Divergent Spatial Patterns of Acoustic Variation in the Red-Shouldered Spinetail Synallaxis hellmayri and the Sooty-Fronted Spinetail S. frontalis (Furnariidae)

Doi: https://doi.org/10.13157/arla.73.1.2026.ra5

Authors: Helon Simões Oliveira, Elpídio Vicente dos Santos-Júnior and Luiz dos Anjos

E-mail: oliveira.helon.s@gmail.com

Published: Volume 73.1, January 2026. Pages 81-91.

Language: English

Keywords: acoustic signals variation, bioacoustics, isolation by distance, spatial structure and suboscines

Summary:

Patchy distributions associated with specialised habitats often lead to vocal variation and, ultimately, speciation. This study investigates the influence of spatial structure on vocal divergence among populations of two Synallaxis species: S. frontalis has an extensive and continuous distribution, whereas S. hellmayri is endemic to the Brazilian Caatinga and exhibits a restricted, disjunct distribution. The two species co-occur in sympatry in parts of northeastern Brazil. The results indicate that acoustic differentiation in S. hellmayri is consistent with isolation by distance.

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