Michaelsen, 1901b
Description
Middle-sized pink worms. Prostomium small, conical. Body cylindrical, intersegmental furrows poorly expressed. Chaetae two per bundle, slightly sigmoid with distal nodulus, with simple sharp tip or also stunt-worn in anteriormost segments, 55-160 µm long. In mature specimens two pairs of male pores as small tubercles ventrally in X and XI, and spermathecal pores in XIII. Clitellum in X-XIII. No lateral blind vessels in posterior segments. Atria in X and XI short tubular, covered with prostatic cells. Length 9-20 mm, segment number 37-55. Differs from the other lumbriculids of NWE by two pairs of distinct male pores, when mature. A similar condition can occur (very seldom) also in Lumbriculus variegatus, but this species has bifid chaetae.
Burrowing in sediment.
Distribution
Northern Europe, Siberia, Lake Baikal.
Ecology
In freshwater, in cool clean lakes only.
Reproduction
Sexual only. Eggs laid in oval cocoons with very short appendages, and covered with sediment particles.
Literature
Michaelsen, 1901b: 3; Michaelsen, 1902: 47; Svetlov, 1936: 87-93, Figs 1-2; Cook, 1971a: 213-2143, Fig. 5.3F,I; Chekanovskaya, 1981: 423-424, Fig. 210; Timm et al., 1997: 22-24, Fig. 4.