Meeting Abstract

58.1  Saturday, Jan. 5  Where should we expect to find Early bursts of trait evolution? A case study using Carnivora. SLATER, GJ*; FRISCIA, AR; Smithsonian Institute; Univ. of California, Los Angeles gslater@ucla.edu

George Gaylord Simpson famously postulated that higher taxa originated as adaptive radiations – early bursts of lineage and phenotypic evolution that slowed through time as niches became saturated. Simpson was a paleontologist, and his ideas were based, in large part, on his reading of the mammalian fossil record. Yet recently developed phylogenetic methods have failed to find broad support for early burst type models in phenotypic datasets of extant taxa. Here, we assemble a comparative ecomorphological dataset for extant Carnivora and use a series of phylogenetic comparative methods to investigate tempo and mode of phenotypic evolution. We find strong support for an early burst of evolution in the dominant axis of ecomorphological evolution in carnivores, with different models supported for other axes. Significantly, an early burst is not supported for body size data, even though body size is often held to correlate with ecology. Simpson’s observations, which were based largely on ecomorphological traits, appear to hold for carnivores. The pervasive use in comparative methods of body size data as a surrogate for species’ ecology may obscure the underlying mode of evolution of higher taxa.