LATE SILURIAN TRILOBITE PALAEOBIOLOGY AND BIODIVERSITY by ANDREW JAMES STOREY A thesis submitted to the University of Birmingham for the degree of DOCTOR OF PHILOSOPHY School of Geography, Earth and Environmental Sciences University of Birmingham February 2012 University of Birmingham Research Archive e-theses repository This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. ABSTRACT Trilobites from the Ludlow and Přídolí of England and Wales are described. A total of 15 families; 36 genera and 53 species are documented herein, including a new genus and seventeen new species; fourteen of which remain under open nomenclature. Most of the trilobites in the British late Silurian are restricted to the shelf, and predominantly occur in the Elton, Bringewood, Leintwardine, and Whitcliffe groups of Wales and the Welsh Borderland. The Elton to Whitcliffe groups represent a shallowing upwards sequence overall; each is characterised by a distinct lithofacies and fauna. The trilobites and brachiopods of the Coldwell Formation of the Lake District Basin are documented, and are comparable with faunas in the Swedish Colonus Shale and the Mottled Mudstones of North Wales. Ludlow trilobite associations, containing commonly co-occurring trilobite taxa, are defined for each palaeoenvironment. Trilobites in the British Přídolí are too rare and sporadic to systematize them into distinct associations. A preliminary study on the global diversity of Silurian trilobites is presented also. A total of six trilobite bioevents are recognised for the Silurian occurring in the argenteus-leptotheca, sedgwickii, centrifugus- murchisoni, nilssoni, formosus, and bouceki-transgrediens graptolite biozones, characterised by elevated extinction rates. For my late grandmothers, Olive Storey and Irene Robins ACKNOWLEDGEMENTS First of all, I would like to thank my project supervisors Alan Thomas, Phil Lane (Keele University), and James Wheeley for their valuable comments on this manuscript, and their much appreciated support and advice. Special thanks are given to Alan for his patience and the development of my scientific writing and practical skills. I thank Alan and Phil for donating and trusting me with their extensive trilobite collection, for the project would not have been possible without it. James, Phil, Gretchel Coldicott, Steve Jones, Dominique Moran, and Aruna Mistry provided a good deal of support during Alan’s absence; I cannot thank them all enough. Thanks are also given to my Msci project supervisor and tutor, Paul Upchurch (University College London), who is responsible for much of my earlier development and aspirations in paleobiology. This project was funded by a University of Birmingham School Studentship (School of Geography, Earth and Environmental Sciences). An EU Synthesis award allowed type material to be studied at the NRM, Stockholm. SYNTHESYS support made available by the European Community - Research Infrastructure Action under the FP6 Structuring the European Research Area Programme 4676. Visits to the various museums in England and Wales to study figured and unfigured material was subsidized by the Richard Owen Research Fund (Palaeontographical Society). The Phillip Scanlan Travel Fund Award paid for a trip to Spain for the Trilo 08 conference. I thank Mike Bassett (National Museum of Wales) for identifying the poorly preserved brachiopods from the Coldwell Formation. Lennart Jeppsson and Jan Bergström provided much needed advice on the stratigraphy of Gotland and Sweden. Richard Waters provided assistance on the stratigraphy of the Hafod Fawr Formation. Phil Crabb and Phil Hurst photographed several figured specimens at the NHM (Natural History Museum). Claire Mellish (NHM), Robert Owens (National Museum of Wales, Cardiff), Derek Siveter and Eliza Howlett (Oxford University Museum), Daniel Lockett (Ludlow Museum), Per Ahlberg (Lund University), Matthew Riley (Sedgwick Museum, Cambridge) provided access to material. Thanks are given to Christine Fransen and all at the NRM, Stockholm for help accessing their collections, and for being such good hosts during my time in Sweden. Paul Shepherd helped locate specimens housed at the British Geological Survey (Keyworth), and John Clatworthy (University of Birmingham) helped organize figured and cited material. Isabel Rábano (Museo Geominero, Madrid) and the Palaeontological Association for granting permission to use previously published figures to produce respectively Text-Figures 2.1 and 2.2, and Text-Figure 2.5. Special thanks are given to Helen Hughes who helped me settle into my PhD, and for the many helpful trilobite related discussions. To everyone in 113, in particular Sarah King, Andy Rees, Leyla Seyfullah, Ben Slater, and Lil Stephens. To my brother and sister- in-law, Richard and Hannah, for their much need support. I would also like to thank Richard for helping print my thesis. Finally to my parents, Raymond and Carolyn, who I am sure, have heard quite enough about trilobites. ‘I have nothing to offer but blood, toil, tears, and sweat. We have before us an ordeal of the most grievous kind. We have before us many, many long months of struggle and of suffering. You ask, what is our aim? I can answer in one word: Victory. Victory at all costs – Victory in spite of all terror – Victory, however long and hard the road may be.’ Winston Churchill, 13 May 1940. TABLE OF CONTENTS CHAPTER ONE: INTRODUCTION 1 1.1 BACKGROUND: THE BRITISH SILURIAN AND 1 TRILOBITE SYSTEMATICS 1.2 GEOLOGICAL AND PALAEOENVIRONMENTAL 3 CONTEXT 1.3 PROJECT AIMS 4 CHAPTER TWO: A DEEP-WATER ASSOCIATION FROM THE 7 LATE WENLOCK\EARLY LUDLOW OF THE ENGLISH LAKE DISTRICT 2.1 INTRODUCTION 7 2.2 GEOLOGICAL AND STRATIGRAPHICAL SETTING 9 2.3 THE COLDWELL FORMATION: TRILOBITE FAUNA 15 2.4 SYSTEMATIC PALAEONTOLOGY 17 2.4.1 Material and Methods 17 2.4.2 Trilobite classification: genera/subgenera and 19 species/subspecies 2.4.3 Genus BARRIEPSICATOR gen. nov. 22 Barriepsicator mobergi (Hede, 1915) 24 Barriepsicator noblilis (Thomas, 1900) 27 2.4.4 Genus DELOPS Rickards, 1965 29 Delops obtusicaudatus (Salter, 1865) 32 2.4.5 Genus STRUVERIA Rickards, 1965 35 Struveria simrica (Hede, 1915) 36 2.4.6 Genus CALYMENE Brongniart, 1822 39 Calymene sp. 39 2.4.7 Subfamily CHEIRURINAE Salter, 1864 40 Ktenoura postrema (Lane, 1971) 40 Cheirurinae indet. 42 2.4.8 Genus SPHAEROCORYPHE Angelin, 1854 42 Sphaerocoryphe sp. 43 2.4.9 Family ENCRINURIDAE Angelin, 1854 43 ?Encrinuridae indet. 43 2.4.10 Genus DECOROPROETUS Přibyl, 1946 44 Decoroproetus scrobiculatus scrobiculatus Owens, 1973 44 Decoroproetus sp. nov? 47 2.4.11 Genus MIRASPIS Richter and Richter, 1917 49 Miraspis sp. 49 2.4.12 Family HARPETIDAE Hawle and Corda, 1847 50 Harpetidae indet. 50 2.5 CLADISTIC ANALYSIS OF SILURIAN DALMANITIDS 51 2.5.1 Method 52 2.5.2 Results 57 2.6 THE COLDWELL FORMATION: SHELLY FAUNA 60 2.7 THE COLDWELL FORMATION: PALAEOENVIRONMENT 61 2.8 COMPARISON WITH OTHER TRILOBITE FAUNAS 62 CHAPTER THREE: TRILOBITE ASSOCIATIONS FROM THE 80 LATE SILURIAN SHELF SEQUENCES OF ENGLAND AND WALES 3.1 INTRODUCTION 80 3.2 GEOLOGICAL AND PALAEOENVIRONMENTAL SETTING 82 3.3 STRATIGRAPHICAL SETTING 86 3.4 SYSTEMATIC PALAEONTOLOGY 94 3.4.1 Material, Localities, and Methods 94 3.4.2 Family SCUTELLUIDAE Richter and Richter, 1955 103 Genus KOSOVOPELTIS Šnajdr, 1958 103 Kosovopeltis? signata (Phillips, 1841) 103 Kosovopeltis? sp. 104 Scutelluidae indet. 105 3.4.3 Family LICHIDAE Hawle and Corda, 1847 105 Genus DICRANOPELTIS Hawle and Corda, 1847 105 Dicranopeltis salteri (Fletcher, 1850) 105 Genus RICHTERARGES Phleger, 1936 107 Richterarges bucklandii (Milne Edwards, 1840) 107 Genus PLATYLICHAS Gűrich, 1901 109 Platylichas (Rontrippa) grayii (Fletcher, 1850 109 3.4.4 Family ODONTOPLEURIDAE Burmeister, 1843 110 Genus ACIDSDPIS Murchison, 1839 110 Acidaspis brightii Murchison, 1839 111 Genus EXALLASPIS Ramsköld and Chatterton, 1991 112 Exallaspis coronata (Salter, 1853) 113 Genus ODONTOPLEURA Emmrich, 1839 117 Odontopleura ovata Emmrich, 1839 118 3.4.5 Family HOMALONOTIDAE Chapman, 1890 119 Genus HOMALONOTUS König, 1825 119 Homalonotus knightii König, 1825 119 Genus TRIMERUS Green, 1832 123 Trimerus (Trimerus) johannis (Salter, 1865) 124 Trimerus (?Ramiotis) salteri (Morris, 1988) 127 3.4.6 Family CALYMENIDAE Burmeister, 1843 129 Genus CALYMENE Brongniart, 1822 129 Calymene oliveae sp. nov. 131 Genus ALCYMENE Ramsköld et al., 1994 133 Alcymene neointermedia (Richter and Richter, 1954) 135 Alcymene lawsoni (Shirley, 1962) 137 Alcymene cf. lawsoni (Shirley, 1962) 139 Alcymene (s.l.) aff. A. lawsoni (Shirley, 1962) 139 Alcymene puellaris (Reed, 1920) 141 Alcymene cf. puellaris (Reed, 1920) 145 Genus DIACALYMENE Kegel, 1927 145 Diacalymene? sp. 145 3.4.7 Family DALMANITIDAE Vogdes, 1890 146 Genus DALMANITES Barrande, 1852 146 Dalmanites myops (König, 1825) 152 Dalmanites nexilis (Salter, 1864) 154 Dalmanites aff. nexilis (Salter, 1864) 157 Dalmanites obtusus (Lindström, 1885) 158 Dalmanites tuberculatocaudatus (Murchison, 1839) 161 Discussion 164 3.4.8 Family ACASTIDAE Delo, 1935 165 Genus ACASTE Goldfuss, 1843 165