922 resultados para ghost crabs


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Four Xanthid crabs, namely Euxanthus exsculptus (Herbst), Halimede ochtodes (Herbst), Medaeops edwardsi Guinot, and Neolimera intermadia Odhner, previously not known from the northern Arabian Sea are being reported. Each species is briefly described and illustrated.

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Rate and pattern of spoilage of some of the economically important edible species of shell fishes Mytilus edulis (Mussel), Villorita cornucopia (Clam), Neptunus pelagicus (Crab) and Scylla serrata (Crab) have been discussed in this communication. Chemical indices used for objective evaluation of quality were water extractable nitrogen (WEN), non-protein nitrogen (NPN), free α-amino nitrogen (α - NH2 -N), glycogen, lactic acid and inorganic phosphorus in addition to the subjective tests. No significant difference in the spoilage pattern of the species during ice storage was observed and these species could be preserved in ice in organoleptic acceptable condition up to 8 days, 9 days, 8 days and 11 days respectively.

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In the present paper some preliminary remarks are made on the colour patterns of all the Potamonidae of Sri Lanka. In the opinion of the author more detailed studies will show that the colour pattern of each species is a useful diagnostic aid even with difficult species like those belonging to the "Ceylonensis" complex (Fernando, 1960). Fernando (1960, 1961) has described the species of Potamonidae. Eight species are known all belonging to the genus Paratelphusa. Only one species has been illustrated in colour so far (Fernando, 1960). Black and white pictures of all the other species except Paratelphusa soror (Zenthner) have been given in Fernando (1961). Paratelphusa soror is illustrated in the present paper.

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Very few accounts of African potamonids refer to natural colouration, and the author cannot recall any describing colour patterns. The generally undistinguished appearance of these crabs is well illustrated by Rathbun (1921) on the Congo Brachyura which includes collector's notes on a number of potamonid species. This article is based on remarks extracted from a communication sent to Dr. C. H. Fernando in connection with the article "Colour patterns in Ceylonese freshwater crabs (Patomonidae)", Bulletin of the Fisheries Research Station, Ceylon, v. 21.1(1970), pp. 1-4.

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The report deals with the material on freshwater crabs, collected by the Austrian-Ceylonese hydrobiological mission 1970 from the running waters of the mountains in south-west Ceylon. The locality records for Paratelphusa (Oziotelphusa) senex (Fabricius 1798) Paratelphusa (Ceylontelphusa) sorror (Zehntner 1894) and Paratelphusa (Ceylontelphusa) rugosa (Kingsley 1880), are described.

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Investigations on the fishery, utilization and development of the crabs in Indian waters have been reviewed. Various factors relating to the improvement of fishery, keeping quality of the crab meat and possibilities for an integrated farming of commercially important crabs are discussed.

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The present report deals with the history of work done on northern Arabian Sea majids, their zoogeographical consideration and recognition of present status of certain genera which are established by recent workers. I have nothing of substance to add to previous treatment by Griffin & Tranter (1986). Emphasis is given to species inhabiting coastal waters of Pakistan. The occurrence of the genus Pleistacantha in the Arabian Sea and its adjacent gulfs is discussed in detail due to presence of a unique female which was taken by Fridtj of Nansen Cruise in 1977. This seems to be an undescribed species. At the moment the female is just given as Pleistacantha sp1 till more specimens obtained determine its position. Some interesting features of Doclea muricata are also considered.

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Stocking experiments with Eriocheir sinensis were conducted in two small, shallow lakes to study its growth pattern in 1994-1997. For the initially immature crabs, carapace width (CW) increases from 21.2 +/- 0.4 mm (mean +/- s.e.) for females and 22.3 +/- 0.5 mm for males in January, to 65.4 +/- 0.5 mm for females and 66.9 +/- 0.6 mm for males in October. There is no significant difference in CW and carapace length (CL), although there is a large difference in body weight (BW) between sexes in every month from January to August when crabs are juvenile, however, there are significant differences in CW, CL. and BW between sexes after September when the crabs become sexually mature. The growth curve from January to October fits a logistic equation and may be expressed as CW = 75.7 (1 + exp (0.914 - 0.011t))(-1) for females, and CW = 77.5 (1 + exp (0.889 - 0.011t))-1 for males, where CW is in mm, t in days. For precocious crabs (reaching maturity by the first autumn, CW does not change much from January to July, which indicates that precocious crabs stop growing. Like juveniles, the precocious crabs show no differences in CW and CL, but do show a statistically significant difference in BW between sexes.

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We observe "ghost" islands formed on terraces during homoepitaxial nucleation of GaN. We attribute the ghost islands to intermediate nucleation states, which can be driven into "normal" islands by scanning tunneling microscopy. The formation of ghost islands is related to excess Ga atoms on the surface. The excess Ga also affect island number density: by increasing Ga coverage, the island density first decreases, reaching a minimum at about 1 monolayer (ML) Ga and then increases rapidly for coverages above 1 ML. This nonmonotonic behavior points to a surfactant effect of the Ga atoms.

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Description of a new species Apocepon leucosiae sp. nov. of genus Apocepon Nierstrasz & Brender a Brandis, 1930 from Chinese waters, a redescription of Apocepon pulcher Nierstrasz & Brender a Brandis, 1930 from the type locality and the second record of Apocepon digitatum Stock, 1959 are presented. All hosts are in the brachyuran family Leucosiidae. Four purse crab species, i.e. Philyra carinata Bell, Philyra heterograna Ortmann, Leucosia sinica Shen et Chen and Leucosia anatum ( Herbst), are recorded for the first time as hosts of parasitic isopods of this genus. A brief differential diagnosis, data on the distribution and a key to the three species in the genus Apocepon are provided.

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A new species of the previously monotypic xanthid genus Crosnierius Serene & Vadon, 1981 is described from the South China Sea. The species differs from Crosnierius carinatus Serene & Vadon, 1981 in the structure of the anterolateral teeth, ambulatory leg proportions and form of the male first pleopod. Paramedaeus planifrons (Sakai, 1965) is also reported from the South China Sea, the first record of the species outside its type locality of Japan.

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A new species of spider crab, Doclea unidentata, is described from the South China Sea. Allied to D. brachyrhynchos Bleeker, 1856, and D. macracanthus Bleeker, 1856, it can easily be distinguished by its very short, unidentate rostrum. The identity of Doclea canalifera Stimpson, 1857, is resolved with the selection of a neotype, and it is here regarded as a senior subjective synonym of D. japonica Ortmann, 1893. The taxonomy of this species as well as the allied D. ovis (Fabricius, 1787) is also discussed.