tag:blogger.com,1999:blog-3653345901774701895.post5226425360628808923..comments2024-03-23T12:02:36.626-07:00Comments on Mark P. Witton's Blog: What pterosaurs tell us about the evolution of feathersMark Wittonhttp://www.blogger.com/profile/02524696111911168322noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-3653345901774701895.post-67650212516073705952016-07-21T01:01:09.423-07:002016-07-21T01:01:09.423-07:00What kind of integuments that Tyrannosaurs have? I...What kind of integuments that Tyrannosaurs have? Is it plumulaceous feathers like what the Chinese paleontologists guess about Yutyrannus or is it simple filaments with no branches or calamus that distributed individually like mammalian hairs? By looking at the integuments on Dilong, I doubt it look like down feathers because it look more similar like individual hairs that are clumped into one.Dobbyhttps://www.blogger.com/profile/11330841767766793540noreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-47794482148016460122015-10-10T14:45:53.388-07:002015-10-10T14:45:53.388-07:00Dinosaurs had bristles.Dinosaurs had bristles.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-57735103709227183112015-10-08T06:49:58.475-07:002015-10-08T06:49:58.475-07:00Thanks for the reply.
My comment about filling bl...Thanks for the reply.<br /><br />My comment about filling blanks with proto-feathers concerned your skepticism of Scleromochlus being scaly, not Barret et al.'s study per se.<br /><br />I enjoyed your analysis, but it gave me the impression that you're holding onto every little bit of doubt concerning the suggestion that pterosaur ancestors might have been scaly just to tip the model towards the interpretation you prefer, based on your "leaning".Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-52128580628107074932015-10-07T09:19:24.901-07:002015-10-07T09:19:24.901-07:00I think you're missing the point of the Barret...I think you're missing the point of the Barrett et al. study, which was testing the probability of filaments or scales occurring in the ancestors of ornithodiran clades. No-one 'poured proto-feathers into all gaps in existing data': they used current data to see what integument types were likely for different stages of ornithodiran evolution. <br /><br />"what would happen if you extended the model a further 50 million years back to include more lineages like crocodilians, saurischians, and ultimately *mammals* as well (assuming mammal hair=proto-feathers)?"<br /><br />Given that we have heaps of scaly animals between ornithodirans and mammals on the amniote tree, I'm not sure this would tell us anything. There's no evidence for filaments on the reptile lineage until we get to Ornithodira, which is why (I guess) the Barrett et al. study focused on this group alone. Mark Wittonhttps://www.blogger.com/profile/02524696111911168322noreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-82653722352504199772015-10-07T09:11:11.498-07:002015-10-07T09:11:11.498-07:00Thanks for the comment, Andrew. I guess the whole ...Thanks for the comment, Andrew. I guess the whole point of the Barrett et al. study was to determine the likelihood of that hypothesis. If the ornithodiran ancestor was scaly, then, yes, we might assume that there was genetic predilection for developing fuzziness in each ornithodiran lineage (as in, it was 'easy' for them to do it, which is why it developed multiple times). Mark Wittonhttps://www.blogger.com/profile/02524696111911168322noreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-7548227824900169612015-10-03T12:35:20.026-07:002015-10-03T12:35:20.026-07:00I think it's important also to know if the all...I think it's important also to know if the alligator "feather genes" are actually correlated to filemental integrument. If they are, then it makes it unambiguous that Archosauria started as possessing "feathers"Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-82951505870236640682015-09-28T10:43:41.296-07:002015-09-28T10:43:41.296-07:00This comment has been removed by the author.Anonymoushttps://www.blogger.com/profile/13191273397897104786noreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-26490823158699615732015-09-28T10:35:05.830-07:002015-09-28T10:35:05.830-07:00This comment has been removed by the author.Anonymoushttps://www.blogger.com/profile/13191273397897104786noreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-20431135596588596912015-09-27T08:24:11.210-07:002015-09-27T08:24:11.210-07:00Oops, one correction: I meant possibly extending t...Oops, one correction: I meant possibly extending the model to include 'lepidosauria', not 'saurischians'. Damn all those pesky lizard-derived names.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-39472926794632135762015-09-26T06:48:11.243-07:002015-09-26T06:48:11.243-07:00Perhaps I've been reading too much Reptipage, ...Perhaps I've been reading too much Reptipage, but your post's main argument for feathered ornithodirans sounds a bit like you're instantly pouring proto-feathers into all gaps in existing data. Both hypotheses are likely at this point, but it doesn't translate into both being equally likely - to be honest, this concerns everything when it comes to reconstructing extinct animals.<br /><br />I can't access full data from Barret et al. 2015, but what would happen if you extended the model a further 50 million years back to include more lineages like crocodilians, saurischians, and ultimately *mammals* as well (assuming mammal hair=proto-feathers)? Y'know, just as control factors. We know that diverse lineages can, and do, undergo changes filamentary structures at much shorter timescales than the one involved here: turkey beards, pangolin scales, etc.<br /><br />Regardless of all that, I think Andrew Raymond Stück raises a good point. Organisms inherit genes, not features. Perhaps the crucial genes responsible for the diversity of integumentary structures in dinosaurs and pterosaurs can indeed be traced back to ornithodiran or archosaur clades, but that'd mean something different than saying they inherited the same phenotypical structures. The distinction between scales & feathers was a big leap, but so was the leap between different stages of feathers, and unless I'm mistaken, both ornitischians and coelulosaurids show evidence of "stage 2"-style feathers. Personally, I wouldn't treat is at evidence for proto-branching-feathers in their last common ancestor, not any more than evidence for proto-wings in the last common ancestor of pterosaurs, bats and birds...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-23831531848798737822015-09-25T12:38:45.383-07:002015-09-25T12:38:45.383-07:00Isn't Archosauria fuzzy ancestrally?Isn't Archosauria fuzzy ancestrally?BKhttps://www.blogger.com/profile/03759189747932749283noreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-49177062103383525992015-09-25T10:06:10.249-07:002015-09-25T10:06:10.249-07:00Is it possible that Ornithodira could be basally s...Is it possible that Ornithodira could be basally scaly but with strong genetic traits that make the independent evolution of filaments very easy? To put it another way, perhaps these lineages may have independently expressed pre-existing genes, but did not independently evolve them.Andrew Raymond Stückhttps://www.blogger.com/profile/12080621275951453768noreply@blogger.comtag:blogger.com,1999:blog-3653345901774701895.post-66846920309441209102015-09-25T07:14:28.101-07:002015-09-25T07:14:28.101-07:00Very intersting article, a real pitty that the fos...Very intersting article, a real pitty that the fossil record is so incomplete, well... Maybe be will one day get lucky and found deffinitive proof of the intergument cover of basal Ornithodirans.Anonymoushttps://www.blogger.com/profile/14164538558433319744noreply@blogger.com