The genus Argathona Stebbing, 1905 (Crustacea: Isopoda: Corallanidae) in Singapore marine waters, with description of two new species

The genus Argathona Stebbing, 1905 from Singapore waters is reviewed. Four species are reported, namely Argathona rhinoceros (Bleeker, 1857), Argathona aff. macronema, Argathona lineata, new species, and Argathona trichota, new species. The identity and synonymy of Argathona macronema (Bleeker, 1857) is briefly reviewed. Argathona lineata, new species, and Argathona trichota, new species, are both described and figured. An annotated list of all species in the genus Argathona is provided. Argathona lineata, new species, can be recognised by the elongate pentagonal frontal lamina 3.8 times longer than wide, posterior margins of pleonites 3-5 with transverse row of nodules, a sub-truncate pleotelson posterior margin and the dorsal surface of the pleotelson with two dense sub-median fields of acute hyaline setae, and the antennal flagellum extending to pereonite 4; fresh specimens show five or six longitudinal stripes of brown (or dark orange) chromatophores. Argathona trichota, new species, may be identified by the short frontal lamina (shorter than the posterior width), ovigerous females with the dorsum covered by dense hyaline setae, and the relatively short antennal flagellum extending to mid-pereonite 4.