Biota Neotrop., vol. 11, no. 4 Nuclear-follower foraging associations among Characiformes fishes and Potamotrygonidae rays in clean waters environments of Teles Pires and Xingu rivers basins, Midwest Brazil Domingos Garrone Neto1,3 & Lucélia Nobre Carvalho2 1Laboratório de Pesquisa de Elasmobrânquios, Universidade Estadual Paulista, Campus Experimental do Litoral, CEP 11330-900, São Vicente, SP, Brazil 2Núcleo de Estudos de Biodiversidade da Amazônia Mato-grossense – NEBAM, Instituto de Ciências Naturais, Humanas e Sociais – ICNHS, Universidade Federal do Mato Grosso – UFMT, CEP 78557-267, Sinop, Mato Grosso, MT, Brazil 3Corresponding author: Domingos Garrone Neto, e-mail:
[email protected]. GARRONE NETO, D. & CARVALHO, L.N. Nuclear-follower foraging associations among Characiformes fishes and Potamotrygonidae rays in clean waters environments of Teles Pires and Xingu rivers basins, Midwest Brazil. Biota Neotrop. 11(4): http://www.biotaneotropica.org.br/v11n4/en/abstract?short- communication+bn01511042011 Abstract: During under and overwater observations were recorded nuclear-follower foraging associations among three species of characiform fishes – Chalceus epakros, Hemiodus semitaeniatus and Hemiodus unimaculatus - and a freshwater stingray species - Potamotrygon orbignyi – in the Teles Pires and Xingu rivers basins, Midwest Brazil. The teleost fishes were observed closely following the stingrays during the behavior of stirring the substrate to uncover invertebrates, which cause discrete sediment clouds. Apparently this sediment perturbation attracts the fishes that approached the foraging stingrays to feed on small preys and other food types exposed this way. This is a typical example of a commensal relationship in which one participant is benefited while the other is unaffected, and represents the second published record of nuclear-follower feeding association between potamotrygonid rays and teleost fishes, demonstrating the potential of naturalistic studies in discovering new interactions involving species of freshwater fish.