Short Communication |
Corresponding author: Diego Batallas ( bioandino_kakaram@hotmail.com ) Academic editor: Bibiana Rojas
© 2024 Diego Batallas, Juan M. Guayasamin, Mateo A. Vega-Yánez.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Batallas D, Guayasamin JM, Vega-Yánez MA (2024) Vocalizations of Atelopus ignescens (Cornalia, 1849): The repertoire of a resilient species that whispers not to disappear. Herpetozoa 38: 421-428. https://doi.org/10.3897/herpetozoa.37.e134923
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The Atelopus (or harlequin frogs) have become a symbol of the ongoing efforts to conserve biodiversity in Ecuador over the past few decades. Atelopus ignescens, also known as jambato, was previously considered to be an extinct species until it was rediscovered in the Andean locality of Angamarca, Ecuador. This study presents and describes the calls of Atelopus ignescens for the first time. These are low intensity sounds that comprise a repertoire of three distinct call types: tonal, short and pulsed call. They have different spectral and temporal characteristics. The most notable difference in their structure is the presence or absence of pulses and the frequency modulation observed in tonal calls. In terms of spectral characteristics, the mean dominant frequency is 1.7 kHz, with up to 11 harmonics visible. A peculiar feature of the Jambato is the absence of a tympanic middle ear, a characteristic observed in the majority of Atelopus species. The absence of these structures, however, does not mean that harlequin toads are deaf since they seem to have extratympanic mechanisms of audition. It is our hope that our contribution will stimulate further research into the bioacoustics and behavior of this endangered and relatively unknown group of anurans.
acoustic communication, bioacoustics, harlequin frogs, jambato, vocal repertoire
Atelopus ignescens (Cornalia, 1849) is a species of diurnal anuran endemic to Ecuador that belongs to the family Bufonidae. The species is characterized by a medium size, a black coloration, and a reddish belly (
The behavior of the Atelopus species is characterized by multimodal communication, which integrates auditory and visual signals (
The majority of Atelopus species lack a tympanic middle ear (
We recorded vocalizations of the jambato from the Andean locality of Angamarca, province of Cotopaxi, Ecuador (1°7'51.31"S, 78°54'16.85"W; 2962 m; Fig.
The vocalizations of an uncollected adult male of A. ignescens were recorded between 10:00–12:00 on December 8, 2021. The male was calling from grasslands and herbaceous vegetation at ground level. The calls were recorded using a cell phone, saving the audio files in FLAC format at a sampling rate of 44.1 kHz and 24 bits resolution. Prior to analysis, the audio files were converted to the WAV format and edited using the Adobe Audition CS6 software. The recordings are deposited at the Laboratorio de Biología Evolutiva de la Universidad San Francisco de Quito (
The spectral and temporal parameters of calls were analyzed with the software Raven 1.6 (K. Lisa Yang Center for Conservation Bioacoustics at the Cornell Lab of Ornithology 2024). We used a Hann window with 256 samples of the Fast Fourier Transformation (FFT), a 90% overlap, and a frequency grid with 512 samples of the Discrete Fourier Transformation (DFT). The analyzed parameters were: Call duration (CD), Rise time (RT), Decay time (DT) Intervals between calls (IC), Call rate (CR) Notes/call (NC), Note Duration (ND), Intervals between notes (IN), Note rate (NR) Pulse/note (PN), Pulse duration (PD) Intervals between pulses (IP), Pulse rate (PR), Dominant frequency (DF), Minimum frequency (MinF), Maximum frequency (MaxF), Frequency modulation (FM), Number of visible harmonics (NH), Harmonic frequency range, series of values that correspond to multiples of the fundamental frequency, with the value of the second and last harmonic taken as the reference (HRF). Definitions, terminology, and measurements of acoustic parameters follow the terms of
The vocalizations of Atelopus ignescens comprises three distinct call types, ranging from non-pulsed to pulsed calls (Fig.
Spectral and temporal values of Atelopus ignescens. The abbreviations used in the parameters correspond to: DF = Dominant frequency; MinF = Minimum frequency; MaxF = Maximum frequency; FM = Frequency modulation; NH = Number of visible harmonics; HRF = Harmonic Frequency Range; CD = Call duration; RT = Rise time; DT = Decay time; IC = Intervals between calls; CR = Call rate; NC = Notes/call; ND = Note duration; IN = Intervals between notes; NR = Note rate; PN = Pulses/Note; PN = Pulse duration; IP = Interval between pulses; PR = Pulse rate. The abbreviations used in the call types correspond to: Tc = Tonal call; Stc = Short call; Pc = Pulsed call. The abbreviations used in units of measurement correspond to: kHz = kilohertz; ms = milliseconds; s = seconds; /min = per minute; /s = per second. We indicate: number of specimens/calls/notes/pulses.
Parameters | Call (general) | Call Types | ||
---|---|---|---|---|
n = 1/15/15/27 | Tc | Sc | Pc | |
DF (kHz) | 1.5‒1.8 (1.7 ± 0.07) | 1.64‒1.81 (1.71 ± 0.06) | 1.46‒1.81 (1.60 ± 0.09) | 1.55‒1.72 (1.68 ± 0.05) |
MinF (kHz) | 1.03‒1.64 (1.50 ± 0.12) | 1.55‒1.72 (1.64 ± 0.08) | 1.29‒1.55 (1.44 ± 0.06) | 1.03‒1.64 (1.51 ± 0.14) |
MaxF (kHz) | 1.55‒2.07 (1.78 ± 0.12) | 1.64‒1.89 (1.71 ± 0.10 | 1.55‒1.98 (1.70 ± 0.10) | 1.72‒2.07 (1.83 ± 0.12) |
FM (Hz/ms) | 0‒14.38 (5.64 ± 4.26) | 0.27‒1.56 (0.91 ± 0.48) | 1.71‒14.38 (7.93 ± 3.34) | 0‒0.92 |
NH | 5‒11 (8.86 ± 1.63) | 6‒10 (9.67 ± 0.52) | 8‒11 (9.76 ± 0.83) | 5‒10 (8.11 ± 1.80) |
HRF (kHz) | 2.93‒17.14 | 3.27‒17.05 | 2.93‒17.05 | 3.93‒17.14 |
CD (ms) | 27‒1716 (370 ± 460.98) | 111‒322 (209.33 ± 81.94) | 21‒51 (33.82 ± 10.20) | 189‒137 |
RT % | 18‒91 (42.68 ± 16.44) | 18‒52 (35.75 ± 14.2) | 30‒70 (47.63 ± 11.13) | 20‒67 (35.83 ± 12.25) |
DT% | 9‒82 (57.32 ± 16.44) | 48‒82 (64.25 ± 14.2) | 30‒70 (52.38 ± 11.13) | 33‒80 (64.17 ± 12.25) |
IC (s) | 2283‒19178 (7465.54 ± 5193.34) | – | – | – |
CR (/min) | 3.13‒25.97 (11.38 ± 7.19) | – | – | – |
NC | 1‒4 (1.56 ± 0.89) | – | – | – |
ND(ms) | 21‒266 (66.33 ± 72.83) | – | – | – |
IN (ms) | 41‒612 (418.11 ± 170.87) | – | – | – |
NR (/s) | 1.57‒10.87 (2.87 ± 3.01) | – | – | – |
PN | 13‒15 | – | – | – |
PD (ms) | 3‒21 (7.67 ± 4.26) | – | – | – |
IP (ms) | 2‒7 (4.76 ± 1.33) | – | – | – |
PR (/s) | 62.5‒142.86 (90.20 ± 24.74) | – | – | – |
The vocalizations of Atelopus ignescens lack a stereotyped structural pattern. They are classified into three distinct types of calls based on their structural and temporal characteristics. Two of the types of vocalizations are non-pulsed calls. 1) Tonal calls (Tc; Fig.
In this study we present for the first time the description of the spectral and temporal parameters of Atelopus ignescens calls. A repertoire composed of three structural calls types (i.e., tonal call, short call, pulsed call). The vocalizations described in previous studies indicate that species of the genus Atelopus have more than one call type in their repertoire (e.g. Lötters et al. 1999;
The vocalizations of Atelopus species from Ecuador remain largely unknown, with only those of Atelopus exiguus having been described (
It is noteworthy that the Jambato, like the majority of the genus Atelopus, is distinguished by the absence of a tympanic middle ear (
Atelopus ignescens has become the most representative species for conservation in Ecuador and the Neotropics. Beyond behavioral characteristics, we endow this iconic species with an acoustic identity. We hope that this contribution will establish a baseline for acoustic knowledge of this species, thus facilitating future monitoring and discovery of new populations using passive acoustic methods. Furthermore, acoustic data may serve as a crucial component in evaluating the potential taxonomic issues that remain unresolved in this species (see
First of all, we thank the community of Angamarca for their collaboration and interest in the conservation of the Jambato. We thank the members of the Alianza Jambato, with whom we had the opportunity to embark on fieldwork and engage in shared experiences. To Mario Yánez, for his valuable stories and advice on the conservation of this species, which gave us enough encouragement to shape this work. Special thanks to Laura González of the Fonoteca Zoológica de Madrid for her assistance in the assignment of collection numbers and the generation of QR codes. We thank Bibiana Rojas and two anonymous reviewers for their valuable and constructive comments that helped to improve the quality of this manuscript. This study was partially funded by Universidad San Francisco de Quito USFQ (Grants HUBI 5466, 16871, 17857). We also extend our appreciation to all the researchers around the globe for their efforts over the past decades to prevent the extinction of this species.
Recordings of an uncollected specimen of Atelopus ignescens. The associated codes correspond to three recordings, which were deposited at the Laboratorio de Biología Evolutiva (LAB) and are available at the Fonoteca Zoológica de Madrid (FZ):
Codes correspond to three recordings, available at the Fonoteca Zoológica de Madrid (FZ). A.