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The problem of dinosaur origins: integrating three approaches to the rise of Dinosauria

Published online by Cambridge University Press:  25 September 2013

Kevin Padian*
Affiliation:
Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, CA 94720-4780, USA. Email: [email protected]

Abstract

The problem of the origin of dinosaurs has historically had three dimensions. The first is the question of whether Dinosauria is monophyletic, and of its relationships to other archosaurs. This question was plagued from the beginning by a lack of relevant fossils, an historical burden of confusing taxonomic terms and a rudimentary approach to devising phylogenies. The second dimension concerns the functional and ecological adaptations that differentiated dinosaurs from other archosaurs, a question also marred by lack of phylogenetic clarity and testable biomechanical hypotheses. The third dimension comprises the stratigraphic timing of the origin of dinosaurian groups with respect to each other and to related groups, the question of its synchronicity among various geographic regions, and some of the associated paleoenvironmental circumstances. None of these dimensions alone answers the question of dinosaur origins, and they sometimes provide conflicting implications. Since Dinosauria was named, one or another set of questions has historically dominated academic discussion and research. Paradigms have shifted substantially in recent decades, and current evidence suggests that we are due for more such shifts. I suggest two changes in thinking about the beginning of the “Age of Dinosaurs”: first, the event that we call the (phylogenetic) origin of dinosaurs was trivial compared to the origin of Ornithodira; and second, the “Age of Dinosaurs” proper did not begin until the Jurassic. Re-framing our thinking on these issues will improve our understanding of clade dynamics, timing of macroevolutionary events, and the effects of Triassic climate change on terrestrial vertebrates.

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Articles
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Copyright © The Royal Society of Edinburgh 2013 

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References

10. References

Agassiz, L. 1844. Monographie des poissons fossiles du Vieux Grès Rouge du Système Devonien (Old Red Sandstone) des Iles Britanniques et de Russie. Neuchâtel, Switzerland: Jent & Gassman.Google Scholar
Appleby, R. M., Charig, A. J., Cox, C. B., Kermack, K. A. & Tarlo, L. B. H. 1967. Reptilia. In Harland, W. B., Holland, C. H., House, M. R., Hughes, N. F., Reynolds, A. B., Rudwick, M. J. S., Satterthwaite, G. E., Tarlo, L. B. H. & Willey, E. C. (eds) The Fossil Record. Geological Society, London Special Publications 2, 695731. London: The Geological Society. 820 pp.Google Scholar
Archibald, J. D. 2011. Extinction and Radiation: How the fall of dinosaurs led to the rise of mammals. Baltimore, Maryland: Johns Hopkins University Press.Google Scholar
Archibald, J. D., Clemens, W. A., Padian, K., Rowe, T., Macleod, N., Barrett, P. M., Gale, A., Holroyd, P., Sues, H. D., Arens, N. C., Horner, J. R., Wilson, G. P., Goodwin, M. B., Brochu, C. A., Lofgren, D. L., Hurlbert, S. H., Hartman, J. H., Eberth, D. A., Wignall, P. B., Currie, P. J., Weil, A., Prasad, G. V., Dingus, L., Courtillot, V., Milner, A. C., Milner, A. R., Baipai, S., Ward, D. J. & Sahni, A. 2010. Cretaceous extinctions: multiple cases. Science 328(5981), 973.Google Scholar
Báez, A. M. & Marsicano, C. A. 2001. A heterodontosaurid ornithischian dinosaur from the Upper Triassic of Patagonia. Ameghiniana 38, 271–79.Google Scholar
Bakker, R. T. 1972. Anatomical and ecological evidence of endothermy in dinosaurs. Nature 238 (5359), 8185.Google Scholar
Bakker, R. T. 1975. Dinosaur renaissance. Scientific American 232 (4), 5878.Google Scholar
Bakker, R. T. 1977. Tetrapod mass extinctions: A model of the regulation of speciation rates and immigration by cycles of topographic diversity. In Hallam, A. (ed.) Patterns of Evolution, 439–68. Amsterdam: Elsevier.Google Scholar
Bakker, R. T. 1980. Dinosaur heresy – dinosaur renaissance: why we need endothermic archosaurs for a comprehensive theory of bioenergetic evolution. In Thomas, R. D. K. & Olson, E. C. (eds) A cold look at the warm-blooded dinosaurs, 351462. Boulder, Colorado: Westview Press.Google Scholar
Bakker, R. T. & Galton, P. M. 1974. Dinosaur monophyly and a new class of vertebrates. Nature 248, 168–72.Google Scholar
Bennett, A. F. & Ruben, J. A. 1979. Endothermy and activity in vertebrates. Science 206 (4419), 649–54.CrossRefGoogle ScholarPubMed
Benton, M. J. 1996. On the nonprevalence of competitive replacement in the evolution of tetrapods. In Jablonski, D., Erwin, D. H., & Lipps, J. H. (eds) Evolutionary Paleobiology, 185210. Chicago, Illinois: University of Chicago Press.Google Scholar
Bonaparte, J. F. 1975. Nuevos materiales de Lagosuchus talampayensis Romer (Thecodontia – Pseudosuchia) y su significado en el origen de los Saurischia. Chañares Inferior, Triasico Medio de Argentina. Acta Geologica Lilloana 13 (1), 590.Google Scholar
Bonaparte, J. F. 1982. Faunal replacement in the Triassic of South America. Journal of Vertebrate Paleontology 2 (3), 362–71.Google Scholar
Bonaparte, J. F. 1984. Locomotion in rauisuchid thecodonts. Journal of Vertebrate Paleontology 3 (4), 210–18.Google Scholar
Boulenger, G. A. 1903. On reptilian remains from the Trias of Elgin. Philosophical Transactions of the Royal Society, London B 196, 175–89.Google Scholar
Brinkman, D. 1980. The hind limb step cycle of Caiman sclerops and the mechanics of the crocodile tarsus and metatarsus. Canadian Journal of Zoology 58, 2187–200.Google Scholar
Brusatte, S. L., Benton, M. J., Ruta, M. & Lloyd, G. T. 2008a. Superiority, competition, and opportunism in the evolutionary radiation of dinosaurs. Science 321 (5895), 1485–88.Google Scholar
Brusatte, S. L., Benton, M. J., Ruta, M. & Lloyd, G. T. 2008b. The first 50 Myr of dinosaur evolution: macroevolutionary pattern and morphological disparity. Biology Letters 4 (6), 733–36.Google Scholar
Brusatte, S. L., Nesbitt, S. J., Irmis, R. B., Butler, R. J., Benton, M. J. & Norell, M. A. 2010. The origin and early radiation of dinosaurs. Earth-Science Reviews 101 (1–2), 68100.Google Scholar
Brusatte, S. L., Niedźwiedzki, G. & Butler, R. J. 2011a. Footprints pull origin and diversification of dinosaur stem lineage deep into Early Triassic. Proceedings of the Royal Society, London B 278 (1708), 1107–13.Google Scholar
Brusatte, S. L., Benton, M. J., Lloyd, G. T., Ruta, M. & Wang, S. C. 2011b. Macroevolutionary patterns in the evolutionary radiation of archosaurs (Tetrapoda: Diapsida). Earth and Environmental Science Transactions of the Royal Society of Edinburgh 101 (for 2010), 367–82.Google Scholar
Butler, R. J., Smith, R. M. H. & Norman, D. B. 2007. A primitive ornithischian dinosaur from the Late Triassic of South Africa and the early evolution and diversification of Ornithischia. Proceedings of the Royal Society, London B 274 (1621), 2041–46.Google Scholar
Butler, R. J., Upchurch, P. & Norman, D. B. 2008. The phylogeny of the ornithischian dinosaurs. Journal of Systematic Palaeontology 6 (1), 140.Google Scholar
Camp, C. L. 1923. A classification of the lizards. Bulletin of the American Museum of Natural History 48, 289481.Google Scholar
Camp, C. L. 1936. A new type of small bipedal dinosaur from the Navajo Sandstone of Arizona. University of California Publications in the Geological Sciences 24, 3953.Google Scholar
Carrano, M. T. & Wilson, J. A. 2001. Taxon distributions and the tetrapod track record. Paleobiology 27 (3), 564–82.2.0.CO;2>CrossRefGoogle Scholar
Carroll, R. L. 1990. Vertebrate Paleontology and Evolution. San Francisco, California: W.H. Freeman.Google Scholar
Charig, A. J. 1956. New Triassic Archosaurs from Tanganyika, including Mandasuchus and Teleocrater. PhD Dissertation, University of Cambridge, UK.Google Scholar
Charig, A. J. 1972. The evolution of the archosaur pelvis and hindlimb: an explanation in functional terms. In Joysey, K. A. & Kemp, T. S. (eds) Studies in Vertebrate Evolution, 121–55. London: Oliver & Boyd.Google Scholar
Charig, A. J. 1976a. Subclass Archosauria Cope, 1869. In Kuhn, O. (ed.) Handbuch der Paleoherpetologie 13, 16.Google Scholar
Charig, A. J. 1976b. Thecodontia. In Kuhn, O. (ed.) Handbuch der Paleoherpetologie 13, 710.Google Scholar
Charig, A. J. 1980. Differentiation of lineages among Mesozoic tetrapods. Mémoires de la Société Géologique de France 139, 207–10.Google Scholar
Charig, A. J. 1984. Competition between therapsids and archosaurs during the Triassic Period; a review and synthesis of current theories. In Ferguson, M. W. J. (ed.) The structure, development and evolution of reptiles. Symposia of the Zoological Society of London 52, 597628. London: the Zoological Society.Google Scholar
Charig, A. J., Attridge, J. & Crompton, A. W. 1965. On the origin of the sauropods and the classification of the Saurischia. Proceedings of the Linnean Society of London 176 (2), 197221.Google Scholar
Chatterjee, S. 1982. Phylogeny and classification of thecodontian reptiles. Nature 295 (5847), 317–20.Google Scholar
Colbert, E. H. 1947. Little dinosaurs of Ghost Ranch. Natural History 56, 392–9, 427–28.Google Scholar
Colbert, E. H. 1955. Evolution of the Vertebrates. New York: John Wiley and Sons.Google Scholar
Colbert, E. H. 1981. A primitive ornithischian dinosaur from the Kayenta Formation of Arizona. Museum of Northern Arizona Bulletin 53, 161.Google Scholar
Cope, E. D. 1869. Synopsis of the extinct Batrachia, Reptilia and Aves of North America. Transactions of the American Philosophical Society 14, 1252.Google Scholar
Cruickshank, A. R. I. 1979. The ankle joint in some early archosaurs. South African Journal of Science 75, 168–78.Google Scholar
Darwin, C. 1859. On the Origin of Species by means of Natural Selection. London: John Murray.Google Scholar
Dean, D. R. 1999. Gideon Mantell and the discovery of dinosaurs. New York: Cambridge University Press.Google Scholar
Desmond, A. J. 1976. The hot-blooded dinosaurs: a revolution in palaeontology. London: Blond & Briggs.Google Scholar
Desmond, A. J. 1979. Designing the dinosaur: Richard Owen's response to Robert Edmund Grant. Isis 70, 224–34.Google Scholar
Desmond, A. J. 1982. Archetypes and Ancestors: Palaeontology in Victorian London 1850–1875. London: Blond & Briggs.Google Scholar
Ellenberger, P. 1970. Les niveaux paléontologiques de première apparition des mammifères primordiaux en Afrique du Sud et leur ichnologie. Etablissement de zones stratigraphiques detaillées dans le Storrnberg du Lesotho (Afrique du Sud) (Trias supérieur à Jurassique). In Proceedings and Papers of the Second Gondwana Symposium, IUGS Commission on Stratigraphy, 343–70. Marshalltown, Johannesburg: Geological Society of South Africa.Google Scholar
Fraser, N. 2006. Dawn of the dinosaurs: life in the Triassic. Bloomington: Indiana University Press.Google Scholar
Fraser, N. C. & Sues, H.-D. 1994. In the Shadow of the Dinosaurs: Early Mesozoic tetrapods. New York: Columbia University Press.Google Scholar
Galton, P. M. 1970. Ornithischian dinosaurs and the origin of birds. Evolution 24, 448–62.Google Scholar
Galton, P. M. & Van Heerden, J. 1985. Partial hindlimb of Blikanasaurus cromptoni n. gen. and n. sp., representing a new family of prosauropod dinosaurs from the Upper Triassic of South Africa. Géobios 18 (4), 509–16.Google Scholar
Gauthier, J. A. 1984. A cladistic analysis of the higher systematic categories of the Diapsida. PhD Thesis, Department of Paleontology, University of California, Berkeley, USA.Google Scholar
Gauthier, J. A. 1986. Saurischian monophyly and the origin of birds. Memoirs of the California Academy of Sciences 8, 155.Google Scholar
Haubold, H. 1984. Saurierfährten. Lutherstadt, Wittenberg: A. Ziemsen Verlag.Google Scholar
Haubold, H. 1986. Archosaur footprints at the terrestrial Triassic-Jurassic transition. In Padian, K. (ed.) The Beginning of the Age of Dinosaurs: Faunal change across the Triassic–Jurassic boundary, 189201. New York: Cambridge University Press.Google Scholar
Horner, J. R., de Ricqlès, A. J. & Padian, K. 1999. Variation in skeletochronological indicators of the hadrosaurid dinosaur Hypacrosaurus: implications for age assessment of dinosaurs. Paleobiology 25 (3), 295304.Google Scholar
Horner, J. R., de Ricqlès, & Padian, K. 2000. The bone histology of the hadrosaurid dinosaur Maiasaura peeblesorum: growth dynamics and physiology based on an ontogenetic series of skeletal elements. Journal of Vertebrate Paleontology 20 (1), 115129.Google Scholar
Huene, F. von. 1902. Ubersicht über die Reptilian der Trias. Geologische und Paläontologische Abhandlungen (NF 6) 1, 184.Google Scholar
Huene, F. von. 1911. Beiträge zur Kenntnis und Beurteilung der Parasuchier. Geologische und Paläontologische Abhandlungen NF 10, 65121.Google Scholar
Huene, F. von. 1914. Beiträge zur Geschichte der Archosaurier. Geologische und Paläontologische Abhandlungen NF 13, 153.Google Scholar
Huene, F. von. 1932. Die Fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte. Monographies in Geologie und Paläontologie 4, 1361.Google Scholar
Huene, F. von. 1936. The constitution of the Thecodontia. American Journal of Science (5) 32, 207–17.Google Scholar
Huene, F. von. 1956. Palaeontologie und Phylogenie der niederen Tetrapoden. Jena & Berlin: Gustav Fischer Verlag.Google Scholar
Huxley, T. H. 1859. On the Stagonolepis robertsoni (Agassiz) of the Elgin Sandstones; and on the recently discovered footmarks in the sandstones of Cummingstone. Quarterly Journal of the Geological Society, London 15, 440–60.Google Scholar
Huxley, T. H. 1870. On the classification of the Dinosauria, with observations on the Dinosauria of the Trias. Quarterly Journal of the Geological Society, London 26, 3150.Google Scholar
Huxley, T. H. 1875. On Stagonolepis robertsoni, and on the evolution of the Crocodilia. Quarterly Journal of the Geological Society, London 31, 423–38.Google Scholar
Huxley, T. H. 1877. The crocodilian remains found in the Elgin sandstones, with remarks on the ichnites. Memoirs of the Geological Survey of the United Kingdom, Monograph 3, 158.Google Scholar
Irmis, R. B. 2011. Evaluating hypotheses for the early diversification of dinosaurs. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 101 (for 2010), 397426.CrossRefGoogle Scholar
Irmis, R. B., Nesbitt, S. J., Padian, K., Smith, N. D., Turner, A. H., Woody, D. & Downs, A. 2007a. A Late Triassic dinosauromorph assemblage from New Mexico and the rise of dinosaurs. Science 317 (5836), 358–61.CrossRefGoogle ScholarPubMed
Irmis, R. B., Parker, W. G. & Nesbitt, S. J. 2007b. Early ornithischian dinosaurs: the Triassic record. Historical Biology 19 (1), 322.Google Scholar
Knoll, F., Padian, K. & de Ricqlès, A. 2010. Ontogenetic change and adult body size of the early ornithischian dinosaur Lesothosaurus diagnosticus: implications for basal ornithischian taxonomy. Gondwana Research 17 (1), 171–79.Google Scholar
Köhler, M., Marín-Moratalla, N., Jordana, X. & Aanes, R. 2012. Seasonal bone growth and physiology in endoterms shed light on dinosaur physiology. Nature 487 (7408), 358–61.Google Scholar
Krebs, B. 1963. Bau und Funktion des Tarsus einer Pseudosuchiers des Monte San Giorgio (Kanoton Tessin, Schweiz). Palaontologische Zeitschrift 37, 8895.Google Scholar
Krebs, B. 1965. Ticinosuchus ferox nov. gen. nov. sp., ein neuer Pseudosuchier aus der Trias des Monte San Giorgio. In Kuhn-Schnyder, E. & Peyer, B. (eds) Die Triasfauna der Tessiner Kalkalpen, vol 19. Schweizerische Paläontologische Abhandlungen 81, 1140.Google Scholar
Kubo, T. & Benton, M. J. 2007. Evolution of hindlimb posture in archosaurs: limb stresses in extinct vertebrates. Palaeontology 50 (6), 1519–29.Google Scholar
Langer, M. C., Ezcurra, M. D., Bittencourt, J. S. & Novas, F. E. 2010. The origin and early evolution of dinosaurs. Biological Reviews 85 (1), 55110.Google Scholar
Langer, M. C. & Benton, M. J. 2006. Early dinosaurs: a phylogenetic study. Journal of Systematic Palaeontology 4 (4), 309–58.Google Scholar
MacLeay, W. S. 1821. Horae Entomologicae; or, essays on the annulose animals. London: S. Bagster.Google Scholar
Martin, L. D., Stewart, J. D. & Whetstone, K. 1980. The origin of birds: structure of the tarsus and teeth. The Auk 97, 8693.Google Scholar
Martinez, R. N. & Alcober, O. A. 2009. A basal sauropodomorph (Dinosauria: Saurischia) from the Ischigualasto Formation (Triassic, Carnian) and the early evolution of Sauropodomorpha. PLoS One 4 (2), e4397. doi:10.1371/journal.pone.0004397Google Scholar
Moody, R. T. J. & Naish, D. 2010. Alan Jack Charig (1927–1997): an overview of his academic accomplishments and role in the world of fossil reptile research. In Moody, R. T. J., Buffetaut, E., Naish, D. & Martill, D. M. (eds) Dinosaurs and Other Extinct Saurians: A Historical Perspective. Geological Society, London, Special Publications 343, 89109. Bath, UK; The Geological Society Publishing House.Google Scholar
Nesbitt, S. J. 2011. The early evolution of archosaurs: Relationships and the origin of major clades. Bulletin of the American Museum of Natural History 352, 1292.Google Scholar
Nesbitt, S. J., Irmis, R. B. & Parker, W. G. 2007. A critical re-evaluation of the Late Triassic dinosaur taxa of North America. Journal of Systematic Palaeontology 5 (2), 209–43.Google Scholar
Nesbitt, S. J., Barrett, P. M., Werning, S., Sidor, C. A., Charig, A. J. 2012. The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania. Biology Letters 9 (6), 20120949. http://dx.doi.org/10.1098/rsbl.2012.0949.Google Scholar
Norell, M. A. & Novacek, M. J. 1992. Congruence between superpositional and phylogenetic patterns: comparing cladistic patterns with fossil records. Cladistics 8 (4), 319–37.Google Scholar
Olson, E. C. 1971. Vertebrate Paleozoology. John Wiley and Sons, New York.Google Scholar
Olsen, P. E. 1995. A new approach for recognizing track makers. Geological Society of America Abstracts with Programs 27, 72.Google Scholar
Olsen, P. E., Kent, D. V., Sues, H.-D., Koeberl, C., Huber, H., Montanari, A., Rainforth, E. C., Fowell, S. J., Szajna, M. J. & Hartline, B. W. 2002. Ascent of dinosaurs linked to an iridium anomaly at the Triassic–Jurassic boundary. Science 296 (5571), 1305–07.Google Scholar
Olsen, P. E., Kent, D. V. & Whiteside, J. H. 2011. Implications of the Newark Supergroup-based astrochronology and geomagnetic polarity time scale (Newark-APTS) for the tempo and mode of the early diversification of the Dinosauria. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 101 (for 2010), 201–29.Google Scholar
Olsen, P. E., Shubin, N. H. & Anders, M. H. 1987. New Early Jurassic tetrapod assemblages constrain Triassic–Jurassic tetrapod extinction event. Science 237 (4818), 1025–29.Google Scholar
Olsen, P. E. & Baird, D. 1986. The ichnogenus Atreipus and its significance for Triassic biostratigraphy. In Padian, K. (ed.) The Beginning of the Age of Dinosaurs: Faunal Change Across the Triassic–Jurassic Boundary, 6187. Cambridge, UK: Cambridge University Press.Google Scholar
Olsen, P. E. & Galton, P. M. 1977. Triassic–Jurassic tetrapod extinctions: are they real? Science 197 (4307), 983–86.Google Scholar
Olsen, P. E. & Galton, P. M. 1984. A review of the reptile and amphibian assemblages from the Stormberg of southern Africa, with special emphasis on the footprints and the age of the Stormberg. Palaeontologia Africana 25, 87110.Google Scholar
Olsen, P. E. & Sues, H.-D. 1986. Correlation of continental Late Triassic and Early Jurassic sediments, and patterns of the Triassic–Jurassic tetrapod transition. In Padian, K. (ed.) The Beginning of the Age of Dinosaurs: Faunal Change Across the Triassic–Jurassic Boundary, 321–51. Cambridge, UK: Cambridge University Press.Google Scholar
Ostrom, J. H. 1969. Deinonychus antirrrhopus, an unusual theropod from the Early Cretaceous of Montana. Yale Peabody Museum Bulletin 30, 1165.Google Scholar
Ostrom, J. H. 1970. Terrestrial vertebrates as indicators of Mesozoic climates. North American Paleontological Convention (Chicago, IL, 1969), Proceedings D, 347–76.Google Scholar
Ostrom, J. H. 1973. The ancestry of birds. Nature 242, 136.Google Scholar
Ostrom, J. H. 1975. The origin of birds. Annual Reviews of Earth and Planetary Sciences 3, 5577.Google Scholar
Owen, R. 1842. Report on British fossil reptiles, Part II. Reports of the British Association for the Advancement of Science 1841, 60204.Google Scholar
Owen, R. 1859. Palaeontology. Encylopedia Brittanica, 8th ed., 17, 91176. Edinburgh: A. & C. Black.Google Scholar
Owen, R. 1870. A Monograph of the fossil Reptilia of the Liassic Formations. Part III. Monograph of the Palaeontographical Society 23 (104), 4181, pls 17–20. London: The Palaeontographical Society.Google Scholar
Padian, K. 1983a. Osteology and functional morphology of Dimorphodon macronyx (Buckland) (Pterosauria: Rhamphorhynchoidea), based on new material in the Yale Peabody Museum. Yale Peabody Museum Postilla 189, 144.Google Scholar
Padian, K. 1983b. A functional analysis of flying and walking in pterosaurs. Paleobiology 9 (3), 218–39.Google Scholar
Padian, K. 1984. The origin of pterosaurs. In Reif, W.-E. & Westphal, F. (eds) Third Symposium on Mesozoic Terrestrial Ecosystems: Short papers, 163–68. Tubingen: Attempto.Google Scholar
Padian, K. 1986. Introduction. In Padian, K. (ed.) The Beginning of the Age of Dinosaurs: Faunal Change Across the Triassic-Jurassic Boundary, 17. New York: Cambridge University Press.Google Scholar
Padian, K. 1989. Presence of the dinosaur Scelidosaurus indicates Jurassic age for the Kayenta Formation (Glen Canyon Group, northern Arizona). Geology 17 (5), 438–41.Google Scholar
Padian, K. 1995. Pterosaurs and typology: archetypal physiology in the Owen-Seeley dispute of 1870. In Sarjeant, W. A. S. (ed.) Vertebrate Fossils and the Evolution of Scientific Concepts, 285298. Yverdon, Switzerland: Gordon and Breach.Google Scholar
Padian, K. 1999. Charles Darwin's views of classification in theory and in practice. Systematic Biology 48 (2), 352–64.Google Scholar
Padian, K. 2003. Pterosaur stance and gait, and the interpretation of trackways. Ichnos 10, 115–26.Google Scholar
Padian, K. 2008. Were pterosaur ancestors bipedal or quadrupedal?: Morphometric, functional and phylogenetic considerations. Zitteliana 28B, 2128.Google Scholar
Padian, K. 2012. A bone for all seasons. Nature 487, 310–11.Google Scholar
Padian, K., de Ricqlès, A. J. & Horner, J. R. 2001. Dinosaurian growth rates and bird origins. Nature 412, 405–08.Google Scholar
Padian, K., Horner, J. R. & de Ricqlès, A. 2004. Growth in small dinosaurs and pterosaurs: the evolution of archosaurian growth strategies. Journal of Vertebrate Paleontology 24 (3), 555–71.Google Scholar
Padian, K., Li, C. & Pchelnikova, J. 2010. The trackmaker of Apatopus (Late Triassic, North America): implications for the evolution of archosaur stance and gait. Palaeontology 53 (1), 175–89.Google Scholar
Padian, K. & Horner, J. R. 2002. Typology versus transformation in the origin of birds. Trends in Ecology and Evolution 17 (3), 120–24.Google Scholar
Padian, K. & Olsen, P. E. 1984. The track of Pteraichnus: not pterosaurian, but crocodilian. Journal of Paleontology 58 (1), 178–84.Google Scholar
Parker, W. G., Irmis, R. B., Nesbitt, S. J., Martz, J. W. & Browne, L. S. 2005. The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs. Proceedings of the Royal Society, London B 272, 963–69.Google Scholar
Parrish, J. M. 1986. Locomotor adaptations in the hindlimb and pelvis of the Thecodontia. Hunteria 1 (2), 235.Google Scholar
Raup, D. M. 1991. Extinction: Bad Genes or Bad Luck? New York: W. W. Norton.Google Scholar
Ricqlès, A. J. de, Padian, K., Horner, J. R. & Francillon-Viellot, H. 2000. Paleohistology of the bones of pterosaurs (Reptilia: Archosauria): anatomy, ontogeny, and biomechanical implications. Zoological Journal of the Linnean Society 129 (3), 349–85.Google Scholar
Ricqlès, A. J. de, Padian, K. & Horner, J. R. 2003. On the bone histology of some Triassic pseudosuchian archosaurs and related taxa. Annales de Paleontologie 89 (2), 67101.Google Scholar
Ricqlès, A. J. de, Padian, K., Knoll, F. & Horner, J. R. 2008. On the origin of rapid growth rates in archosaurs and their ancient relatives: complementary histological studies on Triassic archosauriforms and the problem of a “phylogenetic signal” in bone histology. Annales de Paleontologie 94 (2), 5776.Google Scholar
Romer, A. S. 1945. Vertebrate Paleontology (2nd ed.). Chicago: University of Chicago Press.Google Scholar
Romer, A. S. 1966. Vertebrate Paleontology (3rd ed.). Chicago: University of Chicago Press.Google Scholar
Romer, A. S. 1968. Notes and comments on Vertebrate Paleontology. Chicago: University of Chicago Press.Google Scholar
Romer, A. S. 1971. The Chañares (Argentina) Triassic reptile fauna. X. Two new but incompletely known long-limbed pseudosuchians. Breviora 378, 110.Google Scholar
Romer, A. S. 1972. The Chañares (Argentina) Triassic reptile fauna. XV. Further remains of the thecodonts Lagerpeton and Lagosuchus. Breviora 394, 17.Google Scholar
Rowe, T. B., Sues, H.-D. & Reisz, R. R. 2011. Dispersal and diversity in the earliest North American sauropodomorph dinosaurs, with a description of a new taxon. Proceedings of the Royal Society, London B 278 (1708), 1044–53.Google Scholar
Rowe, T. & Gauthier, J. 1990. Ceratosauria. In Weishampel, D. B., Dodson, P. & Osmólska, H. (eds) The Dinosauria, 151168. Berkeley: University of California Press.Google Scholar
Rüpke, N. A. 1994. Richard Owen: Victorian Naturalist. New Haven, Connecticut: Yale University Press.Google Scholar
Sander, M. 1999. Life history of Tendaguru sauropods as inferred from long bone histology. Mitteilungen der Museum der Naturkunde Berlin, Geowissenschaftliches Reihe 2, 103–12.Google Scholar
Sander, M. & Klein, N. 2005. Developmental plasticity in the life history of a prosauropod dinosaur. Science 310 (5755), 1800–02.Google Scholar
Schaeffer, B. 1941. The morphological and functional evolution of the tarsus in amphibians and reptiles. Bulletin of the American Museum of Natural History 78, 398472.Google Scholar
Seeley, H. G. 1887. On the classification of the fossil animals commonly named Dinosauria. Proceedings of the Royal Society, London 43, 165–71.Google Scholar
Seeley, H. G. 1892. Researches on the structure, organization, and classification of the fossil Reptilia. VII. Further observations on Pareiasaurus. Philosophical Transactions of the Royal Society, London B 183, 119–51.Google Scholar
Seeley, H. G. 1901. Dragons of the Air. New York: Appleton.Google Scholar
Sereno, P. C. 1986. Phylogeny of the bird-hipped dinosaurs (Order Ornithischia). National Geographic Research 2 (2), 234–56.Google Scholar
Sereno, P. C. 1991. Basal archosaurs: phylogenetic relationships and functional implications. Journal of Vertebrate Paleontology 11 (Supp 004), 151.Google Scholar
Sereno, P. C. & Arcucci, A. B. 1994. Dinosaurian precursors from the Middle Triassic of Argentina: Lagerpeton chanarensis. Journal of Vertebrate Paleontology 13 (4), 385–99.Google Scholar
Shoemaker, E. M. 1983. Asteroid and comet bombardment of the earth. Annual Review of Earth and Planetary Sciences 11, 461–94.Google Scholar
Sues, H.-D. & Fraser, N. C. 2010. Triassic life on land: the great transition. New York: Columbia University Press.Google Scholar
Talbot, M. 1911. Podokesaurus holyokensis, a new dinosaur from the Triassic of the Connecticut Valley. American Journal of Science 31 (4), 469–79.Google Scholar
Thomas, R. D. K. & Olson, E.C. (eds) 1980. A cold look at the warm-blooded dinosaurs. Boulder, Colorado: Westview Press.Google Scholar
Thomson, K. S. 2009. The young Charles Darwin. New Haven: Yale University Press.Google Scholar
Thulborn, R. A. 1982. Significance of ankle structures in archosaur phylogeny, Nature 299, 657 (14 October 1982).Google Scholar
Thulborn, T. 2006. On the tracks of the earliest dinosaurs: implications for the hypothesis of dinosaurian monophyly, Alcheringa 30 (2), 273311.Google Scholar
Torrens, H. S. 1992. When did the dinosaur get its name? New Scientist April 4, 4044.Google Scholar
Upchurch, P., Hunn, C. A. & Norman, D. B. 2002. An analysis of dinosaurian biogeography: evidence for the existence of vicariance and dispersal patterns caused by geological events. Proceedings of the Royal Society, London B 269 (1491), 613–21.Google Scholar
Walker, A. D. 1964. Triassic reptiles from the Elgin area: Ornithosuchus and the origin of carnosaurs. Philosophical Transactions of the Royal Society, London B 248, 53134.Google Scholar
Wang, S. C. & Dodson, P. 2006. Estimating the diversity of dinosaurs. Proceedings of the National Academy of Sciences (USA) 103 (37), 13601–05.Google Scholar
Watson, D. M. S. 1917. A sketch-classification of the pre-Jurassic tetrapod vertebrates. Proceedings of the Zoological Society of London 1917, 167–86.Google Scholar
Welles, S. P. 1954. New Jurassic dinosaur from the Kayenta Formation of Arizona. Geological Society of America Bulletin 65, 591–98.Google Scholar
Werning, S., Irmis, R., Smith, N., Turner, A. & Padian, K. 2011. Archosauromorph bone histology reveals early evolution of elevated growth and metabolic rates. Society of Vertebrate Paleontology, 71st annual meeting, Program and Abstracts, 213A.Google Scholar
Zittel, K. A. von. 1887–1890. Handbuch der Palaeontologie. 1. Abteilung: Palaeozoologie. Munich & Leipzig: R. Oldenbourg.Google Scholar