Review of bioacoustical traits in the genus Physalaemus Fitzinger, 1826 (Anura: Leptodactylidae: Leiuperinae)
Author
Hepp, Fábio
Author
Pombal, José P.
text
Zootaxa
2020
2020-01-20
4725
1
1
106
journal article
24303
10.11646/zootaxa.4725.1.1
67d90a4f-f853-4561-ae9a-c0f596d948ca
1175-5326
3612996
B137F19A-2C50-476C-8F13-4F049253B361
Physalaemus centralis
Bokermann, 1962
We found a single call
type
for the species, referred to as call A. The call is composed of single harmonic note with a very low fundamental frequency. Frequency modulations are subtle (20 Hz), still the call has a general downward FM, with an up-downward FM segment in the first third of the call duration.
FIGURE 31.
Call A of
Physalaemus centralis
. Oscillograms (A and C) and audiospectrograms (B, D, and E). A single typical call (A–B). A variant call with a different envelope (C). Audiospectrograms with apparent bands at a narrow filter (B) and bands not visible at wide filter (D; see filter values below). Sequence with three calls (E); note the frequency modulations (see text). Horizontal scale bars have 0.1 s (C and D) and 0.5 s (E); vertical scale bars have 1 kHz (D) and 0.5 kHz (E). Filter bandwidth (Hz): 34.5 (B and E); 135 (D).
Call A (
Fig. 31
A–E and 24H).
We examined 16 recordings, a total of 36 minutes, with
ca
. 1880 calls from
25 males
. Only some of these calls were measured (see
Table 2
). Call duration varies from 0.404 to
0.550 s
. The call rise is much longer than call fall. Call rise has a short gradual increase followed by a long exponential part (
Fig. 31C
). In some calls the rise remains with very low amplitude until the limit with the sustain, where the amplitude increases abruptly (
Fig. 31A
). The sustain is regular, slightly decreasing towards the end of the call. The call fall is proportionally short and with logarithmic shape. The amplitude peak is at around the middle of the call duration. The envelope varies from elliptic (
Fig. 31C
) to almost rectangular (in calls in which the rise is not gradual;
Fig. 31A
). More than 50 % of the call energy is concentrated in 25 % of the call duration around the amplitude peak. There is no PAM in the call. The call has a harmonic series (
Fig. 24H
). However, due to the low fundamental frequency (see below), the wave peaks are shown as pulses in audiospectrograms at broad filter bandwidth (
e.g.,
above 100 Hz;
Fig. 31E
). The bands are observed in audiospectrograms at narrow filter bandwidth (
e.g.,
below 90 Hz;
Fig. 31B, D
). The fundamental frequency is
ca.
90 Hz. This band and the next harmonic are generally absent in audiospectrograms. There are
ca.
20 emphasized harmonics. The wave periods are regular and harmonics clear throughout the call. The dominant frequency varies from
ca
.
1410 to 1500
Hz (
Fig. 31B
). The dominant harmonic varies from the fourth to the 21
st
, but it is usually between the 15
th
and 18
th
. There is a clear shift in the relative energy among bands; the dominant frequency gets higher toward the end of the call, starting at the fourth, fifth or sixth harmonic and ending at the 15
th
, 19
th
, 20
th
, or 21
st
(
Fig. 24H
,
31B, D
). Most of the call energy is between 600 and 1650 Hz (eight to twelve harmonics). Frequency modulations are subtle and better perceptible in audiospectrograms with wide filter band- widths (
e.g
.,
Fig. 31E
). The call has a general downward FM. Additionally, the calls have an up-downward FM in the first third of the call duration, yielding arc-shaped bands in this part of the call, and a short downward FM at the end (
Fig. 31B, D
). The general downward FM and the initial up-downward FM result in S-shaped harmonics when considering the entire call. There is no PFM.