The Advertisement Call of Proceratophrys minuta Napoli, Cruz, Abreu, and Del Grande, 2011 (Anura: Odontophrynidae), with Comments on Acoustic Parameters in the Genus

Proceratophrys minuta is known from two localities in the state of Bahia, northeastern Brazil. Information on the tadpoles and natural history of adults and larvae is available in the literature, but its advertisement call remains undescribed. Herein, we describe the advertisement call of P. minuta on the basis of four males recorded at the type locality in the municipality of Miguel Calmon, state of Bahia, Brazil. The advertisement call consists of one note with 30–52 pulses and duration of 0.4–0.72 s. The pulses usually present shorter attack than decay, with amplitude varying throughout the call. The dominant frequency over the course of the call is 1.98–2.07 kHz. The advertisement call of P. minuta is compared with available call descriptions of 25 species of Proceratophrys. It is promptly diagnosed from the calls of almost all congeners by presenting the highest dominant frequency, except for P. avelinoi, from which P. minuta can be distinguished on the basis of qualitative parameters (pulse amplitude modulation) and pulse duration. All Proceratophrys species share the following structural features of the advertisement call: notes composed of regularly repeated pulses with amplitude modulation throughout the calls and low dominant frequencies varying from 0.2–2.3 kHz. The advertisement call differs among species of Proceratophrys in the general shape of the call envelope due to distinct patterns of amplitude modulation, being either gradually modulated or abruptly modulated. We tested and obtained negative correlation between species dominant frequencies and body size in Proceratophrys, drawing attention to the importance of body size in the evolution of vocalization. Furthermore, we observed high acoustic similarities among phylogenetically distant species, indicating that quantitative parameters of the call are not likely to predict phylogenetic relatedness. Nevertheless, qualitative characters might recover the phylogenetic relationship among Proceratophrys species, and, further, they might elucidate how the the advertisement call encodes crucial information for mate recognition and discrimination.