590
Views
6
CrossRef citations to date
0
Altmetric
Articles

New Specimens of Scutellosaurus Lawleri Colbert, 1981, from the Lower Jurassic Kayenta Formation in Arizona Elucidate the Early Evolution of Thyreophoran Dinosaurs

ORCID Icon &
Article: e1791894 | Received 13 May 2019, Accepted 27 May 2020, Published online: 05 Oct 2020

LITERATURE CITED

  • Agnolín, F. L., and S. Rozadilla. 2017. Phylogenetic reassessment of Pisanosaurus mertii Casamiquela, 1967, a basal dinosauriform from the Late Triassic of Argentina. Journal of Systematic Palaeontology 16:853–879.
  • Apaldetti, C., R. N. Martínez, O. A. Alcobar, and D. Pol. 2011. A new basal sauropodomorph (Dinosauria: Saurischia) from Quebrada del Barro Formation (Marayes-El Carrizal Basin), northwestern Argentina. PLoS ONE 6:e26964.
  • Archibald, J. D., W. A. Clemens, K. Padian, T. Rowe, N. Macleod, P. M. Barrett, A. Gale, P. Holroyd, H.-D. Sues, N. C. Arens, J. R. Horner, G. P. Wilson, M. B. Goodwin, C. A. Brochu, D. L. Lofgren, S. H. Hurlbert, J. H. Hartman, D. A. Eberth, P. B. Wignall, P. J. Currie, A. Weil, G. V. R. Prasad, L. Dingus, V. Courtillot, A. Milner, A. Milner, S. Bajpai, D. J. Ward, and A. Sahni. 2010. Cretaceous extinctions: multiple causes. Science 328:973.
  • Attridge, J., A. J. Crompton, and F. A. Jenkins. 1985. The southern African Liassic prosauropod Massospondylus discovered in North America. Journal of Vertebrate Paleontology 5:128–132.
  • Báez, A. M., and C. A. Marsicano. 2001. A heterodontosaurid ornithischian dinosaur from the Upper Triassic of Patagonia. Ameghiniana 38:271–279.
  • Baron, M. B. 2017. Pisanosaurus mertii and the Triassic ornithischian crisis: could phylogeny offer a solution? Historical Biology 31:967–981.
  • Baron, M. B., D. B. Norman, and P. M. Barrett. 2017a. A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature 543:501–506.
  • Baron, M. B., D. B. Norman, and P. M. Barrett. 2017b. Postcranial anatomy of Lesothosaurus diagnosticus (Dinosauria: Ornithischia) from the Lower Jurassic of southern Africa: implications for basal ornithischian taxonomy and systematics. Zoological Journal of the Linnean Society 179:125–168.
  • Barrett, P. M. 2009. A new basal sauropodomorph dinosaur from the Upper Elliot Formation (Lower Jurassic) of South Africa. Journal of Vertebrate Paleontology 29:1032–1045.
  • Barrett, P. M., R. J. Butler, R. Mundil, T. M. Scheyer, R. B. Irmis, and M. R. Sánchez-Villagra. 2014. A palaeoequatorial ornithischian and new constraints on early dinosaur diversification. Proceedings of the Royal Society of London B 281:2014–1147.
  • Benton, M. J. 1987. Progress and competition in macroevolution. Biological Reviews 62:305–338.
  • Blackburn, T. J., P. E. Olsen, S. A. Bowring, N. M. McLean, D. V. Kent, J. Puffer, G. McHone, E. T. Rasbury, and M. Et-Touhami. 2013. Zircon U-Pb geochronology links the end-Triassic extinction with the Central Atlantic Magmatic Province. Science 340:941–945.
  • Bonaparte, J. F. 1976. Pisanosaurus mertii Casamiquela and the origin of the Ornithischia. Journal of Paleontology 50:808–820.
  • Bordy, E. M., M. Abrahams, G. R. Sharman, P. A. Viglietti, R. B. J. Benson, B. W. McPhee, P. M. Barrett, L. Sciscio, D. Condon, R. Mundil, Z. Rademan, Z. Jinnah, J. M. Clark, C. A. Suarez, K. E. J. Chapelle, and J. N. Choiniere. 2020. A chronostratigraphic framework for the upper Stormberg Group: Implications for the Triassic–Jurassic boundary in southern Africa. Earth-Science Reviews 203:103120.
  • Boyd, C. A. 2015. The systematic relationships and biogeographic history of ornithischian dinosaurs. PeerJ 3:e1523.
  • Breeden, B. T., III. 2018. Fragmentary specimens provide evidence for hidden taxonomic diversity of ornithischian dinosaurs within the Lower Jurassic Kayenta Formation (northeastern Arizona, U.S.A.). Journal of Vertebrate Paleontology, Program and Abstracts, 2018:96.
  • Brochu, C. A. 1996. Closure of neurocentral sutures during crocodilian ontogeny: implications for maturity assessment in fossil archosaurs. Journal of Vertebrate Paleontology 16:49–62.
  • Brown, B. 1908. The Ankylosauridae, a new family of armored dinosaurs from the Upper Cretaceous. Bulletin of the American Museum of Natural History 24:187–201.
  • Buchholz, P. W. 2002. Phylogeny and biogeography of basal Ornithischia; pp. 18–34 in D. E. Brown (ed.), The Mesozoic in Wyoming. Tate Geological Museum, Casper College, Casper, Wyoming.
  • Brusatte, S. L., M. J. Benton, M. Ruta, and G. T. Lloyd. 2008. Superiority, competition, and opportunism in the evolutionary radiation of dinosaurs. Science 321:1485–1488.
  • Brusatte, S. L., S. J. Nesbitt, R. B. Irmis, R. J. Butler, M. J. Benton, and M. A Norell. 2010. The origin and early radiation of dinosaurs. Earth-Science Reviews 101:68–100.
  • Burns, M. S., and P. J. Currie. 2014. External and internal structure of ankylosaur (Dinosauria, Ornithischia) osteoderms and their systematic relevance, Journal of Vertebrate Paleontology. 34:835–851.
  • Butler, R. J. 2005. The “fabrosaurid” ornithischian dinosaurs of the Upper Elliot Formation (Lower Jurassic) of South Africa and Lesotho. Zoological Journal of the Linnean Society 145:175–218.
  • Butler, R. J. 2010. The anatomy of the basal ornithischian dinosaur Eocursor parvus from the Lower Elliot Formation (Late Triassic) of South Africa. Zoological Journal of the Linnean Society 160:648–684.
  • Butler, R. J., R. M. H. Smith, and D. B. Norman. 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 of London B 274:2041–2046.
  • Butler, R. J., P. Upchurch, and D. B. Norman. 2008. The phylogeny of the ornithischian dinosaurs. Journal of Systematic Palaeontology 6:1–40.
  • Butler, R. J., P. M. Galton, L. B. Porro, L. M. Chiappe, D. M. Henderson, and G. M. Erickson. 2010. Lower limits of ornithischian dinosaur body size inferred from a new Upper Jurassic heterodontosaurid from North America. Proceedings of the Royal Society of London B 277:375–381.
  • Butler, R. J., J. Liyong, C. Jun, and P. Godefroit. 2011. The postcranial osteology and phylogenetic position of the small ornithischian dinosaur Changchunsaurus parvus from the Quantou Formation (Cretaceous: Aptian–Cenomanian) of Jilin Province, north-eastern China. Palaeontology 54:667–683.
  • Camp, C. L. 1936. A new type of small bipedal dinosaur from the Navajo Sandstone of Arizona. University of California Publications, Bulletin of the Department of Geological Sciences 24:39–56.
  • Carpenter, K. 2001. Phylogenetic analysis of the Ankylosauria; pp. 455–483 in K. Carpenter (ed.), The Armored Dinosaurs. Indiana University Press, Bloomington, Indiana.
  • Carpenter, K., C. A. Miles, and K. Cloward. 2001. New primitive stegosaur from the Morrison Formation, Wyoming; pp. 55–75 in K. Carpenter (ed.), The Armored Dinosaurs. Indiana University Press, Bloomington, Indiana.
  • Casamiquela, R. M. 1967. Un nuevo dinosaurio ornithisquio Triasico (Pisanosaurus mertii; Ornithopoda) de la Formacion Ischigualasto, Argentina. Ameghiniana 4:47–64.
  • Chatterjee, S. 1984. A new ornithischian dinosaur from the Triassic of North America. Naturwissenschaften 71:630–631.
  • Clark, J. M., and D. E. Fastovsky. 1986. Vertebrate biostratigraphy of the Glen Canyon Group in northern Arizona; pp. 285–301 in K. Padian (ed.), The Beginning of the Age of Dinosaurs. Cambridge University Press, Cambridge.
  • Colbert, E. H. 1981. A primitive ornithischian dinosaur from the Kayenta Formation of Arizona. Museum of Northern Arizona Bulletin Series 53:1–60.
  • Crompton, A. W, and A. J. Charig. 1962. A new ornithischian from the Upper Triassic of South Africa. Nature 196:1074–1077.
  • Dacke, C. G., R. M. Elsey, P. L. Trosclair, III, T. Sugiyama, J. G. Nevarez, and M. H. Schweitzer. 2015. Alligator osteoderms as a source of labile calcium for eggshell formation. Journal of Zoology 297:255–264.
  • Davis, G. H., and A. P. Bump. 2009. Structural geologic evolution of the Colorado Plateau: pp. 99–124 in S. M. Kay, V. A. Ramos, and W. R. Dickinson (eds.), Back-bone of the Americas: Shallow Subduction, Plateau Uplift, and Ridge and Terrane Collision: Geological Society of America Memoir 204.
  • de Queiroz, K., and J. Gauthier. 1992. Phylogenetic taxonomy. Annual Review of Ecology and Systematics 23:449–480.
  • Dieudonné, P. -E., P. Cruzado-Caballero, P. Godefroit, and T. Tortosa. 2020. A new phylogeny of cerapodan dinosaurs. Historical Biology. DOI: 10.1080/08912963.2020.1793979.
  • Dong, Z. 2001. Primitive armored dinosaur from the Lufeng Basin, China; pp. 237–242 in D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Bloomington, Indiana.
  • Dutton, C. E. 1882. Tertiary history of the Grand Cañon district, with atlas. Monographs of the United States Geological Survey 2:1–264.
  • Dzik, J. 2003. A beaked herbivorous archosaur with dinosaur affinities from the early Late Triassic of Poland. Journal of Vertebrate Paleontology 23:556–574.
  • Fang, X. S., Q. Q. Pang, L. W. Lu, Z. X. Zhang, S. G. Pan, Y. M. Wang, X. K. Li, and Z. W. Cheng. 2000. Division of lower, middle and upper Jurassic in Lufeng Area, Yunnan. Proceedings of the Third National Stratigraphic Conference of China:208–214.
  • Galton, P. M. 1974. The ornithischian dinosaur Hypsilophodon from the Wealden of the Isle of Wight. Bulletin of the British Museum (Natural History), Geology 25:1–152.
  • Galton, P. M. 2014. Notes on the postcranial anatomy of the heterodontosaurid dinosaur Heterodontosaurus tucki, a basal ornithischian from the Lower Jurassic of South Africa. Revue de Paléobiologie, Genève 33:97–141.
  • Galton, P. M., and P. Upchurch. 2004. Prosauropoda; pp. 232–258 in D. B. Weishampel, P. Dodson, and H. Osmólska (eds.), The Dinosauria, second edition. University of California Press, Berkeley, California.
  • Gauthier, J. 1986. Saurischian monophyly and the origin of birds. Memoirs of the California Academy of Sciences 8:1–55.
  • Gilmore, C. W. 1931. A new species of troodont dinosaur from the Lance Formation of Wyoming. Proceedings of the United States National Museum 79:1–6.
  • Goloboff, P., Farris, J., and Nixon, K. 2008, TNT: a free program for phylogenetic Analysis. Cladistics 24: 774–786.
  • Griffin, C. T. 2018. Developmental patterns and variation among early theropods. Journal of Anatomy 232: 604–640.
  • Griffin, C. T. 2019. Large neotheropods from the Upper Triassic of North America and the early evolution of large theropod body sizes. Journal of Paleontology 93:1010–1030.
  • Griffin, C. T., and S. J. Nesbitt. 2016. Anomalously high variation in growth is ancestral for dinosaurs but lost in birds. Proceedings of the National Academy of Sciences of the United States of America 113:14757–14762.
  • Harshbarger, J. W., C. A. Repenning, and J. H. Irwin. 1957. Stratigraphy of the uppermost Triassic and the Jurassic rocks of the Navajo country. United States Geological Survey Professional Paper 291:1–74.
  • Haubold, H. 1990. Ein neuer Dinosaurier (Ornithischia, Thyreophora) aus dem unteren Jura des nördlichen Mitteleuropa. Revue de Paléobiologie 9:149–177. [ German]
  • Hayashi, S., K. Carpenter, and D. Suzuki. 2009. Different growth patterns between the skeleton and osteoderms of Stegosaurus (Ornithischia: Thyreophora). Journal of Vertebrate Paleontology 29:123–131.
  • Hayashi, S., K. Carpenter, T. M. Scheyer, M. Watabe, and D. Suzuki. 2010. Function and evolution of ankylosaur dermal armor. Acta Palaeontologica Polonica 55:213–228.
  • Heckert, A. B. 2002. A revision of the Upper Triassic ornithischian dinosaur Revueltosaurus, with a description of a new species. New Mexico Museum of Natural History and Science Bulletin 21: 253–268.
  • Holtz, T. R., R. E. Chapman, and M. C. Lamanna. 2004. Mesozoic biogeography of Dinosauria; pp. 627–642 in D. B. Weishampel, P. Dodson, and H. Osmólska (eds.), The Dinosauria, second edition. University of California Press, Berkeley, California.
  • Hunt, A. P. 1989. A new ?ornithischian dinosaur from the Bull Canyon Formation (Upper Triassic) of east-central New Mexico; pp. 355–358 in S. G. Lucas and A. P. Hunt (eds.), Dawn of the Age of Dinosaurs in the American Southwest. New Mexico Museum of Natural History, Albuquerque, New Mexico.
  • Hunt, A. P., and S. G. Lucas. 1994. Ornithischian dinosaurs from the Upper Triassic of the United States; pp. 227–241 in N. C. Fraser and H.-D. Sues (eds.), In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods. Cambridge University Press, Cambridge, U.K.
  • Irmis, R. B. 2007. Axial skeleton ontogeny in the Parasuchia (Archosauria: Pseudosuchia) and its implications for ontogenetic determination in archosaurs. Zoological Journal of the Linnean Society 131:169–197.
  • Irmis, R. B., W. G. Parker, S. J. Nesbitt, and J. Liu. 2007. Early ornithischian dinosaurs: the Triassic record. Historical Biology 19:3–22.
  • Jenkins, F. A., Jr. and D. M. Walsh. 1993. An Early Jurassic caecilian with limbs. Nature 365:246–250.
  • Jenkins, Jr, F. A., D. M. Walsh, and R. L. Carroll. 2007. Anatomy of Eocaecilia micropodia, a limbed caecilian of the Early Jurassic. Bulletin of the Museum of Comparative Zoology 158:285–366.
  • Langer, M. C. 2004. Basal Saurischia; pp. 25–46 in D. B. Weishampel, P. Dodson, and H. Osmólska (eds.), The Dinosauria, second edition. University of California Press, Berkeley, California.
  • Langer, M. C., and M. J. Benton. 2006. Early dinosaurs: a phylogenetic study. Journal of Systematic Paleontology 4:309–358.
  • Langer, M. C., M. D. Ezcurra, J. S. Bittencourt, and F. E. Novas. 2010. The origin and early evolution of dinosaurs. Biological Reviews 85:55–110.
  • Langer, M. C., M. D. Ezcurra, O. W. Rauhut, M. J. Benton, F. Knoll, B. W. McPhee, F. E. Novas, D. Pol, and S. L. Brusatte. 2017. Untangling the dinosaur family tree. Nature 551:E1–E5.
  • Lucas, S. G., and A. B. Heckert. 2001. Theropod dinosaurs and the Early Jurassic age of the Moenave Formation, Arizona-Utah, USA. Neues Jahrbuch für Geologie und Paläontologie Monatschefte 2001:435–448.
  • Maddison, W. P., and D. R. Maddison. 2015. Mesquite: a modular system for evolutionary analysis, version 3.04. Available at mesquiteproject.org. Accessed July 19, 2018.
  • Maidment, S. C. R., and P. M. Barrett. 2011. The locomotor musculature of basal ornithischian dinosaurs. Journal of Vertebrate Paleontology 31:1265–1291.
  • Maidment, S. C. R., and P. M. Barrett. 2014. Osteological correlates for quadrupedality in ornithischian dinosaurs. Acta Paleontologica Polonica 59:53–70.
  • Maidment, S. C. R., D. M. Henderson, and P. M. Barrett. 2014. What drove reversions to quadrupedality in ornithischian dinosaurs? Testing hypotheses using center of mass modeling. Naturwissenschaften 101:989–1001.
  • Maidment, S. C. R., and L. B. Porro. 2010. Homology of the palpebral and origin of supraorbital ossifications in ornithischian dinosaurs. Lethaia 43:95–111.
  • Main, R. P., A. de Ricqles, 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.
  • Mao, L., L. Xing, J. Zhang, T. Wang, and D. Wang. 2019. Revisiting the world famous Lufeng Formation dinosaur fauna: new approaches to old problems. Historical Biology 32:1062–1070.
  • Marsh, A. D. 2018. Anatomy, systematics, and geochronology of Dilophosaurus wetherilli; pp. 10–11 in T. J. Thomson, J. Harris, A. R. C. Milner, and J. Kirkland (eds.), Western Association of Vertebrate Paleontology Annual Meeting: Program with Abstracts. PaleoBios 35 Supplement.
  • Marsh, A. D., and T. Rowe. 2018. Anatomy and systematics of the sauropodomorph Sarahsaurus aurifontanalis from the Early Jurassic Kayenta Formation. PLoS ONE 13:e0204007.
  • Marsh, A., and T. Rowe. 2020. A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona. Journal of Paleontology, 94 Memoir 78:1–103. doi:10.1017/jpa.2020.14.
  • Marsh, A. D., W. G. Parker, M. C. Langer, and S. J. Nesbitt. 2019. Redescription of the holotype specimen of Chindesaurus byransmalli Long and Murry, 1995 (Dinosauria, Theropoda), from Petrified Forest National Park, Arizona. Journal of Vertebrate Paleontology 39:e1645682.
  • Marsh, A. D., T. Rowe, A. Simonetti, D. Stockli, and L. Stockli. 2014. The age of the Kayenta Formation of northeastern Arizona: overcoming the challenges of dating fossil bone. Journal of Vertebrate Paleontology, Program and Abstracts, 2014:178.
  • Marsh, O. C. 1889. Notice of gigantic horned Dinosauria from the Cretaceous. American Journal of Science, Series 3 38:173–175.
  • Martill, D. M., D. J. Batten, D. K. Loydell. 2000. A new specimen of the thyreophoran dinosaur cf. Scelidosaurus with soft tissue preservation. Palaeontology 43:549–559.
  • Martínez, R. N. 2009. Adeopapposaurus mognai, gen. et sp. nov. (Dinosauria: Sauropodomorpha), with comments on adaptations of basal Sauropodomorpha. Journal of Vertebrate Paleontology 29:142–164.
  • Marzoli, A., P. R. Renne, E. M. Piccirillo, M. Ernesto, G. Bellieni, and A. de Min. 1999. Extensive 200-million-year-old continental flood basalts of the Central Atlantic Magmatic Province. Science 284:616–618.
  • McPhee, B. W., E. M. Bordy, L. Sciscio, and J. N. Choiniere. 2017. The sauropodomorph biostratigraphy of the Elliot Formation of southern Africa: tracking the evolution of Sauropodomorpha across the Triassic–Jurassic boundary. Acta Palaeontologica Polonica 62:441–465.
  • McPhee, B. W., Yates, A. M., Choiniere J. N., and Abdala F. 2014. The complete anatomy and phylogenetic relationships of Antetonitrus ingenipes (Sauropodiformes, Dinosauria): implications for the origins of Sauropoda. Zoological Journal of the Linnean Society 171:151–205.
  • Nesbitt, S. J. 2011. The early evolution of archosaurs. Bulletin of the American Museum of Natural History 352:1–292.
  • Nesbitt, S. J., R. B. Irmis, and W. G. Parker. 2007. A critical re-evaluation of the Late Triassic dinosaur taxa of North America. Journal of Systematic Palaeontology 5:209–243.
  • Nesbitt, S. J., N. D. Smith, R. B. Irmis, A. H. Turner, A. Downs, and M. A. Norell. 2009. A complete skeleton of a Late Triassic saurischian and the early evolution of dinosaurs. Science 326:1530–1533.
  • Nopcsa, F. 1915. Die dinosaurier der siebenbürgischen landesteile ungarns. Mitteilungen aus dem Jahrbuche der Königlich Ungarischen Geologischen Anstalt 21:1–26.
  • Norman, D. B. 1984. A systematic reappraisal of the reptile order Ornithischia; pp. 157–162 in W. E. Reif, and F. Westphal (eds.), Third Symposium on Mesozoic Terrestrial Ecosystems, Short Papers. Attempto Verlag, Tübingen.
  • Norman, D. B. 2020a. Scelidosaurus harrisonii from the Early Jurassic of Dorset, England: cranial anatomy. Zoological Journal of the Linnean Society 188:1–81.
  • Norman, D. B. 2020b. Scelidosaurus harrisonii from the Early Jurassic of Dorset, England: postcranial skeleton. Zoological Journal of the Linnean Society 189:47–157.
  • Norman, D. B. 2020c. Scelidosaurus harrisonii from the Early Jurassic of Dorset, England: the dermal skeleton. Zoological Journal of the Linnean Society. doi: 10.1093/zoolinnean/zlz085.
  • Norman, D. B., R. J. Butler, and S. C. R. Maidment. 2007. Reconsidering the status and affinities of the ornithischian dinosaur Tatisaurus oehleri Simmons, 1965. Zoological Journal of the Linnean Society 150:865–874.
  • Norman, D. B., A. W. Crompton, R. J. Butler, L. B. Porro, and A. J. Charig. 2011. The Lower Jurassic ornithischian dinosaur Heterodontosaurus tucki Crompton & Charig, 1962: cranial anatomy, functional morphology, taxonomy, and relationships. Zoological Journal of the Linnean Society 163:182–276.
  • Norman, D. B., L. M. Witmer, and D. B. Weishampel. 2004. Basal Thyreophora; pp. 335–342 in D. B. Weishampel, P. Dodson, and H. Osmólska (eds.), The Dinosauria, second edition. University of California Press, Berkeley, California.
  • Ohashi, T., and P. M. Barrett. 2009. A new ornithischian dinosaur from the Lower Cretaceous Kuwajima Formation of Japan. Journal of Vertebrate Paleontology 29:748–757.
  • Olsen, P. E., D. V. Kent, and J. H. Whiteside. 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 101:201–229.
  • Owen, R. 1842. Report on British fossil reptiles. Report of the British Association for the Advancement of Science 11:60–204.
  • Owen, R. 1861. Monograph on the Fossil Reptilia of the Liassic formations. Part 1. A monograph of a fossil dinosaur (Scelidosaurus harrisonii Owen) of the Lower Lias. Palaeontographical Society Monograph 13:1–14.
  • Owen, R. 1863. A monograph on the Fossil Reptilia of the Liassic formations. Part 2. A monograph of a fossil dinosaur (Scelidosaurus harrisonii Owen) of the Lower Lias. Palaeontographical Society Monograph 2:1–26.
  • Padian, K. 1989. Presence of the dinosaur Scelidosaurus indicates Jurassic age for the Kayenta Formation (Glen Canyon Group, northern Arizona). Geology 17:438–441.
  • Padian, K., J. R. Horner, and A. de Ricqlès. 2004. Growth in small dinosaurs and pterosaurs: the evolution of archosaurian growth strategies. Journal of Vertebrate Paleontology 24:555–571.
  • Parker, W. G., R. B. Irmis, S. J. Nesbitt, J. W. Martz, and L. S. Browne. 2005. The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs. Proceedings of the Royal Society of London B 272:963–969.
  • Parks, W. A. 1922. Parasaurolophus walkeri, a new genus and species of crested trachodont dinosaur. University of Toronto Studies (Geological Series) 13:1–32.
  • Porro, L. B., L. M. Witmer, and P. M. Barrett. 2015. Digital preparation and osteology of the skull of Lesothosaurus diagnosticus (Ornithischia: Dinosauria). PeerJ 3:e1494.
  • Raath, M. A. 1980. The theropod dinosaur Syntarsus (Saurischia: Podokesauridae) discovered in South Africa. South African Journal of Science 76: 375–376.
  • Raven, T. J., and S. C. R. Maidment. 2017. A new phylogeny of Stegosauria (Dinosauria, Ornithischia). Palaeontology 60:401–408.
  • Raven, T. J., and S. C. R. Maidment. 2018. The systematic position of the enigmatic thyreophoran dinosaur Paranthodon africanus, and the use of basal exemplifiers in phylogenetic analysis. PeerJ 6:e4529.
  • Rosenbaum, J. N., and K. Padian. 2000. New material of the basal thyreophoran Scutellosaurus lawleri from the Kayenta Formation (Lower Jurassic) of Arizona. PaleoBios 20:13–23.
  • Rowe, T. 1989. A new species of the theropod Syntarsus from the Early Jurassic Kayenta Formation of Arizona. Journal of Vertebrae Paleontology 9:125–136.
  • Rowe, T. B., H.-D. Sues, and R. R. Reisz. 2010. Dispersal and diversity in the earliest North American sauropodomorph dinosaurs, with a description of a new taxon. Proceedings of the Royal Society B 278:1044–1053.
  • Santa Luca, A. P. 1980. The postcranial skeleton of Heterodontosaurus tucki (Reptilia, Ornithischia) from the Stormberg of South Africa. Annals of the South African Museum 79:159–211.
  • Schaltegger, U., J. Guex, A. Bartolini, B. Schoene, and M. Ovtcharova. 2008. Precise U–Pb age constraints for end-Triassic mass extinction, its correlation to volcanism and Hettangian post-extinction recovery. Earth and Planetary Science Letters 267:266–275.
  • Scheyer, T., and P. M. Sander. 2004. Histology of ankylosaur osteoderms: implications for systematics and function. Journal of Vertebrate Paleontology. 24:874–893.
  • Seeley, H. G. 1887. On the classification of the fossil animals commonly named Dinosauria. Proceedings of the Royal Society of London 43:165–171.
  • Sereno, P. C. 1984. The phylogeny of Ornithischia; a reappraisal; pp. 219–226 in W. E. Reif and F. Westphal (eds.), Third Symposium on Mesozoic Terrestrial Ecosystems, Short Papers. Attempto Verlag, Tübingen.
  • Sereno, P. C. 1986. Phylogeny of the bird-hipped dinosaurs (Order Ornithischia). National Geographic Research 2:234–256.
  • Sereno, P. C. 1991. Lesothosaurus, “fabrosaurids,” and the early evolution of Ornithischia. Journal of Vertebrate Paleontology 11:168–197.
  • Sereno, P. C. 1997. The origin and evolution of dinosaurs. Annual Review of Earth and Plaentary Sciences 25:435–489.
  • Sereno, P. C. 1998. A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 210:41–83.
  • Sereno, P. C. 1999. The evolution of dinosaurs. Science 284:2137–2147.
  • Sereno, P. C. 2012. Taxonomy, morphology, masticatory function, and phylogeny of heterodontosaurid dinosaurs. ZooKeys 226:1–225.
  • Sertich, J. J. W., and M. A. Loewen. 2010. A new basal sauropodomorph dinosaur from the Lower Jurassic Navajo Sandstone of southern Utah. PLoS ONE 5:e9789.
  • Simmons, D. J. 1965. The non-therapsid reptiles of the Lufeng Basin, Yunnan, China. Fieldiana Geology 15:1–93.
  • Smith, N. D., Makovicky, P. J., Hammer, W. R., and Currie, P. J. 2007. Osteology of Cryolophosaurus ellioti (Dinosauria: Theropoda) from the Early Jurassic of Antarctica and implications for early theropod evolution. Zoological Journal of the Linnean Society 151: 377–421.
  • Suarez, C. A., T. K. Knobbe, J. L. Crowley, J. I. Kirkland, and A. R. C. Milner. 2017. A chronostratigraphic assessment of the Moenave Formation, USA using C-isotope chemostratigraphy and detrital zircon geochronology: Implications for the terrestrial end Triassic extinction. Earth and Planetary Science Letters 475: 83–93.
  • Sues, H.-D. 1986. The skull and dentition of two tritylodontid synapsids from the Lower Jurassic of western North America. Bulletin of the Museum of Comparative Zoology at Harvard College 151:217–268.
  • Sues, H.-D., S. J. Nesbitt, D. S. Berman, and A. C. Henrici. 2011. A late-surviving basal theropod dinosaur from the latest Triassic of North America. Proceedings of the Royal Society B Biological Sciences 278. doi: 10.1098/rspb.2011.0410.
  • Thulborn, R. A. 1970. The skull of Fabrosaurus australis, a Triassic ornithischian dinosaur. Palaeontology 13:414–432.
  • Thulborn, R. A. 1972. The postcranial skeleton of the Triassic ornithischian dinosaur Fabrosaurus australis. Palaeontology 15:29–60.
  • Tykoski, R. S. 1998. The osteology of Syntarsus kayentakatae and its implications for ceratosaurid phylogeny. M.Sc. thesis, The University of Texas at Austin, Austin, Texas, 217 pp.
  • Tykoski, R. S. 2005. Vertebrate paleontology in the Arizona Jurassic. Mesa Southwest Museum Bulletin 11:72–93.
  • Tykoski, R. S., and T. Rowe. 2004. Ceratosauria; pp. 47–70 in D. B. Weishampel, P. Dodson, and H. Osmólska (eds.), The Dinosauria, second edition. University of California Press, Berkeley, California.
  • Tykoski, R. S., T. B. Rowe, R. A. Ketcham, M. W. Colbert. 2002. Calsoyasuchus valliceps, a new crocodyliform from the Early Jurassic Kayenta Formation of Arizona. Journal of Vertebrate Paleontology 22:593–611.
  • United States Geological Survey. 1969a. Gold Spring Quadrangle. Arizona–Coconino County. 7.5 Minute Series (Topographic). United States Department of the Interior, Washington, D.C.
  • United States Geological Survey. 1969b. Rock Head Quadrangle. Arizona–Coconino County. 7.5 Minute Series (Topographic). United States Department of the Interior, Washington, D.C.
  • Wang, G.-F., H.-L. You, S.-G. Pan, and T. Wang. 2017. A new crested theropod dinosaur from the Early Jurassic of Yunnan Province, China. Vertebrata PalAsiatica 55:177–186.
  • Welles, S. P. 1954. New Jurassic dinosaur from the Kayenta Formation of Arizona. Bulletin of the Geological Society of America 65:591–598.
  • Welles, S. P. 1970. Dilophosaurus (Reptilia, Saurischia), a new name for a dinosaur. Journal of Paleontology 44:989.
  • Welles, S. P. 1984. Dilophosaurus wetherilli (Dinosauria, Theropoda) osteology and comparisons. Palaeontographica Abteilung A 185:85–180.
  • Wilson, J. A. 1999. A nomenclature for vertebral laminae in sauropods and other saurischian dinosaurs. Journal of Vertebrate Paleontology 19:639–953.
  • Yates, A. M. 2005. A new theropod dinosaur from the Early Jurassic of South Africa and its implications for the early evolution of theropods. Palaeontologia Africana 41:105–122.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.