Trimusculotrema heronensis sp. nov. is described from the skin of the pink whipray, Himantura fai, caught at Heron Island on the Great Barrier Reef, Queensland, Australia. The parasite differs from its closest relative, T. uarnaki, by its greater size and by features of the cirrus. There is evidence that the haptor of T. heronensis secretes cement. The living parasite is unable to swim. Whether Trimusculotrema spp. are benedeniines or entobdellines is discussed.