Hrabe, 1981
Description
Transparent worms, with eyes. Dorsal chaetae beginning from VI, usually with one hair chaeta, 147-212 µm long, and one needle chaeta, about 65 µm long, with long parallel teeth. In II-V ventral chaetae by 3-5, 86-107 µm long and 1.7 µm thick, with parallel teeth, upper tooth twice as long. From VI on, 2-3 enlarged chaetae per bundle (the biggest usually in VIII), 81-113 µm long and about 5 µm thick, upper tooth up to 4 times as long as lower one; in about X their number increases to 4-5, while length decreases to 70-102 µm, the ratio of two teeth gradually decreasing to 2 again. Stomachal dilatation gradual. The species can be confused with the individuals of Nais pardalis that reveal enlarged ventral chaetae. However, length of teeth becomes equal in posterior ventral crotchets, and the beginning of stomach is abrupt, in Nais pardalis. In Nais bretscheri, with longer upper tooth in all ventral crotchets, giant chaetae are much more powerful and begin from VII. Hair chaetae are somewhat longer in Nais stolci than in Nais pardalis and Nais bretscheri.
Distribution
Europe.
Ecology
In freshwater, known from streams, rare.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction not yet known.
Literature
Hrabe, 1981: 44-45, Pl. 6 Figs 1-5.