| 附註 |
P. obscura was collected from fast flowing small rivers and ditches with generally clear waters. The species also occurs in downstream habitats. Thus it inhabits both so-called low and high predation sites described in the guppy literature (see Magurran, 2005). The locus typicus is a site in the headwaters of the Oropuche River. The river is here about 5 meters wide and fast flowing with a maximum
depth of 1 meter. The riverbed is gravel and sand with some larger rocks in the middle. Submerse plants are absent, but the vegetation on the river banks focally reaches into the water and provides shaded sections throughout most of the day. On the 13.2.2008 (1 p.m., air temperature 25.5°C) the following parameters were recorded: clear water, water temperature 22.5°C, hardness 5–10, conductivity 51 mS, pH 7, nitrate 0, nitrite 0. Accompanying fishes were Rivulus hartii, Astyanax spec., Ancistrus spec. and small cichlids. The inclusion of
cichlids and characins defines the habitat as high predation site. |