Redescription of the female of Mexiconema liobagri (Nematoda: Daniconematidae), a little-known parasite of the rare endemic catfish Liobagrus reinii (Amblycipitidae), in Japan

Gravid females of the little-known dracunculoid nematode Mexiconema liobagri Moravec et Nagasawa, 1998 (Daniconematidae), a parasite of the rare endemic catfish Liobagrus reinii Hilgendorf (Amblycipitidae), were found in the body cavity of this fish from two new localities in Japan: the Takami River at Kotsugawa, Higashiyoshino, Nara Prefecture and the Tenryu River at Ina, Nagano Prefecture, representing the second record of this nematode species since its original description. Light and scanning electron microscopical examinations of these specimens enabled us to supplement the original description of M. liobagri and to recognise biometrical variability in this species. Details of the cephalic structure of M. liobagri (presence of the small triangular mouth armed with six denticles, surrounded by a pair of large lateral amphids and four submedian pairs of small cephalic papillae) are described for the first time. In addition to M. liobagri, another specific nematode parasite, Rhabdochona japonica Moravec, 1975, was recorded in the intestine of L. reinii from the Takami River.