563 resultados para Harpacticoida
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A new genus of Parastenocarididae is described from the Neotropical region. Iticocaris gen. nov. is established to include Parastenocaris itica Noodt, 1962. Iticocaris gen. nov. is defined by the following characters: 1) male leg 3 with 2-segmented exopod; 2) first exopodal segment short and rectangular; 3) thumb hypertrophic, longer than the second exopodal segment and inserted on the distal edge of exopod segment 1, occupying the whole distal margin; 4) exopod 2 or apophysis strongly sclerotized, articulated with the exopod segment 1 on its inner margin and curved against the thumb, forming a strong forceps; 5) leg 4 endopod without dimorphism in shape and size vs. minor dimorphism in ornamentation; 6) leg 5 with three setae and 7) lack of the anterolateral furcal seta II. The new genus is monotypic, represented by Iticocaris itica (Noodt, 1962) comb. nov., from El Salvador, Central America. A close relationship is hypothesized between I. itica and the genus Brasilibathynellocaris Jakobi, 1972, the males of which both share the forceps-like elongated apophysis.
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Both sexes of a new genus and species of Ectinosomatidae (Copepoda, Harpacticoida) from sublittoral sediments collected on the inner continental shelf in Ubatuba, Sao Paulo State (Brazil) are described in detail. Chaulionyx gen. n. (type species: C. paivacarvalhoi sp. n.) differs from all known genera in the presence of a conspicuous bifid spine on the prehensile P1 endopod. It can be differentiated from other genera with a prehensile endopod (Halophytophilus Brian, 1919; Bradyellopsis Brian, 1925; Klieosoma Hicks & Schriever, 1985) by the presence of distinctive subrectangular middorsal pores on the urosomites and the unarmed male sixth legs. The genus Lineosoma Wells, 1965 is recognized as a paraphyletic taxon and relegated to a junior subjective synonym of Noodtiella Wells, 1965. Arenosetella pectinata Chappuis, 1954a is removed from its floating position in Ectinosomoides Nicholls, 1945, transferred to the genus Noodtiella as N. pectinata comb. n. and considered the senior subjective synonym of N. toukae Mitwally & Montagna, 2001. Dichotomous keys are provided for the identification of the 18 valid species of Noodtiella and the 21 valid genera of the family Ectinosomatidae. Halophytophilus aberrans Wells & Rao, 1987 is placed species incertae sedis in the family.
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Both sexes of a new species of Noodtorthopsyllus Lang, 1965 (Harpacticoida, Cristacoxidae) from a sandy beach in Sao Paulo State (Brazil) are described using light and scanning electron microscopy. Noodtorthopsyllus tageae sp. nov. displays a mosaic of characters drawn from both Noodtorthopsyllus and Cristacoxa Huys, 1990, blurring the boundaries between both genera. Consequently, Cristacoxa, the type genus of the nominal family-group taxon Cristacoxidae Huys, 1990, is relegated to a junior subjective synonym of Noodtorthopsyllus, and its type species is transferred to the latter as N. petkovskii (Huys, 1990) comb. nov. A new genus Acuticoxa is proposed to accommodate A. ubatubaensis sp. nov. (type species), collected on the northern continental shelf of Sao Paulo State, and A. biarticulata sp. nov., previously identified as Laophontisochra sp., from the Northern Magellan Straits. Amended diagnoses are provided for Noodtorthopsyllus and Laophontisochra. Autapomorphies supporting the monophyly of the Cristacoxidae are re-evaluated, including new data on P3 endopod sexual dimorphism and caudal ramus development. It is concluded that a recently published hypothesis of a deeply rooted split of the family into two highly divergent lineages cannot be supported. Consequently, both Laophontisochra and Acuticoxa gen. nov. are removed from the Cristacoxidae and tentatively assigned to the Nannopodidae (ex Huntemanniidae), forming a clade with three other genera displaying coxal modifications on leg 1 (Rosacletodes Wells, 1985; Huntemannia Poppe, 1884; and an as yet undescribed genus from Brazil). Based on the sexual dimorphism of the P4 endopod, we propose to transfer Metahuntemannia Smirnov, 1946 and Pottekia Huys, 2009 from the Nannopodidae to the Canthocamptidae (subfamily Hemimesochrinae) where they are probably most closely related to Psammocamptus Mielke, 1975; Bathycamptus Huys & Thistle, 1989; Perucamptus Huys & Thistle, 1989; and Isthmiocaris George & Schminke, 2003. An identification key to the genera of the Nannopodidae is presented.
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A new genus and species of Normanellidae (Copepoda, Harpacticoida), Paranaiara inajae gen. et sp. nov., is described from the continental shelf off the northern coast of Sao Paulo State, Brazil. The new genus differs from the type genus Normanella Brady, 1880 and Sagamiella Lee & Huys, 1999 in its presence of lamelliform caudal rami, a maxillulary endopod represented by 2 setae, an unarmed maxillipedal syncoxa, and reduced setation on P2 enp-2 (without outer spine) and P3 enp-2 (with only 2 inner setae). All these apomorphic character states are shared with the genus Pseudocletodes Scott & Scott, 1893, formerly placed in the family Nannopodidae (ex Huntemanniidae) and here assigned to the Normanellidae. Pseudocletodes can be differentiated from Paranaiara by the loss of the P1 endopod and of the inner seta on P2-P4 enp-1, the presence of only 2 inner setae on P2 enp-2 (instead of 3) and only 1 inner seta on P4 exp-3 (instead of 2), the presence of a second inner seta on P4 enp-2 (instead of 1), the morphology of the fifth pair of legs which are not medially fused and have only 3 endopodal elements (instead of 4) in the male, and the well developed caudal ramus seta V (instead of rudimentary). It is postulated that prehensility of the P1 endopod was secondarily lost in the common ancestor of Paranaiara and Pseudocletodes. An updated family diagnosis of the Normanellidae and a dichotomous identification key to the 22 currently valid species are presented.
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Two expeditions, undertaken in 1994 and 1996, provided quantitatively sampled material of sublittoral and bathyal meiobenthos from the Paso Ancho of the Straits of Magellan, the Beagle Channel, and the Patagonian continental slope (Chile). To investigate whether these distinct geographic areas might also be characterised by different harpacticoid assemblages, qualitative and quantitative analyses of Copepoda Harpacticoida were carried out. At supraspecific level 25 harpacticoid families were found, as well as several species that could not yet be assigned to any major harpacticoid taxon. Due to the high amount of collected Harpacticoida, detailed investigations at species level had to be restricted to six taxa, namely the Ancorabolidae, Argestidae, Cletodidae, Diosaccinae, Paramesochridae, and Paranannopinae. The corresponding specimens were assigned to 122 species in 52 genera. More than 80% of them are new to science. Qualitative comparisons of both species composition and species distribution allow the three areas to be distinguished in terms of species richness. However, statistical analyses confirm these results only partly. Similarity analyses applying non-metrical multidimensional scaling, as well as diversity analyses using the rarefaction method, suggest that the observed differences in distribution and diversity patterns are due to small-scale, local conditions, which may overlay possible large-scale ones.
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Dependence of the faunal composition and species structure of the White Sea littoral Harpacticoida on sediment properties was studied. Three groups of species could be distinguished according to their relationship with sediment properties: (1) species typical of silty sediments, (2) species preferring sediments with high gravel content, and (3) species inhabiting well-sorted washed sands. Vertical distribution of crustaceans within sediments of different types was studied. Vertical migrations of harpacticoids (3) during the tidal cycle were described. Data on interannual variability of harpacticoid fauna are presented.
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v.5 Copepoda-Harpacticoida
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Este trabalho avalia a variabilidade espaço-temporal da meiofauna do médiolitoral na praia de Ajuruteua, Estado do Pará. As coletas foram realizadas a cada dois meses, entre abril de 2003 a fevereiro de 2004 durante as marés de sizígia, em diferentes zonas da praia. As amostras foram retiradas com um amostrador cilíndrico de 3,14 cm² e fixadas em formalina salina a 5%. Em laboratório, as amostras foram passadas em malha de 0,063 mm de abertura e os organismos retidos identificados em nível de grandes grupos taxonômicos, contados e fixados em álcool etílico a 70%. A meiofauna esteve representada por oito grupos: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, adultos de Copepoda Harpacticoida e juvenis de Copepoda Harpacticoida. Nematoda foi o grupo dominante, representando 74% do total de indivíduos, seguido de Copepoda (19%). Pôde-se observar clara zonação horizontal da fauna, que se distribuiu em três faixas paralelas à linha de praia, com características significativamente distintas quanto à abundância, riqueza e densidade dos principais grupos taxonômicos. No médiolitoral médio foram observados valores significativamente mais elevados de riqueza e abundância, enquanto os valores mais baixos foram registrados no médiolitoral superior e inferior. A comunidade de meiofauna, ainda que não tenha variado significativamente entre períodos climáticos, foi mais rica e abundante nos meses secos. Os principais fatores responsáveis pelas variações espaço-temporais da meiofauna foram a ação das ondas e das marés e as variações na salinidade da água.
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School of Industrial Fisheries, Cochin University of Science and Technology
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Poucos são os estudos realizados sobre zooplâncton em estuários na região Bragantina do Estado do Pará. Este trabalho foi realizado em um canal de maré, denominado de Furo do Chato, próximo a localidade de Ajuruteua. Município de Bragança, no litoral do Estado do Pará, e teve por objetivo estudar a composição qualitativa e quantitativa do zooplâncton, bem como as variações sazonais em função das variáveis ambientais, Durante o período de agosto/96 a janeiro/97 foram feitas oito campanhas a cada três semanas, com obtenção de amostras a cada duas horas, durante 24 horas. O Furo do Chato é um canal de maré com forte influência costeira. Assim, a maior parte dos representantes do zooplâncton encontrados são de origem costeira. Além de componentes holoplanctônicos e meroplanctônicos, as amostras de zooplâncton no Furo do Chato apresentaram representantes da fauna bentônica. Dez filos foram identificados: Protozoa, Mollusca, Chordata, Annelida, Cnidaria, Arthropoda, Urochordata, Chaetognatha, Nematoda e Bryozoa. A classe Copepoda teve maior representatividade, tanto pela densidade, pela biomassa como Oela freqüência de ocorrência nas amostras. As categorias mais abundantes e frequentes (>40%) foram Pseudodiaptomus marshi, Acartia iilljeborgi, A. tonsa, Harpacticoida, Sagitta sp., Oiko pleura dioica, Cnidaria, lsopoda, zoeas de caranguejo, pós-larvas de camarão e alevinos de peixes. A abundâncias médias foram baixas (1,07 indiv./m³e 16,43 mg/m³). A comunidade do zooplâncton é mais abundante nos meses de transição do que no período seco A maiores abundâncias ocorreram em geral à noite e durante as marés de sizígia. Contudo, o ciclo diário de marés, a salinidade e as fases lunares não influenciaram a variabilidade do zooplâncton como um todo, mas apenas em algumas categorias isoladamente.
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Este trabalho avalia a variabilidade espaço-temporal da meiofauna do médiolitoral na praia de Ajuruteua, Estado do Pará. As coletas foram realizadas a cada dois meses, entre abril de 2003 a fevereiro de 2004 durante as marés de sizígia, em diferentes zonas da praia. As amostras foram retiradas com um amostrador cilíndrico de 3,14 cm2 e fixadas em formalina salina a 5%. Em laboratório, as amostras foram passadas em malha de 0,063 mm de abertura e os organismos retidos identificados em nível de grandes grupos taxonômicos, contados e fixados em álcool etílico a 70%. A meiofauna esteve representada por oito grupos: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, adultos de Copepoda Harpacticoida e juvenis de Copepoda Harpacticoida. Nematoda foi o grupo dominante, representando 74% do total de indivíduos, seguido de Copepoda (19%). Pôde-se observar clara zonação horizontal da fauna, que se distribuiu em três faixas paralelas à linha de praia, com características significativamente distintas quanto à abundância, riqueza e densidade dos principais grupos taxonômicos. No médiolitoral médio foram observados valores significativamente mais elevados de riqueza e abundância, enquanto os valores mais baixos foram registrados no médiolitoral superior e inferior. A comunidade de meiofauna, ainda que não tenha variado significativamente entre períodos climáticos, foi mais rica e abundante nos meses secos. Os principais fatores responsáveis pelas variações espaço-temporais da meiofauna foram a ação das ondas e das marés e as variações na salinidade da água
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Species richness and geographical distribution of Cyclopoida freshwater copepods were analyzed along the La Plata River basin. Ninety-six samples were taken from 24 sampling sites, twelve sites for zooplankton in open waters and twelve sites for zooplankton within macrophyte stands, including reservoirs and lotic stretches. There were, on average, three species per sample in the plankton compared to five per sample in macrophytes. Six species were exclusive to the plankton, 10 to macrophyte stands, and 17 were common to both. Only one species was found in similar proportions in plankton and macrophytes, while five species were widely found in plankton, and thirteen in macrophytes. The distinction between species from open water zooplankton and macrophytes was supported by nonmetric multidimensional analysis. There was no distinct pattern of endemicity within the basin, and double sampling contributes to this result. This lack of sub-regional faunal differentiation is in accordance with other studies that have shown that cyclopoids generally have wide geographical distribution in the Neotropics and that some species there are cosmopolitan. This contrasts with other freshwater copepods such as Calanoida and some Harpacticoida. We conclude that sampling plankton and macrophytes together provided a more accurate estimate of the richness and geographical distribution of these organisms than sampling in either one of those zones alone.