FIGURE 22 in The use of bioacoustics in anuran taxonomy: theory, terminology, methods and recommendations for best practice

FIGURE 22. Spectrograms and corresponding oscillograms of the advertisement calls of two anuran species, exemplifying the presence of parallel frequency bands in the spectrogram, although at comparatively low FFT resolution (256; Hanning window function), not representing harmonics, but resulting from a high pulse rate. Left: Section of the advertisement call of Elachistocleis sp., with a pulse rate of 245 pulses/second and a total call duration of 2000‒3040 ms. Right: Advertisement call of Physalaemus albonotatus, with seven recognizable and modulated frequency bands. Its call is exceptionally fastly pulsed, with an approximate rate of 470 pulses/second. Figures modified and data taken from Köhler (2000). Spectrograms and oscillograms produced with CoolEdit Pro.