Feeding behavior of the Neotropical freshwater stingray potamotrygon motoro (Elasmobranchii: Potamotrygonidae)

Abstract

The feeding mechanisms of elasmobranchs and their functioning have been receiving growing scientific attention, although less emphasis has yet to be directed towards batoid species. The present study investigated the use of orobranchial musculature during prey capture and processing behavior in Potamotrygon motoro. Ten orobranchial muscle groups were removed to determine their relative biomasses. The kinematics of the musculature was described based on videos of prey capture and manipulation under captive conditions recorded at 250 and 500 field/s. Analyses of the orobranchial musculature indicated that adductor muscles responsible for closing the mouth had high biomasses, which is consistent with their functions related to apprehend and manipulate the prey. The feeding behavior adopted by this ray species showed a sequence of manipulation to crush hard prey as crustaceans (dominant prey category for P. motoro) to facilitate final oral transport. The morphological and behavioral characteristics of P. motoro are essential to fully understanding the mechanisms used in prey capture and processing in environments in which these stingrays occur. © 2012 Sociedade Brasileira de Ictiologia.