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Post by sid on Apr 13, 2011 7:46:23 GMT
To Griffin: yeah, more or less... But i don't think it's too far-fetched, especially regarding the smaller dinos
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Post by dinoguy2 on Apr 13, 2011 13:39:45 GMT
You're not in favour of the idea that 'fuzz' could have originated early in the evolution of the Ornithodira then, MM? I think it's likely that some kind of dermal quill is primitive for Ornithodira (basically, EBFFs aka stage 1 feathers), but I wouldn't go so far as to say Tianyulong type "fuzz" is. I think if it were, we'd see it in a more diverse sample of small-bodied species and juveniles of larger species. The fact that so most ornithischians and sauropods are fuzz-free implies that whatever the basal structure was, it was easy to lose. A fuzzy coat is too beneficial to be lost so easily, IMO. But I could be proved wrong at any time
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Post by Griffin on Apr 13, 2011 20:04:59 GMT
To Griffin: yeah, more or less... But i don't think it's too far-fetched, especially regarding the smaller dinos Yeah just wanna make sure I dont read something by somebody defending "Pachycephalosaurs def had feathers and quills weeee!" as if it were a fact. We have enough of that going on as it is lol
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Post by sid on Apr 13, 2011 22:45:59 GMT
Eh eh, you're right...
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Post by gwangi on Apr 14, 2011 2:35:45 GMT
If ceratopsians had quills I like to think of them as being like those on Mark Witton's styracosaurus. As for fuzz being the primitive condition for Ornithodira I sure find it fun to speculate and at least some evidence seems to point that way. Either pterosaurs, theropods and ornithischians all evolved fuzz independently or they share a common ancestor who possessed fuzz, which seems more likely?
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Post by Griffin on Apr 14, 2011 2:44:57 GMT
If its a common ancestor then pretty much all dinosaurs would have fuzz in their family history somewhere down the line. In that NAT geo article about feathers they went as far as to say that even the ancestors of crocodillians may have had "feathers" originally.
Personally I really don't know. I'm still hesitant to put fuzz on onnithiscians beyond quills on basal ceratopsids and heterdontosaurs.
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Post by Seijun on Apr 14, 2011 3:53:31 GMT
Is that styraco eating a raptor? That would be cool if it was. Many modern herbivores will occasionally dine on meat.
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Post by Griffin on Apr 14, 2011 3:58:22 GMT
I think its supposed to be some small tyrannosaur. But yeah that illustration went along with an article entertaining the idea of omnivorous ceratopsids. Sorta like modern pigs. Its possible I guess?
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Post by Horridus on Apr 14, 2011 16:38:25 GMT
I'm still hesitant to put fuzz on onnithiscians beyond quills on basal ceratopsids and heterdontosaurs. Tianyulong had more than just 'quills', though.
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Post by stoneage on Apr 14, 2011 17:16:49 GMT
I'm still hesitant to put fuzz on onnithiscians beyond quills on basal ceratopsids and heterdontosaurs. Tianyulong had more than just 'quills', though. ;D Well it's debatable! Tianyulong had filamentous integumentary structures that may have had quills or barbs. There are no fozzilized feathers. Tianyulong is more closely related to Triceratops and Stegosaurus then theropods. However if they do turn out to be feathers, that would probably mean that feathers were around before the Saurischia and Ornithischia split. Which would mean feathers probably developed before dinosaurs. Now all we need to do is find sauropods with feathers. ;D
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Post by Horridus on Apr 14, 2011 17:20:56 GMT
What I meant was that it doesn't just have Psittacosaurus-style quills - it actually has quite a covering. It makes sense that the structures are more similar overall to those on Psittacosaurus, though, than those on theropods as the they are more closely related (being both ornithischians).
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Post by stoneage on Apr 14, 2011 17:25:59 GMT
What I meant was that it doesn't just have Psittacosaurus-style quills - it actually has quite a covering. ;D Wait a minute. How do you know it doesn't have Psittacosaurus-style quills? I mean Tianyulong is more closely related to Psittacosaurus then theropods. The homology alone could infer that they were the same.
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Post by Horridus on Apr 14, 2011 17:29:08 GMT
;D Wait a minute. How do you know it doesn't have Psittacosaurus-style quills? I mean Tianyulong is more closely related to Psittacosaurus then theropods. The homology alone could infer that they were the same. Aaarggh, I meant just in terms of the covering that it has! It has a more substantial 'coat' than Psittacosaurus. As I said the quills are of a similar type nonetheless. I just worded it badly. I shouldn't drink beer in the afternoon.
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Post by paleofreak on Apr 14, 2011 19:20:17 GMT
;D Wait a minute. How do you know it doesn't have Psittacosaurus-style quills? Simply look at the fossil. There is no quills. Tere is "fur" covering, coelurosaur-style.
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Post by Griffin on Apr 14, 2011 20:40:41 GMT
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Post by gwangi on Apr 14, 2011 20:48:51 GMT
I think its supposed to be some small tyrannosaur. But yeah that illustration went along with an article entertaining the idea of omnivorous ceratopsids. Sorta like modern pigs. Its possible I guess? It is a small tyrannosaur. The article that went with it was quite interesting and it makes a lot of sense. I can see ceratopsians as pig like animals eating whatever they came across and bullying around small predators. Lets face it, not all dinosaurs were carnivores or herbivores, there must have been omnivores as well.
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Post by paleofreak on Apr 14, 2011 21:33:37 GMT
Arent those more similar to the stuff on psittacosaurus? Well, the fibers shown in that picture are the longest ones in Tyanyulong. They are on the tail and measure 60 mm. The Psittacosaurus' tail feathers are 160 mm long according to my info. The longest fibers in Sinosauropteryx are about 35 mm long. In my impression Tianyulong fibers look "intermedial" between Sinosauropteryx and Psittacosaurus in size, density and stiffness. On the other hand, Tianyulong preserves shorter fibers below the neck, so they seem to cover the body or a big part of it. A coat, as in small coelurosaurs, not an "ornament" as in the scaly Psittacosaurus
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Post by zopteryx on Apr 15, 2011 4:30:21 GMT
Just thought of something. What about the organization of pennaceous feathers on the "wings" of certain dinosaurs. Were they layered like on a bird's wing (3 layers?), or simpler in organization?
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Post by dinoguy2 on Apr 15, 2011 15:53:43 GMT
I think what he means is that Psittacosaurus only has a few quills on a small patch of its tail. Those quills are long and stiff, like the quills of a porcupine, and not very fur-like.
Tianyulong has similar long, stiff quills on its tail and back. It *also* has shorter, softer filaments covering the rest of its body. How similar these are to the long, stiff quills in terms of structure has not been studied or published on yet. But just looking at the fossil, they're definitely more fur-like in appearance than anything on Psittacosaurus.
Also, apparently there are unpublished specimens of tianyulong that show the "fur" stuff much better than the original fossil, where the fur is very sparse; most seems to have decomposed. You can really only see it on the underside of the neck and around the longer quills so it's hard to see the difference in low-res photos or diagrams.
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Post by paleofreak on Apr 15, 2011 16:33:19 GMT
I think what he means is that Psittacosaurus only has a few quills on a small patch of its tail. Those quills are long and stiff, like the quills of a porcupine, and not very fur-like. The Psittacosaurus "hairs" are softly bended. they look less stiff than porcupine quills. Oh, please, do you have a link or something...?
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