The functional morphology of lingual prey capture in a scincid lizard, Tiliqua scincoides (Reptilia: Squamata).

Abstract

We investigated the functional morphology of lingual prey capture in the blue-tongued skink, Tiliqua scincoides, a lingual-feeding lizard nested deep within the family Scincidae, which is presumed to be dominated by jaw-feeding. We used kinematic analysis of high-speed video to characterize jaw and tongue movements during prey capture. Phylogenetically informed principal components analysis of tongue morphology showed that, compared to jaw-feeding scincids and lacertids, T. scincoides and another tongue-feeding scincid, Corucia zebrata, are distinct in ways suggesting an enhanced ability for hydrostatic shape change. Lingual feeding kinematics show substantial quantitative and qualitative variation among T. scincoides individuals. High-speed video analysis showed that T. scincoides uses significant hydrostatic elongation and deformation during protrusion, tongue-prey contact, and retraction. A key feature of lingual prey capture in T. scincoides is extensive hydrostatic deformation to increase the area of tongue-prey contact, presumably to maximize wet adhesion of the prey item. Adhesion is mechanically reinforced during tongue retraction through formation of a distinctive "saddle" in the foretongue that supports the prey item, reducing the risk of prey loss during retraction.