Sistemática e biogeografia do complexo de espécies Thamnophilus doliatus

Abstract

Defining species boundaries remains a challenge in systematic studies, particularly when dealing with recently diverged lineages or taxa with conspicuous morphology. Among the highly diverse suboscines of the New World, the polytypic species Thamnophilus doliatus, comprising twelve subspecies, exemplifies this complexity. In this dissertation, we investigate lineage boundaries within this taxon using an integrative approach that combines genetic, morphological, and acoustic data. We further compare the identified lineages with previously described subspecies. Our results reveal the presence of six wellsupported clades within the T. doliatus complex, characterized by recent divergence (Pleistocene) and haplotype sharing. Additionally, we identify several previously unrecognized contact zones between lineages. Morphometric analyses indicate differentiation in male bill size; however, overall morphology does not exhibit clear divergence. Temporal and spectral acoustic parameters also show differences among the focal clades. The data suggest a high level of taxonomic complexity within T. doliatus, as evidenced by significant genetic differentiation. Specifically, the subspecies T. doliatus intermedius, T. doliatus nigricristatus, and T. doliatus capistratus are supported as distinct lineages, whereas morphological overlap is observed between T. doliatus capistratus and T. doliatus difficilis/radiatus. Although birds are among the bestdocumented taxonomic groups, our findings highlight previously underestimated cryptic diversity in the Neotropical region. Large-scale genomic and phenotypic studies will be essential for addressing the taxonomic gaps identified in this study.