Coates, 1986
Type genus Propappus Michaelsen, 1905
Number of species 3. In NWE, one species:
Propappus volki Michaelsen, 1916
Description
Small white worms. Prostomium with or without tentacle. Chaetae 3 (seldom 2 or 4) per bundle as bifid crotchets, with slightly shorter upper tooth. Two large glands attached to the back side of each chaetal bundle, inside body. Clitellum in 1/2 XII-XIV, male pores at its anterior edge. Spermathecal pores ventrally in the anterior half of IV. Considering chaetae, can be confused with some small tubificids, but distinguishable on the ground of a different position of reproductive system. The single genus, Propappus, was treated as the most primitive group of the Enchytraeidae, until separated by Coates, 1986 to form its own family. Sharing a set of characters of reproductive system with Enchytraeidae (including male pores in XII, and spermathecae shifted far forward) but differing from them in having bifid chaetae, large glands at chaetal bundles, spermathecal pores near 3/4 instead of 4/5, as well as in the primary aquatic habitat.
Crawling in interstitial crevices, probably also burrowing in sediment.
Distribution
Palaearctic.
Ecology
In freshwater.
Reproduction
Sexual only, with eggs laid in cocoons.
Literature
Coates, 1986: 418-419.