Physalaemus angrensis Weber, Gonzaga & Carvalho-e-Silva, 2006

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 : 50-51

Physalaemus angrensis Weber, Gonzaga & Carvalho-e-Silva, 2006

We found two different calls, referred to as call A and B. Calls A and B are composed of harmonics and a single note each. Call A is composed of pulses whereas Call B has no PAM. Moreover, call B has a stronger general upward FM. Call B can have irregular FM segments and jumps of the fundamental frequency (vs. absent in call A).

Call A ( Fig. 19 A–H and 13F). We examined nine recordings, a total of 32 minutes, with ca. 800 calls from 19 males. Only some of these calls were measured (see Table 2 ). Call duration varies from 0.431 to 0.605 s. In most calls, the limits between the call rise, sustain, and fall are not clear (for example in calls with elliptic envelopes; see below; Fig. 19D ). In calls where the limits are perceptible, the call rise and fall are similar in duration and shape, both have a logarithmic or linear shape, and there is a long sustain, which can have shallow valleys and short slopes (concave and convex shapes, respectively; Fig. 19A ). The amplitude peak is at around the end of the first three fourths of the call duration. The envelope varies from elliptic ( Fig. 19D ) to rectangular ( Fig. 19A ) depending on how emphasized or regular is the sustain. More than 50 % of the energy is concentrated in 37 % of the call duration around the amplitude peak. This call has a strong PAM (there are silence intervals present between pulses; Fig. 19A, B, D, E, G, H ). The rate of the PAM is ca. 58 Hz, yielding ca. 30 pulses throughout the call. Except for the last pulse, the pulse rise is longer than the fall and the amplitude peak is around two thirds of the pulse duration. The last pulse has the opposite envelope with amplitude peak at the beginning ( Fig. 19E ). The first pulses can have much lower amplitude than the others. The last pulse is the longest. There are short silence intervals between pulses, which can be absent between the first and last pulses (pulses are juxtaposed to neighboring pulses; Fig. 19A, B, D, E, G, H ). Intervals are usually eightfold longer than the pulse durations. The call has a harmonic series ( Fig. 13F ). The fundamental frequency is at ca. 410 Hz and this band can be present with low energy or absent in the audiospectrograms. The wave periods are regular and harmonics are clear throughout the call. The dominant frequency varies from ca. 1590 to 1780 Hz ( Fig. 19B ). The dominant harmonic varies from the third to the fifth, but it is usually the fourth. There is no clear shift in the relative energy among the bands throughout the call. Most of the energy is concentrated between 1200 and 1900 Hz (three harmonics). The call has a general upward FM ( Fig. 19B, G ). Additionally, there is PFM throughout the call, which is usually directly proportional to the synchronic pulse-PAM ( Fig. 19E, H ). Calls are usually emitted in short sequences with up to ten calls each ( Fig. 19C, F ).

Call B ( Fig. 19 I–L and 16D). We examined three recordings, a total of 18 minutes, with ca. 150 calls from five males. Only some of these calls were measured (see Table 2 ). Call duration varies from 0.309 to 0.353 s. The call rise and fall are similar in duration and shape (logarithmic-shaped). There is a sustain, which has shallow valleys, usually at its beginning and end ( Fig. 19I, K ). The amplitude peak of the call is at around the end of the first four fifths of the call duration ( Fig. 19I, K ). The envelope varies from elliptic to triangular (pointed left; Fig. 19I, K ). More than 50 % of the energy is concentrated in 32 % of the call duration around the amplitude peak. This call has no PAM. The call has a harmonic series ( Fig. 16D ). The fundamental frequency is ca. 320 Hz and this band can be present with low energy or absent in the audiospectrograms. The wave periods are regular and harmonics are clear throughout the call. The dominant frequency varies from ca. 1080 to 1310 Hz ( Fig. 19J ). The dominant harmonic varies from the second to the seventh harmonic, but it is usually the fourth. There is no clear shift in the relative energy among the bands throughout the call. Most of the energy is concentrated between 900 and 1400 Hz (two harmonics). The call has a general upward FM with short downward FM at the end ( Fig. 19J, L ). The sustain has an up-downward FM ( Fig. 19J, L ). There is clear PFM in some parts of the call. Additionally, several calls have parts with irregular up and downward FM, usually, inversely proportional to the AM directions ( Fig. 19 I–L).

Figures

FIGURE 13. Multiplicity relationship between “instantaneous” dominant frequency and w of calls A of eight Physalaemus species. Each graph shows a single call A of: P. nanus (A), P. spiniger (B), P. crombiei (C), P. signifer (D), P. bokermanni (E), P. angrensis (F), P. atlanticus (G), P. moreirae (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. nanus; A).

FIGURE 16. Multiplicity relationship between “instantaneous” dominant frequency and w of calls B of five Physalaemus species. Each graph shows a single call B of: P. crombiei (A), P. signifer (B), P. bokermanni (C), P. angrensis (D), and P. moreirae (E). 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.

FIGURE 19. Calls A and B of Physalaemus angrensis. Oscillograms (A, C, D, E, I, and K) and audiospectrograms (B, F, G, H, J, and L). A single typical call A (A–B). Four groups of call A (C and F). A variant call A with a different envelope (D and G). Last six pulses of the call A (E and H). A single call B (I–J). A single call B with a different envelope (K–L). Horizontal scale bars have 0.1 s (D, H, K, and L), 20 s (C and F), and 0.05 s (E and H); vertical scale bars have 1 kHz. Filter bandwidth (Hz): FFT (points): 550 (H); 750 (B, F and G); 1024 (J and L).