A new nematode species, Comephoronema multipapillatum sp. n. (Cystidicolidae), is described from the anterior intestine and caecum of the squirrelfish Holocentrus adscensionis (Osbeck) (Beryciformes: Holocentridae) collected in Angra dos Reis, State of Rio de Janeiro, offshore Brazil. The new species was placed in Comephoronema Layman, 1933 by having an oval oral aperture, four submedian labia, four bilobed submedian sublabia, two narrow lateral pseudolabia and four single cephalic papillae, but mainly by numerous precloacal papillae in males (more than six pairs), in which it differs from species of the otherwise morphologically similar genus Ascarophis van Beneden, 1871. Comephoronema multipapillatum sp. n. can be easily distinguished from other congeners based on the high number of precloacal papillae in males (18 pairs + one unpaired) and also by the bidentate plate structure on the inner margin of pseudolabia, mature eggs with two long filaments on a single pole, body length of male (9.4-11.5 mm) and female (10.2-19.9 mm), left spicule size (222-278 µm) and length ratio of spicules (1 : 2.2-2.8). This is the fifth nominal species of Comephoronema, the first nematode registered parasitizing H. adscensionis and the first species of the genus in the Neotropical part of the Atlantic Ocean.
Similar-aged leaflets of kidney beán plants grown either in soii or sand culture but otherwise under identical laboratory conditions, were exposed to acute O3 concentrations of 0.5 to 0.7 pmol mol"l for 1-1.5 h with a 15 to 20 min respite interval in the middle of the ozonation period. The CO2 exchange versus leaf intemal CO2 concentration relationships were determined just before ozonation, during respite period and immediately after the treatment. Under comparable absorbed O3 fluxes the calculated mesophyll conductance (gn,) and measured C02-saturated photosynthesis (Pj) in leaflets of sand-grown plants declined more rapidly than in leaflets of soil-grown plants. A rise in the CO2 compensation concentration in the sand-grown plants was also more pronounced. About 20 % greater thickness of leaves of the sand-grown plants was probably not the cause for their higher susceptíbility to absorbed O3. From the proportíonal decline in ^nd Pg, it is concluded that possible differences in patchiness of stomatal closure under O3 were also not the cause. A weaker O3 defence systém in the mesophyll cells of the sand- grown plants may be the cause of their greater sensitivity to absorbed O3.
The need for continuous recording rain gauges makes it difficult to determine the rainfall erosivity factor (Rfactor) of the Universal Soil Loss Equation in regions without good spatial and temporal data coverage. In particular, the R-factor is only known at 16 rain gauge stations in the Madrid Region (Spain). The objectives of this study were to identify a readily available estimate of the R-factor for the Madrid Region and to evaluate the effect of rainfall record length on estimate precision and accuracy. Five estimators based on monthly precipitation were considered: total annual rainfall (P), Fournier index (F), modified Fournier index (MFI), precipitation concentration index (PCI) and a regression equation provided by the Spanish Nature Conservation Institute (RICONA). Regression results from 8 calibration stations showed that MFI was the best estimator in terms of coefficient of determination and root mean squared error, closely followed by P. Analysis of the effect of record length indicated that little improvement was obtained for MFI and P over 5- year intervals. Finally, validation in 8 additional stations supported that the equation R = 1.05·MFI computed for a record length of 5 years provided a simple, precise and accurate estimate of the R-factor in the Madrid Region.
In the epiphytic tillandsioids, Guzmania monostachia, Werauhia sanguinolenta, and Guzmania lingulata (Bromeliaceae), juvenile plants exhibit an atmospheric habit, whereas in adult plants the leaf bases overlap and form water-holding tanks. CO2 gas-exchange measurements of the whole, intact plants and δ13C values of mature leaves demonstrated that C3 photosynthesis was the principal pathway of CO2 assimilation in juveniles and adults of all three species. Nonetheless, irrespective of plant size, all three species were able to display features of facultative CAM when exposed to drought stress. The capacity for CAM was the greatest in G. monostachia, allowing drought-stressed juvenile and adult plants to exhibit net CO2 uptake at night. CAM expression was markedly lower in W. sanguinolenta, and minimal in G. lingulata. In both species, low-level CAM merely sufficed to reduce nocturnal respiratory net loss of CO2. δ13C values were generally less negative in juveniles than in adult plants, probably indicating increased diffusional limitation of CO2 uptake in juveniles., J. D. Beltrán ... [et al. ]., and Obsahuje bibliografii
The erythrinid fish Hoplias malabaricus in Paraguay harbour two species of proteocephalid cestodes, Proteocephalus regoi sp. n. and Nomimoscolex matogrossensis Rego et Pavanelli, 1990. The former species differs from most South American members of Proteocephalus from fishes by: 1) presence of a small apical organ, 2) distribution of vitellaria, which do not reach to posterior margin of segment and 3) posterior position of vagina. Nomimoscolex matogrossensis is redescribed on the basis of type and recent material, with emphasis given to the morphology of genital organs and scolex, which possesses an apical organ. Both species possess a dense network of osmoregulatory canals in the postacetabular region of both scolex and neck. Proteocephalus regoi sp. n. is the first representative of the subfamily Proteocephalinae parasitizing erythrinid fish.