3.29-3.12 million years ago
AL (Afar locality)-288-1 is better known as Lucy: probably the most famous individual hominin fossil. Her skeleton is particularly complete, and demonstrated the existence of a previously unknown species, Australopithecus afarensis.
When she was discovered in 1974, she pushed back the hominin fossil record by over a million years. A. afarensis looked like a plausible ancestor to all the later hominins. (Things have gotten complicated since then.) “The first family” (AL 333) was discovered just a year later: bones of at least 13 individuals, a mixture of adults and juveniles, maybe all victims of a flash flood. This helped to fill in knowledge of individual variation among A. afarensis. And subsequent findings have documented the species over a million year span from 4-3 million years ago. At the same time, later discoveries have also suggested that there were likely multiple hominid species around in Lucy’s day.
Also: Her pelvis is basin-shaped, and she stood with her legs under her body, not rocking from side to side. All this is like a human, not a chimpanzee. So she was certainly bipedal, but there are arguments about just how bipedal. The initial view was that she was an efficient walker (although not much of a runner: that comes later). But another school of thought points out that she’s got very long arms, and curved finger and toe bones, suggesting she spent a lot of time in trees. Her long toes might have made her an inefficient biped (a view derided by members of the Lucy-the-proficient-walker school as the clown shoe hypothesis).
Lucy got her name from this song, played on a camp loudspeaker the day she was discovered. John Lennon, who wrote the lyrics, always denied that Lucy in the Sky with Diamonds, in spite of the initials, had anything to do with LSD. He said that it was based on picture that his son Julian (then four years old) made in school, with some Lewis Carroll thrown in.
‘I could tell you my adventures—beginning from this morning,’ said Alice a little timidly; ‘but it’s no use going back to yesterday, because I was a different person then.’
Alice in Wonderland Lewis Carroll