Systematic review of Rhynchocyclus olivaceus (Aves: Rhynchocyclidae) based on a multi-character approach

Birds are the group for which the largest amount of evolutionary and ecological information is available. However, recent studies have shown that many polytypic species are in fact complexes of species, thus revealing a “hidden” diversity within already recognized species. The species Rhynchocyclus olivaceus (Aves: Rhynchocyclidae) has nine currently recognized subspecies, but so far no phylogenetic hypothesis exists for the evolutionary relationships among them. To estimate a phylogeography for the group we sequenced three mithocondrial genes and two nuclear loci, from five R. olivaceus subspecies (n=89). The obtained phylogeny pointed to several taxonomic inconsistencies within R. olivaceus evolutionary history. First, the analysis suggest that the species is paraphyletic. Second, two subspecies of R. olivaceus are not monophyletic; R. o. aequinoctialisis polyphyletic and divided into five distinct phylogroups (all of them located in the Napo and Inambari centers of endemism); and R. o. sordidus is paraphyletic with respect to the Atlantic Forest endemic nominate R. o. olivaceus. Although the phylogeny indicates the need of taxonomic updates, the large groups found within “R. olivaceus” are apparently morphologically very similar. However, a preliminary acoustic analysis suggest that these groups have conspicuously distinct vocalizations consistent with genetic differences, reinforcing the cryptic nature of the speciation process in the group.