Biomechanical Assessment of Evolutionary Changes in the Lepidosaurian Skull
Biomechanical assessment of evolutionary changes in the lepidosaurian skull Mehran Moazena,1, Neil Curtisa, Paul O’Higginsb, Susan E. Evansc, and Michael J. Fagana aDepartment of Engineering, University of Hull, Hull HU6 7RX, United Kingdom; bThe Hull York Medical School, University of York, York YO10 5DD, United Kingdom; and cResearch Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom Edited by R. McNeill Alexander, University of Leeds, Leeds, United Kingdom, and accepted by the Editorial Board March 24, 2009 (received for review December 23, 2008) The lepidosaurian skull has long been of interest to functional mor- a synovial joint with the pterygoid, the base resting in a pit (fossa phologists and evolutionary biologists. Patterns of bone loss and columellae) on the dorsolateral pterygoid surface. Thus, the gain, particularly in relation to bars and fenestrae, have led to a question at issue in relation to the lepidosaurian lower temporal variety of hypotheses concerning skull use and kinesis. Of these, one bar is not the functional advantage of its loss (13), but rather of of the most enduring relates to the absence of the lower temporal bar its gain in some rhynchocephalians and, very rarely, in lizards in squamates and the acquisition of streptostyly. We performed a (12, 14). This, in turn, raises questions as to the selective series of computer modeling studies on the skull of Uromastyx advantages of the different lepidosaurian skull morphologies. hardwickii, an akinetic herbivorous lizard. Multibody dynamic anal- Morphological changes in the lepidosaurian skull have been ysis (MDA) was conducted to predict the forces acting on the skull, the subject of theoretical and experimental studies (6, 8, 9, and the results were transferred to a finite element analysis (FEA) to 15–19) that aimed to understand the underlying selective crite- estimate the pattern of stress distribution.
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