An emended generic diagnosis for Cycloplectanum Oliver, 1968 (Monogenea: Diplectanidae) is provided which emphasizes the importance of the terminal genitalia (penis and vagina) in generic separation. Cycloplectanum americanum (Price, 1937) Oliver, 1968 is recognized as type species of Cycloplectanum. Cycloplectanum epinepheli (Yamaguti, 1938) n.comb., C. serrani (Yamaguti, 1953) n.comb., C. amplidiscatum (Bravo-Hollis, 1955) n.comb., C. latesi (Tripathi, 1955) n.comb., C. melanesiensis (Laird, 1958) n.comb., C. querni (Yamaguti, 1968) n.comb., C. cupatum (Young, 1969) n.comb., C. summanae (Young, 1969) n.comb., C. vagampullum (Young, 1969) n.comb., together with C. hongkongensis n.sp., C. lantauensis n.sp., and C. yamagutii nom.nov., are included in the genus. Cycloplectanum yamagutii nom.nov. is proposed for Pseudorhabdosynochus epinepheli which was named a synonym of C. americanum by G. Oliver in 1968.Based on material from Epinephelus spp. (Serranidae) taken in the South China Sea, redescriptions are presented for C. cupatum and C. vagampullum. In addition, C. hongkongensis n.sp. from E. brunneus and E. awoara and C. lantauensis n.sp. from E. brunneus and E. fario are proposed. The findings of C. cupatum and C. vagampullum on E. fario represent new host and geographic records.

Pterigodermatites (P.) spinicaudatis sp. n. from Dromiciops australis is proposed and described. The simple morphology of the ovijector and the presence of a well developed spine between the two cuticular projections at the caudal extremity of the female distinguish the studied nematode from the remainder species of the genus parasitizing South American Edentata, marsupials and cricetid rodents. The distribution area of the hosts of the different species of P. (P.) are given. The studied genus does not parasitize any Australian marsupials. It was found in the endemic South American Microbiotheriidae. This fact suggests from a parasitological point of view that D. australis is not related to the Australian marsupials but to the South American ones.

Travassostrongylus yungaensis n. sp. and Hoineffia simplicispicula n. sp., belonging to the family Viannaiidae and collected from the intestine of Thylamys venustus cinderellus and Lutreolina crassicaudata from Tucamfin and Salta, Argentina, are described. T. yungaensis n. sp. differs from T. tourei, T. quintus, T. quatuor and T. paraquintus because it possesses a well-developed dorsal lobe of the caudal bursa without accessory rays. Furthermore, the absence of a telamon distinguishes it from T. quatuor and T. quintus. H. simplicispicula differs from H. cayennensis in its shorter cephalic vesicle, simple spicular structure and gubernaculum, the absence of accessory pieces in the caudal extremity of the female and the lack of ornamentation between rays 2 and 6 and the dorsal lobe of the male. The distribution of the parasites along the intestine of the host suggest that both genera may co-exist, sharing the same ecological habitat but each having its preferential microbiotope.

The new subfamily Interniloculinae, characterized by the presence of four testes, the position of the vagina, lack of eye spots, and the anatomy of the haptor with 14 peripheral and three internal loculi is placed in the family Capsalidae Baird, 1853. Consequently, the familial diagnosis of Bychowsky 1957 is emended. Interniloculus chilensis is the type genus and species of this newly proposed subfamily. The parasite was found on the gills of Helicolenus lengerichi (chancharro), a bottom-dwelling teleost from the coastal waters of central Chile.

Neohilgertia gen. n. proposed for Oxyuridae nematodes from Thylamys venustus cinderellus (Marsupialia: Didelphidae) is described. The hypothesis about the possibility of a secondary parasitism for marsupials and the origin of the genus in the African Sciuridae parasite ancestors is discussed