Physalaemus aguirrei Bokermann, 1966

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 : 68

Physalaemus aguirrei Bokermann, 1966

We found a single call type for the species, referred to as call A. The call is composed of a single harmonic note with an elliptic or trapezium-like envelope. It has a general downward FM, with an up-downward FM segment in the first third of the call.

Call A ( Fig. 37 A–D and 33E). We examined seven recordings, a total of 11 minutes, with ca. 400 calls from 10 males. Only some of these calls were measured (see Table 2 ). Call duration varies from 0.179 to 0.237 s. Usually, call rise and fall are similar in duration and shape. The call rise is usually composed of two consecutive exponential- or linear-shaped segments, whereas the call fall has an exponential or logarithmic shape ( Fig. 37A ). The sustain can be irregular with short and shallow valleys, composed of a single deep valley (concave shape), or regular without internal AM segments ( Fig. 37A, C ). In some calls, the rise is much longer than fall and it remains with very low amplitude until the limit with the sustain, where the amplitude increases abruptly. The amplitude peak is around the middle of the call duration. The envelope varies from elliptic ( Fig. 37C ) to slightly rectangular (in calls in which the rise is not gradual; Fig. 37A ). More than 50 % of the call energy is concentrated in 34 % of the call duration around the amplitude peak. There is no PAM in the call. The call has a harmonic series ( Fig. 33E ). The fundamental frequency is ca. 640 Hz and approximately the first eight harmonics are emphasized. The wave periods are regular and harmonics are clear throughout the call. The dominant frequency varies from ca. 770 to 3380 Hz ( Fig. 37B ). The dominant harmonic varies from the first to the sixth (except the second and third). There is a clear shift in relative energy between the bands; the dominant frequency gets higher until three fourths of the call duration, starting at the first harmonic, moving to the fourth and fifth, and ending at the sixth ( Fig. 33E ). Most of the call energy is between 700 and 3950 Hz (five to six harmonics). The call has a general downward FM ( Fig. 37B, D ). Additionally, the calls have an up-downward FM in the first third of the call duration, yielding arc-shaped bands in this part of the call ( Fig. 37B ), and a short downward FM at the end ( Fig. 37B, D ). The general downward FM and the initial up-downward FM result in S-shaped harmonics when considering the entire call. There is no PFM.

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 37. Call A of Physalaemus aguirrei. Oscillograms (A and C) and audiospectrograms (B and D). A typical call A (A–B). A variant call A with a different envelope and initial FM segment (C–D). Horizontal scale bars have 0.1 s; vertical scale bars have 1 kHz. FFT (points): 1500 (B); 1024 (D).