It is well documented that coordination of feeding behavior in anuran amphibians requires precise coordination of the jaw levators and depressors with the timing of the protraction of the tongue. (for review, see Nishikawa, 2000). However, the neuronal mechanism initiating and synchronizing this coordination is not well understood. In addition to the intermandibularis muscle and tongue musculature in the lower jaw, there is a small, transverse muscle at the tip of the jaw, the m. submentalis. Previous anatomical work has demonstrated the presence of muscle spindles in the submentalis, leading to the hypothesis that the activation of this muscle may provide proprioceptive information to aid in coordinating the feeding biomechanics in Rhinella marina. Here, we demonstrate that the submentalis likely acts as a ‘trigger’ to initiate the hypoglossal nerve to activate the tongue, and without feedback information from the muscle spindles of the submentalis, tongue protraction is compromised.
Feeding biomechanics of Late Triassic metoposaurids (Amphibia: Temnospondyli): a 3D finite element analysis approach
