Claparède, 1862
Description
Medium-sized to large smooth red or brownish worms; tail region often with yellow transversal stripes. All chaetae bifid crotchets with teeth of about equal length but sometimes upper tooth can be slightly shorter or longer even in chaetae of the same bundle. Anterior chaetae 4-10 per bundle, 75-135 µm long. No ventral chaetae in XI. Penial sheaths 8-14 times as long as their proximal width, usually slightly curved distally, with asymmetrical "head" on their external end. Dark chloragogen tissue on oesophagus beginning from V. Length 12-60 mm, segment number 40-95. Immature individuals can be easily confused with those of less abundant congeners, Limnodrilus claparedeanus (with slightly longer upper tooth in all chaetae of anteriormost segments) and Limnodrilus profundicola (revealing chloragogen tissue from VI on), as well as of Potamothrix moldaviensis (with shorter, softer body and with well-separated prostomium, chloragogen tissue also beginning from VI). Small but already mature individuals have been sometimes treated under the separate species name, Limnodrilus parvus. Some more forms closely related to Limnodrilus hoffmeisteri but revealing slightly different shape of penial sheath, can be recently introduced into NWE from North America.
Burrowing in sediment.
Distribution
Cosmopolitan, including tropical countries.
Ecology
In freshwater, very common, pollution-tolerant. Dominant in many tubificid communities of eutrophic water bodies. Mass occurrence in polluted habitats, often together with Tubifex tubifex. Recorded also from estuaries with periodically brackish water.
Reproduction
Sexual only. Eggs laid in oval cocoons with short appendages; soft transparent shell usually covered with adhering foreign particles. Capable for uniparental sexual reproduction (parthenogenesis or self-fertilization), particularly at higher water temperatures. Can produce several generations a year, with young individuals maturing before reaching a definite size.
Literature
Claparède, 1862: 248; Southern, 1909: 137, Pl. VIII Fig. 5A-E; Brinkhurst and Jamieson, 1971: 465-467, Figs 8.3M,O, 8.4C,H-I, 8.5E; Chekanovskaya, 1981: 317-318, Figs 153D, 154; Hrabe, 1981: 97, Pl. 17 Figs 14-15, 19; Kasprzak, 1981: 177-178, Figs 677-690.