Dero (Dero) nivea Aiyer

Recognition

Single dorsal hair chaetae are present. Dorsal needle chaetae are single and bifid, but with small, equal teeth. The ventral chaetae number 4 per bundle and the anterior ones have a elongate upper teeth. Posterior gills are present only in this genus. In this species the gills are represented by 3 pairs of digitiform lobes, but no elongate palps, one pair of lobes may be reduced. When preserved, the anal segment surpasses the tips of the digitiform lobes making them difficult to see. There are no coelomocytes in this subgenus. May be taken for a Nais if the gills are missing, but the chaetae differ and there are never eyes.

Summary

The length is 2.5 to 10 mm. It usually lives in fixed tubes.

Distribution

It is widespread over much of the world.

26 MAY 1996 D.L. Gustafson
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dlg@rivers.oscs.montana.edu