This article was downloaded by: [Mount Allison University 0Libraries] On: 10 May 2013, At: 00:07 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Journal of Systematic Palaeontology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tjsp20 Skeletal morphology of Kritosaurus navajovius (Dinosauria: Hadrosauridae) from the Late Cretaceous of the North American south-west, with an evaluation of the phylogenetic systematics and biogeography of Kritosaurini Albert Prieto-Márquez a a Bayerische Staatssammlung für Paläontologie und Geologie , Richard-Wagner-Straße 10 , D-80333 Munich , Germany Published online: 08 May 2013. To cite this article: Albert Prieto-Márquez (2013): Skeletal morphology of Kritosaurus navajovius (Dinosauria: Hadrosauridae) from the Late Cretaceous of the North American south-west, with an evaluation of the phylogenetic systematics and biogeography of Kritosaurini, Journal of Systematic Palaeontology, DOI:10.1080/14772019.2013.770417 To link to this article: http://dx.doi.org/10.1080/14772019.2013.770417 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. 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Journal of Systematic Palaeontology, 2013 http://dx.doi.org/10.1080/14772019.2013.770417 Skeletal morphology of Kritosaurus navajovius (Dinosauria: Hadrosauridae) from the Late Cretaceous of the North American south-west, with an evaluation of the phylogenetic systematics and biogeography of Kritosaurini Albert Prieto-Marquez´ ∗ Bayerische Staatssammlung fur¨ Palaontologie¨ und Geologie, Richard-Wagner-Straße 10, D-80333 Munich, Germany (Received 26 March 2012; accepted 3 July 2012) The osteology of the hadrosaurid dinosaur Kritosaurus navajovius (late Campanian of southern North America) is documented in detail, and the taxonomy and phylogenetic relationships of the genus are revised. Kritosaurus is rediagnosed based on the extensive length of the dorsolateral margin of the maxilla and a unique combination of characters that includes a jugal with orbital constriction deeper than infratemporal one, infratemporal fenestra greater than orbit and with dorsal margin greatly elevated above dorsal orbital margin in adults, frontal participating in orbital margin, and paired caudal parasagittal processes of nasals resting over frontals. The taxonomy of numerous hadrosaurid specimens previously referred to Kritosaurus is reassessed; the vast majority of these cannot be positively referred to Kritosaurus. One exception is a specimen collected from the Cerro del Pueblo Formation that extends the geographical range of K. navajovius further south in Laramidia, to present-day northern Mexico. Anasazisaurus is regarded a junior synonym of Kritosaurus; their holotypes are indistinguishable from each other when considering the overlapping elements. However, many characters support distinction of Naashoibitosaurus ostromi as a valid taxon. Kritosaurus, consisting of the sister species K. navajovius and K. horneri, is deeply nested within Saurolophinae as a member of Kritosaurini. The latter clade includes also Naashoibitosaurus, Gryposaurus, and the South American Secernosaurus. Kritosaurini is characterized by a rostral nasal dorsal process not reaching the rostral margin of the narial foramen, frontal with triangular rostrolateral projection ending in a narrow apex (convergent in Brachylophosaurini), and a subrectangular dorsal region of infratemporal fenestra, among other characters. Kritosaurin hadrosaurids are hypothesized to have originated in southern Laramidia no later than the early Campanian. Subsequently, members of the clade reached northern Laramidia and South America via dispersal no later than the early and late Campanian, respectively. Keywords: Dinosauria; Hadrosauridae; Saurolophinae; phylogeny; biogeography; evolution Introduction ery and naming of Gryposaurus notabilis, a ‘hook-nosed’ hadrosaurid from the late Campanian Dinosaur Park Forma- Hadrosaurids are a Late Cretaceous radiation of large tion of southern Canada (Lambe 1914), Brown regarded (7–14 m long) ornithopod dinosaurs widespread in the Kritosaurus as congeneric with Gryposaurus. In a note Americas, Eurasia and Antarctica (Lull & Wright 1942; reproduced by Sinclair & Granger (1914, p. 303), Brown, Prieto-Marquez´ 2010a). These herbivores are remarkable in comparing the holotype skulls of K. navajovius (AMNH for their well-developed dental batteries, hypertrophied 5799) and G. notabilis (CMN 2278), stated: “In all Downloaded by [Mount Allison University 0Libraries] at 00:07 10 May 2013 nasal passages, and often, the possession of supracranial respects, including the remarkable development of the ornamentation (Hopson 1975). nasals, premaxillaries and predentary and reduction of One of the first hadrosaurid dinosaurs discovered, albeit the orbital portion of the frontal, this skull agrees with among the less understood, is Kritosaurus navajovius the type of Kritosaurus and there is no doubt of its generic Brown, 1910. The genus has one of the longer and more identity”. Consequently, Gryposaurus was widely accepted debated taxonomic histories in hadrosaurid systematics. as a junior synonym of Kritosaurus for many decades Brown (1910) originally erected the binomen K. navajovius (e.g. Gilmore 1916; Parks 1919, 1920; Lull & Wright on the basis of AMNH 5799, the partial skull of a 1942; Lapparent & Lavocat 1955; von Huene 1956; Young large hadrosaurid dinosaur (Figs 1–4). This specimen 1958; Langston 1960; Vialli 1960; Ostrom 1961; Waldman was collected in 1904 from late Campanian strata of 1969; Galton 1970; Hopson 1975; Taquet 1976; Baird & the upper Kirtland Formation near Ojo Alamo, San Juan Horner 1977, 1979; Horner 1979; Pinna 1979; Maryanska County, New Mexico (Brown 1910; Lull & Wright 1942; &Osmolska´ 1979; Davies 1983; Bonaparte et al. 1984; Williamson 2000) (Fig. 5). However, soon after the discov- Brett-Surman 1989; Weishampel & Horner 1990; Wagner ∗Email: [email protected] C 2013 Natural History Museum 2 A. Prieto-Marquez´ Downloaded by [Mount Allison University 0Libraries] at 00:07 10 May 2013 Figure 1. Partial holotype skull of Kritosaurus navajovius, AMNH 5799. A, left lateral view; B, interpretative drawing of the same; white areas indicate restored elements, which were reconstructed after acceptance of the synonymy of Kritosaurus with Gryposaurus and based on the latter (Lull & Wright 1942). Skeletal morphology of Kritosaurus navajovius 3 Downloaded by [Mount Allison University 0Libraries] at 00:07 10 May 2013 Figure 2. Partial holotype skull of Kritosaurus navajovius, AMNH 5799. A, right lateral view; photograph reproduced from Brown (1910, pl. 28), courtesy of the American Museum of Natural History; B, interpretative drawing of the same; white areas indicate reconstructed elements at the time of Brown’s (1910) original work on K. navajovius. 2001), despite a few dissenting voices (Lambe 1920; been refuted (Prieto-Marquez´ et al. 2006; Prieto-Marquez´ Morris 1973). Some authors went even further by consid- 2011). ering Kritosaurus a junior synonym of Hadrosaurus Leidy, In 1992, however, Horner resurrected Gryposaurus and 1858 (Baird & Horner 1977; Horner 1979; Brett-Surman revised the taxonomic status of Kritosaurus, pointing out 1979; Lehman 1981), although this synonymy has recently important differences in the morphology of the nasofrontal 4 A. Prieto-Marquez´ (holotype BYU 12950) and Naashoibitosaurus ostromi (holotype NMMNH P-16106). Additional hadrosaurid materials recovered within the USA in regions other than the type locality of Kritosaurus navajovius have been referred to the genus (see Online Supplementary Material Table 1). These include the Kimbe- toh Wash of the late Campanian Kirtland Formation (Gilmore 1919, 1935; Lehman 1981; Lucas et al. 1987; Brett-Surman 1989; Horner 1992; Williamson 2000), the late Campanian Fruitland Formation of New Mexico (Lucas et al. 1987; Wagner 2001), the late Campanian–early Maastrichtian Aguja (Davies 1983; Lehman 2001; Sankey 2001) and middle–late Maastrichtian Javelina (Wagner 2001) formations cropping out in Big Bend National Park, Texas and, tentatively, the marine Bearpaw Shale of south- central Montana (Horner 1992). Likewise, two hadrosaurid exemplars from the late Campanian Olmos and Cerro del Pueblo formations in the Sabinas and Parras basins, respectively, of Coahuila, northern Mexico, have also been referred to Kritosaurus (Hernandez´ et al. 2003; Serrano- Branas˜ 2006; Kirkland et al. 2006). Finally, Bonaparte et al. (1984) erected a new species of Kritosaurus, K. australis, based on partial cranial and postcranial remains from the