Physalaemus crombiei Heyer & Wolf, 1989

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 : 44-46

Physalaemus crombiei Heyer & Wolf, 1989

We found two different calls, referred to as call A and B. B calls were observed in recordings in which males emitted A calls with very long durations. Calls A and B are composed of harmonics and a single note each. A calls have pulses separated by silence intervals whereas B calls have not. Moreover, B calls have a general upward FM and FM segments (periodic or not) stronger than those of A calls.

Call A ( Fig. 15 A–J and 13C). We examined nine recordings, a total of 20 minutes, with ca. 900 calls from 18 males. Only some of these calls were measured (see Table 2 ). Call duration varies from 0.319 to 0.774 s. The call rise and fall durations are usually similar to each other and they can be gradual or abrupt, linear or logarithmic; there is a long sustain ( Fig. 15A, C, D, E ). This segment can be slightly concave or convex ( Fig. 15D, E , respectively). The amplitude peak is often at around (usually just after) the middle of the call duration. Since both rise and fall are similar in slope and duration, the envelope of the call is fairly elliptic ( Fig. 15E ) but can be rectangular ( Fig. 15C, D ) or triangular (pointed left; Fig. 15A ) depending on the shape of sustained segment and the position of the amplitude peak of the call. More than 50 % of the call energy is concentrated in 43 % of the call duration around the amplitude peak. The call has a strong PAM (with silence intervals present between pulses; Fig. 15 A–J). The rate of this PAM is ca. 25 Hz, forming ca. nine pulses throughout the call. Except for the last pulse, the rise of the pulses is longer than the fall and the amplitude peak is at around the end of the first two thirds of the pulse duration ( Fig. 15F ). The last pulse has the inverse envelope with amplitude peak at its outset ( Fig. 15F ). In some calls, the last pulse is notably longer than the others ( Fig. 15A, B, C, E, F, G, I, J ). Silence intervals are present between pulses, ca. tenfold shorter than pulse duration ( Fig. 15 A–J). The call has a harmonic series ( Fig. 13C ). The fundamental frequency is ca. 370 Hz and this band can be present with low energy or absent in the audiospectrograms. The wave periods are very regular and the harmonics are clear throughout the call. Jumps of the fundamental frequency can be present between the first pulses. The dominant frequency varies from ca. 1010 to 1380 Hz ( Fig. 15B ). The dominant harmonic varies from the third to the fourth, but it is usually the third. There is no clear shift in the relative energy between the bands throughout the call. Most of the call energy is between 900 and 1300 Hz (two harmonics). The frequency bands have a general upward FM throughout the call and short downward FM at the end ( Fig. 15B, G, H, I ). Additionally, there is PFM throughout the call, which is directly proportional to the synchronic pulse-PAM ( Fig. 15B, G, H, I, J ).

Call B ( Fig. 15 K–N and 16A). We examined one recording, a total of five minutes, with two calls from one male. Most of these calls were measured (see Table 2 ). Call duration varies from 0.709 to 0.945 s. The envelope of the call is variable; call rise and fall are short. There can be more than one sustain, with different amplitudes ( Fig. 15K, M ). Usually, the first has lower amplitude ( Fig. 15K ). The amplitude peak is at around the middle or beginning of the call duration. The envelope can be classified as elliptic, triangular (pointed right; Fig. 15M ) or rectangular ( Fig. 15K ). More than 50 % of the call energy is concentrated in 30 % of the call duration around the amplitude peak. One call clearly shows a section with a slight PAM (there is no silence interval between the amplitude peaks; Fig. 15K ). The rate of this PAM is ca. 19 Hz, forming ca. seven emphasized peaks at the middle of the call duration. The call has a harmonic series ( Fig. 16A ). The fundamental frequency is ca. 340 Hz and this band can be present with low energy or absent in the audiospectrograms. One call shows a sudden jump of the fundamental frequency at the end of the call. The wave periods are regular and then the harmonics are clear throughout the call. The dominant frequency varies from ca. 1020 to 1160 Hz ( Fig. 15L ). The dominant harmonic is the third. There is no clear shift in the relative energy between the bands throughout the call. Most of the call energy is between 600 and 2000 Hz (ca. five harmonics). The frequency bands have a general upward FM throughout the call and short downward FM at the end ( Fig. 15L, N ). Additionally, there is PFM throughout the call, which is directly proportional to the synchronic pulse-PAM where it is present (15K–N).

Figures

FIGURE 13. Multiplicity relationship between “instantaneous” dominant frequency and w of calls A of eight Physalaemus species. Each graph shows a single call A of: P. nanus (A), P. spiniger (B), P. crombiei (C), P. signifer (D), P. bokermanni (E), P. angrensis (F), P. atlanticus (G), P. moreirae (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. nanus; A).

FIGURE 15. Calls A and B of Physalaemus crombiei. Oscillograms (A, C, D, E, F, K, and M) and audiospectrograms (B, G, H, I, J, L, and N). A single typical call A (A and B). Variant calls A with different number of pulses, pulse durations, and interpulse intervals (C–I). Last three pulses of the call A (F–J). Two B calls with different envelope and spectral features (K–N). Note that there is no silence intervals within call B (K–N). Horizontal scale bars have 0.1 s (C–E, G–I, M–N) and 0.05 s (F and J); vertical scale bars have 1 kHz. Filter bandwidth (Hz): 90.6 (G and J); 79.3 (B); 84.6 (I); 67.4 (L and N).

FIGURE 16. Multiplicity relationship between “instantaneous” dominant frequency and w of calls B of five Physalaemus species. Each graph shows a single call B of: P. crombiei (A), P. signifer (B), P. bokermanni (C), P. angrensis (D), and P. moreirae (E). 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.