A Total-Group Phylogenetic Metatree for Cetacea and the Importance of Fossil Data in Diversification Analyses

Abstract

AbstractPhylogenetic trees provide a powerful framework for testing macroevolutionary hypotheses, but it is becoming increasingly apparent that inferences derived from extant species alone can be highly misleading. Trees incorporating living and extinct taxa are are needed to address fundamental questions about the origins of diversity and disparity but it has proved challenging to generate robust, species–rich phylogenies that include large numbers of fossil taxa. As a result, most studies of diversification dynamics continue to rely on molecular phylogenies. Here, we extend and apply a recently developed meta–analytic approach for synthesizing previously published phylogenetic studies to infer a well–resolved set of species level, time–scaled phylogenetic hypotheses for extinct and extant cetaceans (whales, dolphins and allies). Our trees extend sampling from the ∼ 90 extant species to over 400 living and extinct species, and therefore allow for more robust inference of macroevolutionary dynamics. While the diversification scenarios we recover are broadly concordant with those inferred from molecular phylogenies they differ in critical ways, most notably in the relative contributions of extinction and speciation rate shifts in driving rapid radiations. Supertrees are often viewed as poor substitute for phylogenies inferred directly from character data but the metatree pipeline overcomes many of the past criticisms leveled at these approaches. Meta–analytic phylogenies provide the most immediate route for integrating fossils into macroevolutionary analyses, the results of which range from untrustworthy to nonsensical without them.