Historical relationships of Amazonian areas of endemism based on raw distributions of parrots (Psittacidae)

During the last 30 years, various hypotheses have been proposed to explain the processes and models of diversification in the Neotropical biota. Here We present another hypothesis using Parsimony Analysis of Endemicity (PAE) applied to raw distributions of parrots in nine Amazonian areas of endemism. This method is analogous to cladistic methods and it groups areas by their shared taxa according to the most parsimonious solution. The single most parsimonious tree obtained indicates a subdivision of the Amazonian biota into two main regions which represent Upper and Lower Amazonia. This result is discussed in the light of previous hypotheses obtained by other authors with the same method using Primates, Passerine birds, lizards and anurans. Likewise, comparisons with previous hypotheses on lineages of birds and mammals obtained with other cladistic biogeographic methods are given. The present hyothesis is congruent with those of primates and lizards.