67 resultados para Crustacea fossil

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


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Nursery performance, development, and RNA:DNA ratio were investigated in Farfantepenaeus paulensis (Pérez-Farfante, 1967) postlarvae acclimated from a salinity of 30‰ to higher (35‰) or lower (16, 22 and 29‰) salinities and reared for 20 days. Overall, higher final weight, yield and growth rate were observed at a salinity of 29‰. RNA:DNA ratio indicated reduced growth potential at a salinity of 35‰. Low salinities resulted in more developed individuals. Thus, early postlarval F. paulensis should not be stocked in salinities higher than that of the original hatchery, otherwise in lower salinities postlarvae should be older and/or have an extended nursery phase. Results may assist in the development of nursery rearing protocols for F. paulensis, an alternative species for aquaculture in subtropical areas.

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Os estádios de desenvolvimento dos ovários da lagosta Panulirus echinatus Smith, 1869 foram caracterizados com base nos aspectos macroscópicos, microscópicos e na relação gonadossomática (RGS). Através de amostragem mensal (novembro/1999 a outubro/2000) foram capturadas 711 fêmeas, empregando-se redes de espera de fundo. Retirou-se a região dorsal da carapaça para avaliação dos ovários. Estes foram dissecados, pesados, fixados em solução de Bouin e submetidos aos procedimentos histológicos. A análise microscópica dos ovários foi avaliada pela presença de células germinativas nas diferentes fases de desenvolvimento. Esta análise quando associada a macroscopia (mudança de cor e volume das gônadas no cefalotórax) e a relação gonadossomática (RGS) possibilitou a caracterização de cinco estádios de desenvolvimento: imaturo (I), em desenvolvimento (II), pré-maturação (III), maduro (IV) e pós-desova (V). As análises estatísticas confirmaram que a RGS pode ser utilizada como indicadora dos estádios de maturidade.

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A new genus and species of parasitic copepod (Clausiidae), Spionicola mystaceus, associated with the polychaete Dipolydora armata (Spionidae) is described and figured. The new copepod has an elongate body, 5-segmented antennule, 2-segmented rami on legs 1 and 2, 2 spines representing leg 3, no leg 4, leg 5 well developed and reduced armature elements on feeding limbs. The host is a mollusk-shell borer, collected off São Sebastião Island, State of São Paulo, Brazil.

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A new family, Trichopeltariidae, is proposed to accommodate Sphaeropeltarion edentatum, new genus and species, and four additional genera traditionally placed in the family Atelecyclidae: Trichopeltarion A. Milne-Edwards, 1880 (type genus); Peltarion Hombron & Jacquinot, 1846; Podocatactes Ortmann, 1893; and Pteropeltarion Dell, 1972. Additionally, four new species of Trichopeltarion are described and illustrated. The new family exhibits characters of neither superfamilies of the Section Eubrachyura and is assigned to its own superfamily, Trichopeltarioidea nov. Keys to the genera of Trichopeltariidae fam. nov. and to all species in the family are presented (species of Trichopeltarion excepted). Six new combinations are proposed or confirmed. The genus Krunopeltarion Števčić, 1993, is merged into the synonymy of Trichopeltarion. A lectotype is selected for Trichopeltarion corallinum (Faxon, 1893).

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The only specimen listed in the original description of Scyllarides deceptor Holthuis, 1963 is the holotype from São Paulo, Brazil, presently housed in the Leiden Museum. From the original description, however, it is clear that the new species was actually based on a number of additional specimens. Six of them exist in the collections of the Museum of Zoology in São Paulo, and are shown herein to be paratypes of S. deceptor. Scyllarides deceptor and S. brasiliensis Rathbun, 1906, continue to be confounded with one another, in consequence of their very similar color patterns and locally sympatric distributions. As many as 251,786 tons of slipper lobsters have been landed in Santa Catarina between 2000 and 2007. These catches have been attributed to S. deceptor alone and did not take into consideration the existence of a second species in the area, S. brasiliensis. Correct recognition of slipper-lobster species will be critical to properly evaluate the lobster stocks in southeastern Brazil. An opportunity is taken herein to elaborate on the taxonomy of S. deceptor and S. brasiliensis.

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A new species of Euprognatha Stimpson, 1871 from off coast of Brazil (Canopus Bank, 02º15.3'00"S - 38º16.0'00"W) is described and illustrated, namely Euprognatha limatula n. sp. The new species is compared to its congeners. Lectotypes are designated for E. acuta A. Milne-Edwards, 1880 and E. granulata Faxon, 1893. A key to the species of Euprognatha is provided.

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The description of Micropygomyia brandaoi, a new species of fossil phlebotomine sand fly, is based on one male specimen obtained from Dominican amber of the Miocene period (20 million years). In this new species, the fifth palpal segment is long, the coxite lacks a setal tuft and the style shows four well-developed spines. This set of characters allowed us to place the new species in the genus Micropygomyia Barretto.

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The description of Micropygomyia brandaoi, a new species of fossil phlebotomine sand fly, is based on one male specimen obtained from Dominican amber of the Miocene period (20 million years). In this new species, the fifth palpal segment is long, the coxite lacks a setal tuft and the style shows four well-developed spines. This set of characters allowed us to place the new species in the genus Micropygomyia Barretto

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The objective of this study was to carry out a taxonomic review of fossil American phlebotomine sand flies and describe two new species found in amber in the Dominican Republic. The gonostyle of one of these, Micropygomyia dorafeliciangeliae nov. sp., (=Lutzomyia dorafeliciangeliae, species group oswaldoi), has five spines, similar to that of Micropygomyia paterna (Quate, 1963) (= Lutzomyia paterna, species group oswaldoi), but they may be distinguished by the alpha/gamma ratio, which is <1.0 in the new species and >1 in the latter. Pintomyia dominicana nov. sp. (=Lutzomyia dominicana, species group verrucarum) has four spines on the gonostyle and presents a long bristle on the apex of the paramere, which distinguishes it from the other fossil species. With the description of these two new species, a total of 14 species of the American fossil phlebotomine sand flies has been described, 10 of which belong to the genus Pintomyia. An identification key for male fossil species is presented

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Aims. We create a catalogue of simulated fossil groups and study their properties, in particular the merging histories of their first-ranked galaxies. We compare the simulated fossil group properties with those of both simulated non-fossil and observed fossil groups. Methods. Using simulations and a mock galaxy catalogue, we searched for massive (>5 x 10(13) h(-1) M-circle dot) fossil groups in the Millennium Simulation Galaxy Catalogue. In addition, we attempted to identify observed fossil groups in the Sloan Digital Sky Survey Data Release 6 using identical selection criteria. Results. Our predictions on the basis of the simulation data are: (a) fossil groups comprise about 5.5% of the total population of groups/clusters with masses larger than 5 x 10(13) h(-1) M-circle dot. This fraction is consistent with the fraction of fossil groups identified in the SDSS, after all observational biases have been taken into account; (b) about 88% of the dominant central objects in fossil groups are elliptical galaxies that have a median R-band absolute magnitude of similar to-23.5-5 log h, which is typical of the observed fossil groups known in the literature; (c) first-ranked galaxies of systems with M > 5 x 10(13) h(-1) M-circle dot, regardless of whether they are either fossil or non-fossil, are mainly formed by gas-poor mergers; (d) although fossil groups, in general, assembled most of their virial masses at higher redshifts in comparison with non-fossil groups, first-ranked galaxies in fossil groups merged later, i.e. at lower redshifts, compared with their non-fossil-group counterparts. Conclusions. We therefore expect to observe a number of luminous galaxies in the centres of fossil groups that show signs of a recent major merger.

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Context. Fossil systems are defined to be X- ray bright galaxy groups ( or clusters) with a two- magnitude difference between their two brightest galaxies within half the projected virial radius, and represent an interesting extreme of the population of galaxy agglomerations. However, the physical conditions and processes leading to their formation are still poorly constrained. Aims. We compare the outskirts of fossil systems with that of normal groups to understand whether environmental conditions play a significant role in their formation. We study the groups of galaxies in both, numerical simulations and observations. Methods. We use a variety of statistical tools including the spatial cross- correlation function and the local density parameter Delta(5) to probe differences in the density and structure of the environments of "" normal"" and "" fossil"" systems in the Millennium simulation. Results. We find that the number density of galaxies surrounding fossil systems evolves from greater than that observed around normal systems at z = 0.69, to lower than the normal systems by z = 0. Both fossil and normal systems exhibit an increment in their otherwise radially declining local density measure (Delta(5)) at distances of order 2.5 r(vir) from the system centre. We show that this increment is more noticeable for fossil systems than normal systems and demonstrate that this difference is linked to the earlier formation epoch of fossil groups. Despite the importance of the assembly time, we show that the environment is different for fossil and non- fossil systems with similar masses and formation times along their evolution. We also confirm that the physical characteristics identified in the Millennium simulation can also be detected in SDSS observations. Conclusions. Our results confirm the commonly held belief that fossil systems assembled earlier than normal systems but also show that the surroundings of fossil groups could be responsible for the formation of their large magnitude gap.

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We present a new insight on NGC 6034 and UGC 842, two groups of galaxies previously reported in the literature as being fossil groups. The study is based on optical photometry and spectroscopy obtained with the CTIO Blanco telescope and Sloan Digital Sky Survey archival data. We find that NGC 6034 is embedded in a large structure, dominated by three rich clusters and other small groups. Its first and next four ranked galaxies have magnitude differences in the r band and projected distances which violate the optical criteria to classify it as a fossil group. We confirm that the UGC 842 group is a fossil group, but with about half the velocity dispersion that is reported in previous works. The velocity distribution of its galaxies reveals the existence of two structures in its line of sight, one with sigma(nu) similar to 223 km s(-1) and another with sigma(nu) similar to 235 km s(-1), with a difference in velocity of similar to 820 km s(-1). The main structure is dominated by passive galaxies, while these represent similar to 60% of the second structure. The X-ray temperature for the intragroup medium of a group with such a velocity dispersion is expected to be kT similar to 0.5-1 keV, against the observed value of kT similar to 1.9 keV reported in the literature. This result makes UGC 842 a special case among fossil groups because (1) it represents more likely the interaction between two small groups, which warms the intragroup medium and/or (2) it could constitute evidence that member galaxies lost energy in the process of spiraling toward the group center, and decreased the velocity dispersion of the system. As far as we know, UGC 842 is the first low-mass fossil group studied in detail.

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The gamitana is a species of socio-economic importance in the Peruvian Amazon, often intensively produced locally for human consumption. Because of this, more studies concerning parasite populations affecting this species culture are necessary. In this study, a heavy copepod infestation of Perulernaea gamitanae is reported in a managed culture of gamitana. The prevalence of infection was 100% and mortality of the fish population was complete. The average intensity and abundance of the parasite was 268.8 parasites per individual.

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Adamussium Jonkersi sp nov is described from the Late Oligocene Destruction Bay Formation Wrona Buttress area King George Island (South Shetlands) West Antarctica The unit characterized by volcanic sandstone is a shallow marine( succession deposited in a moderate- to high-energy environment The thin shelled pectinids collected from the lower part of the unit are preserved mostly as complete valves Shell thickness sculpture pattern and umbonal angle suggest a free-living inactive swimming life habit

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Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)