Molecular systematics of the freshwater stingrays (myliobatiformes: potamotrygonidae) of the Amazon, Orinoco, Magdalena, Esequibo, Caribbean, and Maracaibo basins (Colombia – Venezuela): evidence from three mitochondrial genes

Abstract

Lack of adequate information about the taxonomic and evolutionary relationships, ecology, biology, and distribution of several species belonging to the family Potamotrygonidae makes these species vulnerable to anthropic activities, including commercial overexploitation for the ornamental fish market. The aim of this study was to investigate the systematic relationships among genera and species belonging to this family by analyses of three mitochondrial gene regions. Samples were collected from the main river basins in Colombia and Venezuela for four genera and seven species of the family, as well as for what appear to be unidentified species. Three mitochondrial molecular markers COI, Cytb, and ATP6 were amplified and sequenced. Maximum likelihood and Bayesian inference analysis were performed to obtain topologies for each marker and for a concatenated dataset including the three genes. Small dataset may compromise some methods estimations of sequence divergence in the ATP6 marker. Monophyly of the four genera in Potamotrygonidae was confirmed and phylogenetic relationships among members of the Potamotrygon genus were not clearly resolved. However, results obtained with the molecular marker Cytb appear to offer a good starting point to differentiate among genera and species as a tool that could be used for barcoding. The application of this gene as a barcode could be applied for management and regulation of extraction practices for these genera. Sequencing complete mitochondrial genomes would be the next step for testing evolutionary hypothesis among these genera. Population structure analyses should be undertaken for Paratrygon, Potamotrygon magdalenae and motoro.

Keywords:

• Colombia
• conservation
• molecular systematics
• Potamotrygonidae
• Venezuela

Acknowledgements

The authors thank the IAvH, MHNLS (Fundación La Salle de Ciencias Naturales, Venezuela), the SINCHI institute in Puerto Leguizamo and the CDA Corporation in Inirida for helping us with sample collection, and Fundación Omacha for providing the samples from Puerto Carreño. The authors also thank D. Toffoli for providing the sequence of the ATP6 and COI primer.

Declaration of interest

No conflict of interest exists. Financial support for this project was provided by a scholarship to Garcia D. from “Iniciativa de Especies Amenazadas – IEA Convenio #10 2012” trough Fundación Omacha, from “Proyecto Semilla” from Facultad de Ciencias Universidad de los Andes and from the IAvH (through Carlos A. Lasso), as part of the annual operating work plans (2012–2013).

Supplementary material available online

Supplementary Table S1.