Sound production mechanism in triggerfish (Balistidae): a synapomorphy

Abstract : The ability to produce sounds foracoustic communication is known in differentBalistidaespeciesbuttheeventualsynapomorphicaspectof the mechanism remains to be shown. In Rhinecanthus aculeatus, soundsresultfromalternatesweepingmovementsoftheright andleft pectoral fins, which push a system of three scutes against the swim bladder wall. In this study, we made a comparison between the sounds produced by this species and two additional ones (Balistapus undulatus and Rhinecanthus rectangulus) using hand-held specimens to provide a description of the sound mechanism. The results highlighted that the sound production mechanism is similar in the three species. According to recent phylogenetic data and shared morphological features, this mechanism could be common to the majority of Balistidae family members and all species could be capable of sound production using pectoral fins.