Males of Physalaemus pustulosus are capable of producing two sounds simultaneously. All other known cases of complex frog calls are instances of the different sounds being produced serially. Comparison of call analyses and laryngeal morphology among Physalaemus gracilis, P. olfersi and P. pustulosus leads to the conclusion that the two sounds are produced by separate vibrating structures in the larynx. Lateral passageways bypassing the median free edges of the vocal cords in all three of these species are described, a feature not previously reported for any anuran larynx. A mechanism is suggested that integrates the available knowledge into a hypothesis of call production in P. pustulosus.
No takes yet. Share an insight, caveat, or question.
Drewry et al. (1982) studied this question.