This project will investigate the factors that have influenced the evolution of the spectacular diversity of fish body shapes, which range from globular pufferfishes to thin elongated spaghetti eels. Experimental studies and mechanical models have revealed how certain body shapes maximize swimming and feeding ability of the fish, in response to ecological factors such as predator presence or habitat and food availability, or in response to environment conditions such as water temperature and salinity. However, very little is known about how these ecological and environmental factors interact to explain fish body shape over evolutionary time-scales. This research will test hypotheses of the ecological, environmental and functional drivers of body form evolution across teleost fishes using a dataset of body shape diversity that will be generated from approximately 7,500 fish species. The project also will help to digitize the fish collections of several natural history museums making the information collected freely available to the public. Approximately 40 undergraduate students will receive training in fundamental research skills and will work together to design and execute an ambitious group research project based on the data they help to collect. Beyond illuminating the mechanisms by which life diversifies, in particular the process of convergent evolution whereby independent fish lineages have evolved similar body shapes, this study will provide the basis for identifying functional groups of fish, which are used for assessing aquatic ecosystem health.
This research will use a phylogenetic comparative approach to reconstruct the history of ecological shifts and biological innovations and their impact on trends in teleost shape diversity. Body-shape, including regions vital for swimming and prey-capture performance, will be estimated from approximately 20,000 teleost specimens using geometric morphometrics and linear measurements on lateral and dorsal views. The teleost ecomorphospace generated will provide the context for exploring the nature of exceptional adaptive radiations, such as the African rift lake cichlids. Large databases of biological, environmental and ecological and functional traits will be assembled from the scientific literature and museum records. Morphological convergence, novelty, and the ecological, environmental and functional factors associated with them, will be identified using an adaptive landscape approach using Ornstein-Uhlenbeck models in a robust phylogenetic framework. The project will test predictions based on biomechanical and physiological models as well as experimental evidence that the most streamlined shapes will evolve in teleosts that rely more on ram feeding and body-caudal propulsion, feed on small elusive prey, or live in environments that are less complex, have high flow, low salinity, or high dissolved oxygen contents.
