Physalaemus henselii (Peters, 1872)

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 : 55

Physalaemus henselii (Peters, 1872)

We found a single call type for the species, referred to as call A. The call is composed of a sequence of pulses (i.e., pulse-PAM). The call is spectrally polymorphic; some calls have pulses with sidebands.

Call A ( Fig. 23 A–F and 24A). We examined two recordings, a total of four minutes, with ca. 200 calls from six males. Only some of these calls were measured (see Table 2 ). Call duration varies from 0.289 to 0.493 s. The call rise is usually very abrupt and shorter than the call fall ( Fig. 23C ), which has an exponential shape. The call rises are longer and more similar to falls. The sustain varies from flat to very steep in shape. The envelope of the call is elliptic, rectangular ( Fig. 23C ), or triangular (pointed left; Fig. 23A ). More than 50 % of the energy is concentrated in 53 % of the call duration around the amplitude peak. The call has a strong PAM (with silence intervals present between pulses; Fig. 23 A–F). The rate of the PAM is ca. 54 Hz, forming ca. 20 pulses throughout the call. The envelope of the pulses is variable; however, the pulse rise is usually shorter than the fall, with amplitude peak at the beginning of the pulse. Silence intervals are present between pulses, with durations slightly longer than pulse duration except between the first pulses, where the intervals are very short or even absent (pulses are juxtaposed; Fig. 23A, C, D ). The call has a harmonic series ( Fig. 24A ). The fundamental frequency is at ca. 1900 Hz and this band is also the dominant frequency (see below). The wave periods are regular and harmonics are clear throughout the call. The call shows an additional frequency series with bands separated by ca. 250 Hz series produced by a PAM present within pulses ( Fig. 23E, F ). This series is very variable (30 to 550 Hz) and it is not multiple of the harmonic series. Both seem to be independent of each other. Therefore, we called the 250-Hz bands as sidebands. The short duration of the pulses makes the bands broad with narrow intervals. In parts where two pulses are juxtaposed, or at least very close to each other, the wave periods are less regular, the harmonics can be less clear with deterministic chaos ( Fig. 23E ). The dominant frequency varies from ca. 1690 to 2160 Hz ( Fig. 23B ). The first harmonic is the dominant. There is no clear shift in the relative energy among the bands throughout the call. Most of the energy is concentrated between 650 and 2600 Hz (one harmonic). Most of the call energy is between 1400 and 2400 Hz. There is usually neither a clear general FM nor other shorter FM segment in the call. Some calls, mainly those with juxtaposed pulses, show a slight PFM following the PAM (see beginning of the call in Fig. 23E ).

Figures

FIGURE 23. Call A of Physalaemus henselii. Oscillograms (A, C, and D) and audiospectrograms (B, E, and F). A single typical call (A–B). A variant call with a different envelope (C and E). Last pulses of a call (D and F). Horizontal scale bars have 0.1 s (C and E) and 0.02 s (D and F); vertical scale bars have 1 kHz. Filter bandwidth (Hz): 135 (B); 92.1 (F); 69 (E).

FIGURE 24. Multiplicity relationship between “instantaneous” dominant frequency and w of calls A of eight Physalaemus species. Each graph shows a single call A of P. henselii (A), P. albonotatus (B), P. cuqui (C), P. atim (D), P. albifrons (E), P. erikae (F), P. kroyeri (G), P. centralis (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. The heterogeneity of the factors in P. henselii (A) suggests sidebands.