Meeting Abstract
The evolution of unique morphologies can change the way an organism interacts with its environment and lead to the exploitation of new niches. However, it is often difficult to study questions about the evolutionary history of such traits because comparative analyses are limited due to the narrow distribution of such traits. In the expansive adaptive radiation of cichlid fishes in East Africa’s rift valley lakes, a rare facial morphology has evolved in at least two lineages, once in Lake Malawi and once in Lake Tanganyika. The trait is characterized by a dramatically hypertrophied snout that folds in on itself to form a flexible flap that rests on the premaxilla, the tooth-bearing upper jaw bone. Flap variation differs between these two lineages. In Lake Malawi, the trait is binary such that only two species within the genus Labeotropheus possess conspicuous flaps. Alternatively, within the Ectodini tribe of Lake Tanganyika the trait appears to vary continuously among its approximately 40 species. While it is speculated that flaps are used during foraging, little is known about how this unique trait might increase evolutionary and/or ecological success within a lineage. To address this question, we analyze the evolutionary history of flap size within the Ectodini along with other functionally salient trophic morphologies, and compare the ecologies of species with and without flaps. Our goal is to elucidate how and why rare traits evolve and how they can impact niche breadth.
