Ciliated cells and chaetotaxy of the larvae of seven species of monocotylid monogeneans (Platyhelminthes) from Heron Island, Great Barrier Reef, Australia

The distribution and the number of ciliated cells and sensilla of the oncomiracidia of seven species representing five of the six subfamilies of monocotylid monogeneans are described. The species examined include Troglocephalus rhinobatidis Young, 1967 from the Dasybatotreminae; Decacotyle floridana (Pratt, 1910) Chisholm and Whittington, 1998 from the Decacotylinae; Heterocotyle capricornesis Chisholm and Whittington, 1996 and Neoheterocotyle rhinobatidis (Young, 1967) Chisholm, 1994 from the Heterocotylinae; Merizocotyle icopae Beverley-Burton and Williams, 1989 from the Merizocotylinae; and Clemacotyle australis Young, 1967 and Monocotyle spiremae Measures, Beverley-Burton and Williams, 1990 from the Monocotylinae. The number of ciliated cells in each zone (anterior, median and haptoral) is similar between the species, but the distribution of these cells varies and generally supports the subfamilial divisions proposed for the Monocotylidae on the basis of a phylogenetic analysis of morphological characters of the adults. A silver-staining technique modified from the method of Lambert is described.