The morphology and life-cycle of Trichobilharzia arcuata n. sp. (Schistosomatidae: Bilharziellinae) a nasal schistosome of water whistle ducks (Dendrocygna arcuata) in Australia

Summary The morphology and life-cycle of Trichobilharzia arcuata n. sp. from the nasal blood vessels of Dendrocygna arcuata from northern Australia are described. T. arcuata is distinguished from all species of Trichobilharzia except T. australis and African nasal schistosomes by its location in the nasal blood vessels and by the cercariae having 16 flame cells with a formula 2(3)+(4+1)] against 14 with a formula 2(3)+(3+1)], or 12 with a formula 2(3)+(2+1)] in the case of T. corvi. T. arcuata differs from the five African nasal schistosomes in the nature of the tegument, the position of the male genital papilla and the shape of the eggs and from T. australis in the position of the caecal reunion, the number of testes, the absence of spines on the ventral tegument between the ovary and the seminal receptacle, the shape of the eggs and the presence of two germinal masses in the miracidium. Lymnaea lessoni exposed to miracidia of T. arcuata developed patent infection in 22 to 41 days. Intramolluscan development of T. arcuata is similar to T. stagnicolae and T. physellae. Domestic Muscovy ducks and pigeons developed patent infections in 22 and 12 days respectively. Chickens, a black duck and a grey teal did not become infected. ac]19840616