RUI: Collaborative Research: The Origin and Diversification of Hearing in Malagasy-South Asian Cichlids

American Museum Natural History, New York NY

Investigators

Abstract

This project comprises a series of interdisciplinary studies of the functional evolution of hearing in cichlid fishes. Cichlids are freshwater fishes that often serve as model organisms for evolutionary and behavioral studies. Although it is not widely known, the Malagasy and South Asian (but not the African or Neotropical) cichlids exhibit modifications of the ear, skull and gas bladder, which create a direct mechanical linkage between the gas bladder and inner ear. Similar structures in other fishes are known to bestow enhanced hearing ability. A high degree of variability of these structures in cichlids suggests that hearing abilities have evolved and diversified within this group of fishes, and provides us a uniquely powerful model system to explore the origin of a new sensory ability and the subsequent evolutionary diversification of a new sense. This collaborative project combines comparative morphological studies of accessory hearing structures with experimental studies of hearing ability using neurophysiological techniques. Field and laboratory studies will document the diversity of hearing ability and correlate differences in perceptual ability with anatomical and ecological features. Malagasy-South Asian cichlids present an ideal case to test the hypothesis that new sensory systems evolve in low-noise habitats to exploit new sensory opportunities, rather than evolving in high-noise habitats to conserve function in the face of increased noise.