Title
The functional significance of the lower temporal bar in **Sphenodon punctatus** The functional significance of the lower temporal bar in **Sphenodon punctatus**
Author
Faculty/Department
Faculty of Sciences. Biology
Publication type
article
Publication
London ,
Subject
Biology
Source (journal)
The journal of experimental biology. - London
Volume/pages
211(2008) , p. 3908-3914
ISSN
0022-0949
ISI
000261260500019
Carrier
E
Target language
English (eng)
Full text (Publishers DOI)
Affiliation
University of Antwerp
Abstract
One of the major conundrums in the evolution of vertebrate cranial design is the early loss and frequent redevelopment of the lower temporal bar in diapsids. Whereas it has been proposed that the reduction of the lower temporal bar allows for an increase in jaw adductor mass and bite force, this has never been tested experimentally. As the sole recent representative of the Rhynchocephalia, Sphenodon punctatus is different from other extant lepidosaurians in having a fully diapsid skull and in using translation to shear food rather than using the typical puncture-crushing of other lizards. In the present study, we show that S. punctatus has lower bite forces compared with extant lepidosaurians. Moreover, dissection of the jaw muscles of an adult S. punctatus shows that the mass of the external jaw adductor muscle is significantly smaller than that of lizards, probably accounting for the lower measured bite forces. An analysis of the transport cycles suggests a less efficient prey transport in S. punctatus compared with an agamid lizard of similar size in terms of handling time and number of cycles needed to crush similar prey. Modelling of biting in S. punctatus suggests a different role of the jaw adductor muscles during biting and a clear functional role for the lower temporal bar. Future finite element models may provide better insights into the function of the lower temporal bar in S. punctatus.
E-info
https://repository.uantwerpen.be/docman/iruaauth/cdc240/cd53264.pdf
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