The Distress Calls of \u3cem\u3eLeptodactylus chaquensis\u3c/em\u3e Cei, 1950 and \u3cem\u3eLeptodactylus elenae\u3c/em\u3e Heyer, 1978 (Anura: Leptodactylidae)
We describe the distress calls of Leptodactylus chaquensis and Leptodactylus elenae. They each consist of a single, long, tonal sound with complex harmonic structure and complex frequency modulation. The distress calls of both species are different from their respective advertisement calls. Moreover, there are also clear interspecific differences. Harmonic frequencies in L. elenae are higher, there are fewer emphasized harmonics and the call is shorter and repeated at a higher rate (sometimes paired) than the call of L. chaquensis. Call duration, call rate, and position of the dominant harmonic change with the strength of the stimulus that the individuals are under; therefore, they are more variable than their respective advertisement calls