Redescription of the giant mud worm Paraleonnates uschakovi Khlebovich and Wu, 1962 (Polychaeta: Nereididae) with special reference to the synonymy of Periserrula leucophryna Paik, 1977 and the difference from Paraleonnates bolus (Hutchings and Reid, 1991)

There has been a long-standing taxonomic confusion over the name of a giant nereidid worm living in Asian intertidalmud flats. To clear up the confusion, we examined the type specimens of Paraleonnates uschakovi Khlebovich and Wu,1962 described from China as well as Periserrula leucophryna Paik, 1977 described from Korea (Polychaeta: Nereididae),together with additional non-type materials newly collected from Korea, China, Taiwan, and Thailand. Our results con-firmed that Periserrula leucophryna should be reduced to a junior synonym of Paraleonnates uschakovi as previouslynoted, and that this species is widely distributed in Asia, newly recorded from Taiwan and Thailand. We also present newinformation about the arrangement of three kinds of chaetae in the parapodia as a characteristic of this species. We alsocompared this species with Paraleonnates bolus (Hutchings and Reid, 1991) described from Australia and concluded thatthese are different species. Based on our examination, we propose the amended diagnosis of the genus Paraleonnates Khlebovich and Wu, 1962. Paraleonnates Amoureux, 1985 erected as a monotypic genus for P. guadalupensis Amoureux,1985 was judged as a junior homonym of Paraleonnates Khlebovich and Wu, 1962, and P. guadalupensis is transferred to the genus Leonnates Kinberg, 1865.