SUMMARY
In most terrestrial tetrapods, the transport of prey through the oral cavity is accomplished by movements of the hyolingual apparatus. Morphological specializations of the tongue in some lizard taxa are thought to be associated with the evolution of vomerolfaction as the main prey detection mode. Moreover, specializations of the tongue are hypothesized to compromise the efficiency of the tongue during transport; thus, driving the evolution of inertial transport. Here we use a large teiid lizard, Tupinambis merianae, as a model system to test the mechanical link between prey size and the use of inertial feeding. We hypothesize that an increase in prey size will lead to the increased recruitment of the cranio-cervical system for prey transport and a reduced involvement of the tongue and the hyolingual apparatus. Discriminant analyses of the kinematics of the cranio-cervical, jaw and hyolingual systems show that the transport of large prey is indeed associated with a greater utilization of the cranio-cervical system (i.e. neck and head positioning). The tongue retains a kinematic pattern characteristic of lingual transport in other lizards but only when processing small prey. Our data provide evidence for an integration of the hyolingual and cranio-cervical systems; thus, providing partial support for an evolutionary scenario whereby the specialization of the tongue for chemoreception has resulted in the evolution of inertial transport strategies.
FOOTNOTES
This work is part of the PhD project of S.M. and is supported by the Legs Prévost (MNHN), ANR 06-BLAN-0132-02 and Phymep Corporation. The authors would like to thank Paul-Antoine Libourel for his help with assembling the data set, and Caroline Simonis for her constructive comments and suggestions on how to analyze the data. We also would like to thank Fettah Kosar and the Harvard CNS facilities for allowing us to CT-scan a specimen of T. merianae. S.M. would like to thank Professor J. Losos for welcoming him at the Losos Lab (Harvard University,Cambridge, MA, USA), during the writing of this manuscript. Finally, the authors would like to thank three anonymous reviewers for their constructive comments on a previous draft of the manuscript.
