Haliotrema macrobaculum Zhukov, 1983 is transferred to Parancylodiscoides as P. macrobaculum (Zhukov, 1983) n. comb. (Monogenoidea: Dactylogyridae). The species is redescribed from the gills of gag Mycteroperca microlepis and is newly recorded from scamp Mycteroperca phenax and yellowmouth grouper Mycteroperca interstitialis (all Serranidae: Epinephelinae: Epinephelini) in the northern Gulf of Mexico. The transfer of H. macrobaculum to Parancylodiscoides is based on the presence of a dorsal bar with bifurcated ends, the hook morphology, the germarium lying to the right of the anterior end of the testis, and by the absence of an accessory piece in the copulatory complex. The generic diagnosis of Parancylodiscoides is emended to include species having a dextroventral or dextrolateral vaginal aperture.