Phylogenetic Affinities of the Enigmatic Protist Nephromyces

Total Page：16

File Type：pdf, Size：1020Kb

Phylogenetic affinities of the enigmatic protist Nephromyces Developing an integrated approach for phylogenetic analysis of a complex tripartite marine symbiosis ©Mary Beth Saffo 2004 How can phylogenetic studies provide insights into the ecological and physiological dynamics of symbiotic interactions? How can understanding of host- symbiont dynamics provide insights into the evolutionary history of the host and microbial taxa? How can Nephromyces enhance understanding of protist phylogeny ? ©Mary Beth Saffo 2004 Molgula occidentalis ©Mary Beth Saffo 2004 Molgula manhattensis ©Mary Beth Saffo 2004 Molgula manhattensis. and company Molgulid host Nephromyces bacteria ©Mary Beth Saffo 2004 Nephromyces Eclectic cells in search of a relative “a fungus with no relatives, not even close ones. .” Paul Buchner ©Mary Beth Saffo 2004 A fungal lifestyle: but is it a fungus?(or even a chytrid?) ©Mary Beth Saffo 2004 ©Mary Beth Saffo 2004 ©Mary Beth Saffo 2004 Thraustochytrium Nephromyces ©Mary Beth Saffo 2004 renal sac new host reproductive vegetative stages stages Nephromyces :life cycle ©Mary Beth Saffo 2004 ssu rDNA: Nephromyces is an apicomplexan Phylogenetic analyses, still in progress, consistently indicate that Nephromyces is a distinct clade within the Apicomplexa. Although the relationship of Nephromyces to other apicomplexans is not yet definitively resolved, in (unweighted) analyses of ssu rDNA sequences thus far, Nephromyces usually groups with non-coccidian clades. (preliminary phylogenetic analysis: a sample maximum likelihood tree) ©Mary Beth Saffo 2004 Apicomplexa •parasites & pathogens • apical complex • apicoplast (remnant algal chloroplast?) Are these features also found in Nephromyces? ©Mary Beth Saffo 2004 24 hours: renal sac 12 hours: Molgula blood ©Mary Beth Saffo 2004 ©Mary Beth Saffo 2004 Vieira et al, Mem. Inst. Oswaldo Cruz (Brazil) 1997 Inside Nephromyces ©Mary Beth Saffo 2004 Symbiotic partners can be highly modified in structure and physiology compared to free-living relatives Molgulids and Nephromyces are distinctive clades: in what ways might their interdependence have affected their respective evolutionary paths, compared to sister taxa? ©Mary Beth Saffo 2004.

Copy Link

Recommended publications

TEXT-BOOKS of ANIMAL BIOLOGY a General Zoology of The
TEXT-BOOKS OF ANIMAL BIOLOGY * Edited by JULIAN S. HUXLEY, F.R.S. A General Zoology of the Invertebrates by G. S. Carter Vertebrate Zoology by G. R. de Beer Comparative Physiology by L. T. Hogben Animal Ecology by Challes Elton Life in Inland Waters by Kathleen Carpenter The Development of Sex in Vertebrates by F. W. Rogers Brambell * Edited by H. MUNRO Fox, F.R.S. Animal Evolution / by G. S. Carter Zoogeography of the Land and Inland Waters by L. F. de Beaufort Parasitism and Symbiosis by M. Caullery PARASITISM AND ~SYMBIOSIS BY MAURICE CAULLERY Translated by Averil M. Lysaght, M.Sc., Ph.D. SIDGWICK AND JACKSON LIMITED LONDON First Published 1952 !.lADE AND PRINTED IN GREAT BRITAIN BY WILLIAM CLOWES AND SONS, LlMITED, LONDON AND BECCLES CONTENTS LIST OF ILLUSTRATIONS vii PREFACE TO THE ENGLISH EDITION xi CHAPTER I Commensalism Introduction-commensalism in marine animals-fishes and sea anemones-associations on coral reefs-widespread nature of these relationships-hermit crabs and their associates CHAPTER II Commensalism in Terrestrial Animals Commensals of ants and termites-morphological modifications in symphiles-ants.and slavery-myrmecophilous plants . 16 CHAPTER III From Commensalism to Inquilinism and Parasitism Inquilinism-epizoites-intermittent parasites-general nature of modifications produced by parasitism 30 CHAPTER IV Adaptations to Parasitism in Annelids and Molluscs Polychates-molluscs; lamellibranchs; gastropods 40 CHAPTER V Adaptation to Parasitism in the Crustacea Isopoda-families of Epicarida-Rhizocephala-Ascothoracica
[Show full text]
COEVOLUTIONARY RELATIONSHIPS in a NEW TRIPARTITE MARINE SYMBIOSIS Phylogenetic Affinities of the Symbiotic Protist Nephromyces
COEVOLUTIONARY RELATIONSHIPS IN A NEW TRIPARTITE MARINE SYMBIOSIS Phylogenetic affinities of the symbiotic protist Nephromyces Mary Beth Saffo Marine Biological Laboratory, Woods Hole & Museum of Comparative Zoology, Harvard University Abstract 2. Phenotypic features suggestive of general protistan affinities All molgulid ascidian tunicates (Urochordata, phylum Chordata) : •tubular mitochondrial cristae (fig. 5,8) contain, in the lumen of the peculiar, ductless “renal sac,” an equally •thraustochytrid-like sporangia (fig. 4); other developmental stages bear vague peculiar symbiotic protist, Nephromyces. From the first description of resemblances to various other protistan taxa. Nephromyces in the 1870’s, the phylogenetic affinities, even existence, of this taxon has been a matter of debate. Though classified by Alfred Giard in 1888 as a chytridiomycete, Nephromyces has 3. Ssu rDNA sequences indicate that Nephromyces is an apicomplexan clade (preliminary phylogenetic analysis: a sample resisted definitive identification with any particular fungal or protistan Maximum likelihood trees shown) taxa. While its chitinous walls and hyphal-like cells support the notion of fungal affinities for Nephromyces, many other features , including the divergent phylogenetic implications of its morphologically eclectic life cycle , do not. Sequencing of ssu rDNA, indicates, however, that Nephromyces is an apicomplexan; these molecular data are supported by apicomplexan-like characters in the morphology Nephromyces’ host-transfer and infective stages. Other morphological and biochemical features of Nephromyces , some of Phylogenetic analyses, still in progress, consistently indicate thatNephromyces is a distinct them unusual among apicomplexa, or even protists generally, clade within the Apicomplexa. Although the challenge us to consider the significance of certain phenotypic relationship of Nephromyces to other apicomplexan characters as diagnostic tools in inferring deep phylogenies.
[Show full text]
Sea Squirt Symbionts! Or What I Did on My Summer Vacation… Leah Blasiak 2011 Microbial Diversity Course
Sea Squirt Symbionts! Or what I did on my summer vacation… Leah Blasiak 2011 Microbial Diversity Course Abstract Microbial symbionts of tunicates (sea squirts) have been recognized for their capacity to produce novel bioactive compounds. However, little is known about most tunicate-associated microbial communities, even in the embryology model organism Ciona intestinalis. In this project I explored 3 local tunicate species (Ciona intestinalis, Molgula manhattensis, and Didemnum vexillum) to identify potential symbiotic bacteria. Tunicate-specific bacterial communities were observed for all three species and their tissue specific location was determined by CARD-FISH. Introduction Tunicates and other marine invertebrates are prolific sources of novel natural products for drug discovery (reviewed in Blunt, 2010). Many of these compounds are biosynthesized by a microbial symbiont of the animal, rather than produced by the animal itself (Schmidt, 2010). For example, the anti-cancer drug patellamide, originally isolated from the colonial ascidian Lissoclinum patella, is now known to be produced by an obligate cyanobacterial symbiont, Prochloron didemni (Schmidt, 2005). Research on such microbial symbionts has focused on their potential for overcoming the “supply problem.” Chemical synthesis of natural products is often challenging and expensive, and isolation of sufficient quantities of drug for clinical trials from wild sources may be impossible or environmentally costly. Culture of the microbial symbiont or heterologous expression of the biosynthetic genes offers a relatively economical solution. Although the microbial origin of many tunicate compounds is now well established, relatively little is known about the extent of such symbiotic associations in tunicates and their biological function. Tunicates (or sea squirts) present an interesting system in which to study bacterial/eukaryotic symbiosis as they are deep-branching members of the Phylum Chordata (Passamaneck, 2005 and Buchsbaum, 1948).
[Show full text]
Real-Time Dynamics of Plasmodium NDC80 Reveals Unusual Modes of Chromosome Segregation During Parasite Proliferation Mohammad Zeeshan1,*, Rajan Pandey1,*, David J
© 2020. Published by The Company of Biologists Ltd | Journal of Cell Science (2021) 134, jcs245753. doi:10.1242/jcs.245753 RESEARCH ARTICLE SPECIAL ISSUE: CELL BIOLOGY OF HOST–PATHOGEN INTERACTIONS Real-time dynamics of Plasmodium NDC80 reveals unusual modes of chromosome segregation during parasite proliferation Mohammad Zeeshan1,*, Rajan Pandey1,*, David J. P. Ferguson2,3, Eelco C. Tromer4, Robert Markus1, Steven Abel5, Declan Brady1, Emilie Daniel1, Rebecca Limenitakis6, Andrew R. Bottrill7, Karine G. Le Roch5, Anthony A. Holder8, Ross F. Waller4, David S. Guttery9 and Rita Tewari1,‡ ABSTRACT eukaryotic organisms to proliferate, propagate and survive. During Eukaryotic cell proliferation requires chromosome replication and these processes, microtubular spindles form to facilitate an equal precise segregation to ensure daughter cells have identical genomic segregation of duplicated chromosomes to the spindle poles. copies. Species of the genus Plasmodium, the causative agents of Chromosome attachment to spindle microtubules (MTs) is malaria, display remarkable aspects of nuclear division throughout their mediated by kinetochores, which are large multiprotein complexes life cycle to meet some peculiar and unique challenges to DNA assembled on centromeres located at the constriction point of sister replication and chromosome segregation. The parasite undergoes chromatids (Cheeseman, 2014; McKinley and Cheeseman, 2016; atypical endomitosis and endoreduplication with an intact nuclear Musacchio and Desai, 2017; Vader and Musacchio, 2017). Each membrane and intranuclear mitotic spindle. To understand these diverse sister chromatid has its own kinetochore, oriented to facilitate modes of Plasmodium cell division, we have studied the behaviour movement to opposite poles of the spindle apparatus. During and composition of the outer kinetochore NDC80 complex, a key part of anaphase, the spindle elongates and the sister chromatids separate, the mitotic apparatus that attaches the centromere of chromosomes to resulting in segregation of the two genomes during telophase.
[Show full text]
Protist Phylogeny and the High-Level Classification of Protozoa
Europ. J. Protistol. 39, 338–348 (2003) © Urban & Fischer Verlag http://www.urbanfischer.de/journals/ejp Protist phylogeny and the high-level classification of Protozoa Thomas Cavalier-Smith Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK; E-mail: [email protected] Received 1 September 2003; 29 September 2003. Accepted: 29 September 2003 Protist large-scale phylogeny is briefly reviewed and a revised higher classification of the kingdom Pro- tozoa into 11 phyla presented. Complementary gene fusions reveal a fundamental bifurcation among eu- karyotes between two major clades: the ancestrally uniciliate (often unicentriolar) unikonts and the an- cestrally biciliate bikonts, which undergo ciliary transformation by converting a younger anterior cilium into a dissimilar older posterior cilium. Unikonts comprise the ancestrally unikont protozoan phylum Amoebozoa and the opisthokonts (kingdom Animalia, phylum Choanozoa, their sisters or ancestors; and kingdom Fungi). They share a derived triple-gene fusion, absent from bikonts. Bikonts contrastingly share a derived gene fusion between dihydrofolate reductase and thymidylate synthase and include plants and all other protists, comprising the protozoan infrakingdoms Rhizaria [phyla Cercozoa and Re- taria (Radiozoa, Foraminifera)] and Excavata (phyla Loukozoa, Metamonada, Euglenozoa, Percolozoa), plus the kingdom Plantae [Viridaeplantae, Rhodophyta (sisters); Glaucophyta], the chromalveolate clade, and the protozoan phylum Apusozoa (Thecomonadea, Diphylleida). Chromalveolates comprise kingdom Chromista (Cryptista, Heterokonta, Haptophyta) and the protozoan infrakingdom Alveolata [phyla Cilio- phora and Miozoa (= Protalveolata, Dinozoa, Apicomplexa)], which diverged from a common ancestor that enslaved a red alga and evolved novel plastid protein-targeting machinery via the host rough ER and the enslaved algal plasma membrane (periplastid membrane).
[Show full text]
Plenary Lecture & Symposium
PLENARY LECTURE & SYMPOSIUM SYMPOSIuM From genomics to flagellar and ciliary struc - MONDAY 29 JulY tures and cytoskeleton dynamics (by FEPS) PlENARY lECTuRE (ISoP Honorary Member lECTuRE) Chairs (by ISoP) Cristina Miceli , University of Camerino, Camerino, Italy Helena Soares , University of Lisbon and Gulbenkian Foun - Introduction - John Dolan , CNRS-Sorbonne University, Ville - dation, Lisbon, Portugal franche-sur-Mer, France. Jack Sunter - Oxford Brookes University, Oxford, UK- Genome Tom Fenchel University of Copenhagen, Copenhagen, Den - wide tagging in trypanosomes uncovers flagellum asymmetries mark Dorota Wloga - Nencki Institute of Experimental Biology, War - ISoP Honorary Member saw, Poland - Deciphering the molecular mechanisms that coor - dinate ciliary outer doublet complexes – search for “missing Size, Shape and Function among Protozoa links” Helena Soares - University of Lisbon and Polytechnic Institute of Lisbon, Lisbon, Portugal - From centrosomal microtubule an - SYMPOSIuM on ciliate biology and taxonomy in memory choring and organization to basal body positioning: TBCCD1 an of Denis lynn (by FEPS/ISoP) elusive protein Chairs Pierangelo luporini , University of Camerino, Camerino, Italy Roberto Docampo , University of Georgia, Athens, Georgia TuESDAY 30 JulY Alan Warren - Natural History Museum, London, UK. The bio - logy and systematics of peritrich ciliates: old concepts and new PlENARY lECTuRE (PAST-PRESIDENT LECTURE, by ISoP) findings Rebecca Zufall - University of Houston, Houston, USA. Amitosis Introduction - Avelina Espinosa , Roger Williams University, and the Evolution of Asexuality in Tetrahymena Ciliates Bristol, USA Sabine Agatha - University of Salzburg, Salzburg, Austria. The biology and systematics of oligotrichean ciliates: new findings David Bass and old concepts Natural History Museum London, London & Cefas, Weymouth, laura utz - School of Sciences, PUCRS, Porto Alegre, Brazil.
[Show full text]
Supplementary Materials - Methods
Supplementary Materials - Methods Bacterial Phylogeny Using the predicted phylogenetic positions from the Microbial Gene Atlas (MiGA), all complete genomes for the classes betaproteobacteria, alphaproteobacteria, and Bacteroides available on NCBI were collected. The GToTree pipeline was run on each of these datasets, including the Nephromyces endosymbiont, using the relevant HMM set of single copy gene targets (57–62). This included 138 gene targets and 722 genomes in alphaproteobacteria, 203 gene targets and 471 genomes in betaproteobacteria, and 90 gene targets and 388 genomes in Bacteroidetes. In betaproteobacteria, 5 genomes were removed for having either too few hits to the single copy gene targets, or multiple hits. The final trees were created with FastTree v2 (63), and formatted in FigTree (S Figure 2,3). Amplicon Methods Detailed Fifty Molgula manhattensis tunicates were collected from a single floating dock located in Greenwich Bay, RI (41.653N, -71.452W), and 29 Molgula occidentalis were collected from Alligator Harbor, FL (29.899N, -84.381W) by Gulf Specimens Marine Laboratories, Inc. (https://gulfspecimen.org/). All 79 samples were collected in August of 2016 and prepared for a single Illumina MiSeq flow cell (hereafter referred to as Run One). An additional 25 Molgula occidentalis were collected by Gulf Specimens Marine Laboratories, Inc. in March of 2018 from the same location and prepared for a second MiSeq flow cell (hereafter referred to as Run Two). Tunicates were dissected to remove renal sacs and Nephromyces cells contained within were collected by a micropipette and placed in 1.5 ml eppendorf tubes. Dissecting tools were sterilized in a 10% bleach solution for 15 min and then rinsed between tunicates.
[Show full text]
Phylogenomics Identifies a New Major Subgroup of Apicomplexans
GBE Phylogenomics Identiﬁes a New Major Subgroup of Apicomplexans, Marosporida class nov., with Extreme Apicoplast Genome Reduction Varsha Mathur1,*, Waldan K. Kwong1, Filip Husnik 2, Nicholas A.T. Irwin 1, Arni Kristmundsson3, Camino Gestal4, Mark Freeman5, and Patrick J. Keeling1 Downloaded from https://academic.oup.com/gbe/article/13/2/evaa244/5988525 by guest on 16 March 2021 1Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada 2Okinawa Institute of Science and Technology, Okinawa, Japan 3Fish Disease Laboratory, Institute for Experimental Pathology, University of Iceland, Reykjavık, Iceland 4Institute of Marine Research (IIM-CSIC), Vigo, Spain 5Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis, West Indies *Corresponding author: E-mail: [email protected]. Accepted: 17 November 2020 Abstract The phylum Apicomplexa consists largely of obligate animal parasites that include the causative agents of human diseases such as malaria. Apicomplexans have also emerged as models to study the evolution of nonphotosynthetic plastids, as they contain a relict chloroplast known as the apicoplast. The apicoplast offers important clues into how apicomplexan parasites evolved from free-living ancestors and can provide insights into reductive organelle evolution. Here, we sequenced the transcriptomes and apicoplast genomes of three deep-branching apicomplexans, Margolisiella islandica, Aggregata octopiana,andMerocystis kathae. Phylogenomic analyses show that these taxa, together with Rhytidocystis, form a new lineage of apicomplexans that is sister to the Coccidia and Hematozoa (the lineages including most medically signiﬁcant taxa). Members of this clade retain plastid genomes and the canonical apicomplexan plastid metabolism. However, the apicoplast genomes of Margolisiella and Rhytidocystis are the most reduced of any apicoplast, are extremely GC-poor, and have even lost genes for the canonical plastidial RNA polymerase.
[Show full text]
Conservation of Peripheral Nervous System Formation Mechanisms in Divergent Ascidian Embryos
RESEARCH ARTICLE Conservation of peripheral nervous system formation mechanisms in divergent ascidian embryos Joshua F Coulcher1†, Agne` s Roure1†, Rafath Chowdhury1, Me´ ryl Robert1, Laury Lescat1‡, Aure´ lie Bouin1§, Juliana Carvajal Cadavid1, Hiroki Nishida2, Se´ bastien Darras1* 1Sorbonne Universite´, CNRS, Biologie Inte´grative des Organismes Marins (BIOM), Banyuls-sur-Mer, France; 2Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan Abstract Ascidians with very similar embryos but highly divergent genomes are thought to have undergone extensive developmental system drift. We compared, in four species (Ciona and Phallusia for Phlebobranchia, Molgula and Halocynthia for Stolidobranchia), gene expression and gene regulation for a network of six transcription factors regulating peripheral nervous system *For correspondence: (PNS) formation in Ciona. All genes, but one in Molgula, were expressed in the PNS with some [email protected] differences correlating with phylogenetic distance. Cross-species transgenesis indicated strong † These authors contributed levels of conservation, except in Molgula, in gene regulation despite lack of sequence conservation equally to this work of the enhancers. Developmental system drift in ascidians is thus higher for gene regulation than Present address: ‡Department for gene expression and is impacted not only by phylogenetic distance, but also in a clade-specific of Developmental and Molecular manner and unevenly within a network. Finally, considering that Molgula is divergent in our Biology, Albert Einstein College analyses, this suggests deep conservation of developmental mechanisms in ascidians after 390 My of Medicine, New York, United of separate evolution. States; §Toulouse Biotechnology Institute, Universite´de Toulouse, CNRS, INRAE, INSA, Toulouse, France Competing interests: The Introduction authors declare that no The formation of an animal during embryonic development is controlled by the exquisitely precise competing interests exist.
[Show full text]
Pedunculate Molgula Species (Ascidiidae, Molgulidae) from the French Antarctic Sector
Zootaxa 3920 (1): 171–197 ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ Article ZOOTAXA Copyright © 2015 Magnolia Press ISSN 1175-5334 (online edition) http://dx.doi.org/10.11646/zootaxa.3920.1.9 http://zoobank.org/urn:lsid:zoobank.org:pub:C6BB0C5A-3317-4119-9C41-02F0EC487A9E Pedunculate Molgula species (Ascidiidae, Molgulidae) from the French Antarctic sector. Redescription and taxonomic revision FRANÇOISE MONNIOT1 & AGNÈS DETTAI2 1Muséum national d’Histoire naturelle, DMPA, 57 rue Cuvier Fr 75231 Paris cedex 05, France. E-mail: [email protected] 2Institut de systématique et Evolution, YSYEB-UMR 7205, UMPC EPHE Muséum national d’Histoire naturelle CP 26, 57 rue Cuvier 75231 Paris cedex 05 France. E-mail: [email protected] Abstract Following the Challenger Expedition in the southern Hemisphere, several international surveys have studied Antarctic as- cidians. Several pedunculate Molgula were successively described under various names. From the French part of the Ant- arctic continent and the Kerguelen area, numerous Molgula were recently collected. They are described here in different species, but closely allied. Their taxonomy is revised with an historical review of the most detailed publications and a link to the ancient names. Key words: Antarctic, Ascidians, Molgula species Introduction From the nineteenth century successive expeditions have investigated the benthic marine invertebrate fauna around the Antarctic continent. The “Challenger Expedition” (1873–1876) was the first to collect a large amount of invertebrates at different depths. Later, simultaneous surveys have also explored the southern ocean: the “Deutsch Sud-Polar Expedition” (1901–1903), the British “National Expedition” (1901–1904), the “Swedish Antarctic Expedition” (1901–1903), the “French Antarctic Expedition” (1903–1905), the “Australian Antarctic Expedition” (1911–1914).
[Show full text]
VII EUROPEAN CONGRESS of PROTISTOLOGY in Partnership with the INTERNATIONAL SOCIETY of PROTISTOLOGISTS (VII ECOP - ISOP Joint Meeting)
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/283484592 FINAL PROGRAMME AND ABSTRACTS BOOK - VII EUROPEAN CONGRESS OF PROTISTOLOGY in partnership with THE INTERNATIONAL SOCIETY OF PROTISTOLOGISTS (VII ECOP - ISOP Joint Meeting) Conference Paper · September 2015 CITATIONS READS 0 620 1 author: Aurelio Serrano Institute of Plant Biochemistry and Photosynthesis, Joint Center CSIC-Univ. of Seville, Spain 157 PUBLICATIONS 1,824 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Use Tetrahymena as a model stress study View project Characterization of true-branching cyanobacteria from geothermal sites and hot springs of Costa Rica View project All content following this page was uploaded by Aurelio Serrano on 04 November 2015. The user has requested enhancement of the downloaded file. VII ECOP - ISOP Joint Meeting / 1 Content VII ECOP - ISOP Joint Meeting ORGANIZING COMMITTEES / 3 WELCOME ADDRESS / 4 CONGRESS USEFUL / 5 INFORMATION SOCIAL PROGRAMME / 12 CITY OF SEVILLE / 14 PROGRAMME OVERVIEW / 18 CONGRESS PROGRAMME / 19 Opening Ceremony / 19 Plenary Lectures / 19 Symposia and Workshops / 20 Special Sessions - Oral Presentations / 35 by PhD Students and Young Postdocts General Oral Sessions / 37 Poster Sessions / 42 ABSTRACTS / 57 Plenary Lectures / 57 Oral Presentations / 66 Posters / 231 AUTHOR INDEX / 423 ACKNOWLEDGMENTS-CREDITS / 429 President of the Organizing Committee Secretary of the Organizing Committee Dr. Aurelio Serrano
[Show full text]
Phylum: Chordata
PHYLUM: CHORDATA Authors Shirley Parker-Nance1 and Lara Atkinson2 Citation Parker-Nance S. and Atkinson LJ. 2018. Phylum Chordata In: Atkinson LJ and Sink KJ (eds) Field Guide to the Ofshore Marine Invertebrates of South Africa, Malachite Marketing and Media, Pretoria, pp. 477-490. 1 South African Environmental Observation Network, Elwandle Node, Port Elizabeth 2 South African Environmental Observation Network, Egagasini Node, Cape Town 477 Phylum: CHORDATA Subphylum: Tunicata Sea squirts and salps Urochordates, commonly known as tunicates Class Thaliacea (Salps) or sea squirts, are a subphylum of the Chordata, In contrast with ascidians, salps are free-swimming which includes all animals with dorsal, hollow in the water column. These organisms also ilter nerve cords and notochords (including humans). microscopic particles using a pharyngeal mucous At some stage in their life, all chordates have slits net. They move using jet propulsion and often at the beginning of the digestive tract (pharyngeal form long chains by budding of new individuals or slits), a dorsal nerve cord, a notochord and a post- blastozooids (asexual reproduction). These colonies, anal tail. The adult form of Urochordates does not or an aggregation of zooids, will remain together have a notochord, nerve cord or tail and are sessile, while continuing feeding, swimming, reproducing ilter-feeding marine animals. They occur as either and growing. Salps can range in size from 15-190 mm solitary or colonial organisms that ilter plankton. in length and are often colourless. These organisms Seawater is drawn into the body through a branchial can be found in both warm and cold oceans, with a siphon, into a branchial sac where food particles total of 52 known species that include South Africa are removed and collected by a thin layer of mucus within their broad distribution.
[Show full text]