Whence Homo floresiensis ? - The Fossil Chronicles - page 173

ing that more than a thousand artifacts recovered at the site resemble
early African stone tools dated to about 2.6 million years ago as well as
the classic 1.9 million- to 1.6-million-year-old Oldowan tools that were
found in association with australopithecines and Homo habilis at Olduvai
Gorge . 60 The Dmanisi tools were made of local basalt and consist of
“rare choppers, chopping tools, a few scrapers, and numerous flakes.” 61
Significantly, despite its small stature and small brain (compared with
WT 15K's brain of nearly 900 cm 3 ), the Dmanisi youth had arms and legs
that were proportioned like those of WT 15K and living people, rather
than like australopithecines and the OH 62 partial skeleton attributed to
Homo habilis (but believed by some, including me, to have actually been
an australopithecine). The other Dmanisi fossils suggest that, like WT
15K, these hominins walked with a spring in their step (good arches)
and had humanlike nongrasping big toes that were lined up alongside
the other toes. The Dmanisi hominins also shared WT 15K's primitive
(more australopithecine-like) upper-arm anatomy . 62
A relatively long leg (in the Dmanisi youth of nearly 1.8 million years
ago) may, thus, have preceded a relatively enlarged brain (in WT 15K of
1.6 million years ago) during the evolution of early Homo. Or perhaps not.
An incredible amount of variation exists in the fossil record of between
1.8 million and 1.5 million years ago (some of which may have been due
to differences in the sizes of males and females), which must be taken
into account when interpreting the relatively small cranial capacities
observed at Dmanisi. This requirement is underscored by the recent
discovery of a 1.55-million-year-old Homo erectus skull (KNM-ER 42700)
from Koobi Fora, Kenya, that surprisingly has some of the more derived
(advanced) classic Asian Homo erectus features. 63 The skull's cranial capac-
ity of 691 cm 3 is not that much larger than the Dmanisi youth's. It is also
worth noting that cranial capacities varying from 790 to 2,350 cm 3 have
been reported for normally functioning modern humans ! 64 We have no
reason to assume, without justification, that cranial capacity was not
also highly variable for prehistoric hominins—especially if the males
were considerably larger-bodied than the females.