Physalaemus ephippifer (Steindachner, 1864)

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 : 66

Physalaemus ephippifer (Steindachner, 1864)

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 triangular envelope that resembles an arrow-like shape. There is usually a slight PAM (without silence intervals) in the final three fourths of the call duration. The call has a general downward FM, with an up-downward FM segment in the first third or first half of the call duration. Subharmonics are always present in the first half of the call.

Call A ( Fig. 34 A–F and 33B). We examined two recordings, a total of one minute, with ca. 130 calls from six males. Only some of these calls were measured (see Table 2 ). Call duration varies from 0.466 to 0.523 s. The call rise and fall are similar in duration and shape (exponential). The sustain is composed of a long and deep valley (i.e., with a concave shape; Fig. 34A, C ). The envelope varies from elliptic to triangular (pointed right). Due to the concave shape of the sustain, the triangular shape of some calls resembles an arrow ( Fig. 34A ). The amplitude peak is at the end of the first fourth of the call duration. More than 50 % of the call energy is concentrated in 38 % of the call duration around the amplitude peak. Some calls have an intermediate PAM only in the final three fourths of the call duration (there is no silence interval between amplitude peaks; Fig. 34A ). The rate of the PAM is ca. 26 Hz, forming ca. eight cycles throughout part of the call where the PAM is present. The cycle rise and fall are similar, with amplitude peak at the middle of the cycle. The call has a harmonic series ( Fig. 33B ). The fundamental frequency is ca. 590 Hz and approximately the first eight harmonics are emphasized. The wave periods are regular and harmonics are clear throughout the call. Subharmonics (f 0 1/2) are present in ca. the first third or half of all calls examined ( Fig. 34B, E, F ). The dominant frequency varies from ca. 820 to 2630 Hz. The dominant harmonics are the first, third, fourth, fifth or sixth (usually the first or sixth; Fig. 33B , 34B ). At the beginning of the call the subharmonic 1.5 is the dominant band ( Fig. 34B, F ). There is a clear shift in the relative energy among the bands in the second half of the call; the dominant frequency gets higher toward the end of the call, starting at the first harmonic, moving to the fifth, and ending at the sixth; thenceforth, it dominant frequency gets lower, moving to the fourth or third harmonic ( Fig. 33B , 34B ). Most of the call energy is between 550 and 2750 Hz (three to five harmonics). The call has a general downward FM ( Fig. 34B, E ). Additionally, calls have an up-downward FM in the first third or half of the call duration, yielding arc-shaped bands in this part of the call and a short downward FM at the end ( Fig. 34B, E ). The general downward FM and the initial up-downward FM result in S-shaped harmonics when considering the entire call. Calls have a PFM throughout the second half of the call, which is inversely proportional and synchronic to the PAM ( Fig. 34A, B ).

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 34. Call A of Physalaemus ephippifer. Oscillograms (A, C, and D) and audiospectrograms (B, E, and F). A single typical call with PAM and PFM (A–B).A variant call with a different envelope without clear PAM or PFM (C–E). Middle of the call with the transition moment between the segments with and without subharmonics (D–F). Horizontal scale bars have 0.1 s (C and E) and 0.05 s (D and F); vertical scale bars have 1 kHz. Filter bandwidth (Hz): 84.6 (B); 90.6 (E); 61.9 (F).