Abstract
Four new and one known species of Belondiroidea Thorne, Citation1939 are reported from Japan. Axonchium mizukuboi sp. nov. has isthmus-like constriction between two parts of pharynx; rectangular pars refringens vaginae; spicules with thickened distal end; seven ventromedian supplements starting above the range of spicules and hemispheroid tail. Axonchium japonicum sp. nov. also has short isthmus-like structure between two parts of pharynx; triangular pars refringens vaginae; massive spicules with thickened distal tip and 9–10 ventromedian supplements. Dorylaimellus (D.) japonicus sp. nov. has 0.9–1.0 mm long body; poorly flanged odontophore; pharyngeal expansion 54–65% of neck length; 22–25 μm long, strongly ventrally arcuate spicules; four ventromedian supplements and elongate conoid tail with subacute terminus. Dorylaimellus (Axodorylaimellus) paracrassidens sp. nov. has 0.4–0.5 mm long body; slender odontostyle; pharyngeal expansion 48–57% of neck length; transverse vulva; long prerectum and short conoid tail. Axonchium amplicolle Cobb, Citation1920 is reported for the first time from Japan.
Acknowledgements
The authors are thankful to Dr T. Mizukubo for kindly providing nematode specimens from his collection. Part of this work was carried out when the first author was working at the National Agricultural Research Centre, Tsukuba, Japan as a JSPS invitation Fellow.