Grillotia epinepheli sp.n. is described on the basis of plerocerci found in the body cavity and peritoneum of the teleost, Epinephelus guaza (L.) (Perciformes: Serranidae) caught off Sardinia, Italy. The species is distinguished from congeners by its tentacular armament, particularly in the basal armature. The metabasal region is armed with rows of 8-9 principal hooks beginning on the internal face; hooks 9 (9’), if present, much smaller than hooks 8 (8’) and similar to minute hooks on the external face. There are three intercalary rows consisting of 3, 2 and 4 hooks each. The external face is armed with a longitudinal band of minute hooks arranged in about 4 files. Basal armature well developed and composed of 7-8 rows of falciform and spiniform hooks.