But fossilized human prints are extremely rare. In Africa only three footprint sites were discovered. One, found in Laetoli, Tanzania, is 3.7 million years old and represents the earliest direct evidence of hominin bipedalism. The prints were made by Australopithecus afarensis, an hominin that lived between 3.9 and 2.9 million years ago and whose best known specimen is the famous Lucy.
Other two sites in Kenya, at Ileret and Koobi Fora, are dated to 1.5-1.4 million years ago and display prints of different homind species.
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"It is very likely the area around Ileret and Koobi Fora was populated by H. erectus, although also Homo habilis and perhaps members of the Paranthropus genus lived there. On the contrary, the area where our footprints were unearthed was inhabited only by H. erectus, thus the importance of the finding," Coppa said.
He noted that until now no footprint could have been traced back to 800,000 years ago, during the transition between early and mid-Pleistocene.