Scinax acuminatus

(fig. 1A).

In Aquidauana (MS), one male of Scinax acuminatus (38.1 mm SVL; one male) was recorded while calling hidden on grass vegetation about the soil level at the margins of a small dammed stream and another one while calling perched on a tree trunk about 0.2 m above soil at the margins of a natural swamp area (ca. 20º28’S, 55º46’W, 150 m asl).

The advertisement call (fig. 2A; Table 1) consists of a single note, with a mean of 32.6 pulses per call, practically without inter-pulse interval. The calls had a mean duration of 666±29 ms, with a call rate of 25.5 calls/min. The frequencies ranged between 0.64–5.03 kHz and the dominant frequency around 0.83–1.56 kHz. Calls also had power between 2.59–3.77 kHz, but in the most of analyzed calls this band presented much less energy than the dominant frequency band.

The first pulses of most calls and sometimes 2nd and 3rd pulses presented lesser intensity and energy (relative amplitude) in relation to the remaining ones. Calls were characterized by distinguishable ascendant amplitude modulation from the first to the 3rd–4th pulse.

One additional record of S. acuminatus (unvouchered specimen) from Porto Murtinho (MS) was kindly provided by F.L. Souza, but due the unknown nature of the devices used in the recording, the only parameters analyzed from this call were call duration, pulse number and call rate. This call and those from Aquidauana were considered together because totally overlapped in the parameters measured (see Table 1).