50 years ago, evidence showed that an extinct human ancestor walked upright

Fossils show man walked 3 million years ago — Science News, February 16, 1974

Anthropologist D. Carl Johanson … has discovered a skull fragment, shin and thigh bones of a 3-million-year-old man in Ethiopia…. The bones belonged to an ape man (hominid) of the genus Australopithecus.… “We have absolute, concrete evidence that our ancestors walked on two legs over 3 million years ago,” the 30-year-old scientist told a news conference.

Update

Exactly when upright walking emerged in the evolutionary history of humans remains hotly debated. Fossil analyses suggest that several hominid species ambled around on two legs about 5 million to 7 million years ago. An upper leg bone of the oldest known, 7-million-year-old Sahelanthropus tchadensis, bears signs of upright walking including an inner projection near the hip joint, scientists reported in 2022 (SN: 9/24/22). But not all paleoanthropologists are convinced those features prove a two-legged gait. And some scientists think the bone belonged to an ape that may have walked upright at times.