Four new terrestrial species of Marionina (Clitellata, Enchytraeidae) fromChina and re-examination of M. hoVbaueri Moller

Enchytraeid surveys were made in China, mainly along the Changjiang (Yangtz e) River Basin, during the period 1991-1999. Among the findings, four terre strial species of Marionina are new to science and well illustrate the taxo nomic complexity of the genus as currently defined. Marionina sinica sp. n. is characterized by a specific chaetal distribution, the marionine pattern of the dorsal blood vessel, and elongate, fusiform, spermathecal ectal duc ts. Marionina sacculata sp. n. is distinguished by the possession of a pair of pouch-like oesophageal appendages in IV, the lack of lateral chaetae in VII-XI, a marionine pattern of the dorsal blood vessel, and short spermath ecal ectal ducts gradually expanding into spherical ampullae. Both M. sinic a and M. sacculata have minute bodies (2-3 mm long in vivo) and lack sperma thecal accessory glands. The former species shows its closest aYnities with the European M. brendae Rota, 1995, whereas the latter is closest to the G erman M. hoVbaueri Moller, 1971, for which an amended diagnosis is provided . Marionina seminuda sp. n. has only ventral chaetal bundles, distributed f rom III onwards and bisetose. It is similar to the Holarctic M. subterranea (Knollner, 1935) in lacking entirely the lateral chaetae and in having the brain incised posteriorly, the dorsal vessel bifurcating behind the pharyn x, and coelomocytes containing opaque granules, but diVers from it in havin g the longest chaetae in preclitellar segments and gland cells distributed all over the spermathecal ectal ducts. Marionina righiana sp. n. is diagnos ed by the location of the head pore on the prostomium, the absence of later al chaetae from VIII ( VII or IX) onwards, the possession of free spermathe cae extending backwards through one to four segments, the brain deeply inci sed posteriorly, the lumbricilline pattern of the dorsal blood vessel, and the opacity of coelomocytes in vivo. Prior to this study, members of the ge nus so atypical as M. righiana with respect to the position of the head por e and the structure of the spermathecae were known only from South American soils. Until the taxonomy of Marionina has been more thoroughly assessed a nd revised, the assignment of the four species to this large assemblage sho uld be regarded as tentative.