Fig. 4: Scatterplots of the first two principal components (PC1 and PC2) based on various acoustic features in Holocentridae across different taxonomic levels.

All scatterplots were performed with six acoustical variables (sound duration, number of pulses, fundamental and dominant frequencies, pulse period, and duration of the last pulse) of the sounds produced by (a) the different genera of Holocentrinae (N = 189), b Myripristis species of group 1 (N = 61), c Sargocentron species (N = 101), d Neoniphon species (N = 77).