Structure of the larynx of the tokay gecko (Gekko gecko), with particular reference to the vocal cords and glottal lips

Abstract

The ability to vocalize is well-known in gekkonid lizards but relatively little attention has been paid to the structure of the vocal apparatus. In this study we briefly review the structure of the larynx and associated musculature of the tokay gecko as a baseline for a comparative survey of the family. The cricoid and arytenoid cartilages form the skeleton of the larynx and are controlled by constrictor and dilator muscles. The gross morphology of the vocal cords and glottal lips is then described, the structure being elucidated by way of dissection, histology, and scanning electron microscopy. The vocal cords run between the arytenoid and cricoid cartilages, are highly elastic, and bear a highly folded mucosa. The lips of the glottis have a structure reminiscent of erectile tissue. The respiratory mucosa of the larynx varies according to position and may be related to the tonal aspects of sound production. The structure of the larynx is compared with that of other vertebrates, and the relationship between morphology and phonation is considered.