Kowalewski, 1914
Description
Small smooth, pink worms. In dorsal bundles of anterior end 0-4 hair chaetae, ~85 µm long, and 2-6 bifid crotchets, ~40 µm, with shorter upper tooth. Beginning from VI-IX, dorsal crotchets are replaced by oar-shaped pectinate chaetae, ~60 µm long, their tip rounded or sometimes slightly bifid. In ventral bundles 3-6 crotchets, ~60 µm long, with shorter upper tooth. In mature individuals penial chaetae can occur in VII, 1-2 per bundle, ~75 µm long, curved, with longitudinal furrow and sharp tip. Single median male pore in VII, clitellum in VII-VIII. Posterior end modified as unsegmented tube, without chaetae, acting as gill. Length 5-12 mm, segment number 40-60. Differing from congeners and from all other tubificids in revealing oar-shaped dorsal chaetae in middle segments.
Burrowing in sediment.
Distribution
Cosmopolitan, often found in tropical countries.
Ecology
In freshwater, rare. Can build tube-like mud cases above mud surface, containing gill-like hind end.
Reproduction
Mostly asexual, by architomy (fragmentation). Mature individuals and sexual reproduction rare.
Literature
Kowalewski, 1914: 129-130, Figs 12-38; Brinkhurst and Jamieson, 1971: 526-527, Fig. 8.23I; Chekanovskaya, 1981: 285-286, Fig. 137; Hrabe, 1981: 72-73, Pl. 11 Figs 16-21, Pl. 12 Figs 1-6; Kasprzak, 1981: 180, Figs 710-718.