@article{26f961f7cd0248c4a6a757858ecb9db2,
title = "The evolution of bite force in horned lizards: the influence of dietary specialization",
abstract = "Dietary specialization is an important driver of the morphology and performance of the feeding system in many organisms, yet the evolution of phenotypic specialization has only rarely been examined within a species complex. Horned lizards are considered primarily myrmecophagous (ant eating), but variation in diet among the 17 species of horned lizards (Phrynosoma) makes them an ideal group to examine the relationship between dietary specialization and the resultant morphological and functional changes of the feeding system. In this study, we perform a detailed analysis of the jaw adductor musculature and use a biomechanical model validated with in vivo bite force data to examine the evolution of bite force in Phrynosoma. Our model simulations demonstrate that bite force varies predictably with respect to the gape angle and bite position along the tooth row, with maximal bite forces being attained at lower gape angles and at the posterior tooth positions. Maximal bite forces vary considerably among horned lizards, with highly myrmecophagous species exhibiting very low bite forces. In contrast, members of the short-horned lizard clade are able to bite considerably harder than even closely related dietary generalists. This group appears to be built for performing crushing bites and may represent a divergent morphology adapted for eating hard prey items. The evolutionary loss of processing morphology (teeth, jaw and muscle reduction) and bite force in ant specialists may be a response to the lack of prey processing rather than a functional adaptation per se.",
keywords = "biomechanical model, bite force, diet, jaw muscle, lizard",
author = "Meyers, {Jay J.} and Nishikawa, {Kiisa C.} and Anthony Herrel",
note = "Funding Information: The authors would like to thank the following curators and museum staff for allowing them to measure specimens in their care: George Bradley (University of Arizona), Dave Wake and Javier Rodriquez (University of California Berkeley Museum of Vertebrate Zoology), Brad Hollingsworth (San Diego Natural History Museum), Alan Resetar (Chicago Field Museum of Natural History), Kent Beaman (Los Angeles County Natural History Museum), Jonathan Campbell (University of Texas at Arlington), Tad Theimer (Museum of Vertebrates at Northern Arizona University), Robert Drewes and Jens Vindum (California Academy of Sciences). The authors would also like to thank Peter Aerts who developed the static bite force model, Bieke Vanhooydonck who helped with the phylogenetic analysis, and two anonymous reviewers for helpful and constructive comments on an earlier version of the manuscript. J. Meyers was funded by NIH MSD Grant # R25 GM 056931-07 and a J. Exp. Biology travel grant. Funding Information: The authors would like to thank the following curators and museum staff for allowing them to measure specimens in their care: George Bradley (University of Arizona), Dave Wake and Javier Rodriquez (University of California Berkeley Museum of Vertebrate Zoology), Brad Hollingsworth (San Diego Natural History Museum), Alan Resetar (Chicago Field Museum of Natural History), Kent Bea-man (Los Angeles County Natural History Museum), Jonathan Campbell (University of Texas at Arlington), Tad Theimer (Museum of Vertebrates at Northern Arizona University), Robert Drewes and Jens Vindum (California Academy of Sciences). The authors would also like to thank Peter Aerts who developed the static bite force model, Bieke Vanhooydonck who helped with the phylogenetic analysis, and two anonymous reviewers for helpful and constructive comments on an earlier version of the manuscript. J. Meyers was funded by NIH MSD Grant # R25 GM 056931-07 and a J. Exp. Biology travel grant. Publisher Copyright: {\textcopyright} 2017 Anatomical Society",
year = "2018",
month = feb,
doi = "10.1111/joa.12746",
language = "English (US)",
volume = "232",
pages = "214--226",
journal = "Journal of Anatomy",
issn = "0021-8782",
publisher = "Wiley-Blackwell",
number = "2",
}