Henle, 1837
Type species Enchytraeus albidus Henle, 1837
Number of species about 55. At least two species have been repeatedly recorded from fresh waters of NWE:
Enchytraeus buchholzi Vejdovsky, 1879
Enchytraeus christenseni Dózsa-Farkas, 1992
Both species are primarily terrestrial. Many other species of Enchytraeus inhabit soil and seashores in NWE and can accidentally occur also in some fresh-water bodies.
Description
Small to large, mostly white enchytraeids. Chaetae straight, without nodulus, in different numbers per bundle. Head pore in 0/1. Male pores in XII (can be shifted forwards in architomic forms). Internal characters: Three pairs of pharyngeal glands. Gradual transition between oesophagus and intestine; no oesophageal or intestinal appendages; paired, unbranched peptonephridia on pharynx. Blood colourless or yellowish, dorsal vessel reaches to clitellar region or behind clitellum. Spermathecae simple, communicating with oesophagus, usually with glands on ectal duct. Seminal vesicle present but not lobed. Vasa deferentia long. Penial bulbs present. Male pores without atrial glands. Since it is the oldest known genus of the family, a number of species were originally described as belonging to it, but were later separated into other genera. There is a tendency among laymen, to identify every enchytraeid, found in the limnic environment, as "Enchytraeus sp.", or even as the type species, Enchytraeus albidus. In fact, only two above listed tiny species of this genus can be expected in this habitat. They can be recognized by the small but indefinite number (2-3) of straight chaetae and by the shape of spermathecae.
Burrowing in sediment.
Distribution
Cosmopolitan.
Ecology
In soil, the marine littoral, and freshwater.
Reproduction
Mostly sexual only, with eggs laid in cocoons, but asexual reproduction by architomy (fragmentation) occurring in some species.
Literature
Henle, 1837: 74-90; Nielsen and Christensen, 1959: 89-91; Chekanovskaya, 1981: 382-383; Kasprzak, 1986: 180.