title: New insights into the role of the pharyngeal jaw apparatus in the sound-producing mechanism of Haemulon flavolineatum (Haemulidae).
abstract: Grunts are fish that are well known to vocalize, but how they produce their grunting sounds has not been clearly identified. In addition to characterizing acoustic signals and hearing in the French grunt Haemulon flavolineatum, the present study investigates the sound-production mechanism of this species by means of high-speed X-ray videos and scanning electron microscopy of the pharyngeal jaw apparatus. Vocalizations consist of a series of stridulatory sounds: grunts lasting ~47 ms with a mean period of 155 ms and a dominant frequency of ~700 Hz. Auditory capacity was determined to range from 100 to 600 Hz, with greatest sensitivity at 300 Hz (105.0±11.8 dB re. 1 μPa). This suggests that hearing is not tuned exclusively to detect the sounds of conspecifics. High-speed X-ray videos revealed how pharyngeal jaws move during sound production. Traces of erosion on teeth in the fourth ceratobranchial arch suggest that they are also involved in sound production. The similarity of motor patterns of the upper and lower pharyngeal jaws between food processing and sound production indicates that calling is an exaptation of the food-processing mechanism.
authors.affiliation: Laboratory of Functional and Evolutionary Morphology, AFFISH-RC, University of Liège, 4000 Liège 1, Belgium f.bertucci@student.ulg.ac.be.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bertucci
authors.affiliation: Laboratory of Functional and Evolutionary Morphology, AFFISH-RC, University of Liège, 4000 Liège 1, Belgium Laboratory for Functional Morphology, University of Antwerp, 2610 Wilrijk, Belgium Evolutionary Morphology of Vertebrates, University of Ghent, 9000 Ghent, Belgium.
authors.forename: Laëtitia
authors.initials: L
authors.lastname: Ruppé
authors.affiliation: Laboratory for Functional Morphology, University of Antwerp, 2610 Wilrijk, Belgium Evolutionary Morphology of Vertebrates, University of Ghent, 9000 Ghent, Belgium.
authors.forename: Sam
authors.initials: S
authors.lastname: Van Wassenbergh
authors.affiliation: Laboratory of Functional and Evolutionary Morphology, AFFISH-RC, University of Liège, 4000 Liège 1, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Compère
authors.affiliation: Laboratory of Functional and Evolutionary Morphology, AFFISH-RC, University of Liège, 4000 Liège 1, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Parmentier
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology; D000818:Animals; D001934:Branchial Region / Q000000981:diagnostic imaging / Q000502:physiology*; D005072:Evoked Potentials, Auditory; D005247:Feeding Behavior / Q000502:physiology; D006309:Hearing / Q000502:physiology*; D007568:Jaw / Q000000981:diagnostic imaging / Q000502:physiology*; D053403:Lateral Line System / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D010473:Perciformes / Q000033:anatomy & histology* / Q000502:physiology; D011859:Radiography; D013018:Sound Spectrography; D014741:Video Recording; D014828:Vocalization, Animal / Q000502:physiology*
keywords: Communication; Exaptation; Grunt; Haemulidae; Pharyngeal jaws; Sonic mechanism