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acterized by taller stature, long legs, and wide pelvis (although, relative to stature, not as wide as in the australopithecines). This change would have occurred in the species known either as Homo ergaster, a term that applies exclusively to African fossils, or H. erectus, a term that includes both the African specimens and Asian fossils from Java, where the species was defined, and Zhoukoudian (and some other sites) in China. The juvenile skeleton from Lake Turkana (KNM-WT 15000) dates to 1.5–1.6 mya and belongs to what we might call this “large hominid” to differentiate it from other earlier and contemporaneous specimens. There appears to have been a long period of coexistence of H. habilis and H. ergaster in East Africa, which would indicate not a lineal (anagenetic) evolutionary pattern, but a branching (cladogenetic) pattern of evolution. Some authors further recognize a third sympatric and synchronic species of Homo: Homo rudolfensis.

The tall and wide morphotype first seen in H. ergaster/erectus was maintained until the end of the Middle Pleistocene, when two new morphotypes appear. One, seen in modern humans, shows a narrower body cylinder and the other, seen in Neanderthals, shows a shortening of the distal segments of the extremities. The earliest (well-dated) modern human fossils are from Ethiopia and are represented by the skeleton of Omo I (~196 kya) (Pearson et al., 2008) and the crania from Herto (~150–160 kya) (White et al., 2003).

From the point of view of the postcranial skeleton, then, there would be only four morphotypes within the genus Homo, although the fossils from Dmanisi (Lordkipanidze et al., 2005, 2007; Rightmire et al., 2006) in Georgia (~1.75 mya) might represent an intermediate form between the primitive, australopithecine, morphotype of H. habilis and the tall and wide morphotype of H. ergaster/erectus. The skull of Homo georgicus is morphologically intermediate between H. habilis and H. ergaster or, alternatively, is a primitive form of the latter, which some authors, in turn, consider to be a primitive grade within H. erectus.

In reality, however, postcranial remains are abundant only at the Middle Pleistocene site of the Sima de los Huesos in the Sierra de Atapuerca, dated to at least 530 kya. Nevertheless, the isolated fossils from other sites such as the East African pelvises KNM-ER 3228 (perhaps older than the Turkana Boy) and OH 28 (<1.0 mya) as well as the Middle Pleistocene skeleton from Jinniushan in China (Rosenberg et al., 2006) do not differ from those at the Sima de los Huesos.

This overview has necessarily glossed over numerous details. Although living modern human populations are considered “tall hominids” compared with the early hominids, a wide variation in stature exists across the globe today. In Africa alone, there are modern human populations with average male stature <150 cm and others with averages ~180 cm.



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