Physalaemus maculiventris (A. Lutz, 1925)

We found two different calls, referred to as call A and B. Calls B were common in recordings in which several males were more active and calling close to each other. Calls B are commonly observed after overlapping periods of A calls. Call B resembles a long call A with higher fundamental frequency, pulse-PAM rate, and stronger PFM.

Call A (Fig. 5 A–D and 4B). We examined two recordings, a total of six minutes, with ca. 400 calls from four males. Only some of these calls were measured (see Table 2). Call duration varies from 0.172 to 0.260 s. The rise of the call is longer than the fall; the amplitude peak is approximately at the end of the first three fourths of the call duration. Since both rise and fall are relatively similar in slope and not too different in duration, the envelope of the call is fairly elliptic (Fig. 5A, C). More than 50 % of the call energy is concentrated in 24 % of the call duration around the amplitude peak. The call has a subtle PAM (there is no silence interval between peaks; Fig. 5C). The rate of the PAM is ca. 39 Hz, forming ca. six amplitude peaks throughout the call. The call is composed of usually clear harmonics (Fig. 4B), however, eventual decreases of the wave periodicity make the harmonics less clear. The fundamental frequency is approximately 220 Hz and it can be present with low energy or absent in the audiospectrograms. The dominant frequency varies from ca. 820 to 1510 Hz (Fig. 5B, D). The dominant harmonic varies from the third to the sixth, but it is usually the fifth. There is no clear shift in the relative energy among the bands throughout the call. Most of the call energy is between 700 and 1500 Hz (often comprising five harmonics). The frequency bands have a general upward FM throughout the call with a rapid up-downward FM at the beginning forming arc-shaped bands in this part of the call and a short downward-FM segment at the end (Fig. 5B). There are irregular PFM segments throughout the entire call; these segments are usually synchronic and directly proportional to the PAM (Fig. 5D).

...Continued on the next page

Call B (Fig. 5 E–F and 6A). We examined one recording, a total of one minute, with six calls from two males. Only some of these calls were measured (see Table 2). Call duration varies from 0.375 to 0.675 s. The call rise is longer than the fall with a long regular sustain or shallow valley separating them; the shallow valley yields two amplitude peaks at the beginning and end of the call. The amplitude peak is at around the end of the first two thirds of the call duration (i.e., second amplitude peak). Depending on the slope of the sustain and the difference between the peaks, the envelope of the call can vary from rectangular to triangular (pointed left; Fig. 5E). More than 50 % of the call energy is concentrated in 34 % of the call duration around the amplitude peak. The call has a slight PAM (there is no silence interval between the peaks; Fig. 5E). The rate of the PAM is ca. 32 Hz, forming ca. 13 amplitude peaks throughout the call. The call is composed of harmonics (Fig. 6A). Usually the harmonics are clear, however, eventual decreases of the wave periodicity make the harmonics less clear. 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 123 Hz; see Table 2), as broadband pulses (instantaneously high sound-pressure effect; see Littlejohn 2001). The fundamental frequency is usually ca. 240 Hz and it can be present with low energy or absent in the audiospectrograms. The dominant frequency varies from ca. 1030 to 1310 Hz (Fig. 5F). The dominant harmonic varies from the third to the eighth, but it is usually the fourth or the fifth harmonic. There is no clear shift in the relative energy among the bands throughout the call. Most of the call energy is between 800 and 1600 Hz (ca. three harmonics). The frequency bands have a general upward FM throughout the call with a up-downward FM segment at the beginning forming arc-shaped bands in this part of the call and a short downward FM segment at the end (Fig. 5F). There are irregular PFM segments throughout the entire call; these segments are usually synchronic and directly proportional to the PAM (Fig. 5E, F).