Bicentenariellan. g. is proposed to accommodate three new species of dactylogyrid monogeneans found on the gills of the threadfin bass Pronotogrammus multifasciatus Gill (Perciformes: Serranidae) from the Southeastern Pacific Ocean off Peru: Bicentenariella claudiaen. sp. (type-species), B. sinuosan. sp. and B. puertopizarroensisn. sp.Bicentenariellan. g. is mainly characterised by possessing a broadly X-shaped dorsal bar, which has the anterior arms longer than posterior ones and by having a ventral bar with two medial projections. Bicentenariellan. g. is also characterised by having: (i) anchors equal, each with elongate superficial root and short deep root; (ii) an haptor with bilaterally paired lobes, lacking haptoral reservoirs; (iii) hooks with protruded obtuse thumb and undilated shank; (iv) a tubular tapered-shaped male copulatory organ with basal flap bifurcated or not (MCO), lacking accessory piece; (v) a delicate membrane associated with the shaft of the MCO present or absent; (vi) a muscular trumpet-shaped vagina, vaginal aperture dextrolateral; (vii) eyespots absent, accessory chromatic granules present; and (viii) a not lobulated testis. Bicentenariella claudiaen. sp. is characterised by having a MCO with whip-shaped distal end and a rod-shaped ventral bar with hatchet-shaped lateral ends. Bicentenariella sinuosan. sp. is typified by possessing a MCO with an irregular filamentous membrane surrounding its shaft and a dumbbell-shaped ventral bar. Bicentenariella puertopizarroensisn. sp. can be differentiated from its congeners by having a tubular-shaped MCO with twisted distal end and a narrow W-shaped ventral bar. Parancylodiscoides peruensis Cruces, Chero, Sáez & Luque, 2017 from Hemanthias peruanus (Steindachner) and P. signiferi Cruces, Chero, Sáez & Luque, 2017 from H. signifer (Garman), are transferred to Bicentenariellan. g. as B. peruensisn. comb and B. signiferin. comb., respectively.