Structural characteristics of the patagium of Ptychozoon kuhli (Reptilia: Gekkonidae) in relation to parachuting locomotion

Ptychozoon kuhli is known for its parachuting/gliding capabilities. In this contribution, we document the allometric scaling properties of its patagium, accessory flaps and folds, and its total body surface area and compare them to similar attributes of the agamine lizard Draco volans. Ptychozoon kuhli has passive patagia that lack skeletal support and muscular control. Patagial area in P. kuhli is smaller than that in D. volans for individuals of identical snout-vent length, but the accessory folds and flaps compensate for this shortfall and overall P. kuhli has equivalent total body surface area to D. volans for equally sized individuals. The structure of the patagium of Ptychozoon kuhli was investigated in terms of its scalation patterns and structural integrity, its relationship to the body wall and its mechanism of erection, and the distribution of mechanoreceptive sensilla across its surface. Scalation patterns and the internal architecture of the patagium indicate how its shape and form are maintained as it erects and becomes exposed to air flow. Its cross-sectional shape, together with that of the entire body indicates how it is able to behave as an airfoil. The distribution of sensilla across the patagial surface reflect positioning indicative of the monitoring of scale-to-scale contact on the dorsal surface, and possibly air pressure and flow on the ventral surface.