TY - JOUR
T1 - The evolution of cranial design and performance in squamates
T2 - Consequences of skull-bone reduction on feeding behavior
AU - Herrel, Anthony
AU - Schaerlaeken, Vicky
AU - Meyers, Jay J.
AU - Metzger, Keith A.
AU - Ross, Callum F.
N1 - Funding Information:
The authors would like to thank Tim Higham and Peter Wainwright for inviting us to present this article at the symposium on the evolution of feeding behavior in vertebrates at the 2007 annual SICB meeting, and SICB for financial support. We would also like to thank animal importers in Belgium (Anaconda Reptiles, Fantasia Reptiles) and the Netherlands (Chameleon trade-house) for donating deceased specimens for morphological analyses. A.H. would like to thank the Journal of Experimental Biology for providing a travel grant which allowed him to attend the 2001 symposium on specialized muscle and subsequently to conduct field work in Australia. Field work in Australia was conducted under permit E24474-1. A.H. is a postdoctoral fellow of the Fund for Scientific Research, Flanders, Belgium (FWO-Vl). Research funded by a PhD grant of the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen) to V.S., a grant of the Belgian American Education Foundation to K.M., and a Journal of Experimental Biology travel grant to J.M.
PY - 2007/7
Y1 - 2007/7
N2 - The evolution of cranial design in lepidosaurians is characterized by a general trend toward the loss of cranial elements. The evolution of relatively lighter skulls in squamates appears tightly coupled to a reduction in relative mass of the jaw adductor, implying functional consequences for bite force and feeding behavior. Interestingly, among squamates the postorbital bar was reduced or lost at least twice independently and taxa characterized by the loss of these cranial elements (e.g., geckos and varanids) are generally reported as having a mobile skull. In Gekkotans, the loss of the postorbital bar was accompanied by a reduction of the supratemporal bar, resulting in a pronounced cranial kinesis. Our data show that having a kinetic skull has functional consequences and results in a reduction in bite force. The lower bite force may in turn be responsible for the decreased feeding efficiency as reflected in the longer duration of intra-oral transport cycles. Gekkotans, however, appear to exploit their intracranial mobility in ways that increases the velocity of jaw movement during opening and closing, which may allow them to capture more elusive prey. The morphological changes observed in the evolution of the cranial system in squamates appear tightly linked to functional and constructional demands on the skull, making squamate skull evolution a model system to investigate the consequences of morphological changes in a complex integrated system of performance, behavior, and ecology.
AB - The evolution of cranial design in lepidosaurians is characterized by a general trend toward the loss of cranial elements. The evolution of relatively lighter skulls in squamates appears tightly coupled to a reduction in relative mass of the jaw adductor, implying functional consequences for bite force and feeding behavior. Interestingly, among squamates the postorbital bar was reduced or lost at least twice independently and taxa characterized by the loss of these cranial elements (e.g., geckos and varanids) are generally reported as having a mobile skull. In Gekkotans, the loss of the postorbital bar was accompanied by a reduction of the supratemporal bar, resulting in a pronounced cranial kinesis. Our data show that having a kinetic skull has functional consequences and results in a reduction in bite force. The lower bite force may in turn be responsible for the decreased feeding efficiency as reflected in the longer duration of intra-oral transport cycles. Gekkotans, however, appear to exploit their intracranial mobility in ways that increases the velocity of jaw movement during opening and closing, which may allow them to capture more elusive prey. The morphological changes observed in the evolution of the cranial system in squamates appear tightly linked to functional and constructional demands on the skull, making squamate skull evolution a model system to investigate the consequences of morphological changes in a complex integrated system of performance, behavior, and ecology.
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U2 - 10.1093/icb/icm014
DO - 10.1093/icb/icm014
M3 - Article
C2 - 21672824
AN - SCOPUS:38749154771
SN - 1540-7063
VL - 47
SP - 107
EP - 117
JO - Integrative and Comparative Biology
JF - Integrative and Comparative Biology
IS - 1
ER -