Acanthobothrium Blanchard, 1848: phylogenetic diversity of the linages that parasitize freshwater stingrays

Author(s)

Denis Jacob Machado

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2012-07-24

Examining board members

Fernando Portella de Luna Marques; Marcus Vinicius Domingues; Taran Grant

• Advisor: Fernando Portella de Luna Marques

Abstract

First we clarify some major points in the taxonomic history of Acanthobothrium. The authorship of the genus must be given to Blanchard in 1848, ocasion in which its first species, Acanthobothrium coronatum, was created. Therefore, the type species of Acanthobothrium is A. coronatum Blanchard, 1848, a junior synonym of A. corollatum (Abildgaard, 1790). Both Acanthothrothrium and A. corollatum have their concepts attached to armed tapeworms parasites of Raja batis L., their type host. Following we provided a phylogenetic analysis based on the direct optimization of 16S, 28S, and ITS1 rDNA to access the phylogentic position of freshwater Acanthobothrium lineages. The current morphological delimitations of Acanthobothrium sp. 1, Acanthobothrium sp. 2, A. terezae (syn. A. ramiroi) and A. quinonesi (syn. A. regoi and A. peruviense) are corroborated. There are indications that A. amazonensis should be considered synonym of A. quinonesi. Our results provide additionl evidence to support the idea that freshwater lineages of tetraphyllideans (as opposed to marine tetraphyllideans) presents great intra-specific morphological variation and low host specificity. Acanthobothrium quinonesi is sister group of a clade that comprises A. terezae and Acanthobothrium sp. 1. Acanthobothrium sp. 2 is more related to marine species of Acanthobothrium than to freshwater congenerics. This suggests that the colonization of the freshwater system by Acanthobothrium is likely to have occur via at least two separate lineages of Acanthobothrium infecting the exclusive common ancestor of the potamotrygonids, which would in time be responsible for the existence of two distinct clades of freshwater species of Acanthobothrium. (AU)

• FAPESP's process: 09/13561-5 - Phylogenetic diversity the lineages of Acanthobothrium van Beneden, 1850 (Eucestoda: Tetraphyllidea: Onchobothriidae) parasites of Potamotrygonidae (Chondrichthyes: Myliobatoidei)
• Grantee: Denis Jacob Machado
• Support Opportunities: Scholarships in Brazil - Master