is the birthday of Mary Leakey, the English paleontologist and anthropologist who made ground-breaking discoveries about the origins of humans while working in East Africa with her husband, Louis Leakey. In 1959 she unearthed a 1.75-million-year-old jaw of an early hominid she called Zinjanthropus, now considered a species of Australopithecus. That discovery showed that hominids had appeared in Africa much earlier than previously thought. Her most important find came in 1978, when she discovered two trails of hominid footprints in 3.5-million-year-old volcanic ash--pushing back the date for the earliest evidence of upright posture for humans. In 1996, Leakey died in Nairobi at the age of 83.
[Source: McMurray, Emily, ed. Notable Twentieth Century Scientists. Gale Research Inc. ITP. 1995.]