Biology Reference
In-Depth Information
we have seen, short, bipedal australopithecines with apelike body pro-
portions and a habit of climbing in trees lived in Africa between at
least 3.6 million (Kadanuumuu) and 1.8 million years ago (OH 62), and
confirms that a species of early African
Homo
had evolved bigger brains,
humanlike limb proportions, and habitual bipedalism by 1.6 million
ent body builds and distinctive types of bipedalism are highly likely to
A basic tenet of paleoanthropology is that australopithecines became
extinct without ever having left Africa. Instead, long-legged early
Homo,
such as the Nariokotome lad, was supposed to have been the hominin
who first walked out of Africa to colonize other parts of the world.
dmanisi: a surprise from eurasia
The classic assumption about early
Homo
first colonizing the world is
now being questioned because of the discovery of perplexing fossils
dated at 1.77 million years ago from outside Africa. As noted, the speci-
mens were unearthed at the site of Dmanisi, in the Republic of Georgia,
example, four Dmanisi individuals had cranial capacities that ranged
between 600 cm
3
and 780 cm
3
. These volumes are larger than those
for any known australopithecine but smaller than the approximately
900 cm
3
volume of WT 15K and some of the other African skulls that
have been attributed to early
Homo.
The Dmanisi skulls possess an unusual mixture of other features.
Constriction behind the eye sockets, a smallish face beneath a mod-
erately thick brow ridge, and a rounded back end of the cranium are
primitive features that the Dmanisi fossils have in common with the
crania are more suggestive of African (and, to a lesser extent, Asian)
