DOCSLIB.ORG

Hofstenia Spp., Acoela), with Notes on Color Variation and Genetic Variation Within the Genus

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hofstenia Spp., Acoela), with Notes on Color Variation and Genetic Variation Within the Genus Hydrobiologia (2007) 592:439–454 DOI 10.1007/s10750-007-0789-0 PRIMARY RESEARCH PAPER A revision of the systematics of panther worms (Hofstenia spp., Acoela), with notes on color variation and genetic variation within the genus Matthew Hooge Æ Andreas Wallberg Æ Christiane Todt Æ Aaron Maloy Æ Ulf Jondelius Æ Seth Tyler Received: 28 July 2006 / Revised: 12 May 2007 / Accepted: 17 May 2007 / Published online: 31 July 2007 Ó Springer Science+Business Media B.V. 2007 Abstract Species of the genus Hofstenia are islands of Bermuda and the Bahamas, and the voracious predators and among the largest and Caribbean and in a variety of habitats includ- most colorful of the Acoela. They are known ing the rocky intertidal, among Thalassia sea from Japan, the Red Sea, the North Atlantic grass, on filamentous algae and decaying man- grove leaves. Certain color morphs associated with each of these habitats seem to have confused the taxonomy of the group. While Handling editor: K. Martens brown-and-white banding and spotting patterns of Hofstenia miamia and Hofstenia giselae are Electronic supplementary material The online version of this article (doi:10.1007/s10750-007-0789-0) contains distinctive for species associated with mangrove supplementary material, which is available to authorized leaves and Thallasia sp. and are likely to be users. cryptic for these specific environments, we find some evidence to suggest that the coloration is M. Hooge (&) S. Tyler Department of BiologicalÁ Sciences, The University of mimicry of a nudibranch with aposematic Maine, Orono, ME 04469-5751, USA coloration. The common plan in these patterns e-mail: [email protected] is one with three variously solid or spotted lighter cross bands on a dark background. Our A. Wallberg Department of Systematic Zoology, Evolutionary examination of museum type material and live Biology Centre, Uppsala University, Norbyva¨gen specimens of Hofstenia collected from Baha- 18D, 752 36 Uppsala, Sweden mas, Belize, Bermuda, and Panama revealed no internal morphological differences between C. Todt Department of Biology, University of Bergen, the Hofstenia species occurring in the Carib- Thormøhlensgate 55, 5007 Bergen, Norway bean. Similarly, our analyses of 18S and 28S molecular sequence data revealed no significant A. Maloy differences among specimens. Accordingly, we Centre of Applied Marine Biotechnology, Letterkenny Institute of Technology, Letterkenny, declare that Hofstenia giselae is a junior syn- County Donegal, Ireland onym of Hofstenia miamia, the three-banded panther worm. U. Jondelius Department of Invertebrate Zoology, Swedish Keywords Platyhelminthes Turbellaria Museum of Natural History, POB 50007, 104 05 Á Á Stockholm, Sweden Mangrove Caribbean Intraspecific variation Á Á 123 440 Hydrobiologia (2007) 592:439–454 Introduction with sclerotized needles. Species of Hofstenia lack a female gonopore, but the sharp needles of the Species of the genus Hofstenia are among the everted penis can penetrate the body wall of the largest and most distinctive of the Acoela. They receiving worm and deposit sperm directly are voracious predators of micrometazoans, suck- beneath its epidermis (Bock, 1923); sperm then ing in prey with a capacious muscular pharynx at apparently migrate through the parenchymal the anterior tip of the body. Mature specimens tissue to the oocytes. are typically 4–9 mm in length and, rather than Such distinctive features made it difficult for being colorless and having the teardrop body early systematists to place Hofstenia among other shape of most acoel species, Hofstenia species are platyhelminths. The first described species, Hof- darkly pigmented, with patterns of white bands stenia atroviridis Bock, 1923, attracted consider- and spots, and nearly cylindrical in shape, often able attention for the primitive features of its with a small pointed tail (Fig. 1). Their carnivory nervous system and gut relative to those of other and color patterns, reminiscent of panthers in platyhelminths and for features of its reproduc- general, inspires their common name. tive system that seemed to be intermediate The large, muscular, anteriorly directed phar- between those of other primitive and the more ynx simplex is one-third to one-half the length of derived flatworms (Bock, 1923; Steinbo¨ ck, 1924; the entire worm (Fig. 2) and is used to suck up Bresslau, 1933; Karling, 1940). At first, similarity copepods, ostracods, and turbellarians. Also dis- of its reproductive organs and pharynx to those of tinctive of Hofstenia is its anteriorly positioned prolecithtophoran and some lecithoepitheliate male copulatory organ (Fig. 2). Located ventral turbellarians was weighed heavily in placing it to the pharynx, the copulatory organ is composed among such so-called ‘‘alloeocoels,’’ even though of a highly muscular, eversible penis equipped its affinity to the Acoela was recognized (Stein- Fig. 1 Dorsal aspect of eight specimens of Hofstenia miamia from Curac¸ao (from Correˆa, 1963) 123 Hydrobiologia (2007) 592:439–454 441 Fig. 2 Sagittal histological section of Hofstenia miamia mgp—male gonopore, phm—pharynx musculature, from Belize. cs—Digestive central syncytium, e—egg, st—penis stylets, sv—seminal vesicle gv—granule vesicle, m—mouth, ma—male antrum, bo¨ ck, 1924; Meixner, 1938; Karling, 1940). Not acquired the type material for H. atroviridis, H. until a quarter century after its discovery was its giselae, and H. miamia (Table 2) for comparison. true nature as an acoel established (Papi, 1957). We report here the results of our comparative Currently there are four described species of morphological study of this material. In addition, Hofstenia (see Tyler et al., 2006). The type we document the range in color patterns in species, H. atroviridis, is a dark, blackish green Caribbean specimens, and propose systematic species from the coast of Japan where it is found revision of the genus Hofstenia. Acoels have associated with coralline algae in tide pools and been attributed to possess unusually fast evolving on the holdfasts of Laminaria at subtidal depths nuclear ribosomal genes (Carranza et al., 1997; (Bock, 1923). H. miamia Correˆa, 1960, was Ruiz-Trillo et al., 1999), which may make these described from a single specimen found in algae molecular markers useful for studying closely at Miami, Florida (Correˆa, 1960); however, addi- related acoel lineages (e.g. Tekle et al., 2005). We tional specimens were subsequently found in therefore used 18S and 28S rDNA genes acquired Antigua as well as Curac¸ao (Correˆa, 1963) and from several specimens of Hofstenia from all four were used to document the variation in the dark- collection sites in an attempt to reconstruct a brown, white-banded color patterns within the molecular phylogeny of this taxon and test the species (Fig. 1). Soon thereafter, Steinbo¨ ck traditional classification. (1966) published a monograph on the Hofstenii- dae in which he established two new species: H. beltagii Steinbo¨ ck, 1966, from specimens collected Materials and methods in the Red Sea and first identified by Beltagi (1958) as H. atroviridis, and H. giselae Steinbo¨ ck, Collection and observation of living specimens 1966, collected from a Thalassia bed in the Bahamas. With his specimens of H. giselae, which Approximately 150 living specimens of Hofstenia were lighter-colored than the reported pigmenta- were collected from sites in Bahamas, Belize, tion of H. miamia, Steinbo¨ ck experimented Bermuda, and Panama (Table 1). The majority of extensively on their regenerative capabilities specimens we collected were taken from sub- (Steinbo¨ ck, 1966, 1967). merged, decaying mangrove leaves found in piles Over a 1-year period from April 2004 to May at the base of living mangroves, and had dark 2005, we collected living specimens of Hofstenia coloration that appeared most similar to Correˆa’s from Bahamas, Belize, Bermuda, and Panama (1963) H. miamia specimens (Fig. 1). A single (Table 1). Some of these were light-colored and specimen of H. miamia was also found on associated with Thalassia and filamentous algae, Penicillus attached to a mangrove root at Man- which we identified as H. giselae, and others dark atee Cay, Belize. We collected lightly colored and associated with decaying mangrove leaves, specimens of Hofstenia from a Thalassia sp. bed which we identified as H. miamia. We also at Carrie Bow Cay, Belize, and from filamentous 123 442 Hydrobiologia (2007) 592:439–454 25 20 25 25 25 ~ ~ ~ ~ ~ Stylet number 1 4 10 25 30 90 Specimens ~ ~ ~ ~ m) l 75 40 70 65 70 Stylet length ( (m) 1 1 1 1 Depth <1 <1 Subterminal Subterminal Subterminal Subterminal Subterminal Mouth root leaves leaves leaves Thalassia 0.3 0.4 0.4 0.4 0.5 Pharynx/ body ratio mangrove algae mangrove mangrove mangrove on underlying 1.3 1.0 1.0 1.7 2.1 Pharynx length (mm) Habitat filamentous Penicillus Submerged Submerged Sediment Submerged 4.2 2.5 3.7 3.9 4.2 Body length (mm) 2004 4 2004 2004 2004 2004 2005 assoc. Fig. in Date April April April August April May Thalassia green shown with (W) study Brown/white Brown/white White/brown White/brown Dark Color † † † † those 26 10 54 32 this ¢ ¢ ¢ ¢ ¢ ¢ 06 11 06 04 15 42 in ° ° ° ° ° ° Longitude 76 88 88 88 82 64 used including Corallina , , Thalassia (N) with † † † † algae 26 46 9 46 Hofstenia ¢ ¢ ¢ ¢ ¢ Hofstenia ¢ Laminaria 46 39 49 43 20 of intertidal/subtidal leaves ° ° ° ° ° of 21 submerged among assoc. and ° Latitude 16 9 23 16 32 16 with sections specimens mangrove Thalassia assoc. Low-energy Low-energy Low-energy High-energy Low-energy Habitat for station side side field ao ¸ histological Garden East of North STRI Belize Curac Belize Japan Bahamas Location information Island Pond, Cay, Grouper Toro, Cay 5 miamia giselae atroviridis 2508a Bow del Comparison Sampling Cays, III, Stocking 2 1 1096778 SMNH 74878/9 89913 NMW 12, USNM Paratype SMNH Lectotype Lectotype Lee Manatee Twin Carrie Bocas Walsingham SMNH Hofstenia Hofstenia Hofstenia Specimen Table Table Locality Bahamas Belize Panama Bermuda 123 Hydrobiologia (2007) 592:439–454 443 algae at the surface of a saltwater pond on Lee Gran˜ a’’ (Ferrol, Galiza, Spain) in August 2006 in Stocking Island, Bahamas.
Load more

Recommended publications
  • 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.
    [Show full text]
  • Spermiogenesis in the Acoel Symsagittifera Roscoffensis: Nucleus-Plasma
    bioRxiv preprint doi: https://doi.org/10.1101/828251; this version posted November 1, 2019. 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-ND 4.0 International license. Spermiogenesis in the acoel Symsagittifera roscoffensis: nucleus-plasma membrane contact sites and microtubules. Matthew J. Hayes1, Anne-C. Zakrzewski2, Tim P. Levine1 and Maximilian J. Telford2 1University College London Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK 2 Centre for Life’s Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK Running title: Contact sites and microtubule rearrangements in spermiogenesis Summary sentence: During spermiogenesis in the acoel flatworm Symsagittifera roscoffensis, two previously unidentified contact sites contribute to the structure of the mature spermatozoon and the axonemal structures show direct continuity between doublet and dense core microtubules. Keywords: Contact-site, acrosome, gamete biology, spermatid, spermatogenesis, spermiogenesis, acoel. bioRxiv preprint doi: https://doi.org/10.1101/828251; this version posted November 1, 2019. 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-ND 4.0 International license. Abstract Symsagittifera roscoffensis is a small marine worm found in the intertidal zone of sandy beaches around the European shores of the Atlantic. S. roscoffensis is a member of the Acoelomorpha, a group of flatworms formerly classified with the Platyhelminthes, but now recognised as Xenacoelomorpha, a separate phylum of disputed affinity.
    [Show full text]
  • 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.
    [Show full text]
  • Xenacoelomorpha's Significance for Understanding Bilaterian Evolution
    Available online at www.sciencedirect.com ScienceDirect Xenacoelomorpha’s significance for understanding bilaterian evolution Andreas Hejnol and Kevin Pang The Xenacoelomorpha, with its phylogenetic position as sister biology models are the fruitfly Drosophila melanogaster and group of the Nephrozoa (Protostomia + Deuterostomia), plays the nematode Caenorhabditis elegans, in which basic prin- a key-role in understanding the evolution of bilaterian cell types ciples of developmental processes have been studied in and organ systems. Current studies of the morphological and great detail. It might be because the field of evolutionary developmental diversity of this group allow us to trace the developmental biology — EvoDevo — has its origin in evolution of different organ systems within the group and to developmental biology and not evolutionary biology that reconstruct characters of the most recent common ancestor of species under investigation are often called ‘model spe- Xenacoelomorpha. The disparity of the clade shows that there cies’. Criteria for selected representative species are cannot be a single xenacoelomorph ‘model’ species and primarily the ease of access to collected material and strategic sampling is essential for understanding the evolution their ability to be cultivated in the lab [1]. In some cases, of major traits. With this strategy, fundamental insights into the a supposedly larger number of ancestral characters or a evolution of molecular mechanisms and their role in shaping dominant role in ecosystems have played an additional animal organ systems can be expected in the near future. role in selecting model species. These arguments were Address used to attract sufficient funding for genome sequencing Sars International Centre for Marine Molecular Biology, University of and developmental studies that are cost-intensive inves- Bergen, Thormøhlensgate 55, 5008 Bergen, Norway tigations.
    [Show full text]
  • The Ultrastructural Organization of Acoela and Their Phylogenetic Relationships
    Invertebrate Zoology, 2017, 14(2): 217–225 © INVERTEBRATE ZOOLOGY, 2017 The ultrastructural organization of Acoela and their phylogenetic relationships Ya.I. Zabotin Kazan (Volga region) Federal University, Kazan, 420008, Russia. E-mail: Yaroslav_Zabotin@ rambler.ru ABSTRACT: Acoela represent one of the most spectacular taxa in animal kingdom. Their phylogenetic position as well as a taxonomic rank widely varies in zoological literature from the order of flatworms to the separate phylum within the deuterostomes or the sister taxon of all other bilaterians. One of the reasons of the absence of consensus among morphologists and molecular biologists is the insufficient amount of fine structural data on Acoela. In the present work the new ultrastructural features of four species of Acoela (Archaphanostoma agile, Otocelis rubropunctata, Symsagittifera japonica and Amphiscolops sp.) from different families are described. Along with the archaic characteristics the new apomorphic morphological features of epidermis, body wall musculature and central syncytial paren- chyma of species studied were found. The cellular organization of acoels is characterized by the wide morphological diversity, however no significance of the secondarily simplifi- cation was found. The alternative views on phylogenetic affinities of Acoela are discussed, and the conclusion of progressive but not regressive evolution of this invertebrate group is proposed. How to cite this article: Zabotin Ya.I. 2017. The ultrastructural organization of Acoela and their phylogenetic relationships // Invert. Zool. Vol.14. No.2. P.217–225. doi: 10.15298/ invertzool.14.2.17 KEY WORDS: Acoela, morphology, ultrastructure, systematics, phylogeny. Ультраструктурная организация бескишечных турбеллярий (Acoela) и их филогенетические отношения Я.И. Заботин Казанский (Приволжский) федеральный университет, Казань, 420008, Россия.
    [Show full text]
  • (Platyhelminthes, Turbellaria, Polycladida) from Karachi Coast
    International Journal of Research Studies in Zoology (IJRSZ) Volume 2, Issue 2, 2016, PP 23-28 ISSN 2454-941X http://dx.doi.org/10.20431/2454-941X.0202005 www.arcjournals.org Short Notes on Marine Polycladids (Platyhelminthes, Turbellaria, Polycladida) from Karachi Coast Quddusi B. Kazmi Marine Reference Collection and Resource Centre, University of Karachi, Pakistan Abstract: Ten new records of marine polycladid worms are subject of the present notes from Pakistan. Each species is photographed and discussed briefly. 1. INTRODUCTION The Polycladida represents a highly diverse clade of free-living marine turbellarian flatworms. They are known from the littoral to the sub littoral zone. Although not related to molluscs, they are often mistaken for sea slugs because of their brilliant colour patterns. There is little known about the biodiversity of polycladid flatworms from the Indian Ocean. In Pakistan, studies on polycladids have remained neglected, first report was by Kazmi (1996), then Fatima and Barkati (1999) as Stylochoplanapallida reported Emprosthopharynxpallida (Quatrefage,1845) and latelyKazmi and Naushaba (2013) listed 4 unidentified species or only identified to genus level, of these , their unspecified genus Pseudocerosis now identified as belonging to Pseudocerossusanae Newman and Anderson ,1997 ,an undetermined pseudocertid is now named as Tytthosoceroslizardensis Newman and Cannon,1996 and another undetermined genus is given as Cestoplanarubrocinta (Grube, 1840) ,more species are added here;all are briefly described here
    [Show full text]
  • A Phylogenetic Analysis of Myosin Heavy Chain Type II Sequences Corroborates That Acoela and Nemertodermatida Are Basal Bilaterians
    A phylogenetic analysis of myosin heavy chain type II sequences corroborates that Acoela and Nemertodermatida are basal bilaterians I. Ruiz-Trillo*, J. Paps*, M. Loukota†, C. Ribera†, U. Jondelius‡, J. Bagun˜ a` *, and M. Riutort*§ *Departament de Gene`tica and †Departament de Biologia Animal, Universitat Barcelona, Av. Diagonal, 645 08028 Barcelona, Spain; and ‡Evolutionary Biology Centre, University Uppsala, Norbyva¨gen 18D, 752 36 Uppsala, Sweden Communicated by James W. Valentine, University of California, Berkeley, CA, June 28, 2002 (received for review April 15, 2002) Bilateria are currently subdivided into three superclades: Deuter- across all bilaterians. However different, this scheme also suited ostomia, Ecdysozoa, and Lophotrochozoa. Within this new taxo- alternative hypotheses such as the ‘‘set-aside cells’’ theory (13, nomic frame, acoelomate Platyhelminthes, for a long time held to 14) and the colonial ancestor theory (15). be basal bilaterians, are now considered spiralian lophotrochozo- This new status quo was soon questioned. A SSU-based study ans. However, recent 18S rDNA [small subunit (SSU)] analyses have using a large set of Platyhelminthes acoels and other metazoans shown Platyhelminthes to be polyphyletic with two of its orders, showed acoels to be the extant earliest branching bilaterians the Acoela and the Nemertodermatida, as the earliest extant (16), turning Platyhelminthes into a polyphyletic group. In bilaterians. To corroborate such position and avoid the criticisms of addition, Jenner (17) noted that phylogenies put forward to back saturation and long-branch effects thrown on the SSU molecule, the new metazoan molecular trees (10–12, 18) were incomplete we have searched for independent molecular data bearing good and heavily pruned.
    [Show full text]
  • New and Known Nemertodermatida (Platyhelminthes-Acoelomorpha)
    Belg. J. Zoo!. - Volume 128 (1998) - issue 1 - pages 55-92 - Brussels 1998 Received: 18 February 1998 NEW AND KNOWN NEMERTODERMATIDA (PLATYHELMINTHES-ACOELOMORPHA)... -A REVISION - WOLFGANG STERRER Bermuda Natural History Museum, Flatts FLBX, Bermuda e-mail [email protected] Abstract. Described in 1930-31 by Steinbiick who considered it the most primitive bilaterian, the turbellarian genus Nemertoderma is known for its rote in platyhelminth phylogeny as much as for its muddled taxonomy. On the basis of material collected in the Mediterranean, Atlantic and Pacifie Oceans sin ce 1964 this paper re-diagnoses the known 4 genera and 7 species (Nemertoderma bathycola Steinbiick, 1930-31 ; N. westbladi Steinbiick, 1938; N. psammicola Sterrer, 1970 (syn. N. rubra Faubel, 1976); Meara stichopi Westblad, 1949; Meara sp. (see SMITH et al., 1994); Nemertinoides elongatus Riser, 1987 ; and Flagellophora apelti Fau bel & Diirjes, 1978), describes one new genus with 2 new species (Ascoparia neglecta n. g., n. sp. and A. secunda n. sp.), and pro­ vides observations from living material on morphological variability, body size vs . reproductive state, statocyst structure and statolith variability, and sperm morphology and dimorphism. The paper concludes with diagnoses for the known taxa of Nemertodermatida, including the new family Ascopariidae. Key words: Platyhelminthes, free-living, marine; systematics, new species. INTRODUCTION ln 1930-31 Otto STEfNBOCK described Nemertoderma bathycola from a single tiny worm whicb he and Erich Reisinger bad dredged from a muddy bottom, at 300-400 rn depth, off Greenland. Nemertoderma caused a small sensation, not only because Steinbock, a meticulous observer, was also an assertive character (who liked to express himself double-spaced, with exclamation marks added) but because Nemertoderma was indeed unusual.
    [Show full text]
  • Frontiers in Zoology Biomed Central
    Frontiers in Zoology BioMed Central Research Open Access Myogenesis in the basal bilaterian Symsagittifera roscoffensis (Acoela) Henrike Semmler*1, Xavier Bailly2 and Andreas Wanninger1 Address: 1University of Copenhagen, Department of Biology, Research Group for Comparative Zoology, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark and 2Station Station Biologique de Roscoff, Place Georges Teissier BP74, F-29682 Roscoff Cedex, France Email: Henrike Semmler* - [email protected]; Xavier Bailly - [email protected]; Andreas Wanninger - [email protected] * Corresponding author Published: 19 September 2008 Received: 5 May 2008 Accepted: 19 September 2008 Frontiers in Zoology 2008, 5:14 doi:10.1186/1742-9994-5-14 This article is available from: http://www.frontiersinzoology.com/content/5/1/14 © 2008 Semmler 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: In order to increase the weak database concerning the organogenesis of Acoela – a clade regarded by many as the earliest extant offshoot of Bilateria and thus of particular interest for studies concerning the evolution of animal bodyplans – we analyzed the development of the musculature of Symsagittifera roscoffensis using F-actin labelling, confocal laserscanning microscopy, and 3D reconstruction software. Results: At 40% of development between egg deposition and hatching short subepidermal fibres form. Muscle fibre development in the anterior body half precedes myogenesis in the posterior half. At 42% of development a grid of outer circular and inner longitudinal muscles is present in the bodywall.
    [Show full text]
  • Marine-Flatworms-Of-The-Tropical-Indo-Pacific-Look
    Marine Flatworms of the Tropical Indo-Pacific Photographic guide on marine polyclads with 580+ species Andrey Ryanskiy PICTORIAL INDEX TO POLYCLAD FAMILIES AND GENERA PSEUDOCEROTIDAE: ACANTHOZOON - 9 THYSANOZOON - 14 BULACEROS - 16 MAIAZOON - 17 NYMPHOZOON - 17 PHRIKOCEROS - 18 PSEUDOBICEROS - 21 PSEUDOCEROS - 38 EURYLEPTIDAE: CYCLOPORUS - 86 EURYLEPTA - 92 EURYLEPTID - 101 STYLOSTOMUM - 101 DIPOSTHIDAE: PROSTHIOSTOMIDAE: MARITIGRELLA - 102 PROSTHECERAEUS - 105 PERICELIS - 106 ENCHIRIDIUM - 107 CESTOPLANIDAE: BONINIIDAE: LURYMARE - 107 PROSTHIOSTOMUM - 112 CESTOPLANA - 112 BONINIA - 113 PLANOCERIDAE: CALLIOPLANIDAE: PARAPLANOCERA - 115 PLANOCERA - 120 CALLIOPLANA - 121 HOPLOPLANIDAE - 122 STYLOCHIDAE: GNESIOCEROTIDAE: LIMNOSTYLOCHIDAE - 122 ILYELLA - 123 STYLOCHID - 123 ECHINOPLANA - 126 NOTOPLANIDAE: UNIDENTIFIED ACOTYLEANS3 GNESIOCEROS - 126 NOTOPLANA - 127 LEPTOPLANIDAE - 128 - 129 FLATWORMS: BASIC KNOWLEDGE Why are they flat? Polyclads are considered the most primitive bilaterally symmetrical animals (left side mirrors the right). They evolved from hydra-like animals about 550 million years ago. Flatworms have no body cavity other than the gut. Respiratory and blood vessel systems are completely missing and diffusion is used for transport of oxygen inside the body. This constrains flatworms to be flat as possible for maintaining metabolism, since no cell can be too far from the outside, making a flattened body shape necessary. How do they eat? Flatworms/Polyclads have a mouth with pharynx inside: a muscular tube through which the flatworm can suck food. Pharynx may be tubular or ruffled with numerous folds (more details on External Morphology Basics pages) Flatworms are carnivorous, feeding on small invertebrates, suctioning entirely their prey or digesting a part of it. Many species of the Pseudocerotidae family prefer ascidians, sponges, and bryozoans. For feeding, the pharynx protrudes and can be expanded into the individual zooids of colonial ascidians.
    [Show full text]
  • Acoela, Acoelomorpha) from British Waters
    Arxius de Miscel·lània Zoològica, 11 (2013): 153–157 ISSN:Vila–Farré 1698– et0476 al. First record of Oligochoerus limnophilus (Acoela, Acoelomorpha) from British waters M. Vila–Farré, M. Álvarez–Presas & J. G. Achatz Vila–Farré, M., Álvarez–Presas, M. & Achatz, J. G., 2013. First record of Oligochoerus limnophilus (Acoela, Acoelomorpha) from British waters. Arxius de Miscel·lània Zoològica, 11: 153–157, Doi: https://doi.org/10.32800/amz.2013.11.0153 Abstract First record of Oligochoerus limnophilus (Acoela, Acoelomorpha) from British waters.— We report the occurrence of the acoel Oligochoerus limnophilus (Acoelomorpha) from the British Islands, based on specimens captured in the river Thames (locally known as the river Isis) in Oxford, England, thereby considerably widening the distributional range of the species that had formerly been reported only from continental Europe. We further present live images and CLSM–projections of systematically informative structures that corroborate a close relationship with the genus Convoluta Ørsted, 1843. Key words: Acoela, Oligochoerus, Limnic, Thames. Resumen Primera cita de Oligochoerus limnophilus (Acoela, Acoelomorpha) en aguas británicas.— Informamos de la existencia de poblaciones del acelo Oligochoerus limnophilus (Acoelo- morpha) en las islas Birtánicas, basándonos en los especímenes capturados en el río Támesis (también conocido localmente como río Isis) a su paso por Oxford, Inglaterra, ampliando así considerablemente el área de distribución de la especie, restringida hasta ahora al continente europeo. La información gráfca que aportamos, imágenes de especí- menes vivos y proyecciones CLSM de estructuras seleccionadas por su valor sistemático, corrobora su estrecha relación con los miembros del género Convoluta Ørsted, 1843. Palabras clave: Acoela, Oligochoerus, Límnico, Támesis.
    [Show full text]
  • 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.
    [Show full text]