We present evidence for an incorrect distribution record of Hylodes sazimai and provide a new record of it in the state of Minas Gerais Gerais based on genetic and acoustic data, revisiting the differential diagnosis among its closely related species. The new population is related to the H. sazimai topotypes, with no more than 0.6% of genetic distance. However, the population from Parque Nacional do Itatiaia (PARNA Itatiaia) has a genetic distance varying between 2.7% (2.7–2.8%) from topotypes and 3.3% (3.1–3.3%) from Poços de Caldas specimens. The comparison of these data with the distances between H. sazimai and the other closely related species shows that the population from PARNA Itatiaia is not H. sazimai, nor any other species included in this study. Topotypic H. sazimai has an advertisement call consisting of a sequence of approximately 26 notes lasting around 2 sec and emitted at a rate of 4 calls per minute and 12 notes per second. Hylodes sazimai from Poços de Caldas has an advertisement call consisting of a sequence of about 33 notes lasting around 2 sec and emitted at a rate of 5 calls per minute and 13 notes per second. The random forest approach did not reveal significant discrimination between the populations. Most call features were classified as dynamic for both populations. Because the taxonomic status of the PARNA Itatiaia population is not related to H. sazimai, we suggest a reduction of the northeastern distribution of the species, restricting it to the topotypic locality and Poços de Caldas. Our study reinforces the importance of integrative studies to solve biodiversity crypsis issues and emphasizes the use of detailed acoustic analysis as a powerful tool to diagnosing Hylodes species.