A New Possible Megalosauroid Theropod from the Middle Jurassic
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A Comprehensive Anatomical And
Journal of Paleontology, Volume 94, Memoir 78, 2020, p. 1–103 Copyright © 2020, The Paleontological Society. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/ licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. 0022-3360/20/1937-2337 doi: 10.1017/jpa.2020.14 A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona Adam D. Marsh1,2 and Timothy B. Rowe1 1Jackson School of Geosciences, the University of Texas at Austin, 2305 Speedway Stop C1160, Austin, Texas 78712, USA <[email protected]><[email protected]> 2Division of Resource Management, Petrified Forest National Park, 1 Park Road #2217, Petrified Forest, Arizona 86028, USA Abstract.—Dilophosaurus wetherilli was the largest animal known to have lived on land in North America during the Early Jurassic. Despite its charismatic presence in pop culture and dinosaurian phylogenetic analyses, major aspects of the skeletal anatomy, taxonomy, ontogeny, and evolutionary relationships of this dinosaur remain unknown. Skeletons of this species were collected from the middle and lower part of the Kayenta Formation in the Navajo Nation in northern Arizona. Redescription of the holotype, referred, and previously undescribed specimens of Dilophosaurus wetherilli supports the existence of a single species of crested, large-bodied theropod in the Kayenta Formation. The parasagittal nasolacrimal crests are uniquely constructed by a small ridge on the nasal process of the premaxilla, dorsoventrally expanded nasal, and tall lacrimal that includes a posterior process behind the eye. -
Implications for Predatory Dinosaur Macroecology and Ontogeny in Later Late Cretaceous Asiamerica
Canadian Journal of Earth Sciences Theropod Guild Structure and the Tyrannosaurid Niche Assimilation Hypothesis: Implications for Predatory Dinosaur Macroecology and Ontogeny in later Late Cretaceous Asiamerica Journal: Canadian Journal of Earth Sciences Manuscript ID cjes-2020-0174.R1 Manuscript Type: Article Date Submitted by the 04-Jan-2021 Author: Complete List of Authors: Holtz, Thomas; University of Maryland at College Park, Department of Geology; NationalDraft Museum of Natural History, Department of Geology Keyword: Dinosaur, Ontogeny, Theropod, Paleocology, Mesozoic, Tyrannosauridae Is the invited manuscript for consideration in a Special Tribute to Dale Russell Issue? : © The Author(s) or their Institution(s) Page 1 of 91 Canadian Journal of Earth Sciences 1 Theropod Guild Structure and the Tyrannosaurid Niche Assimilation Hypothesis: 2 Implications for Predatory Dinosaur Macroecology and Ontogeny in later Late Cretaceous 3 Asiamerica 4 5 6 Thomas R. Holtz, Jr. 7 8 Department of Geology, University of Maryland, College Park, MD 20742 USA 9 Department of Paleobiology, National Museum of Natural History, Washington, DC 20013 USA 10 Email address: [email protected] 11 ORCID: 0000-0002-2906-4900 Draft 12 13 Thomas R. Holtz, Jr. 14 Department of Geology 15 8000 Regents Drive 16 University of Maryland 17 College Park, MD 20742 18 USA 19 Phone: 1-301-405-4084 20 Fax: 1-301-314-9661 21 Email address: [email protected] 22 23 1 © The Author(s) or their Institution(s) Canadian Journal of Earth Sciences Page 2 of 91 24 ABSTRACT 25 Well-sampled dinosaur communities from the Jurassic through the early Late Cretaceous show 26 greater taxonomic diversity among larger (>50kg) theropod taxa than communities of the 27 Campano-Maastrichtian, particularly to those of eastern/central Asia and Laramidia. -
Prootic Anatomy of a Juvenile Tyrannosauroid from New Jersey and Its Implications for the Morphology and Evolution of the Tyrannosauroid Braincase
Prootic anatomy of a juvenile tyrannosauroid from New Jersey and its implications for the morphology and evolution of the tyrannosauroid braincase Chase D Brownstein Corresp. 1 1 Collections and Exhibitions, Stamford Museum & Nature Center, Stamford, Connecticut, United States Corresponding Author: Chase D Brownstein Email address: [email protected] Among the most recognizable theropods are the tyrannosauroids, a group of small to large carnivorous coelurosaurian dinosaurs that inhabited the majority of the northern hemisphere during the Cretaceous and came to dominate large predator niches in North American and Asian ecosystems by the end of the Mesozoic era. The clade is among the best-represented of dinosaur groups in the notoriously sparse fossil record of Appalachia, the Late Cretaceous landmass that occupied the eastern portion of North America after its formation from the transgression of the Western Interior Seaway. Here, the prootic of a juvenile tyrannosauroid collected from the middle-late Campanian Marshalltown Formation of the Atlantic Coastal Plain is described, remarkable for being the first concrete evidence of juvenile theropods in that plain during the time of the existence of Appalachia and the only portion of theropod braincase known from the landmass. Phylogenetic analysis recovers the specimen as an “intermediate” tyrannosauroid of similar grade to Dryptosaurus and Appalachiosaurus. Comparisons with the corresponding portions of other tyrannosauroid braincases suggest that the Ellisdale prootic is more similar to Turonian forms in morphology than to the derived tyrannosaurids of the Late Cretaceous, thus supporting the hypothesis that Appalachian tyrannosauroids and other vertebrates were relict forms surviving in isolation from their derived counterparts in Eurasia. -
The Nonavian Theropod Quadrate II: Systematic Usefulness, Major Trends and Cladistic and Phylogenetic Morphometrics Analyses
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/272162807 The nonavian theropod quadrate II: systematic usefulness, major trends and cladistic and phylogenetic morphometrics analyses Article · January 2014 DOI: 10.7287/peerj.preprints.380v2 CITATION READS 1 90 3 authors: Christophe Hendrickx Ricardo Araujo University of the Witwatersrand Technical University of Lisbon 37 PUBLICATIONS 210 CITATIONS 89 PUBLICATIONS 324 CITATIONS SEE PROFILE SEE PROFILE Octávio Mateus University NOVA of Lisbon 224 PUBLICATIONS 2,205 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Nature and Time on Earth - Project for a course and a book for virtual visits to past environments in learning programmes for university students (coordinators Edoardo Martinetto, Emanuel Tschopp, Robert A. Gastaldo) View project Ten Sleep Wyoming Jurassic dinosaurs View project All content following this page was uploaded by Octávio Mateus on 12 February 2015. The user has requested enhancement of the downloaded file. The nonavian theropod quadrate II: systematic usefulness, major trends and cladistic and phylogenetic morphometrics analyses Christophe Hendrickx1,2 1Universidade Nova de Lisboa, CICEGe, Departamento de Ciências da Terra, Faculdade de Ciências e Tecnologia, Quinta da Torre, 2829-516, Caparica, Portugal. 2 Museu da Lourinhã, 9 Rua João Luis de Moura, 2530-158, Lourinhã, Portugal. s t [email protected] n i r P e 2,3,4,5 r Ricardo Araújo P 2 Museu da Lourinhã, 9 Rua João Luis de Moura, 2530-158, Lourinhã, Portugal. 3 Huffington Department of Earth Sciences, Southern Methodist University, PO Box 750395, 75275-0395, Dallas, Texas, USA. -
Cranial Anatomy of Allosaurus Jimmadseni, a New Species from the Lower Part of the Morrison Formation (Upper Jurassic) of Western North America
Cranial anatomy of Allosaurus jimmadseni, a new species from the lower part of the Morrison Formation (Upper Jurassic) of Western North America Daniel J. Chure1,2,* and Mark A. Loewen3,4,* 1 Dinosaur National Monument (retired), Jensen, UT, USA 2 Independent Researcher, Jensen, UT, USA 3 Natural History Museum of Utah, University of Utah, Salt Lake City, UT, USA 4 Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, USA * These authors contributed equally to this work. ABSTRACT Allosaurus is one of the best known theropod dinosaurs from the Jurassic and a crucial taxon in phylogenetic analyses. On the basis of an in-depth, firsthand study of the bulk of Allosaurus specimens housed in North American institutions, we describe here a new theropod dinosaur from the Upper Jurassic Morrison Formation of Western North America, Allosaurus jimmadseni sp. nov., based upon a remarkably complete articulated skeleton and skull and a second specimen with an articulated skull and associated skeleton. The present study also assigns several other specimens to this new species, Allosaurus jimmadseni, which is characterized by a number of autapomorphies present on the dermal skull roof and additional characters present in the postcrania. In particular, whereas the ventral margin of the jugal of Allosaurus fragilis has pronounced sigmoidal convexity, the ventral margin is virtually straight in Allosaurus jimmadseni. The paired nasals of Allosaurus jimmadseni possess bilateral, blade-like crests along the lateral margin, forming a pronounced nasolacrimal crest that is absent in Allosaurus fragilis. Submitted 20 July 2018 Accepted 31 August 2019 Subjects Paleontology, Taxonomy Published 24 January 2020 Keywords Allosaurus, Allosaurus jimmadseni, Dinosaur, Theropod, Morrison Formation, Jurassic, Corresponding author Cranial anatomy Mark A. -
The Postcranial Skeleton of Monolophosaurus Jiangi
Geol. Mag. 147 (1), 2010, pp. 13–27. c Cambridge University Press 2009 13 doi:10.1017/S0016756809990240 The postcranial skeleton of Monolophosaurus jiangi (Dinosauria: Theropoda) from the Middle Jurassic of Xinjiang, China, and a review of Middle Jurassic Chinese theropods ∗ ZHAO XI-JIN , ROGER B. J. BENSON†‡, STEPHEN L. BRUSATTE§ & PHILIP J. CURRIE¶ ∗ Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, P.O. Box 643, Beijing 100044, People’s Republic of China †Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK ‡Natural History Museum, Cromwell Road, London SW7 5BD, UK §Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK ¶University of Alberta, Biological Sciences CW405, Edmonton, Alberta T6G 2N9, Canada (Received 10 December 2008; accepted 27 April 2009; First published online 9 July 2009) Abstract – The Middle Jurassic was a critical time in the evolution of theropod dinosaurs, highlighted by the origination and radiation of the large-bodied and morphologically diverse Tetanurae. Middle Jurassic tetanurans are rare but have been described from Europe, South America and China. In particular, China has yielded a number of potential basal tetanurans, but these have received little detailed treatment in the literature. Here we redescribe the postcranial skeleton of one of the most complete Chinese Middle Jurassic theropods, Monolophosaurus. Several features confirm the tetanuran affinities of Monolophosaurus, but the possession of ‘primitive’ traits such as a double-faceted pubic peduncle of the ilium and a hood-like supracetabular crest suggest a basal position within Tetanurae. This conflicts with most published cladistic analyses that place Monolophosaurus in a more derived position within Allosauroidea. -
A Century of Spinosaurs - a Review and Revision of the Spinosauridae
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Queen Mary Research Online A century of spinosaurs - a review and revision of the Spinosauridae with comments on their ecology HONE David William Elliott1, * HOLTZ Thomas Richard Jnr2 1 School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK 2 Department of Geology, University of Maryland, College Park, MD 20742 USA Abstract: The spinosaurids represent an enigmatic and highly unusual form of large tetanuran theropods that were first identified in 1915. A recent flurry of discoveries and taxonomic revisions of this important and interesting clade had added greatly to our knowledge, however, spinosaur body fossils are generally rare and most species are known from only limited skeletal remains. Their unusual anatomical adaptations to the skull, limbs and axial column all differ from other large theropods and point to an unusual ecological niche and a lifestyle intimately linked to water. Keywords: Theropoda, Megalosauroidea, Baryonychinae, Spinosaurinae, palaeoecology E-mail: [email protected] 1 Introduction The Spinosauridae is an enigmatic clade of large and carnivorous theropods from the Jurassic and Cretaceous that are known from both Gondwana and Laurasia (Holtz et al., 2004). Despite their wide temporal and geographic distribution, the clade is known primarily from teeth and the body fossil record is extremely limited (Bertin, 2010). As such, relatively little is known about this group of animals, although their unusual morphology with regard to skull shape, dentition, dorsal neural spines and other features mark them out as divergent from the essential bauplan of other non-tetanuran theropods (Fig 1). -
Birds Have Paedomorphic Dinosaur Skulls
LETTER doi:10.1038/nature11146 Birds have paedomorphic dinosaur skulls Bhart-Anjan S. Bhullar1, Jesu´s Maruga´n-Lobo´n2, Fernando Racimo1, Gabe S. Bever3, Timothy B. Rowe4, Mark A. Norell5 & Arhat Abzhanov1 The interplay of evolution and development has been at the heart of which includes Archaeopteryx and modern birds, seem to change little evolutionary theory for more than a century1. Heterochrony— from juvenile to adult. The Eichsta¨tt and Berlin specimens of change in the timing or rate of developmental events—has been Archaeopteryx (Fig. 1d) are nearly identical cranially despite the fact implicated in the evolution of major vertebrate lineages such as a mammals2, including humans1. Birds are the most speciose land Euparkeria vertebrates, with more than 10,000 living species3 representing a Alligator bewildering array of ecologies. Their anatomy is radically different Herrerasaurus from that of other vertebrates. The unique bird skull houses two Eoraptor highly specialized systems: the sophisticated visual and neuro- Theropoda Coelophysis 4,5 muscular coordination system allows flight coordination and Dilophosaurus exploitation of diverse visual landscapes, and the astonishing Ceratosauria variations of the beak enable a wide range of avian lifestyles. Megalosauroidea Here we use a geometric morphometric approach integrating developmental, neontological and palaeontological data to show Carnosauria that the heterochronic process of paedomorphosis, by which Compsognathidae descendants resemble the juveniles of their ancestors, is respons- Tyrannosauroidea Coelurosauria ible for several major evolutionary transitions in the origin of Ornithomimosauria birds. We analysed the variability of a series of landmarks on all Alvarezsauroidea known theropod dinosaur skull ontogenies as well as outgroups Therizinosauroidea + and birds. -
Mapusaurus Roseae N
A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina Rodolfo A. CORIA CONICET, Museo Carmen Funes, Av. Córdoba 55, 8318 Plaza Huincul, Neuquén (Argentina) [email protected] Philip J. CURRIE University of Alberta, Department of Biological Sciences, Edmonton, Alberta T6G 2E9 (Canada) [email protected] Coria R. A. & Currie P. J. 2006. — A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina. Geodiversitas 28 (1) : 71-118. ABSTRACT A new carcharodontosaurid theropod from the Huincul Formation (Aptian- Cenomanian, Upper Cretaceous) of Neuquén Province, Argentina, is described. Approximately the same size as Giganotosaurus carolinii Coria & Salgado, 1995, Mapusaurus roseae n. gen., n. sp. is characterized by many features including a deep, short and narrow skull with relatively large triangular antorbital fossae, relatively small maxillary fenestra, and narrow, unfused rugose nasals. Mapu- saurus roseae n. gen., n. sp. has cervical neural spines and distally tapering epipo- physes, tall dorsal neural spines, central pleurocoels as far back as the first sacral vertebra, accessory caudal neural spines, stout humerus with poorly defined distal condyles, fused metacarpals, ilium with brevis fossa extending deeply into ischial peduncle, and femur with low fourth trochanter. Phylogenetic analysis indicates that Mapusaurus n. gen. shares with Carcharodontosaurus Stromer, 1931 and Giganotosaurus Coria & Salgado, 1995 several derived features that include narrow blade-like teeth with wrinkled enamel, heavily sculptured fa- cial bones, supraorbital shelf formed by a postorbital/palpebral complex, and a dorsomedially directed femoral head. Remains of Mapusaurus n. gen. were recovered from a bonebed where 100% of the identifiable dinosaur bones can KEY WORDS be assigned to this new genus. -
A New Clade of Archaic Large-Bodied Predatory Dinosaurs (Theropoda: Allosauroidea) That Survived to the Latest Mesozoic
Naturwissenschaften (2010) 97:71–78 DOI 10.1007/s00114-009-0614-x ORIGINAL PAPER A new clade of archaic large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic Roger B. J. Benson & Matthew T. Carrano & Stephen L. Brusatte Received: 26 August 2009 /Revised: 27 September 2009 /Accepted: 29 September 2009 /Published online: 14 October 2009 # Springer-Verlag 2009 Abstract Non-avian theropod dinosaurs attained large Neovenatoridae includes a derived group (Megaraptora, body sizes, monopolising terrestrial apex predator niches new clade) that developed long, raptorial forelimbs, in the Jurassic–Cretaceous. From the Middle Jurassic cursorial hind limbs, appendicular pneumaticity and small onwards, Allosauroidea and Megalosauroidea comprised size, features acquired convergently in bird-line theropods. almost all large-bodied predators for 85 million years. Neovenatorids thus occupied a 14-fold adult size range Despite their enormous success, however, they are usually from 175 kg (Fukuiraptor) to approximately 2,500 kg considered absent from terminal Cretaceous ecosystems, (Chilantaisaurus). Recognition of this major allosauroid replaced by tyrannosaurids and abelisaurids. We demon- radiation has implications for Gondwanan paleobiogeog- strate that the problematic allosauroids Aerosteon, Austral- raphy: The distribution of early Cretaceous allosauroids ovenator, Fukuiraptor and Neovenator form a previously does not strongly support the vicariant hypothesis of unrecognised but ecologically diverse and globally distrib- southern dinosaur evolution or any particular continental uted clade (Neovenatoridae, new clade) with the hitherto breakup sequence or dispersal scenario. Instead, clades enigmatic theropods Chilantaisaurus, Megaraptor and the were nearly cosmopolitan in their early history, and later Maastrichtian Orkoraptor. This refutes the notion that distributions are explained by sampling failure or local allosauroid extinction pre-dated the end of the Mesozoic. -
The Origin and Evolution of the Dinosaur Infraorder Carnosauria*
PALEONTOLOGICHESKIY ZHURNAL 1989 No. 4 KURZANOV S. M. THE ORIGIN AND EVOLUTION OF THE DINOSAUR INFRAORDER CARNOSAURIA* Paleontological Institute of the Academy of Sciences of the USSR Based on a revision of the systematic composition of the carnosaur families, a new diagram of the phylogenetic relationships within the infraorder is proposed. The question of carnosaurs cannot be considered to be resolved. Excluding the Triassic forms, carnosaurs in the broad or narrow sense have always been considered to be a group of theropods because they are only slightly different from them in fundamental features associated with large body size and a predatory lifestyle. The Late Triassic genera, such as Teratosaurus and Sinosaurus [33], were assigned to these on the basis of extremely meager material and without sufficient justification. This assignment has subsequently been rejected by most authors [13, 16, 17, 24, 25]. Huene [23] suggested that, along with the Sauropoda and Prosauropoda, the carnosaurs form a natural group Pachypodosauria, within which they are thought to be direct descendants of the prosauropods (the carnosaurs proceed directly from Teratosaurus through Magnosaurus). Studies of abundant cranial material (which actually belongs to Sellosaurus gracilis Huene) gave reason to think that the first species had been a prosauropod, whereas typical material (maxilla, ischium) belong to thecodonts from the family Poposauridae [24]. Huene’s diagram, which initially did not receive support, was widely propagated by the discovery of an unusual carnosaur Torvosaurus tanneri Galton et Jensen in the Upper Triassic deposits of Colorado [25]. The exceptionally plesiomorphic nature of some of its features, in the authors’ opinion, gave sufficient justification for removing them from the prosauropods. -
Theropod Dinosaurs from Argentina
139 Theropod dinosaurs from Argentina Martín D. EZCURRA1 & Fernando E. NOVAS2 1CONICET, Sección Paleontología Vertebrados, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Av. Angel Gallardo 470, Buenos Aires, C1405DJR, Argentina. [email protected], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Av. Ángel Gallardo 470, Buenos Aires, C1405DJR, Argentina. [email protected] Abstract. Theropoda includes all the dinosaurs more closely related to birds than to sauropodomorphs (long-necked dinosaurs) and ornithischians (bird-hipped dinosaurs). The oldest members of the group are early Late Triassic in age, and non-avian theropods flourished during the rest of the Mesozoic until they vanished in the Cretaceous-Palaeogene mass extinction. Theropods radiated into two main lineages, Ceratosauria and Tetanurae, which are well represented in Cretaceous rocks from Argentina. Ceratosaurians are the most taxonomically diverse South American non-avian theropods, including small to large-sized species, such as the iconic horned dinosaur Carnotaurus. Argentinean tetanurans are represented by multiple lineages that include some of the largest carnivorous dinosaurs known worldwide (carcharodontosaurids), the enigmatic large-clawed megaraptorans, and small to medium-sized species very closely related to avialans (e.g. unenlagiids). The Argentinean non-avian theropod record has been and is crucial to understand the evolutionary and palaeobiogeographical