Adaptive radiation in electric fish

So it's been a while. I've been meaning to post something, but I'm revising two courses this semester, which is like having to write four blog posts a week. That takes up a lot of my time. Plus I've got several manuscripts in revision, and I'm working on an exciting new student project. Blah, blah, excuses, excuses. I'm busy. So is everyone else.

I did think the paper on adaptive radiation in elephant fish Paramormyrops was extremely interesting. These fish look very similar, but there is a closely-related "species flock" in Africa. Why are there so many species living in such close proximity (as many as 20 species in one location)? It seems they have different signaling methods using their electric organs. Arnegard et al. (the authors of the study) think that sexual selection accounts for the adaptive radiation of these fish, since the electric signaling is used for mate selection. So it's an example of adaptive radiation where the species are not very morphologically diverse. Moral of the story for hardcore structuralists like me: never underestimate the power of function.

Arnegard et al. 2010. Sexual Signal Evolution Outpaces Ecological Divergence during Electric Fish Species Radiation. American Naturalist 176:335–356.

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