Commander William T. Riker mutated into an australopithecine after contracting Barclay's Protomorphosis Syndrome in 2370. (TNG: "Genesis" ) According to the Star Trek Encyclopedia (4th ed., vol. 1, p. 52) , Australopithecine lifeforms – which included the species A. afarensis, A. robustus, and A. boisei – inhabited Earth 4 to 5 million years ago.