Oken, 1815
Type species Nais digitata Müller, 1774
Number of species 22. In NWE, four species:
Dero digitata (Müller, 1774)
Dero dorsalis Ferronière, 1899
Dero nivea Aiyer, 1930
Dero obtusa D'Udekem, 1855
Description
Naidids with contractile gills on caudal branchial disc but without palps. No eyes. Dorsal bundles with hair and needle chaetae begin either from VI or, in one species, from IV. In mature individuals, male pores in VI, without genital chaetae. Sometimes (e. g., in Sperber, 1948; Brinkhurst and Jamieson, 1971; Kasprzak, 1981; but not here) including also the related genera Aulophorus (with non-contractile palps) and Allodero (without any gills formed on branchial disc) as subgenera.
Distribution
Cosmopolitan, with most species in warmer regions.
Ecology
In freshwater, usually preferring warm water bodies with soft sediment. Tube-builders.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.
Literature
Oken, 1815: 363; Gervais, 1838: 18; Sperber, 1948: 158-160; Brinkhurst and Jamieson, 1971: 359-360; Chekanovskaya, 1981: 210-211; Hrabe, 1981: 56; Kasprzak, 1981: 109.