91 resultados para BRYOZOANS


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The encrustation of Paleozoic rhynchonelliform brachiopods has been studied for decades, but modern brachiopods have not received similar scrutiny. The discovery of abundant subtropical brachiopods from the Southeast Brazilian Bight provides an unprecedented opportunity to assess epibiont abundance, diversity, and encrustation patterns in modern brachiopod assemblages. Across the outer shelf, encrustation frequencies vary among taxa, from mean values of 0.45% for Platidia to 9.3% for Argyrotheca. Encrustation frequencies for Bouchardia increase from 1.6% on the outer shelf to 84% on the inner shelf Larger valves are encrusted more frequently, and epibionts preferentially colonize valve interiors. Increased encrustation on the inner shelf may reflect the greater surface area of larger hosts, longer exposure of dead shells, water-mass characteristics, sedimentation rates, productivity, or other factors that vary with depth. Inner-shelf brachiopods exhibit encrustation frequencies comparable to those reported for epifaunal bivalves. The epibiont fauna is dominated by bryozoans and serpulids, with minor roles played by spirorbids, bivalves, barnacles, foraminifera, algae, and other taxa. Epibiont abundance at each site is highly variable, but sites are similar in rank importance of epibiont taxa. A different suite of epibionts colonized Paleozoic brachiopods, but similar patterns of encrustation have been observed, including preferential settlement according to valve morphology. These results provide a baseline for evaluating the encrustation of modern bivalves and ancient brachiopods, and may elucidate the macroevolutionary history of epibionts and their relationship to their hosts.

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The external infestation of Callinectes ornatus Ordway, 1863 and Callinectes danae Smith, 1869, in particular cirripeds, was studied for two consecutive years in the Ubatuba Bay (SP) (23 degrees 26' S and 45 degrees 02' W). Bryozoans, polychaetes and cirripeds were found on both swimming crab species, but cirripeds were the most abundant and frequent. The number of infested swimming crabs increased proportionally to carapace size, but not surpassing 30 %, suggesting an absence of terminal anecdysis in both species. The establishment of the pernicious organisms on their hosts is influenced by other factors, such as their habit of burying themselves in sediments. The correlation between molting activity in adult specimens of both sexes and the low incidence of epizoonts suggest that C. ornatus and C. danae may be molting after maturity.

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Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR

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Registros sedimentares do Neocarbonífero, particularmente do Moscoviano, na Bacia do Amazonas, Norte do Brasil, caracterizam a zona de contato entre as formações Monte Alegre (rochas siliciclásticas) e Itaituba (rochas carbonáticas). A análise faciológica da sucessão Moscoviana de até 40 m de espessura, exposta na região de Monte Alegre e Itaituba, Estado do Pará, permitiu identificar 5 associações de fácies (AF), que correspondem a depósitos estabelecidos no ambiente costeiro, representados por dunas/intedunas eólicas (AF1), lençóis de areia/wadi (AF2), laguna/washover (AF3), praia/planície de maré (AF4) e laguna/delta de maré (AF5). A associação de campo de dunas/interdunas (AF1) é constituída por arenitos finos a médios, bimodais com estratificação cruzada de médio porte, laminação cavalgante transladante subcrítica e arenitos com gradação inversa. Arenitos finos com acamamento maciço, marcas de raízes e, subordinadamente, verrugas de aderência (adhesion warts), ocorrem nos limites dos sets de estratificação cruzada e indicam, respectivamente, paleossolos e migração de grãos por ação eólica sobre interduna úmida. Depósitos de lençóis de areia/wadi (AF2) são compostos de arenitos finos a médios com estratificação plano-paralela e laminação cavalgante transladante subcrítica, relacionados a superfícies de deflação (lençóis de areia), enquanto arenitos finos a médios com estratificações cruzadas tangencial e recumbente, e acamamento convoluto, caracterizam rios efêmeros com alta energia. Pelitos laminados e arenitos finos com laminação cruzada cavalgante, contendo o icnofóssil Palaeophycus, representam sedimentação em ambiente de baixa energia e foram agrupados na associação de laguna/washover (AF3). Os depósitos de praia/planície de maré (AF4) consistem em arenitos finos a médios, com estratificação plano-paralela a cruzada de baixo ângulo, intercalados com lentes de dolomito fino maciço, localmente truncados por arenitos finos a médios. Estas fácies foram formadas pelo fluxo-refluxo em ambiente de praia, localmente retrabalhadas por pequenos canais, enquanto o carbonato é interpretado como precipitado em poças (ponds). Na AF4 encontram-se também pelitos laminados com gretas de contração, lâminas curvadas de argila e arenitos com estratificação cruzada tabular de pequeno a médio porte, contendo filmes de argila sobre foresets e superfícies de reativação, sugerindo a migração de sandwaves na intermaré. A associação de laguna/delta de maré (AF5) é constituída por calcários dolomitizados (mudstones, wackestones, packstones e grainstones) com poros do tipo vug e móldicos e bioclastos de braquiópodes, equinodermas, foraminíferos, ostracodes, briozoários, trilobitas, moluscos e coral isolado não fragmentado, além do ichnofóssil Thalassinoides. Conglomerados com seixos de calcário dolomitizado, arenitos finos com estratificação cruzada de baixo ângulo e superfícies de reativação, localmente sobrepostos por arenitos finos com estratificação cruzada sigmoidal e laminação cruzada cavalgante, foram interpretados como depósitos de tidal inlet e delta de maré. As associações de fácies/microfácies e os dados paleontológicos descritos neste trabalho corroboram a predominância de ambientes lagunares, em parte, conectados a um ambiente desértico costeiro para o intervalo de transição entre as formações Monte Alegre e Itaituba. A abundância de grãos arredondados de areia fina nas fácies carbonáticas corrobora influxo siliciclástico advindo do ambiente desértico adjacente ao ambiente costeiro. Condições mais quentes e tropicais para a sucessão estudada são também indicadas pela presença de carbonatos e argilominerais como illita e, principalmente, esmectita, bem como uma fauna diversificada. Os litotipos siliciclásticos e carbonáticos intercalados que caracterizam a fase final da deposição Monte Alegre e o início da sedimentação Itaituba, justificam sua representação em um mesmo sistema deposicional costeiro.

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O presente trabalho compreende o estudo geológico e paleontológico detalhado da litofácies recifal da Formação Pirabas, Estado do Pará, aflorante na Praia do Maçarico, município de Salinópolis, como um corpo pequeno, isolado e lenticular, que deve ter se desenvolvido na rampa interna da plataforma do Mar de Pirabas. O conteúdo biótico é rico e variado, composto por três grupos de algas coralíneas, poríferos, corais, briozoários, equinoides, foraminíferos, ostracodes, e moluscos. Foram reconhecidos neste recife em mancha três estágios de sucessão ecológica, estabilização, colonização e diversificação, onde as finas crostas micríticas reconhecidas na parte superior do estágio diversificação indicam degradação das condições ambientais favoráveis à acreção recifal, provavelmente devido a continentalização do sítio deposicional. O exame petrográfico revelou apenas uma microfácies deposicional, biomicrito, sem consideráveis variações texturais e composicionais. A cimentação marinha é predominante, representada por massas microcristalinas e cimentos micríticos, localmente neomorfisados para bioesparito, e detritos carbonáticos advindos do fluxo biogênico inconsolidado, resultantes principalmente da dispersão de cristais de aragonita dos fragmentos algálicos, acumulados sob a forma de lama micrítica. Para a gênese da bioconstrução as algas foram fundamentais na consolidação e modelagem do arcabouço, principalmente as macroalgas vermelhas, decisivas para a proteção e cimentação dos demais organismos.

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Este trabalho trata sobre a identificação dos eventos biológicos globais, regionais e locais da Formação Pirabas, sob a luz dos modernos conceitos de análise e evolução geobiológica de bacias sedimentares, integrando os processos geológicos crustais do Neógeno com as respostas adaptativas e filogenéticas das biotas marinhas. Foram caracterizados bioeventos globais de inovação e radiação entre os moluscos e sirênios e,bioeventos regionais de radiação e dispersão biogeográfica de biválvios, gastrópodes, crustáceos decápodes, equinóides, corais escleractíneos, briozoários, ostracodes e foraminíferos, assim como de extinção da espécie Orthaulax pugnax. Também foram reconhecidos bioeventos locais de expansão biogeográfica da flórula, de uma comunidade estenobiôntica, bem como variações ecofenotípicas nas espécies também registradas nas demais áreas da Província Biogeográfica Caribeana.

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This paper includes a reassessment of Scrupocellaria reptans (Linnaeus, 1758) (basionym Sertularia reptans), the lectotype of which is selected and figured from among herbarium-sheet specimens held at the Linnean Society of London. Material previously assigned to S. reptans was examined, providing morphological characteristics to distinguish Scrupocellaria ellisi n. sp. Scrupocellaria reptans has a geographically limited distribution in the United Kingdom, while S. ellisi is more widespread in the North Sea, Northeast Atlantic, Adriatic and Tasmania.

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Background: Bugula is a speciose genus of marine bryozoans, represented by both endemic and cosmopolitan species distributed in tropical and temperate waters and important to marine biologists because of the occurrence of many species in harbor and fouling communities, therefore as potential invaders. The southeastern Brazilian coast in the southern Atlantic hosts the highest known diversity of the genus, a status intimately associated with the intensity of collecting efforts. Methodology: Morphological data based on the examination of living specimens, scanning electron and light microscopic images, and morphometric analyses were used to assess the diversity of Bugula along the coastal areas of southern, northeastern, and southeastern Brazil. In this study, morphological species boundaries were based mainly on avicularian characters. For two morphologically very similar species, boundaries are partially supported by 16 S rDNA molecular data. Results: Nine species are newly described from Brazil, as follows: Bugula bowiei n. sp. (= Bugula turrita sensu Marcus, 1937) from the southern, northeastern, and southeastern coasts; Bugula foliolata n. sp. (= Bugula flabellata sensu Marcus, 1938), Bugula guara n. sp., Bugula biota n. sp. and Bugula ingens n. sp from the southeastern coast; Bugula gnoma n. sp. and Bugula alba n. sp. from the northeastern coast; Bugula rochae n. sp. (= Bugula uniserialis sensu Marcus, 1937) from the southern coast; and Bugula migottoi n. sp., from the southeastern and southern coasts. Conclusion: The results contribute to the morphological characterization and the knowledge of the species richness of the genus in the southwestern Atlantic (i.e., Brazil), through the description of new species in poorly sampled areas and also on the southeastern coast of that country. Additionally, the taxonomic status of the Brazilian specimens attributed to B. flabellata, B. turrita and B. uniserialis are clarified by detailed studies on zooidal and avicularia morphology.

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Among the marine invertebrate groups recorded from oceanic islands, bryozoans stand out because they can live and reproduce in suboptimal habitats, which may enhance their dispersal capabilities. This study aimed to update the checklist of bryozoans known from the Saint Peter and Saint Paul Archipelago (ASPSP) and discusses their distribution. During the five expeditions conducted between 2007 and 2009, 22 species were found, of which 16 were new occurrences for the archipelago. The bryozoans were collected from different biotic (algae and invertebrates) and abiotic (rocks, rubble and wrecks) substrata. The bryozoan community in ASPSP includes: eight new and probably endemic species, five species that belong to widespread species complexes, three species known only from the Brazilian coast, two species reported from the Western Atlantic and one species recorded from oceanic islets in the Atlantic. Additionally, three species are widespread in tropical to subtropical waters. Margaretta buski can be highlighted as the most conspicuous and abundant species between 1045 m deep and acts as an "ecosystem engineer".

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Despite implausible cosmopolitanism, the species Scorpiodinipora costulata (Canu & Bassler, 1929) has been attributed with reservations to small encrusting colonies with similar morphological features whose known distribution is scattered in tropical and subtropical seas: Pacific Ocean (Philippines), Indian Ocean (Oman), Red Sea, SE Mediterranean, SE Atlantic (Ghana) and SW Atlantic (Brazil). This material raised questions about its generic assignment. The genus Scorpiodinipora Balavoine, 1959 is redescribed with Schizoporella costulata Canu & Bassler, 1929, from the Philippines as the type species, as Balavoine misidentified the specimens to define the genus as Cellepora bernardii Audouin, 1826. Moreover, SEM examination of the cotypes of S. costulata showed that Canu & Bassler confused two genera among them. A lectotype and paralectorype were thus chosen from Canu & Bassler's syntypes corresponding with the present morphotype. Hippodiplosia ottomuelleriana var. parva Marcus, 1938, from Brazil, which presents the same morphotype, is provisionally considered as the junior synonym of S. costulata. Considering the broad allopatric distribution of this morphotype across the oceans and the low capacity of dispersal of species with short-lived larvae, it is likely that this material includes several sibling species. However, the role of man-mediated dispersal is not excluded, at least in regions with high shipping activity, such as that comprising the Suez Canal.

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The chemical investigation of the MeOH extract from the bryozoan B. dentata MeOH yielded tambjamines A (1), C (3), D (4), K (6), aldehyde 8 and the new tambjamine J1(9), while the extract of its predator, the nudibranch Tambja stegosauriformis, yielded tambjamines C and K, along with aldehyde 8. Furodisinin lactone (11) was isolated from the nudibranch Hypselodoris lajensis, a compound previously isolated from Dysidea sponges. The alkaloid 2,5,6-tribromo-N-methylgramine (12) was isolated from the nudibranch Okenia zoobotryon and from its prey, the bryozoan Zoobotryon verticillatum, the only source of 12 previously known.

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Die neogene Lagos-Portimão Formation (Unter- bis Mittelmiozän) bildet einen Teil der Steilküste der Algarve (S-Portugal) und besteht aus einer zyklischen Wechsellagerung von Karbonaten und Sand-steinen. Die vorliegende Arbeit bietet ein Modell zur sedimentologischen, faziellen und stratigraphischen Entwicklung dieser Einheit an. Basierend auf Profilen entlang der gesamten lateralen Erstreckung der Einheit wurden verschiedene Gelände- und Labormethoden angewandt, um ein Modell entwickeln zu können. Messungen des Sr87/86-Isotopenverhältnisses sollten Klarheit bezüglich der stratigraphischen Position bringen. Die laterale Korrelation der Profile erfolgte über lithologische und fazielle Ansprachen. Unterstützend wurden einzelne Profile mit einem tragbaren Gammaray-Spektrometer gemessen. Es wurden vier Leithorizonte etabliert, die sich durch fazielle Merkmale und spezielle Fossilführung defi-nieren lassen. Die Mikrofazies wurde qualitativ und quantitativ analysiert. Als statistisches Verfahren wurde unter anderem eine hierarchische Clusteranalyse durchgeführt, über welche fünf Biofaziestypen des warm-temperierten Klimabereichs unterschieden werden. Die Fossilführung wird von Mollusken, Bryozoen und Rotalgen dominiert. Ausnahmen bilden stratigraphisch isolierte Vorkommen von kolo-nialen Korallen, die jedoch keine Riffkörper aufbauen. Die Ergebnisse aller zuvor erwähnten Untersuchungen deuten auf Ablagerungen eines nicht-tropischen Hochenergie-Schelfs hin. Sedimentäre Zyklen sind oftmals unvollständig, es treten Hartgründe und Auf-arbeitungs- bzw- Kondesationshorizonte auf. Die geochemische Altersdatierung weist Alterssprünge und -inversionen auf. Ein Vergleich mit dem SW-australischen Schelf und dem von James et al. (1994) eingeführten Modell des shaved shelf bietet sich aufgrund der Ähnlichkeit der Sedimentgesteine und des ozeanographischen Settings an. Weiterhin werden zeitgleiche bzw. faziell ähnliche Becken vergleichend diskutiert. Das Sedimentationsgeschehen der Lagos-Portimão Formation wird maßgeblich durch eine halokinetisch bedingte unregelmäßige Subsidenz und Hebung beeinflußt. Der Salzdom von Albufeira war während der Sedimentation der Einheit mehrfach in Bewegung. Rutschungspakete, Entlastungsspalten und Sanddikes zeugen davon. Die sequenzstratigraphische Interpretation bietet einen neuen Ansatz, in dem sie von Hochstand-Sandsteinen und Tiefstand-Karbonaten ausgeht.

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P>1. Proliferative kidney disease (PKD) is a disease of salmonid fish caused by the endoparasitic myxozoan, Tetracapsuloides bryosalmonae, which uses freshwater bryozoans as primary hosts. Clinical PKD is characterised by a temperature-dependent proliferative and inflammatory response to parasite stages in the kidney.;2. Evidence that PKD is an emerging disease includes outbreaks in new regions, declines in Swiss brown trout populations and the adoption of expensive practices by fish farms to reduce heavy losses. Disease-related mortality in wild fish populations is almost certainly underestimated because of e.g. oversight, scavenging by wild animals, misdiagnosis and fish stocking.;3. PKD prevalences are spatially and temporally variable, range from 0 to 90-100% and are typically highest in juvenile fish.;4. Laboratory and field studies demonstrate that (i) increasing temperatures enhance disease prevalence, severity and distribution and PKD-related mortality; (ii) eutrophication may promote outbreaks. Both bryozoans and T. bryosalmonae stages in bryozoans undergo temperature- and nutrient-driven proliferation.;5. Tetracapsuloides bryosalmonae is likely to achieve persistent infection of highly clonal bryozoan hosts through vertical transmission, low virulence and host condition-dependent cycling between covert and overt infections. Exploitation of fish hosts entails massive proliferation and spore production by stages that escape the immune response. Many aspects of the parasite's life cycle remain obscure. If infectious stages are produced in all hosts then the complex life cycle includes multiple transmission routes.;6. Patterns of disease outbreaks suggest that background, subclinical infections exist under normal environmental conditions. When conditions change, outbreaks may then occur in regions where infection was hitherto unsuspected.;7. Environmental change is likely to cause PKD outbreaks in more northerly regions as warmer temperatures promote disease development, enhance bryozoan biomass and increase spore production, but may also reduce the geographical range of this unique multihost-parasite system. Coevolutionary dynamics resulting from host-parasite interactions that maximise fitness in previous environments may pose problems for sustainability, particularly in view of extensive declines in salmonid populations and degradation of many freshwater habitats.

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Taxon-specific stable carbon isotope (δ13C) analysis of chitinous remains of invertebrates can provide valuable information about the carbon sources used by invertebrates living in specific habitats of lake ecosystems (for example, sediments, water column, or aquatic vegetation). This is complementary to δ13C of sedimentary organic matter (SOM), which provides an integrated signal of organic matter produced in a lake and its catchment, and of diagenetic processes within sediments. In a sediment record from Strandsjön (Sweden) covering the past circa 140 years, we analyzed SOM geochemistry (δ13C, C:Natomic, organic carbon content) and δ13C of chitinous invertebrate remains in order to examine whether taxon-specific δ13C records could be developed for different invertebrate groups and whether these analyses provide insights into past changes of organic carbon sources for lacustrine invertebrates available in benthic and planktonic compartments of the lake. Invertebrate taxa included benthic chironomids (Chironomus, Chironomini excluding Chironomus, Tanytarsini, and Tanypodinae), filter-feeders on suspended particulate organic matter (Daphnia, Plumatella and Cristatella mucedo), and Rhabdocoela. δ13C of chironomid remains indicated periodic availability of 13C-depleted carbon sources in the benthic environment of the lake as δ13C values of the different chironomid taxa fluctuated simultaneously between -34.7 and -30.5‰ (VPDB). Daphnia and Bryozoa showed parallel changes in their δ13C values which did not coincide with variations in δ13C of chironomids, though, and a 2-3‰ decrease since circa AD 1960. The decrease in δ13C of Daphnia and Bryozoa could indicate a decrease in phytoplankton δ13C as a result of lower lake productivity, which is in accordance with historical information about the lake that suggests a shift to less eutrophic conditions after AD 1960. In contrast, Rhabdocoela cocoons were characterized by relatively high δ13C values (-30.4 to -28.2‰) that did not show a strong temporal trend, which could be related to the predatory feeding mode and wide prey spectrum of this organism group. The taxon-specific δ13C analyses of invertebrate remains indicated that different carbon sources were available for the benthic chironomid larvae than for the filter-feeding Daphnia and bryozoans. Our results therefore demonstrate that taxon-specific analysis of δ13C of organic invertebrate remains can provide complementary information to measurements on bulk SOM and that δ13C of invertebrate remains may allow the reconstruction of past changes in carbon sources and their δ13C in different habitats of lake ecosystems.

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We explored the extent to which δ13C and δD values of freshwater bryozoan statoblasts can provide information about the isotopic composition of zooids, bryozoan food and surrounding water. Bryozoan samples were collected from 23 sites and encompassed ranges of nearly 30‰ for δ13C and 100‰ for δD values. δ13C offsets between zooids and statoblasts generally ranged from −3 to +4.5‰, with larger offsets observed in four samples. However, a laboratory study with Plumatella emarginata and Lophopus crystallinus demonstrated that, in controlled settings, zooids had only 0–1.2‰ higher δ13C values than statoblasts, and 1.7‰ higher values than their food. At our field sites, we observed a strong positive correlation between median δ13C values of zooids and median δ13C values of corresponding statoblasts. We also observed a positive correlation between median δD values of zooids and statoblasts for Plumatella, and a positive correlation between median δD values of statoblasts and δD values of lake water for Plumatella and when all bryozoan taxa were examined together. Our results suggest that isotope measurements on statoblasts collected from flotsam or sediment samples can provide information on the feeding ecology of bryozoans and the H isotopic composition of lake water.