Pseudorhabdosynochus hyphessometochus is a diplectanid monogenean parasitic on the gills of the yellowmouth grouper, Mycteroperca interstitialis.

The description by Kritsky, Bakenhaster & Adams in 2015 includes the following: Body flattened dorsoventrally, with broad cephalic region, trunk with nearly parallel lateral margins, and moderately long peduncle tapering posteriorly.

Pharynx subspherical; esophagus short to nonexistent; intestinal ceca blind, extending posteriorly into anterior portion of peduncle.

A second duct of unknown origin and function entering portal of male copulatory organ.

Male copulatory organ reniform, quadriloculate, with short tapered cone; walls of chambers comparatively thick; distal tube elongate; retractile filament not observed.

Germarium pyriform, dorsoventrally looping right intestinal cecum; Mehlis’ gland not observed; uterus delicate, with variable diameter.

Vitellarium absent in regions of other reproductive organs, otherwise dense throughout trunk and extending into anterior portion of peduncle.

It most closely resembles P. mycteropercae in the basic morphology of the male copulatory organ and haptoral sclerites but is distinguished from the latter species by having a vaginal sclerite with a smaller thick-walled chamber with a reduced cavity and a distal tube with a single recurve before its attachment to the vaginal vestibule.