tag:blogger.com,1999:blog-3049195237412585561.post2295987904318468156..comments2023-11-07T12:07:59.585-08:00Comments on Pterosaurs to Birds: Evolution of Feathers Unknownnoreply@blogger.comBlogger15125tag:blogger.com,1999:blog-3049195237412585561.post-91332717108625460662017-03-04T12:56:07.094-08:002017-03-04T12:56:07.094-08:00I am glad you like it. Care to contribute?I am glad you like it. Care to contribute?Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-79073836974110723402017-01-04T06:17:31.613-08:002017-01-04T06:17:31.613-08:00https://pterosaur.net/ecology.php
The fibrolamella...https://pterosaur.net/ecology.php<br />The fibrolamellar texture of pterosaur bone suggests that they had high metabolic rates akin to those of birds and mammals and were therefore capable of rapid growth, but size distributions clusters of single pterosaur species (notably those of the Jurassic form Rhamphorhynchus) suggest their growth rate was low: Rhamphorhynchus may have taken several years to achieve its full size (Fig. 1). This is quite unlike the growth rates of the metabolically supercharged birds and mammals, so what gives? Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-59777638966784838842016-12-27T08:37:53.973-08:002016-12-27T08:37:53.973-08:00http://www.nature.com/articles/srep14864
Particula...http://www.nature.com/articles/srep14864<br />Particularly remarkable is the [Enantiornithes] presence of an almost completely preserved postpatagium, extending from the caudoproximal base of the ungual phalanx of digit II to the preserved proximal-most caudal portion of the ulna and in clear association with the wing’s plumage (Fig. 1). The preserved calami of flight feathers (i.e., primaries and secondaries) are embedded in the postpatagium, forming the same sinuous caudal outline visible in the naked (i.e., unfeathered) wing of modern birds10,17Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-32215665141452601932016-12-27T08:12:34.590-08:002016-12-27T08:12:34.590-08:00Similarities:
Actinofibril and feather rachis
Pata...Similarities:<br />Actinofibril and feather rachis<br />Patagium<br />Multiple layers and overlapping feathersDr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-87427070213066350872016-12-18T07:44:31.845-08:002016-12-18T07:44:31.845-08:00https://pterosaur.net/restoration.php
Many fossils...https://pterosaur.net/restoration.php<br />Many fossils also preserve hair-like integument, which is often called "ptero-fuzz". Ptero-fuzz varied from coarse to fine, and seems to have been extensive in at least some pterosaurs. The fuzz may have been dry and truly "fuzzy" as in bats, or it may have been kept oily and slicked, as bird feathers. Certainly have an oily coat would have helped prevent fishing pterosaurs from getting water-logged if they came in contact with the water.<br />Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-39483124830071446952016-12-17T08:55:39.301-08:002016-12-17T08:55:39.301-08:00
A very important perception of the pterosaur wing...<br />A very important perception of the pterosaur wing membrane is that it is a set of fibres (actinofibrils) which are joined together by a skin membrane.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-54699243922981754192016-12-16T14:48:08.947-08:002016-12-16T14:48:08.947-08:00http://ncsce.org/pages/feathers.html
Although a fe...http://ncsce.org/pages/feathers.html<br />Although a feather resembles a tree (with a trunk sprouting branches and smaller branches sprouting from those branches), the way a feather grows is quite different from the way a tree grows. Feather growth is more akin to the story of the way a sculptor produces a figure from a block of marble - the statue of David was already in the rock, Michelangelo simply removed anything that wasn't David. Similarly, a feather does not start as a shaft which sprouts branches, it begins as a tapered cylinder and cell-death creates the structures.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-90161626895650098402016-12-16T14:26:58.525-08:002016-12-16T14:26:58.525-08:00https://academy.allaboutbirds.org/feathers-article...https://academy.allaboutbirds.org/feathers-article/2/<br />The wing feathers specialized for flight are characterized by uniform windproof surfaces, or vanes, on either side of the central shaft that are created by an interlocking microstructure. Also called remiges<br />, these feathers are asymmetric with a shorter, less flexible leading edge that prevents midair twisting.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-45255738075396770022016-12-16T12:55:43.537-08:002016-12-16T12:55:43.537-08:00http://www.theodora.com/encyclopedia/f/feather.htm...http://www.theodora.com/encyclopedia/f/feather.html<br />c, Two barbules of the posterior series - seen only in crosssection in b. The rods comprising the lateral fringe, or vane, are known as the rami or the " barbs," and will be found, on microscopic examination, to be lath-shaped and to taper to a point. Further, each barb supports a double series of smaller outgrowths known as the radii, or "barbules "; so that each barb may be likened to a feather in miniature. These " barbules," however, differ markedly in structure on the two sides of the barb, those pointing towards the tip of the feather - the " anterior barbules " - being ribbon-shaped from the base outwards for about half their length, when they become cut up to form a series of long and very delicate hooklets (fig. I'd). On the opposite side of the barb the barbules are also ribbon-shaped for about half their length, but the ribbon is curved trough-fashion, so that the whole series of posterior barbules forms a number of deep valleys, and into these the 'hooklets are thrust so as to catch hold of the upper edges of the troughs, which are set so that the f, Feather-Barbs.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-52357357348562171742016-12-16T09:51:21.132-08:002016-12-16T09:51:21.132-08:00https://archosaurmusings.wordpress.com/2009/08/05/...https://archosaurmusings.wordpress.com/2009/08/05/what-on-earth-are-pycnofibers/<br />However being, well, pterosaurs one could hardly call their ‘fur’ fur, or hair for that matter, these being the preserve of synapsids (and by extensions, mammals). Nor (despite some calls for it) could they be considered protofeathers as there is no established homology between them and saurischian protofeathers and feathers (or for that matter ornithischian dermal structures). This has left pterosaur researchers with a problem – these are clearly different things and we refer to the quite often but with no-one having gone out onto a limb and named them, we were left with a variety of half-names all of them convoluted or presented in quotation marks.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-82619836133183144882016-12-16T09:47:18.821-08:002016-12-16T09:47:18.821-08:00https://archosaurmusings.wordpress.com/2008/06/16/...https://archosaurmusings.wordpress.com/2008/06/16/pterosaur-wings-2-structure/<br />Actinofibrils are unusual structures and we are not sure exactly what they are composed of. The best guess is collagen, but it could also be cartilage or keratin. Determining this in fossils is obviously near impossible but all three are realistic possibilities, though of course collagen is the most likely given the position of the fibres inside the wing membrane (rather than on the surface) and they do not connect to the bones of the wing finger. They lie sub-parallel to the wing towards the wingtips and then sub-perpendicular as we move more proximally. There are no actinofibrils in the proximal wing close to the body, and they get more densely packed the further away you go.<br />Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-51420353820219965712016-12-16T08:39:08.763-08:002016-12-16T08:39:08.763-08:00hooklet = barbicel = hamuli
hooklet = barbicel = hamuli<br />Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-29168980469811002362016-12-16T08:29:15.182-08:002016-12-16T08:29:15.182-08:00http://prumlab.yale.edu/sites/default/files/prum_1...http://prumlab.yale.edu/sites/default/files/prum_1999_mde_development.pdf<br />Avian bristles are characterized by the increased<br />strength of the rachis and the reduction (sometimes<br />complete) of the barbs and barbules. Bristles<br />evolved through the derived reduction in barb<br />number and barbule structure within the follicle<br />(stage Vf).Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-45012319753015137872016-12-12T08:53:22.325-08:002016-12-12T08:53:22.325-08:00https://bio.unc.edu/files/2011/04/FeducciaCzerkas2...https://bio.unc.edu/files/2011/04/FeducciaCzerkas2015.pdf<br />We focus here on the discovery of an anatomical feature,<br />the propatagium, which argues that Caudipteryx<br />supports the neoflightless hypothesis—that is, it is derived<br />from a flighted ancestry (Paul 2002)—and therefore its<br />highly derived avian anatomy was selected for in an<br />aerodynamic context.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-40127995335586028682016-12-12T07:27:04.128-08:002016-12-12T07:27:04.128-08:00
https://archosaurmusings.wordpress.com/2009/08/05...<br />https://archosaurmusings.wordpress.com/2009/08/05/what-on-earth-are-pycnofibers/<br />David Hone<br />03/11/2010 at 3:19 pm<br />Yes, that’s a typo. It should of course read more as “….keratin, like scales, feather and hair”.<br />Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.com