Meeting Abstract

102.4  Saturday, Jan. 7  Evolution and integration of weapons in horned lizards (Phrynosoma) BERGMANN, P.J.*; BERK, C.P.; Clark University; University of Arizona

Many animals posses weapons for defense, prey procurement, and competition for resources. Many of these structures, including horns, antlers, spines, and venom glands exhibit positive allometry, being disproportionately larger and more effective in larger animals. Lizards of the genus Phrynosoma have multiple horns that they use in anti-predator defense. We show that all of these horns are positively allometric, as expected, and study the evolution of horn allometry and the morphological and ontogenetic integration among horns in this clade. The level of integration among horns will shape how horn morphology can evolve. We find that larger and adjacent horns are more integrated with one another morphologically, and in terms of their growth, supportive of both functional and developmental integration hypotheses. We also show that species with outlying horn morphologies also have odd horn allometries, suggesting that the evolution of horn morphology is mediated through the evolution of horn allometry.