Pseudorhabdosynochus caledonicus is a small monogenean, 0.5 mm in length. 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. It has been described as "a heavily sclerotised ‘trumpet’, followed by sclerotised test-tube shaped cylinder, with heavily sclerotised structure associated laterally with cylinder and a lateral structure, roughly star-shaped, with small chamber communicating with lumen of cylinder". ==Etymology==