Physalaemus maximus Feio, Pombal & Caramaschi, 1999

Hepp, Fábio & Pombal, José P., 2020, Review of bioacoustical traits in the genus Physalaemus Fitzinger, 1826 (Anura: Leptodactylidae: Leiuperinae), Zootaxa 4725 (1), pp. 1-106 : 71

Physalaemus maximus Feio, Pombal & Caramaschi, 1999

We found a single call type for the species, referred to as call A. The call is composed of a single harmonic note with a subtle PAM, with no silence intervals. It has a long duration and a very low fundamental frequency with subtle PFM throughout the call. The bands have a slight general upward FM and a downward FM at the end, yielding a slight arc shape in the audiospectrogram when considering the entire call.

Call A ( Fig. 39 A–D and 33G). We examined seven recordings, a total of five minutes, with ca. 90 calls from 11 males. Only some of these calls were measured (see Table 2 ). Call duration varies from 1.887 to 2.446 s. The call rise is longer than call fall or both are similar in duration. Call rise and fall have exponential, linear or logarithmic shape. There is a long sustain. It is usually almost flat but slightly irregular ( Fig. 39A ). However, in some calls, the beginning of this segment has low amplitude, which gradually increases towards the end of the call ( Fig 39C ). The amplitude peak is usually at the end of the first two thirds the call duration. The amplitude of the call is usually at three fifths of the call duration. The envelope varies from elliptic, rectangular ( Fig. 39A ) to triangular (pointed left; Fig. 39C ) depending on the steepness of the sustain and position of the amplitude peak of the call. More than 50 % of the call energy is concentrated in 36 % of the call duration around the amplitude peak. The call can have a slight PAM (silence intervals absent between peaks). The rate of the PAM is ca. 10 Hz, forming ca. 22 amplitude peaks throughout the call. The call has a harmonic series ( Fig. 33G ). The fundamental frequency is ca. 170 Hz. This band and the next harmonic are absent in audiospectrograms. There are usually ca. seven emphasized harmonics. The wave periods are regular and harmonics are clear throughout the call. The dominant frequency varies from ca. 1000 to 1030 Hz ( Fig. 39B ). The dominant harmonic varies from the third to the ninth, but it is usually the sixth ( Fig. 33G ). There is no clear shift in the relative energy between the bands throughout the call. Most of the call energy is between 850 and 1550 Hz (five harmonics). The call has a general FM slightly upward and a short downward FM at the end, yielding a slight arc shape in the audiospectrogram when considering the entire call ( Fig. 39B, D ). Additionally, there can be a slight PFM throughout the call, which is usually independent of PAM or can be directly proportional and synchronic to some parts of the PAM.

Figures

FIGURE 33. Multiplicity relationship between “instantaneous” dominant frequency and w of calls A of eight Physalaemus species. Each graph shows a single call A of P. cuvieri (A), P. ephippifer (B), P. fischeri (C), P. cicada (D), P. aguirrei (E), P. soaresi (F), P. maximus (G), P. feioi (H). Grid corresponds to the harmonic values (right y-axis). Red squares are the values of “instantaneous” dominant frequency; blue circles are the values of the reciprocal of w; green triangles are the factor values of the ratio “instantaneous” dominant frequency / w reciprocal per delta time. Delta time corresponds to the duration of one period of the measured acoustic oscillation. Note that factors around integer values suggest harmonic relationship between the frequency calculated (w reciprocal) and the dominant frequency. Factors multiple of ½ of the fundamental frequency correspond to subharmonics (see P. ephippifer; B).

FIGURE 39. Call A of Physalaemus maximus. Oscillograms (A and C) and audiospectrograms (B and D). A typical call (A–B). A variant call with different envelope and less frequency-modulated (C–D). Horizontal scale bars have 0.5 s; vertical scale bars have 1 kHz. Filter bandwidth (Hz): 30.7 (B); 38.4 (D).