Cestodes of cestodes of Peruvian freshwater stingrays
Journal of Parasitology
2003
Journal Article
89
5
1018-1024
American siluriform fishes proteocephalidea eucestoda parasites Madre de Dios River aquatic habitats morphology phylogenetic analysis fish stingrays taxonomy Madre de Dios Bibliography
Adult tetraphyllidean tapeworms (Platyhelminthes: Eucestoda) from the spiral intestines of three species of potamotrygonid stingrays (Paratrygon aiereba, Potamotrygon castexi, and Polamoyrygon motoro) in the Madre de Dios river in Peru were found to host numerous cysts embedded in their parenchymal tissues. Histological sections of the cysts revealed the presence of a scolex bearing four suckers and in unarmed apical organ consistent with larval stages of both Cyclophyllidea and Proteocephalidea. To further elucidate their identities, partial 28S ribosomal DNA (rDNA) sequences were characterized from three cysts and four adult Rhinebothrium spp. 'host' worms and screened against all available cestode 28S rDNA data. Initial BLAST screening, and Subsequent alignment ruled out the possibility that the cysts were cyclophyllidean, and the cyst and adult sequences were thus aligned together with all available lecanicephalidean, litobothriidean, protcocephalidean, and tetraphyllidean sequences. Sequences from all three cysts were identical, and phylogenetic analysis clearly placed them among derived members of the Proteocephalidea. although no exact match was found. Sequences from the adult host worms formed two identical pairs and grouped together with other tetraphyllidean species from rays. These results are compared with records of hyperparasites of South American catfish cestodes. This is the first confirmed record of a proteoccphalidean cestode parasitizing a tetraphyllidean cestode.