"Little Foot" (Stw 573) is the nickname given to a nearly complete Australopithecus fossil skeleton found in 1994 in the cave system of Sterkfontein, South Africa. The skeleton was 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 3.67 million years old, and its taxonomic placement is likewise disputed.
Discovery
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 Clarke. In 1994 while searching through museum boxes labelled 'Cercopithecoids' containing fossil fragments, Ronald 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. In the following months, Clarke and his two assistants with the help of a hammer and small chisel uncovered further foot bones. Stephen Motsumi discovered the first remains of the upper body, an upper arm bone on 11 September 1998, and eventually the head of the individual was seen as well. It was a skull connected with the lower jaw, which was facing up. These were announced to the press in 1998, resulting in considerable media attention around the world. A year later, in July and August 1999, a left forearm as well as the corresponding left hand were discovered and partly uncovered. These were again in anatomically correct arrangement. Subsequent work has uncovered a relatively complete skeleton, including parts of the pelvis, ribs and vertebrae, a complete humerus and most of the lower limb bones. At the time, it was recognized that it was likely to be far more complete than the famous Australopithecus afarensis skeleton, "Lucy", from the site of Hadar, Ethiopia. Clarke reported this discovery six months later and explained that all previous analyses indicated that the fossil's body was apparently complete and was possibly slightly moved by ground movements and also not damaged by predators. It took Clarke and his team two full decades to fully extricate, clean, and analyze the specimen, work that was finally completed in 2017.
Characteristics StW 573 (Little Foot) is a nearly complete case of an Australopithecus female specimen, including the skull, that provides plenty of information on this once obscure species that helps advance perspective on them. In the discovery of the cast, there was evidence of dental use where it shows to be prominent. Resemblances can be drawn to other cases found in South Africa, such as that of Australopithecus afarensis. The specimen is a female, 1.2-1.3 meters tall, whose lower limbs are longer than its upper limbs. Its hips are modern and capable of transmitting great force from its legs, and its hands are very large. Her body suggests a bipedal gait and, at the same time, that she had a great ability to climb trees. Morphological characteristics of StW 573's fossil are the complete limb lengths that demonstrate that StW 573 stood roughly to the height of 4 feet and that it exhibited forms of bipedalism due to the length of its legs. Although, StW 573 also prominently displays many features that other apes present such as an S-shaped curve in its collarbone along with a ventral bar. Other fragments of the cast such as the pectoral girdle and the high ridge of StW 573's shoulder blades suggest that it had a strong upper body to support its weight while it hung from branches and climbed trees. Overall this cast shows characteristics found in both human and other primates as it exhibits signs of walking upright, early bipedalism, and locomotion through the trees.
… excerpt ends here. Continue reading the full article.
