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Sooo, dinosaurs have officially turned into birds
Topic Started: Nov 3 2012, 08:13 AM (10,710 Views)
Godzillasaurus
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Not in the evolutionary sense, but in the sarcastic sense. Dinosaurs used to be large, scaly, beasts. Now, everyone thinks they all (yes, including sauropods) had feathers. If there have been countless dinosaur skin-impressions, and only a couple feathered non-ceoulosaur theropods, I guess that just puts feathers on every dinosaur, even when the evidence states otherwise. Anyone else bothered by this? :angry:
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SpinoInWonderland
The madness has come back...
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FelinePowah
Nov 8 2012, 06:36 PM
ThisPosted Image looks far cooler

The this
Posted Image
This
Posted Image
dominates over them both
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Cat
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Omnivore
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theropod
Nov 4 2012, 12:34 AM
what is the point of fur on an elephant? what´s the point of tiny remains of hair in some cetaceans? they would reduce feathers undoubtedly, maybe so far that they wouldn´t be externally visible. nevertheless the normal state among dinosaurs is to be feathered, not the other way around.
Look, my friend, elephants have no more fur than supermodels have mustachioes. Fur is a thick covering of noticeably long hair. Technically, elephants and whales have haired bodies. So does Charlize Theron. In practice, they are all hairless as eggs. The problem is that when people hear of 'feathered' dinos they imagine giant turkeys. There are only few dinos who are proved to look like giant turkeys. Those 'scaled' impressions may not reveal thin, almost microscopic filaments, but those would be irrelevant about how dinos looked like. So it is, to say the least, quite premature to 'redraw hundreds of dino images'. Unless somebody don't want to draw fantasy animals, in that case they are welcome to post their work of art in the spam section.
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Admantus
Herbivore
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FelinePowah
Nov 8 2012, 06:36 PM
ThisPosted Image looks far cooler

The this
Posted Image
No. Remove the second one. It's burning my eyes.
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Cat
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Omnivore
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The second one is basically a 'cartoon' dinosaur, so it's even more fantastic than the others.
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SpinoInWonderland
The madness has come back...
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real dinosaurs are always better than cartoon dinosaurs, 100% of all time
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theropod
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Cat
Nov 8 2012, 06:58 PM
theropod
Nov 4 2012, 12:34 AM
what is the point of fur on an elephant? what´s the point of tiny remains of hair in some cetaceans? they would reduce feathers undoubtedly, maybe so far that they wouldn´t be externally visible. nevertheless the normal state among dinosaurs is to be feathered, not the other way around.
Look, my friend, elephants have no more fur than supermodels have mustachioes. Fur is a thick covering of noticeably long hair. Technically, elephants and whales have haired bodies. So does Charlize Theron. In practice, they are all hairless as eggs. The problem is that when people hear of 'feathered' dinos they imagine giant turkeys. There are only few dinos who are proved to look like giant turkeys. Those 'scaled' impressions may not reveal thin, almost microscopic filaments, but those would be irrelevant about how dinos looked like. So it is, to say the least, quite premature to 'redraw hundreds of dino images'. Unless somebody don't want to draw fantasy animals, in that case they are welcome to post their work of art in the spam section.
There is not one single dinosaur proven to be a giant turkey, the only dinosaur that does resemble a turkey is the turkey itself. I can´t help the stupid guys that equate a feathered dinosaur with a giant turkey

I´m not talking about the superficial look of them, as I said in large ones you´d probably see about as many feathers as hair in elephants, but I´m talking about the actual presence of biological traits and abotu the fact that these traits where most likely far more widespread than you think, whether they were superficially a prominent character or not.


PS: the second deinonychus picture is an insult to palaeontology!
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JD-man
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Jinfengopteryx
Nov 3 2012, 06:05 PM
Have you read the comments under your blog entry? It's not that likely that Sciurumimus was a Coelurosaur. All you have is a blog entry, where he showed the possibility that it MAY have been a Coelurosaur, while we have a sciensifitic paper stating it to be a Megalosaur. Really, it is sharing lot's of similarities with Meglosaurs. Read Rauhuts ******** paper!


No offense, but it's not as clear cut as you make it out to be: For 1, it's a juvenile & "problems occur when you go around producing taxonomy for species based on juveniles, because some features that diagnose adults do not appear until well along in age" ( http://qilong.wordpress.com/2012/07/27/the-squirrel-imitator/ ); For another, Cau's analysis "included more coelurosaur species, so I'd tend to put more stock in that one" ( http://Albertonykus.deviantart.com/journal/Otto-312279124 ).

Jinfengopteryx
Nov 4 2012, 02:14 AM
For the last time, I don't believe in feathered Sauropods, my problem is that you acted like it's proven that they had no feathers.


To be fair, "the embryonic titanosaurs from Auca Mahuevo have full-body skin casts" ( http://dml.cmnh.org/2011Sep/msg00129.html ).

theropod
Nov 4 2012, 07:38 AM
Also, the protofeathers of some theropods are said to be just the same as the quills in Tianyulong (beipiaosaurus for example). This just shows how related the two forms are.


Actually, they're said to be "very similar. Whether these turn out to be formed by convergence with theropods or retention in both groups of some ancestral dino-fuzz is not yet certain" ( http://www.geol.umd.edu/~tholtz/G104/lectures/104aves.html ).

theropod
Nov 4 2012, 07:38 AM
But unfortunately for you heterodontosauridae is not part of ornithopoda, and mostly acknowledged to be a very basal clade of Ornithischia.


Actually, it's still possible (if not probable) that heterdontosaurids were primitive ornithopods (See the Butler/Barrett quote). Sereno 2012 ( http://www.pensoft.net/journals/zookeys/article/2840/abstract/taxonomy-morphology-masticatory-function-and-phylogeny-of-heterodontosaurid-dinosaurs ) shows that, at the very least, they were neornithischians (as opposed to primitive ornithischians).

Quoting Butler & Barrett ( http://www.amazon.com/Complete-Dinosaur-Second-Life-Past/dp/0253357012/ref=sr_1_1?s=books&ie=UTF8&qid=1360481558&sr=1-1 ):
Quote:
 
The phylogenetic position of heterodontosaurids is extremely problematic. Nevertheless, most workers have suggested that heterodontosaurids are the most primitive ornithopods (e.g., Sereno 1986; Norman et al. 2004), with the consequent implication that Ornithopoda originated during the Late Triassic. More recently, two alternative hypotheses have been proposed. Many paleontologists have now suggested that the heterodontosaurids were the sister clade to Marginocephalia (ceratopsians and pachycephalosaurs: e.g., Xu et al. 2006). In contrast, it is possible that heterodontosaurids represent some of the most primitive ornithischians, a position that would fit well with their early appearance in the fossil record (Butler et al. 2007, 2008; Zheng et al. 2009).
Edited by JD-man, May 26 2013, 01:28 AM.
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Jinfengopteryx
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I already know Cau's blog entry about that now, but I did not know it when I posted this.
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JD-man
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theropod
Nov 4 2012, 08:01 AM
Posted Image
think about it this way: which is more likely, that all these groups did develop their filaments independently, or that their common ancestor had some sort of filamentous integument that developed slightly different shapes or stayed in an ancestral condition in some, attained a derived one in others or was secondarily lost or reduced? Consider we have little evidence AGAINST a body covering in those in between, but a lot of evidence for it in many taxa. By mere likelyhood it is clear which is the most probably, isn´t it?


No offense, but it's not as clear cut as you make it out to be: In reference to megalosauridae, Sciurumimus was probably a coelurosaur ( http://translate.google.com/translate?u=http%3A//theropoda.blogspot.com/2012/07/sciurumimus-albersdoerferi-rauhut-et-al.html&hl=en&langpair=it|en&tbb=1&ie=UTF-8 ); In reference to carcharodontosauridae, Concavenator probably lacked proto-feathers (See "Allosauroids with proto-feathered arms?": http://scienceblogs.com/tetrapodzoology/2010/09/09/concavenator-incredible-allosauroid/ ); In reference to ornithischians, see my previous post.

theropod
Nov 4 2012, 07:30 PM
actually that´s not true. ornithischians which are all herbovires have a birdlike pelvis, while most saurioschians, including most theropods and sauropods, have a "lizard hip". the birdlike pelvise only quite recently evolved analogous in maniraptorans. The herbivores being less birdlike is merely a matter of perspective. of course, if you ignore all the findings of filaments in them they might seem less birdlike, but if you consider the facts they are probably just as likely to have integument and non-avian dinosaurs alltogether where probably even more similar to aves than tought


Godzillaman
Nov 5 2012, 12:15 AM
Correction: Theropods and sauropods were lizard hipped (not including birds of course). All of the other herbivorous dinosaurs were bird hipped.


While you're both right to correct Black Ice, you're also both wrong in 1 very important way: Regardless of the common names (in this case, lizard-hipped), birds are saurischians for the same reason they're dinos: To paraphrase Holly ( http://darwinwasright.homestead.com/UranFnMonkeyMate.html ), "They evolved from saurischians. Their ancestors were saurischians. They're descended from saurischians. They are saurischians."

Jinfengopteryx
Feb 10 2013, 07:04 PM
I already know Cau's blog entry about that now, but I did not know it when I posted this.


Just making sure.
Edited by JD-man, Feb 11 2013, 03:41 AM.
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theropod
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^I didn't write they wheren't, of course birds are saurischians, for the same reasons they are dinosaurs as you note yourself. Obviously, the ornithischian pelvis is a mere homoplasy. I think that fact is so obvious it can be regarded general knowledge. I'm just rejecting the claim that ornithischians where not birdlike, as I think all dinosaurs share many birdlike features.

I wouldn't say "probably", "maybe" or "possibly" would be more appropriate. After all, there is more to a cladistic analysis than the mere inclusion of lots of taxa (of course that's important), but weighing features is too important. I tend to trust human analyses in such regards, as no computer has so far given me an explanation why an animal should have megalosauroid features but be a coelurosaur.
After all, Rauhut and collegues even give features that it differs from coelurosaurs in.

[IMG]The maxilla has a marked kink in the anterior margin of the ascending process dorsally and a large maxillary fenestra, which is closed medially (Figs. 1B and 2A), as in other megalosaurids (9, 10). A small premaxillary fenestra seems to be present under the overhanging anterior rim of the antorbital fossa. The maxillary antorbital fossa anterior to the antorbital fenestra accounts for ∼23% of the total length of the antorbital fossa, as in other basal tetanurans but unlike coelurosaurs, in which it typically accounts for 40% or more ofthe antorbital fossa (11). The lacrimal has a long, thin anterior process, which laterally forms a large lacrimal antorbital fossa that is continuous between the dorsal and ventral part of the vertical strut, in contrast to most theropods but similar to Torvosaurus (12).[/IMG]

Quote:
 
A broad and deep longitudinal fossa is present on the posterior face of the basioccipital bone below the occipital condyle (Fig. 2B), as seen in other megalosaurids and spinosaurids (10).


Quote:
 
The coracoid is oval, is shorter than it is high, and lacks a subglenoid process and a biceps tubercle, as seen in megalosaurids and spinosaurids. The left ramus of a small, slender furcula is exposed.


Quote:
 
Digit I is very robust, with phalanx I-1 exceeding the radius in width, as in compsognathids (14), and the ungual is more than half the length of the radius.


I can count four traits that it shares with megalosaurs, countless ones that are similar to other basal tetanurans, one that it shares with compsognathids, and one seperating it from coelurosaurs, and I have just started reading the paper. I'm not saying it is not possible that it was a coelurosaur, but it is not probable imo
Did Cau even have access to the specimens? I'm getting the impression the importance of a single matrix is sometimes overrated. It is a great project, but like any other analysis it can be wrong, in fact that wouldn't be too unusual as cladistic analyses nearly always contradict each other.
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theropod
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On the Concavenator-issue: Darren Naish just states he is not convinced of these being quill knobs, not that they couldn't be. With all due respect, I have the impression you are jumping to conclusions and believing every post that doubts the existence of megalosaurs or carnosaurs. That post is an interesting alternative indeed, still there are other sources that are not simply debunked once someone has doubts, even less if those sources are the ones actually studying and describing the real fossils (Darren Naish would certainly agree here, after all he states the exact same thing when explaining why Reptileevolution is BS).

These are not necessarily quill knobs, but they could be, Sciurumimus isn't necessarily a megalosauroid, but it could be and in boith cases there is no reason why they shouldn't, unless one doesn't like the tought of feathery integument being more widespred than tought.
Edited by theropod, Feb 11 2013, 04:24 AM.
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Jinfengopteryx
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theropod
Feb 11 2013, 04:14 AM
After all, Rauhut and collegues even give features that it differs from coelurosaurs in.
If you allow me, I can quote myself, to say why Rauhut claimed it was a Coelurosaur:
http://www.pnas.org/content/109/29/11746.full.pdf

The maxilla has a marked kink in the anterior margin of the ascending process dorsally and a large maxillary fenestra, which is closed medially (Figs. 1B and 2A), as in other megalosaurids (9, 10). A small premaxillary fenestra seems to be present under the overhanging anterior rim of the antorbital fossa. The maxillary antorbital fossa anterior to the antorbital fenestra accounts for ∼23% of the total length of the antorbital fossa, as in other basal tetanurans but unlike coelurosaurs, in which it typically accounts for 40% or more of the antorbital fossa (11). The lacrimal has a long, thin anterior process, which laterally forms a large lacrimal antorbital fossa that is continuous between the dorsal and ventral part of the vertical strut, in contrast to most theropods but similar to Torvosaurus (12).

His sources:
(9). Benson RBJ (2008) A redescription of ’Megalosaurus’ hesperis (Dinosauria, Theropoda) from the Inferior Oolite (Bajocian, Middle Jurassic) of Dorset, United Kingdom. Zootaxa 1931:57–67.
(10). Benson RBJ (2010) A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zool J Linn Soc 158:882–935.
http://onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.2009.00569.x/abstract
(11). Rauhut OWM (2003) The interrelationships and evolution of basal theropod dinosaurs. Spec Pap Palaeont 69:1–213.
(12). Britt BB (1991) Theropods of Dry Mesa Quarry (Morrison Formation, Late Jurassic), Colorado, with emphasis on the osteology of Torvosaurus tanneri. BYU Geol Stud 37:1–72.


Just to make clear, why it is believed to be a Megalosaur.
Here a family-tree:
Posted Image
I hope this should make clear the arguments, so that we have the arguments on both sides.
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JD-man
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theropod
Feb 11 2013, 04:14 AM
^I didn't write they wheren't, of course birds are saurischians, for the same reasons they are dinosaurs as you note yourself. Obviously, the ornithischian pelvis is a mere homoplasy. I think that fact is so obvious it can be regarded general knowledge. I'm just rejecting the claim that ornithischians where not birdlike, as I think all dinosaurs share many birdlike features.


Just making sure.

theropod
Feb 11 2013, 04:14 AM
I wouldn't say "probably", "maybe" or "possibly" would be more appropriate. After all, there is more to a cladistic analysis than the mere inclusion of lots of taxa (of course that's important), but weighing features is too important. I tend to trust human analyses in such regards, as no computer has so far given me an explanation why an animal should have megalosauroid features but be a coelurosaur.
After all, Rauhut and collegues even give features that it differs from coelurosaurs in.

I can count four traits that it shares with megalosaurs, countless ones that are similar to other basal tetanurans, one that it shares with compsognathids, and one seperating it from coelurosaurs, and I have just started reading the paper. I'm not saying it is not possible that it was a coelurosaur, but it is not probable imo
Did Cau even have access to the specimens? I'm getting the impression the importance of a single matrix is sometimes overrated. It is a great project, but like any other analysis it can be wrong, in fact that wouldn't be too unusual as cladistic analyses nearly always contradict each other.


theropod
Feb 11 2013, 04:23 AM
On the Concavenator-issue: Darren Naish just states he is not convinced of these being quill knobs, not that they couldn't be. With all due respect, I have the impression you are jumping to conclusions and believing every post that doubts the existence of megalosaurs or carnosaurs. That post is an interesting alternative indeed, still there are other sources that are not simply debunked once someone has doubts, even less if those sources are the ones actually studying and describing the real fossils (Darren Naish would certainly agree here, after all he states the exact same thing when explaining why Reptileevolution is BS).

These are not necessarily quill knobs, but they could be, Sciurumimus isn't necessarily a megalosauroid, but it could be and in boith cases there is no reason why they shouldn't, unless one doesn't like the tought of feathery integument being more widespred than tought.


1stly, I didn't deny the possibility that Sciurumimus was a megalosaur, but said that it was probably a coelurosaur, given the evidence (E.g. As Cau showed, the traits you listed are probably plesiomorphic tetanuran traits). Likewise, I didn't deny the possibility that Concavenator had proto-feathered arms, but said that it probably lacked them, given the evidence (E.g. As Naish showed, the structures of Concavenator are inconsistent w/the quill knobs of maniraptorans).

2ndly, while I may be overly cautious, you seem to be overly incautious in that, from the looks of it, you're jumping on every possibly feathered/proto-feathered fossil as evidence of feathers/proto-feathers in dinos ancestrally regardless of its validity (No offense, just saying). This is especially so when you say things like, "the normal state among dinosaurs is to be feathered".

BTW, it's worth mentioning that, contra the quoted phlogeny in my previous post, most phylogenies in recent years have recovered coelurids as tyrannosauroids & compsognathids as closer to birds than tyrannosauroids are (E.g. Senter 2007, Choiniere et al. 2010, Zanno & Makovicky 2010, etc.).
Edited by JD-man, Feb 12 2013, 01:49 PM.
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theropod
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the "probably" is what I was responding too, I think stating it was probable (=more likely than the other theories) basing on blog posts is too much.

No offense, I think you simply are too cautious. The whole reasoning seems to base on a stantpoint like "how can we explain that it had feathers even tough it isn't supposed to". I think the evidence feathers were ancestral to dinosaurs is very persuasive, not to say overwhelming, regardless of the exact anatomy and phylogeny in specimens like Sciuromimus or Concavenator. Those are merely further reinforcements, we have enough other evidence that deomstrate my points. Therefore it is by no means incautious to assume feathers, it is cautious.
Assuming they did not have them is incautious, since so far no real evidence exists against their presence in all of ornithodira, while there's plenty of it for filaments as plesiomorphic condition. The burden of proof is on those who claim those were NO filaments, not on those who say they are. You should turn around and view this from another perspective, filaments are the integument that should be automatically assumed and only doubted on the basis of hard evidence, not the other way around.
Edited by theropod, Jun 14 2013, 11:31 PM.
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SpinoInWonderland
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theropod
Feb 11 2013, 09:13 AM
filaments are the integument that should be automatically assumed and only doubted on the basis of hard evidence, not the other way around.
You still believe this so I can reply.

Well the answer for that is...


N O

SpinoInWonderland
Sep 21 2013, 02:59 AM
A new scenario for the evolutionary origin of hair, feather, and avian scales

"A few samples of the skin of dinosaurs which have been fossilized, consist of granulated scales, not overlapping scales (Gohlih & Chiappe, 2006). In my view it is not necessary to have overlapping scales to form feathers. More probably, feathers may have evolved from the tuberculate scales of the first archosaurs, possibly made of beta-keratins, and even more precisely of feather-type beta-keratins. Recent results (Dalla Valle et al. 2008) strongly suggest that feather beta-keratins originated deep in archosaur evolution, before the split between birds and crocodiles."

"The first archosaurs may have developed symmetrical tuberculate beta-keratinized scales, then, in theropod dinosaurs, the increase of the Wnt/beta-catenin pathway and the formation of dermal condensations, favored long proto-feather to develop, followed by the formation of branched structures, a rachis, barbules, and finally an asymmetry developed in the vane, as in modern feathers."

Posted Image

Tuberculate scales came first. The feather thing was only applied to theropods. And to take this further, all known feathers were found only in Coelurosauria. For all other dinosaurs, we only get tuberculate scales and quills.

And after all this time, you have yet to provide evidence of pterosaur pycnofibres being homologous to coelurosaurian feathers.
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