4 resultados para CRUSTACEA

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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Of the three superfamilies of Ostracoda present in fresh water, only the Cytheroidea had thus far no records in terrestrial environments. Here, we report on a new genus and species, Intrepidocythere ibipora n. gen. n. sp., of the ostracod superfamily Cytheroidea, from forest leaf litter in Sao Paulo State, Brazil. Judging from morphological similarities, this new genus is believed to be closely related to the genus Elpidium. Possible pathways that led to the colonisation of terrestrial habitats are discussed, and an overview is given on the distribution of the known terrestrial ostracod lineages. The present findings strengthen the idea that terrestrial ostracods are more common than previously thought, at least in tropical areas.

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The distribution of benthic organisms is directly or indirectly associated with the physical and chemical properties of the water and sediment. This study analysed the spatial and temporal distribution of Rimapenaeus constrictus in unconsolidated sublittoral sediments of two areas off the northern coast of the state of Sao Paulo, Brazil. We also analysed the association of environmental factors with the occurrence of this species. Shrimp were collected monthly from July 2001 to June 2003, with a fishing boat equipped with two double-rig nets, in the regions of Ubatuba (UBA) and Caraguatatuba (CA). The collections were made during the day, along five transects with mean depths of 5, 10, 15, 20, 25, 30, and 35 m. We obtained a total of 5478 individuals, 3403 (UBA = 2025 and CA = 1378) during the first year, and 2075 (UBA = 875 and CA = 1200) during the second year. Significant differences in abundance were observed in relation to depth, season of the year, and also in the interaction between region and depth. Higher abundances occurred in fall and winter, independently of the sampling year. The largest numbers of shrimp were caught on the 20-m transect in UBA and the 25-m transect in CA. It is concluded that the distribution pattern of this species is closely related to environmental factors, and the temperature of the bottom water and the sediment texture were the most significant variables affecting the distribution.

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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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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.