Modulatory complexity of the feeding repertoire in scincid lizards

The kinematics of jaws and tongue, and jaw muscle activity patterns were in vestigated in the omnivorous lizard Tiliqua rugosa, and the herbivorous Cor ucia zebrata (Scincidae) during feeding. Small metal markers were inserted into different parts of the skull, the jaws, and the tongue. Video and cine radiographic images were digitized and displacements of the head, jaws, and tongue were quantified. Additionally, muscle activity patterns were record ed, digitized and several variables were determined quantitatively. The eff ect of food type on the jaw and hyolingual movement patterns and the jaw mu scle activity patterns was investigated for both species. The kinematic dat a indicate that distinct aspects of gape and tongue cycles are modulated in response to the food characteristics. Similarly, in both species, muscle a ctivity patterns are altered in response to the type of food eaten. A compa rison of kinematic and electromyographic patterns during intraoral transpor t cycles for both species shows that these can be related to food character istics such as toughness and mobility. Differences between both species in the response to changes in food characteristics are minor. Clearly both spe cies are able to fine tune the activation of the jaw muscles, resulting in the appropriate movement patterns for the type of food eaten.