Action potentials (APs) and sodium current from the slowly and the rapidly adapting stretch receptor neurons in the crayfish (Astacus astacus) were recorded with a two microelectrode voltage- and current-clamp technique. In the rapidly adapting neuron the APs had a duration of 3.2 +/- 0.2 ms (means +/- SE) and an amplitude of 55.2 +/- 1.5 mV. In the slowly adapting receptor neuron APs had a dur...

Light responses (ReP) and pre-stimulus membrane potential (PMP) and conductance of photoreceptors of Astacus leptodactylus and Limulus polyphemus (lateral eye) were recorded and changes were observed when the photoreceptor was depolarized by the action of external ouabain of high potassium concentration application. 1 mM/1 ouabain application causes a transient increase of PMP and ReP in Limulu...

the astacus leptodactylus specimens were collected from four sites of aras reservoir, north-west of iran and examined for the epibionts during 2009. protozoan epibionts from ciliophora (one genus and seven species) and tracheophyta were isolated from the cuticular surface of different body parts of narrow-claw crayfish, a.leptodactylus. seasonal prevalence of infestation was determined in 394 i...

Invasive species are a major cause of species extinction in freshwater ecosystems, and crayfish species are particularly pervasive. The invasive American signal crayfish Pacifastacus leniusculus has impacts over a range of trophic levels, but particularly on benthic aquatic macroinvertebrates. Our study examined the effect on the macroinvertebrate community of removal trapping of signal crayfis...

The effect of increased impulse activity upon voltage-dependent Ca2+ currents was studied in the cell body of a crayfish phasic motoneuron using two-electrode voltage-clamp technique. Increased electrical activity in this relatively inactive motoneuron produces a short-term and long-term reduction in the voltage-dependent Ca2+ current. Both forms of activity-dependent reduction in Ca2+ current ...

Appendages are important sources of sensory information for all animals that possess them but they are commonly damaged in nature. We describe how the tactile system of the crayfish Cherax destructor functioned when subjected to the kind of damage found in wild-caught or cultured animals. Touch information was methodically varied by the removal of antennae and chelae. The resulting behaviour wa...

Virilastacus retamali, a new species of burrowing parastacid, is described from the peatland in Rucapihuel located along the Coastal Cordillera from the province of Osorno, southern Chile. This is the third species of the genus Virilastacus described to date. It differs from V. araucanius and V. rucapihuelensis in the following morphological characters: 1) large eyes; 2) short rostral carina; 3...

The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and...