A new genus of fish blood flukes (Aporocotylidae Odhner, 1912) is proposed for a species found on reefs surrounding Lizard Island on the northern Great Barrier Reef. Rhaphidotrema kiatkiongi gen. et sp. n. was recovered from the heart of the stars-and-stripes pufferfish, Arothron hispidus (L.) (Tetraodontidae). Rhaphidotrema kiatkiongi is notable as the first digenean reported to possess a penis stylet. It also differs from all other aporocotylid flukes in having a combination of 18-19 testes in a group at the ends of the intestinal caeca, a broad lanceolate body shape with a dextrally-directed posterior bend at the level of the male genital pore, and separate genital pores, with the female genital pore distinctly sinistral and the male genital pore slightly dextral to midline. This is the second species of aporocotylid fluke reported from this pufferfish.