Physalaemus rupestris Caramaschi, Carcerelli & Feio, 1991

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 : 35

Physalaemus rupestris Caramaschi, Carcerelli & Feio, 1991

We found two different calls, referred to as call A and B. Call B differs from call A by its longer duration and pulse- PAM with irregular silence intervals. Additionally, the envelope of call A is elliptic or triangular whereas that of call B is triangular or rectangular.

Call A ( Fig. 8 A–D and 4D). We examined three recordings, a total of one minute, with 18 calls from one male. All these calls were measured (see Table 2 ). Call duration ranges from 0.057 to 0.149 s. The call rise is similar in duration or shorter than the fall; the call fall is gradual, whereas the call rise has an exponential shape. The amplitude peak is usually at around the end of the first sixth of the call duration. The envelope of the call varies from elliptic to triangular (pointed right; Fig. 8A, C, D ). More than 50 % of the call energy is concentrated in 28 % of the call duration around the amplitude peak. Some calls have a strong PAM (with silence intervals present between pulses; Fig. 8D ). In those calls the rate of this PAM is ca. 15 Hz, always forming two pulses. The envelope of these pulses is usually elliptic with the amplitude peak at the middle of the pulse. The last pulse is usually ca. 1.5 times longer than the first ( Fig. 8C ). The call is composed of harmonics ( Fig. 4D ). The harmonics are very close to each other and not very clear due to the low fundamental frequency and the lack of the wave periodicity throughout the call. The fundamental frequency is approximately 225 Hz and this band can be present with low energy or absent in the audiospectrograms. The dominant frequency varies from ca. 1890 to 2550 Hz ( Fig. 8B ). The dominant harmonic varies from the fifth to the 38 th harmonic, but it is usually the eighth. There is no clear shift in the relative energy among the bands throughout the call. Most of the call energy is between 1200 and 2800 Hz (ca. six harmonics). There is no clear general FM in the call but there are subtle irregular FM segments throughout the entire call.

Call B ( Fig. 8 E–F and 6C). We examined three recordings, a total of one minute, with ca. 10 calls from one male. All these calls were measured (see Table 2 ). Call duration ranges from 1.269 to 1.727 s. Both call rise and fall are very short and abrupt. There is a long sustain in the call. Usually the amplitude decreases gradually throughout this segment, from the amplitude peak until the end of it. The amplitude peak is at the very beginning of the call duration. The slope of the sustain makes the envelope of the call triangular (pointed right; Fig. 8E ). More than 50 % of the call energy is concentrated in 45 % of the call duration around the amplitude peak. The call has a strong PAM (with silence intervals present between pulses; Fig. 8E, F ). The rate of the PAM is considerably irregular with an average of ca. 19 Hz, forming ca. 30 pulses throughout the call. The envelope of the pulses is variable but it is usually elliptic with the amplitude peak at the middle of the pulse. The last pulse is usually ca. 3.5 times longer than the others. The call is composed of harmonics ( Fig. 6C ). The harmonics are very close to each other and not very clear due to the low fundamental frequency, short pulse duration, and the lack of the wave periodicity throughout the call (deterministic chaos regimes). Audiospectrograms with relatively broad filter bandwidths (e.g., above 100 Hz) can show wave peaks, of some parts of the call with low fundamental frequencies (minimum 107 Hz; see Table 2 ), as broadband pulses (instantaneously high sound-pressure effect; see Littlejohn 2001). The fundamental frequency is around 130 Hz and it is usually absent in the audiospectrograms. The dominant frequency varies from ca. 2060 to 2560 Hz ( Fig. 8F ). The dominant harmonic varies from the seventh to the 57 th, but it is usually around the 15 th harmonic. There is no clear shift in the relative energy among the bands throughout the call. Most of the call energy is between 1700 and 4100 Hz (up to 20 harmonics). There is no clear general FM in the call but there are subtle irregular FM segments throughout the entire call ( Fig. 8F ).

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 6. Multiplicity relationship between “instantaneous” dominant frequency and w of calls B and C of six Physalaemus species. Each graph shows a single call. Call B of P. maculiventris (A), call B of P. erythros (B), call B of P. ruspestris (C), call B of P. nanus (D), call C of P. nanus (E), and call B of P. spiniger (F). 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 8. Calls A and B of Physalaemus rupestris. Oscillograms (A, C, D, and E) and audiospectrograms (B and F). A single typical call A (A and B). Variant A calls (C and D). Note the amplitude modulation resulting in two pulses (C). A single B call (E and F). Horizontal scale bars have 0.05 s (C–D). Filter bandwidth (Hz): 44.9 (B and F).