Mesenchytraeus anisodiverticulus, a new enchytraeid with enlarged ventral chaetae (Annelida, Clitellata) from north-eastern China

摘要

Mesenchytraeus anisodiverticulus sp. nov. is described from north-eastern China. It is characterized by (1) enlarged ventral chaetae in segments V–VI (two per bundle); (2) nephridia with relatively developed interstitial tissue, occurring in five pairs in the preclitellar region; (3) a seminal vesicle occupying X–XVII, containing bulk of naked sperm bundles; (4) each spermatheca possessing two asymmetrical diverticula, attached entally to oesophagus in segment V; (5) atrium cylindrical, devoid of prostate glands and distinct from vas deferens; and (6) well-developed egg sac (extending to XVI, sometimes to XXI–XXIII).