Aporrectodea caliginosa (Savigny, 1826)
Description - External - Body length 50 -150 mm, diameter 2-4 mm, 100 -180 segments. Colour usually brown, sometimes greenish. Some pigmentation almost always present, at least dorsad at the front of the body. Head epilobous, first dorsal pore between 5/6-9/10 . Glandular tumescence usually on (9)10 -12 ab. Setae closely paired, setal arrangement after the clitellum: aa:ab:bc:cd:dd= x:x:x:x:x. Clitellum extends on segments 25, 26, (29)-34, 35 saddle-shaped. Tubercles on 31-33 as two pair of scale-like protuberances, or a continuous pad-like organ, but all of the transitory stages could be fund. Male pore on 15, great slit between setae b-c, surrounded by a glandular crescent, frequently protruding into the neighboring segments.
Internal - Dissepiments 5/6-9/10 moderately thickened. Crop in 15-16, gizzards in 17-18. Two pairs of testes free in 10 , 11, and four pairs of seminal vesicles in 9-12. Receptaculae seminis two pairs in 9/10 , 10 /11 open in setal line cd. Calciferous glands in 10 -12 with lateral pouches in 10 . Excretory system holonephridial with "S" shaped nephridial bladders, hook backwards. The cross section of longitudinal muscle layer are of pennate type.
This species is one of the most widely distributed earthworm with different partenogenetic and polyploid morphs described as separate species.
Distribution - Ap. caliginosa is a typical synanthrop species. It thrives in pastures, gardens and forest as well. It could be found in every type of substrate even in the poorest sandy soil. As adapted to live in a disturbed environment it could displace native worms if introduced. According to the Bouche's ecological characterization Ap. caliginosa belongs to the endogeic group, living and feeding in the mineral soil layer. This species is native in the Palearctic, but it has been introduced extratropically all over the world.