Aiyer, 1930
Description
Transparent naidids with caudal branchial disc. Disc is prolonged, much longer than short gills, leaving its posterior half free. Mostly 3 pairs of short, contractile gills, those of the first (dorsal) pair foliate or reduced, the subsequent ones finger-like. No eyes. Dorsal bundles consisting mostly of one hair chaeta, 108-150 µm long, and 1-2 needle chaetae, 42-48 µm. Both teeth of needle chaetae equally short. Ventral chaetae 2-4 per bundle, those of II-V 64-84 µm long, slender, with upper tooth twice as long. From VI on, ventral chaetae much shorter (50-60 µm), thicker and curved, with nearly equal teeth. Length 2.5-10 mm, segment number in zooids 14, in single individuals 23-45. Differing from the other European congeners, among them Dero obtusa, in its short gills, leaving the caudal portion of prolonged branchial disc free.
Crawling on substratum. Able to swim.
Distribution
Cosmopolitan.
Ecology
In freshwater. Constructing mucous tubes.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.
Literature
Aiyer, 1930: 40-41, Figs 16-17; Sperber, 1948: 184-186, Fig. 19G, Pl. XVIII Fig. 4; Sperber, 1950: 72, Figs 23D, 24; Brinkhurst and Jamieson, 1971: 370-371, Fig. 7.14J-M; Chekanovskaya, 1981: 215-216; Kasprzak, 1981: 114-115, Figs 297-300.