Chaetotaxy of Newly Excysted Metacercariae among Five Species of Thai Paragonimus

Abstract

Scanning electron microscopy was used to study the papillae distribution (chaetotaxy) among fi ve species of newly excysted Paragonimus metacercariae (P. bangkokensis, P. harinasutai, P. heterotremus, P. siamensis, and P. westermani). Comparative data on the distribution of papillae in these species indicate considerable differences in the arrangement of papillae on the surfaces of the oral and ventral suckers. The numbers of papillae in the mouth of the oral sucker should be used to differentiate these species. A key to the species of Thai Paragonimus excysted metacercariae is given.