Estimating the Evolutionary Rates in Mosasauroids and Plesiosaurs: Discussion of Niche Occupation in Late Cretaceous Seas
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JVP 26(3) September 2006—ABSTRACTS
Neoceti Symposium, Saturday 8:45 acid-prepared osteolepiforms Medoevia and Gogonasus has offered strong support for BODY SIZE AND CRYPTIC TROPHIC SEPARATION OF GENERALIZED Jarvik’s interpretation, but Eusthenopteron itself has not been reexamined in detail. PIERCE-FEEDING CETACEANS: THE ROLE OF FEEDING DIVERSITY DUR- Uncertainty has persisted about the relationship between the large endoskeletal “fenestra ING THE RISE OF THE NEOCETI endochoanalis” and the apparently much smaller choana, and about the occlusion of upper ADAM, Peter, Univ. of California, Los Angeles, Los Angeles, CA; JETT, Kristin, Univ. of and lower jaw fangs relative to the choana. California, Davis, Davis, CA; OLSON, Joshua, Univ. of California, Los Angeles, Los A CT scan investigation of a large skull of Eusthenopteron, carried out in collaboration Angeles, CA with University of Texas and Parc de Miguasha, offers an opportunity to image and digital- Marine mammals with homodont dentition and relatively little specialization of the feeding ly “dissect” a complete three-dimensional snout region. We find that a choana is indeed apparatus are often categorized as generalist eaters of squid and fish. However, analyses of present, somewhat narrower but otherwise similar to that described by Jarvik. It does not many modern ecosystems reveal the importance of body size in determining trophic parti- receive the anterior coronoid fang, which bites mesial to the edge of the dermopalatine and tioning and diversity among predators. We established relationships between body sizes of is received by a pit in that bone. The fenestra endochoanalis is partly floored by the vomer extant cetaceans and their prey in order to infer prey size and potential trophic separation of and the dermopalatine, restricting the choana to the lateral part of the fenestra. -
Cryptoclidid Plesiosaurs (Sauropterygia, Plesiosauria) from the Upper Jurassic of the Atacama Desert
Journal of Vertebrate Paleontology ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/ujvp20 Cryptoclidid plesiosaurs (Sauropterygia, Plesiosauria) from the Upper Jurassic of the Atacama Desert Rodrigo A. Otero , Jhonatan Alarcón-Muñoz , Sergio Soto-Acuña , Jennyfer Rojas , Osvaldo Rojas & Héctor Ortíz To cite this article: Rodrigo A. Otero , Jhonatan Alarcón-Muñoz , Sergio Soto-Acuña , Jennyfer Rojas , Osvaldo Rojas & Héctor Ortíz (2020): Cryptoclidid plesiosaurs (Sauropterygia, Plesiosauria) from the Upper Jurassic of the Atacama Desert, Journal of Vertebrate Paleontology, DOI: 10.1080/02724634.2020.1764573 To link to this article: https://doi.org/10.1080/02724634.2020.1764573 View supplementary material Published online: 17 Jul 2020. Submit your article to this journal Article views: 153 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ujvp20 Journal of Vertebrate Paleontology e1764573 (14 pages) © by the Society of Vertebrate Paleontology DOI: 10.1080/02724634.2020.1764573 ARTICLE CRYPTOCLIDID PLESIOSAURS (SAUROPTERYGIA, PLESIOSAURIA) FROM THE UPPER JURASSIC OF THE ATACAMA DESERT RODRIGO A. OTERO,*,1,2,3 JHONATAN ALARCÓN-MUÑOZ,1 SERGIO SOTO-ACUÑA,1 JENNYFER ROJAS,3 OSVALDO ROJAS,3 and HÉCTOR ORTÍZ4 1Red Paleontológica Universidad de Chile, Laboratorio de Ontogenia y Filogenia, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Santiago, Chile, [email protected]; 2Consultora Paleosuchus Ltda., Huelén 165, Oficina C, Providencia, Santiago, Chile; 3Museo de Historia Natural y Cultural del Desierto de Atacama. Interior Parque El Loa s/n, Calama, Región de Antofagasta, Chile; 4Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Barrio Universitario, Concepción, Región del Bío Bío, Chile ABSTRACT—This study presents the first plesiosaurs recovered from the Jurassic of the Atacama Desert that are informative at the genus level. -
Tylosaurine Mosasaurs (Squamata) from the Late Cretaceous of Northern Germany
Netherlands Journal of Geosciences —– Geologie en Mijnbouw | 94 – 1 | 55-71 | 2015 doi: 10.1017/njg.2014.31 Tylosaurine mosasaurs (Squamata) from the Late Cretaceous of northern Germany J.J. Hornung1,2,* &M.Reich3,4 1 Georg-August University Gottingen,¨ Geoscience Centre, Department of Geobiology, Goldschmidt-Straße 3, 37077 Gottingen,¨ Germany 2 Current address: Fuhlsbuttler¨ Str. 611, 22337 Hamburg, Germany 3 SNSB - Bavarian State Collection for Palaeontology and Geology, Richard-Wagner-Str. 10, 80333 Munich, Germany 4 Department of Earth and Environmental Sciences, Ludwig-Maximilians University Munchen,¨ Richard-Wagner-Str. 10, 80333 Munich, Germany * Corresponding author. Email: [email protected] Manuscript received: 27 April 2014, accepted: 18 September 2014 Abstract Two genera of tylosaurine mosasaurs, Tylosaurus and Hainosaurus, are recorded for the first time from Germany. Tylosaurus sp. is represented by two isolated tooth crowns, originally described as Mosasaurus? alseni (here considered a nomen dubium) from the latest Santonian–Early Campanian, which are very similar to T. ivoensis and T. gaudryi.ThematerialofHainosaurus sp. comprises a maxillary with associated postorbitofrontal, two pterygoid teeth and several indeterminate cranial fragments. The specimen from the Late Campanian is slightly less derived than H. bernardi from the Maastrichtian in retaining labiolingually less compressed anterior maxillary teeth and unserrated pterygoid teeth with only very weak carinae. Despite only minor skeletal differences, the genus Hainosaurus is considered to be distinct from Tylosaurus because of its significant modification of the dental apparatus compared to the plesiomorphic condition in the latter. This dental morphology suggests a phylogenetic trend from a generalised-piercing marginal dentition in Tylosaurus towards the increasingly labiolingually compressed, symmetrical, strongly bicarinate cutting marginal teeth in Hainosaurus spp. -
Evaluation of the Depositional Environment of the Eagle Ford
Louisiana State University LSU Digital Commons LSU Master's Theses Graduate School 2012 Evaluation of the depositional environment of the Eagle Ford Formation using well log, seismic, and core data in the Hawkville Trough, LaSalle and McMullen counties, south Texas Zachary Paul Hendershott Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_theses Part of the Earth Sciences Commons Recommended Citation Hendershott, Zachary Paul, "Evaluation of the depositional environment of the Eagle Ford Formation using well log, seismic, and core data in the Hawkville Trough, LaSalle and McMullen counties, south Texas" (2012). LSU Master's Theses. 863. https://digitalcommons.lsu.edu/gradschool_theses/863 This Thesis is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Master's Theses by an authorized graduate school editor of LSU Digital Commons. For more information, please contact [email protected]. EVALUATION OF THE DEPOSITIONAL ENVIRONMENT OF THE EAGLE FORD FORMATION USING WELL LOG, SEISMIC, AND CORE DATA IN THE HAWKVILLE TROUGH, LASALLE AND MCMULLEN COUNTIES, SOUTH TEXAS A Thesis Submitted to the Graduate Faculty of the Louisiana State University Agricultural and Mechanical College in partial fulfillment of the requirements for degree of Master of Science in The Department of Geology and Geophysics by Zachary Paul Hendershott B.S., University of the South – Sewanee, 2009 December 2012 ACKNOWLEDGEMENTS I would like to thank my committee chair and advisor, Dr. Jeffrey Nunn, for his constant guidance and support during my academic career at LSU. -
A Revision of the Classification of the Plesiosauria with a Synopsis of the Stratigraphical and Geographical Distribution Of
LUNDS UNIVERSITETS ARSSKRIFT. N. F. Avd. 2. Bd 59. Nr l. KUNGL. FYSIOGRAFISKA SÅLLSKAPETS HANDLINGAR, N. F. Bd 74. Nr 1. A REVISION OF THE CLASSIFICATION OF THE PLESIOSAURIA WITH A SYNOPSIS OF THE STRATIGRAPHICAL AND GEOGRAPHICAL DISTRIBUTION OF THE GROUP BY PER OVE PERSSON LUND C. W. K. GLEER UP Read before the Royal Physiographic Society, February 13, 1963. LUND HÅKAN OHLSSONS BOKTRYCKERI l 9 6 3 l. Introduction The sub-order Plesiosauria is one of the best known of the Mesozoic Reptile groups, but, as emphasized by KuHN (1961, p. 75) and other authors, its classification is still not satisfactory, and needs a thorough revision. The present paper is an attempt at such a revision, and includes also a tabular synopsis of the stratigraphical and geo graphical distribution of the group. Some of the species are discussed in the text (pp. 17-22). The synopsis is completed with seven maps (figs. 2-8, pp. 10-16), a selective synonym list (pp. 41-42), and a list of rejected species (pp. 42-43). Some forms which have been erroneously referred to the Plesiosauria are also briefly mentioned ("Non-Plesiosaurians", p. 43). - The numerals in braekets after the generic and specific names in the text refer to the tabular synopsis, in which the different forms are numbered in successional order. The author has exaroined all material available from Sweden, Australia and Spitzbergen (PERSSON 1954, 1959, 1960, 1962, 1962a); the major part of the material from the British Isles, France, Belgium and Luxembourg; some of the German spec imens; certain specimens from New Zealand, now in the British Museum (see LYDEK KER 1889, pp. -
ONTOGENIA DE Iguana Iguana (Linnaeus, 1758): ESTÁGIOS EMBRIONÁRIOS E DESENVOLVIMENTO DO ESQUELETO
UNIVERSIDADE DE BRASÍLIA Instituto de Ciências Biológicas Programa de Pós-Graduação em Biologia Animal ONTOGENIA DE Iguana iguana (Linnaeus, 1758): ESTÁGIOS EMBRIONÁRIOS E DESENVOLVIMENTO DO ESQUELETO DOUTORANDO: FABIANO CAMPOS LIMA ORIENTADOR: DR. ANTONIO SEBBEN BRASÍLIA – DF JUNHO, 2015 ONTOGENIA DE Iguana iguana (Linnaeus, 1758): ESTÁGIOS EMBRIONÁRIOS E DESENVOLVIMENTO DO ESQUELETO FABIANO CAMPOS LIMA Tese apresentada ao Programa de Pós- Graduação em Biologia Animal do Instituto de Ciências Biológicas da Universidade de Brasília com requisito parcial para obtenção do título de Doutor em Biologia Animal. ORIENTADOR: DR. ANTONIO SEBBEN BRASÍLIA – DF JUNHO, 2015 UNIVERSIDADE DE BRASÍLIA Instituto de Ciências Biológicas Programa de Pós-Graduação em Biologia Animal FABIANO CAMPOS LIMA Título da Tese Ontogenia de Iguana iguana (Linnaeus, 1758): Estágios Embrionários e Desenvolvimento do Esqueleto Prof. Dr. Antonio Sebben Presidente/Orientador UnB Prof. Dr. Eduardo Maurício Mendes de Lima Profa. Dra. Lilian Gimenes Giugliano Membro Efetivo Externo Membro Efetivo Externo UnB UnB Profa. Dra. Aline Pic-Taylor Prof. Dr. Osmindo Rodrigues Pires Junior Membro Efetivo Interno Membro Efetivo Interno UnB UnB Profa. Dra. Jussara Rocha Ferreira Membro Suplente UnB Brasília, 23 de Junho de 2015 Existe um único caminho que nos leva a plenitude e a herança que o mundo nos permite: o conhecimento. AGRADECIMENTOS Nenhuma grande jornada pode ser concluída sem que muitos personagens tenham participado dela. Poder expressar gratidão por aqueles que tornaram sua trajetória mais exequível é motivo de satisfação, pois nem todos são gratos àqueles que o ajudaram a transpor as pedras em seu caminho. Sou imensamente grato ao meu orientador, o professor Antonio Sebben, que desde o primeiro dia depositou confiança em mim, um rapaz franzino que apareceu do nada com o objetivo de se tornar um doutor. -
On the Cranial Anatomy of the Polycotylid Plesiosaurs, Including New Material of Polycotylus Latipinnis, Cope, from Alabama F
Marshall University Marshall Digital Scholar Biological Sciences Faculty Research Biological Sciences 2004 On the cranial anatomy of the polycotylid plesiosaurs, including new material of Polycotylus latipinnis, Cope, from Alabama F. Robin O’Keefe Marshall University, [email protected] Follow this and additional works at: http://mds.marshall.edu/bio_sciences_faculty Part of the Animal Sciences Commons, and the Ecology and Evolutionary Biology Commons Recommended Citation O’Keefe, F. R. 2004. On the cranial anatomy of the polycotylid plesiosaurs, including new material of Polycotylus latipinnis, Cope, from Alabama. Journal of Vertebrate Paleontology 24(2):326–340. This Article is brought to you for free and open access by the Biological Sciences at Marshall Digital Scholar. It has been accepted for inclusion in Biological Sciences Faculty Research by an authorized administrator of Marshall Digital Scholar. For more information, please contact [email protected], [email protected]. ON THE CRANIAL ANATOMY OF THE POLYCOTYLID PLESIOSAURS, INCLUDING NEW MATERIAL OF POLYCOTYLUS LATIPINNIS, COPE, FROM ALABAMA F. ROBIN O’KEEFE Department of Anatomy, New York College of Osteopathic Medicine, Old Westbury, New York 11568, U.S.A., [email protected] ABSTRACT—The cranial anatomy of plesiosaurs in the family Polycotylidae (Reptilia: Sauropterygia) has received renewed attention recently because various skull characters are thought to indicate plesiosauroid, rather than plio- sauroid, affinities for this family. New data on the cranial anatomy of polycotylid plesiosaurs is presented, and is shown to compare closely to the structure of cryptocleidoid plesiosaurs. The morphology of known polycotylid taxa is reported and discussed, and a preliminary phylogenetic analysis is used to establish ingroup relationships of the Cryptocleidoidea. -
(Squamata: Mosasauridae) from the Late Cretaceous Of
C. R. Palevol 14 (2015) 483–493 Contents lists available at ScienceDirect Comptes Rendus Palevol www.sci encedirect.com General Palaeontology, Systematics and Evolution (Vertebrate Palaeontology) An halisaurine (Squamata: Mosasauridae) from the Late Cretaceous of Patagonia, with a preserved tympanic disc: Insights into the mosasaur middle ear Un halisauriné (Squamata : Mosasauridae) du Crétacé supérieur de Patagonie, à disque tympanique conservé : un aperc¸ u de l’oreille moyenne des mosasaures a,∗ b Marta S. Fernández , Marianella Talevi a CONICET - División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina b CONICET - Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro, Isidro Lobo y Belgrano, 8332 General Roca, Río Negro, Argentina a b s t r a c t a r t i c l e i n f o Article history: Halisaurinae is a subfamily of enigmatic, small- to medium-sized mosasauroids, which Received 15 September 2014 retain a mosaic of primitive and derived features. The first record of a South American Hal- Accepted after revision 13 May 2015 isaurus with precise stratigraphic information includes a quadrate carrying a tympanic disc together with twelve vertebrae, collected in the Late Maastrichtian of Jagüel Formation Handled by Nathalie Bardet in northern Patagonia (Argentina). The preservation of a tympanic disc allows exploring and discussing the mechanisms of sound transmission in these mosasauroids. The loca- Keywords: tion of the tympanic disc resembles that one formed by the extracolumella of aquatic Halisaurus turtles and at least one extant lizard. Based on morphological comparison of the middle Patagonia ear we discuss previous hypotheses on the modification of the tympanic middle ear system Late Maastrichtian of mosasauroids for underwater hearing, in a manner similar to that observed in aquatic Cretaceous turtles. -
Mesozoic Marine Reptile Palaeobiogeography in Response to Drifting Plates
ÔØ ÅÒÙ×Ö ÔØ Mesozoic marine reptile palaeobiogeography in response to drifting plates N. Bardet, J. Falconnet, V. Fischer, A. Houssaye, S. Jouve, X. Pereda Suberbiola, A. P´erez-Garc´ıa, J.-C. Rage, P. Vincent PII: S1342-937X(14)00183-X DOI: doi: 10.1016/j.gr.2014.05.005 Reference: GR 1267 To appear in: Gondwana Research Received date: 19 November 2013 Revised date: 6 May 2014 Accepted date: 14 May 2014 Please cite this article as: Bardet, N., Falconnet, J., Fischer, V., Houssaye, A., Jouve, S., Pereda Suberbiola, X., P´erez-Garc´ıa, A., Rage, J.-C., Vincent, P., Mesozoic marine reptile palaeobiogeography in response to drifting plates, Gondwana Research (2014), doi: 10.1016/j.gr.2014.05.005 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT Mesozoic marine reptile palaeobiogeography in response to drifting plates To Alfred Wegener (1880-1930) Bardet N.a*, Falconnet J. a, Fischer V.b, Houssaye A.c, Jouve S.d, Pereda Suberbiola X.e, Pérez-García A.f, Rage J.-C.a and Vincent P.a,g a Sorbonne Universités CR2P, CNRS-MNHN-UPMC, Département Histoire de la Terre, Muséum National d’Histoire Naturelle, CP 38, 57 rue Cuvier, -
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comptes rendus palevol 2021 20 20 iles — Jean- pt Cl re au d d n e a R s a n g a e i — b i h P p a l a m e a o f b o i o y l h o p g a y r g a o n e d g p o i a l b a o e DIRECTEURS DE LA PUBLICATION / PUBLICATION DIRECTORS : Bruno David, Président du Muséum national d’Histoire naturelle Étienne Ghys, Secrétaire perpétuel de l’Académie des sciences RÉDACTEURS EN CHEF / EDITORS-IN-CHIEF : Michel Laurin (CNRS), Philippe Taquet (Académie des sciences) ASSISTANTE DE RÉDACTION / ASSISTANT EDITOR : Adenise Lopes (Académie des sciences ; [email protected]) MISE EN PAGE / PAGE LAYOUT : Fariza Sissi (Muséum national d’Histoire naturelle ; [email protected]) RÉVISIONS LINGUISTIQUES DES TEXTES ANGLAIS / ENGLISH LANGUAGE REVISIONS : Kevin Padian (University of California at Berkeley) RÉDACTEURS ASSOCIÉS / ASSOCIATE EDITORS : Micropaléontologie/Micropalaeontology Maria Rose Petrizzo (Università di Milano, Milano) Paléobotanique/Palaeobotany Cyrille Prestianni (Royal Belgian Institute of Natural Sciences, Brussels) Métazoaires/Metazoa Annalisa Ferretti (Università di Modena e Reggio Emilia, Modena) Paléoichthyologie/Palaeoichthyology Philippe Janvier (Muséum national d’Histoire naturelle, Académie des sciences, Paris) Amniotes du Mésozoïque/Mesozoic amniotes Hans-Dieter Sues (Smithsonian National Museum of Natural History, Washington) Tortues/Turtles Juliana Sterli (CONICET, Museo Paleontológico Egidio Feruglio, Trelew) Lépidosauromorphes/Lepidosauromorphs Hussam Zaher (Universidade de São Paulo) Oiseaux/Birds Eric Buffetaut (CNRS, École Normale Supérieure, Paris) Paléomammalogie (mammifères de moyenne et grande taille)/Palaeomammalogy (large and mid-sized mammals) Lorenzo Rook* (Università degli Studi di Firenze, Firenze) Paléomammalogie (petits mammifères sauf Euarchontoglires)/Palaeomammalogy (small mammals except for Euarchontoglires) Robert Asher (Cambridge University, Cambridge) Paléomammalogie (Euarchontoglires)/Palaeomammalogy (Euarchontoglires) K. -
Cranial Anatomy and Taxonomy of Dolichorhynchops Bonneri New
Marshall University Marshall Digital Scholar Biological Sciences Faculty Research Biological Sciences 2008 Cranial anatomy and taxonomy of Dolichorhynchops bonneri new combination, a polycotylid (Sauropterygia: Plesiosauria) from the Pierre Shale of Wyoming and South Dakota F. Robin O’Keefe Marshall University, [email protected] Follow this and additional works at: http://mds.marshall.edu/bio_sciences_faculty Part of the Animal Sciences Commons, and the Ecology and Evolutionary Biology Commons Recommended Citation O'Keefe, F. R. (2008). Cranial anatomy and taxonomy of Dolichorhynchops bonneri new combination, a polycotylid (Sauropterygia: Plesiosauria) from the Pierre Shale of Wyoming and South Dakota. Journal of Vertebrate Paleontology, 28(3), 664-676. This Article is brought to you for free and open access by the Biological Sciences at Marshall Digital Scholar. It has been accepted for inclusion in Biological Sciences Faculty Research by an authorized administrator of Marshall Digital Scholar. For more information, please contact [email protected], [email protected]. CRANIAL ANATOMY AND TAXONOMY OF DOLICHORHYNCHOPS BONNERI NEW COMBINATION, A POLYCOTYLID (SAUROPTERYGIA: PLESIOSAURIA) FROM THE PIERRE SHALE OF WYOMING AND SOUTH DAKOTA F. ROBIN O’KEEFE ABSTRACT The taxonomic identity of two well-preserved polycotylid plesiosaur skeletons from the Pierre Shale of far northern Wyoming and southern South Dakota has been controversial since their discovery. Originally referred to Dolichorhynchops osborni, the material was almost immediate-ly christened Trinacromerum bonneri Adams 1997; more recently the material has been referred to Polycotylus. Recent preparation of the well-preserved skull of one specimen permits detailed examination of the cranial morphology of this animal for the first time, and allows for its inclusion in a cladistic analysis of the Polycotylidae. -
Morphologic and Ontogenetic Patterns in Elasmosaur Neck Length, with Comments on the Taxonomic Utility of Neck Length Variables F
Marshall University Marshall Digital Scholar Biological Sciences Faculty Research Biological Sciences 6-2006 Morphologic and Ontogenetic Patterns in Elasmosaur Neck Length, with Comments on the Taxonomic Utility of Neck Length Variables F. Robin O’Keefe Marshall University, [email protected] Norton Hiller Follow this and additional works at: http://mds.marshall.edu/bio_sciences_faculty Part of the Aquaculture and Fisheries Commons, and the Ecology and Evolutionary Biology Commons Recommended Citation O’Keefe FR, Hiller N (2006) Morphologic and ontogenetic patterns in elasmosaur neck length, with comments on the taxonomic utility of neck length variables. Paludicola 5:206–229. This Article is brought to you for free and open access by the Biological Sciences at Marshall Digital Scholar. It has been accepted for inclusion in Biological Sciences Faculty Research by an authorized administrator of Marshall Digital Scholar. For more information, please contact [email protected], [email protected]. Paludicola 5(4):206-229 June 2006 by the Rochester Institute of Vertebrate Paleontology MORPHOLOGIC AND ONTOGENETIC PATTERNS IN ELASMOSAUR NECK LENGTH, WITH COMMENTS ON THE TAXONOMIC UTILITY OF NECK LENGTH VARIABLES F. Robin O'Keefe1 and Norton Hiller2 1Department of Anatomy, NYCOM 2 rm. 321, New York College of Osteopathic Medicine Old Westbury, New York 11568, [email protected] 2Canterbury Museum, Rolleston Avenue Christchurch, 8001 New Zealand, [email protected] ABSTRACT Elasmosaur cervical vertebrae are common fossils, but their taxonomic utility is limited due to a lack of understanding concerning their shape within and among taxa. In this paper, we analyze data from complete elasmosaur necks in an attempt to quantify and understand the variation in centrum dimensions.