Evolution of cleaner fishes
Cleaning symbioses are complex, mutualistic interactions between a cleaner that eats the ectoparasites off a client. In fishes there are fewer than 300 cleaner species making it an extremely unusual and rare feeding strategy. Here we investigated the feeding morphology of cleaner gobies, tiny coral reef fishes, and found a correlation between ecology and morphology and their respective degrees of specialization.
Body shape of rheophilic pacus
Pacus are the herbivorous cousins of piranhas that eat nearly anything. However, a few phytophagous species feed almost exclusively on a riverweed, a plant that is restricted to river rapids, while other pacus hardly touch it. Coincidentally, the species that feed on riverweed also live in the river rapids full time. Here, we found that body shape and overcoming the challenges of high flow environments have a lot to do with feeding on riverweed.
Jaw biomechanics of scale-feeding fishes
Lepidophages are fishes that specialize in feeding on the scales and mucous of other fishes. While, it is primarily a juvenile feeding behavior, there are a few species that continue to scale-feed throughout adulthood. Here we examined the ontogenetic changes in jaw biomechanics of two adult scale-feeders and their closest non-scale-feeding relatives. We found few shared traits between scale-feeders other than that they both retain their specialized juvenile teeth.