Neighbor-joining (Saitou and Nei 1987) phylogram of 101 mitochondrial coding region sequences using the Kimura two-parameter model for nucleotide substitution. The tree is rooted with a single chimpanzee sequence. Branches of less than 50% bootstrap support (1000 replicates) are collapsed. Bootstrap values are shown on the nodes. Numbering refers to tree structures discussed in the text. NG, New Guinea.