(Smith, 1900)
Description
Medium-sized worms. Body surface armoured with dark, irregularly arranged, small secretory papillae incrusted with foreign particles. Papillae are smaller on prostomium and on I-III, which can be retracted. Moreover, one circle of very prominent, light sensory papillae surrounding each segment on chaetal line. Sometimes another circle of smaller sensory papillae per segment. Anterior dorsal bundles with 3-15 thick hair chaetae, 263-425 µm long, and 2-4 thin pectinates, 130-160 µm long, with numerous fine intermediate teeth merged into a continuous film. After clitellum, hair chaetae become sparser and pectinates are replaced with simple-pointed needles, while in tail region dorsal bundles can be lacking altogether. Anterior ventral bundles with (1)2-4 bifid crotchets, 100-173 µm long, with upper tooth longer and thinner. After clitellum, in ventral bundles 1(2) thick, strongly sigmoid crotchets, with large curved lower tooth and tiny upper tooth. No modified genital chaetae; in mature individuals, XI devoid of any chaetae. Clitellum in 1/2 X-XII, with irregular fine secretory papillae. Length 15-35 mm, segment number 35-106. Differing from the other papillate West European tubificids (Spirosperma ferox, Embolocephalus velutinus and Haber turquinae), in its very robust light sensory papillae. Embolocephalus velutinus has also simple-pointed chaetae in some anteriormost segments, and modified spermathecal chaetae in X. Haber turquinae has both spermathecal and penial chaeta and is, moreover, much smaller.
Burrowing in sediment.
Distribution
North America, apparently introduced to Europe.
Ecology
In freshwater, in Europe until now in some larger rivers.
Reproduction
Sexual only. Eggs laid in cocoons.
Literature
Smith, 1900: 452, Pl. XXXIX Figs 1-5; Brinkhurst and Jamieson, 1971: 516, Fig. 8.16B-F; Kasprzak, 1971: 261-267, Figs 1-6; Kasprzak, 1981: 162-164, Figs 568-585; Holmquist, 1978: Figs 1A, 8A, 9A, 10B, 11A-E, 12A; Holmquist, 1979: 38-39, Figs 1-2; Juget and Lafont, 1979: 76-79, Figs 1-4.