Geographic structure and acoustic variation in populations of Scinax squalirostris (A. Lutz, 1925) (Anura: Hylidae)

The advertisement call contains spectral and temporal information, which are used by frogs in different social contexts. We analysed the variation of advertisement calls among eleven populations of Scinax squalirostris along its broad distribution area, examining geographical patterns (latitude, longitude and altitude) related to this variation. We found that parameters responsible for advertisement call variation among populations were call duration and number of pulses. Individuals from Cristalina municipality (state of Goias, Brazil) showed the greatest amount of differences in acoustic parameters among populations studied, suggesting that it could even be a distinct species. We found a geographic pattern between dominant frequency and latitude, with lower values found further north. The variability of call parameters of S. squalirostris populations was not explained by geographic distance alone, suggesting that stochastic events, such as vicariance and/or local selective pressures could have influenced their vocal repertoire historically.