Nematode isolation from Creophilus maxillosus (L.) (Staphilinidae) with a description of Rhabditidoides eutrophicola n. sp. (Diplogastridae) and some notes on Diplogastrellus gracilis (Bütschli, 1876) Paramonov, 1952 (Diplogastridae)

Summary Nematodes associated with the carcass beetle Creophilus maxillosus were examined. The beetles were collected from the decomposed body of a dead racoon dog Nyctereutes procyonoides in Kyoto, Japan, and dissected for examination of internal parasites. The dissected beetles were kept on agar plates for isolation of phoretic species. Although no parasites were found, three species of phoretic associates, Caenorhabditis plicata , Diplogastrellus cf. gracilis and Rhabditidoides sp., were recognised, and two species were later successfully cultured as laboratory strains. Diplogastrellus cf. gracilis and Rhabditidoides sp. were compared to an authentic strain of D. gracilis (German strain, SB306) and two presumably conspecific strains (German strain RS5443 and Japanese strain NKZ346), respectively, by mating experiments and molecular sequence comparison. The comparisons revealed that D. cf. gracilis is conspecific to D. gracilis SB306, and three Rhabditidoides strains are new conspecific species. The typological and molecular characters of D. gracilis are described and compared with other populations of the species, and Rhabditidoides sp. is taxonomically described as Rhabditidoides eutrophicola n. sp.