Brain Size
Homo Sapien
Skulls
• Cranial capacities 700 cm3 to
1250 cm3
• Brain size closely linked with
overall body size
• H. erectus is larger-bodied
than early Homo sample but
relative brain size is about the
same
• Relative brain size of H.
erectus is considerably less
encephalized than later
members of genus Homo
1. Australopithecus afarensis
2. Australopithecus africanus
3. Homo habilis
4. Homo erectus
5. Homo Neandertalensis
Cranial Shape
• Thick cranial bone, large
browridges (supraorbital tori), and
projecting nuchal torus
• Braincase long and low, with little
forehead development
• Cranium wider at base, compared
with earlier and later species
• Sagittal keel, a small ridge from
front to back along the sagittal
suture, reflects bone buttressing
in a very robust skull, rather than
a specific function
Homo Erectus finds
Africa, Asia, Indonesia, Europe
Homo erectus from Africa
•
Homo erectus evolved first in Africa, supported by
evidence of:
1. Earlier hominins prior to the appearance of H.
erectus occurring in Africa.
2. 1.8 mya fossils at East Turkana, in Kenya, and
not long after at other sites in East Africa.
3. Though, 1.75 mya populations in southeastern
Europe; 1.6 mya populations in Indonesia,
suggesting quick migrations
TURKANA BOY
a.k.a. Nariokotome Skeleton WT 15000
• In 1984, Kamoya Kimeu
discovered a small piece of
skull on the west side of Lake
Turkana at the site known as
Nariokotome.
• The excavations produced
the most complete H. erectus
skeleton ever found
• Facial bones, a pelvis, and
most of the limb bones, ribs,
and vertebrae.
TURKANA BOY
Nariokotome Skeleton
• The Nariokotome
skeleton is dated to
about 1.6 mya.
• The skeleton is that of a
boy about 12 years of
age with an estimated
height of 5 feet 3
inches.
Olduvai Gorge
• Find by Louis Leakey in 1960,
includes well-preserved cranial
vault with small part of upper face.
• Dated at 1.4 mya, the cranial
capacity is the largest of all the
African H. erectus specimens.
• The browridge is the largest known
for any hominin, but the walls of
the braincase are thin.
– Similar to East African H.
erectus specimens; differs
from thick cranial bones in
Asian H. erectus.
Gona Evidence
• Ethiopia find dated to appx. 1.3 mya
• Female pelvis with very wide birth canal, indicating large-brained infants
in utero
• Perhaps newborn H. erectus with a brain that was comparable to typical
modern human baby
• Suggests, when compared with Nariokotome pelvis, considerable sexual
dimorphism in skeletal anatomy is linked to reproduction and body size
Daka Evidence
• Middle Awash of
Ethiopia find dated to
appx. 1 mya
• Complete cranium
more like Asian H.
erectus than most
earlier East African
remains discussed
• Discounts argument
that East African fossils
are different species
than Asian H. erectus
The Earliest African Emigrants
• Why they left is a mystery
• A greater range of physical variation in
specimens outside of Africa at about 1.8 mya
• Into Java, Indonesia by 1.6 mya
• Equates to less than 200,000 years to travel
from East Africa to Southeast Asia
The Dmanisi Hominins
•
•
•
The discovery of the Dmanisi materials in the Republic of Georgia began in the early 1990s.
The most informative specimens are four well-preserved crania, with one recently discovered
being almost complete.
The remains are the best-preserved hominins of this age found anywhere outside of Africa.
The Dmanisi Hominins
• The most complete specimen has
a less robust and thinner
browridge, a projecting lower
face, and a large upper canine.
• All three Dmanisi crania have
small cranial capacities.
• A number of stone tools, similar to
Olduwan industry from Africa,
have been recovered at Dmanisi.
• Remains from four individuals
allows comparisons with H.
erectus from other areas
Dmanisi Diagnostic Characteristics
• Estimated height ranging from ca 4 feet 9
inches to 5 feet 5 inches, smaller than full H.
erectus specimens from East Africa or Asia
• Body proportions, however, similar to H.
erectus (and H. sapiens) and different from
earlier hominins
Possibilities Raised by the Dmansi Discoveries
1. First hominins to leave Africa were small-bodied early form
of H. erectus, with smaller brains than later forms and
carrying a typical African Oldowan stone tool culture
2. These hominins had none of the adaptations hypothesized
to be essential to hominin migration: tall and relative large
brains
3. Perhaps two migrations out of Africa at the time: smallbrained, short-statured Dmanisi hominins and large, robust
body build of H. erectus populations of Java and China
Homo Erectus from Indonesia
• Six sites in eastern
Java, dating from 1.6
mya to 1 mya, during
the Early to Middle
Pleistocene.
• The Ngandong
individuals date from
27,000 ya.
– Homo erectus
Soloiensus (“Solo
man”) formerly
classified as Homo
Sapiens
Homo erectus from China
• 40 male and female
adults and children near
Beijing, at Zhoukoudian,
excavated beginning in
1920’s.
• 14 skullcaps, other
cranial pieces, more than
100 isolated teeth, and
scattering of postcranial
remains
• Formerly called “Peking
Man” or Homo erectus
Pekinensis
European specimens
• Atapuerca region in northern Spain,
1.2 mya
– partial jaw with few
teeth;closely resembles Dmanisi
fossils; simple flake tools and
animal bones
• Gran Dolina, dated to appx 850,000780,000 ya
• Assigning the fossils to a particular
species is problematic, based on the
fragmentary nature of the remains
• Spanish paleoanthropologists place
these hominins into a species called
Homo antecessor
Homo erectus Timeline