Skip to main content

The dorsal appendages of the Triassic reptile Longisquama insignis: reconsideration of a controversial integument type

Abstract

Elongated skin projections of the reptile Longisquama insignis from the Triassic of Kyrgyzstan are preserved as imprints on the only skeletal specimen and on seven additional pairs of fossil slabs and counter-slabs from the same locality and horizon. The integumentary structures became a matter of debate when they were assessed as “non-avian feathers” homologous to avian feathers. Conflicting interpretations of their morphology and relationship to other appendage types arose from the ambiguity of the fossil skin impressions. On the basis of comparative description of the individual morphology of all yet known Longisquama specimens we address aspects of taphonomy, development, and function and define to what extent Longisquama’s appendages share characteristics of avian vaned feathers. We explain the existing feather similarity by their development from a filamentous primordium and a complex sequence of individual processes, some of which are reminiscent of processes observed in feather development. Such an interpretation is in agreement with a set of homologous mechanisms of appendage morphogenesis in an archosauromorph clade including Longisquama and feather-bearing archosaurs but does not necessarily require that the appendages of Longisquama themselves are feathers or high-level feather homologues.

Kurzfassung

Längliche Hautvorsprünge des Reptils Longisquama insignis aus der Trias Kirgisistans sind in Zusammenhang mit dem einzigen Fossilskelett sowie isoliert auf der Platte und Gegenplatte von sieben weiteren Exemplaren aus demselben Fundhorizont und von derselben Fundstätte erhalten. Die Hautstrukturen wurden Teil der Debatte um den Ursprung der Federn, als manche Bearbeiter sie als Federn eines Nichtvogels, die homolog zu Vogelfedern seien, auffassten. Im Widerspruch zueinander stehende Interpretationen zu ihrer Morphologie und Vergleichbarkeit mit anderen Typen von Hautanhängen waren besonders auch der Mehrdeutigkeit der fossilen Hauteindrücke geschuldet. Auf der Grundlage eines Vergleichs der Morphologien aller bekannten Longisquama-Anhänge nehmen wir zu Fragen der Taphonomie, Entwicklung und Funktion der Anhänge Stellung, ebenso zu der Frage, inwieweit sie den Vogelfedern mit Federfahne glichen. Wir erklären die bestehende Federähnlichkeit der Longisquama-Anhänge mit der Entwicklung aus einer filamentartigen Anlage und einer komplexen Abfolge von Einzelvorgängen, von denen manche Entwicklungprozessen heutiger Federn geglichen haben könnten. Solch eine Interpretation ist mit der Hypothese in Einklang, dass Mitglieder einer Archosauromorpha-Klade, die Longisquama und federtragende Archosaurier einschließt, eine Reihe homologer Enwicklungsmechanismen für Hautanhänge besitzen, erfordert jedoch nicht, dass die Longisquama-Anhänge selbst Federn oder auf einem hohen Level homolog mit Federn sind.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

References

  • Alibardi, L. 2007. Keratinization of sheath and calamus cells developing and regenerating feathers. Annals of Anatomy 189: 583–595.

    Article  Google Scholar 

  • Alibardi, L., L.W. Knapp, and R.H. Sawyer. 2006. Beta-keratin localization in developing alligator scale and feathers in relation to the development and evolution of feathers. Journal of Submicroscopic Cytology and Pathology 38: 175–192.

    Google Scholar 

  • Alibardi, L., and M. Toni. 2008. Cytochemical and molecular characteristics of the process of cornification during feather morphogenesis. Progress in Histochemistry and Cytochemistry 43: 1–69.

    Article  Google Scholar 

  • Bakhurina, N.N., and D.M. Unwin. 1995. A preliminary report on the evidence of “hair” in Sordes pilosus, an Upper Jurassic pterosaur from Middle Asia. In Sixth symposium on mesozoic terrestrial ecosystems and biota, short papers, ed. A. Sun, and Y. Wang, 79–82. Beijing: China Ocean Press.

    Google Scholar 

  • Bonde, N., and P. Christiansen. 2003. The detailed anatomy of Rhamphorhynchus: axial pneumaticity and its implications. In Evolution and paleobiology of pterosaurs, ed. E. Buffetaut, and J.-M. Mazin. London: The Geological Society. (Special Publications 217: 217–232).

    Google Scholar 

  • Briggs, D.E.G. 2003. The role of decay and mineralization in the preservation of soft-bodied fossils. Annual Review of Earth and Planetary Sciences 31: 275–301.

    Article  Google Scholar 

  • Buchwitz, M., and S. Voigt. 2010. Peculiar carapace structure of a Triassic chroniosuchian implies evolutionary shift in trunk flexibility. Journal of Vertebrate Paleontology 30: 1697–1708.

    Article  Google Scholar 

  • Chang, C., P. Wu, R.E. Baker, P.K. Maini, L. Alibardi, and C.-M. Chuong. 2009. Reptile scale paradigm: Evo-devo, pattern formation and regeneration. International Journal of Developmental Biology 53: 813–826.

    Article  Google Scholar 

  • Chen, P., Z. Dong, and S. Zhen. 1998. An exceptionally well-preserved theropod dinosaur from the Yixian Formation of China. Nature 391: 147–152.

    Article  Google Scholar 

  • Cowen, R. 1981. Homonyms of Podopteryx. Journal of Paleontology 55: 483.

    Google Scholar 

  • Chuong, C.-M., R. Chodankar, R.B. Widelitz, and T.-X. Jiang. 2000. Evo-devo of feathers and scales: Building complex epithelial appendages. Current Opinion in Genetics and Development 10: 449–456.

    Article  Google Scholar 

  • Currie, P.J., and P.-J. Chen. 2001. Anatomy of Sinosauropteryx prima from Liaoning, northeastern China. Canadian Journal of Earth Sciences 38: 1705–1727.

    Article  Google Scholar 

  • Dalla Valle, L., A. Nardi, C. Gelmi, M. Toni, D. Emera, and L. Alibardi. 2009. β-Keratins of the crocodilian epidermis: Composition, structure, and phylogenetic relationships. Journal of Experimental Zoology 312B: 42–57.

    Article  Google Scholar 

  • Davis, P.G., and D.E.G. Briggs. 1995. Fossilization of feathers. Geology 23: 783–786.

    Article  Google Scholar 

  • Dhouailly, D. 2009. A new scenario for the evolutionary origin of hair, feather, and avian scales. Journal of Anatomy 214: 587–606.

    Article  Google Scholar 

  • Dobruskina, I.A. 1994. Triassic floras of Eurasia. Österreichische Akademie der Wissenschaften. Schriftenreihe der Erdwissenschaftlichen Kommissionen 10: 1–422.

    Google Scholar 

  • Dobruskina, I.A. 1995. Keuper (Triassic) flora from Middle Asia (Madygen, Southern Fergana). New Mexico Museum of Natural History and Science Bulletin 5: 1–49.

    Google Scholar 

  • Dyke, G.J., R.L. Nudds, and J.M.V. Rayner. 2006. Flight of Sharovipteryx mirabilis: the world’s first delta-winged glider. Journal of Evolutionary Biology 19: 1040–1043.

    Article  Google Scholar 

  • Evans, S.E. 1988. The early history and relationships of Diapsida. In The phylogeny and classification of tetrapods, volume 1: Amphibians, reptiles, birds, ed. M.J. Benton, 221–260. Oxford: Clarendon Press.

    Google Scholar 

  • Fastovsky, D.E., and D.B. Weishampel. 2004. The evolution and extinction of the dinosaurs, 485. Cambridge: Cambridge University Press.

    Google Scholar 

  • Fischer, J., S. Voigt, J.W. Schneider, M. Buchwitz, and S. Voigt. 2011. A selachian freshwater fauna from the Triassic of Kyrgyzstan and its implications for Mesozoic shark nurseries. Journal of Vertebrate Paleontology 31: 937–953.

    Article  Google Scholar 

  • Frances, J.F., and J. A. Pourtless IV. 2009. Cladistics and the origin of birds: A review and two new analyses. Ornithological Monographs 66: 1–78.

    Article  Google Scholar 

  • Fraser, N.C. 2006. Dawn of the Dinosaurs: Life in the triassic, 328. Bloomington and Indianapolis: Indiana University Press.

    Google Scholar 

  • Frey, E., and D.M. Martill. 1999. Soft tissue preservation in a specimen of Pterodactylus kochi from the Upper Jurassic of Germany. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 210: 421–441.

    Google Scholar 

  • Gans, C., I. Darevskii, and L.P. Tatarinov. 1987. Sharovipteryx, a reptilian glider? Paleobiology 13: 415–426.

    Google Scholar 

  • Greenwold, M.J., and R.H. Sawyer. 2011. Linking the molecular evolution of avian beta (β) keratins to the evolution of feathers. Journal of Experimental Zoology 316B: 609–616.

    Article  Google Scholar 

  • Harris, M.P., S. Williamson, J.F. Fallon, H. Meinhardt, and R.O. Prum. 2005. Molecular evidence for an activator-inhibitor mechanism in development of embryonic feather branching. Proceedings of the National Academy of Sciences 102: 11734–11739.

    Article  Google Scholar 

  • Haubold, H., and E. Buffetaut. 1987. A new interpretation of Longisquama insignis, an enigmatic reptile from the Upper Triassic of Central Asia. Comptes Rendus de l’Académie des Sciences Série 2(305): 65–70.

    Google Scholar 

  • Hill, R.V. 2006. Comparative anatomy and histology of xenarthran osteoderms. Journal of Morphology 267: 1441–1460.

    Article  Google Scholar 

  • Hone, D.W.E., and M.J. Benton. 2007. An evaluation of the phylogenetic relationships of the pterosaurs among archosauromorph reptiles. Journal of Systematic Palaeontology 5: 465–469.

    Article  Google Scholar 

  • Ivakhnenko, M.F. 1978. Urodelans from the Triassic and Jurassic of Soviet Central Asia. Paleontological Journal 1978: 362–368. (In Russian).

    Google Scholar 

  • Ji, Q., and C. Yuan. 2002. Discovery of two kinds of protofeathered pterosaurs in the Mesozoic Daohugou Biota in the Ningcheng Region and its stratigraphic and biologic significances. Geological Review 48: 221–224.

    Google Scholar 

  • Ji, Q., P.J. Currie, M.A. Norell, and S. Ji. 1998. Two feathered dinosaurs from northeastern China. Nature 393: 753–761

    Article  Google Scholar 

  • Jones, T.D., J.A. Ruben, L.D. Martin, E.N. Kurochkin, A. Feduccia, P.F.A. Maderson, W.J. Hillenius, N.R. Geist, and V. Alifanov. 2000. Nonavian feathers in a Late Triassic Archosaur. Science 288: 2202–2205.

    Article  Google Scholar 

  • Jones, T.D., J.A. Ruben, P.F.A. Maderson, and L.D. Martin. 2001. Longisquama fossil and feather morphology. Science 291: 1901–1902.

    Google Scholar 

  • Kellner, A.W.A., X. Wang, H. Tischlinger, D.A. Campos, D.W.E. Hone, and X. Meng. 2010. The soft tissue of Jeholopterus (Pterosauria, Anurognathidae, Batrachognathinae) and the structure of the pterosaur wing membrane. Proceedings of the Royal Society B 277: 321–329.

    Article  Google Scholar 

  • Kogan, I., K. Schöneberger, J. Fischer, and S. Voigt. 2009. A nearly complete skeleton of Saurichthys orientalis (Pisces, Actinopterygii) from the Madygen Formation (Middle to Late Triassic, Kyrgyzstan, Central Asia) - preliminary results. Freiberger Forschungshefte C 532: 139–152.

    Google Scholar 

  • Lloyd, G.T., K.E. Davis, D. Pisani, J.E. Tarver, M. Ruta, M. Sakamoto, D.W.E. Hone, R. Jennings, and M.J. Benton. 2008. Dinosaurs and the cretaceous terrestrial revolution. Proceedings of the Royal Society B 275: 2483–2490.

    Article  Google Scholar 

  • Lucas, A.M., and P.R. Stettenheim. 1972. Avian anatomy: Integument. Washington, DC: US Department of Agriculture.

    Google Scholar 

  • Main, R.P., A. de Ricqlès, J.R. Horner, and K. Padian. 2005. The evolution and function of thyreophoran dinosaur scutes: Implications for plate function in stegosaurs. Paleobiology 31: 291–314.

    Article  Google Scholar 

  • Martin, L.D. 2004. A basal archosaurian origin of birds. Acta Zoologica Sinica 50: 978–990.

    Google Scholar 

  • Mayr, G., S.D. Peters, G. Plodowski, and O. Vogel. 2002. Bristle-like integumentary structures at the tail of the horned dinosaur Psittacosaurus. Naturwissenschaften 89: 361–365.

    Article  Google Scholar 

  • Norell, M., Q. Ji, K. Gao, C. Yuan, Y. Zhao, and L. Wang. 2002. ‘Modern’ feathers on a non-avian dinosaur. Nature 416: 36.

    Article  Google Scholar 

  • Norell, M., and X. Xu. 2005. Feathered dinosaurs. Annual Review of Earth and Planetary Sciences 33: 277–299.

    Article  Google Scholar 

  • Ord, T.J., D.T. Blumstein, and C.S. Evans. 2002. Ecology and signal evolution in lizards. Biological Journal of the Linnean Society 77: 127–148.

    Article  Google Scholar 

  • Paul, G.S. 2001. Dinosaurs of the air: the evolution and loss of flight in dinosaurs and birds. Baltimore and London: John Hopkins University Press.

    Google Scholar 

  • Peters, D. 2000. A re-examination of four prolacertiforms with implications for pterosaur phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106: 293–336.

    Google Scholar 

  • Prum, R.O. 1999. Development and evolutionary origin of feathers. Journal of Experimental Zoology 285B: 291–306.

    Article  Google Scholar 

  • Prum, R.O. 2001. Longisquama fossil and feather morphology. Science 291: 1899–1900.

    Article  Google Scholar 

  • Prum, R.O., and A.H. Brush. 2002. The evolutionary origin and diversification of feathers. Quarterly Review of Biology 77: 261–295.

    Google Scholar 

  • Reisz, R.R., and H.-D. Sues. 2000. Palaeontology: The ‘feathers’ of Longisquama. Nature 408: 428.

    Google Scholar 

  • Renesto, S., and G. Binelli. 2006. Vallesaurus cenensis Wild 1991, a drepanosaurid (Reptilia, Diapsida) from the Late Triassic of northern Italy. Rivista Italiana di Paleontologia e Stratigrafia 112: 77–94.

    Google Scholar 

  • Renesto, S., J.A. Spielmann, S.G. Lucas, and G.T. Spagnoli. 2010. The taxonomy and paleobiology of the Late Triassic (Carnian-Norian: Adamanian-Apachean) drepanosaurs (Diapsida: Archosauromorpha: Drepanosauromorpha). New Mexico Museum of Natural History and Science Bulletin 46: 1–81.

    Google Scholar 

  • Rietschel, S. 1985. Feathers and wings of Archaeopteryx, and the question of her flight ability. In The beginnings of birds, ed. M.K. Hecht, J.H. Ostrom, G. Viohl, and P. Wellnhofer, 251–260. Eichstätt: Freunde des Jura-Museums.

    Google Scholar 

  • Sawyer, R.H., and L.W. Knapp. 2003. Avian skin development and the evolutionary origin of feathers. Journal of Experimental Zoology 298B: 57–72.

    Article  Google Scholar 

  • Sawyer, R.H., B.A. Salvatore, T.F. Potylicki, J.O. French, T.C. Glenn, and L.W. Knapp. 2003a. Origin of feathers: feather beta keratins are expressed in discrete epidermal cell populations of embryonic scutate scales. Journal of Experimental Zoology 295B: 12–24.

    Article  Google Scholar 

  • Sawyer, R.H., L.D. Washington, B.A. Salvatore, T.C. Glenn, and L.W. Knapp. 2003b. Origin of archosaurian integumentary appendages: The bristles of the wild turkey beard express feather-type beta keratins. Journal of Experimental Zoology 297B: 27–34.

    Article  Google Scholar 

  • Schoch, R.R., S. Voigt, and M. Buchwitz. 2010. A chroniosuchid from the Triassic of Kyrgyzstan and analysis of chroniosuchian relationships. Zoological Journal of the Linnean Society 160: 515–530.

    Article  Google Scholar 

  • Scotland, R.W. 2010. Deep homology: A view from systematics. BioEssays 32: 438–449.

    Article  Google Scholar 

  • Senter, P. 2004. Phylogeny of Drepanosauridae (Reptilia: Diapsida). Journal of Systematic Palaeontology 2: 257–268.

    Article  Google Scholar 

  • Sereno, P. 1991. Basal archosaurs: Phylogenetic relationships and functional implications. Society of Vertebrate Paleontology Memoir 2: 1–53.

    Article  Google Scholar 

  • Sereno, P. 1999. The evolution of dinosaurs. Science 284: 2137–2147.

    Article  Google Scholar 

  • Sharov, A.G. 1966. Unique finds of reptiles from Mesozoic deposits of Central Asia. Bulletin of Moscow Society of Naturalists, Geological Section (Bjulleten’ Moskovskogo Obscestva Ispytatelej Prirody, Otdel geologiceskij) 41(2): 145–146. (in Russian).

    Google Scholar 

  • Sharov, A.G. 1970. An unusual reptile from the Lower Triassic of Fergana. Paleontological Journal 1970: 112–116. (In Russian).

    Google Scholar 

  • Sharov, A.G. 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kyrgyzstan. Transactions of the Palaeontological Institute (Trudy Paleontologicheskogo Instituta Akademiya Nauk SSSR) 130: 104–113. (in Russian).

    Google Scholar 

  • Shcherbakov, D.E. 2002. The 270 million year history of Auchenorrhyncha (Homoptera). Denisia 4: 29–36.

    Google Scholar 

  • Shcherbakov, D.E. 2008a. Madygen, Triassic Lagerstätte number one, before and after Sharov. Alavesia 2: 113–124.

    Google Scholar 

  • Shcherbakov, D.E. 2008b. Insect recovery after the Permian/Triassic crisis. Alavesia 2: 125–131.

    Google Scholar 

  • Shcherbakov, D.E. 2011. New and little-known families of Hemiptera Cicadomorpha from the Triassic of Central Asia—Early analogs of treehoppers and planthoppers. Zootaxa 2836: 1–26.

    Google Scholar 

  • Shubin, N., C. Tabin, and S. Carroll. 1997. Fossils, genes and the evolution of animal limbs. Nature 388: 639–648.

    Article  Google Scholar 

  • Shubin, N., C. Tabin, and S. Carroll. 2009. Deep homology and the origins of evolutionary novelty. Nature 457: 818–823.

    Article  Google Scholar 

  • Sixtel, T.A. 1960. Stratigraphy of the continental deposits of the Upper Permian and Triassic of Central Asia. Transactions of the Tashkent State University V. I. Lenin (Trudy Tashkentskogo Gosudarstvennogo Universiteta Imeni V. I. Lenina) 176: 1–146. (in Russian).

    Google Scholar 

  • Sixtel, T. A. 1962. Flora of the Late Permian and Early Triassic in Southern Fergana. Stratigrafia i paleontologia Uzbekistana i sopredelnych rayonov, kniga 1: 272–414 (Tashkent) (in Russian).

  • Stephan, B. 2003. The verifiable structures of the Archaeopteryx feathers with notes on Longisquama and diverse Proavis models. Mitteilungen des Museums für Naturkunde Berlin, Geowissenschaftliche Reihe 6: 183–193.

    Article  Google Scholar 

  • Sytchevskaya, E.K. 1999. Freshwater fish fauna from the Triassic of Northern Asia. In Mesozoic fishes 2: Systematics and fossil record, ed. G. Arratia, and H.-P. Schultze, 445–468. Munich: Verlag Dr. Friedrich Pfeil.

    Google Scholar 

  • Tatarinov, L.P. 2005. A new cynodont (Reptilia, Theriodontia) from the Madygen formation (Triassic) of Fergana. Kyrgyzstan. Paleontological Journal 39(2): 192–198.

    Google Scholar 

  • Unwin, D.M., V.R. Alifanov, and M.J. Benton. 2000. Enigmatic small reptiles from the Middle-Late Triassic of Kirgizstan. In The age of dinosaurs in Russia and Mongolia, ed. M.J. Benton, M.A. Shishkin, D.M. Unwin, and E.N. Kurochkin, 177–186. Cambridge: Cambridge University Press.

    Google Scholar 

  • Unwin, D.M., and M.J. Benton. 2001. Longisquama fossil and feather morphology. Science 291: 1900–1901.

    Google Scholar 

  • Voigt, S., M. Buchwitz, J. Fischer, D. Krause, and R. Georgi. 2009. Feather-like development of Triassic diapsid skin appendages. Naturwissenschaften 96: 81–86.

    Article  Google Scholar 

  • Voigt, S., H. Haubold, S. Meng, D. Krause, J. Buchantschenko, K. Ruckwied, and A.E. Götz. 2006. The Madygen lagerstätte: A contribution to the geology and palaeontology of the Madygen Formation (Middle to Upper Triassic, SW Kyrgyzstan, Central Asia). Hallesches Jahrbuch für Geowissenschaften B 22: 85–119.

    Google Scholar 

  • Vickaryous, M.K., and B.K. Hall. 2008. Development of the dermal skeleton in Alligator mississippiensis (Archosauria, Crocodylia) with comments on the homology of osteoderms. Journal of Morphology 269: 398–422.

    Article  Google Scholar 

  • Vickaryous, M.K., and J.-Y. Sire. 2009. The integumentary skeleton of tetrapods: Origin, evolution, and development. Journal of Anatomy 214: 441–464.

    Article  Google Scholar 

  • Vorobyeva, E.I. 1967. A Triassic Ceratodus from Southern Fergana and some notes on the systematic and phylogeny of the family Ceratodontidae. Paleontological Journal 1967: 80–87. (in Russian).

    Google Scholar 

  • Wang, X., Z. Zhou, F. Zhang, and X. Xu. 2002. A nearly completely articulated rhamphorhynchoid pterosaur with exceptionally well-preserved wing membranes and “hairs” from Inner Mongolia, northeast China. Chinese Science Bulletin 47: 226–230.

    Article  Google Scholar 

  • Watkins, G.G. 1998. Function of a secondary sexual ornament: The crest in the South American iguanian lizard Microlophus occipitalis (Peters, Tropiduridae). Herpetologica 54: 161–169.

    Google Scholar 

  • Widelitz, R.B., T.X. Jiang, M. Yu, T. Shen, J.-Y. Shen, P. Wu, Z. Yu, and C.-M. Chuong. 2003. Molecular biology of feather morphogenesis: A testable model for Evo-devo research. Journal of Experimental Zoology 298B: 109–122.

    Article  Google Scholar 

  • Wu, P., L. Hou, M. Plikus, M. Hughes, J. Scehnet, S. Suksaweang, R.B. Widelitz, T.-X. Jiang, and C.-M. Chuong. 2004. Evo-devo of amniote integuments and appendages. International Journal of Developmental Biology 48: 249–270.

    Article  Google Scholar 

  • Xu, X. 2004. Feathered dinosaurs from China and the evolution of major avian characters. Integrative Zoology 1: 4–11.

    Article  Google Scholar 

  • Xu, X. 2006. Scales, feathers and dinosaurs. Nature 440: 287–288.

    Article  Google Scholar 

  • Xu, X., and M.A. Norell. 2004. Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids. Nature 431: 680–684.

    Article  Google Scholar 

  • Xu, X., Z.-J. Tang, and X.-J. Wang. 1999a. A therizinosauroid dinosaur with integumentary structures from China. Nature 399: 350–354.

    Article  Google Scholar 

  • Xu, X., X.-L. Wang, and X.-C. Wu. 1999b. A dromaeosaurid dinosaur with a filamentous integument from the Yixian Formation of China. Nature 401: 262–266.

    Article  Google Scholar 

  • Xu, X., X. Zheng, and H. You. 2009. A new feather type in a nonavian theropod and the early evolution of feathers. Proceedings of the National Academy of Sciences 106: 832–834.

    Article  Google Scholar 

  • Xu, X., Z. Zhou, and R.O. Prum. 2001. Branched integumental structures in Sinornithosaurus and the origin of feathers. Nature 410: 200–204.

    Article  Google Scholar 

  • Xu, X., Z.-H. Zhou, X.-L. Wang, X.-W. Kuang, F.-C. Zhang, and X.-G. Du. 2003. Four-winged dinosaurs from China. Nature 421: 335–339.

    Article  Google Scholar 

  • Yu, M., P. Wu, R.B. Widelitz, and C.M. Chuong. 2002. The morphogenesis of feathers. Nature 420: 308–312.

    Article  Google Scholar 

  • Yu, M., Z. Yue, P. Wu, D.-Y. Wu, J.-A. Mayer, M. Medina, R.B. Widelitz, T.-X. Jiang, and C.-M. Chuong. 2004. The developmental biology of feather follicles. International Journal of Developmental Biology 48: 181–191.

    Article  Google Scholar 

  • Yue, Z., T.-X. Jiang, R.B. Widelitz, and C.-M. Chuong. 2006. Wnt3a gradient converts radial to bilateral feather symmetry via topological arrangement of epithelia. Proceedings of the National Academy of Sciences 103: 951–955.

    Article  Google Scholar 

  • Zheng, X., H. You, X. Xu, and Z. Dong. 2009. An early cretaceous heterodontosaurid dinosaur with filamentous integumentary structures. Nature 458: 333–336.

    Article  Google Scholar 

  • Zhou, Z.-H., P.M. Barrett, and J. Hilton. 2003. An exceptionally preserved lower cretaceous ecosystem. Nature 421: 807–814.

    Article  Google Scholar 

Download references

Acknowledgments

This work was supported by the State of Saxony (scholarship to M. B.) and by the German Research Foundation (DFG II—VO 1466/1-1). We are grateful to Evgenii N. Kurochkin and Vladimir R. Alifanov for access to the type material in Moscow in February 2007, to Jan Fischer, Daniel Krause, and Robert Georgi for discussion and for their support during the 2007 field season, to Ilja Kogan for his help with translation of Russian publications and reports, and to Christian Foth, Nicholas Fraser, and Jörg W. Schneider for their comments on earlier versions of the manuscript.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Michael Buchwitz.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Buchwitz, M., Voigt, S. The dorsal appendages of the Triassic reptile Longisquama insignis: reconsideration of a controversial integument type. Paläontol Z 86, 313–331 (2012). https://doi.org/10.1007/s12542-012-0135-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12542-012-0135-3

Keywords

  • Diapsida
  • Fossil skin
  • Feather development
  • Deep homology
  • Display structure
  • Madygen Formation

Schlüsselwörter

  • Diapsida
  • Fossile Haut
  • Federentwicklung
  • Tiefenhomologe
  • Zurschaustellung
  • Madygen-Formation