Allopseudaxine katsuwonis

The body of Allopseudaxine katsuwonis comprises an anterior part attenuated in the cephalic region which contains most organs, and a posterior part called the haptor. The haptor bears a single row of 24 pedunculate clamps. The clamps of the haptor attach the animal to the gill of the fish. A lobe lappet is present, and is armed with two pairs of hooks. There are also two buccal suckers at the anterior extremity. The digestive organs include an anterior mouth, an oval pharynx, a simple oesophagus and a posterior intestine that bifurcates at or near level of genital pore in two lateral branches. The intestinal branches terminate in the distal portion of the haptor region. Each adult contains male and female reproductive organs. The reproductive organs include an anterior genital atrium armed with a corona of 14 hook-like spines, one row of dorsolateral marginal vaginae on each side of the body, each row divided into a longitudinal row of transverse slit with sclerotized margins, a slender tubular ovary and about 60 large oval testes pre, para and post-ovarian.^[1][8]

The type-host is the Skipjack-tuna Katsuwonus vagans,^[2] (currently named Katsuwonus pelamis)^[4] (Scombridae). The type locality is off Japan.^[2] It was also recorded of Hawaii.^[8]