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What annoys you about paleontology?; Rant on about moronic theories, complaints, or just animals that annoy you.
Topic Started: Sep 28 2013, 05:04 PM (256,160 Views)
CyborgIguana
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In any case I do share his skepticism that Concavenator had fully-developed, pennaceous feathers akin to those of maniraptorans.
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Furka
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Honestly that thing reminds me more of some Resident Evil enemy than an actual dinosaur ...
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Yi Qi
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Concavenator certainly DID NOT have feathers, what it likely did have was some sort of elongated, independent quill like scale structure.

We have much of its body preserved and it shows typical scales on its body as well as large, rectangular scales on its belly, with some sort of large feet scutes on its feet, akin to those you'd see on the feet of an emu or a rhea.
Edited by Yi Qi, Apr 16 2016, 04:00 PM.
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stargatedalek
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I'm not slow! That's just my moe!

There isn't any evidence that Concavenator lacked feathers. Obviously it wasn't covered head to toe but if you're going to claim that partial scaling equates to a guaranteed lack of any feathering you're demoting yourself to scaley-rex fanboy logic. Honestly "quilled" dinosaurs are just a trope, and an annoying one, created by people who willfully misunderstood the meaning of "quill knobs" and ran with it.

Far more conservative if you ask me to present Concavenator as a minimally feathered animal than to invent an entirely new form of integument just to try and "reign in" feathering within Coelurosaurs.
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Incinerox
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Āeksiot Zaldrīzoti

I would like to add the known flank scales of juvenile Allosaurus to the list of known carnosaur integument. With the data we currently have, that has major implications on the whole clade.

http://dml.cmnh.org/2004Aug/msg00136.html
Abstract


Interpret as you will.
Edited by Incinerox, Apr 16 2016, 07:06 PM.
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CyborgIguana
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Correct me if I'm wrong but I thought scale impressions on Concavenator were limited to the legs and tail.

I agree that it probably wasn't extensively feathered, but I don't see how we can conclude it wasn't feathered at all based on the current evidence. Again, if there's evidence I'm missing feel free to correct me.
Edited by CyborgIguana, Apr 16 2016, 08:29 PM.
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Incinerox
Apr 16 2016, 07:00 PM
I would like to add the known flank scales of juvenile Allosaurus to the list of known carnosaur integument. With the data we currently have, that has major implications on the whole clade.

http://dml.cmnh.org/2004Aug/msg00136.html
Abstract


Interpret as you will.
the area is not large at all. that's like saying because an ostrich has featherless flanks, it has "implications for the whole clade" when we can see that literally every other ratite has very thick feathering across their flanks (except maybe rheas, I'm not sure). Actually, it's worse because Carnosauria is a larger and higher taxa than Paleognathae.
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stargatedalek
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I'm not slow! That's just my moe!

Wow, I never knew before just how small that patch of scales was. And to think so many obsessive JP fans last hopes of scaley redemption rest on it... >:D
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Incinerox
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Flish
Apr 16 2016, 10:06 PM
Incinerox
Apr 16 2016, 07:00 PM
I would like to add the known flank scales of juvenile Allosaurus to the list of known carnosaur integument. With the data we currently have, that has major implications on the whole clade.

http://dml.cmnh.org/2004Aug/msg00136.html
Abstract


Interpret as you will.
the area is not large at all. that's like saying because an ostrich has featherless flanks, it has "implications for the whole clade" when we can see that literally every other ratite has very thick feathering across their flanks (except maybe rheas, I'm not sure). Actually, it's worse because Carnosauria is a larger and higher taxa than Paleognathae.


It is as you say. Ostriches have featherless legs and flanks. Completely bare hide. No scales, no feathers. Nothing. And indeed, it is unique among ratites. Key word being, unique. The ostrich is the exception, not the norm. And since we have both basal and derived carnosaurs, both showing scale impressions, we must by rule of scientific method, assume that scales were the norm among carnosaurs. And since all theropods more basal to the carnosaurs with known integument are scaly, we must by rule of scientific method, assume that this was the ancestral condition. Anything beyond that is speculation.

By your comparison with ratites, it's more like this:
Say ratites went extinct millions of years ago. What we have is like finding a fossil emu with feather impressions, and a rhea with feather impressions, but ostrich remains only yield bone. Are you going to naturally assume that ostriches, based off the known data, had bare flanks? Of course not. So why is it so difficult to use that same simple reasoning if the integument type is switched?

Note: I am not saying at all "NO, IT DEFINITELY DID NOT HAVE FEATHERS". I am saying that all the current evidence points towards scales among carnosaurs being the normal integument, and while it is still within reason to give filamentous or bristled structures to a carnosaur (given how well covered coelurosaurs were, and they're only the next "step" in theropod evolution), it falls under speculation, and not a point I would advise making in a scientific journal.

Another thing, 30cm^2 is not really all that small when the animal in question is about the size of a moderately large dog. Just throwing it out there.

stargatedalek
Apr 17 2016, 12:07 AM
Wow, I never knew before just how small that patch of scales was. And to think so many obsessive JP fans last hopes of scaley redemption rest on it... >:D


@Stargate: "Oh look, I can't provide evidence to refute the opposition's claim, so I'm to be REALLY passive aggressive about it and dismiss their logical arguments as JP fandom stupidity before going back to using equally bogus logic to uphold the opposite extreme along the spectrum of scientific reason!" Nice try. Get out.

Or don't. It's a prime example a particular debate method that really grinds my gears in paleontology.
Edited by Incinerox, Apr 17 2016, 08:43 AM.
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DinoBear
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Incinerox
Apr 17 2016, 08:32 AM
It is as you say. Ostriches have featherless legs and flanks. Completely bare hide. No scales, no feathers. Nothing. And indeed, it is unique among ratites. Key word being, unique. The ostrich is the exception, not the norm.
IIRC Rheas also have similar bald patches, albeit not as extensive.

Still, this patch does show that a decent-but-not-large part of the flank of Allosaurus was indeed scaly (knowing what the patch looks like would be helpful). Doesn't necessarily discount other parts of the animal having feathers, but seems like it definitely did not have a full on body covering like with most coelurosaurs, as you said.
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stargatedalek
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I'm not slow! That's just my moe!

Lighten up I was just making a joke. As you said that's actually decent on such a small juvenile. I'd already shared my legitimate thoughts on this above so I figured I'd try and lighten up an otherwise tense atmosphere.
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Incinerox
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Ahhhh, alright then. The joke aspect of that statement got lost in translation.

It's shocking how many times that logic actually and seriously pops up in these kinds of debates though. The internet is not the best means of conveying sarcasm or satirical tone.
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stargatedalek
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I'm not slow! That's just my moe!

Incinerox
Apr 17 2016, 12:07 PM
Ahhhh, alright then. The joke aspect of that statement got lost in translation.

It's shocking how many times that logic actually and seriously pops up in these kinds of debates though. The internet is not the best means of conveying sarcasm or satirical tone.
Fair enough, my bad for not making that clearer. For future reference if I ever use an emoji of any kind what I'm saying near it should not be taken seriously.

I definitely agree that feathers are not the most conservative assumption for carnosaurs as a whole, but I still think it's silly to invent an entirely new kind of structure unseen in any animal just to write off Concavenators quill knobs as being analogues to literal quills. I do disagree however that the idea of soft integument being basal to archosaurs is unscientific. Whatever way you look at it either several different groups of animals evolved similar soft integument or several different groups of animals evolved scales and lost said soft integument. I just don't think either theory is objectively more likely than the other at this point.
Edited by stargatedalek, Apr 17 2016, 12:27 PM.
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Incinerox
Apr 17 2016, 08:32 AM
Flish
Apr 16 2016, 10:06 PM
Incinerox
Apr 16 2016, 07:00 PM
I would like to add the known flank scales of juvenile Allosaurus to the list of known carnosaur integument. With the data we currently have, that has major implications on the whole clade.

http://dml.cmnh.org/2004Aug/msg00136.html
Abstract


Interpret as you will.
the area is not large at all. that's like saying because an ostrich has featherless flanks, it has "implications for the whole clade" when we can see that literally every other ratite has very thick feathering across their flanks (except maybe rheas, I'm not sure). Actually, it's worse because Carnosauria is a larger and higher taxa than Paleognathae.


It is as you say. Ostriches have featherless legs and flanks. Completely bare hide. No scales, no feathers. Nothing. And indeed, it is unique among ratites. Key word being, unique. The ostrich is the exception, not the norm. And since we have both basal and derived carnosaurs, both showing scale impressions, we must by rule of scientific method, assume that scales were the norm among carnosaurs. And since all theropods more basal to the carnosaurs with known integument are scaly, we must by rule of scientific method, assume that this was the ancestral condition. Anything beyond that is speculation.

By your comparison with ratites, it's more like this:
Say ratites went extinct millions of years ago. What we have is like finding a fossil emu with feather impressions, and a rhea with feather impressions, but ostrich remains only yield bone. Are you going to naturally assume that ostriches, based off the known data, had bare flanks? Of course not. So why is it so difficult to use that same simple reasoning if the integument type is switched?

Note: I am not saying at all "NO, IT DEFINITELY DID NOT HAVE FEATHERS". I am saying that all the current evidence points towards scales among carnosaurs being the normal integument, and while it is still within reason to give filamentous or bristled structures to a carnosaur (given how well covered coelurosaurs were, and they're only the next "step" in theropod evolution), it falls under speculation, and not a point I would advise making in a scientific journal.

Another thing, 30cm^2 is not really all that small when the animal in question is about the size of a moderately large dog. Just throwing it out there.

stargatedalek
Apr 17 2016, 12:07 AM
Wow, I never knew before just how small that patch of scales was. And to think so many obsessive JP fans last hopes of scaley redemption rest on it... >:D


@Stargate: "Oh look, I can't provide evidence to refute the opposition's claim, so I'm to be REALLY passive aggressive about it and dismiss their logical arguments as JP fandom stupidity before going back to using equally bogus logic to uphold the opposite extreme along the spectrum of scientific reason!" Nice try. Get out.

Or don't. It's a prime example a particular debate method that really grinds my gears in paleontology.
Ok, but if you happened to find ostrich impressions with bare skin on the flanks, and then kiwi and cassowary impressions with feathered flanks, What are you to assume about ostriches, and emus and rheas? you really don't have enough evidence to say that either emus or rheas would have featherless flanks, because you don't have evidence to suggest that featherless flanks are unique to ostriches. The difference here is that Concavenator shows evidence of quills and scales, while Allosaurus shows evidence of just scales, so really suggesting that because Allosaurus has scales on a portion of its body so all Carnosaurs must be entirely scaley except for a few exceptions is jumping to conclusions. As Stargatedalek said, we don't really have the evidence currently to deduce whether feathers/quills/fluff/etc. is basal to Dinosauria or if it happened to evolve independently in three or four different occasions.
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Incinerox
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Flish
Apr 17 2016, 12:37 PM
Ok, but if you happened to find ostrich impressions with bare skin on the flanks, and then kiwi and cassowary impressions with feathered flanks, What are you to assume about ostriches, and emus and rheas? you really don't have enough evidence to say that either emus or rheas would have featherless flanks, because you don't have evidence to suggest that featherless flanks are unique to ostriches. The difference here is that Concavenator shows evidence of quills and scales, while Allosaurus shows evidence of just scales, so really suggesting that because Allosaurus has scales on a portion of its body so all Carnosaurs must be entirely scaley except for a few exceptions is jumping to conclusions. As Stargatedalek said, we don't really have the evidence currently to deduce whether feathers/quills/fluff/etc. is basal to Dinosauria or if it happened to evolve independently in three or four different occasions.
Firstly, to humour your given example, you would assume:
> Ostriches had bare flanks, based on the fossil data (which is true).
> Emus had feathered flanks, based on their close relationships with cassowaries (which is true).
> All novaeratitae (kiwis, elephant birds and the casuariformes) had feathered flanks, because kiwis and cassowaries had feathered flanks (which is true).
> Rheas, being outside of the novaeratitae, and closer to ostriches, had bare flanks too (they don't, but this is what you would assume given the fossil data).
> Moas and tinamous (especially tinamous) remain uncertain.

So while we'd have gotten rheas wrong, it's not exactly a bad process. We nailed all Novaeratitae with two fossil specimens. A fossil impression of a rhea with full integument present would change up the notions of where bald-spots in ratites originated, and likely answer questions about moas. Tinamous likely wouldn't even appear where they are in modern ratite cladograms because they're so different - they'd have been interpreted as either basal paleognaths or as galliformes.

But we digress. This still isn't an appropriate comparison with what's going on with Allosaurus and Concavenator.

There is still a division in what we seem to be looking at on Concavenator's arms. The latest paper suggests quill bases, which is a reasonable hypothesis. Others still disagree and believe they were muscle attachment points. There is sound logic for both claims.

First thing I want to note very briefly is that no other carnosaur is known to have these structures. You could argue preservation bias, but with 40+ allosaurus specimens, you'd think we'd have something by now if they occured in Allosaurus.

Second thing I want to note is that it's rather odd for quills to pop up in one species of carnosaur, when they don't show up again until ornithomimids and maniraptorans. Not even basal coelurosaurs have such deeply embedded quills.

Do with those two points as you will, just food for thought. But the fact that we lack these structures in a genus as well documented as Allosaurus, or fellow basal carcharodontosaurid Acrocanthosaurus (with arms completely known to articulation), and derived carcharodontosaurid Tyrannotitan (which, to be fair, is in nowhere near as good a shape as Acro's remains), suggests that Concavenator was an oddball in more ways than just the obvious back problem (I wouldn't be surprised if it and Becklespinax turned out to be the same animal).

Granted, MOST carnosaur genera are known from very fragmentary remains, and nothing from the arms, so again, it could be preservation bias.

The thing that matters here is that regardless of whether many or all had arm quills or not, the combined data available for carnosaur skin covers a large enough area, and its similarity to known data from more basal clades (which are known to be extensively covered in such scales), allows us to say with a degree of confidence that feathers were unlikely among carnosaurs as a group.

What this implies for the dinosaurs as a whole remains to be seen. When I referred to ancestral taxa, I was referring to the "original" carnosaur.
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