Physalaemus camacan Pimenta, Cruz & Silvano, 2005

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 : 37

Physalaemus camacan Pimenta, Cruz & Silvano, 2005

We found a single call type for the species, referred to as call A. The call has a single harmonic note with a slight PAM. It is spectrally polymorphic with clear harmonics, sidebands, and deterministic-chaos regime.

Call A ( Fig. 9 A–D and 4E–F). We examined two recordings, a total of five minutes, with ca. 130 calls from two males. Only some of these calls were measured (see Table 2 ). Call duration varies from 0.676 to 0.980 s. The call rise is gradual and longer than the call fall, which is more abrupt. There is a long sustain in the call. Usually the amplitude of the call is regular throughout the call ( Fig. 9A ). However, in some calls, the amplitude increases gradually toward the amplitude peak at the end of the call ( Fig. 9C ). The amplitude peak is at around four fifths of the call duration. Depending on the slope of the sustain and the difference between the amplitude peaks the envelope of the call can vary from rectangular ( Fig. 9A ) to triangular (pointed left; Fig. 9C ). More than 50 % of the call energy is concentrated in 38 % of the call duration around the amplitude peak. The call has a slight PAM (with no silence interval between peaks; Fig. 9A, C ). The rate of the PAM is ca. 13 Hz, forming ca. 10 amplitude peaks throughout the call. The calls can have two different spectral patterns ( Fig. 4E, F ). The bands of one of these patterns ( Fig. 9B ) are multiple of each other and were considered harmonics. The fundamental frequency of this series is ca. 400 Hz ( Fig. 9B ). In the other spectral pattern ( Fig. 9D ), there is a series of bands with fundamental frequency of ca. 100 Hz, which varies continuously and the bands are not integral multiple of each other. The bands of this 100 Hz series seem to be sidebands (i.e., 100 Hz wave as the modulating signal) with the 410 Hz series as the carrier signal ( Fig. 9D ). In most calls, the sidebands are the only bands noticeable. In these calls, the bands are not very clear since there is considerably deterministic chaos ( Fig. 9D ) due to the irregularity of the wave periods of the 100 Hz signal. In the calls where the 400 Hz series are evident, the harmonics are clear due to the higher fundamental frequency and the more regularity (periodicity) of the wave periods. The dominant frequency varies from ca. 1380 to 1660 Hz ( Fig. 9B ). Considering the 400 Hz series, the dominant harmonic varies from the second to the sixth, but it is usually the fourth. There is no clear shift in the relative energy between the bands throughout the call. Most of the call energy is between 1100 and 1800 Hz. This bandwidth corresponds to two harmonics of the 400-Hz series. The frequency bands have a general upward FM throughout the call with a short downward FM at the end ( Fig. 9B ). There is a PFM in the parts of the call where the bands are clear ( Fig. 9B ). This PFM is synchronic and directly proportional to the PAM ( Fig. 9A, B ).

Figures

FIGURE 4. Multiplicity relationship between “instantaneous” dominant frequency and w of calls A of seven Physalaemus species. Each graph shows a single call A of: P. nattereri (A), P. maculiventris (B), P. erythros (C), P. rupestris (D), P. camacan (E; F), P. obtectus (G), P. irroratus (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 w of the measured 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. irroratus; H).

FIGURE 9. Call A of Physalaemus camacan. Oscillograms (A and C) and audiospectrograms (B and D). A single typical call with emphasized harmonics (A and B). A variant call (C and D). A single noisy call with high level of deterministic chaos (C and D). Horizontal scale bars have 0.1 s; vertical scale bars have 1 kHz. Filter bandwidth (Hz): 61.9 (B); 31.0 (D).