Vejdovskyella macrochaeta

(Lastockin, 1921)

Description
Small transparent worms. Prostomium as a low cap, with eyes. Dorsal chaetae beginning from VI, strikingly thick and stiff in comparison with worm's body. Dorsal bundles with thick and curved double-serrated hair chaetae, 182-368 µm long, and simple needle chaetae, 56-84 µm long; altogether 4-12 chaetae per bundle. Ordinary ventral chaetae 1-3 per bundle, 78-112 µm long and about 3 µm thick, with slightly longer upper tooth. Ventral bundles lacking in IV-V, leaving a false impression that dorsal chaetae begin from IV. In ventral bundles of VI and VII, sometimes also of VIII and IX, single (rarely double) enlarged chaetae, 82-98 µm long and up to 5.5 µm thick, strongly curved, with distal nodulus, small upper tooth and very thick, curved lower tooth. In mature individuals, single simple-pointed penial chaetae in VI. Length 1-3 mm, segment number 12-21. Presence of giant ventral chaetae is the only important character causing the difference of Vejdovskyella macrochaeta from Vejdovskyella comata. Their possible identity would need experimental verification.
Crawling on substratum.

Distribution
Europe, seldom.

Ecology
In freshwater.

Reproduction
Mostly asexual, by paratomy (budding). Mature individuals and sexual reproduction rare or seasonal.

Literature
Lastockin, 1921: 73-74, Figs 1-2; Brinkhurst and Jamieson, 1971: 348-349 (partim); Chekanovskaya, 1981: 207-208, Fig. 87; Finogenova, 1962: 220, Fig. 1; Semernoy and Timm, 1994: 133-134, Fig. 2.

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