-The discovery-
South of Nariokotome, north of Lomekwi River and west of Lake Turkana in Kenya, Richard Leakey and Alan Walker made an important discovery in paleoanthropology. It was 1985 and Leakey and Walker were searching for the remaining fossils of the previous year's bounty, Turkana Boy, a nearly complete skeleton of an African Homo erectus/Homo ergaster child. Their search was proving fruitless, only turning up hippopotamus bones, until Alan Walker chose to take a second look at one of the skulls. It was then that he came across the upper jaw and skull of something decidedly not a hippo. Something that looked like it could belong to a hominid.

The portions he found displayed characteristics unlike any seen before; the brain cavity was small and jaw showed large tooth roots. These things alone suggested that the theories formulated about human evolution might have to be altered somewhat. Then, two days after his find another member of the team, Pat Shipman, struck gold. Shipman discovered the dorsal ventral skull piece from the same specimen. Shockingly, it had the largest sagittal crest of any hominid fossil specimen ever found. The crest actually compounded with the nuchal crest, a feature commonly found in Australopithecus afarensis.

Walker set to work reconstructing the skull from the portions found, piecing it back together and using the parts found to estimate what the missing portions would look like. While the cranium was easy to formulate, the face was not a piece of cake. It was highly fragmented and had unique characteristics. Walker called the face "vintage A./P. boisei, large and dish shaped." The size of the skull in comparison was almost cartoonishly small, by far the smallest of all the hominid fossils at 410 cubic centimeters.

The skull was nicknamed the "Black Skull" for it's blue-black coloration caused by the manganese rich sediment. During the fossilization process the salts penetrated the bone causing a bronzing affect.


-Distinctly different-
Testing the sediment it was found in and carbon dating the bones showed that it was roughly 2.5 million years old, however Leakey and Walker were hesitant to name it. It had characteristics of both Australopithecus boisei and Australopithecus afarensis, and still other variations never seen before. The dating placed the fossil midway between afarensis and boisei hominids, suggesting an all new species.

One of the characteristics that show this skull isn't in the Homo lineage occurs in the teeth. The size of the posterior teeth increases as the anterior teeth decrease in the Black Skull, whereas in Homo hominids both the posterior and anterior teeth experience a decrease in size. This detail coupled with the australopithecine similarities proved that this was indeed a different species of hominid.

An offshoot of the Australopithecus afarensis line, the Black Skull shows that some australopithecines were successful in disbursing in a wide geographical area, even if they eventually went extinct. Dubbed Australopithecus aethiopicus, these hominids were robust and developed unique masticatory adaptations that allowed them to survive on vast amounts of low quality foods.



References
Antiquity of Man Black Skull, http://www.antiquityofman.com/black_skull.html
The Black Skull, http://faculty.vassar.edu/piketay/evolution/Black_Skull.html
Footstepts Through Time, http://www.abouthumanevolution.net/html/black_skull.htm

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