105 research outputs found

    First record of the sea anemone Metridium senile from South Africa

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    A sea anemone new to the South African fauna is reported from Table Bay Harbour and is identified as Metridium senile. The population was probably introduced from Europe and although well established, appears to be restricted to the harbour area

    Feeding Behavior of Spurilla sp. (Mollusca: Opisthobranchia) with a Description of the Kleptocnidae Sequestered from Its Sea Anemone Prey

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    Feeding behavior of Spurilla sp. (Mollusca: Opisthobranchia) with a description of the kleptocnidae sequestered from its sea anemone prey. Zoological Studies 51(7): 905-912. Cnidocysts are sequestered from cnidarian prey by aeolid nudibranchs and stored in the tips of their appendages (cerata). The kleptocnidae of 11 specimens of Spurilla sp. are described in detail. The types and relative abundances of prey cnidocysts in nudibranch cerata were highly variable, suggesting exclusive anemone consumption. Spirocysts and several types of microbasic p-mastigophores, microbasic b-mastigophores, and basitrichs were found in external and internal tissues of sea anemone prey. This is the 1st report of predation of aeolid Spurilla sp. on the sea anemones Antholoba achates, Metridium senile lobatum, and Parabunodactis imperfecta from the rocky intertidal of Patagonia (Chubut Province, Argentina) and on Anthothoe chilensis and Tricnidactis errans at Mar del Plata (Buenos Aires Province, Argentina). Photographs and digital videos of aeolidacean feeding behavior were recorded in situ and in aquaria. The purpose of this study was to provide valuable information on the diet of Spurilla sp. from Argentina using field observations and descriptions of the kleptocnidae.Fil: Garese, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: García Matucheski, Stella. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. San Martín; ArgentinaFil: Muniain, Claudia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Acuña, Fabian Horacio. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Two species of Diadumene (Cnidaria, Actiniaria).

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    45 pages : illustrations (some color), color map ; 26 cm.Diadumenidae is a monogeneric family comprised of 10 valid species in the genus Diadumene. Although these species are distributed in all but the Southern Ocean, Diadumene lineata is a cosmopolitan species and one of the most widely distributed marine organisms. Recent phylogenetic analyses with multiple species have recovered Diadumenidae as a monophyletic group with high support. Although generic placement is straightforward, species-level identifications within Diadumene are difficult because species are defined by a mosaic of characters that vary in degree rather than kind. Two species of the genus have been recorded in the southwestern Atlantic: D. paranaensis along the south coast of Brazil and D. lineata along the southeast and northeast coasts of Brazil as well as in Argentina. Here we record D. leucolena for the first time in the southern hemisphere and describe D. manezinha, sp. nov., raising to four the number of species of Diadumene for Brazil and to 11 worldwide. We incorporated microcomputed tomography (micro-CT) into the description of both species in the first application of the method for Actiniaria. We evaluate the utility of micro-CT imaging and its potential to generate fast, low-cost, and high-resolution datasets despite the anemone's low-density soft tissue. We present a protocol for sample handling, chemical staining, and scanning parameters that resulted in satisfactory imaging of the two specimens examined. We also analyze advantages and limitations of using micro-CT over traditional techniques in the study of sea anemones

    Environmental Dimensions of the RMS Leinster Sinking

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    The Irish Sea which separates Great Britain and Ireland has often been written about in terms of divisions, threats, and hazards. Facing each other across that sea, the coast of Wales and Ireland’s eastern seaboard have a more complex story to tell, one characterised by intimate if troubled lines of connection. A place of passage for centuries, the Irish Sea has a distinct identity, its memory longer and more capacious than borders or polities. The region ties together port communities that differ in their stories, cultures, and worldviews. This article explores themes of division and connection across coasts through the story of the Royal Mail Ship (RMS) Leinster, a British mail steamer that was torpedoed just off the coast of Ireland as World War I neared its end and the Irish War of Independence began to stir

    Mitochondrial Group I Introns in Hexacorals Are Regulatory Genetic Elements

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    Hexacoral mitochondrial genomes are highly economically organized and vertebrate-like in size, structure, and gene content. A hallmark, however, is the presence of group I introns interrupting essential oxidative phosphorylation (OxPhos) genes. Two genes, encoding NADH dehydrogenase subunit 5 (ND5) and cytochrome c oxidase subunit I (COI), are interrupted with introns. The ND5 intron, located at position 717, is obligatory in all hexacoral specimens investigated. The ND5-717 intron is a giant-sized intron that carries several canonical OxPhos genes. Different modes of splicing appear to apply for the ND5-717 intron, including conventional cis-splicing, backsplicing, and trans-splicing. Three distinct versions of hexacoral COI introns are noted at genic positions 884, 867, and 720. The COI introns are of the mobile-type, carrying homing endonuclease genes (HEGs). Some COI-884 intron HEGs are highly expressed as in-frame COI exon fusions, while the expression of COI-867 intron HEGs appear repressed. We discuss biological roles of hexacoral mitochondrial ND5 and COI introns and suggest that the ND5-717 intron has gained new regulatory functions beyond self-splicing
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