LIGHT AND SCANNING ELECTRON MICROSCOPIC OBSERVATIONS OF THE CERCARIAE AND REDIAE OF RIBEIROIA ONDATRAE

Abstract

Ribeiroia ondatrae (Price, 1931) is a digenetic trematode occurring in lentic aquatic systems throughout North and South America and has been identified as a cause of limb malformations in numerous species of amphibians. Several questions still remain related to basic morphology of the various life stages of R. ondotrae. The purpose of this study was to describe the daughter rediae and cercariae of R. ondatrae using light and scanning electron microscopy. Helisoma trivolvis snails infected with R. ondatrae were collected from Delaware Lake, NJ. Daughter rediae and cercariae were collected from the infected snails, and light and scanning electron microscopy were used to describe the life stages with particular focus on the tegumentary surface. The tegument of R. ondatrae rediae and cercariae is aspinose despite reports in the literature describing a spinose tegument in the cercariae. The rediae and cercariae were observed to be much simpler in tegumentary structure than various species of Echinostoma that have been studied recently with scanning electron microscopy.