Protocotyle euzetmaillardi Justine, 2011 is a species of monogenean of the family Hexabothriidae Price, 1942. It is the third described species of the genus Protocotyle, after Protocotyle grisea (Cerfontaine,1899) Euzet & Maillard, 1974 and Protocotyle taschenbergi (Maillard & Oliver,1966) Euzet & Maillard, 1974.The body is 4.5-6.1 millimetres in length, elongate, and it includes, like all monogeneans, a posterior attachment organ called haptor. The haptor is symmetrical, armed with six suckers, each provided with one hook-shaped sclerite, and there is a lateral appendix bearing a single pair of terminal suckers and a single pair of hooks (also called hamuli). There is a single ovary, located at mid-length of the body, and numerous testes, more posterior. The oötype wall has longitudinal r