DOCSLIB.ORG

The Herefordshire Lagerstätte: Fleshing out Silurian Marine Life

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Herefordshire Lagerstätte: Fleshing out Silurian Marine Life Downloaded from http://jgs.lyellcollection.org/ by guest on September 26, 2021 Review Focus Journal of the Geological Society Published Online First https://doi.org/10.1144/jgs2019-110 The Herefordshire Lagerstätte: fleshing out Silurian marine life Derek J. Siveter1,2*, Derek E. G. Briggs3, David J. Siveter4 & Mark D. Sutton5 1 Earth Collections, University Museum of Natural History, Oxford OX1 3PW, UK 2 Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK 3 Department of Geology and Geophysics and Yale Peabody Museum of Natural History, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA 4 School of Geography, Geology and the Environment, University of Leicester, Leicester LE1 7RH, UK 5 Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK DeJS, 0000-0002-5305-2192; DEGB, 0000-0003-0649-6417; DaJS, 0000-0002-1716-5819; MDS, 0000-0002-7137-7572 * Correspondence: [email protected] Abstract: The Herefordshire Lagerstätte (c. 430 Ma) from the UK is a rare example of soft-tissue preservation in the Silurian. It yields a wide range of invertebrates in unparalleled three-dimensional detail, dominated by arthropods and sponges. The fossils are exceptionally preserved as calcitic void infills in early diagenetic carbonate concretions within a volcaniclastic (bentonite) horizon. The Lagerstätte occurs in an outer shelf/upper slope setting in the Welsh Basin, which was located on Avalonia in the southern subtropics. The specimens are investigated by serial grinding, digital photography and rendering in the round as ‘virtual fossils’ by computer. The fossils contribute much to our understanding of the palaeobiology and early history of the groups represented. They are important in demonstrating unusual character combinations that illuminate relationships; in calibrating molecular clocks; in variously linking with taxa in both earlier and later Paleozoic Lagerstätten; and in providing evidence of the early evolution of crown-group representatives of several groups. Received 9 July 2019; revised 19 August 2019; accepted 21 August 2019 The Herefordshire Lagerstätte is unique in preserving representa- bentonite is unique in the British stratigraphic record, at least, in tives of many major invertebrate groups in high-fidelity 3-D, as reaching a thickness of more than 1 m in places. The bentonite was calcite in-fills within concretions in a marine volcaniclastic deposit. deposited within mudstones of the Wenlock Series Coalbrookdale The Herefordshire fossils are unimpressive at first sight, yet they Formation (Fig. 1d), which rests on the slightly older Dolyhir and yield unrivalled evidence about the palaeobiology and evolutionary Nash Scar Limestone Formation. In the Dolyhir region these coral significance of Silurian animals. They provide, for example, the and algal-rich limestones lie with angular unconformity on a earliest evidence for the time of origin of certain major crown- Precambrian sedimentary basement (Woodcock 1993). At nearby groups (i.e. the living biota), for instance sea spiders (pycnogonids). Nash Scar, laterally equivalent carbonates sit, possibly disconform- The locality lies in the Welsh Borderland, a historic region central ably (Woodcock 1993), on the shallow-marine, upper Llandovery to R. I. Murchison’s pioneering research which established the Series Folly Sandstone Formation and a hardground is developed Silurian System in the 1830s. In 1990 Bob King, mineralogist and locally on the limestones (Hurst et al. 1978). retired Curator in the Department of Geology at the University of The host bentonite lies approximately at the boundary between Leicester, collected concretions in float from the locality and the Sheinwoodian and Homerian stages (Fig. 1d), which is presented nine of them to the Leicester collections. Curator Roy radiometrically constrained to 430.5 ± 0.7 Ma (Cohen et al. 2013, Clements asked David Siveter to examine one of the concretions updated 2018). Various evidence from brachiopods, graptolites and when he was accessioning the material in 1994. What David conodonts indicates a Wenlock age for the Dolyhir and Nash Scar recognized under the microscope, an arthropod with preserved Limestone Formation in addition to the overlying Coalbrookdale limbs (later named Offacolus kingi), was confirmed by Derek Formation (Bassett 1974; Cocks et al. 1992). The Sheinwoodian Siveter and, together with Bob King, they identified the conodont Ozarkodina sagitta rhenana has been recovered from the stratigraphic horizon and collected more concretions. In 1995 limestones at Dolyhir and Nash Scar (Bassett 1974; Aldridge et al. Derek Briggs joined the team and, following more visits to the 1981). The presence of Homerian Cyrtograptus lundgreni Biozone locality, we published an initial paper flagging the significance of graptolites in the Coalbrookdale Formation mudstones immediately the discovery (Briggs et al. 1996). NERC and Leverhulme Trust above the limestones at Nash Scar (Bassett 1974) suggests that funding enabled Patrick Orr and later Mark Sutton to work on the deposition of these mudstones did not commence locally until Lagerstätte, initially as postdoctoral researchers. The support and C. lundgreni times (Hurst et al. 1978). This is consistent with the co-operation of the site owners and help from English Nature have presence of the limestone hardground that presumably formed been crucial in realizing its scientific potential. during a hiatus in deposition in the late Sheinwoodian. The recovery of the chitinozoans Margachitina margaritana, Locality, age and palaeogeographical setting Ancyrochitina plurispinosa and Cingulochitina cingulata from 20 to 50 cm below the bentonite also indicates an upper Sheinwoodian The Herefordshire site lies in the Old Radnor to Presteigne area of to Homerian age for the Coalbrookdale Formation (G. Mullins, the Welsh Borderland (Fig. 1a) in the vicinity of the Church Stretton pers. comm. 2000; see also Steeman et al. 2015). That age is Fault Zone. The fossil-bearing concretions (Fig. 1b and c) occur in a unchallenged by ostracods (David Siveter, unpublished informa- soft, fine-grained, cream-coloured, weathered and largely uncon- tion) and radiolarians (Siveter et al. 2007a) recovered from solidated bentonite (Fig. 1b) that crops out over about 30 m. The concretions in the bentonite. © 2019 The Author(s). Published by The Geological Society of London. All rights reserved. For permissions: http://www.geolsoc.org.uk/permissions. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics Downloaded from http://jgs.lyellcollection.org/ by guest on September 26, 2021 D. J. Siveter et al. Fig. 1. Provenance and palaeogeography. (a) Welsh Borderland location of the Herefordshire Lagerstätte with regional geology. (b) The volcanic ash (bentonite), with concretions in situ, in contact with Coalbrookdale Formation shales above. (c) Typical concretion, 6 × 4 cm, concentrically weathered, lacking the blue-grey-hearted centre of calcium carbonate that is present in partially weathered examples, and incorporating an eccentric specimen of the aplacophoran Acaenoplax.(d) Local stratigraphy of the Dolyhir–Presteigne area. Radiometric dates are those given in Cohen et al. (2013, updated 2018), the International Commission on Stratigraphy (ICS) Chronostratigraphic Chart. Cramer et al. (2012) give marginally different radiometric dates for some of the boundaries based on sampling from Gotland and the West Midlands, UK, for example 429.5 Ma for the Sheinwoodian–Homerian boundary. However, the majority margin of error on these dates (±0.7 Ma) provides overlap with the dates given in the ICS Chronostratigraphic Chart. (e) Welsh Basin palaeogeography at approximately the Sheinwoodian–Homerian boundary (modified from Cherns et al. 2006, fig. 4.13a). (f) Eastern Laurussian palaeogeography during the Wenlock (modified from Cocks & Torsvik 2005, fig. 9). Downloaded from http://jgs.lyellcollection.org/ by guest on September 26, 2021 The Herefordshire Lagerstätte The volcanic ash in which the Herefordshire Lagerstätte is constituent of the void fill. Clay minerals precipitated on and preserved accumulated in the Welsh Basin (Fig. 1e). This lay on the underneath the exoskeleton, and in some examples the gut trace was microcontinent of Avalonia, which included southern Britain replicated in calcium phosphate. Ferroan dolomite (ankerite) formed (Fig. 1f; Cocks & Torsvik 2011). Avalonia and adjacent Baltica at a later stage perhaps coincident with the transformation on burial were in southern tropical/subtropical palaeolatitudes in the mid- of smectite to illite. Abundant radiolarians are evident on the surface Silurian, separated from Laurentia by a remnant Iapetus Ocean. of split concretions (Siveter et al. 2007a; Fig. 5x). Their Shallow-water muds characterized much of the Welsh Borderland preservation shows parallels to that of Offacolus (Orr et al. 2002). and central England east of the Church Stretton Fault Zone (Bassett Calcite and pyrite precipitated in the void vacated by the cytoplasm et al. 1992; Cherns et al. 2006). Coeval fine clastics and turbidites within the radiolarian tests; this space was not invaded by matrix. accumulated to the west in the deepest parts of the Welsh Basin. The precipitation of calcite retained the shape of the test when the Palaeogeographical and sedimentological evidence indicates that opaline silica that formed it was replaced during diagenesis by a the Coalbrookdale Formation in the
Load more

Recommended publications
  • Systematics , Zoogeography , Andecologyofthepriapu
    SYSTEMATICS, ZOOGEOGRAPHY, AND ECOLOGY OF THE PRIAPULIDA by J. VAN DER LAND (Rijksmuseum van Natuurlijke Historie, Leiden) With 89 text-figures and five plates CONTENTS Ι Introduction 4 1.1 Plan 4 1.2 Material and methods 5 1.3 Acknowledgements 6 2 Systematics 8 2.1 Historical introduction 8 2.2 Phylum Priapulida 9 2.2.1 Diagnosis 10 2.2.2 Classification 10 2.2.3 Definition of terms 12 2.2.4 Basic adaptive features 13 2.2.5 General features 13 2.2.6 Systematic notes 2 5 2.3 Key to the taxa 20 2.4 Survey of the taxa 29 Priapulidae 2 9 Priapulopsis 30 Priapulus 51 Acanthopriapulus 60 Halicryptus 02 Tubiluchidae 7° Tubiluchus 73 3 Zoogeography and ecology 84 3.1 Distribution 84 3.1.1 Faunistics 90 3.1.2 Expeditions 93 3.2 Ecology 96 3.2.1 Substratum 96 3.2.2 Depth 97 3.2.3 Temperature 97 3.24 Salinity 98 3.2.5 Oxygen 98 3.2.6 Food 99 3.2.7 Predators 100 3.2.8 Communities 102 3.3 Theoretical zoogeography 102 3.3.1 Bipolarity 102 3.3.2 Relict distribution 103 3.3.3 Concluding remarks 104 References 105 4 ZOOLOGISCHE VERHANDELINGEN 112 (1970) 1 INTRODUCTION The phylum Priapulida is only a very small group of marine worms but, since these animals apparently represent the last remnants of a once un- doubtedly much more important animal type, they are certainly of great scientific interest. Therefore, it is to be regretted that a comprehensive review of our present knowledge of the group does not exist, which does not only cause the faulty way in which the Priapulida are treated usually in textbooks and works on phylogeny, but also hampers further studies.
    [Show full text]
  • Download Abstract Booklet Session 4
    Abstract Volume 17th Swiss Geoscience Meeting Fribourg, 22nd + 23rd November 2019 4 Palaeontology 106 4. Palaeontology Torsten Scheyer, Christian Klug, Lionel Cavin Schweizerische Paläontologische Gesellschaft Kommission des Schweizerischen Paläontologischen Abhandlungen (KSPA) Symposium 4: Palaeontology TALKS: 4.1 Alleon J., Bernard S., Olivier N., Thomazo C., Marin-Carbonne J.: Molecular characteristics of organic microfossils in Paleoarchean cherts 4.2 Antcliffe J.B., Jessop W., Daley A.C.: Prey fractionation in the Archaeocyatha and its implication for the ecology of the first animal reef systems 4.3 Bastiaans D., Kroll J.F., Jagt J.W.M., Schulp A.S.: Cranial pathologies in a Late Cretaceous mosasaur from the Netherlands: behavioral and immunological implications. 4.4 Daley A.C., Antcliffe J.B., Lheritier M.: Understanding the fossil record of arthropod moulting using experimental taphonomic approaches 4.5 Dziomber L., Foth C., Joyce W.G.: A geometric morphometric study of turtle shells 4.6 Evers S.W.: A new hypothesis of turtle relationships provides insights into the evolution of marine adaptation, and turtle diversification 4.7 Fau M., Villier L., Ewin T.: Diversity of early Forcipulatacea (Asteroidea) 4.8 Ferrante C., Cavin L.: Weird coelacanths from the Triassic of Switzerland 4.9 Frey L., Coates M.I., Rücklin M., Klug C.: A new early symmoriid with an unusual jaw articulation from the Late Devonian of Morocco 4.10 Friesenbichler E., Hautmann M., Bucher H.: Palaeoecology of benthic macroinvertebrates from three Middle Triassic
    [Show full text]
  • Phylogenomic Resolution of Sea Spider Diversification Through Integration Of
    bioRxiv preprint doi: https://doi.org/10.1101/2020.01.31.929612; this version posted February 2, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Phylogenomic resolution of sea spider diversification through integration of multiple data classes 1Jesús A. Ballesteros†, 1Emily V.W. Setton†, 1Carlos E. Santibáñez López†, 2Claudia P. Arango, 3Georg Brenneis, 4Saskia Brix, 5Esperanza Cano-Sánchez, 6Merai Dandouch, 6Geoffrey F. Dilly, 7Marc P. Eleaume, 1Guilherme Gainett, 8Cyril Gallut, 6Sean McAtee, 6Lauren McIntyre, 9Amy L. Moran, 6Randy Moran, 5Pablo J. López-González, 10Gerhard Scholtz, 6Clay Williamson, 11H. Arthur Woods, 12Ward C. Wheeler, 1Prashant P. Sharma* 1 Department of Integrative Biology, University of Wisconsin–Madison, Madison, WI, USA 2 Queensland Museum, Biodiversity Program, Brisbane, Australia 3 Zoologisches Institut und Museum, Cytologie und Evolutionsbiologie, Universität Greifswald, Greifswald, Germany 4 Senckenberg am Meer, German Centre for Marine Biodiversity Research (DZMB), c/o Biocenter Grindel (CeNak), Martin-Luther-King-Platz 3, Hamburg, Germany 5 Biodiversidad y Ecología Acuática, Departamento de Zoología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain 6 Department of Biology, California State University-Channel Islands, Camarillo, CA, USA 7 Départment Milieux et Peuplements Aquatiques, Muséum national d’Histoire naturelle, Paris, France 8 Institut de Systématique, Emvolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Concarneau, France 9 Department of Biology, University of Hawai’i at Mānoa, Honolulu, HI, USA Page 1 of 31 bioRxiv preprint doi: https://doi.org/10.1101/2020.01.31.929612; this version posted February 2, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder.
    [Show full text]
  • Yale Earth & Planetary Sciences News
    YALE EARTH & PLANETARY SCIENCES NEWS Yale University I Department of Earth & Planetary Sciences FALL NEWSLETTER 2020 Since our last newsletter (in Chair’s Letter 2018) we have added two new faculty, Assistant Profes- sors Juan Lora and Lidya Dear Friends, Family and Tarhan. Juan studies plan- Alumni of Yale Earth etary atmospheres and & Planetary Sciences, climates, and is one of the principal investigators on the Surely one of the first upcoming NASA Dragonfly things you’ll notice, espe- Mission to the Saturnian moon cially you alumni, is that Juan Lora, Assistant Titan. Titan is one of the big- the department changed Professor gest moons in our solar sys- its name. On July 1, 2020 tem, is the only one with a thick atmosphere made the department went from of mostly nitrogen, and has a methane cycle similar Geology & Geophysics to Earth’s hydrological cycle, which carries water to Earth & Planetary Sci- and heat around our planet. Juan also examines Dave Bercovici ences. This change has how a warming climate on Earth affects water been brewing for decades, transport through atmospheric rivers. through many cycles of discussions, polls, and debates, and was finally Lidya Tarhan works on made official this year. This is not the first time ancient environments, and the department’s name has changed. Yale is one especially how the earliest of the first educational institutions in the country animal life, at and before the to teach the science of the Earth, starting in 1804 time of the Cambrian explo- with a single faculty member, Benjamin Silliman, as sion 540 million years ago, professor of Chemistry and Natural History.
    [Show full text]
  • Phylum Nemertea)
    THE BIOLOGY AND SYSTEMATICS OF A NEW SPECIES OF RIBBON WORM, GENUS TUBULANUS (PHYLUM NEMERTEA) By Rebecca Kirk Ritger Submitted to the Faculty of the College of Arts and Sciences of American University in Partial Fulfillment of the Requirements for the Degree of Master of Science In Biology Chair: Dr. Qiristopher'Tudge m Dr.David C r. Jon L. Norenburg Dean of the College of Arts and Sciences JuK4£ __________ Date 2004 American University Washington, D.C. 20016 AMERICAN UNIVERSITY LIBRARY 1 1 0 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 1421360 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. ® UMI UMI Microform 1421360 Copyright 2004 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. THE BIOLOGY AND SYSTEMATICS OF A NEW SPECIES OF RIBBON WORM, GENUS TUBULANUS (PHYLUM NEMERTEA) By Rebecca Kirk Ritger ABSTRACT Most nemerteans are studied from poorly preserved museum specimens.
    [Show full text]
  • Comparative Neuroanatomy of Mollusks and Nemerteans in the Context of Deep Metazoan Phylogeny
    Comparative Neuroanatomy of Mollusks and Nemerteans in the Context of Deep Metazoan Phylogeny Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der RWTH Aachen University zur Erlangung des akademischen Grades einer Doktorin der Naturwissenschaften genehmigte Dissertation vorgelegt von Diplom-Biologin Simone Faller aus Frankfurt am Main Berichter: Privatdozent Dr. Rudolf Loesel Universitätsprofessor Dr. Peter Bräunig Tag der mündlichen Prüfung: 09. März 2012 Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar. Contents 1 General Introduction 1 Deep Metazoan Phylogeny 1 Neurophylogeny 2 Mollusca 5 Nemertea 6 Aim of the thesis 7 2 Neuroanatomy of Minor Mollusca 9 Introduction 9 Material and Methods 10 Results 12 Caudofoveata 12 Scutopus ventrolineatus 12 Falcidens crossotus 16 Solenogastres 16 Dorymenia sarsii 16 Polyplacophora 20 Lepidochitona cinerea 20 Acanthochitona crinita 20 Scaphopoda 22 Antalis entalis 22 Entalina quinquangularis 24 Discussion 25 Structure of the brain and nerve cords 25 Caudofoveata 25 Solenogastres 26 Polyplacophora 27 Scaphopoda 27 i CONTENTS Evolutionary considerations 28 Relationship among non-conchiferan molluscan taxa 28 Position of the Scaphopoda within Conchifera 29 Position of Mollusca within Protostomia 30 3 Neuroanatomy of Nemertea 33 Introduction 33 Material and Methods 34 Results 35 Brain 35 Cerebral organ 38 Nerve cords and peripheral nervous system 38 Discussion 38 Peripheral nervous system 40 Central nervous system 40 In search for the urbilaterian brain 42 4 General Discussion 45 Evolution of higher brain centers 46 Neuroanatomical glossary and data matrix – Essential steps toward a cladistic analysis of neuroanatomical data 49 5 Summary 53 6 Zusammenfassung 57 7 References 61 Danksagung 75 Lebenslauf 79 ii iii 1 General Introduction Deep Metazoan Phylogeny The concept of phylogeny follows directly from the theory of evolution as published by Charles Darwin in The origin of species (1859).
    [Show full text]
  • Type and Figured Fossils in the Worthen Collection at the Illinois
    s Cq&JI ^XXKUJtJLI 14oGS: CIR 524 c, 2 TYPE AND FIGURED FOSSILS IN THE WORTHEN COLLECTION AT THE ILLINOIS STATE GEOLOGICAL SURVEY Lois S. Kent GEOLOGICAL ILLINOIS Illinois Department of Energy and Natural Resources, STATE GEOLOGICAL SURVEY DIVISION CIRCULAR 524 1982 COVER: This portrait of Amos Henry Worthen is from a print presented to me by Worthen's great-grandson, Arthur C. Brookley, Jr., at the time he visited the Illinois State Geological Survey in the late 1950s or early 1960s. The picture is the same as that published in connection with the memorial to Worthen in the appendix to Vol. 8 of the Geological Survey of Illinois, 1890. -LSK Kent, Lois S., Type and figured fossils in the Worthen Collection at the Illinois State Geological Survey. — Champaign, III. : Illinois State Geological Survey, 1982. - 65 p. ; 28 cm. (Circular / Illinois State Geological Survey ; 524) 1. Paleontology. 2. Catalogs and collections. 3. Worthen Collection. I. Title. II. Series. Editor: Mary Clockner Cover: Sandra Stecyk Printed by the authority of the State of Illinois/1982/2500 II I IHOI'.MAII '.I 'II Of.ir.AI MIHVI y '> 300 1 00003 5216 TYPE AND FIGURED FOSSILS IN THE WORTHEN COLLECTION AT THE ILLINOIS STATE GEOLOGICAL SURVEY Lois S. Kent | CIRCULAR 524 1982 ILLINOIS STATE GEOLOGICAL SURVEY Robert E. Bergstrom, Acting Chief Natural Resources Building, 615 East Peabody Drive, Champaign, IL 61820 TYPE AND FIGURED FOSSILS IN THE WORTHEN COLLECTION AT THE ILLINOIS STATE GEOLOGICAL SURVEY CONTENTS Acknowledgments 2 Introduction 2 Organization of the catalog 7 Notes 8 References 8 Fossil catalog 13 ABSTRACT This catalog lists all type and figured specimens of fossils in the part of the "Worthen Collection" now housed at the Illinois State Geological Survey in Champaign, Illinois.
    [Show full text]
  • MYRIAPODS 767 Volume 2 (M-Z), Pp
    In: R. Singer, (ed.), 1999. Encyclopedia of Paleontology, MYRIAPODS 767 volume 2 (M-Z), pp. 767-775. Fitzroy Dearborn, London. MYRIAPODS JVlyriapods are many-legged, terrestrial arthropods whose bodies groups, the Trilobita, Chelicerata, Crustacea, and the Uniramia, the are divided into two major parts, a head and a trunk. The head last consisting of the Myriapoda, Hexapoda, and Onychophora (vel- bears a single pair of antennae, highly differentiated mandibles (or vet worms). However, subsequent structural and molecular evidence jaws), and at least one pair of maxillary mouthparts; the trunk indicates that there are several characters uniting major arthropod region consists of similar "metameres," each of which is a func- taxa. Moreover, paleobiologic, embryologie, and other evidence tional segment that bears one or two pairs of appendages. Gas demonstrates that myriapods and hexapods are fiindamentally exchange is accomplished by tracheae•a branching network of polyramous, having two major articulating appendages per embry- specialized tubules•although small forms respire through the ological body segment, like other arthropods. body wall. Malpighian organs are used for excretion, and eyes con- A fourth proposal (Figure ID) suggests that myriapods are sist of clusters of simple, unintegrated, light-sensitive elements an ancient, basal arthropod lineage, and that the Hexapoda that are termed ommatidia. These major features collectively char- emerged as an independent, relatively recent clade from a rather acterize the five major myriapod clades: Diplopoda (millipeds), terminal crustacean lineage, perhaps the Malacostraca, which con- Chilopoda (centipeds), Pauropoda (pauropods), Symphyla (sym- tains lobsters and crabs (Ballard et al. 1992). Because few crusta- phylans), and Arthropleurida (arthropleurids). Other features cean taxa were examined in this analysis, and due to the Cambrian indicate differences among these clades.
    [Show full text]
  • A NEW METAZOAN from the MIDDLE CAMBRIAN of UTAH and the NATURE of the VETULICOLIA by DEREK E
    [Palaeontology, Vol. 48, Part 4, 2005, pp. 681–686] RAPID COMMUNICATION A NEW METAZOAN FROM THE MIDDLE CAMBRIAN OF UTAH AND THE NATURE OF THE VETULICOLIA by DEREK E. G. BRIGGS*, BRUCES.LIEBERMAN , SUSAN L. HALGEDAHLà and RICHARD D. JARRARDà *Department of Geology and Geophysics, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA; e-mail: [email protected] Department of Geology, University of Kansas, 1475 Jayhawk Boulevard, 120 Lindley Hall, Lawrence, KS 66045, USA àDepartment of Geology and Geophysics, University of Utah, 135 S. 1460 East, Salt Lake City, UT 84112, USA Typescript received 22 November 2004; accepted in revised form 24 March 2005 Abstract: A new metazoan, Skeemella clavula gen. et sp. arthropodan in character. The similarity of this fossil nov., is described from the Middle Cambrian Pierson Cove to vetulicolians throws hypotheses of their deuterostome Formation of the Drum Mountains, Utah, USA. Skeemella affinity into question and highlights their problematic sta- is similar to vetulicolians, but differs from other examples tus. of this group in the relative proportions of the anterior and posterior sections, the large number of divisions, and Key words: vetulicolian, Cambrian, deuterostome, arthro- the elongate bifid termination. The posterior section is pod. The very name vetulicolian conjures up creatures from species Banffia confusa, to erect a new class of stem-group another planet. These extraordinary fossils, with a head arthropods, the Vetulicolida. They argued that Banffia shield-like anterior and narrow segmented trunk-like pos- constricta from the Burgess Shale belongs to the same terior, are the latest Cambrian group to be accorded phy- class, extending its range to North America.
    [Show full text]
  • Harry Whittington Dies 94
    Published: 5:58PM BST 08 Aug 2010 Professor Harry Whittington Professor Harry Whittington, who died on June 20 aged 94, was the former Woodwardian Professor of Geology at Cambridge and the world’s leading authority on fossil trilobites; in later life he led painstaking research which revealed a “Cambrian explosion” and raised disturbing questions about the proCesses of evolution. Trilobites were hard-carapaced creatures, which thrived, in the Cambrian period, beginning 542 million years ago, until they died out nearly 300 million years later. Very distantly related to horseshoe crabs, they lived in the sea and crawled on land, evolving into more than 20,000 different species, ranging in size from a millimetre to nearly two feet. Many known species are ones which Whittington himself discovered on field trips around the world. Usually it is difficult to extract the fossils from the surrounding rock, but in the 1940s Whittington and his colleague Bill Evitt investigated beds in Virginia where the carapaces of the animals had been replaced by insoluble silica. By throwing samples into acid, they were able to recover thousands of perfect specimens, ranging from fully-grown adults to microscopic larvae. These fossils enabled Whittington, in a series of monographs published in the 1950s and 1960s, to revolutionize what we know about trilobites — how they grew from larva to maturity through successive molts, how they moved and articulated their bodies, and how they evolved and migrated. Later in his career, in 1966, Whittington was invited by the Canadian Geological Society to chair a group commissioned to examine the Burgess Shale deposits discovered by CD Walcott during the building of the Canadian Pacific Railway in 1909.
    [Show full text]
  • Probabilistic Methods Surpass Parsimony When Assessing Clade Support in Phylogenetic Analyses of Discrete Morphological Data
    O'Reilly, J., Puttick, M., Pisani, D., & Donoghue, P. (2017). Probabilistic methods surpass parsimony when assessing clade support in phylogenetic analyses of discrete morphological data. Palaeontology. https://doi.org/10.1111/pala.12330 Publisher's PDF, also known as Version of record License (if available): CC BY Link to published version (if available): 10.1111/pala.12330 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Wiley at http://onlinelibrary.wiley.com/doi/10.1111/pala.12330/abstract. Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ [Palaeontology, 2017, pp. 1–14] PROBABILISTIC METHODS SURPASS PARSIMONY WHEN ASSESSING CLADE SUPPORT IN PHYLOGENETIC ANALYSES OF DISCRETE MORPHOLOGICAL DATA by JOSEPH E. O’REILLY1 ,MARKN.PUTTICK1,2 , DAVIDE PISANI1,3 and PHILIP C. J. DONOGHUE1 1School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, UK; [email protected]; [email protected]; [email protected]; [email protected] 2Department of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK 3School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, UK Typescript received 28 April 2017; accepted in revised form 13 September 2017 Abstract: Fossil taxa are critical to inferences of historical 50% support.
    [Show full text]
  • THE SYNTHETIC THEORY of EVOLUTION DNA Makes RNA, RNA Makes Protein and Proteins Make Us
    320 Chapter f THE AGE OF MAMMALS The Present is the Key to the Past: HUGH RANCE THE SYNTHETIC THEORY OF EVOLUTION DNA makes RNA, RNA makes protein and proteins make us. —Crick.1 f14 Genes, alleles < deoxyribonucleic acid > ...using the metaphor of computation to describe the role of genes is bad biology, for it implies an internal self-sufficiency of DNA. Even if we had the complete DNA sequence of an organism and unlimited computational power, we could not compute an organism, because an organism does not compute itself from its genes. (In fact, any computer that did as poor a job of computation as a genetic “program” does of an organism would immediately be thrown into the trash.) —Richard Lewontin The Triple Helix: Gene, Organism, and Environment, 2000.2 Mathematical population theorists Ronald Aylmer Fisher (The Genetical Theory of Natural Selection, 1930),3 John Burdon Sanderson Haldane (design disparaging: “[He has] an inordinate fondness for beetles.”),4 and Sewall Wright (conceiver of “adaptive landscapes”)5 were the principle forgers, during the period 1920-1950, of the modern theory of population genetics that unites previously warring concepts (Footnote f14.1) of Darwinian natural selection, which is decidedly nonrandom, that guides evolution incrementally (by gradual change) but rapidly by its recursiveness (the output of previous selection is input for subsequent selection), along paths to fitness, and the purely random nature (no inherent directionality, no predictability) of heredity by large sudden changes (saltations, hopeful monsters) that Mendelian rules suggested to some geneticists (principally, typologists William Bateson, Hugo de Vries, and Wilhelm Johannsen).
    [Show full text]