In the original description, MacCallum stated that the specimens were so much alike and he hesitated to describe them as separate species.

[1] Dillon & Hargis redescribed and illustrated Microcotyle pomacanthi from the gills of the grass porgy Calamus arctifrons (Sparidae) off Florida, noted slight differences in the atrial spines and suggested that further study may show that MacCallum's (1915) description included more than one species, as he suggested.

The reproductive organs include an anterior genital atrium opening just behind the bifurcation, armed with numerous spines, a medio-dorsal vagina, a single ovary, a somewhat indefinite elongated sac crossing the middle of the body and extending backward, and 18-27 testes which are posterior to the ovary.

The eggs are provided posteriorly with a rather stout tapering prolongation, anteriorly with a similar elongated structure.

[1] Microcotyle pomacanthi was described from specimens recovered from the gray angelfish Pomocanthus arcuatus (Pomacanthidae), the spotfin butterflyfish Chaetodon ocellatus and the foureye butterflyfish Chaetodon capistratus (Chaetodontidae), the porkfish Anisotremus virginicus (Haemulidae), the yellowedge grouper Hyporthodus flavolimbatus (referred to as Epinephelus flavolimbatusin the original description) (Serranidae), the Spanish hogfish Bodianus rufus (Labridae) (referred to as Harpe rufa in the original description) [1] and the grass porgy Calamus arctifrons (Sparidae).