Advances on tinamou phylogeny: an assembled cladistic study of the volant palaeognathous birds

Tinamous are volant terrestrial birds, endemic to the Neotropics. Here, an inclusive phenotype-based phylogenetic study of the interrelationships among all extinct and living species of tinamous is conducted. In this cladistic analysis, results are compared between main character subsets and with previous molecular studies. Special attention is paid to character definition and scoring of integumentary and behavioural characters: transformation costs are applied to analyse egg coloration and plumage characters-on the basis of pigment composition and overlap of pigmentation patterns respectively-in the context of generalized (Sankoff) parsimony. Cladistic analysis recovers the traditional subdivision between those tinamous specialized for open areas (Nothurinae) and those inhabiting forested environments (Tinaminae) and support the monophyly of recognized genera. The present study demonstrates that morphological analysis yields highly congruent results when compared with previous molecular studies; thus, it provides morphological synapomorphies for clades that have been proposed by these molecular analyses. The placement of the fossil species within the open-area (Nothurinae) and the forest-dwelling (Tinaminae) tinamous is also consistent with the palaeoenvironmental conditions inferred from the associated flora and fauna.