Meeting Abstract

22.5  Sunday, Jan. 4  Does Morphological Integration Have Macroevolutionary Implications? HABER, Annat; University of Chicago annat@uchicago.edu

The study of morphological integration has received increasing attention in evolutionary biology in the last two decades. Based on previous theoretical and empirical work, an association is expected between ontogenetic integration within a species and that species potential to evolve and diversify. However, both positive and negative relationships have been suggested, and there is as yet little empirical data to support either hypothesis. The goal of my project is to test these hypotheses using the ruminant skull as a model system. Extant ruminant lineages differ greatly in their level and pattern of both diversification and morphological integration, providing a broad comparative basis for studying that relationship from a macroevolutionary point of view. In this talk I will present results from a preliminary database, covering 28 species including representatives of all ruminant subfamilies. 3D landmark configurations were collected from the skulls using Microscribe MXL. Integration was calculated based on inter-landmark distances. Taxonomic diversification was calculated as log-scale rates. Phylogenetic structure was tested and incorporated both globally (using a distance matrix) and locally (using a clade membership matrix) in order to test for a phylogenetic effect at each node. Integration level shows little phylogenetic effect throughout the ruminant clade, but a significant phylogenetic effect was detected at the origin of Caprinae and Capreolinae. In addition, the results suggest a negative relationship between integration and diversification at the species and genus level but positive one at the subfamily level.