© AMNH / Denis Finnin

Homo ergaster diorama

Reconstructing a Skull

Although the skeleton nicknamed "Turkana Boy is one of the most complete ancient hominid skeletons ever discovered, parts of the skull were never found. Based on comparison with other fossils, experts have filled in the missing portions of the skull

Two's Company

The 1975 discovery of the nearly complete Homo ergaster skull overturned the once-popular idea that only one species of hominid could exist at a given time. Kenyan fossil hunter Bernard Ngeneo found the skull near Lake Turkana, not far from where others had unearthed a skull identified as Australopithecus boisei. Both skulls were buried in sediments dating back 1.9 million years.

Type Specimen: Homo ergaster

According to international convention, every new species must be represented by a type specimen. The type specimen is often, though not always, the first fossil of a species to be found, and it essentially sets the standard for that species. The lower jaw was discovered in 1971 near Lake Turkana. Only later, in 1975, did researchers designate it as the type specimen of Homo ergaster. 

© AMNH / Rod Mickens

Homo sp. cranium; East Turkana, Kenya

Lake Turkana Tools

Although the hominids that appeared on the scene around two million years ago had a build that resembled modern humans, the stone tools they made were still very simple. Like older hominid species, early Homo ergaster knocked flakes from a rock to create sharp edges for cutting and scraping.

Homo sp. cranium
 1.9 million years old
 East Turkana, Kenya
 Cast of KNM-ER 1813