Pseudorhabdosynochus summanoides n. sp. (Monogenea: Diplectanidae) from Epinephelus coioides in Dapeng Bay, South China Sea, with observations on several similar species of Pseudorhabdosynochus Yamaguti, 1958.

One new species of diplectanid monogenean, Pseudorhabdosynochus summanoides n. sp., is reported and described from the marine fish Epinephelus coioides off Nan'ao Shenzhen, China. P. summanoides differs from its closest relative, P. summanae (Young, 1968), by the shape of its vaginal hard-parts, which have a tightly twisted distal region and an accessory patch on the proximal curve. During the course of this work, type-material of several species of Pseudorhabdosynochus was examined and aspects of the vagina and haptor are redescribed and/or figured. These species include P. americanus (Price, 1937), P. hargisi (Oliver & Paperna, 1984), P. amplidiscatus (Bravo-Hollis, 1954), P. epinepheli (Yamaguti, 1938), P. riouxi (Oliver 1986), P. melanesiensis (Laird, 1958), P. cupatus (Young, 1969), P. bocquetae (Oliver & Paperna, 1984), P. kritskyi Dyer et al., 1995, P. capurroi Vidal-Martinez, 1998, P. querni (Yamaguti, 1968) and P. summanae (Young, 1969). Several closely related species are considered in terms of their conspecificity: P. hargisi is proposed as a junior synonym of P. americanus; P. capurroi is suggested as a likely synonym of P. kritskyi; and it is suggested that P. cupatus and P. bocquetae may eventually be demonstrated to be consepcific with P. melanesiensis.