Proceratophrys redacta Teixeira Jr, Amaro, Recoder, Vechio & Rodrigues, 2012

Simões, Cássio Rachid M. A., Pontes, Bruna Elizabeth Silva De, Trevisan, Camila Costa, Abreu, Rafael Oliveira De, Juncá, Flora Acuña, Solé, Mirco, Araújo, Carlos Barros De & Napoli, Marcelo Felgueiras, 2020, The advertisement call of Proceratophrys redacta (Anura, Odontophrynidae), Zootaxa 4750 (3), pp. 447-450 : 447-449

Proceratophrys redacta Teixeira Jr, Amaro, Recoder, Vechio & Rodrigues, 2012

is a dwarf species of Proceratophrys characterized by its small size and by the presence of a row of small round tubercles on the eyelids ( Teixeira Jr et al. 2012). This species is only known from the type locality and surroundings of the municipality of Morro do Chapéu (state of Bahia, Brazil) and inhabits areas of montane forests and adjacent open mesic areas ( Teixeira Jr et al. 2012). To date, natural history data on P. redacta remain limited to that provided in its original description (see Texeira Jr et al. 2012), and its advertisement call remains undescribed.

Here, for the first time, we describe the advertisement call of P. redacta , using sound recordings obtained ca. 25 airline km northwards from the species type locality, in the same mountain range. Furthermore, we compare the advertisement call of P. redacta with calls available in the literature for congeners.

We recorded four calling males of P. redacta for at least five minutes using a Rodes NTG-2 directional microphone coupled to a Tascam DR-40 digital recorder on February 3, 2018. The microphone was 1 m from the recorded individual, and the recordings were built in an uncompressed wav format with a 24-bit resolution and a sampling rate of 44,100 Hz. After all the recordings, we measured the air temperature and air humidity using a Minipa MT-241 thermohygrometer (precision: 1°C and 10%). We collected individuals after the recordings and measured their snout-vent length (SVL) and body mass using an LEE tools analog caliper (0.02 mm of precision) and a digital pocket scale (0.01 g of precision), respectively. The collected individuals were identified by comparisons with the diagnose presented in Texeira Jr et al. (2012). The specimens are housed at the Museu de História Natural da Universidade Federal da Bahia (MHNBA, vouchers numbers: UFBA 15771–15774), and the sound recordings are housed at the MHNBA’s Amphibian Sounds Library (SUFBA, voucher numbers: SUFBA 401–404).

Preceding the acoustic analysis, we edited the recordings through a high pass filter of -18 dB at 150 Hz on Audacity software ( Audacity Team 2017) and normalized the recordings in R software (R Core Team 2018) using the seewave package ( Sueur et al. 2008). We analyzed the acoustic parameters of the advertisement calls with R software (R Core Team 2018) using warbleR ( Araya-Salas & Smith-Vidaurre 2017), tuneR ( Ligges et al. 2018) and seewave ( Sueur et al. 2008) packages. Spectrograms were built in an Asus notebook with an Intel I5 processor using Hanning window, a fast Fourier transform window width of 256, overlap of 80%, and a dynamic range of -40–0 dB. We measured temporal parameters directly on the oscillogram, while spectral parameters were measured on the power spectrum. Our terminology followed the ‘note centered’ approach described by Köhler et al. (2017). We measured call duration (s), call emissions rate (calls/s), number of notes per call, number of pulses per call, pulse emissions rate (pulses/s; calculated by [pulse number - 1]/time interval (s) between the beginning of the first pulse and the beginning of the last pulse), and dominant frequency (Hz). The measured parameters followed those in Nascimento et al. (2019). The description was compared with all other published call descriptions for the Proceratophrys genus (available at Ferreira et al. 2016; Andrade et al. 2018; Mângia et al. 2018; Nascimento et al. 2019). Data are presented as the mean ± standard deviation (minimum–maximum).

We observed P. redacta individuals calling on two nights after sunset (approximately 5: 40 p. m.). On January 27, only one individual was calling (recording was not useful), and on February 3, after a rainy day, we observed at least five individuals (only four recorded) calling near a water spring (11°22’07”S, 41°15’12”W, datum WGS84, 1,128 m a.s.l.) in the Parque Estadual Morro do Chapéu , municipality of Morro do Chapéu , state of Bahia, Brazil. The recorded individuals were close to the near calling male at approximately 0.7 to 1.8 m. They were vocalizing on leaf litter between ferns (UFBA 15771), on mud (UFBA 15772, UFBA 15774), and on moist moss (UFBA 15773). On February 3, we measured the air humidity at 87–89% and the air temperature at 19.5–20.1°C .

We analyzed 61 calls from four individuals (12 calls from UFBA 15771, 10 from UFBA 15772, 13 from UFBA 15773, and 26 from UFBA 15774). The advertisement call of P. redacta is composed of one amplitude-modulated pulsionated note. The majority of the analyzed calls (62%) started with a rising modulation amplitude, and at approximately the middle portion of the call, they presented a maximum amplitude followed by a decreasing amplitude modulation until the end of the call ( fig. 1D ). The advertisement call of P. redacta can be characterized by the following: duration=0.57 ± 0.14 s (0.15– 0.85 s); call rate=0.22 ± 0.23 calls/s (0.01–1.04 calls/s); number of pulses=51.02 ± 12.35 (13–74); pulse rate=89.86 ± 2.93 pulses/s (84.85–106.79 pulses/s); and dominant frequency=1,926 ± 145 Hz (1,658 –2,142 Hz). The waveform, power spectrum and spectrogram of the call are shown in fig. 1 , and the call parameters are detailed in table 1 .

Proceratophrys redacta calls can be easily distinguished from almost all congeners by their higher value of dominant frequency ( P. redacta : 1,658 –2,142 Hz; combined dominant frequencies of congeners: 200–1,590 Hz). Proceratophrys species whose dominant frequency overlaps with P. redacta are P. avelinoi Mercadal de Barrio & Barrio ; P. minuta Napoli, Cruz, Abreu, and Del Grande ; and P. schirchi (Miranda-Ribeiro) . In relation to P. avelinoi (call described by Kwet & Baldo 2003) and P. minuta (call described by Nascimento et al. 2019), the P. redacta call is distinguished by its high pulse emissions rate ( P. redacta =84.85–106.79 pulses/s; P. avelinoi =64–72 pulses/s; and P. minuta =66.8–73.8 pulses/s). Comparisons between P. redacta and P. schirchi (call parameters presented by Nascimento et al. 2019) demonstrated overlap for all measured parameters. Despite the overlap in dominant frequency and pulse emissions rate, overlap occurs only for the extreme values. The higher values of the P. schirchi dominant frequency (1,640 –1,810 Hz) and pulse emissions rate (76.6–85.0 pulses/s) overlap with the lower values of the P. redacta dominant frequency (1,658 –2,142 Hz) and pulse emissions rate (84.85–106.79 pulses/s). Nevertheless, these two species can be morphologically distinguished from each other (see Teixeira-Jr et al. 2012 for morphological comparisons).

Two of the parameters that mainly distinguish the P. redacta advertisement call from that of its congeners (dominant frequency and pulse emissions rate) are recommended for use in taxonomy and are very important for mate recognition in anuran species ( Köhler et al. 2017). Therefore, despite our results showing a small overlap between P. redacta and other Proceratophrys species, differences in dominant frequency and pulse emissions rates seem to be sufficient to allow distinguishing species vocally and can be usefull on taxonomy of the genus.

Figures

FIGURE 1. Advertisement call of Proceratophrys redacta from the municipality of Morro do Chapéu, state of Bahia, Brazil (adult male UFBA 15774, advertisement call SUFBA 404; air temperature=19.5°C; air humidity=89%; body mass=2.42 g; and snout-vent length=28.9 mm). A: Waveform of three calls with the zoomed call highlighted. B: Spectrogram of the highlighted call. C: Power spectrum of the highlighted call. D: Waveform of the highlighted call. E: Photograph of an adult P. redacta male collected during the fieldwork (voucher UFBA 15771).