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| Extinct Animal Questions | |
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| Topic Started: Nov 26 2013, 10:24 PM (193,294 Views) | |
| Paleop | Apr 30 2016, 10:42 AM Post #3001 |
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Paleopterix
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could Plateosaurids have had feathers? (I assume they are more basal) |
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| Incinerox | Apr 30 2016, 11:43 AM Post #3002 |
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Āeksiot Zaldrīzoti
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Such an answer really depends on who you ask. I would say no, on the basis that all sauropod skin and all known basal theropod skin were scaly, therefore indicating the common ancestor between both saurischian clades was scaly too. This would put prosauropods well within the realms of being scaly. Someone else might throw in basal ornithischians into the fray and say that the basal saurischian must've been fluffy, and subsequently lost them, meaning that prosauropods had a chance at being fluffy too. I personally think for this question, ornithischians are irrelevant to this particular connundrum (because of the more compelling data from Plateosaurus's more immediately surrounding clades), making this point moot. |
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| heliosphoros | Apr 30 2016, 08:36 PM Post #3003 |
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Considering the amount of non-footprint non-ceratosaurian and non-coelurosaur theropod integrument is virtually zero, not at all. Currently, all evidence points to an ancestrally fluffy Archosauria. |
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| Incinerox | May 1 2016, 01:04 AM Post #3004 |
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Āeksiot Zaldrīzoti
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> Shoots down an argument discussing a very specific point in dinosaur evolution, on the basis that evidence available to test either option is virtually zero. > We have MORE than enough data to conclude the ancestral integument for ALL archosaurs. How can you possibly make this claim? We can't even confirm whether or not pycnofibres and feathers are the same yet. Until we do that, we can't even confirm what the basal ornithodiran had, let alone the ancestor of all god damn archosaurs. > Basal theropod - unknown. Most basal theropod with skin data is Carnotaurus, which was covered in small scales, with rows of osteoderms. > Basal sauropod - unknown. However all derived sauropods were covered fully in small scales, some with osteoderms. > Basal saurischian - unkown. See ^^^ > Basal ornithischian - unknown. The entire clade is a cluster**** of scales and fluff (which we can't even pin down as true feathers yet). However, they are prone to mixing together multiple types of integument. > Basal dinosaur - unknown. Without confirmation from either ornithischian or saurischian integument, this statement is impossible to make. > Basal pterosaur - unknown. All derived pterosaurs have pycnofibres, which we cannot confirm are the same as feathers. > Basal ornithodiran - unknown. Without data for basal dinosaurs or pterosaurs, this statement is impossible to confirm. If it turns out pycnofibres ARE in fact feathers (pro tip: cannot confirm), we might have something to work with. > Basal curotarsan - scaly. Literally every clade within the curotarsi is known to be covered in scales or osteoderms, even the basal most clade within it, the phytosaurs. Interesting point to be made here is that such "scales" have feather genes encoded within. > Basal archosaur - Unknown. Between having one clade being known to be scaly through and through, and the other being a cluster**** of scales, and potentially multiple types of fluff, we cannot say for sure what the answer is. But even if it turns out that the basal ornithodiran was fluffy, and the whole clade was fluffy, that still leaves a 50/50 possibility for the basal archosaur. So the point that "all evidence" suggests a fluffy basal archosaur is... An outright lie. The supposed evidence is literally a list of complete unknowns and unconfirmed statements. We can't even pin down the integument of basal dinosauromorphs, yet apparently it's enough to confirm what the base condition for EVERYTHING was? However, I've made a point before that there is one type of integument that is known across ALL archosaurs, which fits everything from theropods, derived sauropods, hadrosaurs, basal ornithischians, pterosaurs, crocodilians and stuff, integument that would explain the genes for feathers within modern crocs without an entire clade ever expressing it even once, while its sister clade took it and went MAD with it. Reticulae. The basal archosaur, in my reasonably educated and well read opinion, was covered in them small "scales" you see time and time again across all archosaurs. They have within them the genes for feathers without necessarily BEING feathers. And while never actually becoming fluff among curotarsans, instead evolving to just be larger, more "armored" scales seen in modern crocs, it would explain why modern crocodilians have that gene. Such integument would make an ideal foundation for feather development in ornithodirans, whether feathers or pycnofibres were the same or otherwise. Honestly if we're dealing with cluster****s and unknowns, it's the best available compromise. So all evidence, my arse. If you have further issues, would you like to start another topic for this? It seems to be a regularly occurring point of contention within the paleontological section, and I'd rather not derail this topic further. Edited by Incinerox, May 1 2016, 06:07 AM.
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| heliosphoros | May 1 2016, 04:51 PM Post #3005 |
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As discussed before, reticulae are proven to be stunted feathers. There's no observable other means to get reticulae. Ergo, under YOUR logic, it implies feathers were prevalent across archosaurs, since reticulae had to evove from feathers |
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| Paleop | May 1 2016, 10:02 PM Post #3006 |
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Paleopterix
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http://thezt2roundtable.com/topic/11596317/2/#new *ahem* there is the debate topic....
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| Acinonyx Jubatus | May 1 2016, 10:13 PM Post #3007 |
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I AM THE UNSHRINKWRAPPER!
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I can't access it. The palaeo group disappeared for me for some reason. Can you fix it? |
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| Yi Qi | May 1 2016, 10:53 PM Post #3008 |
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Iirc it was a permission mask problem, try rejoining it and if it doesn't work pm me and i'll fix your permissions myself. Edited by Yi Qi, May 1 2016, 11:17 PM.
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| stargatedalek | May 2 2016, 09:54 AM Post #3009 |
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I'm not slow! That's just my moe!
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While I disagree with his final conclusions, Incinerox is correct that there simply isn't enough evidence to truly claim with certainty that soft integument is basal to archosauria, let alone that that soft integument is directly related to the various forms found throughout the group. |
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| CyborgIguana | May 3 2016, 03:08 PM Post #3010 |
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Read in a Facebook comment recently from a guy who claimed to be a geologist that radiometric dating is (to a certain extent) unreliable because there's a chance that some of the decay products were building up after the initial formation of the isotope rather than having been there from the start. I doubt this is true, of course, but can anyone here confirm?
Edited by CyborgIguana, May 3 2016, 06:00 PM.
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| BossMan, Jake | May 4 2016, 10:38 AM Post #3011 |
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Son of God
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Would camptosaurus have walked on all fours like an Iguanadont or bipedaly like dryosaurus? |
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| babehunter1324 | May 4 2016, 12:24 PM Post #3012 |
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I recall Scott Hartman wondering the same thing. I think he came to the conclusion that Camptosaurus was probably uncapable to move for extended periods of time using it's four limbs, their forelimbs were stocky but pretty short and completelly suppinated.![]() That said I still found likely that Camptosaurus would be able to stand quadrupedally while browsing on low vegetation. Edited by babehunter1324, May 4 2016, 12:29 PM.
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| Incinerox | May 4 2016, 01:37 PM Post #3013 |
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Āeksiot Zaldrīzoti
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A paper on Tenontosaurus, which was noted to be a very good analogue for camptosaurids, basically confirmed that they were obligate bipeds. It's likely the same rules for Tenontosaurus applied to Camptosaurus. |
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| BossMan, Jake | May 4 2016, 02:19 PM Post #3014 |
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Son of God
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Huh never would've thought they were restricted to their back legs, interesting! thank you |
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| Acinonyx Jubatus | May 4 2016, 03:08 PM Post #3015 |
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I AM THE UNSHRINKWRAPPER!
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So I understand Dimetrodon's spines were figure-8 shaped in cross-section, with a groove running down each side. I believe it was said that this structure strengthened the spine and prevented bending. What I want to know is, in which planes were bending restricted? Would it have been rather flexible from side-to-side and stiff front-and-back, or stiff all 'round? And would the groove have housed some sort of soft tissue or vascularization? Actually, does anyone have a complete, detailed diagram of an entire Dimetrodon vertebra, including the spine? |
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