Phylogeography and conservation genetics of the Amazonian freshwater stingray Paratrygon aiereba Müller &amp; Henle, 1841 (Chondrichthyes: Potamotrygonidae)

Renata G Frederico,Maria Lúcia Góes De Araújo,José A Alves-Gomes,Patricia Charvet-Almeida,Izeni P Farias

doi:10.1590/s1679-62252012000100007

Abstract

The family Potamotrygonidae is monophyletic comprising three genera: Paratrygon Duméril, Potamotrygon Garman and Plesiotrygon Rosa, Castello & Thorson. The distribution of most species in this family is restricted to a single basin or fluvial system. Only Potamotrygon motoro, Potamotrygon orbignyi and Paratrygon aiereba are found in more than one river basin. In this study we investigate genetic structuring of Paratrygon aiereba, from five rivers of the Amazon region: Negro, Solimões-Amazon-Estuary system, Tapajós, Xingu and Araguaia. Sixty-three individuals were sequenced for ATPase 6, and a representative subsample of 27 individuals was sequenced for COI. The COI dataset analysis indicated that Paratrygon is sister to all other potamotrygonid genera and species. Population parameters inferred from the analysis of ATPase 6 sequences revealed that the populations of this species are structured within each river, with no or nearly non-existent gene flow occurring between rivers and a positive correlation between geographic and genetic distances. Paratrygon aiereba is comprised of three geographically restricted clades with K2P interclade distances of at least 2%. Intraspecific divergence within P. aiereba is similar to the interspecific divergence observed in Potamotrygon spp. sampled throughout the same geographic area. Using the premises of COI barcoding and the allopatric distribution of the three P. aiereba clades, the taxon P. aiereba most likely comprises three distinct biological species. Since freshwater stingrays of the family Potamotrygonidae are highly exploited for the aquarium trade, management and conservation strategies need to be implemented at the level of each river basin, rather than at the level of the Amazon basin.

Highlights

Phylogeography deals with principles and processes governing the geographic distributions of genealogical lineages (Avise, 2000)
A growing number of studies have demonstrated that interspecific genetic distances observed between the cytochrome oxidase I (COI) mtDNA fragments is generally higher than 2%, which allows the differentiation of species that are more closely related and enables identification with a high degree of confidence
Due to its wide distribution, which ranges from the Orinoco River basin to the Amazon River basin, number of researchers have suggested that it a species complex (Charvett-Almeida, pers. comm.)

Summary

Introduction

Phylogeography deals with principles and processes governing the geographic distributions of genealogical lineages (Avise, 2000). These analyses are aimed at investigating patterns of geographic distribution of taxa and understanding processes that have resulted in these patterns (Bermingham & Moritz, 1998). The Neotropical region has been the object of a large number of biogeographic studies on fishes. The complex geomorphological history of this region is reflected in its ichthyofauna, which provides a rich source of material for the study of the Neotropical biogeography (Vari & Malabarba, 1998). Many studies have been carried out with the aim of discovering these biogeographic patterns and interpreting these patterns in light of geomorphological processes such as the formation of hydrographic basins. Examples include studies of the genera Brachyhypopomus, Pimelodella, and Roeboides in Central America (Bermingham & Martin, 1998), fishes of the Neotropical family Rivulidae (Hrbek & Larson, 1999), Potamorraphis in the river basins of the Amazon and Orinoco (Lovejoy & de Araújo, 2000), Prochilodus in the Amazon, Orinoco, and Paraná River basins (Sivasundar et al, 2001), Leporinus in the Paraná River Basin (Martins et al, 2003), Hypostomus in the main river basins of the Neotropics (Montoya-Burgos, 2003), Brachyplatystoma in the Solimões-Amazon-Estuary system (Batista et al, 2004; Batista & Alves-Gomes, 2006), Arapaima gigas in the Amazon River basin (Hrbek et al, 2005), Cichla in the Orinoco and Amazon River basins (Willis et al, 2007), Symphysodon in the Amazon River basin (Farias & Hrbek, 2008) and fishes of the order Characiformes in the main river basins of South America (Hubert & Renno, 2006)

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Conclusion