(Diapsida: Saurosphargidae), with Implications for the Morphological Diversity and Phylogeny of the Group
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Cranial Anatomy, Taxonomic Implications
[Palaeontology, Vol. 55, Part 4, 2012, pp. 743–773] CRANIAL ANATOMY, TAXONOMIC IMPLICATIONS AND PALAEOPATHOLOGY OF AN UPPER JURASSIC PLIOSAUR (REPTILIA: SAUROPTERYGIA) FROM WESTBURY, WILTSHIRE, UK by JUDYTH SASSOON1, LESLIE F. NOE` 2 and MICHAEL J. BENTON1* 1School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen’s Road, Bristol BS8 1RJ, UK; e-mails: [email protected], [email protected] 2Geociencias, departamento de Fisica, Universidad de los Andes, Bogota´ DC, Colombia; e-mail: [email protected] *Corresponding author. Typescript received 5 December 2010; accepted in revised form 6 April 2011 Abstract: Complete skulls of giant marine reptiles of the genera. The two Westbury Pliosaurus specimens share many Late Jurassic are rare, and so the discovery of the 1.8-m- features, including the form of the teeth, but marked differ- long skull of a pliosaur from the Kimmeridge Clay Forma- ences in the snout and parietal crest suggest sexual dimor- tion (Kimmeridgian) of Westbury, Wiltshire, UK, is an phism; the present specimen is probably female. The large important find. The specimen shows most of the cranial size of the animal, the extent of sutural fusion and the and mandibular anatomy, as well as a series of pathological pathologies suggest this is an ageing individual. An erosive conditions. It was previously referred to Pliosaurus brachy- arthrotic condition of the articular glenoids led to pro- spondylus, but it can be referred reliably only to the genus longed jaw misalignment, generating a suite of associated Pliosaurus, because species within the genus are currently in bone and dental pathologies. -
Foramina in Plesiosaur Cervical Centra Indicate a Specialized Vascular System
Foss. Rec., 20, 279–290, 2017 https://doi.org/10.5194/fr-20-279-2017 © Author(s) 2017. This work is distributed under the Creative Commons Attribution 4.0 License. Foramina in plesiosaur cervical centra indicate a specialized vascular system Tanja Wintrich1, Martin Scaal2, and P. Martin Sander1 1Bereich Paläontologie, Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Universität Bonn, 53115 Bonn, Germany 2Institut für Anatomie II, Universität zu Köln, Joseph-Stelzmann-Str. 9, 50937 Cologne, Germany Correspondence: Tanja Wintrich ([email protected]) Received: 16 August 2017 – Revised: 13 November 2017 – Accepted: 14 November 2017 – Published: 19 December 2017 Abstract. The sauropterygian clade Plesiosauria arose in the 1 Introduction Late Triassic and survived to the very end of the Cretaceous. A long, flexible neck with over 35 cervicals (the highest 1.1 Sauropterygian evolution and plesiosaur origins number of cervicals in any tetrapod clade) is a synapomor- phy of Pistosauroidea, the clade that contains Plesiosauria. Plesiosauria are Mesozoic marine reptiles that had a global Basal plesiosaurians retain this very long neck but greatly distribution almost from their origin in the Late Triassic reduce neck flexibility. In addition, plesiosaurian cervicals (Benson et al., 2012) to their extinction at the end of the have large, paired, and highly symmetrical foramina on the Cretaceous (Ketchum and Benson, 2010; Fischer et al., ventral side of the centrum, traditionally termed “subcentral 2017). Plesiosauria belong to the clade Sauropterygia and foramina”, and on the floor of the neural canal. We found are its most derived and only post-Triassic representatives, that these dorsal and the ventral foramina are connected by being among the most taxonomically diverse of all Meso- a canal that extends across the center of ossification of the zoic marine reptiles (Motani, 2009). -
O'keefe, F. R. 2006
12 Neoteny and the Plesiomorphic Condition of the Plesiosaur Basicranium F. Robin O’Keefe Introduction Historically, the systematics of the Plesiosauria (Reptilia, Sauroptery- gia) were based largely on postcranial characters (Persson, 1963; Brown, 1981). Several factors account for this bias: plesiosaur skulls tend to be del- icate and are often crushed even when preserved, postcranial elements are relatively common and cranial elements are not, lack of knowledge about the relationships of stem-group sauropterygians, and lack of knowledge of plesiosaur cranial anatomy itself. However, recent detailed examinations of plesiosaur cranial anatomy have identified many characters of use in plesiosaur systematics (Brown, 1993; Cruickshank, 1994; Storrs & Taylor, 1996; Storrs, 1997; Carpenter, 1997; Evans, 1999; O’Keefe, 2001, 2004), and the systematics of the group have changed markedly in response (Carpenter, 1997; O’Keefe, 2001, 2004). The work of Rieppel and others has clarified the anatomy and relationships of stem-group sauropterygians (Storrs, 1991; see Rieppel, 2000, for review). This work has laid the anatomic and phylogenetic foundations for a better understanding of ple- siosaur cranial anatomy. The purpose of this paper is to describe the condition of the braincase in stratigraphically early and morphologically primitive plesiosaurs. In- formation on the braincase of plesiomorphic taxa is important because it establishes the polarity of characters occurring in more derived ple- siosaurs. This paper begins with a short review of braincase anatomy in stem-group sauropterygians. Data on braincase morphology of the ple- siomorphic plesiosaur genera Thalassiodracon and Eurycleidus are then presented and interpreted via comparison with other plesiosaurs, stem- group sauropterygians, and stem diapsids (Araeoscelis). -
A New Species of the Sauropsid Reptile Nothosaurus from the Lower Muschelkalk of the Western Germanic Basin, Winterswijk, the Netherlands
A new species of the sauropsid reptile Nothosaurus from the Lower Muschelkalk of the western Germanic Basin, Winterswijk, The Netherlands NICOLE KLEIN and PAUL C.H. ALBERS Klein, N. and Albers, P.C.H. 2009. A new species of the sauropsid reptile Nothosaurus from the Lower Muschelkalk of the western Germanic Basin, Winterswijk, The Netherlands. Acta Palaeontologica Polonica 54 (4): 589–598. doi:10.4202/ app.2008.0083 A nothosaur skull recently discovered from the Lower Muschelkalk (early Anisian) locality of Winterswijk, The Nether− lands, represents at only 46 mm in length the smallest nothosaur skull known today. It resembles largely the skull mor− phology of Nothosaurus marchicus. Differences concern beside the size, the straight rectangular and relative broad parietals, the short posterior extent of the maxilla, the skull proportions, and the overall low number of maxillary teeth. In spite of its small size, the skull can not unequivocally be interpreted as juvenile. It shows fused premaxillae, nasals, frontals, and parietals, a nearly co−ossified jugal, and fully developed braincase elements, such as a basisphenoid and mas− sive epipterygoids. Adding the specimen to an existing phylogenetic analysis shows that it should be assigned to a new species, Nothosaurus winkelhorsti sp. nov., at least until its juvenile status can be unequivocally verified. Nothosaurus winkelhorsti sp. nov. represents, together with Nothosaurus juvenilis, the most basal nothosaur, so far. Key words: Sauropterygia, Nothosaurus, ontogeny, Anisian, The Netherlands. Nicole Klein [nklein@uni−bonn.de], Steinmann−Institut für Geologie, Mineralogie und Paläontologie, Universtät Bonn, Nußallee 8, 53115 Bonn, Germany; Paul C.H. Albers [[email protected]], Naturalis, Nationaal Natuurhistorisch Museum, Darwinweg 2, 2333 CR Leiden, The Netherlands. -
The Endoskeletal Origin of the Turtle Carapace
ARTICLE Received 7 Dec 2012 | Accepted 3 Jun 2013 | Published 9 Jul 2013 DOI: 10.1038/ncomms3107 OPEN The endoskeletal origin of the turtle carapace Tatsuya Hirasawa1, Hiroshi Nagashima2 & Shigeru Kuratani1 The turtle body plan, with its solid shell, deviates radically from those of other tetrapods. The dorsal part of the turtle shell, or the carapace, consists mainly of costal and neural bony plates, which are continuous with the underlying thoracic ribs and vertebrae, respectively. Because of their superficial position, the evolutionary origins of these costo-neural elements have long remained elusive. Here we show, through comparative morphological and embryological analyses, that the major part of the carapace is derived purely from endos- keletal ribs. We examine turtle embryos and find that the costal and neural plates develop not within the dermis, but within deeper connective tissue where the rib and intercostal muscle anlagen develop. We also examine the fossils of an outgroup of turtles to confirm that the structure equivalent to the turtle carapace developed independently of the true osteoderm. Our results highlight the hitherto unravelled evolutionary course of the turtle shell. 1 Laboratory for Evolutionary Morphology, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan. 2 Division of Gross Anatomy and Morphogenesis, Department of Regenerative and Transplant Medicine, Niigata University, Niigata 951-8510, Japan. Correspondence and requests for materials should be addressed to T.H. (email: [email protected]). NATURE COMMUNICATIONS | 4:2107 | DOI: 10.1038/ncomms3107 | www.nature.com/naturecommunications 1 & 2013 Macmillan Publishers Limited. All rights reserved. ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/ncomms3107 wo types of skeletal systems are recognized in vertebrates, exoskeletal components into the costal and neural plates (Fig. -
Description of an Unusual Cervical Vertebral Column of a Plesiosaur from the Kiowa Shale Ian N
Fort Hays State University FHSU Scholars Repository Master's Theses Graduate School Spring 2014 Description of an Unusual Cervical Vertebral Column of a Plesiosaur from the Kiowa Shale Ian N. Cost Fort Hays State University Follow this and additional works at: https://scholars.fhsu.edu/theses Part of the Biology Commons Recommended Citation Cost, Ian N., "Description of an Unusual Cervical Vertebral Column of a Plesiosaur from the Kiowa Shale" (2014). Master's Theses. 57. https://scholars.fhsu.edu/theses/57 This Thesis is brought to you for free and open access by the Graduate School at FHSU Scholars Repository. It has been accepted for inclusion in Master's Theses by an authorized administrator of FHSU Scholars Repository. DESCRIPTION OF AN UNUSUAL CERVICAL VERTEBRAL COLUMN OF A PLESIOSAUR FROM THE KIOWA SHALE being A Thesis Presented to the Graduate Faculty of the Fort Hays State University in Partial Fulfillment of the Requirements for the Degree of Master of Science by Ian Cost B.A., Bridgewater State University M.Ed., Lesley University Date_____________________ Approved________________________________ Major Professor Approved________________________________ Chair, Graduate Council This Thesis for The Master of Science Degree By Ian Cost Has Been Approved __________________________________ Chair, Supervisory Committee __________________________________ Supervisory Committee __________________________________ Supervisory Committee __________________________________ Supervisory Committee __________________________________ Supervisory Committee __________________________________ Chair, Department of Biological Science i PREFACE This manuscript has been formatted in the style of the Journal of Vertebrate Paleontology. Keywords: plesiosaur, polycotylid, cervical vertebrae, Dolichorhynchops, Trinacromerum ii ABSTRACT The Early Cretaceous (Albian) Kiowa Shale of Clark County, Kansas consists mainly of dark gray shale with occasional limestone deposits that represent a near shore environment. -
Reptiles A. Cladistics 1. Many Groups of Organisms
Reptiles A. Cladistics 1. Many groups of organisms are “polyphyletic” a. This means that the group combines 2 or more lineages - example=fish 2. Cladistics follows only pure lineages going back in time - example Osteichthys B. Reptile Classifiecation - looks like a polyphyletic group 1. Dry skin - no loss of water through skin like amphibians 2. Aminotic egg - an egg that can survive on dry land - in contrast with the amphibian egg C. Mammals and Birds are derived from different lineages of reptiles (We will see below) D. Stem Reptiles 1. Different lineages based on the temporal region of their skulls - number of holes (or bars) a. These holes are necessary to accommodate large jaw muscles b. Anapsid Skull - no holes in temporal - jaws can move fast, but with little force 1. Muscles that move the jaw are small 2. There is no good paleotological evidence for the transition between amphibians and reptiles - no fossil intermediates a. Fossil amphibians have lots of dermal bones in skull b. Amphibians have no temporal openings in skull 1. (Aside) both fossil amphibians and primitive reptiles have a parietal “eye” that senses light and dark (“third” eye in middle of head) c. Reptile skull is higher than amphibian to accomodate larger jaw muscles d. Of the modern reptiles only turtles are anapsids 2. Diapsid Skull - has holes in the temporal region a. Diapsid reptiles gave rise to lizards and snakes - they have a diapsid skull 1. Also Tuatara, crocodiles, dinosaurs and pterydactyls Reptiles b. One group of diapsids also had a pre-orbital hole in the skull in front of eye - this hole is still preserved in the birds - this anatomy suggests strongly that the birds are derived from the diapsid reptiles 3. -
Origin and Beyond
EVOLUTION ORIGIN ANDBEYOND Gould, who alerted him to the fact the Galapagos finches ORIGIN AND BEYOND were distinct but closely related species. Darwin investigated ALFRED RUSSEL WALLACE (1823–1913) the breeding and artificial selection of domesticated animals, and learned about species, time, and the fossil record from despite the inspiration and wealth of data he had gathered during his years aboard the Alfred Russel Wallace was a school teacher and naturalist who gave up teaching the anatomist Richard Owen, who had worked on many of to earn his living as a professional collector of exotic plants and animals from beagle, darwin took many years to formulate his theory and ready it for publication – Darwin’s vertebrate specimens and, in 1842, had “invented” the tropics. He collected extensively in South America, and from 1854 in the so long, in fact, that he was almost beaten to publication. nevertheless, when it dinosaurs as a separate category of reptiles. islands of the Malay archipelago. From these experiences, Wallace realized By 1842, Darwin’s evolutionary ideas were sufficiently emerged, darwin’s work had a profound effect. that species exist in variant advanced for him to produce a 35-page sketch and, by forms and that changes in 1844, a 250-page synthesis, a copy of which he sent in 1847 the environment could lead During a long life, Charles After his five-year round the world voyage, Darwin arrived Darwin saw himself largely as a geologist, and published to the botanist, Joseph Dalton Hooker. This trusted friend to the loss of any ill-adapted Darwin wrote numerous back at the family home in Shrewsbury on 5 October 1836. -
HOVASAURUS BOULEI, an AQUATIC EOSUCHIAN from the UPPER PERMIAN of MADAGASCAR by P.J
99 Palaeont. afr., 24 (1981) HOVASAURUS BOULEI, AN AQUATIC EOSUCHIAN FROM THE UPPER PERMIAN OF MADAGASCAR by P.J. Currie Provincial Museum ofAlberta, Edmonton, Alberta, T5N OM6, Canada ABSTRACT HovasauTUs is the most specialized of four known genera of tangasaurid eosuchians, and is the most common vertebrate recovered from the Lower Sakamena Formation (Upper Per mian, Dzulfia n Standard Stage) of Madagascar. The tail is more than double the snout-vent length, and would have been used as a powerful swimming appendage. Ribs are pachyostotic in large animals. The pectoral girdle is low, but massively developed ventrally. The front limb would have been used for swimming and for direction control when swimming. Copious amounts of pebbles were swallowed for ballast. The hind limbs would have been efficient for terrestrial locomotion at maturity. The presence of long growth series for Ho vasaurus and the more terrestrial tan~saurid ThadeosauTUs presents a unique opportunity to study differences in growth strategies in two closely related Permian genera. At birth, the limbs were relatively much shorter in Ho vasaurus, but because of differences in growth rates, the limbs of Thadeosau rus are relatively shorter at maturity. It is suggested that immature specimens of Ho vasauTUs spent most of their time in the water, whereas adults spent more time on land for mating, lay ing eggs and/or range dispersal. Specilizations in the vertebrae and carpus indicate close re lationship between Youngina and the tangasaurids, but eliminate tangasaurids from consider ation as ancestors of other aquatic eosuchians, archosaurs or sauropterygians. CONTENTS Page ABREVIATIONS . ..... ... ......... .......... ... ......... ..... ... ..... .. .... 101 INTRODUCTION . -
A New Plesiosaur from the Lower Jurassic of Portugal and the Early Radiation of Plesiosauroidea
A new plesiosaur from the Lower Jurassic of Portugal and the early radiation of Plesiosauroidea EDUARDO PUÉRTOLAS-PASCUAL, MIGUEL MARX, OCTÁVIO MATEUS, ANDRÉ SALEIRO, ALEXANDRA E. FERNANDES, JOÃO MARINHEIRO, CARLA TOMÁS, and SIMÃO MATEUS Puértolas-Pascual, E., Marx, M., Mateus, O., Saleiro, A., Fernandes, A.E., Marinheiro, J., Tomás, C. and Mateus, S. 2021. A new plesiosaur from the Lower Jurassic of Portugal and the early radiation of Plesiosauroidea. Acta Palaeontologica Polonica 66 (2): 369–388. A new plesiosaur partial skeleton, comprising most of the trunk and including axial, limb, and girdle bones, was collected in the lower Sinemurian (Coimbra Formation) of Praia da Concha, near São Pedro de Moel in central west Portugal. The specimen represents a new genus and species, Plesiopharos moelensis gen. et sp. nov. Phylogenetic analysis places this taxon at the base of Plesiosauroidea. Its position is based on this exclusive combination of characters: presence of a straight preaxial margin of the radius; transverse processes of mid-dorsal vertebrae horizontally oriented; ilium with sub-circular cross section of the shaft and subequal anteroposterior expansion of the dorsal blade; straight proximal end of the humerus; and ventral surface of the humerus with an anteroposteriorly long shallow groove between the epipodial facets. In addition, the new taxon has the following autapomorphies: iliac blade with less expanded, rounded and convex anterior flank; highly developed ischial facet of the ilium; apex of the neural spine of the first pectoral vertebra inclined posterodorsally with a small rounded tip. This taxon represents the most complete and the oldest plesiosaur species in the Iberian Peninsula. -
The First Possible Choristoderan Trackway from the Lower
www.nature.com/scientificreports OPEN The frst possible choristoderan trackway from the Lower Cretaceous Daegu Formation of South Korea and its implications on choristoderan locomotion Yuong‑Nam Lee1*, Dal‑Yong Kong2 & Seung‑Ho Jung2 Here we report a new quadrupedal trackway found in the Lower Cretaceous Daegu Formation (Albian) in the vicinity of Ulsan Metropolitan City, South Korea, in 2018. A total of nine manus‑pes imprints show a strong heteropodous quadrupedal trackway (length ratio is 1:3.36). Both manus and pes tracks are pentadactyl with claw marks. The manus prints rotate distinctly outward while the pes prints are nearly parallel to the direction of travel. The functional axis in manus and pes imprints suggests that the trackmaker moved along the medial side during the stroke progressions (entaxonic), indicating weight support on the inner side of the limbs. There is an indication of webbing between the pedal digits. These new tracks are assigned to Novapes ulsanensis, n. ichnogen., n. ichnosp., which are well‑matched not only with foot skeletons and body size of Monjurosuchus but also the fossil record of choristoderes in East Asia, thereby N. ulsanensis could be made by a monjurosuchid‑like choristoderan and represent the frst possible choristoderan trackway from Asia. N. ulsanensis also suggests that semi‑aquatic choristoderans were capable of walking semi‑erect when moving on the ground with a similar locomotion pattern to that of crocodilians on land. South Korea has become globally famous for various tetrapod footprints from Cretaceous strata1, among which some clades such as frogs2, birds3 and mammals4 have been proved for their existences only with ichnological evidence. -
Tiago Rodrigues Simões
Diapsid Phylogeny and the Origin and Early Evolution of Squamates by Tiago Rodrigues Simões A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in SYSTEMATICS AND EVOLUTION Department of Biological Sciences University of Alberta © Tiago Rodrigues Simões, 2018 ABSTRACT Squamate reptiles comprise over 10,000 living species and hundreds of fossil species of lizards, snakes and amphisbaenians, with their origins dating back at least as far back as the Middle Jurassic. Despite this enormous diversity and a long evolutionary history, numerous fundamental questions remain to be answered regarding the early evolution and origin of this major clade of tetrapods. Such long-standing issues include identifying the oldest fossil squamate, when exactly did squamates originate, and why morphological and molecular analyses of squamate evolution have strong disagreements on fundamental aspects of the squamate tree of life. Additionally, despite much debate, there is no existing consensus over the composition of the Lepidosauromorpha (the clade that includes squamates and their sister taxon, the Rhynchocephalia), making the squamate origin problem part of a broader and more complex reptile phylogeny issue. In this thesis, I provide a series of taxonomic, phylogenetic, biogeographic and morpho-functional contributions to shed light on these problems. I describe a new taxon that overwhelms previous hypothesis of iguanian biogeography and evolution in Gondwana (Gueragama sulamericana). I re-describe and assess the functional morphology of some of the oldest known articulated lizards in the world (Eichstaettisaurus schroederi and Ardeosaurus digitatellus), providing clues to the ancestry of geckoes, and the early evolution of their scansorial behaviour.