(Piguet, 1928)
Description
Small smooth, pink worms. Hair chaetae present in anteclitellar segments and midbody, anteriorly 234-340 µm long, caudad gradually shorter, up to 65 µm. Bifids in anterior dorsal bundles by 4-5, with equal teeth, without any intermediate teeth, 98-110 µm long. In posterior dorsal bundles 2-3 crotchets, their lower tooth becoming gradually thicker, but upper one thin, short and erect. Ventral chaetae, 4-7 in anterior bundles, 111-124 µm long, with longer and thinner upper tooth, but similar to dorsal ones in posterior segments. Penial chaetae 4-6 per bundle, 120-134 µm long, with simple thin curved tip. Clitellum in XI-XII. Length up to 20 mm, segment number up to 106. An insufficiently studied taxon, differing from most other Rhyacodrilus-like species with several penial chaetae per bundle, in the slight peculiarities in chaetae. The internal anatomical character, diagnostic of the genus Pararhyacodrilus, connection of spermatheca with oesophagus, externally not visible.
Burrowing in sediment.
Distribution
So far definitely known from some Swedish lakes.
Ecology
In freshwater.
Reproduction
Sexual only. Eggs laid in cocoons.
Literature
Piguet, 1928: 94-97, Fig. 7; Brinkhurst and Kennedy, 1962: 188, Pl. VII; Brinkhurst and Jamieson, 1971: 553-554, Fig. 8.33R-W; Chekanovskaya, 1981: 296-298, Fig. 142; Kasprzak, 1981: 144-145, Figs 458-463.