The taxonomy and biology of the Polystomatidae (Monogenea) in Australian freshwater turtles (Chelidae,Pleurodira)

Polystomoides scottae n. sp. is described from the urinary and accessory bladders of Chelodina expansa. Four species of Neopolystoma are described from the conjunctival sacs of Australian freshwater turtles (Chelidae): Neopolystoma cribbi n. sp. from Emydura signata, E. macquarii, Elseya latisternum and Chelodina expansa; Neopolystoma spratti n. sp. from Chelodina longicollis; Neopolystoma tinsleyi n. sp. from Chelodina expansa; and Neopolystoma queenslandensis n. sp. from Emydura signata and E. macquarii. Polystomoides australiensis, Neopolystoma macleayi and N. chelodinae are redescribed from new individuals. Neopolystoma australis is made a junior synonym of N. kreffti. P. australiensis, N. macleayi and N. cribbi produced on average 5·6, 4·3 and 0·7 eggs per day, respectively. Eggs of P. australiensis take 33–57 days at 18–24°C and 30–33 days at 24–28°C to develop and hatch. Oncomiracidia of P. australiensis and N. macleayi had 64 ciliated cells; the patterns of the ciliated cells are the same for both species. Different sizes of worms in different sites in the hosts suggest strongly that the oncomiracidia of P. australiensis and N. macleayi enter the host, migrate to the ureters, possibly to the kidneys, then to the urinary bladder and finally to either the accessory bladders or cloaca. Successful cross-infection experiments between host genera (Emydura to Elseya) indicated that P. australiensis and N. macleayi have a low degree of host specificity.