KINEMATICS OF FEEDING IN THE LIZARD AGAMA-STELLIO

The kinematics of prey capture, intraoral transport and swallowing in lizards of the species Agama stellio (Agamidae) were investigated usin g cineradiography (50 frames s(-1)) and high-speed video recordings (5 00 frames s(-1)). Small metal markers were inserted into different par ts of the upper and lower jaw and the tongue, Video and cineradiograph ic images were digitized, and displacements of the body, head, upper a nd lower jaw and the tongue were quantified, Twenty additional variabl es depicting displacements and timing of events were calculated, A fac tor analysis performed on the kinematic data separates prey capture an d swallowing cycles from intraoral transport bites, However, the intra oral transport stage cannot be separated into chewing (reduction) and transport bites, The effect of prey type and size on the feeding kinem atics of intraoral transport and swallowing cycles was investigated, D uring the intraoral transport stage, distinct aspects (e.g. durations, maximal excursions) of the gape and tongue cycle are modulated in res ponse to both the size and type of the prey item, The results for A. s tellio generally agree with a previous model, although it is the entir e slow opening phase rather than solely the duration of the second par t of this phase that is affected by the size of the prey, The intraora l transport cycles in A. stellio show the two synapomorphic characteri stics of tetrapods (tongue-based terrestrial intraoral prey transport and the existence of a long preparatory period of prey compression). H owever, not all five characters of the feeding cycle previously propos ed for amniotes are present in A. stellio, One major difference is tha t in A. stellio the recovery of the hyolingual apparatus does not take place during the slow opening phase but during the slow closing/power stroke phase.