Motoro stingray study reveals new fish parasite


A study of wild freshwater stingrays from the Amazon basin has revealed a new species of fish parasite.

Veronica Ivanov, a biologist from the University of Buenos Aires, found a new species of cestode parasite in the spiral intestines of wild caught Ocellated freshwater stingrays, Potamotrygon motoro.

Her findings, which have recently been reported in the Journal of Parasitology, describe the taxonomy and biology of the new stingray parasite, which is a member of the family Onchobothriidae.

The species, which Ivanov has named Acanthobothrium ramiroi, emphasises the diversity of stingrays in the Potamotrygonidae family, says Ivanov.

Other cestode parasites from the Acanthobothrium genus have already been recored from other species of freshwater stingray, but this new species is rather different.

Says Ivanov: "Acanthobothrium ramiroi n. sp. can be distinguished from all other congeners by the combination of the following characters: asymmetrical hooks (medial and lateral hooks conspicuously different in size and form, with axial prong of medial hooks stouter than abaxial prong), hook size (total length of medial hooks up to 242 microm, total length of lateral hooks up to 239 microm), bothridia not fused to the scolex proper at posterior ends, worm size (51-84 mm long), and the presence of a conspicuous vaginal sphincter."

The Motoro stingrays collected for the study were collected in the tributary rivers of the Parana River in Argentina.

For more details see the paper: Ivanov, VA (2005) - A new species of Acanthobothrium (Cestoda: Tetraphyllidea: Onchobothriidae) from the ocellate river stingray, Potamotrygon motoro (Chondrichthyes: Potamotrygonidae), in Argentina. Journal of Parasitology, 2005 Apr;91(2):390-6.