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Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger PAUL C. SERENO and STEPHEN L. BRUSATTE Sereno, P.C. and Brusatte, S.L. 2008. Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger. Acta Palaeontologica Polonica 53 (1): 15–46. We report the discovery of basal abelisaurid and carcharodontosaurid theropods from the mid Cretaceous (Aptian– Albian, ca. 112 Ma) Elrhaz Formation of the Niger Republic. The abelisaurid, Kryptops palaios gen. et sp. nov., is repre− sented by a single individual preserving the maxilla, pelvic girdle, vertebrae and ribs. Several features, including a maxilla textured externally by impressed vascular grooves and a narrow antorbital fossa, clearly place Kryptops palaios within Abelisauridae as its oldest known member. The carcharodontosaurid, Eocarcharia dinops gen. et sp. nov., is repre− sented by several cranial bones and isolated teeth. Phylogenetic analysis places it as a basal carcharodontosaurid, similar to Acrocanthosaurus and less derived than Carcharodontosaurus and Giganotosaurus. The discovery of these taxa sug− gests that large body size and many of the derived cranial features of abelisaurids and carcharodontosaurids had already evolved by the mid Cretaceous. The presence of a close relative of the North American genus Acrocanthosaurus on Af− rica suggests that carcharodontosaurids had already achieved a trans−Tethyan distribution by the mid Cretaceous. Key words: Theropod, abelisaurid, allosauroid, carcharodontosaurid, Kryptops, Eocarcharia, Cretaceous, Africa. Paul C. Sereno [[email protected]], Department of Organismal Biology and Anatomy, University of Chicago, 1027 E. 57th Street, Chicago, Illinois, 60637, USA; Stephen L. Brusatte [[email protected]], Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen’s Road, Bristol BS8 1RJ, United Kingdom. -
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. -
Tyrannosaurus
Natural Sciences 360 Legacy of Life Lecture 16 Dr. Stuart S. Sumida Theropoda (Including Birds) Recall: Crocodylomorpha Pterosauria Eoraptor Herrerasauridae Saurischia Ornithischia Dinosauria Archosauria THEROPODA •Pronograde bipeds. •Pneumatic (hollow) bones. •Enlarged hand. •Vestigial digits IV and V on hand. •Highly extendable digits I-III on hand. •Compact, elongate, narrow foot – usually missing digit V. Theropod Feet: Note missing V. I IV II III CERATOSAURIA: COELOPHYSOIDEA Difficult to diagnose, as they retain many primitive features: •Pronograde bipeds. •Relatively small. •Skulls are narrow, not boxy in shape. •Many undifferentiated teeth. Best known taxa: Coelophysis Dilolphosaurus “Syntarsus” Dilophosaurus: a crested ceratosaur (No, they didn’t spit.) Coelophysis, skull Coelophysis: reconstructed in northern New Mexico Sauropodomorpha THEROPODA Coelophysoidea Saurischia * Abelisauridae Theropoda Spinosauroidea Allosauroidea Tetanurae Compsognathidae Tyrannosauroidea Coelurosauria Ornithomimosauria Oviraptorisauria Maniraptora Dromaeosauridae Ceratosauria * Troodontidae Avialae CERATOSAURIA: ABELISAURIDAE •Bony outgrowths over the orbits. •Relatively short skull compared to Coelophysoidea. •Blunt snout. •Ornamentation on skull •Reduced forelimbs (like T. rex), but retain a well-developed pectoral girdle. Bony outgrowths over the orbits. Blunt snout. Relatively short skull compared to Coelophysoidea. Carnotaurus Majungatholus Sauropodomorpha THEROPODA Coelophysoidea Saurischia * Abelisauridae Theropoda Spinosauroidea Allosauroidea -
A New Theropod Dinosaur from the Early Jurassic of South Africa and Its Implications for the Early Evolution of Theropods
A new theropod dinosaur from the Early Jurassic of South Africa and its implications for the early evolution of theropods Adam M. Yates Bernard Price Institute for Palaeontological Research, School of Geosciences, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa E-mail: [email protected] Received 27 June 2005. Accepted 21 September 2005 A new theropod, Dracovenator regenti, from the upper Elliot Formation is described, based upon a fragmentary skull. It can be diagnosed on the basis of a bilobed fossa on the lateral surface of the premaxilla that is connected to the alveolar margin by a narrow channel, the presence of a deep, oblique, lateral notch on the articular and hypertrophied dorsal processes on the articular. Other aspects of its morphology display a mosaic of coelophysoid and advanced theropod characteristics. A cladistic analysis of basal Theropoda, including the new taxon finds that the new taxon is closely related to Dilophosaurus wetherilli and Zupaysaurus rougieri although the clade formed by these three taxa is not robustly supported. It also finds that Coelophysoidea sensu lato is paraphyletic with respect to Ceratosauria + Tetanurae but that this topology is not a significantly better explanation of the data than an inclusive, monophyletic Coelophysoidea. Keywords: Theropoda, Coelophysoidea, Dracovenator, upper Elliot Formation, South Africa. INTRODUCTION 2004). It is now the majority view amongst theropod Prior to Gauthier’s classic (1986) monograph, our under- systematists that Ceratosauria contains Ceratosaurus spp. standing of the interrelationships of theropod dinosaurs and Abelisauroidea and that this clade is more closely could be described as murky at best. -
A New Specimen of Acrocanthosaurus Atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA
A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA Philip J. CURRIE Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, Alberta T0J 0Y0 (Canada) [email protected] Kenneth CARPENTER Denver Museum of Natural History, Department of Earth Sciences, City Park, Denver, Colorado 80205 (USA) [email protected] Currie P. J. & Carpenter K. 2000. — A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA. Geodiversitas 22 (2) : 207-246. The data matrix is available at http://www.mnhn.fr/publication/matadd/g00n2a3.html ABSTRACT A new skeleton of Acrocanthosaurus atokensis is the most complete specimen collected and has the only known complete skull. Aspects of the new skeleton are described in detail, with special attention directed to the morphology of the skull and forelimb. Although unquestionably one of the largest theropods ever found, it is smaller than Carcharodontosaurus, Giganotosaurus and Tyrannosaurus. Comparison with other theropods suggests that Acrocanthosaurus bears a strong resemblance to these taxa because of charac- KEY WORDS ters that are size determinate, and the evidence suggests Acrocanthosaurus is Dinosaurs, more closely related to Allosauridae than to Carcharodontosauridae. Three theropods, Early Cretaceous, families (Allosauridae, Carcharodontosauridae, Sinraptoridae) are recognized USA. in the Allosauroidea. GEODIVERSITAS • 2000 • 22 (2) © Publications Scientifiques du Muséum national d’Histoire naturelle, Paris. www.mnhn.fr/publication/ 207 Currie P. J. & Carpenter K. RÉSUMÉ Un nouveau specimen d’Acrocanthosaurus atokensis (Theropoda, Dinosauria) du Crétacé inférieur de la Formation Antlers (Crétacé inférieur, Aptien) de l’Oklahoma, États-Unis. -
The Dentition of Megalosaurid Theropods
The dentition of megalosaurid theropods CHRISTOPHE HENDRICKX, OCTÁVIO MATEUS, and RICARDO ARAÚJO Hendrickx, C., Mateus, O., and Araújo, R. 2015. The dentition of megalosaurid theropods. Acta Palaeontologica Polo- nica 60 (3): 627–642. Theropod teeth are particularly abundant in the fossil record and frequently reported in the literature. Yet, the dentition of many theropods has not been described comprehensively, omitting details on the denticle shape, crown ornamentations and enamel texture. This paucity of information has been particularly striking in basal clades, thus making identification of isolated teeth difficult, and taxonomic assignments uncertain. We here provide a detailed description of the dentition of Megalosauridae, and a comparison to and distinction from superficially similar teeth of all major theropod clades. Megalosaurid dinosaurs are characterized by a mesial carina facing mesiolabially in mesial teeth, centrally positioned carinae on both mesial and lateral crowns, a mesial carina terminating above the cervix, and short to well-developed in- terdenticular sulci between distal denticles. A discriminant analysis performed on a dataset of numerical data collected on the teeth of 62 theropod taxa reveals that megalosaurid teeth are hardly distinguishable from other theropod clades with ziphodont dentition. This study highlights the importance of detailing anatomical descriptions and providing additional morphometric data on teeth with the purpose of helping to identify isolated theropod teeth in the future. Key words: Theropoda, Tetanurae, Megalosauridae, dentition, teeth, morphometry. Christophe Hendrickx [[email protected]] and Octávio Mateus [[email protected]], Universidade Nova de Lisboa, GeoBioTec (formerly CICEGe), Departamento de Ciências da Terra, Faculdade de Ciências e Tec- nologia, Quinta da Torre, 2829-516, Caparica, Portugal; Museu da Lourinhã, 9 Rua João Luis de Moura, 2530-158, Lourinhã, Portugal. -
New Information on the Cranial Anatomy of Acrocanthosaurus Atokensis and Its Implications for the Phylogeny of Allosauroidea (Dinosauria: Theropoda)
New Information on the Cranial Anatomy of Acrocanthosaurus atokensis and Its Implications for the Phylogeny of Allosauroidea (Dinosauria: Theropoda) Drew R. Eddy*¤, Julia A. Clarke¤ Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina, United States of America Abstract Background: Allosauroidea has a contentious taxonomic and systematic history. Within this group of theropod dinosaurs, considerable debate has surrounded the phylogenetic position of the large-bodied allosauroid Acrocanthosaurus atokensis from the Lower Cretaceous Antlers Formation of North America. Several prior analyses recover Acrocanthosaurus atokensis as sister taxon to the smaller-bodied Allosaurus fragilis known from North America and Europe, and others nest Acrocanthosaurus atokensis within Carcharodontosauridae, a large-bodied group of allosauroids that attained a cosmopolitan distribution during the Early Cretaceous. Methodology/Principal Findings: Re-evaluation of a well-preserved skull of Acrocanthosaurus atokensis (NCSM 14345) provides new information regarding the palatal complex and inner surfaces of the skull and mandible. Previously inaccessible internal views and articular surfaces of nearly every element of the skull are described. Twenty-four new morphological characters are identified as variable in Allosauroidea, combined with 153 previously published characters, and evaluated for eighteen terminal taxa. Systematic analysis of this dataset recovers a single most parsimonious topology placing Acrocanthosaurus atokensis as a member of Allosauroidea, in agreement with several recent analyses that nest the taxon well within Carcharodontosauridae. Conclusions/Significance: A revised diagnosis of Acrocanthosaurus atokensis finds that the species is distinguished by four primary characters, including: presence of a knob on the lateral surangular shelf; enlarged posterior surangular foramen; supraoccipital protruding as a double-boss posterior to the nuchal crest; and pneumatic recess within the medial surface of the quadrate. -
A New Large−Bodied Theropod Dinosaur from the Middle Jurassic of Warwickshire, United Kingdom
A new large−bodied theropod dinosaur from the Middle Jurassic of Warwickshire, United Kingdom ROGER B.J. BENSON and JONATHAN D. RADLEY Benson, R.B.J. and Radley, J.D. 2010. A new large−bodied theropod dinosaur from the Middle Jurassic of Warwickshire, United Kingdom. Acta Palaeontologica Polonica 55 (1): 35–42. Previously undocumented postcranial material from the Chipping Norton Limestone Formation (Middle Jurassic: Lower Bathonian) of Cross Hands Quarry, near Little Compton, Warwickshire represents a new large−bodied theropod dinosaur, distinct from the contemporaneous Megalosaurus bucklandii. Cruxicheiros newmanorum gen. et sp. nov. is diagnosed by a single autapomorphy, the presence of a proximomedially inclined ridge within the groove that marks the lateral extent of the posterior flange of the femoral caput (trochanteric fossa). C. newmanorum shows three tetanuran features: widely separated cervical zygapophyses, a swollen ridge on the lateral surface of the iliac blade and an anterior spur of the caudal neural spines. However, due to fragmentary preservation its affinities within Tetanurae remain uncertain: phylogenetic analysis places it as the most basal tetanuran, the most basal megalosauroid (= spinosauroid) or the most basal neotetanuran. Key words: Dinosauria, Theropoda, Tetanurae, Megalosaurus, Cruxicheiros, Bathonian, Chipping Norton Limestone Formation, England. Roger B.J. Benson [[email protected]], Department of Earth Science, University of Cambridge, Downing Street, Cam− bridge, UK, CB2 3EQ; Jonathan D. Radley [[email protected]], Warwickshire Museum, Market Place, Warwick, UK CV34 4SA; School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK B15 2TT. Received 8 July 2009, accepted 18 November 2009, available online 20 November 2009. -
Morphofunctional Analysis of the Quadrate of Spinosauridae
RESEARCH ARTICLE Morphofunctional Analysis of the Quadrate of Spinosauridae (Dinosauria: Theropoda) and the Presence of Spinosaurus and a Second Spinosaurine Taxon in the Cenomanian of North Africa. Christophe Hendrickx1,2¤*, Octávio Mateus1,2, Eric Buffetaut3 1 GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal, 2 Museu da Lourinhã, Lourinhã, Portugal, 3 CNRS (UMR 8538), Laboratoire de Géologie de l’École Normale Supérieure, PSL Research University, Paris, France ¤ Current address: Evolutionary Studies Institute, Center of Excellence in Palaeosciences, University of the Witwatersrand, Johannesburg, South Africa * [email protected] OPEN ACCESS Citation: Hendrickx C, Mateus O, Buffetaut E (2016) Abstract Morphofunctional Analysis of the Quadrate of Spinosauridae (Dinosauria: Theropoda) and the Presence of Spinosaurus and a Second Spinosaurine Six quadrate bones, of which two almost certainly come from the Kem Kem beds (Cenoma- Taxon in the Cenomanian of North Africa. PLoS ONE nian, Upper Cretaceous) of south-eastern Morocco, are determined to be from juvenile and 11(1): e0144695. doi:10.1371/journal.pone.0144695 adult individuals of Spinosaurinae based on phylogenetic, geometric morphometric, and Editor: Alistair Robert Evans, Monash University, phylogenetic morphometric analyses. Their morphology indicates two morphotypes AUSTRALIA evidencing the presence of two spinosaurine taxa ascribed to Spinosaurus aegyptiacus Received: October 2, 2014 and? Sigilmassasaurus brevicollis in the Cenomanian of North Africa, casting doubt on the Accepted: November 20, 2015 accuracy of some recent skeletal reconstructions which may be based on elements from several distinct species. Morphofunctional analysis of the mandibular articulation of the Published: January 6, 2016 quadrate has shown that the jaw mechanics was peculiar in Spinosauridae. -
1 Lecture 6: Saurischia and Theropoda Saurischia Term Coined
Lecture 6: Saurischia and Theropoda Saurischia Term coined by Seeley (an employee of the Cambridge Museum) in 1887 Name is based on the anteriorlly-oriented pubis of most (but not all saurischians). This is not a shared derived trait; it is a primitive trait from deep in Reptilia Shared derived characters of Saurischia: Twisted thumb (digit 1) Reduced pinky (digit 5) New articulation points in dorsal vertebrae (hyposphene-hypantrum articulation) Elongation of forward neck (cervical) vertebrae Controversy over placement of earliest, carnivorous dinosaurs (Eoraptor, Herrerasaurus, etc.). 1) Basal Dinosaur 2) Basal Theropod (this is what I told you in class) 3) Basal Saurischian OUTLINE OF THEROPOD LECTURE 1. Defining characteristics of clades 2. Distribution in time and place 3. Lifestyle issues Theropods 1. Defining characteristics of clades Theropoda (‘beast foot’, really bird-footed) General characters: bipedal, carnivores (more or less), less abundant than herbivorous dinosaurs (only ½ to 1/11 as numerous), less diverse than herbivores (only 40%), classification nightmares, ranged in size from <2 feet/10 lbs. to 50 feet or more and 5-7 tons. Shared derived characters: big eyes, extra antorbital fenestra, broad lachrymal (“tear-duct”) bone, 3 elongate fingers (vestigal 4th and 5th digits) with grasping capability, narrow hind foot with three functional digits, hollow bones, bowed femur, sacrum with at least 5 vertebrae, pubic “boot”, tails stiff distally used as counterbalances, loosely-jointed kinetic skulls Long bones are hollow - have an outer layer of dense, compact bone that is far thicker than that of other dinosaurs; spongy bone confined to the articulation zones and edge of the marrow cavity. -
A New Phylogeny of the Carnivorous Dinosaurs
GAIA Nº 15, LISBOA/LISBON, DEZEMBRO/DECEMBER 1998, pp. 5-61 (ISSN: 0871-5424) A NEW PHYLOGENY OF THE CARNIVOROUS DINOSAURS Thomas R. HOLTZ, Jr. Department of Geology, University of Maryland. College Park, MARYLAND 20735. USA E-Mail: [email protected] ABSTRACT: The last several years have seen the discovery of many new theropod dinosaur taxa. Data obtained from these and from fragmentary forms not previously utilized in cladis- tic analyses are examined. An analysis of forty one primary ingroup taxa and 386 characters yielded a set of most parsimonious cladograms which preserves many previously discov- ered relationships (e.g., a basal split between Ceratosauria and Tetanurae; a carnosaur- coelurosaur clade Avetheropoda outside of more primitive "megalosaur" - grade teta- nurines; Dromaeosauridae as the sister taxon to birds, and so forth). The Middle Jurassic English Proceratosaurus was discovered to be a basal coelurosaur, as was (on less secure evidence) the Middle Jurassic Chinese Gasosaurus: these are among the oldest coeluro- saurs yet described. Several characters previously considered to be restricted to birds and other advanced coelurosaurs (e.g., furcula, semilunate carpal block) were found to be more broadly distributed among tetanurines. Other characters, once considered synapomor- phies for Avetheropoda (e.g., loss of metacarpal IV, possession of a pubic obturator notch) were found to be convergent between advanced carnosaurs and advanced coelurosaurs, lacking in the basal members of both clades. At least three (and possibly four) separate ori- gins for the arctometatarsalian pes were supported in this study. The mosaic of derived character state distributions for troodontids relative to the dromaeosaurid-bird clade, the tyrannosaurid-ornithomimosaur clade, and the therizinosauroid-oviraptorosaur clade sug- gests that relationships alternative to the most parsimonious found here may be supported in future studies. -
Neovenatorid Theropods Are Apex Predators in the Late Cretaceous of North America
ARTICLE Received 20 Jul 2013 | Accepted 25 Oct 2013 | Published 22 Nov 2013 DOI: 10.1038/ncomms3827 Neovenatorid theropods are apex predators in the Late Cretaceous of North America Lindsay E. Zanno1,2,3 & Peter J. Makovicky3 Allosauroid theropods were a diverse and widespread radiation of Jurassic–Cretaceous megapredators. Achieving some of the largest body sizes among theropod dinosaurs, these colossal hunters dominated terrestrial ecosystems until a faunal turnover redefined apex predator guild occupancy during the final 20 million years of the Cretaceous. Here we describe a giant new species of allosauroid – Siats meekerorum gen. et sp. nov. – providing the first evidence for the cosmopolitan clade Neovenatoridae in North America. Siats is the youngest allosauroid yet discovered from the continent and demonstrates that the clade endured there into the Late Cretaceous. The discovery provides new evidence for ecologic sympatry of large allosauroids and small-bodied tyrannosauroids. These data support the hypothesis that extinction of Allosauroidea in terrestrial ecosystems of North America permitted ecological release of tyrannosauroids, which went on to dominate end-Cretaceous food webs. 1 Paleontology and Geology Research Laboratory, North Carolina Museum of Natural Sciences, Raleigh, North Carolina 27601, USA. 2 Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27607, USA. 3 Department of Geology, Field Museum of Natural History, Chicago, Illinois 60640, USA. Correspondence and requests for materials