The Significance of Moulting in Ecdysozoan Evolution
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Platyhelminthes, Nemertea, and "Aschelminthes" - A
BIOLOGICAL SCIENCE FUNDAMENTALS AND SYSTEMATICS – Vol. III - Platyhelminthes, Nemertea, and "Aschelminthes" - A. Schmidt-Rhaesa PLATYHELMINTHES, NEMERTEA, AND “ASCHELMINTHES” A. Schmidt-Rhaesa University of Bielefeld, Germany Keywords: Platyhelminthes, Nemertea, Gnathifera, Gnathostomulida, Micrognathozoa, Rotifera, Acanthocephala, Cycliophora, Nemathelminthes, Gastrotricha, Nematoda, Nematomorpha, Priapulida, Kinorhyncha, Loricifera Contents 1. Introduction 2. General Morphology 3. Platyhelminthes, the Flatworms 4. Nemertea (Nemertini), the Ribbon Worms 5. “Aschelminthes” 5.1. Gnathifera 5.1.1. Gnathostomulida 5.1.2. Micrognathozoa (Limnognathia maerski) 5.1.3. Rotifera 5.1.4. Acanthocephala 5.1.5. Cycliophora (Symbion pandora) 5.2. Nemathelminthes 5.2.1. Gastrotricha 5.2.2. Nematoda, the Roundworms 5.2.3. Nematomorpha, the Horsehair Worms 5.2.4. Priapulida 5.2.5. Kinorhyncha 5.2.6. Loricifera Acknowledgements Glossary Bibliography Biographical Sketch Summary UNESCO – EOLSS This chapter provides information on several basal bilaterian groups: flatworms, nemerteans, Gnathifera,SAMPLE and Nemathelminthes. CHAPTERS These include species-rich taxa such as Nematoda and Platyhelminthes, and as taxa with few or even only one species, such as Micrognathozoa (Limnognathia maerski) and Cycliophora (Symbion pandora). All Acanthocephala and subgroups of Platyhelminthes and Nematoda, are parasites that often exhibit complex life cycles. Most of the taxa described are marine, but some have also invaded freshwater or the terrestrial environment. “Aschelminthes” are not a natural group, instead, two taxa have been recognized that were earlier summarized under this name. Gnathifera include taxa with a conspicuous jaw apparatus such as Gnathostomulida, Micrognathozoa, and Rotifera. Although they do not possess a jaw apparatus, Acanthocephala also belong to Gnathifera due to their epidermal structure. ©Encyclopedia of Life Support Systems (EOLSS) BIOLOGICAL SCIENCE FUNDAMENTALS AND SYSTEMATICS – Vol. -
Defining Phyla: Evolutionary Pathways to Metazoan Body Plans
EVOLUTION & DEVELOPMENT 3:6, 432-442 (2001) Defining phyla: evolutionary pathways to metazoan body plans Allen G. Collins^ and James W. Valentine* Museum of Paleontology and Department of Integrative Biology, University of California, Berkeley, CA 94720, USA 'Author for correspondence (email: [email protected]) 'Present address: Section of Ecology, Befiavior, and Evolution, Division of Biology, University of California, San Diego, La Jolla, CA 92093-0116, USA SUMMARY Phyla are defined by two sets of criteria, one pothesis of Nielsen; the clonal hypothesis of Dewel; the set- morphological and the other historical. Molecular evidence aside cell hypothesis of Davidson et al.; and a benthic hy- permits the grouping of animals into clades and suggests that pothesis suggested by the fossil record. It is concluded that a some groups widely recognized as phyla are paraphyletic, benthic radiation of animals could have supplied the ances- while some may be polyphyletic; the phyletic status of crown tral lineages of all but a few phyla, is consistent with molecu- phyla is tabulated. Four recent evolutionary scenarios for the lar evidence, accords well with fossil evidence, and accounts origins of metazoan phyla and of supraphyletic clades are as- for some of the difficulties in phylogenetic analyses of phyla sessed in the light of a molecular phylogeny: the trochaea hy- based on morphological criteria. INTRODUCTION Molecules have provided an important operational ad- vance to addressing questions about the origins of animal Concepts of animal phyla have changed importantly from phyla. Molecular developmental and comparative genomic their origins in the six Linnaean classis and four Cuvieran evidence offer insights into the genetic bases of body plan embranchements. -
Radial Symmetry Or Bilateral Symmetry Or "Spherical Symmetry"
Symmetry in biology is the balanced distribution of duplicate body parts or shapes. The body plans of most multicellular organisms exhibit some form of symmetry, either radial symmetry or bilateral symmetry or "spherical symmetry". A small minority exhibit no symmetry (are asymmetric). In nature and biology, symmetry is approximate. For example, plant leaves, while considered symmetric, will rarely match up exactly when folded in half. Radial symmetry These organisms resemble a pie where several cutting planes produce roughly identical pieces. An organism with radial symmetry exhibits no left or right sides. They have a top and a bottom (dorsal and ventral surface) only. Animals Symmetry is important in the taxonomy of animals; animals with bilateral symmetry are classified in the taxon Bilateria, which is generally accepted to be a clade of the kingdom Animalia. Bilateral symmetry means capable of being split into two equal parts so that one part is a mirror image of the other. The line of symmetry lies dorso-ventrally and anterior-posteriorly. Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, which contains the mouth, to the center of the opposite, or aboral, end. This type of symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as sea stars (see special forms of radial symmetry). Animals in the phyla cnidaria and echinodermata exhibit radial symmetry (although many sea anemones and some corals exhibit bilateral symmetry defined by a single structure, the siphonoglyph) (see Willmer, 1990). -
Animal Phylogeny and the Ancestry of Bilaterians: Inferences from Morphology and 18S Rdna Gene Sequences
EVOLUTION & DEVELOPMENT 3:3, 170–205 (2001) Animal phylogeny and the ancestry of bilaterians: inferences from morphology and 18S rDNA gene sequences Kevin J. Peterson and Douglas J. Eernisse* Department of Biological Sciences, Dartmouth College, Hanover NH 03755, USA; and *Department of Biological Science, California State University, Fullerton CA 92834-6850, USA *Author for correspondence (email: [email protected]) SUMMARY Insight into the origin and early evolution of the and protostomes, with ctenophores the bilaterian sister- animal phyla requires an understanding of how animal group, whereas 18S rDNA suggests that the root is within the groups are related to one another. Thus, we set out to explore Lophotrochozoa with acoel flatworms and gnathostomulids animal phylogeny by analyzing with maximum parsimony 138 as basal bilaterians, and with cnidarians the bilaterian sister- morphological characters from 40 metazoan groups, and 304 group. We suggest that this basal position of acoels and gna- 18S rDNA sequences, both separately and together. Both thostomulids is artifactal because for 1000 replicate phyloge- types of data agree that arthropods are not closely related to netic analyses with one random sequence as outgroup, the annelids: the former group with nematodes and other molting majority root with an acoel flatworm or gnathostomulid as the animals (Ecdysozoa), and the latter group with molluscs and basal ingroup lineage. When these problematic taxa are elim- other taxa with spiral cleavage. Furthermore, neither brachi- inated from the matrix, the combined analysis suggests that opods nor chaetognaths group with deuterostomes; brachiopods the root lies between the deuterostomes and protostomes, are allied with the molluscs and annelids (Lophotrochozoa), and Ctenophora is the bilaterian sister-group. -
EST Based Phylogenomics of Syndermata Questions Monophyly
BMC Evolutionary Biology BioMed Central Research article Open Access EST based phylogenomics of Syndermata questions monophyly of Eurotatoria Alexander Witek†1, Holger Herlyn†2, Achim Meyer3, Louis Boell4, Gregor Bucher4 and Thomas Hankeln*1 Address: 1Institute of Molecular Genetics, Johannes Gutenberg-University Mainz, J. J.-Becherweg 32, D-55099 Mainz, Germany, 2Institute of Anthropology, Johannes Gutenberg-University Mainz, Colonel-Kleinmann-Weg 2, D-55099 Mainz, Germany, 3Institute of Zoology, Johannes Gutenberg-University Mainz, Müllerweg 6, D-55099 Mainz, Germany and 4Johann Friedrich Blumenbach Institute of Anthropology and Zoology, Georg-August-University Göttingen, J. v. Liebig-Weg 11, D-37077 Göttingen, Germany Email: Alexander Witek - [email protected]; Holger Herlyn - [email protected]; Achim Meyer - [email protected]; Louis Boell - [email protected]; Gregor Bucher - [email protected]; Thomas Hankeln* - [email protected] * Corresponding author †Equal contributors Published: 29 December 2008 Received: 16 June 2008 Accepted: 29 December 2008 BMC Evolutionary Biology 2008, 8:345 doi:10.1186/1471-2148-8-345 This article is available from: http://www.biomedcentral.com/1471-2148/8/345 © 2008 Witek et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: The metazoan taxon Syndermata comprising Rotifera (in the classical sense of Monogononta+Bdelloidea+Seisonidea) and Acanthocephala has raised several hypotheses connected to the phylogeny of these animal groups and the included subtaxa. -
KEYS to MARINE INVERTEBRATES of the WOODS HOLE REGION
AALPH I SMITH- FDITQP Spe FOR REFERENCE Do Not Take From This Room Ql 573 .3 o- KEYS TO MARINE INVERTEBRATES of the WOODS HOLE REGION A manual for the identification of the more common marine invertebrates, compiled by Ralph I. Smith with the assistance of many other contributors m lor X. ; ru 5: j o " o CD- S' i a z nn § a Contribution No. 11 LL Systematics-Ecology Program, Marine Biological Laboratory Woods Hole, Massachusetts 1964 J CO Copyright 1964 by the Marine Biological Laboratory Tenth Edition Referrals To Marine Biological Laboratory Supply Dept. Woods Hole, Massachusetts 02543 Printed by Spaulding Co., Inc., 29 Pacella Park Drive, Randolph, Mass. 02368 Ill TABLE OF CONTENTS Page List of Plates v Foreword vi Editor's Preface vii Chapter I . Phylum PORIFERA 1 Glossary 1 Key 2 Checklist 6 II. Phylum CNIDARIA, Class Hydrozoa 8 Glossary 8 Key 10 Checklist 17 III. Phylum CNIDARIA, Class Scyphozoa 21 Key to attached Scyphozoa 21 Key to Scyphomedusae 21 IV. Phylum CNIDARIA, Class Anthozoa 25 Key 26 Checklist 26 V. Phylum CTENOPHORA, key and checklist 29 VI . Phylum PLATYHELMINTHES 30 Key to common Turbellarians 30 Checklist of Acoela, Rhabdocoela, and Alloeocoela 32 Checklist of Tricladida 36 Key to Polycladida 36 Checklist of Polycladida 37 VII. Phylum NEMERTEA (RHYNCHOCOELA) 40 Key 40 Checklist 43 VIII. Other Unsegmented Worms: Phylum ASCHELMINTHES 46 Phylum SIPUNCULOIDEA 46 IX. Phylum ANNELIDA 47 Classes Hirudinea, Oligochaeta, and Archiannelida 47 Polychaete Terminology 48 Key to Polychaete Families 51 Keys and checklists of Polychaete Species 63 X. Phylum ARTHROPODA, Subphylum Chelicerata 84 Xiphosurida 84 Key to Pycnogonida 84 Checklist of Pycnogonida 85 XI. -
Irish Biodiversity: a Taxonomic Inventory of Fauna
Irish Biodiversity: a taxonomic inventory of fauna Irish Wildlife Manual No. 38 Irish Biodiversity: a taxonomic inventory of fauna S. E. Ferriss, K. G. Smith, and T. P. Inskipp (editors) Citations: Ferriss, S. E., Smith K. G., & Inskipp T. P. (eds.) Irish Biodiversity: a taxonomic inventory of fauna. Irish Wildlife Manuals, No. 38. National Parks and Wildlife Service, Department of Environment, Heritage and Local Government, Dublin, Ireland. Section author (2009) Section title . In: Ferriss, S. E., Smith K. G., & Inskipp T. P. (eds.) Irish Biodiversity: a taxonomic inventory of fauna. Irish Wildlife Manuals, No. 38. National Parks and Wildlife Service, Department of Environment, Heritage and Local Government, Dublin, Ireland. Cover photos: © Kevin G. Smith and Sarah E. Ferriss Irish Wildlife Manuals Series Editors: N. Kingston and F. Marnell © National Parks and Wildlife Service 2009 ISSN 1393 - 6670 Inventory of Irish fauna ____________________ TABLE OF CONTENTS Executive Summary.............................................................................................................................................1 Acknowledgements.............................................................................................................................................2 Introduction ..........................................................................................................................................................3 Methodology........................................................................................................................................................................3 -
FGF Signaling Induces Mesoderm in Members of Spiralia
bioRxiv preprint doi: https://doi.org/10.1101/2020.08.13.249714; this version posted August 13, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. FGF signaling induces mesoderm in members of Spiralia Carmen Andrikou*1,2 and Andreas Hejnol1,2 1University of Bergen, Department of Biological Sciences, Thormøhlensgate 55, 5006 Bergen, Norway 2Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5006 Bergen, Norway *Corresponding author: [email protected] Abstract FGF signaling is involved in mesoderm induction in deuterostomes, but not in flies and nematodes, where it has a role in mesoderm patterning and migration. However, comparable studies in other protostomic taxa are missing in order to decipher whether this mesoderm-inducing function of FGF extends beyond the lineage of deuterostomes. Here, we investigated the role of FGF signaling during mesoderm development in three species of lophophorates, a clade within the protostome group Spiralia. Our gene expression analyses show that the molecular patterning of mesoderm development is overall conserved between brachiopods and phoronids, but the spatial and temporal recruitment of transcription factors differs significantly. Moreover, inhibitor experiments demonstrate that FGF signaling is involved in mesoderm formation, morphogenetic movements of gastrulation and posterior axial elongation. Our findings suggest that the inductive role of FGF in mesoderm possibly predates the origin of deuterostomes. Keywords: phoronid, brachiopod, development, axial elongation, gastrulation, SU5402, fibroblast growth factor 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.08.13.249714; this version posted August 13, 2020. -
Higher-Level Metazoan Relationships: Recent Progress and Remaining Questions
Org Divers Evol DOI 10.1007/s13127-011-0044-4 REVIEW Higher-level metazoan relationships: recent progress and remaining questions Gregory D. Edgecombe & Gonzalo Giribet & Casey W. Dunn & Andreas Hejnol & Reinhardt M. Kristensen & Ricardo C. Neves & Greg W. Rouse & Katrine Worsaae & Martin V. Sørensen Received: 22 October 2010 /Accepted: 1 March 2011 # Gesellschaft für Biologische Systematik 2011 Abstract Metazoa comprises 35–40 phyla that include Protostomia and Deuterostomia) or membership in Deuter- some 1.3 million described species. Phylogenetic analyses ostomia. The main clades of deuterostomes (Ambulacraria of metazoan interrelationships have progressed in the past and Chordata) and protostomes (Ecdysozoa and Spiralia) two decades from those based on morphology and/or are recovered in numerous analyses based on varied targeted-gene approaches using single and then multiple molecular samples, and also receive anatomical and loci to the more recent phylogenomic approaches that use developmental support. Outstanding issues in protostome hundreds or thousands of genes from genome and tran- phylogenetics are the position of Chaetognatha within the scriptome sequencing projects. A stable core of the tree for protostome clade, and the monophyly of a group of bilaterian animals is now at hand, and instability and spiralians collectively named Platyzoa. In contrast to the conflict are becoming restricted to a key set of important broad consensus over key questions in bilaterian phylog- but contentious relationships. Acoelomorph flatworms eny, the relationships of the five main metazoan lineages— (Acoela + Nemertodermatida) and Xenoturbella are sister Porifera, Ctenophora, Placozoa, Cnidaria and Bilateria— groups. The position of this clade remains controversial, remain subject to conflicting topologies according to with different analyses supporting either a sister-group different taxonomic samples and analytical approaches. -
A Survey of the Marine Nematodes of Chesapeake Bay, Maryland
State of Maryland BOARD OF NATURAL RESOURCES DEPARTMENT OF RESEARCH AND EDUCATION A Survey of The Marine Nematodes of Chesapeake Bay, Maryland December, 1952 Publication No. 95 Chesapeake Biological Laboratory Solomons Island, Maryland COMMISSIONERS Earle T. Hawkins, Chairman ..............................................................................Towson Ernest N. Cory ....................................................................................... Colege Park 33. H. Willier ................................................................................................... .Baltimore Frederick Tresselt .......................................................................................... .Thurmont DIRECTOR R. V. Truitt ............................................................................................Solomons Island STATE WEATHER SERVICE G. N. Brancato, Meteorologist in Charge ......................................................Baltimore CHESAPEAKE BIOLOGICAL LABORATORY Byron L. Ashbaugh, M.Ed., Education Assistant G. F. Beaven, M.A., Biologist I, Oyster Investigations David G. Cargo, M.S., Biologist 11, Crab Investigations Harold J. Elser, Ph.M., Biologist II, Aquatic Investigations Adaline Gall, Secretary George B. Gray, B.S., Administrative Assistant Harry A. Hensel, Jr., Investigator Leah Belle Jones, Senior Stenographer John R. Longwell, M.S., Biologist 111, Game Investigations Joseph H. Manning, M.S., Biologist II, Oyster Investigations Romeo Mansueti, M.S., Biologist 11, Fishery Investigations Harvey -
CPY Document
~ =l~ t f"-'" Molecular Phylogenetics of the Metazoan Clade Lophotrochozoa t:i~ 2ærs By Yale J. Passamaneck B.A., University of California, Santa Cruz, 1996 Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the ~ MASSACHUSETTS INSTITUTE OF TECHNOLOGY li and the lMMTOII WOODS HOLE OCEANOGRAHIC INSTITUTION LIB RARY September 2003 _ HOLE, MASS. W. H. O. L ~ 2003 Woods Hole Oceanographic Institution. All rights reserved. The author hereby grants to MIT and WHOI permission to reproduce paper and electronic copies ofthis thesis document in whole or in part and to distribute them publicly. Signature of Author Joint Program in Biological Oceanography Massachusetts Institute of Technology and Woods Hole Oceanographic Institution September 2003 Certified by . alanych, PhD. Thesis Supervisor Accepted by John Waterbury, Ph.D. Chair, Joint Program for Biological Oceanography Massachusetts Institute of Technology and Woods Hole Oceanographic Institution _ '. '(;J~ ;¡1'~1l'A......,....,..._.u.;i''''''''i#.'',"~''''!:'¡ 'jrl~~'l~~ I 11~(\rrMr~J~~,~..~ ì 1 "-'1tl " /'" ,," n ~ 1... Ñ l .¿· l.¡: l. .líQlj ~~' J .0 .r.~ .W 1 _--~' Molecular Phylogenetics of the Metazoan Clade Lophotrochozoa By Yale 1. Passamaneck Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY and the WOODS HOLE OCEANOGRAHIC INSTITUTION September 2003 ABSTRACT DNA sequencing and phylogenetic analyses were conducted to investigate evolutionary relationships between taxa within the metazoan clade Lophotrochozoa. Chapter i presents an introduction to phylogenetics of the Metazoa and the clade Lophotrochozoa. Chapter 2 analyzes higher level relationships between the major groups within the phylum Mollusca using sequences of the nuclear ribosomal large-subunit RNA gene (LSD rDNA). -
Animal Phylogeny and Its Evolutionary Implications∗
ES45CH17-Dunn ARI 28 October 2014 12:59 Animal Phylogeny and Its Evolutionary Implications∗ Casey W. Dunn,1 Gonzalo Giribet,2 Gregory D. Edgecombe,3 and Andreas Hejnol4 1Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912; email: [email protected] 2Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138; email: [email protected] 3Department of Earth Sciences, The Natural History Museum, London SW7 5BD, United Kingdom; email: [email protected] 4Sars International Centre for Marine Molecular Biology, University of Bergen, 5008 Bergen, Norway; email: [email protected] Annu. Rev. Ecol. Evol. Syst. 2014. 45:371–95 Keywords First published online as a Review in Advance on Metazoa, morphology, evolutionary developmental biology, fossils, September 29, 2014 anatomy The Annual Review of Ecology, Evolution, and Systematics is online at ecolsys.annualreviews.org Abstract This article’s doi: In recent years, scientists have made remarkable progress reconstructing the 10.1146/annurev-ecolsys-120213-091627 animal phylogeny. There is broad agreement regarding many deep animal Copyright c 2014 by Annual Reviews. Access provided by University of Bergen on 11/24/14. For personal use only. relationships, including the monophyly of animals, Bilateria, Protostomia, All rights reserved Ecdysozoa, and Spiralia. This stability now allows researchers to articulate ∗ Annu. Rev. Ecol. Evol. Syst. 2014.45:371-395. Downloaded from www.annualreviews.org This paper was authored by an employee of the the diminishing number of remaining questions in terms of well-defined al- British Government as part of his official duties and is therefore subject to Crown Copyright.