Claparède, 1862
Description
Medium-sized worms. Colour yellowish red, with contrastive red dorsal vessel against the yellow background of chloragogen-covered intestine. Prostomium rounded. Tail long and tapering like in tubificids. Chaetae two per bundle, sigmoid with nodulus, mainly bifid with short parallel upper tooth but in foremost segments often simple, 80-120 µm long. External secondary annulation beginning from IV. In mature worms always external, backwards directed, transparent penes in X, 175-360 µm long. Clitellum in IX-XII. Spermathecae present, with ventral pores in IX. In tail region, two pairs of short blind transversal appendages per segment, on dorsal vessel. Testes in IX and X; posterior pair of vasa deferentia penetrate dissepiment 10/11 twice. Atria in X pear-shaped; discrete masses of prostatic cells draining into their proximal half. Length 25-60 mm, segment number 70-110. Differing from all other oligochaetes in the striking shape of backwards directed penes, when mature. Variations in such penes, as well as presence or absence of simple-pointed chaetae in some segments, have provided ground for describing this worm under different species names regarded now as synonyms.
Burrowing in sediment.
Distribution
Holarctic but recorded once also from Sudan.
Ecology
In freshwater, particularly in streams and springs but also in cool clean lakes up to large depths. Constructing mucous mud tubes, like tubificids.
Reproduction
Sexual only. Eggs laid in cocoons with thin folded shell, tapering gradually at both ends.
Literature
Claparède, 1862: 263-266, Pl.3 Fig, 11, Pl. 4 Figs 2, 13-17; Vejdovsky, 1884a: 225; Benham, 1891: 209, Pl. VII Figs 42-44; Bretscher, 1905: 665; Southern, 1909: 121, Pl. IX Figs 8a-g; Cook, 1971a: 243-244, Figs 5.5G, 5.6D-E, K; Chekanovskaya, 1981: 444-446, Fig. 222; Hrabe, 1981: 99-100, Pl. 18 Figs 1-4; Kasprzak, 1981: 197, Figs 784-788.