Taxonomy and conservation: A tale of two tinamou species groups (Tinamidae, Crypturellus)

Species delimitation has important consequences for the management of endangered species. Species-level taxonomy in the genus Crypturellus (Tinamidae) has been based largely on plumage characters and species limits in several groups have been difficult to establish. Because some of the forms of uncertain taxonomic status are currently threatened with extinction, a basic understanding of species limits is crucial not only for taxonomists but also for conservation biologists and managers. We analysed vocal variation to assess species limits in two Crypturellus species-groups, the red-legged complex (Crypturellus erythropus and allied forms) and the brown tinamou Crypturellus obsoletus. In the red-legged complex, where several species-level taxa have been recognized by some authors, there is no obvious geographic variation in vocalizations and populations appear mostly continuously distributed, with plumage variation largely explicable in terms of environmental conditions. In the brown group, a single species is recognized, but we found marked geographic variation in vocalizations and populations have disjunct distributions; we propose that at least one of the populations in this group likely merits recognition as a separate species. We conclude that incomplete knowledge of patterns of variation in relevant traits in addition to the momentum carried by traditional taxonomy may potentially mislead conservation actions.