Homo erectus - Leakey Ancestors

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The Skull Replica
This half scale model is based on a skull cap discovered in 1891, Trinil 2 ("Java Man") and a composite skull and mandible discovered between 1928-37 ("Peking Man"). The skull is very different from discoveries made later in Africa, frequently called Homo ergaster.

At the time of its discovery, the skull was the most complete known for Homo erectus. Previously none of the specimens had a face articulated with the cranium. The mandible is also unusually complete, although it has been partially reconstructed in the model. It was not until the discovery of the 'Nariokotome Boy' that an associated skull and mandible of this species was found.

Overview
Homo erectus was first recognised in Java, when Eugene Dubois discovered a tooth, skullcap and femur in 1892. He named his discovery Pithecanthropus erectus believing that the specimens represented a human ancestor that was too primitive to be included in the genus Homo. Pithecanthropus means 'ape-man', and the species name erectus reflects the very human-like femur which told Dubois that this early human ancestor walked upright. It was not until 1960 that the name Pithecanthropus was formerly revised to Homo. Subsequent to Dubois' discovery, Davidson Black worked in the Chinese site of Zhoukoudian and in 1929 discovered a skull cap more complete than Dubois' but very similar in shape. This was followed by further specimens a swell as stone tools.

The erectus skull is quite distinctive. It has a much larger braincase than the australopithecines - almost twice as large as that of Australopithecus boisei, but smaller than Homo sapiens. The average cranial capacity for Homo erectus is ~1000cc. Homo erectus had a relatively small face, small teeth and weak jaw muscles. In many respects the skull is closely similar to Homo sapiens, but it lacks a forehead and has prominent ridges (supraorbital tori) above the eye sockets. Another Homo erectus cranial character is the 'occipital bun', the distinct bun-shaped protrusion at the back of the skull. The mandible is more lightly built than that of the australopithecines, but it lacks the chin that is typical of Homo sapiens.

Homo erectus first appears in Europe and Asia almost immediately after it is first found in Africa. The earliest Homo ergaster in Africa is the skull KNM-ER 3733, dated at almost 1.8 million years. New dates suggest that Homo erectus reached Java sometime between 1.8 and 1.6 million years ago, and a Homo erectus mandible from Dmanisi in the Georgian Republic is believed to be of a similar age. It seems that Homo ergaster moved out of Africa almost as soon as it arose.

Where it is found ?
Homo erectus was the first human ancestor to move out of Africa into Europe and Asia. This species is known from China, and Javaand in Africa as Homo ergaster in Eritrea, Ethiopia, Kenya, Tanzania and South Africa.

The Asian sites are on Java in Trinil, and Sangiran (both in Indonesia). The largest number of H. erectus finds in one place is at Zhoukoudian Cave in China.

Classification
Eugene Dubois believed that his teeth, skull cap and femur were so different from Homo sapiens that he named a new genus, Pithecanthropus aswell as a new species erectus. Later it was realised that the similarities with Homo sapiens were close enough that Pithecanthropus erectus should be included within the genus Homo, although the differences from H. sapiens were large enough that the species name "erectus" was justified.

There are also differences in opinion as to what the correct name for the African specimens should be. When Homo erectus was first recognised in Africa, several researchers suggested that this was not the same species as that found in Java and China. In due course a new name, Homo ergaster was given to the African Homo erectus and the mandible KNM-ER 992 was designated the type specimen. Additional specimens have not resolved this issue and the difference of opinion remains. We are using H. ergaster for the African material to differentiate it from the Asian specimens.

The classification of life is called taxonomy. The following shows the taxonomic sequence for Homo erectus:

Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata
Class Mammalia
Order Primates
Superfamily Hominoidea
Family Hominidae
Subfamily Homininae
Genus Homo
Species erectus

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