KINEMATICS OF FEEDING BEHAVIOUR IN OPLURUS CUVIERI (REPTILIA: IGUANIDAE)

The kinematics of prey capture, reduction and transport to the oesophagus by the iguanian lizard Oplurus cuvieri were investigated using high-speed cinematography (100–200 frames s⁻¹) and cineradiography (60 frames s⁻¹). Thirty feeding sequences from four individuals were analysed. Feeding sequences were divided into four phases: capture, reduction, transport to the oesophagus and cleaning. Quantified kinematic profiles of the head, jaws, hyoid-tongue complex and displacements of the prey to (capture) and within (other phases) the buccal cavity are presented from cinematographic frames. Twenty additional variables, depicting maximal displacements and the timing of events, were calculated from the profiles. Variables documenting gape cycles were used in a first principal component analysis for studying the kinematic relationships between the phases. Markers were placed in the tongue of two individuals for cineradiographic study to illustrate displacements of the tongue. During prey capture, the jaw cycle is divided into slow opening (SO I and SO II), fast opening (FO) and fast closing (FC) stages. During the reduction phase, jaw cycles do not always involve an SO stage and the first reduction cycle never exhibits an SO stage. During transport, the duration of the SO stages is highly variable. During reduction and transport of the prey, the cyclic tongue movements are very similar. Gape opening during cleaning is not divided into two successive stages. We conclude (1) that the capture, reduction and cleaning cycles may be derived from the transport cycle, (2) that the SO stage is determined by tongue displacements in all the phases, (3) that, in the extensive intraoral food processing, related cyclic tongue-jaw displacements are not different, (4) that gape cycles do not always follow the Bramble and Wake model, and (5) that the evolutionary features proposed for Amniota by Reilly and Lauder are present.