Ecological Factors and Jaw Morphology in Lepidosauria: A Geometric Morphometric and Biomechanical Approach

Abstract

Lepidosauria consists of two reptilian orders, with squamates, the larger of the orders, consisting of about 11,000 species and are widespread globally. As a group, lepidosaurs are very diverse in habitat, leg development, dietary behavior, and overall morphology. This study aims to reveal whether ecological inferences can be made on extant squamate taxa based on their jaw morphology as was the case for mammal jaws and squamate skulls and to determine if we can test the rate of change in mandible shape over time. To achieve these objectives, this study employs landmark-based geometric morphometrics and evaluation of biomechanical markers to elucidate relationships between squamate jaw morphology and ecological niches. This study establishes connections between limb development and anterior mechanical advantage, posterior mechanical advantage, and overall jaw shape. Connections between jaw shape evolution and limb development and habitat are also noted here. Further, anterior mechanical advantage can distinguish carnivorous and omnivorous taxa as well as fossorial and terrestrial taxa.