Physalaemus olfersii (Lichtenstein & Martens, 1856)

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 : 76

Physalaemus olfersii (Lichtenstein & Martens, 1856)

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 very long duration and a slight PAM (no silence intervals between pulses). It has an irregular and strong PFM throughout the call. The bands have no general FM or have only a slight FM, which is usually upward.

Call A ( Fig. 44 A–D and 42C). We examined 13 recordings, a total of 35 minutes, with 332 calls from 31 males. Only some of these calls were measured (see Table 2 ). Call duration varies from 3.530 to 4.837 s. Call rise and fall are very short and similar to each other in duration. The limit between the call rise and sustain is not clear in calls with triangular envelope ( Fig. 44A ). There is a long sustain. This segment is usually regular and almost flat (slightly decreasing towards end of the segment – Fig. 44C ), but some calls have very inclined sustains, where the beginning of the segment has low amplitude and gradually increases towards its end ( Fig. 44A ). The amplitude peak is at around the end of the first tenth or at the very end of the call duration. The envelope of the call varies from rectangular ( Fig. 44C ) to triangular (pointed left; Fig. 44A ). More than 50 % of the call energy is concentrated in 46 % of the call duration around the amplitude peak. The call can have a slight PAM (silence intervals are absent between peaks). The rate of the PAM is ca. 11 Hz, forming ca. 50 cycles throughout the call. The cycle rise and fall are similar and the amplitude peak is at the middle of the cycle duration. The call has a harmonic series ( Fig. 42C ). The fundamental frequency is ca. 150 Hz. The first seven harmonics have very low energy or are absent in the audiospectrogram. There are ca. 12 adjacent emphasized harmonics. The wave periods are usually regular and harmonics are clear throughout the call. However, some calls have deterministic chaos regimes in several parts, mainly at their outset ( Fig. 44B ). The dominant frequency varies from ca. 1570 to 1870 Hz ( Fig. 44B ). The dominant harmonic varies from the ninth to the 19 th, but it is usually between the ninth and 12 th ( Fig. 42C ). There is no clear shift in the relative energy between the bands throughout the call. Most of the call energy is between 1100 and 2150 Hz (12 harmonics). Calls have no general FM ( Fig. 44D ), or have only a slight general FM, usually upward ( Fig. 44B ), but sometimes downward. There is usually a short downward FM at the end of the call ( Fig. 44B ). Additionally, there is a strong PFM throughout the call, which is usually independent, but it is directly proportional and synchronic to PAM when it is present ( Fig. 44B, D ).

Figures

FIGURE 42. Multiplicity relationship between “instantaneous” dominant frequency and w of calls A of eight Physalaemus species. Each graph shows a single call A of P. orophilus (A), P. lateristriga (B), P. olfersii (C), P. riograndensis (D), P. biligonigerus (E), P. marmoratus (F), P. santafecinus (G), P. carrizorum (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 call B of P. ephippifer).

FIGURE 44. Call A of Physalaemus olfersii. Oscillograms (A and C) and audiospectrograms (B and D). A typical call (A–B). A variant call with a different envelope and spectral features (C–D). Note the deterministic chaos at the beginning of the call (B). Note the higher noise level in the call and the irregular PFM (D). Horizontal scale bars have 0.5 s; vertical scale bars have 1 kHz. Filter bandwidth (Hz): 25.4 (B and D).