[75] This behavior is seen in numerous bird species; parent birds regurgitate food into the hatchling's mouth. Each of the feathered dinosaur families developed avian-like features in its own way. Shortly after the 1859 publication of Charles Darwin's The Origin of Species, the ground-breaking book which described his theory of evolution by natural selection,[1] British biologist and evolution-defender Thomas Henry Huxley proposed that birds were descendants of dinosaurs. Its name literally means “fear nothing,” and it is thought that the immense size of this herbivore left it with few—if any—predators as an adult. It was originally conceived of by paleornithologist Alan Feduccia. [76] In the Jehol Biota in China, various dinosaur fossils have been discovered that have a variety of different tooth morphologies, in respect to this evolutionary trend. The filaments are arranged in a parallel fashion to each other, and are perpendicular to the bones. It was probably an active bipedal predator, hunting with the large sickle-shaped claw on the second toe of each hind foot. Due to this discovery, paleontologists are now convinced that beta-keratin-based protofeathers had evolved at the base of this clade at least. The known fossil record of these groups is highlighted. [177] NGMC 91-A, the Sinornithosaurus-like theropod informally dubbed "Dave", possessed unbranched fibers in additional to more complex branched and tufted structures. During the early decades of the 20th century the idea of tree-climbing dinosaurs became reasonably popular as Othenio Abel, Gerhard Heilmann and others used comparisons with birds, tree kangaroos and monkeys to argue that the small ornithopod Hypsilophodon (also from the Wessex Formation of the Isle of Wight) was scansorial. Unlike most other saurischian dinosaurs, which have pubic bones that point forward, several groups of maniraptorans have an ornithischian-like backwards-pointing hip bone. Fossil of Sinornithosaurus millenii, the first evidence of feathers in dromaeosaurids. Over one hundred distinct anatomical features are shared by birds and theropod dinosaurs. Skin impressions from the type specimen of Beipiaosaurus inexpectus indicated that the body was covered predominately by downy feather-like fibers, similar to those of Sinosauropteryx, but longer, and are oriented perpendicular to the arm. The author very much agrees with Chiappe in arguing that at present, Protoavis is irrelevant to the phylogenetic reconstruction of Aves. [30] Similarly, structures in the fossil record composed of a series of filaments joined at their bases along a central filament bear an uncanny resemblance to the down feathers in modern birds, with the exception of a lack of barbules. Birds – the only surviving lineage of dinosaurs – are covered in plumage. Lawrence Witmer stated: However, not all scientists agreed that Caudipteryx was unambiguously non-avian, and some of them continued to doubt that general consensus. "Minute theropod eggs and embryo from the Lower Cretaceous of Thailand and the dinosaur-bird transition. Sinotyrannus - This "Chinese tyrant" was an ancient ancestor of tyrannosaurs. (2005) argued that Pelecanimimus possessed scaly arms and figured some unusual rhomboidal structures in an effort to demonstrate this. The birds came first: a scenario for avian origins and early evolution. A recent development in the debate centers around the discovery of impressions of "protofeathers" surrounding many dinosaur fossils. The "Birds Came First" hypothesis of bird and dinosaur evolution. [199] They also appear to be relatively rigid, making them more analogous to the integumentary structures found on the tail of Psittacosaurus[95] than to the proto-feather structures found in avian and non-avian theropods. So this strongly suggests that all dinosaurs had feathers. The birds came first: a scenario for avian origins and early evolution, 1. By the 25th tail vertebrae, the filaments on the underside reach a length of only 35 mm. Both show evidence of integumentary structures. Birds were originally linked with other dinosaurs back in the late 1800s, most famously by Thomas Huxley. Norell et al (2007) reported quill knobs from an ulna of Velociraptor mongoliensis, and these are strongly correlated with large and well-developed secondary feathers.[178]. The scarcity of maniraptoran fossils from this time is not surprising, since fossilization is a rare event requiring special circumstances and fossils may never be found of animals in sediments from ages that they actually inhabited. Velociraptor. (, Ruben, J., Dal Sasso, C., Geist, N. R., Hillenius, W. J., Jones, T. D. & Signore, M. (, Ruben, J., Hillenius, W., Geist, N. R., Leitch, A., Jones, T. D., Currie, P. J., Horner, J. R. & Espe, G. (, Zhou, Zhonghe, Clarke, Julia A., Zhang, Fucheng. Anchiornis has hind leg proportions more like those of lower theropod dinosaurs than avialans. [141] The development of avian characteristics in dinosaurs supposedly should have led to the first modern bird appearing about 60 million years ago. Furthermore, even though crocodilians and dinosaurs are fundamentally different in pelvic anatomy, some living birds have the key soft-tissue traits reported by Ruben et al. [119][120][42] Embryological studies of bird developmental biology have raised questions about digit homology in bird and dinosaur forelimbs. And, if you read it, it only has one syllable. Fossil feathers were unheard of at the time, yet somebody had pulled one out of a limestone quarry near Solnhofen, Bavaria. [30], The functional view on the evolution of feathers has traditionally focussed on insulation, flight and display. Enjoy! [16][17] George was aware of this fact, and apparently considered the rather tongue-in-cheek alternative acronym GOODD, meaning George Olshevsky On Dinosaur Descendants. [168] The estimated length of the integumentary structures on the tail is about 60 mm which is seven times the height of a caudal vertebra. The Berlin Archaeopteryx specimen appears to preserve such structures on the back of the neck though pennaceous vaned feathers were present on its back, at least. The consensus view is that birds evolved from dinosaurs, but the most bird-like dinosaurs, and those most closely related to birds (the maniraptorans), are known mostly from the Cretaceous, by which time birds had already evolved and diversified. [85], Feathers are extremely complex integumentary structures that characterize a handful of vertebrate animals. Maniraptorans possessed vaned feathers with barbs, barbules and hooklets just like those of modern birds. On Microraptor, the long feathers on the forelimbs possess asymmetrical vanes. Several specimens of Microraptor, described by Xu et al. [181] Xu and Zhang, in their 2005 description of Pedopenna, suggested that the feathers could be ornamental, or even vestigial. ‘They were found only in one group - the theropod group closest to birds, the Coelurosauria’. Illustration of a feathered Velociraptor making a trackway. [105] Feathered hands would also have restricted the ability of the hands to pick objects off of the ground, given that the feathers extend well beyond the ends of the digits. In Prum's model of feather evolution, hollow quill-like integumentary structures of this sort were termed Stage 1 feathers. This has led some paleontologists, such as Xu Xing, to theorize that feathers share homology with lizard scales after all. No surprise there. These bumps on bird wing bones show where feathers anchor, and their presence on Velociraptor indicate it too had feathers. Furthermore, structures on fossils have been recovered from Chinese Cretaceous deposits that are a series of filaments joined at their bases at the distal portion of the central filament bear a superficial resemblance to filoplumes. In 1964, the first specimen of Deinonychus antirrhopus[5] was discovered in Montana, and in 1969, John Ostrom of Yale University described Deinonychus as a theropod whose skeletal resemblance to birds seemed unmistakable. Medullary bone has been found in specimens of sub-adult size, which suggests that dinosaurs reached sexual maturity rather quickly for such large animals. Since the 1990s, a number of additional feathered dinosaurs have been found, providing even stronger evidence of the close relationship between dinosaurs and modern birds. The species was discovered by scientists including Mark Norell and Phil Currie, and was named for Zou Jiahua, a high-ranking Chinese official and a supporter of the palaeontological work at Liaoning. [189] Similarly, quill knobs (anchor points for wing feathers on the ulna) have been reported in the oviraptorosaurian species, Avimimus portentosus. Posterior caudal vertebrate fused to form the. Fossil feather impressions are extremely rare; therefore only a few feathered dinosaurs have been identified so far. However, they do not have the secondary branching and tiny little hooks (barbules) that modern feathers have, which allow the feathers of modern birds to form a discrete vane. [Note 2] Some of the more interesting and notable similarities are discussed here: Archaeopteryx, the first good example of a "feathered dinosaur", was discovered in 1861. All specimens of Sinosauropteryx preserve integumentary structures (filaments arising from the skin) which most paleontologists interpret as very primitive feathers. The idea of scansoriality in non-avian dinosaurs has been considered a 'fringe' idea, and it's partly for this reason that, prior to 2000, nobody had attempted any sort of review on the thoughts that had been published about the subject. It has been argued that respiratory turbinates supposedly falsify dinosaur endothermy,[151] even though it has never been demonstrated that respiratory turbinates really are a requirement for any given physiological regime, and even though there are endotherms that lack respiratory turbinates. Similarly to down feathers of modern birds, the "protofeathers" found in Dilong were branched but not pennaceous, and may have been used for insulation.[38]. Three of the furculae are articulated in juvenile skeletons; two of these are missing fragments but are nearly complete, and one is apparently complete. [37], Thick, stiff, spine-like structures were recovered sprouting from the new specimen's throat region, the back of its head, its neck and its back. The EBFFs differ from other feather types in that they consist of a single, unbranched filament. Heilmann argued that birds could not have descended from dinosaurs (predominantly because dinosaurs lacked clavicles, or so he thought), and he therefore favored the idea that birds originated from the so-called 'pseudosuchians': primitive archosaurs that were also thought ancestral to dinosaurs and crocodilians. [149][150] The paper never really demonstrate anything, but merely try to shoot holes in a given line of supporting evidence. digit homology in bird and dinosaur forelimbs, #List of dinosaur genera preserved with evidence of feathers, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, http://darwin-online.org.uk/content/frameset?itemID=F373&viewtype=side&pageseq=16, Cretaceous age for the feathered dinosaurs of Liaoning, China, Further support for a Cretaceous age for the feathered-dinosaur beds of Liaoning, China: %u2026, http://www.springerlink.com/index/W7724740N2320M80.pdf, http://www.sciencenews.org/view/generic/id/94/title/All_mixed_up_over_birds_and_dinosaurs, Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids, Feathered Dinosaurs and the Origin of Flight: The Dinosaur Museum Journal 1, Important features of the dromaeosaurid skeleton II: Information from newly collected specimens of, THE FURCULA IN SUCHOMIMUS TENERENSIS AND TYRANNOSAURUS REX (DINOSAURIA: THEROPODA: TETANURAE), http://jpaleontol.geoscienceworld.org/cgi/content/extract/81/6/1523, http://www.redorbit.com/news/health/1139122/the_furcula_in_suchomimus_tenerensis_and_tyrannosaurus_rex_dinosauria_theropoda/index.html, 10.1671/0272-4634(2005)025[0835:NIOSHA]2.0.CO;2, http://web.archive.org/web/20060512053601/http://www.rvc.ac.uk/AboutUs/Staff/jhutchinson/documents/JH18.pdf, 10.1671/0272-4634(2005)025[0466:FCITPD]2.0.CO;2, Furculae in the Late Triassic theropod dinosaur, Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina, http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0003303, Meat-Eating Dinosaur from Argentina Had Bird-Like Breathing System, Gender-specific reproductive tissue in ratites and, http://www.sciencemag.org/cgi/content/abstract/308/5727/1456, Sexual maturity in growing dinosaurs does not fit reptilian growth models, http://www.pnas.org/cgi/content/abstract/105/2/582, A theropod dinosaur embryo and the affinities of the Flaming Cliffs Dinosaur eggs, http://www.sciencemag.org/cgi/content/abstract/266/5186/779, Thermal environments of dinosaur nestlings: Implications for endothermy and insulation, Society of Avian Paleontology and Evolution, Phylogenetic context for the origin of feathers, http://icb.oxfordjournals.org/cgi/content/abstract/40/4/486, http://news.bbc.co.uk/2/hi/science/nature/7684796.stm, Epidexipteryx: bizarre little strap-feathered maniraptoran, Chatterjee's Chimera: A Cold Look at the Protoavis Controversy, Velociraptorine dromaeosaurid teeth from the Kimmeridgian (Late Jurassic) of Germany, http://www.bhbfonline.org/AboutUs/Lori.pdf, Discovery Raises New Doubts About Dinosaur-bird Links, Feathered Dragons: Studies on the Transition from Dinosaurs to Birds, Access : Bald dino casts doubt on feather theory : Nature News, "Transcript: The Dinosaur that Fooled the World", http://www.bbc.co.uk/science/horizon/2001/dinofooltrans.shtml, Dino Hoax Was Mainly Made of Ancient Bird, Study Says, http://news.nationalgeographic.com/news/2002/11/1120_021120_raptor.html, Glorified Dinosaurs: The Origin and Early Evolution of Birds, 10.1206/0003-0082(2007)3557[1:ASDTFS]2.0.CO;2, http://www.foxnews.com/story/0,2933,479875,00.html, The fossil record of feather evolution in the Mesozoic, 10.1668/0003-1569(2000)040[0687:TFROFE]2.0.CO;2, http://www.bioone.org/perlserv/?request=get-abstract&doi=10.1668%2F0003-1569%282000%29040%5B0687%3ATFROFE%5D2.0.CO%3B2, T. rex was fierce, yes, but feathered, too, http://www.sciencemag.org/cgi/reprint/317/5845/1721.pdf, http://www.sciencedaily.com/releases/2007/09/070920145402.htm, A basal dromaeosaurid and size evolution preceding avian flight, http://www.sciencemag.org/cgi/reprint/317/5843/1378.pdf, Evo-Devo of feathers and scales: building complex epithelial appendages, http://www.nature.com/nature/journal/v458/n7236/full/458293a.html, http://scienceblogs.com/pharyngula/2009/03/tianyulong.php, "Tianyulong - a fuzzy dinosaur that makes the origin of feathers fuzzier", http://scienceblogs.com/notrocketscience/2009/03/tianyulong_-_a_fuzzy_dinosaur_that_makes_the_origin_of_feath.php, http://app.pan.pl/article/item/app47-097.html, http://www.mapress.com/zootaxa/2007f/z01582p017f.pdf, Feathered dinosaurs, flying dinosaurs, crown dinosaurs, and the name" Aves, Feathers and'feather-like'integumentary structures in Liaoning birds and dinosaurs, The origin and early evolution of birds: discoveries, disputes, and perspectives from fossil evidence, Birds have dinosaur wings: the molecular evidence, Why ornithologists should care about the theropod origin of birds, Cladistic approaches to the relationships of birds to other theropod dinosaurs, Mesozoic birds, above the heads of the dinosaurs, The early evolution of feathers: fossil evidence from Cretaceous amber of France, First Dinosaur Found With its Body Covering Intact; Displays Primitive Feathers From Head to Tail, Notes from recent papers on theropod dinosaurs and early avians, https://fossil.fandom.com/wiki/Feathered_dinosaurs?oldid=30976. Teeth with a constriction between the root and the crown. His claim made National Geographic review their research and they too came to the same conclusion. A recent analysis showed the presence of a very bird-like lung system in predatory dinosaurs. In September 2007, Alan Turner, Peter Makovicky, and Mark Norell reported the presence of quill knobs on the ulna of a Velociraptor specimen from Mongolia. [133][134][135][136] When they were found at a Dockum Formation quarry in the Texas panhandle in 1984, in a sedimentary strata of a Triassic river delta, the fossils were a jumbled cache of disarticulated bones that may reflect an incident of mass mortality following a flash flood. Troodontids are important to research on the origin of birds because they share many anatomical characters with early birds. Modern computed tomography (CT) scans of a dinosaur chest cavity conducted in 2000 found the apparent remnants of complex four-chambered hearts, much like those found in today's mammals and birds. [166] It had been proposed by Chinese scientists that the animal glided and probably lived in trees, pointing to the fact that wings anchored to the feet of Microraptor would have hindered their ability to run on the ground, and suggest that all primitive dromaeosaurids may have been arboreal.[7]. Functional basis for wing power stroke present in arms and pectoral girdle (during motion, the arms were swung down and forward, then up and backwards, describing a "figure-eight" when viewed laterally). If both feathered hands are rotated upwards and inwards at the same time, the remiges from one hand would collide with those of the other. Bronze cast of the wishbone of "Sue", Field Museum. [191] Additionally, a number of oviraptorid specimens have famously been discovered in a nesting position similar to that of modern birds. in 2003, show not only pennaceous feathers but also true asymmetrical flight feathers, present on the fore and hind limbs and tail. [182] A cladistic analysis indicated that Anchiornis is part of the avian lineage, but outside of the clade that includes Archaeopteryx and modern birds, strongly suggesting that Anchiornis was a basal member of the Avialae and the sister taxon of Aves. Skeletal similarities include the neck, the pubis, the wrists (semi-lunate carpal), the 'arms' and pectoral girdle, the shoulder blade, the clavicle and the breast bone. [42] The Dromaeosauridae family, in particular, seems to have been heavily feathered and at least one dromaeosaurid, Cryptovolans, may have been capable of flight. [156] The bottom portion of the "Archaeoraptor" composite came from a legitimate feathered dromaeosaurid now known as Microraptor,[157] and the upper portion from a previously-known primitive bird called Yanornis.[158]. [168] The holotype also preserved a pygostyle-like structure. These protofeathers suggest that the tyrannosauroids may have been feathered. This life history has resulted in most of the parasite species being … Even if powered flight was not possible, this motion could have aided maneuverability in leaping from branch to branch. They dubbed it Caihong juji—a name that means “rainbow with the big crest” in Mandarin—and think the dino used its flashy neck feathers and a bony crest on its snout to attract mates. Dilong, one of the earliest and most primitive known tyrannosauroids, had a covering of simple feathers or protofeathers, and scales. [173][174] While it is possible that protofeathers existed on parts of the body which have not been preserved, a lack of insulatory body covering is consistent with modern multi-ton mammals such as elephants, hippopotamuses, and most species of rhinoceros. At the time, however, Ornithosuchus seemed to be a likely ancestor of more birdlike creatures. [190] Secondly, at least one oviraptorosaur (Nomingia) was preserved with a tail ending in something like a pygostyle, a bony structure at the end of the tail that, in modern birds, is used to support a fan of feathers. "Velociraptor Had Feathers. A feathered dinosaur is a dinosaur with feathers.It is now thought that all coelurosaurs, and perhaps all theropods, had feathers.. [198] However, a series of what appear to be hollow, tubular bristles, approximately 16 centimeters (6.4 in) long, were also preserved, arranged in a row down the dorsal (upper) surface of the tail. However, feathering would have interfered with the ability of the hands to bring a grasped object up toward the mouth given that extension of the maniraptoran wrist would have caused the hand to rotate slightly upwards on its palmar side. (1996): The questionable validity of. Faint, carbonized feather impressions were preserved in patches in the type specimen. The filaments are preserved with a gap between the bones, which several authors have noted corresponds closely to the expected amount of skin and muscle tissue that would have been present in life. This view remained fairly popular until the 1920s when Gerhard Heilmann's book The Origin of Birds was published in English. Feduccia et al. Since the discovery of such theropods as Microraptor and Epidendrosaurus, paleontologists and scientists in general now have small forms exhibiting some features suggestive of a tree-climbing (or scansorial) way of life. Feathers … "An oviraptorid skeleton from the Late Cretaceous of Ukhaa Tolgod, Mongolia, preserved in an avianlike brooding position over an oviraptorid nest. [185] Scales were also preserved near the base of the tail. Anchiornis also had a more avian wrist than other non-avian theropods. Pp. [165] Using this biplane model, Chatterjee was able to calculate possible methods of gliding, and determined that Microraptor most likely employed a phugoid style of gliding—launching itself from a perch, the animal would have swooped downward in a deep 'U' shaped curve and then lifted again to land on another tree. One of the best examples of soft tissue impressions in a fossil dinosaur was discovered in Petraroia, Italy. [92], Nearly all paleontologists regard birds as coelurosaurian theropod dinosaurs. Comparison of the Psittacosaurus "quills" (top), Sinosauropteryx protofeathers (left) and Tianyulong "filaments" (right). The fossil preserves clear traces of soft tissues. [117] Other researchers not normally involved in the debate over bird origins, such as Zhou, acknowledged that the true affinities of Caudipteryx were debatable. [116][117] The hands of Caudipteryx supported symmetrical, pennaceous feathers that had vanes and barbs, and that measured between 15–20 centimeters long (6–8 inches). [33] A skeleton of Dilong was described in the scientific journal Nature in 2004 that included the first example of "protofeathers" in a tyrannosauroid from the Yixian Formation of China. It is not a member of Aves, despite the efforts of some workers to make it into one. Thus it appears as if some form of feathers or down-like integument would have been present in all maniraptorans, at least when they were young.[169]. Peteinosaurus Facts – Stunning Winged Lizard with extra-long fingers. [98], Though it has been suggested at times that vaned feathers simply must have evolved for flight, the phylogenetic distribution of these structures currently indicates that they first evolved in flightless maniraptorans and were only later exapted by long-armed maniraptorans for use in locomotion. [210] Alvarezsaurids, known from Asia and the Americas, have been variously classified as basal maniraptorans,[209][169][211][212] paravians,[167] the sister taxon of ornithomimosaurs,[213] as well as specialized early birds. It is possible that Anchiornis was able to fly or glide, and may have had a functional airfoil. The innards of Sinosauropteryx and Scipionyx also supposedly falsify avian-like air-sac systems in non-avian coelurosaurs and demonstrate a crocodilian-like hepatic piston diaphragm,[146][147] even though personal interpretation is required to accept that this claim might be correct. Taken from austhrutime.com, here are complete list of Feathered Dinosaurs and when they lived on the Earth. Dyke and Norell (2005) criticized this result for flaws in their mathematical methods, and produced results of their own which supported the opposite conclusion. Elongated arms and forelimbs and clawed manus (hands). [34][77] Another finding pointing to this is the discovery in Nomingia of a pygostyle, a bone that results from the fusion of the last tail vertebrae and is responsible in birds to hold a fan of feathers in the tail. [32], Overall, the filaments most closely resemble the "plumules" or down-like feathers of some modern birds, with a very short quill and long, thin barbs. The holotype of Tianyulong (Zheng et al. The idea that feathers started out as hollow quills also supports Alan Brush's idea that feathers are evolutionary novelties, and not derived from scales. [181] Pedopenna hind wings were smaller and more rounded in shape. The structures might have been simple and unbranched, but Currie & Chen (2001) thought that the structures on Sinosauropteryx might be branched and rather like the feathers of birds that have short quills but long barbs. The ability to fly or glide has been suggested for at least two dromaeosaurid species. The area had repeatedly been smothered in volcanic ash produced by eruptions in Inner Mongolia 124 million years ago, during the Early Cretaceous Period. [61], Large meat-eating dinosaurs had a complex system of air sacs similar to those found in modern birds, according to an investigation which was led by Patrick O'Connor of Ohio University. Tail base hyperflexible, especially dorsally. Part of the jumbled holotype specimen of Beipiaosaurus on the right. Fossil of a juvenile individual of Scipionyx samniticus. During the 1970s, Peter Galton was able to show that all of the claims made about the forelimb and hindlimb anatomy of Hypsilophodon supposedly favoring a scansorial lifestyle were erroneous, and that this animal was in fact well suited for an entirely terrestrial, cursorial lifestyle. Finding quill knobs on Velociraptor, though, means that it definitely had feathers. With the 'arms' spread along the periphery of the nest, a majority of eggs would not be covered by the animal's body unless an extensive coat of feathers was present.[45]. [199] The similarity of these structures with those found on some derived theropods suggests their homology with feathers and raises the possibility that the earliest dinosaurs and their ancestors were covered with analogous dermal filamentous structures that can be considered as primitive feathers (proto-feathers).[199][200]. Sankar Chatterjee determined in 2005 that, in order for the creature to glide or fly, the wings must have been on different levels (as on a biplane) and not overlaid (as on a dragonfly), and that the latter posture would have been anatomically impossible. [25][26] Gatesy and others suggested that anatomical changes to the vertebral column and hindlimbs occured before birds first evolved,[27][28] and Xu Xing and colleagues proved that true functional wings and flight feathers evolved in some maniraptorans,[29][7] all strongly suggesting that these anatomical features were already well-developed before the first birds evolved.[30]. [182] Anchiornis can therefore be considered to be a non-avian avialian. Discovered just two years after Darwin's seminal Origin of Species, its discovery spurred the nascent debate between proponents of evolutionary biology and creationism. Several even show evidence of a second pair of wings on the hind legs, including Microraptor and Cryptovolans. Subsequent dinosaurs found with pennaceous feathers include Pedopenna and Jinfengopteryx. The presence of endosteally derived bone tissues lining the interior marrow cavities of portions of the Tyrannosaurus rex specimen's hind limb suggested that T. rex used similar reproductive strategies, and revealed the specimen to be female. This apparent absence was considered an overwhelming argument to refute the dinosaur ancestry of birds by Danish artist and naturalist Gerhard Heilmann's monumentally influential The Origin of Birds in 1926. [142] In a 2009 article in the journal Acta Palaeontologica Polonica, six velociraptorine dromaeosaurid teeth were described as being recovered from a bone bed in Langenberg Quarry of Oker (Goslar, Germany). [2] In 1868 he published On the Animals which are most nearly intermediate between Birds and Reptiles, making the case. Strongly flexed and subvertical coracoids relative to the scapula. Remiges are the large feathers of the forelimbs (singular remex). in 2009, based on a specimen consisting of the torso, head and neck. [199], Some scientists have argued that other dinosaur proto-feathers are actually fibers of collagen that have come loose from the animals' skins.
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