Emergent Miocene: 23 - 5.3 mya
Features of the Miocene epoch 23 -5.3 mya:
5) Grasslands and savannas spread through N. America, while deserts develop later, in the Pliocene and Pleistocene epochs.
1) dated at 20-23 mya: M. Leakey discovers earliest hominoid fossil on Rusinga Island (in Lake Victoria, Kenya), in 1951: Proconsul heseloni
a) the earliest of apes;
b) retained some skeletal, monkey-like features of backbone, pelvis, and forelimbs;
c) quadruped (walked on all four limbs), not a brachiator ( tree-swinger)
4) dated at 6.5 mya: Fossil of Sahelanthropus tschadensis is the first hominin discovered.
2) dated at 17 mya: early apes traversed a land bridge (due to lowered sea-levels) into Eurasia:
a) developed thick tooth enamel, allowing diet of nuts and tough-coated seeds, not available to Proconsul;
b) apes diversified into at least 8 forms.
3) dated at 13 mya: 2 lineages of early apes -
a) Asia: Sivapithecus migrates to S.E. Asia, ancestor of orang-utans;
b) Europe: Dryopithecus migrates back to Africa, ancestor of African apes and