(Bretscher, 1896)
Description
Small transparent worms. Prostomium as a low cap, without eyes. Dorsal bundles beginning from VI. Dorsal hair chaetae by 2-9, 200-400 µm long, smooth (finely serrated at high magnification); besides, 3-9 fine single-pointed needle chaetae, 55-193 µm long. Ventral chaetae in II-V by 2-4, with slightly longer upper tooth, 92-118 µm long, from VI on mostly singly, 60-90 µm long. In VI (or also in some following segments) ventral chaetae particularly thick and curved, with upper teeth split into 2-3 branches. In mature individuals penial chaetae by 1-2, with simple hooked tip, 86 µm long. Length 1.3-3 mm, segment number in zooids 11-14, in single individuals 19-24. Differing from another species having giant ventral chaetae, Vejdovskyella macrochaeta, in the split upper tooth of giant chaetae, a full set of anterior ventral chaetae, thinner and smoother hair chaetae, and lack of eyes. Separated to a subgenus Machetna by Semernoy and Timm, 1994.
Distribution
Holarctic.
Ecology
In freshwater, particularly in bigger lakes and rivers.
Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.
Literature
Bretscher, 1896: 509-510; Sperber, 1948: 140-141; Sperber, 1950: 66-67, Fig. 18; Brinkhurst and Jamieson, 1971: 347-349 (partim); Chekanovskaya, 1981: 206-207, Fig. 86; Hrabe, 1981: 51, Pl. 8 Figs 5-7; Kasprzak, 1981: 116-117, Figs 305-307; Semernoy and Timm, 1994: 131, 136, Fig 4.