Pararhyacodrilus palustris

(Ditlevsen, 1904)

Description
Small smooth, pink worms. Hair chaetae present in foremost segments (II-V) only. In dorsal bundles, besides hair chaeta, only bifid chaetae, devoid of any intermediate teeth. Bifid crotchets both in dorsal and ventral bundles, anteriorly with longer upper tooth, buth with equal teeth in tail region. Penial chaetae several per bundle, with simple curved tip, slightly larger than ordinary chaetae. Length about 6 mm, segment number 43-69. An insufficiently studied taxon, differing from most other Rhyacodrilus-like species with several penial chaetae per bundle, in the scarcity of hair chaetae limited to foremost segments. The internal anatomical character, diagnostic of the genus Pararhyacodrilus, connection of spermatheca with oesophagus, externally not visible.
Burrowing in sediment.

Distribution
Denmark.

Ecology
In freshwater.

Reproduction
Sexual only. Eggs laid in cocoons.

Literature
Ditlevsen, 1904: 408, Pl. XVI Figs 1-2; Brinkhurst and Jamieson, 1971: 553, Fig. 8.33P-Q; Chekanovskaya, 1981: 293; Kasprzak, 1981: 143-145, Figs 456-457.

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