HOMO ERECTUS

extinct species of early hominid that, while there is still considerable disagreement on the point, is thought to be the direct ancestor of modern Homo sapiens. H. erectus, a relatively recent creature in hominid evolution, flourished from the beginning of the Pleistocene epoch to sometime in the Middle Pleistocene, about 1,600,000 to 250,000 years ago. Fossil remains of H. erectus were first found in the 1890s, but, lacking a wide overview of how humans evolved, the discoverers of the first H. erectus fossils gave them a confusing variety of individual names that obscured the similarities and tended to exaggerate the differences between the various fossil finds. Now, by general agreement, these remains are classified as Homo erectus. Chronologically, H. erectus is preceded by Australopithecus, a more apelike hominid, and is succeeded by H. sapiens. H. habilis, whose remains have been recovered from sites between 2 million and 1.5 million years old, may be a transitional stage between Australopithecus and H. erectus. H. erectus appears to have ranged widely over the Earth. These fossils were first found at Trinil on the island of Java; other finds were near Peking, at Ternifine in Algeria, and at Olduvai Gorge and Koobi Fora in eastern Africa. Specimens from Europe were discovered at Bilzingsleben and Mauer (both in Germany), and Petralona (Greece), and in northwestern Africa at Sal, Sidi 'Abd ar-Rahman, and Rabat, all in Morocco. There are fossils that seem to represent subspecies of H. sapiens dating from the late Middle or early Late Pleistocene and found in Africa at Kabwe (Broken Hill), Elandsfontein, the Cave of Hearths, Lake Ndutu, Omo, and Bodo, and in Europe at Swanscombe, Steinheim, Biache, Ehringsdorf, La Chaise, and Vrtesszollos. It is among these that the line of distinction between H. erectus and H. sapiens becomes dim, for it seems that one species was grading imperceptibly into its successor. Most of the anatomical differences between H. erectus and H. sapiens concern the skulls and teeth. The limb bones of H. erectus that have been found so far have been similar to H. sapiens, leading to the inference that H. erectus was a creature of medium stature who walked upright. Skull fragments show that H. erectus had a smaller brain than modern humansless than 1,000 cubic cm (60 cubic inches) on the average, over a range from 750 to 1,225 cubic cm. The average cranial capacity for modern H. sapiens is 1,450 cubic cm, but the range is much greater1,000 to 2,000 cubic cm. H. erectus, however, had a larger brain than Australopithecus. The gap in brain size between the australopithecines and H. erectus, however, is filled by H. habilis, who, based on this evidence, is thought to be the immediate predecessor of H. erectus. The skulls of the H. erectus fossils show other characteristics of their physical appearance. The braincase is low, and the skull bones are thick. They have jutting brow ridges and a markedly thickened area of bone at the hind end of the skull called the occipital torus. The forehead recedes, and the nose, jaws, and palate are wide. The front teeth are larger even than Australopithecusan archaic trait that occurs in apes but in no other hominids. It is generally agreed, however, that the dentition is hominid and not apelike. These mixed traits are puzzling. Some paleoanthropologists see them as specialized features characteristic of neither H. sapiens nor the apes and question whether H. erectus evolved toward H. sapiens. According to these paleoanthropologists, H. erectus wandered off the main evolutionary line and could not have been an ancestor to modern humans. This appears to leave two possibilities. Either H. erectus, with his thick cranium and outsize dentition, was not on the direct evolutionary line from Australopithecus to H. sapiens, or H. erectus evolved specialized features from Australopithecus and then lost them again in the transition to H. sapiens. Other authorities judge these two choices to be an oversimplification of the problem. In any case, all anthropological evidence indicates that H. erectus was the first hominid to master fire and inhabit caves.