Figure 1. Model of evolution of primate mating systems showing posterior distribution of transition rates between states. A. Monogamy and polygyny. B. Monogamy, harem-polygyny and polygynandry. Thickness of arrows reflects proportion of time the transition rate is not zero. Z denotes a zero transition rate as a proportion of posterior probability distribution. A dashed line denotes a zero transition rate in the RJ derived model. Graphs show posterior probability distribution of each transition rate.