Stolc, 1886
Description
Smooth pink or orange-coloured worms, often looking like nematodes being thin and curled when preserved. Upper side of elongate prostomium bears sensory pit lined with thickened epithelium. All locomotory chaetae bifid. In foremost chaetae upper tooth almost straight, thinner and about twice as long as lower one; teeth becoming gradually equal already in subsequent preclitellar segments. Anterior bundles with 3-5 chaetae, posterior ones with 2 chaetae, 50-90 µm long. Large coelomocytes present in body cavity When mature, ventral chaetae near male pores in IX or XI are modified as penial chaetae (but hidden inside body), 4-6 per bundle, ~60 µm long, with thick curved upper tooth, while small lower tooth is split into several denticles. After copulation, numerous stalked spermatophores are attached to different places of genital segments. Length 20-35 mm, segment number up to 140-150. Can be confused with young Limnodrilus udekemianus or Limnodrilus claparedeanus when sensory pit on prostomium remains unnoticed. The obscure beginning of chloragogen tissue on oesophagus (but very distinct in Limnodrilus) is also helpful, not to mention external spermatophores and lack of penial sheaths in mature individuals.
Burrowing in sediment.
Distribution
Cosmopolitan.
Ecology
In freshwater, particularly in the conditions of thermal pollution.
Reproduction
Asexual reproduction by architomy (fragmentation) prevailing; immature individuals with regenerated ends are common, but sexually mature individuals are rare. The latter appear mostly in the cool season when architomy is inhibited. At copulation, sperm of the partner is deposited in external spermatophores (a rare phenomen in Tubificidae). Eggs laid in oblong cocoons with unequal terminal openings and thin shell covered with fine foreign particles.
Literature
Stolc, 1886: 647; Stolc, 1888: 5, 11-14, 17-19, 25-27, 34-36, 42-43, Pl. I Figs 8-9, Pl. II Fig. 5, Pl. IV Figs 6-11, 13e; Brinkhurst and Jamieson, 1971: 540-541, Fig. 8.29A-D; Chekanovskaya, 1981: 361-363, Fig. 183; Hrabe, 1935: 12-19; Hrabe, 1981: 66-68, Pl. 10 Figs 14-16, Pl. 11 Figs 1-4; Kasprzak, 1981: 141-142, Figs 445-448.