Prey transport kinematics in Tupinambis teguixin and Varanus exanthematicus: Conservation of feeding behavior in 'chemosensory-tongued' lizards

Although lizards have been predicted to show extensive intraoral prey-proce ssing behaviors, quantitative analyses of the types of prey-processing beha vior they demonstrate and of their kinematics have been limited. The more b asal lizard lineages (Iguanians) have undergone some study, but the prey-pr ocessing repertoires of crown taxa have not been thoroughly examined and qu antitative comparisons of behaviors within or among species have not been m ade, In this study, the prey transport behavior of the savannah monitor (Va ranus exanthematicus) and gold tegu (Tupinambis teguixin) are described, Al though these two lineages have independently evolved tongues that are highl y specialized for chemoreception, we found that they share the same three d istinct types of transport behavior, These behavior patterns are (i) a pure ly inertial transport, (ii) an inertial transport with use of the tongue, a nd (iii) a non-inertial lingual transport. The tongue is used extensively i n both the inertial and the purely lingual transport behaviors. More than 7 5% of all transport behaviors involved tongue movements. These species appe ar to exhibit a conservation of feeding kinematics compared with patterns k nown for basal lizards. A hypothesis for the evolution of inertial feeding is proposed.