New York, Nov 24 (IANS): Google Doodle on Tuesday celebrated the 41st anniversary of the discovery of the world's most famous early human ancestor -- the 3.2 million-year-old ape 'Lucy'.

'Lucy' was the first Australopithecus afarensis skeleton ever found, though her remains are only about 40 percent.

Australopithecus afarensis is an extinct hominid that lived between 3.9 and 2.9 million years ago.

Exactly 41 years ago, the humanity came to know about the oldest known example of a bipedal primate and a crucial stepping stone between apes and homo sapiens.

Unearthed in Ethiopia by palaeontologist Donald C Johanson, Lucy became the oldest known example of a bipedal primate.

Lucy had many similarities with chimpanzees, the skeleton showed that she primarily walked upright.

Bipedalism is seen as one of the key distinctions between Homo sapiens and chimpanzees.

According to National Geographic, with a mixture of ape and human features -- including long dangling arms but pelvic, spine, foot, and leg bones suited to walking upright -- slender Lucy stood three-and-a-half feet tall.

Inspired by repeated playings of "Lucy in the sky with diamonds" at a celebratory party on the day the specimen was found, researchers named it 'Lucy'.

Lucy's size gives her away as a female. Later fossil discoveries established that A. afarensis males were quite a bit larger than females.

A number of factors point to Lucy being fully grown.

For one thing, her wisdom teeth, which were very human-like, were exposed and appear to have been in use for a while before her death.

"In addition, the sections of her skull -- separated in children -- had grown together," the National Geographic report added.

Lucy's bones are kept in a museum in Ethiopia.