Fig. 6. Discriminant function analysis (DFA) of EOD, chirp and GFR parameters. Scatter plots of first versus second (A) and first versus third (B) canonical roots from a DFA based on all signal parameters reveal the ability of these roots to segregate apteronotid species. Each data point represents a single fish, and species are color-coded as indicated. Some species (e.g. P. hasemani and A. leptorhynchus in A, and `A.' bonapartii and P. gimbeli in B) were well-segregated. Other species (e.g. S. terminalis and S. cf. roseni) overlapped considerably. (C) Performance of DFAs based on all signal parameters, EOD parameters only, chirp parameters only, or GFR parameters only in correctly classifying the species of individuals in leave-one-of-each-species-out cross-validations (see Materials and methods). The broken black line represents performance predicted based on chance alone. All DFAs correctly classified individuals at rates exceeding chance, but DFAs based on EODs and chirps performed better than those based on GFRs.