There has been a long-standing taxonomic confusion over the name of a giant nereidid worm living in Asian intertidal mud 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 confirmed that
Periserrula leucophryna should be reduced to a junior synonym of
Paraleonnates uschakovi as previously noted, and that this species is widely distributed in Asia, newly recorded from Taiwan and Thailand. We also present new information about the arrangement of three kinds of chaetae in the parapodia as a characteristic of this species. We also compared this species with
Paraleonnates bolus (Hutchings and Reid, 1991) described from Australia and concluded that these 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.