DISSERTATION RESEARCH: Testing macroevolutionary predictions of diversity and disparity in the ray-finned fishes

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Understanding why some groups of organisms have more species than other groups of organisms is a long-standing goal in evolutionary biology. One proposed explanation for the process that creates this uneven diversity is evolvability, the idea that some lineages that have the intrinsic ability to evolve novel morphologies also have an increased ability to generate new species. Ray-finned fishes, representing half of all vertebrate diversity with 30,000 species, have an astonishingly disparate array of body forms. Fishes are also intensively harvested for human consumption, potentially leading to major impacts on their diversity and their ability to serve both as ecological role players and as a human food source. This project will aim to test the evolvability hypothesis by collecting data on fish body shape using museum collections and crowdsourcing. The researchers will digitize a vast store of biodiversity in museum collections to be made available online, for use by the public and interested researchers. This project will (1) build the largest phylogeny of vertebrates, with over 12,000 species represented, (2) digitize ichthyology collections at three museums, (3) collect the largest geometric morphometric dataset, consisting of shape data for over 9,000 species of fishes, and (4) reconstruct the disparity among different fish lineages, and how their rates of body shape evolution have changed over time. Several key macroevolutionary predictions can be made based on differential evolvability across clades. More evolvable lineages should have higher richness and diversification rates, and enjoy more phenotypic disparity and rates of phenotypic evolution. Additionally, lineages that enjoy fast phenotypic evolution should also diversify into a larger variety of ecological niches.