Ecomorphological analysis of aerial performance in a non-specialized lacertid lizard, Holaspis guentheri

Controlled aerial descent has evolved at least 30 times independently in different vertebrate and invertebrate lineages. A whole suite of morphological modifications, such as patagia, lateral skin folds and webbed feet, have been suggested to enhance descending ability. In this study, we compare aerial performance (i.e. vertical and horizontal velocity, horizontal distance covered, duration of descent) and morphology (body mass, body width, inter limb distance, surface area and wing loading) among three species of lizards, representing a range of aerial descenders present within the clade. Our performance measurements show that the lacertid Holaspis guentheri performs intermediately to the specialized gekkonid Ptychozoon kuhli and the rock-dwelling lizard Podarcis muralis. The small relative body mass of H. guentheri results in a low wing loading similar to that of P. kuhli thus enhancing its aerial performance. Whereas the latter generates great lift forces and is able to cover great horizontal distances, H. guentheri's low wing loading seems to be responsible for a slow descent and low impact forces upon landing. Our results show that very small morphological changes may result in noticeable and ecologically relevant changes in performance.