Cestodes of Cestodes of Peruvian Freshwater Stingrays

Abstract

Adult tetraphyllidean tapeworms (Platyhelminthes: Eucestoda) from the spiral intestines of 3 species of potamotrygonid stingrays (Paratrygon aiereba, Potamotrygon castexi, and Portamotrygon 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 4 suckers and an 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 3 cysts and 4 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, proteocephalidean, and tetraphyllidean sequences. Sequences from all 3 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 2 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 proteocephalidean cestode parasitizing a tetraphyllidean cestode.

Redescription of Pseudanthobothrium hanseni Baer, 1956 and description of P. purtoni n. sp. (Cestoda: Tetraphyllidea) from different pairs of rajid skate hosts, with comments on the host-specificity of the genus in the northwest Atlantic

“…between sequences of Pseudanthobothrium specimens analysed from the different host species: erinacea, Leucoraja erinacea; ocellata, L. ocellata; radiata, Amblyraja radiata; senta, Malacoraja senta tools and challenges the dogma of the strict specificity of tetraphyllidean tapeworms, thus demonstrating the need to extend this type of study to other genera of the group. The low observed intraspecific T16-sequence (D2 variable domain) variation within species of Pseudanthobothrium (\0.31% in P. purtoni and \0.47% P. hanseni, including isolates from northeast and northwest Atlantic for the latter) is consistent with variation observed between individuals of other species of tetraphyllidean (Brickle et al, 2001;Reyda & Olson, 2003;Agusti et al, 2005;Randhawa et al, 2007). The 2.64-3.42% sequence divergence observed between the two Pseudanthobothrium spp.…”

Cryptic species ofDidymobothrium rudolphii(Cestoda: Spathebothriidea) from the sand sole,Solea lascaris, off the Portuguese coast, with an analysis of their molecules, morphology, ultrastructure and phylogeny

“…Two nuclear ribosomal regions were characterized: the large-subunit (lsrDNA) which has proven to be informative for both phylogenetic and diagnostic studies of the Cestoda (e.g. Brickle et al 2001 ;Olson et al 2001 ;Reyda and Olson, 2003 ;Agustí et al 2005 ;Aznar et al 2007) and the second internal transcribed spacer (ITS-2) which has been commonly used for investigating inter-and intraspecific variation in flatworms (e.g. Verneau et al 1997 ;Zehnder and de Chambrier, 2000 ;Olson et al 2002 ;see Olson andTkach, 2005 andNolan andCribb, 2005).…”

Digenea, Nematoda, Cestoda, and Acanthocephala, parasites in Potamotrygonidae (Chondrichthyes) from the upper Paraná River floodplain, states of Paraná and Mato Grosso do Sul, Brazil

“…The two formers are monospecific, while Potamotrygon has approximately 26 valid species (Carvalho et al 2003). Fifteen of these species have parasitological records, including the species of the present study, considering several regions: Salobra River (Paraguay River Basin, state of Mato Grosso, Brazil) (Rego 1979); vicinity of Corumbá (state of Mato Grosso do Sul, Brazil) (Brooks and Amato 1992); Amazonas River (Amazonas River Basin, Brazil) (Campbell et al 1999); Orinoco River delta (Orinoco River Basin, Venezuela) ; upper Madre de Dios River (Manu River Basin, Peru) (Reyda and Olson 2003).…”