Amaterasia amanoiwatoi nov. gen., nov. sp. (Copepoda, Siphonostomatoida, Amaterasidae nov. fam.), with gall-forming juveniles parasitic on the fins of a balistid actinopterygian fish.

A parasitic copepod, Amaterasia amanoiwatoi nov. gen., nov. sp. (Siphonostomatoida, Amaterasidae nov. fam.) is described together with its juveniles, including the copepodid stages, based on specimens recovered from galls formed on the fins of the fish, Xanthichthys lineopunctatus (Hollard, 1854), taken off Clarion Island, eastern Pacific, in 1957. This species resembles pandarid copepods, but is distinct in some characteristic features. It has gall-forming juveniles in its life cycle, which are referred to here as encysted copepodid stage. An advanced encysted copepodid 5 yielded an adult female developing inside it, on which the description of this new species is based. The encysted copepodid encysts and lodges inside a gall, with its caudal rami extending partly beyond the posterior orifice of the gall. All stages found probably are females. The encysted copepodid ingests exudates from the host through a ventral hole in the cyst wall. The encysted copepodid 1 is compared with caligid and pandarid copepodids. Some speculations are made on the possible life history of this species. [ABSTRACT FROM AUTHOR]