The First Record of a Rare Marine Tardigrade, Halobiotus
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Meiofauna of the Koster-Area, Results from a Workshop at the Sven Lovén Centre for Marine Sciences (Tjärnö, Sweden)
1 Meiofauna Marina, Vol. 17, pp. 1-34, 16 tabs., March 2009 © 2009 by Verlag Dr. Friedrich Pfeil, München, Germany – ISSN 1611-7557 Meiofauna of the Koster-area, results from a workshop at the Sven Lovén Centre for Marine Sciences (Tjärnö, Sweden) W. R. Willems 1, 2, *, M. Curini-Galletti3, T. J. Ferrero 4, D. Fontaneto 5, I. Heiner 6, R. Huys 4, V. N. Ivanenko7, R. M. Kristensen6, T. Kånneby 1, M. O. MacNaughton6, P. Martínez Arbizu 8, M. A. Todaro 9, W. Sterrer 10 and U. Jondelius 1 Abstract During a two-week workshop held at the Sven Lovén Centre for Marine Sciences on Tjärnö, an island on the Swedish west-coast, meiofauna was studied in a large variety of habitats using a wide range of sampling tech- niques. Almost 100 samples coming from littoral beaches, rock pools and different types of sublittoral sand- and mudflats yielded a total of 430 species, a conservative estimate. The main focus was on acoels, proseriate and rhabdocoel flatworms, rotifers, nematodes, gastrotrichs, copepods and some smaller taxa, like nemertodermatids, gnathostomulids, cycliophorans, dorvilleid polychaetes, priapulids, kinorhynchs, tardigrades and some other flatworms. As this is a preliminary report, some species still have to be positively identified and/or described, as 157 species were new for the Swedish fauna and 27 are possibly new to science. Each taxon is discussed separately and accompanied by a detailed species list. Keywords: biodiversity, species list, biogeography, faunistics 1 Department of Invertebrate Zoology, Swedish Museum of Natural History, Box 50007, SE-104 05, Sweden; e-mail: [email protected], [email protected] 2 Research Group Biodiversity, Phylogeny and Population Studies, Centre for Environmental Sciences, Hasselt University, Campus Diepenbeek, Agoralaan, Building D, B-3590 Diepenbeek, Belgium; e-mail: [email protected] 3 Department of Zoology and Evolutionary Genetics, University of Sassari, Via F. -
Diapause in Tardigrades: a Study of Factors Involved in Encystment
2296 The Journal of Experimental Biology 211, 2296-2302 Published by The Company of Biologists 2008 doi:10.1242/jeb.015131 Diapause in tardigrades: a study of factors involved in encystment Roberto Guidetti1,*, Deborah Boschini2, Tiziana Altiero2, Roberto Bertolani2 and Lorena Rebecchi2 1Department of the Museum of Paleobiology and Botanical Garden, Via Università 4, 41100, Modena, Italy and 2Department of Animal Biology, University of Modena and Reggio Emilia, Via Campi 213/D, 41100, Modena, Italy *Author for correspondence (e-mail: [email protected]) Accepted 12 May 2008 SUMMARY Stressful environmental conditions limit survival, growth and reproduction, or these conditions induce resting stages indicated as dormancy. Tardigrades represent one of the few animal phyla able to perform both forms of dormancy: quiescence and diapause. Different forms of cryptobiosis (quiescence) are widespread and well studied, while little attention has been devoted to the adaptive meaning of encystment (diapause). Our goal was to determine the environmental factors and token stimuli involved in the encystment process of tardigrades. The eutardigrade Amphibolus volubilis, a species able to produce two types of cyst (type 1 and type 2), was considered. Laboratory experiments and long-term studies on cyst dynamics of a natural population were conducted. Laboratory experiments demonstrated that active tardigrades collected in April produced mainly type 2 cysts, whereas animals collected in November produced mainly type 1 cysts, indicating that the different responses are functions of the physiological state at the time they were collected. The dynamics of the two types of cyst show opposite seasonal trends: type 2 cysts are present only during the warm season and type 1 cysts are present during the cold season. -
Tardigrade Reproduction and Food
Glime, J. M. 2017. Tardigrade Reproduction and Food. Chapt. 5-2. In: Glime, J. M. Bryophyte Ecology. Volume 2. Bryological 5-2-1 Interaction. Ebook sponsored by Michigan Technological University and the International Association of Bryologists. Last updated 18 July 2020 and available at <http://digitalcommons.mtu.edu/bryophyte-ecology2/>. CHAPTER 5-2 TARDIGRADE REPRODUCTION AND FOOD TABLE OF CONTENTS Life Cycle and Reproductive Strategies .............................................................................................................. 5-2-2 Reproductive Strategies and Habitat ............................................................................................................ 5-2-3 Eggs ............................................................................................................................................................. 5-2-3 Molting ......................................................................................................................................................... 5-2-7 Cyclomorphosis ........................................................................................................................................... 5-2-7 Bryophytes as Food Reservoirs ........................................................................................................................... 5-2-8 Role in Food Web ...................................................................................................................................... 5-2-12 Summary .......................................................................................................................................................... -
A Checklist of Norwegian Tardigrada
Fauna norvegica 2017 Vol. 37: 25-42. A checklist of Norwegian Tardigrada Terje Meier1 Meier T. 2017. A checklist of Norwegian Tardigrada. Fauna norvegica 37: 25-42. Animals of the phylum Tardigrada are microscopical metazoans that seldom exceed 1 mm in length. They are recorded from terrestrial, limnic and marine habitats and they have a distribution from Arctic to Antarctica. Tardigrades are also named ‘water bears’ referring to their ‘walk’ that resembles a bear’s gait. Knowledge of Norwegian tardigrades is fragmented and distributed across numerous sources. Here this information is gathered and validity of some records is discussed. In total 146 different species are recorded from the Norwegian mainland and Svalbard. Among these, 121 species and subspecies are recorded in previous publications and another 25 species are recorded from Norway for the first time. doi: 10.5324/fn.v37i0.2269. Received: 2017-05-22. Accepted: 2017-12-06. Published online: 2017-12.20. ISSN: 1891-5396 (electronic). Keywords: Tardigrada, Norway, Svalbard, checklist, taxonomy, literature, biodiversity, new records 1. Prinsdalsfaret 20, NO-1262 Oslo, Norway. Corresponding author: Terje Meier E-mail: [email protected] INTRODUCTION terminating in claws or sucking disks. The first three pairs of legs are directed ventrolaterally and are used to moving over the The phylum Tardigrada (water bears) currently holds about substrate. The hind legs are directed posteriorly and are used for 1250 valid species and subspecies (Degma et al. 2007, Degma grasping. Adult Tardigrades usually range from 250 µm to 700 et al. 2017) and are found in a great variety of habitats. They µm in length. -
Dwelling Eutardigrade Hypsibius Klebelsbergi MIHEL…I…, 1959 (Tardigrada)
Hamburg, Dezember 2007 Mitt. hamb. zool. Mus. Inst. Band 104 S. 61-72 ISSN 0072 9612 The osmoregulatory/excretory organs of the glacier- dwelling eutardigrade Hypsibius klebelsbergi MIHEL…I…, 1959 (Tardigrada) BEATE PELZER1, HIERONYMUS DASTYCH2 & HARTMUT GREVEN1 1 Institut für Zoomorphologie und Zellbiologie der Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany. E-mail: [email protected]. 2 Universität Hamburg, Biozentrum Grindel und Zoologisches Museum, Martin-Luther-King- Platz 3, 20146 Hamburg, Germany. E-mail: [email protected]. ABSTRACT. – The glacier-dwelling eutardigrade Hypsibius klebelsbergi MIHEL…I…, 1959 is exclusively known from cryoconite holes, i.e., water-filled micro-caverns on the glacier surface. This highly specialized environment is characterized by near zero temperatures and an extreme low conductivity of the water in these holes. Especially low conductivity might require powerful organs of osmoregulation in this unique species. Therefore we examined these organs in H. klebelsbergi using light and electron microscopy. H. klebelsbergi possesses three large Malpighian tubules at the transition of the midgut to the hindgut. Each tubule consists of a three- lobed distal, a thin middle and a short proximal part. The latter opens at the junction of the midgut and rectum. The distal part consists of three cells, which are characterized by a large nucleus, a fair number of mitochondria, a basal labyrinth, interdigitating plasma membranes and an irregular surface. Apical spaces extend in the middle part, which largely lacks nuclei and probably is made of offshoots of the proximal part. Here basal infolding and mitochondria are sparse. Interwoven cell projections and microvilli give this part and the proximal part a vacuolated appearance. -
Distribution and Diversity of Tardigrada Along Altitudinal Gradients in the Hornsund, Spitsbergen
RESEARCH/REVIEW ARTICLE Distribution and diversity of Tardigrada along altitudinal gradients in the Hornsund, Spitsbergen (Arctic) Krzysztof Zawierucha,1 Jerzy Smykla,2,3 Łukasz Michalczyk,4 Bartłomiej Gołdyn5,6 & Łukasz Kaczmarek1,6 1 Department of Animal Taxonomy and Ecology, Faculty of Biology, Adam Mickiewicz University in Poznan´ , Umultowska 89, PL-61-614 Poznan´ , Poland 2 Department of Biodiversity, Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, PL-31-120 Krako´ w, Poland 3 Present address: Department of Biology and Marine Biology, University of North Carolina, Wilmington, 601 S. College Rd., Wilmington, NC 28403, USA 4 Department of Entomology, Institute of Zoology, Jagiellonian University, Gronostajowa 9, PL-30-387 Krako´ w, Poland 5 Department of General Zoology, Faculty of Biology, A. Mickiewicz University in Poznan´ , Umultowska 89, PL-61-614 Poznan´ , Poland 6 Laboratorio de Ecologı´a Natural y Aplicada de Invertebrados, Universidad Estatal Amazo´ nica, Puyo, Ecuador Keywords Abstract Arctic; biodiversity; climate change; invertebrate ecology; Milnesium; Two transects were established and sampled along altitudinal gradients on the Tardigrada. slopes of Ariekammen (77801?N; 15831?E) and Rotjesfjellet (77800?N; 15822?E) in Hornsund, Spitsbergen. In total 59 moss, lichen, liverwort and mixed mossÁ Correspondence lichen samples were collected and 33 tardigrade species of Hetero- and Krzysztof Zawierucha, Department of Eutardigrada were found. The a diversity ranged from 1 to 8 per sample; the Animal Taxonomy and Ecology, Faculty of estimated number of species based on all analysed samples was 52917 for the Biology, Adam Mickiewicz University in Chao 2 estimator and 41 for the incidence-based coverage estimator. -
An Integrative Redescription of Hypsibius Dujardini (Doyère, 1840), the Nominal Taxon for Hypsibioidea (Tardigrada: Eutardigrada)
Zootaxa 4415 (1): 045–075 ISSN 1175-5326 (print edition) http://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2018 Magnolia Press ISSN 1175-5334 (online edition) https://doi.org/10.11646/zootaxa.4415.1.2 http://zoobank.org/urn:lsid:zoobank.org:pub:AA49DFFC-31EB-4FDF-90AC-971D2205CA9C An integrative redescription of Hypsibius dujardini (Doyère, 1840), the nominal taxon for Hypsibioidea (Tardigrada: Eutardigrada) PIOTR GĄSIOREK, DANIEL STEC, WITOLD MOREK & ŁUKASZ MICHALCZYK* Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland *Corresponding author. E-mail: [email protected] Abstract A laboratory strain identified as “Hypsibius dujardini” is one of the best studied tardigrade strains: it is widely used as a model organism in a variety of research projects, ranging from developmental and evolutionary biology through physiol- ogy and anatomy to astrobiology. Hypsibius dujardini, originally described from the Île-de-France by Doyère in the first half of the 19th century, is now the nominal species for the superfamily Hypsibioidea. The species was traditionally con- sidered cosmopolitan despite the fact that insufficient, old and sometimes contradictory descriptions and records prevent- ed adequate delineations of similar Hypsibius species. As a consequence, H. dujardini appeared to occur globally, from Norway to Samoa. In this paper, we provide the first integrated taxonomic redescription of H. dujardini. In addition to classic imaging by light microscopy and a comprehensive morphometric dataset, we present scanning electron photomi- crographs, and DNA sequences for three nuclear markers (18S rRNA, 28S rRNA, ITS-2) and one mitochondrial marker (COI) that are characterised by various mutation rates. -
The Early History of the Metazoa—A Paleontologist's Viewpoint
ISSN 20790864, Biology Bulletin Reviews, 2015, Vol. 5, No. 5, pp. 415–461. © Pleiades Publishing, Ltd., 2015. Original Russian Text © A.Yu. Zhuravlev, 2014, published in Zhurnal Obshchei Biologii, 2014, Vol. 75, No. 6, pp. 411–465. The Early History of the Metazoa—a Paleontologist’s Viewpoint A. Yu. Zhuravlev Geological Institute, Russian Academy of Sciences, per. Pyzhevsky 7, Moscow, 7119017 Russia email: [email protected] Received January 21, 2014 Abstract—Successful molecular biology, which led to the revision of fundamental views on the relationships and evolutionary pathways of major groups (“phyla”) of multicellular animals, has been much more appre ciated by paleontologists than by zoologists. This is not surprising, because it is the fossil record that provides evidence for the hypotheses of molecular biology. The fossil record suggests that the different “phyla” now united in the Ecdysozoa, which comprises arthropods, onychophorans, tardigrades, priapulids, and nemato morphs, include a number of transitional forms that became extinct in the early Palaeozoic. The morphology of these organisms agrees entirely with that of the hypothetical ancestral forms reconstructed based on onto genetic studies. No intermediates, even tentative ones, between arthropods and annelids are found in the fos sil record. The study of the earliest Deuterostomia, the only branch of the Bilateria agreed on by all biological disciplines, gives insight into their early evolutionary history, suggesting the existence of motile bilaterally symmetrical forms at the dawn of chordates, hemichordates, and echinoderms. Interpretation of the early history of the Lophotrochozoa is even more difficult because, in contrast to other bilaterians, their oldest fos sils are preserved only as mineralized skeletons. -
X-Ray Imaging of a Water Bear Offers a New Look at Tardigrade Internal
Gross et al. Zoological Letters (2019) 5:14 https://doi.org/10.1186/s40851-019-0130-6 RESEARCHARTICLE Open Access X-ray imaging of a water bear offers a new look at tardigrade internal anatomy Vladimir Gross1*† , Mark Müller2*†, Lorenz Hehn2, Simone Ferstl2, Sebastian Allner2, Martin Dierolf2, Klaus Achterhold2, Georg Mayer1† and Franz Pfeiffer2,3† Abstract Background: Tardigrades (water bears) are microscopic invertebrates of which the anatomy has been well studied using traditional techniques, but a comprehensive three-dimensional reconstruction has never been performed. In order to close this gap, we employed X-ray computed tomography (CT), a technique that is becoming increasingly popular in zoology for producing high-resolution, three-dimensional (3D) scans of whole specimens. While CT has long been used to scan larger samples, its use in some microscopic animals can be problematic, as they are often too small for conventional CT yet too large for high-resolution, optics-based soft X-ray microscopy. This size gap continues to be narrowed with advancements in technology, with high-resolution imaging now being possible using both large synchrotron devices and, more recently, laboratory-based instruments. Results: Here we use a recently developed prototype lab-based nano-computed tomography device to image a 152 μm-long tardigrade at high resolution (200–270 nm pixel size). The resulting dataset allowed us to visualize the anatomy of the tardigrade in 3D and analyze the spatial relationships of the internal structures. Segmentation of the major structures of the body enabled the direct measurement of their respective volumes. Furthermore, we segmented every storage cell individually and quantified their volume distribution. -
Number 69 August 2017
Number 69 (August 2017) The Malacologist Page 1 NUMBER 69 AUGUST 2017 Contents Editorial …………………………….. ..............................2 in memoriam Notices …………………………………………………….2 Elizabeth Anne Platts ………………………………………….19 Research Grant Report Past Award Winners of the Society - A cavalcade of excellence…………………………. …..21 Forthcoming Meetings Jorge A Audino Molluscan Forum .......................................................................27 …………………………………………………………………...3 AGM & Conference New perspectives on evolution in molluscs: from fossils to next generation sequencing ………………………………………….31 Travel Grant Report Grants and Awards Of The Society................................... 32 Membership Notices …………………………………….….…33 ……. 9 Annual general meeting—spring 2017 Annual Report of Council ..........................................................10 AGM Conference Symposium on Molluscan Colour and Vision Original notice ……………………………………. .15 abstracts ……………………………………………...16 This issue includes an extended abstract from the AGM conference on colour and vision in molluscs. The abstract was entitled :- Tricks of light, mirror, and color: The beautiful camou- flage of pelagic cephalopods by Sönke Johnsen See page 17 The Malacological Society of London was founded in 1893 and registered as a charity in 1978 (Charity Number 275980) Number 69 (August 2017) The Malacologist Page 2 EDITORIAL For a small, taxon-based Society, the ‘MalacSoc’ is remarkably generous in its grants and awards (see page 23). A list of this year’s awards is buried in the President’s Report of Council (page 12) and a full listing of all awards is given on page 21. IThe awards list makes instructive reading, as it points to the creative growing points of our discipline, especially in relation to the varied enthusiasms of young researchers. Through its travel awards, the Society has, over the years, given a positive boost to a great number of students who will, hopefully, remember the role the MalacSoc played in their career develop- ment. -
Analyses of Nervous System Patterning Genes in the Tardigrade Hypsibius Exemplaris Illuminate the Evolution of Panarthropod Brains Frank W
Smith et al. EvoDevo (2018) 9:19 https://doi.org/10.1186/s13227-018-0106-1 EvoDevo RESEARCH Open Access Analyses of nervous system patterning genes in the tardigrade Hypsibius exemplaris illuminate the evolution of panarthropod brains Frank W. Smith1,2* , Mandy Cumming1 and Bob Goldstein2 Abstract Background: Both euarthropods and vertebrates have tripartite brains. Several orthologous genes are expressed in similar regionalized patterns during brain development in both vertebrates and euarthropods. These similarities have been used to support direct homology of the tripartite brains of vertebrates and euarthropods. If the tripartite brains of vertebrates and euarthropods are homologous, then one would expect other taxa to share this structure. More generally, examination of other taxa can help in tracing the evolutionary history of brain structures. Tardigrades are an interesting lineage on which to test this hypothesis because they are closely related to euarthropods, and whether they have a tripartite brain or unipartite brain has recently been a focus of debate. Results: We tested this hypothesis by analyzing the expression patterns of six3, orthodenticle, pax6, unplugged, and pax2/5/8 during brain development in the tardigrade Hypsibius exemplaris—formerly misidentifed as Hypsibius dujardini. These genes were expressed in a staggered anteroposterior order in H. exemplaris, similar to what has been reported for mice and fies. However, only six3, orthodenticle, and pax6 were expressed in the developing brain. Unplugged was expressed broadly throughout the trunk and posterior head, before the appearance of the nervous system. Pax2/5/8 was expressed in the developing central and peripheral nervous system in the trunk. Conclusion: Our results buttress the conclusion of our previous study of Hox genes—that the brain of tardigrades is only homologous to the protocerebrum of euarthropods. -
First Record of Cysts in the Tidal Tardigrade Echiniscoides Sigismundi
Helgol Mar Res (2014) 68:531–537 DOI 10.1007/s10152-014-0409-0 ORIGINAL ARTICLE First record of cysts in the tidal tardigrade Echiniscoides sigismundi Lykke K. B. Clausen • Kasper N. Andersen • Thomas L. Hygum • Aslak Jørgensen • Nadja Møbjerg Received: 14 February 2014 / Revised: 14 July 2014 / Accepted: 15 July 2014 / Published online: 14 August 2014 Ó The Author(s) 2014. This article is published with open access at Springerlink.com Abstract Tardigrades are microscopic metazoans that Keywords Diapause Á Ecdysozoa Á Extreme withstand environmental extremes by entering dormant environments Á Intertidal Á Marine Á Osmotic stress states, such as cryptobiosis (latent life). In addition, they may also form cysts. Here, we present the first report of cyst formation in a marine heterotardigrade, i.e., Echini- Introduction scoides sigismundi, which constitutes a cryptic species complex present worldwide in tidal zones. The cysts were Tardigrades are microscopic metazoans that colonize eco- initially discovered during experimental series constructed systems worldwide and show great tolerance of environ- to investigate osmotic stress tolerance. The animals, which mental stress (e.g., Goldstein and Blaxter 2002; Nelson eventually formed cysts, showed signs of an imminent molt 2002; Møbjerg et al. 2011). Three major evolutionary lin- at the beginning of experimentation. We use the term eages are currently recognized: (1) eutardigrades and (2) ‘‘cyst’’ for stages, where a total of three or more cuticles mesotardigrades, which are predominantly semiterrestrial/ have been synthesized. Our observations show that limnic, and (3) heterotardigrades that split into the semi- encystment in E. sigismundi involves synthesizing of at terrestrial/tidal echiniscoideans and the marine arthrotar- least two new cuticle layers.