Little Foot

"Little Foot" (Stw 573) is the nickname given to a nearly complete Australopithecus fossil skeleton found in 1994–1998 in the cave system of Sterkfontein, South Africa.

Originally nicknamed "little foot" in 1995 when four ankle bones in a museum collection were sufficient to ascertain that the individual had been able to walk upright, the remainder of the skeleton was, subsequently, located in the cave from which the ankle bones had been collected.

Because the bones were completely embedded in concrete-like rock, their extremely difficult and tedious extraction took around 15 years. The bones proved to be the most complete skeleton of the early hominin lineage leading to humans, with 90% of the body being recovered.

Dating of the specimen has proved controversial, with estimates ranging from 2.2 to 3.5 million years old, and its taxonomic placement is likewise disputed.

Four ankle bones of this specimen were collected in 1980 but were unidentified among numerous other mammal bones. Only after 1992, on initiative by Phillip Tobias, a large rock was blown up in the cave that contained an unusual accumulation of fossils. The fossils recovered were taken from the cave and scrutinized thoroughly by paleoanthropologist Ronald J. Clarke.

In 1994 while searching through museum boxes labelled 'Cercopithecoids' containing fossil fragments, Ronald J. Clarke identified several that were unmistakably hominin. He spotted four left foot bones (the talus, navicular, medial cuneiform and first metatarsal) that were most likely from the same individual. These fragments came from the Silberberg Grotto, a large cavern within the Sterkfontein cave system. They were described as belonging to the genus Australopithecus, and catalogued as Stw 573.

Due to the diminutive nature of the bones, they were dubbed "Little Foot". Clarke found further foot bones from the same individual in separate bags in 1997, including a right fragment of the distal tibia that had been clearly sheared off from the rest of the bone. Early in 1997 two fossil preparators and assistants of Clarke, Stephen Motsumi and Nkwane Molefe, were sent to the Silberberg Grotto to try to find the matching piece of tibia from which the museum specimen had been broken.

Amazingly, within two days, they found the remaining part of the bone protruding from the rock in the lower part of the grotto. Though only the bones of both legs were visible, because they were in anatomically correct arrangement the team speculated that it could be a complete skeleton that was embedded with the face downward in the limestone.