The morphological basis of weight-bearing in the scansors of the tokay gecko (Reptilia: Sauria)

Abstract

The scansors (subdigital, lamellar, scalelike structures) of gekkonid lizards bear adhesive setae and during locomotion on smooth surfaces must bear the weight of the animal. Thus, the body weight is supported by the integument and relatively large tensile stresses are imposed upon the skin at these times. In order that the relatively delicate integument is not damaged or stripped away from underlying tissues, precise linkages at transition zones occur. The setae themselves consist of material of high tensile strength, the epidermal–dermal junction is an extremely tight bond and the stratum compactum of the dermis provides a direct connection between the epidermis and the lateral digital tendon complex. The latter, in turn, connects directly to the skeleton by way of the metacarpo- or metatarso-phalangeal joint capsules. Additionally, elastin fibrils in the dermis and the collagen fibrils of the dermis and lateral digital tendon network are aligned in parallel with the long axis of each digit and are arranged to permit controlled distortion of the exposed scansorial surfaces.