Müller, 1774
Type species Nais barbata Müller, 1774
Number of species 27. In NWE, twelwe species:
Nais alpina Sperber, 1948
Nais barbata Müller, 1774
Nais behningi Michaelsen, 1923
Nais bretscheri Michaelsen, 1899
Nais christinae Kasprzak, 1973
Nais communis Piguet, 1906a
Nais elinguis Müller, 1774
Nais pardalis Piguet, 1906a
Nais pseudobtusa Piguet, 1906a
Nais simplex Piguet, 1906a
Nais stolci Hrabe, 1981
Nais variabilis Piguet, 1906a
Description
Most typical naidids without conspicuous morphological characters like proboscis or gills. Body transparent but anterior segments often with brownish pigment. Eyes usually present. Dorsal bundles beginning from VI, consisting of hair and needle chaetae. Ventral crotchets becoming shorter and thicker from VI in most species. In mature individuals, penial chaetae in VI. Stomachal dilatation in VII or VIII. Transversal blood vessels in anterior segments, not forming any plexus.
Crawling on substratum, most species able to swim.
Distribution
Cosmopolitan.
Ecology
In freshwater, some species also in brackish water.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.
Literature
Müller, 1774: 20; Sperber, 1948: 102; Brinkhurst and Jamieson, 1971: 328-330; Chekanovskaya, 1981: 221-222; Hrabe, 1981: 38; Kasprzak, 1981: 118.