DOCSLIB.ORG

Ontogeny of the Trilobite Redlichia from the Lower Cambrian (Series 2

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ontogeny of the Trilobite Redlichia from the Lower Cambrian (Series 2 Geological Magazine Ontogeny of the trilobite Redlichia from the www.cambridge.org/geo lower Cambrian (Series 2, Stage 4) Ramsay Limestone of South Australia 1 2 3,4 Original Article James D. Holmes , John R. Paterson , James B. Jago and Diego C. García-Bellido1,4 Cite this article: Holmes JD, Paterson JR, Jago JB, and García-Bellido DC (2021) 1School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia; Ontogeny of the trilobite Redlichia from the 2 lower Cambrian (Series 2, Stage 4) Ramsay Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, 3 Limestone of South Australia. Geological Armidale, New South Wales 2351, Australia; University of South Australia, STEM, Mawson Lakes, South 4 Magazine 158: 1209–1223. https://doi.org/ Australia 5095, Australia and South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia 10.1017/S0016756820001259 Abstract Received: 19 March 2020 Revised: 23 September 2020 Studies that reveal detailed information about trilobite growth, particularly early developmental Accepted: 13 October 2020 stages, are crucial for improving our understanding of the phylogenetic relationships within this First published online: 2 December 2020 iconic group of fossil arthropods. Here we document an essentially complete ontogeny of the Keywords: trilobite Redlichia cf. versabunda from the Cambrian Series 2 (late Stage 4) Ramsay Limestone Redlichiida; Redlichiidae; protaspid; meraspid; of Yorke Peninsula in South Australia, including some of the best-preserved protaspides (the arthropod; early Cambrian earliest biomineralized trilobite larval stage) known for any Cambrian trilobite. These protaspid stages exhibit similar morphological characteristics to many other taxa within the Suborder Author for correspondence: James D. Holmes, Email: [email protected] Redlichiina, especially to closely related species such as Metaredlichia cylindrica from the early Cambrian period of China. Morphological patterns observed across early developmental stages of different groups within the Order Redlichiida are discussed. Although redlichiine protaspides exhibit similar overall morphologies, certain ontogenetic characters within this suborder have potential phylogenetic signal, with different superfamilies characterized by unique trait combinations in these early growth stages. 1. Introduction Trilobites are one of the most recognized and well-studied Palaeozoic groups. However, despite over 150 years of research and >22 000 described species, the relationships between higher-level groups within this iconic class of fossil arthropods remain unclear (Adrain, 2011; Paterson, 2020). Advances in our understanding of the ontogeny of different trilobite groups will help to resolve these problems by providing crucial information for phylogenetic analyses (e.g. Edgecombe et al. 1988; Fortey & Chatterton, 1988; Chatterton et al. 1990; Chatterton & Speyer, 1997; Hughes et al. 2017). Determining the relationships between Cambrian trilobites in particular will help to illuminate not only the origins of the class (e.g. by providing informa- tion on character polarities; Paterson et al. 2019), but also assist in resolving how some post- Cambrian clades are related to Cambrian taxa (the so-called ‘cryptogenesis problem’; see Paterson, 2020). Developmental information from early Cambrian trilobites considered to be ‘primitive’, such as those belonging to the Order Redlichiida, is therefore of high importance. Within the Redlichiida (specifically the suborder Redlichiina sensu Adrain, 2011), instances where multiple, well-preserved protaspides (the earliest biomineralized larval stage) are known is limited to less than 10 species. The most informative of these are phosphatized specimens of the estaingiid Ichangia ichangensis Zhang, 1957 and several indeterminate species described by Zhang & Pratt (1999) and Zhang & Clarkson (2012). Protaspides from several other ellipsoce- phaloid species preserved in shale or mudstone are also well known, including the ellipsoce- phalid Ellipsostrenua granulosa (Ahlberg, 1983) (Laibl et al. 2018) and the estaingiid Estaingia sinensis (Zhang, 1953) (Dai & Zhang, 2012a). Early ontogenetic information for the other major redlichiine superfamilies Redlichioidea and Paradoxidoidea is more limited, although Laibl et al.(2017) described ‘giant’ protaspides of two paradoxidid species from the Miaolingian of the Czech Republic, and Dai & Zhang (2012b) presented well-preserved examples of the redlichiid Metaredlichia cylindrica (Zhang, 1953) from Cambrian Stage 3 of Hubei Province, China. Protaspides are either unknown from other examples of redlichiine © The Author(s), 2020. Published by Cambridge ontogenies (e.g. Dai & Zhang, 2013), or represent relatively poorly preserved or isolated University Press. examples that do not provide detailed morphological information of protaspid stages (e.g. Westergård, 1936; Lu, 1940; Kautsky, 1945; Whittington, 1957; Šnajdr, 1958; Pocock, 1970; Öpik, 1975; Zhang et al. 1980; Pillola, 1991; Palmer & Rowell, 1995; Hou et al. 2017). Here we describe a relatively complete post-embryonic ontogenetic series of the trilobite Redlichia cf. versabunda Öpik, 1970 from the Cambrian Series 2 (late Stage 4) Ramsay Downloaded from https://www.cambridge.org/core. University of Athens, on 29 Sep 2021 at 07:47:39, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0016756820001259 1210 JD Holmes et al. Fig. 1. (Colour online) (a) Map of southeastern South Australia showing the location of the Stansbury and Arrowie basins and the study area. (b) Map of central Yorke Peninsula showing the locality within the Ramsay Limestone where material considered in this study was collected (pentagon), as well as the locations of several drill holes that intersect the formation in the vicinity (stars). Limestone of Yorke Peninsula (South Australia), including some of intersected by the Minlaton-1, Minlaton-2 and Cur-D1B drill the best-preserved redlichioid protaspides known to date. holes, with the formation represented in these by dark- to light- grey, mottled, nodular limestones interbedded variously with shales, siltstones, planar stromatolites and evaporites (Ludbrook, 2. Geological setting 1965; Daily, 1990; Gravestock et al. 2001). Redlichia was reported by B Daily (unpub. report, 1957) from the basal c. 25 m of the for- The Ramsay Limestone on Yorke Peninsula, and its temporal equiv- mation in Minlaton-1. The Ramsay Limestone conformably over- alents the Wirrealpa and Aroona Creek limestones (Flinders lies conglomerates, arkoses and evaporites of the Minlaton Ranges), form part of the second major depositional sequence of Formation and conformably underlies the shales, siltstones and the Cambrian succession in the Stansbury and Arrowie basins (as calcareous sandstones of the Corrodgery Formation (Fig. 2) defined by Gravestock, 1995; Gravestock & Shergold, 2001), repre- (Daily, 1990; Gravestock et al. 2001). senting relatively warm, shallow-marine environments during the last major Cambrian transgression in South Australia. These units are considered contemporaneous based on the co-occurrence of 3. Occurrence of Redlichia in the Ramsay and Wirrealpa Daily’s(1956) ‘Faunal Assemblage 10’ (e.g. Horwitz & Daily, limestones 1958; Daily, 1990;Brock&Cooper,1993). The Ramsay Limestone is known from central Yorke Peninsula Trilobites within the upper part of the Cambrian succession in in the Stansbury Basin (Fig. 1a), where it crops out in a small area South Australia (i.e. above the first major depositional sequence c. 7 km south of Curramulka as ‘dark, blue-grey, mottled, argilla- of Gravestock, 1995 and Gravestock & Shergold, 2001) are rare. ceous limestone’ (Daily, 1990, p. 223), as well as in the subsurface Only three instances in three successive formations are currently from a number of drill holes in the general vicinity (Fig. 1b). It has a recognized from the Arrowie Basin in the Flinders Ranges (Jago maximum thickness of 85 m in the Stansbury West-1 well, within et al. 2006, 2020): the emuellid Balcoracania dailyi Pocock, 1970 which Daily (1990) reported shelly fossils (including Redlichia) from the Billy Creek Formation (Paterson & Edgecombe, 2006; from oolitic, sandy and dolomitic limestones c. 15 m below the Paterson et al. 2007); ‘Redlichia guizhouensis’ (re-assigned here top of the formation. The Ramsay Limestone is 68.6 m thick in to R. cf. versabunda) from the Wirrealpa Limestone and equivalent the Stansbury Town-1 well, although only a 3-m-section in the Aroona Creek Limestone (Daily, 1976; Jell in Bengtson et al. 1990; upper part of the formation was cored, consisting of interbedded Jago & Zang, 2006; Paterson & Brock, 2007); and Onaraspis rubra grey, nodular, argillaceous limestone and black, pyritic, micaceous Jell in Bengtson et al. 1990 from the Moodlatana Formation siltstone and/or mudstone containing Redlichia and other shelly (Fig. 2). In the Stansbury Basin on Yorke Peninsula, Redlichia fossils (B Daily, unpub. report, 1968; Daily, 1990; Gravestock has been reported from the Ramsay and Stansbury limestones et al. 2001). Lower portions of the Ramsay Limestone were also (e.g. Öpik, 1970; Daily, 1990), and Pagetia cf. edura has been Downloaded from https://www.cambridge.org/core. University of Athens, on 29 Sep 2021 at 07:47:39, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms.
Load more

Recommended publications
  • Available Generic Names for Trilobites
    AVAILABLE GENERIC NAMES FOR TRILOBITES P.A. JELL AND J.M. ADRAIN Jell, P.A. & Adrain, J.M. 30 8 2002: Available generic names for trilobites. Memoirs of the Queensland Museum 48(2): 331-553. Brisbane. ISSN0079-8835. Aconsolidated list of available generic names introduced since the beginning of the binomial nomenclature system for trilobites is presented for the first time. Each entry is accompanied by the author and date of availability, by the name of the type species, by a lithostratigraphic or biostratigraphic and geographic reference for the type species, by a family assignment and by an age indication of the type species at the Period level (e.g. MCAM, LDEV). A second listing of these names is taxonomically arranged in families with the families listed alphabetically, higher level classification being outside the scope of this work. We also provide a list of names that have apparently been applied to trilobites but which remain nomina nuda within the ICZN definition. Peter A. Jell, Queensland Museum, PO Box 3300, South Brisbane, Queensland 4101, Australia; Jonathan M. Adrain, Department of Geoscience, 121 Trowbridge Hall, Univ- ersity of Iowa, Iowa City, Iowa 52242, USA; 1 August 2002. p Trilobites, generic names, checklist. Trilobite fossils attracted the attention of could find. This list was copied on an early spirit humans in different parts of the world from the stencil machine to some 20 or more trilobite very beginning, probably even prehistoric times. workers around the world, principally those who In the 1700s various European natural historians would author the 1959 Treatise edition. Weller began systematic study of living and fossil also drew on this compilation for his Presidential organisms including trilobites.
    [Show full text]
  • Copertina Guida Ai TRILOBITI V3 Esterno
    Enrico Bonino nato in provincia di Bergamo nel 1966, Enrico si è laureato in Geologia presso il Dipartimento di Scienze della Terra dell'Università di Genova. Attualmente risiede in Belgio dove svolge attività come specialista nel settore dei Sistemi di Informazione Geografica e analisi di immagini digitali. Curatore scientifico del Museo Back to the Past, ha pubblicato numerosi volumi di paleontologia in lingua italiana e inglese, collaborando inoltre all’elaborazione di testi e pubblicazioni scientifiche a livello nazonale e internazionale. Oltre alla passione per questa classe di artropodi, i suoi interessi sono orientati alle forme di vita vissute nel Precambriano, stromatoliti, e fossilizzazioni tipo konservat-lagerstätte. Carlo Kier nato a Milano nel 1961, Carlo si è laureato in Legge, ed è attualmente presidente della catena di alberghi Azul Hotel. Risiede a Cancun, Messico, dove si dedica ad attività legate all'ambiente marino. All'età di 16 anni, ha iniziato una lunga collaborazione con il Museo di Storia Naturale di Milano, ed è a partire dal 1970 che prese inizio la vera passione per i trilobiti, dando avvio a quella che oggi è diventata una delle collezioni paleontologiche più importanti al mondo. La sua instancabile attività di ricerca sul terreno in varie parti del globo e la collaborazione con professionisti del settore, ha permesso la descrizione di nuove specie di trilobiti ed artropodi. Una forte determinazione e la costruzione di un nuovo complesso alberghiero (AZUL Sensatori) hanno infine concretizzzato la realizzazione
    [Show full text]
  • Comprehensive Review of Cambrian Himalayan
    http://www.diva-portal.org Postprint This is the accepted version of a paper published in Papers in Palaeontology. This paper has been peer- reviewed but does not include the final publisher proof-corrections or journal pagination. Citation for the original published paper (version of record): Popov, L E., Holmer, L E., Hughes, N C., Ghobadi Pour, M., Myrow, P M. (2015) Himalayan Cambrian brachiopods. Papers in Palaeontology, 1(4): 345-399 http://dx.doi.org/10.1002/spp2.1017 Access to the published version may require subscription. N.B. When citing this work, cite the original published paper. Permanent link to this version: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-255813 HIMALAYAN CAMBRIAN BRACHIOPODS BY LEONID E. POPOV1, LARS E. HOLMER2, NIGEL C. HUGHES3 MANSOUREH GHOBADI POUR4 AND PAUL M. MYROW5 1Department of Geology, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, United Kingdom, <[email protected]>; 2Institute of Earth Sciences, Palaeobiology, Uppsala University, SE-752 36 Uppsala, Sweden, <[email protected]>; 3Department of Earth Sciences, University of California, Riverside, CA 92521, USA <[email protected]>; 4Department of Geology, Faculty of Sciences, Golestan University, Gorgan, Iran and Department of Geology, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, United Kingdom <[email protected]>; 5 Department of Geology, Colorado College, Colorado Springs, CO 80903, USA <[email protected]> Abstract: A synoptic analysis of previously published material and new finds reveals that Himalayan Cambrian brachiopods can be referred to 18 genera, of which 17 are considered herein. These contain 20 taxa assigned to species, of which five are new: Eohadrotreta haydeni, Aphalotreta khemangarensis, Hadrotreta timchristiorum, Prototreta? sumnaensis and Amictocracens? brocki.
    [Show full text]
  • 001-012 Primeras Páginas
    PUBLICACIONES DEL INSTITUTO GEOLÓGICO Y MINERO DE ESPAÑA Serie: CUADERNOS DEL MUSEO GEOMINERO. Nº 9 ADVANCES IN TRILOBITE RESEARCH ADVANCES IN TRILOBITE RESEARCH IN ADVANCES ADVANCES IN TRILOBITE RESEARCH IN ADVANCES planeta tierra Editors: I. Rábano, R. Gozalo and Ciencias de la Tierra para la Sociedad D. García-Bellido 9 788478 407590 MINISTERIO MINISTERIO DE CIENCIA DE CIENCIA E INNOVACIÓN E INNOVACIÓN ADVANCES IN TRILOBITE RESEARCH Editors: I. Rábano, R. Gozalo and D. García-Bellido Instituto Geológico y Minero de España Madrid, 2008 Serie: CUADERNOS DEL MUSEO GEOMINERO, Nº 9 INTERNATIONAL TRILOBITE CONFERENCE (4. 2008. Toledo) Advances in trilobite research: Fourth International Trilobite Conference, Toledo, June,16-24, 2008 / I. Rábano, R. Gozalo and D. García-Bellido, eds.- Madrid: Instituto Geológico y Minero de España, 2008. 448 pgs; ils; 24 cm .- (Cuadernos del Museo Geominero; 9) ISBN 978-84-7840-759-0 1. Fauna trilobites. 2. Congreso. I. Instituto Geológico y Minero de España, ed. II. Rábano,I., ed. III Gozalo, R., ed. IV. García-Bellido, D., ed. 562 All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system now known or to be invented, without permission in writing from the publisher. References to this volume: It is suggested that either of the following alternatives should be used for future bibliographic references to the whole or part of this volume: Rábano, I., Gozalo, R. and García-Bellido, D. (eds.) 2008. Advances in trilobite research. Cuadernos del Museo Geominero, 9.
    [Show full text]
  • Phylogenetic Analysis of the Olenellina Walcott, 1890 (Trilobita, Cambrian) Bruce S
    2 j&o I J. Paleont., 75(1), 2001, pp. 96-115 Copyright © 2001, The Paleontological Society 0022-3360/01 /0075-96$03.00 PHYLOGENETIC ANALYSIS OF THE OLENELLINA WALCOTT, 1890 (TRILOBITA, CAMBRIAN) BRUCE S. LIEBERMAN Departments of Geology and Ecology and Evolutionary Biology, University of Kansas, Lindley Hall, Lawrence 66045, <[email protected]> ABSTRACT—Phylogenetic analysis was used to evaluate evolutionary relationships within the Cambrian suborder Olenellina Walcott, 1890; special emphasis was placed on those taxa outside of the Olenelloidea. Fifty-seven exoskeletal characters were coded for 24 taxa within the Olenellina and two outgroups referable to the "fallotaspidoid" grade. The Olenelloidea, along with the genus Gabriellus Fritz, 1992, are the sister group of the Judomioidea Repina, 1979. The "Nevadioidea" Hupe, 1953 are a paraphyletic grade group. Four new genera are recognized, Plesionevadia, Cambroinyoella, Callavalonia, and Sdzuyomia, and three new species are described, Nevadia fritzi, Cirquella nelsoni, and Cambroinyoella wallacei. Phylogenetic parsimony analysis is also used to make predictions about the ancestral morphology of the Olenellina. This morphology most resembles the morphology found in Plesionevadia and Pseudoju- domia Egorova in Goryanskii and Egorova, 1964. INTRODUCTION group including the "fallotaspidoids" plus the Redlichiina, and HE ANALYSIS of evolutionary patterns during the Early Cam- potentially all other trilobites. Where the Agnostida fit within this T brian has relevance to paleontologists and evolutionary bi- evolutionary topology depends on whether or not one accepts the ologists for several reasons. Chief among these are expanding our arguments of either Fortey and Whittington (1989), Fortey (1990), knowledge of evolutionary mechanisms and topologies. Regard- and Fortey and Theron (1994) or Ramskold and Edgecombe ing evolutionary mechanisms, because the Cambrian radiation (1991).
    [Show full text]
  • Fossils from South China Redefine the Ancestral Euarthropod Body Plan Cédric Aria1 , Fangchen Zhao1, Han Zeng1, Jin Guo2 and Maoyan Zhu1,3*
    Aria et al. BMC Evolutionary Biology (2020) 20:4 https://doi.org/10.1186/s12862-019-1560-7 RESEARCH ARTICLE Open Access Fossils from South China redefine the ancestral euarthropod body plan Cédric Aria1 , Fangchen Zhao1, Han Zeng1, Jin Guo2 and Maoyan Zhu1,3* Abstract Background: Early Cambrian Lagerstätten from China have greatly enriched our perspective on the early evolution of animals, particularly arthropods. However, recent studies have shown that many of these early fossil arthropods were more derived than previously thought, casting uncertainty on the ancestral euarthropod body plan. In addition, evidence from fossilized neural tissues conflicts with external morphology, in particular regarding the homology of the frontalmost appendage. Results: Here we redescribe the multisegmented megacheirans Fortiforceps and Jianfengia and describe Sklerolibyon maomima gen. et sp. nov., which we place in Jianfengiidae, fam. nov. (in Megacheira, emended). We find that jianfengiids show high morphological diversity among megacheirans, both in trunk ornamentation and head anatomy, which encompasses from 2 to 4 post-frontal appendage pairs. These taxa are also characterized by elongate podomeres likely forming seven-segmented endopods, which were misinterpreted in their original descriptions. Plesiomorphic traits also clarify their connection with more ancestral taxa. The structure and position of the “great appendages” relative to likely sensory antero-medial protrusions, as well as the presence of optic peduncles and sclerites, point to an overall
    [Show full text]
  • United States
    DEPARTMENT OF THE INTERIOR BULLETIN OF THE UNITED STATES ISTo. 146 WASHINGTON GOVERNMENT Pit IN TING OFFICE 189C UNITED STATES GEOLOGICAL SURVEY CHAKLES D. WALCOTT, DI11ECTOK BIBLIOGRAPHY AND INDEX NORTH AMEEICAN GEOLOGY, PALEONTOLOGY, PETEOLOGT, AND MINERALOGY THE YEA.R 1895 FEED BOUGHTON WEEKS WASHINGTON Cr O V E U N M K N T P K 1 N T I N G OFFICE 1890 CONTENTS. Page. Letter of trail smittal...... ....................... .......................... 7 Introduction.............'................................................... 9 List of publications examined............................................... 11 Classified key to tlio index .......................................... ........ 15 Bibliography ............................................................... 21 Index....................................................................... 89 LETTER OF TRANSMITTAL DEPARTMENT OF THE INTEEIOE, UNITED STATES GEOLOGICAL SURVEY, DIVISION OF GEOLOGY, Washington, D. 0., June 23, 1896. SIR: I have the honor to transmit herewith the manuscript of a Bibliography and Index of North American Geology, Paleontology, Petrology, and Mineralogy for the year 1895, and to request that it be published as a bulletin of the Survey. Very respectfully, F. B. WEEKS. Hon. CHARLES D. WALCOTT, Director United States Geological Survey. 1 BIBLIOGRAPHY AND INDEX OF NORTH AMERICAN GEOLOGY, PALEONTOLOGY, PETROLOGY, AND MINER­ ALOGY FOR THE YEAR 1895. By FRED BOUGHTON WEEKS. INTRODUCTION. The present work comprises a record of publications on North Ameri­ can geology, paleontology, petrology, and mineralogy for the year 1895. It is planned on the same lines as the previous bulletins (Nos. 130 and 135), excepting that abstracts appearing in regular periodicals have been omitted in this volume. Bibliography. The bibliography consists of full titles of separate papers, classified by authors, an abbreviated reference to the publica­ tion in which the paper is printed, and a brief summary of the con­ tents, each paper being numbered for index reference.
    [Show full text]
  • Morphological Structure of Head and Comparison Between Agraulos Longicephalus Hicks, 1872 and A
    Morphological structure of head and comparison between Agraulos longicephalus Hicks, 1872 and A. ceticephalus Barrande, 1846, from the Drumian of Spain and Czech Republic. Daniel Eduardo Rojas Ariza Proyecto de Grado para optar por el título de Geocientífico Asesor: Jorge Esteve Serrano Universidad de los Andes Facultad de Ciencias Departamento de Geociencias Bogotá, Colombia – diciembre 2020 Contents 1. Abstract 2. Introduction 2.1. Background 2.2. Ptychopariid morphologic features 3. Objective 3.1. General 3.2. Specifics 4. Study Material and Methodology 4.1. Fossils 4.2. Methodology 5. Results: Visualization of morphological variance 5.1. Regression Analysis 5.1.1. Individual regressions 5.1.1.1. A. longicephalus Hicks, 1872 5.1.1.2. A. ceticephalus Barrande, 1846 5.2. Principal Component Analysis (PCA) 5.3. Discriminant Function Analysis (DFA) 5.4. Procrustes ANOVA 6. Discussion 7. Conclusions 8. Acknowledgments 9. References 1. Abstract Order Ptychopariida has always been a problematic group concerning the taxonomic classification of Cambrian trilobites, and even though the temporality of this group is well known, the relation between this order with others, and, the difficulty for classifying ptychopariids have let to diverse problems in the phylogenetic classification of this, and other primitive orders of trilobites. Agraulos is one of the genera belonging to this order and is a common group of the middle Cambrian, it is a well-known genus inside ptychopariids, therefore, morphological knowledge about this taxon could be helpful to analyze morphological patterns among other species from the genus and even other genera inside the family Agraulidae, and even more, about the superfamily Ellipsocephaloidea.
    [Show full text]
  • The Evolution of Trilobite Body Patterning
    ANRV309-EA35-14 ARI 20 March 2007 15:54 The Evolution of Trilobite Body Patterning Nigel C. Hughes Department of Earth Sciences, University of California, Riverside, California 92521; email: [email protected] Annu. Rev. Earth Planet. Sci. 2007. 35:401–34 Key Words First published online as a Review in Advance on Trilobita, trilobitomorph, segmentation, Cambrian, Ordovician, January 29, 2007 diversification, body plan The Annual Review of Earth and Planetary Sciences is online at earth.annualreviews.org Abstract This article’s doi: The good fossil record of trilobite exoskeletal anatomy and on- 10.1146/annurev.earth.35.031306.140258 togeny, coupled with information on their nonbiomineralized tis- Copyright c 2007 by Annual Reviews. sues, permits analysis of how the trilobite body was organized and All rights reserved developed, and the various evolutionary modifications of such pat- 0084-6597/07/0530-0401$20.00 terning within the group. In several respects trilobite development and form appears comparable with that which may have charac- terized the ancestor of most or all euarthropods, giving studies of trilobite body organization special relevance in the light of recent advances in the understanding of arthropod evolution and devel- opment. The Cambrian diversification of trilobites displayed mod- Annu. Rev. Earth Planet. Sci. 2007.35:401-434. Downloaded from arjournals.annualreviews.org ifications in the patterning of the trunk region comparable with by UNIVERSITY OF CALIFORNIA - RIVERSIDE LIBRARY on 05/02/07. For personal use only. those seen among the closest relatives of Trilobita. In contrast, the Ordovician diversification of trilobites, although contributing greatly to the overall diversity within the clade, did so within a nar- rower range of trunk conditions.
    [Show full text]
  • Smithsonian Miscellaneous Collections
    SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 53, NUMBER 6 CAMBRIAN GEOLOGY AND PALEONTOLOGY No. 6.-0LENELLUS AND OTHER GENERA OF THE MESONACID/E With Twenty-Two Plates CHARLES D. WALCOTT (Publication 1934) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION AUGUST 12, 1910 Zl^i £orb (gaitimovt (pnee BALTIMORE, MD., U. S. A. CAMBRIAN GEOLOGY AND PALEONTOLOGY No. 6.—OLENELLUS AND OTHER GENERA OF THE MESONACID^ By CHARLES D. WALCOTT (With Twenty-Two Plates) CONTENTS PAGE Introduction 233 Future work 234 Acknowledgments 234 Order Opisthoparia Beecher 235 Family Mesonacidas Walcott 236 Observations—Development 236 Cephalon 236 Eye 239 Facial sutures 242 Anterior glabellar lobe 242 Hypostoma 243 Thorax 244 Nevadia stage 244 Mesonacis stage 244 Elliptocephala stage 244 Holmia stage 244 Piedeumias stage 245 Olenellus stage 245 Peachella 245 Olenelloides ; 245 Pygidium 245 Delimitation of genera 246 Nevadia 246 Mesonacis 246 Elliptocephala 247 Callavia 247 Holmia 247 Wanneria 248 P.'edeumias 248 Olenellus 248 Peachella 248 Olenelloides 248 Development of Mesonacidas 249 Mesonacidas and Paradoxinas 250 Stratigraphic position of the genera and species 250 Abrupt appearance of the Mesonacidse 252 Geographic distribution 252 Transition from the Mesonacidse to the Paradoxinse 253 Smithsonian Miscellaneous Collections, Vol. 53, No. 6 232 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 Description of genera and species 256 Nevadia, new genus 256 weeksi, new species 257 Mcsonacis Walcott 261 niickwitzi (Schmidt) 262 torelli (Moberg) 264 vermontana
    [Show full text]
  • Soft Anatomy of the Early Cambrian Arthropod Isoxys Curvirostratus from the Chengjiang Biota of South China with a Discussion on the Origination of Great Appendages
    Soft anatomy of the Early Cambrian arthropod Isoxys curvirostratus from the Chengjiang biota of South China with a discussion on the origination of great appendages DONG−JING FU, XING−LIANG ZHANG, and DE−GAN SHU Fu, D.−J., Zhang, X.−L., and Shu, D.−G. 2011. Soft anatomy of the Early Cambrian arthropod Isoxys curvirostratus from the Chengjiang biota of South China with a discussion on the origination of great appendages. Acta Palaeontologica Polonica 56 (4): 843–852. An updated reconstruction of the body plan, functional morphology and lifestyle of the arthropod Isoxys curvirostratus is proposed, based on new fossil specimens with preserved soft anatomy found in several localities of the Lower Cambrian Chengjiang Lagerstätte. The animal was 2–4 cm long and mostly encased in a single carapace which is folded dorsally without an articulated hinge. The attachment of the body to the exoskeleton was probably cephalic and apparently lacked any well−developed adductor muscle system. Large stalked eyes with the eye sphere consisting of two layers (as corneal and rhabdomeric structures) protrude beyond the anterior margin of the carapace. This feature, together with a pair of frontal appendages with five podomeres that each bear a stout spiny outgrowth, suggests it was raptorial. The following 14 pairs of limbs are biramous and uniform in shape. The slim endopod is composed of more than 7 podomeres without terminal claw and the paddle shaped exopod is fringed with at least 17 imbricated gill lamellae along its posterior margin. The design of exopod in association with the inner vascular (respiratory) surface of the carapace indicates I.
    [Show full text]
  • The Larval Stages of Trilobites
    THE LARVAL STAGES OF TRILOBITES. CHARLES E. BEECHER, New Haven, Conn. [From The American Geologist, Vol. XVI, September, 1895.] 166 The American Geologist. September, 1895 THE LARVAL STAGES OF TRILOBITES. By CHARLES E. BEECHEE, New Haven, Conn. (Plates VIII-X.) CONTENTS. PAGE I. Introduction 166 II. The protaspis 167 III. Review of larval stages of trilobites 170 IV. Analysis of variations in trilobite larvae 177 V. Antiquity of the trilobites 181 "VI. Restoration of the protaspis 182 "VII. The crustacean nauplius 186 VIII. Summary 190 IX. References 191 X Explanation of plates 193 I. INTRODUCTION. It is now generally known that the youngest stages of trilobites found as fossils are minute ovate or discoid bodies, not more than one millimetre in length, in which the head por­ tion greatly predominates. Altogether they present very little likeness to the adult form, to which, however, they are trace­ able through a longer or shorter series of modifications. Since Barrande2 first demonstrated the metamorphoses of trilobites, in 1849, similar observations have been made upon a number of different genera by Ford,22 Walcott,34':*>':t6 Mat­ thew,28- 27' 28 Salter,32 Callaway,11' and the writer.4.5-7 The general facts in the ontogeny have thus become well estab­ lished and the main features of the larval form are fairly well understood. Before the recognition of the progressive transformation undergone by trilobites in their development, it was the cus­ tom to apply a name to each variation in the number of tho­ racic segments and in other features of the test.
    [Show full text]