Meeting Abstract

8.4  Monday, Jan. 4  Comparative Analysis of Axial Musculature in Snakes GARTNER, Gabriel E*; JAYNE, Bruce C; GARLAND JR., Ted; University of California, Riverside; University of Cincinnati; University of California, Riverside ggart001@ucr.edu

Locomotion is a critical selective factor in shaping both the morphology and physiology of animals. Although snakes share a limbless body plan, they have considerable diversity in their types of locomotion, habitat use and axial musculoskeletal morphology. Despite recent advances in higher-level snake phylogenies, no previous study has used modern quantitative phylogenetic methods to analyze this diversity. Here, we use phylogenetic multiple regression to analyze patterns of interspecific diversity in the spinalis muscle of snakes using a data set of 133 species in 13 taxon groups (monophyletic groups on our tree, often representing more than one family) from both the literature and original data. A phylogenetic tree was constructed from the literature, and data on relative length of the spinalis muscle were analyzed using both conventional and phylogenetic statistics. Non-nested models incorporating either log10-transformed numbers of body vertebrae, habitat type, and “clade”—and various combinations therein—were used to examine their effects on several dependent variables associated with the spinalis muscle. Initial results indicate that the single best predictive model is non-phylogenetic (i.e., assumes a “star” phylogeny) and includes habitat and clade as predictor variables, thus indicating an effect of habitat (or ecology) and that phylogenetic signal, the tendency for related species to resemble one another, is present at the level of differences among major clades of snakes.