A DNA-based demonstration of a three-host life-cycle for the Bivesiculidae (Platyhelminthes: Digenea)

Abstract

Immature bivesiculid trematodes collected from the intestine of Thalassomalunare (Labridae) are shown to be morphologically consistent with adults of Bivesiculaclaviformis from Epinephelus fasciatus (Serranidae). In addition, the immature bivesiculids have the same sequence for the second internal transcribed spacer of the ribosomal DNA. Comparison with three other species of Bivesiculidae showed differences of between 23% and 30%. These results show that bivesiculids may have three-host life-cycles in addition to the two-host life-cycles that have been demonstrated previously. The three-host life-cycle enables bivesiculids to infect large carnivorous fishes.