Vocalizations of Atelopus ignescens (Cornalia, 1849): The repertoire of a resilient species that whispers not to disappear

Abstract

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.