 Her husband and fellow scientist Louis Leakey initially classified the hominid as "Zinjanthropus boisei" and thought that it was an early ancestor of modern humans that lived approximately 2 million years ago.However, this contention was later withdrawn because of its robust australopithecine features and the discovery of "Homo habilis" soon thereafter.Mary and Louis Leakey had conducted excavations in Tanzania since the 1930s, though most such work was postponed due to the outbreak of World War II.