Acanthobothrium Blanchard, 1948 from the northwest Atlantic and their phylogenetic relationships with freshwater lineages

• Autor(a) principal: Golfetti, Yu
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: http://www.teses.usp.br/teses/disponiveis/41/41133/tde-01032019-083159/
• topic: Biogeografia; Biogeography; Co-evolution; Coevolução; Especficidade; Host specficity; Neotropical; Neotropical; Sample size; Tamanho amostral

Parasite documentation has been an important tool to understand host history and co-evolutionary processes in these associations. Acanthobothrium is a worldwide genus of cestodes, and it is a parasite of sharks, skates and rays, with almost 200 nominal species. Recent studies are presenting new hypotheses on cestodes distribution and host specificity patterns. Due to their large distribution, geographical and in host taxa, Acanthobothrium seems to be a good model to evaluate these hypothesis. The Bay of Marajó is an estuarine area were freshwater stingrays of the family Potamotrygonidae share the same environment with marine dasyatid rays. There is no documentation about the dasyatid fauna of Acanthobothrium for Bay of Marajó, neither their relationships with freshwater lineages or their hosts. In our goal to understand those evolutionary events, our results revealed six new lineages of Acanthobothrium, parasites of Hypanus guttatus and Fontitrygon geijskesi, of which four are formally described. Five of those new lineages are included in a clade exclusive to Northwest Atlantic and Caribbean Sea. Acanthobothrium sp. 10 was recovered as sister of clade formed by marine Acanthobothrium sp. 9 sensu Trevisan and freshwater Acanthobothrium sp. 2 sensu Cardoso Jr. The specificity pattern of Acanthobothrium has been discussed and our results corroborate this discussion when we observed four species of Acanthobothrium sharing two different hosts of different genera. Also, host sample size may be correlated with the specificity and strict specificity patterns of the parasite to their hosts. The absence of Fontitrygon colarensis in our samples and the incongruities in comparison to Hypanus guttatus make us question the taxonomic status of F. Colarensis