Therefore, the resultant force R acting on the wing is given by. Analysis of feather distribution on the limbs and tail strongly suggests that pennaceous feathers the type we are familiar with on birds today evolved for reasons other than flight, perhaps for display. & Russell, A. P. Primitive wing feather arrangement in Archaeopteryx lithographica and Anchiornis huxleyi. Communications Biology Physiol. He, T., Wang, X. L. & Zhou, Z. H. A new genus and species of caudipterid dinosaur from the Lower Cretaceous Jiufotang Formation of western Liaoning, China. Re is the Reynolds number for the wing of Caudipteryx, representing the dimensionless ratio of inertial to viscous forces acting on the wing. Exceptional dinosaur fossils show ontogenetic development of early feathers. The mediolateral length and the area of the reconstructed wing are respectively 0.24m and 0.01797m2, the aspect ratio of the fully unfolded wing is 0.32, and the average chord (i.e. Provided by the Springer Nature SharedIt content-sharing initiative. This original function was presumably one for which pennaceous feathers were better suited than the plesiomorphic filamentous feathers, or else the transition in feather morphology would not have occurred. Progress in Aerospace Science 46, 284327 (2010). Yet human visual capability strongly differs from that of birds, and biologically relevant optical cues are not restricted to the plumage that attracts our eye ().Furthermore, the first known non-avian dinosaurs with Wing aspect ratio would have had little effect on metabolic power expenditure. Article J. Exp. The pennaceous feather also has a rachis (or shaft) from which Int. oversaw the project and designed the experiment in principle; C.S., J.K.OC. Lift results when pressure on the lower surface of the wing exceeds pressure on the upper surface. This file contains Supplementary Text 1-6, Supplementary Tables 1-2, a list of Characters 1-356 and additional References. ISSN 0028-0836 (print). Nevertheless, the experiments and theoretical analyses broadly agree in indicating that the wings of a running Caudipteryx would not have been capable of generating substantial lift and drag. You are using a browser version with limited support for CSS. Pennaceous feather section length was not affected by habitat, perhaps reflecting the importance of the distal part of body feathers in the formation of the outer, Z. The wing outline reconstructed in our study is shown in the inset to Fig. 3c,d. Syst. WebPennaceous feathers. PubMed Historical Biology 16, 8592 (2004). Science 346, 1253293 (2014). Pennaceous feathers undoubtedly provided some degree of insulation in oviraptorosaurs, but it is unlikely that they were more useful in this capacity than their filamentous counterparts, so selection pressure for improved insulation probably was not responsible for the feather transition. & OConnor, J. K. Complexities and novelties in the early evolution of avian flight, as seen in the Mesozoic Yanliao and Jehol Biotas of northeast China. Furthermore, the wing plumage demonstrates that several recent interpretations8,9 are problematic. Proc. Sengupta, T. K. Theoretical and Computational Aerodynamics. Fig. & Kambic, R. E. The predatory ecology of Deinonychus and the origin of flapping in birds. Vertebrata PalAsiatica 38, 241254 (2000). the air velocity becomes zero near the upper surface of the wing) at angles greater than about 45. Rx decreases with airflow angle for all speeds considered, whereas Ry is unaffected by airflow angle (being nearly constant at around 0.2N) at v=2m/s but decreases very slightly with airflow angle at higher speeds. Because it is unlikely that Caudipteryx had a range of shoulder joint motion approaching that of modern birds, we considered only six modest flapping angles (=10, 5, 0, 5, 10 and 20, with negative values corresponding to elevation and positive ones to depression) in this part of our analysis. Oliver W. M. Rauhut. Thus the structure of the vane is more open than generally realized. Poore, S. O., Sanchezhaiman, A. We initially considered the wing of Caudipteryx to be a thin rectangular plate, which could be held extended laterally from the shoulder at varying angles of attack. 6a,b); aerodynamic pressure over the top and bottom surfaces of the wing (Fig. We used mathematical analyses, computer simulations and experiments on a robot Caudipteryx with realistic wing proportions to test whether the wings of Caudipteryx could have generated aerodynamic forces useful in rapid terrestrial locomotion. Barb ridges of juvenile feathers merge with the rachidial ridge so that pennaceous feathers are formed. Displacement of (d) and stress (Von Mises) within (e) the substance of the wing. S2). 22, 16 (2012), Xu, X. Aerodynamic analysis of the wing of Caudipteryx as a rectangular plate extending laterally from the body during running at an arbitrary angle of inclination in moving air. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Among paravians, by contrast, pennaceous feathers formed the basis of a sophisticated aerodynamic apparatus permitting aerial locomotion in birds, the dromaeosaurid Microraptor16, and perhaps basal paravians in general17. University of Chicago Press 16, 283301 (2015). Science 328, 887889 (2010), Longrich, N. R., Vinther, J., Meng, Q., Li, Q. Hind wings in basal birds and the evolution of leg feathers. While the gross organization (i.e., a short distal vane and a long, naked rhachis) of these feathers 5). Biol. Determining a realistic value for CD is more complicated. Displacement is concentrated near the leading edge of the wing, and bending and torsional stresses are concentrated on the shoulder joint and in the forelimb skeleton. Furthermore, our analysis suggests that the wings of Caudipteryx would have had negligible effects on its terrestrial locomotion even when they were held fully extended from the body in a symmetrical manner. Nature 455, 11051108 (2008). (PDF 1909 kb), Foth, C., Tischlinger, H. & Rauhut, O. The amplitude of the relative velocity v can be calculated based on the cosine law of triangles: where vx and vy represent the horizontal and vertical components of the absolute speed of the Caudipteryx wing (i.e. Pennaceous feathers have a rachis with vanes or vaxillum spreading to either side. Extended Data Figure 7 Phylogenetic hypothesis used for tracing plumage characters. Bull. In many cases aspect ratio was used as a proxy for the amount of wing unfolding, with larger aspect ratios corresponding to larger wing areas (because the wing was assumed to be more fully deployed). Webthe evolution of pennaceous feathers is generally decoupled from the origin of flight and might be related to other biological roles. & Brush, A. H. The evolutionary origin and diversification of feathers. Correspondence to 93, 961975 (2015). Zhou, Z. H., Wang, X. L., Zhang, F. C. & Xu, X. Nature 511, 7982 (2014). In dramatic contrast to pennaceous et al. This is appropriate because the gaps between the ends of the individual remiges on the forelimb of Caudipteryx would act aerodynamically as slots. WebStudy with Quizlet and memorize flashcards containing terms like What are pennaceous feathers?, what do contour feathers do for the birds?, what are wing feathers used for and called?? Nature 498, 359362 (2013), Prum, R. O. This pressure imposed by the airflow causes variable amounts of stress and deflection across the wing surface. This part of analysis is thus physically unrealistic in that, during running with the wing held fixed at a particular angle rather than actively moving up and down, no force would be available to produce the wing twisting that is being assumed to occur. Researchers have figured out how desert sandgrouse use their feathers to sustain thirsty chicks. See Supplementary Information for details. 77, 261295 (2002), Article At the lowest speeds considered (2m/s and 4m/s), Rx and Ry are both low, being respectively less than 0.1N and less than 0.5N. Rx tends to decrease slightly with aspect ratio, and Ry to increase slightly, whereas both Rx and Ry increase considerably at higher running speeds. If pennaceous feathers were not being used for volant behaviours in oviraptorosaurs, what function did they serve? The origin and early evolution of feathers: insights from recent paleontological and neontological data. At the lower wind speed of 3.5m/s, the two wings produced a total of 0.32N of lift and 0.15N of drag, whereas at the higher wind speed of 6.0m/s they produced 0.55N of lift and 0.29N of drag (Table1). In this situation the relative velocity of the airflow with respect to the wing, v, is the resultant of v1 and v2: v2 = v2v1 (Fig. This analysis indicates that lift and drag would both have been considerably greater at higher running speeds, while higher aspect ratios (i.e. The constant term in this equation represents the total strength possessed by the air making up a particular streamline (i.e. The Mesozoic radiation of birds. A pennaceous feather has a stalk or quill. Feathers were coated in platinum then viewed under a field emission scanning electron microscope (FESEM; Hitachi S-400; Hitachi, Tokyo, Japan) at magnifications between 40 and 4000. In the next stage of our theoretical analysis, we modelled the interaction between the wing of Caudipteryx and the surrounding air in more concrete and physically explicit terms. 1) is the best known; several specimens of the two species C. dongi and C. zoui having been described from the Lower Cretaceous Yixian Formation of northeast China10,11,12. [1] ADS However, the aerodynamic forces on each wing would have been small, not exceeding 0.05N in magnitude. and JavaScript. ISSN 1476-4687 (online) Scale bar, 5cm. Nature 475, 465470 (2011), Article Der Urvogel von Solnhofen (Dr Friedrich Pfeil, 2008), Ji, Q., Currie, P. J., Norell, M. A. Radar measurements of speeds. Because the outline of the wing of Caudipteryx approximates an ellipse, we assign k a value of equal to /4, appropriate for an elliptical wing. Google Scholar. Zhang, F. C., Zhou, Z. H., Xu, X., Wang, X. L. & Sullivan, C. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers. Total metabolic power would have increased sharply with velocity, but would have been no higher than about 6J/s even at the maximum estimated running speed of 8m/s. We used the software package ABAQUS to estimate the aerodynamic forces associated with holding the wing fixed in each downstroke position. Feathers are one of the most characteristic evolutionary novelties of birds, and until recently a broad consensus existed that typical carried out the experiments and completed the 3D reconstruction and video of the Caudipteryx robot; J.-S.Z. If material is not included in the articles Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. Nature The wing-like forelimb feathers are proportionately shorter than in potentially volant animals, but their sheet-like arrangement suggests the potential to produce small aerodynamic forces. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. CAS 198, 10291033 (1995). The authors declare no competing interests. PLoS ONE 11(4), e0153446, https://doi.org/10.1371/journal.pone.0153446 (2016). Figure4b,c shows curves representing total Rx and Ry for the two wings as functions of aspect ratio, for a variety of running speeds but with an airstream moving at v2=0.5m/s and at an angle of =15 above the horizontal. Structural attributes contributing to locomotor performance in the ostrich. Cambridge University Press, (2015). Introduction to the Aerodynamics of Flight. b, Reduced consensus tree of the pruned data matrix after the exclusion of Shenzhousaurus, Segnosaurus, Erliansaurus, Albinykus, Saurornitholestes, Harygryphus, Tianyuraptor, Hesperonychus, Pyroraptor, Lithornis, Liaoningornis and Limneavis. Alerstam, T. et al. Hubel, T. Y. In this situation the aspect ratio of the wing, which would effectively vary with the degree of wing folding, would have an effect on the horizontal and vertical components of the resultant force (Rx and Ry), which approximately correspond to drag and lift for small values of . Discoveries of bird-like theropod dinosaurs and basal avialans in recent decades have helped to put the iconic Urvogel Archaeopteryx1 into context2,3,4,5,6 and have yielded important new data on the origin and early evolution of feathers7. This raises the question of why oviraptorosaurs possessed pennaceous feathers on their forelimbs. RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH. produced the cladogram showing the phylogenetic position of Caudipteryx, established the parameters for reconstructing Caudipteryx based on fossil evidence, and provided major suggestions in revision; all authors discussed the results, commented on the manuscript, and contributed ideas to manuscript development and data analysis. Sci Rep 8, 17854 (2018). A realistic 3D wing geometry was assumed in this part of the analysis, and Caudipteryx was considered to be running horizontally in still air at a speed of 8m/s. ( A) Beipiaosaurus sp. https://doi.org/10.1007/s00114-008-0488-3 (2008). WebObservations with a scanning electron microscope demonstrate that basic to the structure of pennaceous feathers is the lamelliform structure of barbules, the planes of which are oriented at right angles to the plane of the feather vane. To obtain 86, 91102 (2012), Xu, X., Zheng, X. the shoulder joint) and the forelimb skeleton experience considerable bending and torsional stresses (Fig. Google Scholar. Although pennaceous feathers have the obvious functional advantage over the filamentous feathers of non-pennaraptoran theropods of being capable of forming aerodynamic surfaces with potential utility in volant behaviours (flapping flight and/or gliding), it is clear that pennaceous feathers evolved first for some other function and were later exapted for flight. This study was supported by the Volkswagen Foundation under grant I/84 640 (to O.W.M.R.). Furthermore, we did not explicitly model flapping behaviour in our study. The Journal of Experimental Biology 210, 31353146 (2007).