Revelando a diversidade críptica de um passarinho monotípico (Tachyphonus phoenicius, Aves, Thraupidae) especializado em um hábitat insular na Amazônia

Abstract

Cryptic diversity refers to taxonomic entities under a single nomenclature, with virtually identical phenotypic characters. This concept has been better explored since the advent of tools (mainly molecular) that help in the delimitation and naming of these taxa, even in well-documented groups such as birds. Here, we investigated the taxonomic history and cryptic diversity of a bird considered monotypic, typical of the Amazonian meadows, the red-shouldered tanager Tachyphonus phoenicius Swainson, 1838. This bird has a characteristic wing meeting (dragon) with wide distribution in this insular environment and a controversial classification history. Furthermore, ancient and recent studies suggest the existence of cryptic lineages inserted in this passerine. Based on this, we investigated its taxonomic history in detail, with the result that T. phoenicius does not have a well-defined type locality since its naming by Swainson and that the holotype is probably lost. In this way, we designated duly registered Viruá neotypes and paraneotypes, with morphometric and genetic information (ND2 and ACO1), providing the basis for subsequent taxonomic and systematic studies. We also investigated cryptic diversity in T. phoenicius with morphometric, ND2 and UCE data from previous and new studies, testing hypotheses from two and four distinct populations. For univariate and multivariate morphometric data, we performed an analysis of epaulette coloration classified in 4 levels, Mann-Whitney and Kruskall-Wallis tests with Dunn contrast, principal components and similarity analyses, processed in PAST. For genetic data, we analyzed population structure (STRUCTURE), phylogenetic reconstruction for ND2 (BEAST2) and UCEs (ASTRAL-III), and species delimitation (iBPP). Our results, the largest sampling and integration of morphogenetic data ever documented for the species, indicate important variations in morphological characters in the north-south direction of the Rio Solimões-Amazonas, even in the coloration of the dragona. Genetic analyzes also show a clear differentiation well supported in the same geographic pattern, in addition to evidence of the formation of populations east and west of the Rio Branco, evidencing the polytypic taxonomic status of T. phoenicius, with at least one sp. nov. in the south of the Solimões-Amazonas river, raising relevant implications for the conservation of the Amazonian grasslands and contributions to a better understanding of the biodiversity of avifauna in the Amazon.