(Vejdovsky, 1876a)
Description
Medium-sized smooth pink worms. In anterior dorsal bundles 3-8 smooth hair chaetae, 427-432 µm long, and 3-7 pectinates, 80-135 µm long, with equal main teeth and some small intermediate teeth. Anterior ventral chaetae 4-8 per bundle, about 109 µm long, with teeth of nearly equal length. In posterior chaetae, upper tooth can be somewhat shorter in both dorsal and ventral crotchets. Penial chaetae 2-5 per bundle, 100-150 µm long, with blunt bent tip or with reduced upper tooth. Distal tips of penial chaetae lying close to each other, often hardly protruding over body surface from aperture shared with male pore. Clitellum in 1/2 X-1/2 XII. In body cavity numerous roundish, granular coelomocytes, about 20 µm in diameter. Length 15-35 mm, segment number 60-110. Can be confused with Tubifex tubifex, Ilyodrilus templetoni, or some species of Potamothrix, if penial chaetae and coelomocytes, typical of Rhyacodrilinae, remain unnoticed. More roundish, often inflated prostomium also facilitates to distinguish this species. In comparison with the other species of Rhyacodrilinae, chaetae of Rhyacodrilus coccineus are most trivial, without any specific characters.
Burrowing in sediment.
Distribution
Holarctic but known also from China, Australia, and the Antarctic islands.
Ecology
In freshwater.
Reproduction
Sexual only. Eggs laid in cocoons.
Literature
Vejdovsky, 1876a: 193; Brinkhurst and Jamieson, 1971: 547-549, Fig. 8.31A-D; Chekanovskaya, 1981: 293-294, Fig. 140; Hrabe, 1981: 62-64, Pl. 10 Figs 1-10; Kasprzak, 1981: 145, Figs 471-475.