Schematic of different phylogenetic trees for the four gibbon genera.

The trees represented in box A to F have been proposed as the results of previous studies and can be compared with the maximum-likelihood tree found in this study (G). (A) cf. [2], [7], [8], (B) cf. [6], [11], [12], (C) cf. [9], [10], (D) cf. [3], (E) cf. [4], [5], (F) cf. [28].