Rhyacodrilus subterraneus

Hrabe, 1963

Description
Small smooth, pink worms. Anterior dorsal bundles with 1-3 smooth hair chaetae, 135-350 µm long, and mostly 2-3 (up to 5) pectinates, 47-80 µm long, with upper tooth straighter and about twice as long as lower one, and with numerous very thin intermediate teeth. Anterior ventral bundles with 2-6 crotchets, 60-103 µm long, with upper tooth at least twice as long as lower one. In posterior segments, 1-4 bifid crotchets, with equal teeth or upper tooth slightly shorter. Penial chaetae near male pores in XI single, 72-95 µm long, with simple curved tip. Spermathecal pores located near anterior edge of X. Clitellum in X-XII. Coelomocytes in body cavity present but not always distinctly visible. Length 6-17 mm, segment number 43-63. Differing from congeners in revealing single simple-pointed penial chaetae, longer upper tooth in anterior crotchets, and scarce coelomocytes.
Burrowing in sediment.

Distribution
Europe, eastern North America.

Ecology
In freshwater, in streams as well as in groundwater.

Reproduction
Sexual only. Eggs laid in cocoons.

Literature
Hrabe, 1963: 249-252, Figs 1-7; Brinkhurst and Jamieson, 1971: 551-552, Fig. 8.32A-F; Kasprzak, 1981: 145, Figs 464-470; Timm et al., 1997: 16-18, Fig. 1.

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