996 resultados para 1875-
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v.30(1943)
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v.20:no.21(1936)
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v.29:no.13(1944)
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v.20:no.3(1933)
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The planktonic chaetognaths from the Brazil-Malvinas (Falkland) confluence, extending between 36º 30' - 50º 5' S and 60º 33' - 41º 7' W, were studied. Ten species were found: Eukrohnia hamata (Möbius, 1875) (Eukrohniidae), Pterosagitta draco (Krohn, 1853) (Pterosagittidae), Sagitta enflata Grassi, 1881, Sagitta gazellae Ritter-Zahony, 1909, Sagitta hexaptera d´Orbigny, 1834, Sagitta lyra Krohn, 1853, Sagitta minima Grassi, 1881, Sagitta planctonis Steinhaus, 1896, Sagitta serratodentata Krohn, 1853, and Sagitta tasmanica Thomson, 1947 (Sagittidae). Sagitta gazellae was the most abundant species followed by E. hamata, S. tasmanica and S. serratodentata. The association analysis among the different species, salinity and temperature revealed two groups of species, one related to higher salinities and warmer waters (P. draco, S. hexaptera and S. serratodentata) and the other to lower salinities and colder waters (E. hamata, S. gazellae and S. tasmanica). The fact that P. draco and S. hexaptera, formerly defined as warm-water species, appeared further south than previously reported might be related to the existence of warm core eddies up to 46º S in September and October 1988.
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Cinco novas espécies de Blaptica Stål, 1875 do Estado do Rio Grande do Sul, Brasil são descritas e apresentadas ilustrações de Blaptica dubia.
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The skull morphometrics of adult male Antarctic fur seal, Arctocephalus gazella (Peters, 1875) and South American fur seal, A. australis (Zimmermann, 1783) were investigated using a collection of 45 and 38 skulls, respectively. Eighteen measurements were taken for each specimen. Comparative univariate and multivariate statistical analyses included standard statistics, one-way analysis of variance, principal component analysis and discriminant analysis. Individual variation was relatively high for some variables, as expressed by the coefficient of variation. Skulls of A. gazella were larger than those of A. australis for all but two variables: squamosal jugal suture and rostral length. Both species differed significantly as shown by both univariate and multivariate analyses. The discriminant function correctly classified all specimens. The standardized canonical coefficients showed that the variables which most contribute to the differentiation between species were, in decreasing order, the rostral length, palatal length, palatal width at postcanine 5 and braincase width. The present study corroborates that A. gazella and A. australis are phenotipically distinct species.
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v.18:no.5(1931)
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No período entre dezembro de 2001 a dezembro de 2003, realizaram-se coletas com rede entomológica de insetos visitantes das flores de Eryngium horridum (Apiaceae) na Região do Vale do Rio Pardo, RS, Brasil. Esta planta é perene, freqüente em campos secos e apresenta expressiva dispersão. Possui, no Rio Grande do Sul, época de floração entre novembro e janeiro. Foram capturados 1.066 insetos visitantes, destes, 569 Syrphidae. Identificaram-se 60 espécies de Syrphidae, distribuídas em 16 gêneros. O gênero Palpada Macquart, 1834 foi dominante, e Ornidia Lepeletier & Serville, 1828 e Toxomerus Macquart, 1855 abundantes. Das espécies mais freqüentes, Palpada furcata (Wiedemann, 1819) ocupou posição mais elevada. Os sirfídeos apresentaram preferência pelas temperaturas entre 28 e 32ºC, e foram mais freqüentemente coletados entre as 10 e 14 horas, com picos entre as 10 e 11 horas. As fêmeas foram as mais freqüentes. O predomínio de sirfídeos robustos e mais ágeis sobre sirfídeos de menor porte como Toxomerus e Allograpta Osten Sacken, 1875, pode ter sido resultante de competição interespecífica. Eristalinus taeniops (Wiedemann, 1818) é pela primeira vez citada para o Estado do Rio Grande do Sul. A alta diversidade e abundância dos espécimes coletados nas flores de E. horridum são indicadores da importância desta na dieta dos sirfídeos, visto que possui grande número de inflorescências e floração ocorrendo nos meses de baixa oferta de recursos alimentares na área de estudo.
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Ethological isolation of individuals from three allopatric Grammostola populations of Uruguay, G. iheringi (Keyserling, 1891), G. mollicoma (Auserer, 1875) northern population and G. mollicoma southern population, was tested under laboratory conditions. Grammostola iheringi behaved as a reproductive isolated species, whereas the two populations of G. mollicoma did not show ethological isolation between them. However, ecological isolating reproductive mechanisms could be acting on G. mollicoma populations. Artificial burrows seem to be important for reproductive isolation in these species.
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v.12:no.15(1928)
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no.1(1922)
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Fecundity is one of the most important parameters in studying the reproductive output of Pleocyemata decapods, especially because of its relationship to the efficiency of population replacement. Knowledge of fecundity provides basic elements for understanding the reproductive strategies, dynamics, and evolution of a given population. The present investigation provides informations on fecundity, egg size, egg loss, and the relationship between fecundity and selected environmental features, for the spider crab Mithraculus forceps (A. Milne Edwards, 1875). Ovigerous crabs were collected each month during 2000, by SCUBA diving, at Couves Island (23º25'25"S, 44º52'03"W) on the northeastern coast of the state of São Paulo, Brazil. A total of 40 ovigerous females with egg in early development (initial stage) and 28 final stage eggs were obtained and analyzed. Mean fecundity, from eggs of the initial stage, was 402.8 ± 240.1 eggs, ranging from 60 to 1,123 eggs. Sizes of females ranged from 9.4 to 14.0 mm carapace width. Mean egg size was 0.56 ± 0.06 mm diameter. A 20.33% rate of egg loss was estimated by comparing the fecundities of batches of eggs in early and late development (40 initial batches and 28 final stages batches). There were no significant relationships between the water temperature or salinity and variations in fecundity. As in most brachyuran species, M. forceps showed a strong conservative relationship between fecundity and body size.
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A ictiofauna de uma praia arenosa da Ilha do Frade, Vitória, ES, foi amostrada mensalmente entre maio/2004 e abril/2005. Foram coletados 2.689 indivíduos de 26 famílias e 45 espécies de Teleostei, a maioria em estágio juvenil. A família Sciaenidae apresentou o maior número de espécies. As capturas mensais evidenciaram que as espécies numericamente mais importantes foram: Lutjanus synagris (Linnaeus, 1758), Archosargus rhomboidalis (Linnaeus, 1758), Eucinostomus lefroyi (Goode, 1874) e Paralonchurus brasiliensis (Steindachner, 1875); com relação ao peso, Cyclichthys spinosus (Linnaeus, 1758), A. rhomboidalis, E. lefroyi e L. synagris dominaram. O número de indivíduos e a biomassa variaram significativamente (p<0,01) entre os meses. O índice de Shannon-Wiener (H') apresentou pequenas variações mensais, não evidenciando uma tendência sazonal.