogenetic bracketing isn't a lot of help here. Full-body preservation of tyrannosauroid integument is unknown, and a lot of the little bits and pieces we have are still unpublished. Dilong preserves protofeathers or plumulaceous feathers on the dorsal surface of the tail and behind the jaw, while Yutyrannus preserves them on the tail, neck, forelimbs, and feet. Some of the feathers preserved in Yutyrannus and an undescribed tyrannosauroid may be EBFFs. Tyrannosaurid skin impressions from at least the underside of the tail and feet show scales, and patches of naked skin (with very fine scales) are reportedly known (but unpublished) in at least Gorgosaurus libratus and possibly others. It might be worthy to note that some have suggested Dilong paradoxus might not actually be a tyrannosauroid, but most other analyses don't support this so I'll let it slide for now. As you can see, basal coelurosaur phylogeny is still very, very messy.

Therizinosaur grade (represented by Beipiaosaurus inexpectus) - EBFFs and protofeathers or plumulaceous feathers on the neck, legs, and tail. Long protofeathers or plumulaceous feathers on the arms. Face probably mostly naked at least in Bepiaosaurus. Integument elsewhere unknown. Here restored as being fully fuzzy except for the toes based on more derived maniraptors.

Ornithomimosaurs appear to have been similar in distribution and structure of feathers. Feather markings on the forelimb bones of Dromiceimimus brevitertius suggest pennibrachiae (wings) may have been present in the adults, possibly (but not certainly) formed by pennaceous feathers.

Oviraptorosaur grade (represented by Similicaudipteryx yixianensis) - Symmetrical pennaceous feathers all over the body, particularly on the wings and tip of the tail, scales or naked pads possibly present on the fingers, naked on the tip of the upper jaw and beaked on the lower (ceanagnathoids have beaks on both jaws). Usually had primaries and secondaries as adults, except for Caudipteryx zoui, which only had primaries. Juveniles lacked secondaries.

Deinonychosaur and assorted-basal-paravians grade (represented by Microraptor zhaoianus) - Pennaceous feathers all over the body, particularly on the wings, tail, and feet. The tip of the snout was naked. Juveniles had fluffy down instead of fully developed wing feathers. Feathering on the legs variable, often covering at least the metetarsals, with some taxa going down further, sometimes covering even the toes. Taxa without feathers on toes had scales there. Wing feathers asymmetrical in flying taxa, symmetrical in flightless (or near-flightless) ones. Fully flightless taxa had degraded feathers that didn't form a closed vane, similar to the feathers of many modern flightless birds such as struthioniforms. At least one taxon (Microraptor zhaoianus) had feathers on the thumb, akin to an alula. Microraptor also preserves a pair of streamer-like tail feathers in the middle of its tail fan. A feathered crest may have been present in Anchiornis huxleyi, but the one thought to be preserved in Microraptor has been shown to be an artefact caused by crushing. Long pennaceous feathers on tail restricted to the tip in some taxa, present along the entire length in others.

Confuciusornithid grade (represented by Confuciusornis sanctus) - Had primaries and secondaries, naked fingers, and pennaceous feathers all over body. Retained long leg feathers, though not as exaggerated as in more basal paravians. It is unknown if tertials were present. Confuciusornithids had beaked snouts, but these evolved independently from those of modern birds. Some specimens (probably males) had a pair of long ribbon-shaped tail feathers.

Enantiornithine grade (represented by Shanweiniao cooperorum) - Had pennaceous feathers all over body, usually including the snout (which is beaked, half beaked or naked in some taxa). Also had alulas, which more basal maniraptors usually lacked. At least some retained long leg feathers, though not as exaggerated as in more basal paravians. Most didn't have a tail fan, but either had no long retrices at all or a pair of ribbon-shaped tail feathers similar to that of confuciusornithids, though generally not as long. Shanweiniao cooperorum is known to have had a "tail fan" (different from the tail fans of ornithurines), with at least four ribbon tail feathers instead of two.

Euornithines (represented by Passer domesticus) - Pennaceous feathers all over body, except the beaked snout in neornithines and usually scaly feet. The feathering of the legs is variable, however, and ranges from mostly naked to fully feathered. Loss of long leg feathers. Have primaries, secondaries, tertials, alulas, and tail fans.

I have not included the scansoriopterygids, although they do preserve some integument. Only two scansor taxa are known so far. One, Scansoriopteryx heilmanni, had scales underneath its long tail (but I've seen it suggested that these scales are actually from the legs) with downy feathers on the wings, body, and tail. (It's a juvenile, so its adult feathers are unknown.) The other, Epidexipteryx hui, had long ribbon-like tail feathers on its short tail and some pennaceous feathers on the body, but doesn't appear to preserve any wing feathers. Some say that Epidexipteryx might actually be the adult form of Scansoriopteryx, with the tail shortening as the animal reaches maturity. (This isn't as far fetched as it sounds, as the juveniles of some Mesozoic birds, such as confuciusornithids, had longer tails than the adults.) With all these uncertainties, it's difficult to figure out how the integument of scansors were arranged and their exact placement in the coelurosaur tree.
Add a Comment:
 
:iconspongebobfossilpants:
"There's a paper in the works (or so I've read) that suggests there's only one other known taxon (besides Compsognathus itself) that belongs in Compsognathidae proper, while other "compsognathids" are scattered elsewhere around Coelurosauria or even Tetanurae. So watch this space."

Wow. Do you have references for this?
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Aug 25, 2014
I probably got that from an old Tet Zoo post. A lot of things have changed since then, so I don't know if Darren's analysis still supports that result. I suppose we'll have to wait.
Reply
:icondinobirdman:
DinoBirdMan Featured By Owner Jun 7, 2013  Student Artist
You must be re-updated your drawing with digital art!:)
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Jun 7, 2013
Yep!
Reply
:icondinobirdman:
DinoBirdMan Featured By Owner Jun 7, 2013  Student Artist
I hope what are you doing, next?;)
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Jun 7, 2013
I'll probably revisit more old drawings, then I'll give creating entirely new ones a shot.
Reply
:icondinobirdman:
DinoBirdMan Featured By Owner Jun 7, 2013  Student Artist
That's good!;)
Reply
:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Nov 9, 2012
Of course, the next update will have to include Sciurumimus and the feathered ornithomimosaur…
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Nov 9, 2012
Yep... I don't have space on the page to add anymore extra dinosaurs, so I'll probably have to change the therizinosaur to an ornithomimosaur or something.
Reply
:iconzachory:
zachory Featured By Owner Apr 16, 2012
Hi I find this interesting. It's almost like one someone did on the evolution of bats!
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Apr 16, 2012
Thanks; that sounds very cool. There's isn't as much known in that area is there?
Reply
:iconzachory:
zachory Featured By Owner Apr 16, 2012
no not that I know of
Reply
:iconjd-man:
JD-man Featured By Owner Apr 14, 2012
"we do not know enough about the feathers (if present) of taxa outside of whatever the least inclusive clade including both Juravenator and maniraptors is (which may be some clade within Coelurosauria, but the word on the street is that Juravenator may turn out to be a non-coelurosaur theropod) to say much on the subject."

That reminds me of the "Evolution of Allosaurus?" thread. It'd be cool if Juravenator was representative of the common ancestor of avetheropods.
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Apr 14, 2012
Or even of Tetanurae, if "Otto" (said to be very similar to Juravenator) turns out to be a megalosauroid.
Reply
:iconjd-man:
JD-man Featured By Owner Apr 15, 2012
I assume "Otto" is a currently-undescribed specimen? Where'd you find out about it?
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Apr 15, 2012
Yes, a photo of it turned up on the Internet last year. I heard it got through review last year as well, so we should be seeing it fairly soon. The big news about this one is reportedly that it's a feathered megalosauroid, but wait for the paper I guess.
Reply
:iconjd-man:
JD-man Featured By Owner Apr 15, 2012
Thanks for the reminder. I read about Otto last year, but had since forgotten about it.
Reply
:iconcrash-the-megaraptor:
Crash-the-Megaraptor Featured By Owner Apr 14, 2012  Hobbyist Traditional Artist
Hmm...would certainly be useful in my newest art project. X3
Reply
:iconspongebobfossilpants:
SpongeBobFossilPants Featured By Owner Dec 4, 2011
"Oviraptorids have beaks on both jaws"
What about caenagnathids?

Is it just me, or is Similicaudipteryx your go-to oviraptorosaur?
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Dec 4, 2011
Caenagnathids (whatever they may be) do as well.

It used to be Caudipteryx, but with the lack of primaries being unusual I switched out in this case for Similicaudipteryx. I could have used C. dongi instead I suppose.
Reply
:iconaustroraptor:
Austroraptor Featured By Owner Dec 15, 2010  Hobbyist General Artist
i am convinced it is a coelurosaur now tough, now i want to draw one :P
Reply
:iconaustroraptor:
Austroraptor Featured By Owner Dec 15, 2010  Hobbyist General Artist
sorry to spam your comment box Albertonykus but that guy erioguez is been doing on my nerves

Anyway: I can't say i ain't doubtfull about juravenator placement on the dinosaur tree still, starting from the fact that "Compsognathidae" might not be a monophyletic group
Reply
:iconaustroraptor:
Austroraptor Featured By Owner Dec 15, 2010  Hobbyist General Artist
Erioguez, shut up and stop stalking me please
Reply
:iconaustroraptor:
Austroraptor Featured By Owner Dec 5, 2010  Hobbyist General Artist
Besides Conca would only prove carnosaurs to have integument, not ceratosaurs
Reply
:iconaustroraptor:
Austroraptor Featured By Owner Dec 5, 2010  Hobbyist General Artist
Well i meant basal to coelurosauria as you said, basal to dilong, jura and crew, but yes, indeed i think fuzz is basal to dinosauria,

Basically, because we find scales on something doesn't mean it doesn't have any assortment of fuzz, i do believe most dinosaur clades but Iguanodontians, Sauropods,Ceratosaurs and Tyreophorans, and i do believe Ceratosaurs are secondarily featherless, evolving from a fuzzy ancestors and loosing their feathers

But i have no way to prove that as, sadly, concavenator knobs were proven to be muscle anchoring points
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Dec 5, 2010
Juravenator shows that scales and feathers can coexist (which is why I think tyrannosaurids likely had feathers even though there are a few skin impressions of scaly tyrannosaurid skin), but we have very complete records of skin on hadrosaurs, titanosaurs, and Carnotaurus that show nothing but scales. (Of course, one could argue that conditions that preserve scales wouldn't necessarily preserve feathers, which is why we really need more fossils.) Furthermore, I'm not so sure it's possible for feathers to revert back to scales, although that's debatable.
Reply
:iconaustroraptor:
Austroraptor Featured By Owner Dec 5, 2010  Hobbyist General Artist
Thats really interesting! tough i still personally think feathers are basal to coelurosauria, and here's why i take this hypothesis:

[link]|en&tbb=1&ie=utf-8

BTW, thanks for fave-ing my rex and my epi!
Reply
:iconeriorguez:
Eriorguez Featured By Owner Dec 15, 2010
[link]

A bit adamant on Jura being an allosauroid and compsognathids not having scales, are you? Despite being told otherwise, you rather chose to go with the view that you like more, in spite of the lack of suport for that.
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Dec 5, 2010
That link doesn't work, but being a regular Theropoda reader I think you mean the idea that feathers are basal to Dinosauria? I'm still kind of skeptical given the extensive scales known in sauropods, hadrosaurs, and ceratosaurs, but we really need more fossils... I certainly agree that feathers are basal to Coelurosauria, or whatever the clade containing Juravenator, Sinosauropteryx, Sinocalliopteryx, Dilong, and maniraptors is.

And you're welcome!
Reply
:iconspongebobfossilpants:
Will you update this (as Jura is, once again, a probable non-coelurosaur)?
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Mar 11, 2012
I'll probably leave Juravenator in the picture itself but edit the text if it turns out to be a non coelurosaur.
Reply
:iconaustroraptor:
Austroraptor Featured By Owner Nov 28, 2010  Hobbyist General Artist
Wow really? Heheh those tiny dinosaurs are so confusing :P
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Nov 29, 2010
Right on time: a new study on Juravenator ([link]) suggests that it is indeed a coelurosaur, and most likely a compsognathid if Compsognathidae is a natural group. Also, the fibers do appear to be protofeathers, and were more extensive than previously thought.
Reply
:iconaustroraptor:
Austroraptor Featured By Owner Nov 27, 2010  Hobbyist General Artist
Well turns out that Juravenator likely isn't a coelurosaur at all (Atleast according to darren naish that spent a lot of time with the fossil), but a neotenic carnosaur, opening a huge possibility that down was tehre before coelurosauria

-Source: Tetrapod zoology blogspot

[link]
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Nov 27, 2010
I think what he's saying is that it looks like a carnosaur, but it still comes out as a coelurosaur in analyses. So it's a possibility, but there isn't a whole lot of support yet.

By the way, Sinosauropteryx is sometimes said to be carnosaur, too.
Reply
:iconspongebobfossilpants:
"By the way, Sinosauropteryx is sometimes said to be carnosaur, too."

Link (other than Thescelosaurus!), please?
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Mar 11, 2012
Nick Longrich presented on it in an SVP meeting. It's mentioned in place like :iconmattmart:'s website ([link]) and Wikipedia ([link]).
Reply
:iconmattmart:
MattMart Featured By Owner Nov 1, 2010  Hobbyist Digital Artist
Great overview! Just to nitpick, the contour feathers of confuciusornithids to appear to be pennaceous (and some on Anchornis and Archaeopterx, and possibly Microraptor, but not all across the body). And Shanweiniao only has a 'tail fan' in that it has four ribbon feathers rather than two. I'm not sure if the pygostyle was plough-shaped or not (pre-requisite for true ornithurine fan tails), gotta read that paper again...

Every new discovery just seems to complicate this whole picture rather than clear it up. Here's to more fossils filling in the gaps!
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Nov 1, 2010
I was hoping you'd come along and do some nitpicking. Thanks!
Reply
:iconbabbletrish:
babbletrish Featured By Owner Oct 31, 2010  Professional Traditional Artist
Terrific reference!
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Nov 1, 2010
Thank you!
Reply
:iconntamura:
NTamura Featured By Owner Oct 31, 2010
Very enlightening my friend! :)
Reply
:iconalbertonykus:
Albertonykus Featured By Owner Nov 1, 2010
Glad you liked it!
Reply
Add a Comment: