Pseudorhabdosynochus argus

Pseudorhabdosynochus argus is a small monogenean. The species has the general characteristics of other species of Pseudorhabdosynochus, with a flat body and a posterior haptor, which is the organ by which the monogenean attaches itself to the gill of is host. The haptor bears two squamodiscs, one ventral and one dorsal. The sclerotized male copulatory organ, or "quadriloculate organ", has the shape of a bean with four internal chambers, as in other species of Pseudorhabdosynochus. The vagina includes a sclerotized part, which is a complex structure.

The grouper Cephalopholis argus is the type-host of Pseudorhabdosynochus argus. The type-locality is the barrier reef off Nouméa, New Caledonia. The parasite has also been found in the same fish species near Heron Island, off Australia.