Meeting Abstract
The concept of key innovation is among the most unifying ideas in integrative and comparative biology. Key innovations are evolutionary novelties that allow organisms to interact with the environment in a novel way that facilitates expansion into a wide range of niches that were not previously possible. They are thought to be the main intrinsic driver of adaptive radiation, in which a lineage rapidly speciates and diversifies to fill available niches. While key innovations are of broad interest among biologists, the intricacies of how they work is a topic that sits squarely with the functional biologists that make their home in the Society for Integrative & Comparative Biology. In this talk I review one of the most famous examples of key innovation, the specialized pharyngeal jaws of cichlid fishes. In the 1970s, SICB’s Karel Liem initially recognized the derived nature of cichlid pharyngeal jaws and proposed that this novelty is a key to their exceptional diversity because it allows these fish to feed on such a wide diversity of prey items. He later showed that this novelty is shared by three additional fish families and he used this observation to propose monophyly for cichlids, labrids, pomacentrids, and embiotocids in a group named Labroidei. Decades later, phylogenetic analyses of spiny-finned fishes began to carefully test this hypothesis, and through a series of studies the community concluded that the members of Labroidei are in fact not closely related, implying that the derived jaw system evolved independently at least five times. I present new results from a survey of thousands of fish species, that show that fishes with this novelty exhibit rates of body shape evolution that are almost twice that of lineages that lack the novelty, supporting the idea that the novelty spurs ecological diversification.
