HOMO HABILIS

Comments: The skull known as KNM ER 1813 was discovered by Kamoya Kimeu in 1973 around the Lake Turkana region of Koobi Fora, Kenya. Its discovery sparked a debate over the primitive human genus Homo. Just one year earlier, KNM ER 1470 was found and presented as Homo habilis but differences between it and the newly discovered ER 1813 caused confusion. From the initial introduction of Homo habilis as a species in 1964, many scientists did not accept its validity, believing that all specimens should be assigned either to the genus Australopithecus or to Homo erectus. Today, H. habilis is widely accepted as a species.

Because of pressure during fossilization, the KNM ER 1813 skull is slightly distorted and skewed on its left side. ER 1813 has a cranial capacity of only 510 cc, which falls below the 600 cc cutoff that had been in place since the creation of the Homo habilis species name and it is not much larger than the average for Australopithecus. Despite its diminutive size, KNM ER 1813 was fully mature at the time of death based on its third molars which were fully erupted and showed evidence of wear. This skull can be compared and grouped with many of the accepted Homo habilis specimens from Olduvai Gorge such as OH-24. They share similar overall size, smaller orbits and the presence of sub-nasal prognathism which is the projection of the face below the nose. Some researchers believe the small ridge of bone crossing the skull from side to side on the lower back region may be the beginnings of the "transverse torus" of later Homo erectus.

In 1964, Louis Leakey, Phillip Tobias, and John Napier announced the new species Homo habilis, or "handy man". Homo habilis is so called because of the large quantity of PEBBLE TOOLS that have been found with its fossils. The average H. habilis brain was considerably larger than the average Australopithecus brain and its shape was also more humanlike. The bulge of Broca's area which is essential for speech, is visible in one H. habilis brain cast, indicating that Homo habilis may have been capable of basic speech.

Homo habilis was originally thought to be the ancestor to all later Homo. In a neat, linear progression, later species emerged resulting in what we call modern humans. This is now known not to be the case.