Trabalho de Conclusão de Curso (Graduação)In this paper, we describe for the first time the advertisement call of three Elachistocleis species (E. 28 surumu, E. magna, E. matogrosso); and we redescribe the calls of two species (E. helianneae, E. 29 muiraquitan). Additionally, we evaluate intraspecific variation in morphology and color patterns, 30 and comment on the species diagnosis in the genus. The advertisement call of the five species of 31 Elachistocleis have a stereotyped temporal and spectral structure, which consists of a long sustained 32 multipulsed note with an upsweep in frequency at the onset, followed by a constant frequency along 33 the note, and are emitted at irregular intervals. The newly collected series of Elachistocleis in 34 northern and western Brazil showed intraspecific variation in morphology and coloration that had 35 not been previously reported. Coloration was listed as a diagnostic feature in species original 36 descriptions, but our series exhibited color patterns somewhat variable within each species, and 37 sometimes did not allow for species differentiation. Our results indicated that the three species with 38 greater degrees of morphological resemblance (E. helianneae, E. matogrosso, E. muiraquitan) 39 differed in microtemporal and spectral traits of their advertisement calls. Moreover, the 40 microtemporal trait of pulse duration in E. helianneae was divergent, lasting approximately double 41 the duration of pulse in the calls of the other four species studied. Therefore, pulse duration might 42 be informative to the assignment of specimens/populations to E. helianneae based on this 43 distinctive acoustic feature, a species widely distributed across Amazonian lowland forests and 44 Amazonian savannas in northern South America. Our results bring novelties on species diagnosis 45 and intraspecific variation in Elachistocleis, based on acoustic evidence and 46 morphological/chromatic patterns, and accentuate the importance of comprehensive assessments for 47 accurate species-level identification in this genus of Neotropical frogs
