Meeting Abstract

SICB+    Adventures in 3D musculoskeletal modeling methods in the heads of Anolis Lagorio, AD*; Fields, M; Fortner, J; Mackareth, E; Perez, C; McGechie, F; Wilken, A; Leal, M; Ward, CV; Middleton , KM; Holliday , CM; University of Missouri; University of Missouri; University of Missouri; University of Missouri; University of Missouri; University of Chicago; University of Chicago; University of Missouri; University of Missouri; University of Missouri; University of Missouri adlqqd@missouri.edu

Emerging imaging, 3D modeling and quantitative analyses are equipping evolutionary biologists with new approaches to understanding the variation and evolution of the musculoskeletal system. However, challenges and variations with interpreting DiceCT data and higher order use of modeled muscles have not yet been explored by a sample of investigators, and thus the error and accuracy of some digital methods remain unclear. Here we test new approaches to quantifying the shape and function of muscles and bones in the heads of Anolis lizard species. Anolis is a model clade for exploring patterns in functional adaptation, ecomorphology, and evolution of vertebrates. They possess numerous jaw muscles with potentially different anatomies that sculpt the adductor chamber of the skull and impact cranial performance. Here, a quarantined, virtual, academically-diverse graduate class collected 3D musculoskeletal data from two species of Anolis: Anolis sagrei and Anolis pulchellus. We describe comparative approaches employing DiceCT segmentation of jaw muscles, 3D surface attachment mapping and 3D landmarking approaches with the aim of exploring 3D lever mechanics, 3D muscle fiber architecture and sexual dimorphism of the skull. We compare interobserver variation and error in these 3D analyses while also sharing new 3D musculoskeletal data from the Anolis feeding apparatus. These findings demonstrate the accessibility and accuracy of these emerging techniques as well as provide details of the musculoskeletal anatomy of the heads of Anolis ecomorphs important for further study of comparative biomechanics and evolution in the clade.