|
Homo erectus is a major figure in our past. Fossils identified as
Homo erectus span most of the 1.9 million year Pleistocene era, a
period which includes the transition to larger-brained hominids, a basic
evolution of tool manufacture and use, and the first widespread movement
and adaptations of early human populations to distinct environments. Homo
erectus ranged further than any other hominid before Homo sapiens,
from Africa to Indonesia, China, Eurasia, and Western Europe – and probably,
at some intermediate points, back to Africa (fig.1).
 While the
long timespan, regional variability, and far-flung migrations of Homo
erectus are generally agreed upon, interpretations of the role of Homo
erectus in human evolution are more polarized, and tend to fall into
either “Replacement” or “Continuity” theories
(see glossary). Fig.1: Distribution of Homo erectus sites. Briefly,
Continuity (or Multiregionalist) theories regard Homo erectus as a
long-term, coherent species evolving over time into Homo sapiens. Replacement theories, on the other hand, hold that Homo erectus split
off from the nearly identical African Homo ergaster (considered the
direct ancestor of modern humans), and evolved into one or more separate
Asian species, going extinct without contributing to the modern human gene
pool. Based on MtDNA and Y-chromosome evidence, all modern humans descended
from a group of early Homo sapiens migrating from Africa after 200,000
years ago (Cann et al. 1987; Tattersall 1999, 2000).
Accumulated fossil and site evidence increasingly shows a remarkable adaptability
of Homo erectus populations to a wide range of environments during
their Pleistocene migrations. The behaviors that evolved during the long
span of Homo erectus (i.e., fully bipedal migrations, tool-making,
scavenging, hunting) are essentially the earliest human behaviors. This
introduction provides the reader with a brief historical background of findings
on Homo erectus.
Java Man and the concept of “erectus”:
Discovery of the first Homo erectus specimen in southeast
Asia was directly inspired by the 19th century “missing link” concept
of a bipedal “ape-man” who combined traits of today’s humans
and apes (see The
Discovery of Java Man in 1891). Both Charles Darwin and his
disciple Ernst Haeckel believed that upright posture and bipedalism were
direct precursors to tool making, by freeing the hands. Few if any Victorian
evolutionists, however, could have guessed that a gap of at least 3.5 million
years separated the first bipedalism, now known from the Late Miocene (Brunet
et al. 2002), from the first stone tools at 2.5 mya. Given today’s knowledge
that both apes and humans have evolved for 6-7 million years along different
paths from a common ancestor, the notion of Pithecanthropus as a hybrid
“ape-man” now appears fancifully naive or misguided. Yet the criteria
of erect posture or bipedalism remains the most important morphological trait
separating fossil hominids from apes. Bipedal locomotion or walking at first
supplemented tree climbing. Its evolutionary advantage most likely concerned
energy conservation in travelling (see The paleobiology of Homo erectus
and early hominid dispersal, by Susan Cachel). Gradually, by the time
of Homo erectus at ca. 1.8 mya, the human anatomy of long legs, tall
stature, and full bipedalism had evolved (Wood and Collard 1999).
When Dubois began his fieldwork in the late 1880s, only Neanderthals had
been identified as fossil hominids. Neanderthal remains from Germany and
Belgium, in terms of skeletal and cranial form, appeared robust but basically
modern (Huxley 1863). The quest to find a much earlier, more ape-like human
ancestor was a revolutionary step initiated by Dubois.
Revelations at Trinil: Indonesia
(then a Dutch colony) was still only tentatively known to contain Pliocene
and Pleistocene fossil beds, comparable to better documented zones in the
Siwalik Hills of Pakistan. Discovery in 1878 of an extinct Pleistocene chimpanzee
called Anthropithecus (“man-ape”) in the Siwalik beds helped
convince Dubois of southern Asia’s potential for “missing
link”evidence, as did the unique presence of the orangutan in Indonesia.
Pleistocene fossil beds along the Solo River and Kendig Hills in east-central
Java (named the Trinil or Kendig zone by Dubois) soon revealed faunal
correspondences with the Siwalik Hills, including rhinocerous, hippopotami,
a primitive elephant Stegadon, buffalo, deer, hyenas, and large felines.
In 1891, the Trinil beds produced a molar resembling Anthropithecus,
and then the hominid calvaria (skullcap) now called Trinil 2. The human left
femur (thighbone) found in 1892 was at first grouped with both as a kind
of advanced, bipedal chimpanzee named Anthropithecus erectus.
The Trinil 2 calvaria shows a low, sloping profile with a pinched-in, postorbital
constriction contrasting to the domelike form of the modern human skull.
Thick walls and heavy brow ridges also appeared apelike. Further study of
the skullcap by Dubois, however, with removal of the rock matrix in its cavity
revealed a much larger cranial capacity (900 cc), twice that of a chimp (ca.
450 cc). In a tribute to Haeckel, Dubois (1894) renamed the fossil
Pithecanthropus erectus, “erect ape-man,” a taxon to be
eventually (after discovery of the australopithecines in the 1920s-40s) replaced
by Homo erectus.
Further discoveries in Java: Two
decades after the Trinil 2 discovery, 1909-10 German excavations led by Margarete
Selenka across the Solo River from Trinil recovered Pleistocene fauna of
a narrower and mainly later range than those found by Dubois. While the
expedition found no hominid remains, it helped refine the Pleistocene
biostratigraphy of Java.
 Discovery
of the next fossil hominids in Java came in the early 1930s at Ngandong,
on an upper terrace of the Solo River only ten km from Trinil (fig.2). In
1931-1933 the Dutch Geological Survey under W. F. F. Oppennoorth excavated
rich Upper Pleistocene fossil deposits some 20 -24 m above the current level
of the Solo. Besides thousands of animal fossils (extinct buffalo, wild oxen,
Stegodon, pigs, tigers, etc.), the project recovered 12 hominid calvaria,
the largest sample from a single Javan site. Fig.2: Map of major Homo erectus sites in east-central Java
. The Ngandong remains, named
Homo soloensis by Oppennoorth (1932), represent a much-debated group
of Upper Pleistocene hominids. They had significantly larger cranial capacities
than earlier Javan Homo erectus, averaging 1210 cc compared to 883
cc (Jacob 1981). Massive brow ridges (fig.4) and thick cranial bones,
however, make “Solo Man” (dated ca. 200,000-25,000 BP) appear still
closely linked to Homo erectus.
Soon afterwards, in the mid-to-late1930s, paleontologist Ralph von Koenigswald
identified an important series of Lower and Middle Pleistocene Homo erectus
fossils collected by Javan farmers. Originally working with the Dutch Geological
Survey to classify fossil fauna, von Koenigswald obtained funding from the
Carnegie Institute of Washington DC for early hominid site exploration. In
the course of these 1930s projects, detailed geological maps were made in
Java (Shipman 2001; Huffman 2001).
At Sangiran, one of several large volcanic domes in east-central Java (which
ca. 1.5 mya formed a lake shore and riverine zone), von Koenigswald found
a Homo erectus mandible (1934); a skullcap called Sangiran 2, similar to
Trinil 2 but with a smaller cranial capacity of 815 cc (1937); and several
early Homo erectus skulls and mandibles with massive teeth (1938-9). One,
Sangiran 6, was at first classed as Paranthropus (or
Australopithecus) robustus. Another, Sangiran 4, has an
australopithecine-like diastema or gap between the upper canines and incisors.
Both are now considered to predate 1.5 mya.
An even earlier Homo erectus fossil of a child’s skull was recovered
by von Koenigswald in 1936 in the east Javan village of Perning near Mojokerto,
180 km east of Sangiran on the Brantus River. Now dated as early as
1.8 mya, the Perning skull came from a layer representing an ancient marine
deltaic setting. The fossils from Sangiran and Mojokerto demonstrate that
initial hominid migrations to southeast Asia came into a diverse range of
local environments.
Von Koenigswald took a number of Javan Homo erectus fossils to China in 1939
to compare with the Zhoukoudian hominid remains being studied by Franz
Weidenreich. Similarities seen by von Koenigswald and Weidenreich (1939)
eventually led to combined use of the Homo erectus taxon for both “Java
Man” and “Peking Man” (Mayr 1950).
During World War II, von Koenigswald managed to safeguard many of the Javan
fossils even though he was imprisoned by the Japanese from 1942-5. From the
1960s-80s, Tekeu Jacob directed numerous paleoanthropological projects in
Java, including excavations at Ngandong, Sambungmachan, and Sangiran revealing
several more Homo erectus and H. soloensis skulls (Jacob 1973, 1981). Since
the 1990s, work by international teams has progressed at a number of sites
including Mojokerto, Ngandong, and Sangiran Dome. Especially interesting
finds are Oldowan stone tools and faunal remains with butchery marks recovered
in the Bapang Formation in the Ngebung Hills (Semah et al. 1992).
Dating the Java sites: Before the
advent of potassium-based geochronology, the dating of fossil deposits in
Java was done by biostratigraphy, associating mammalian taxa with geological
layers. In 1969, geochronologist Garniss Curtis first applied potassium-argon
dating to a volcanic rock from the Mojokerto site, producing a date of 1.9
mya (Swisher et al. 2000). This was basically upheld over 20 years later
by more accurate Ar/Ar dates from 1.81-1.6 mya on pumice from the Pucangan
(Sangiran) Formation (Swisher et al. 1994). An independent series of dates
obtained for the overlying Kabuh (Bapang) Formation in central Java shows
a group of five Homo erectus fossils predating 1.51 mya (Larick et al. 2001;
Larick et al. 2004).
These early
dates remain controversial. If the oldest dates are accurate, correlations
with paleomagnetic stratigraphy from the Rift Valley of Africa would show
the arrival of hominids in Java as early as the Olduvai subchron (1.98-1.79
mya). Significantly, such early dates suggest the African emergence of Homo
and the initial dispersal to subtropical Asia may be directly linked. Conditions
favoring this  initial migration center on the geologically active Tethys
Corridor, a tectonic zone along the south edge of the European continental
plate. Environmental change created new subsistence niches at the start of
the Pleistocene, while lowered sea-levels due to glaciation exposed the Sunda
shelf, over which hominids could walk to southeast Asia.
Fig.3: The Sangiran 17 skull, dated at about 1.15 mya (photo:
Athena Review, from cast at AMNH).
Based on this recent dating, the earliest Homo erectus groups settled in
Java by 1.8-1.6 mya around coastal deltaic swamps and lakes at the south
end of the Sunda shelf, associated with the Sangiran formation and the Ci
Saat fauna (including the large carnivore Panthera and bovids such as deer
and hippopotami). Homo erectus fossils from this oldest level include the
primitive-looking Sangiran 4 found by von Koenigswald, as well as four other
individuals (Sangiran 27, 31, 41, and 57) found since 1978. At about 1.5
mya the Sangiran levels were superimposed by river and lake sediments of
the Kabuh Formation with associated Trinil Fauna (Dubois’ original Trinil
zone). Homo erectus finds include the relatively complete Sangiran 17 cranium
(fig. 3) found in 1969; the Sangiran 50 cranium and maxilla found in 1993
at Tanjung (see Larick et al.2004); and the Sangiran 2 skullcap of von
Koenigswald, all three dated at 1.25-1.0 mya, slightly earlier than the Trinil
2 calotte.
After 800,000 BP, fossil evidence ceases at the Sangiran Dome. Around this
time Homo erectus may have rafted across 25 km of ocean to the island
of Flores, east of Bali, where Oldowan tools have been found (Morwood et
al. 1998). More recent finds by Morwood and colleagues on Flores show that
very late, small Homo erectus-like hominids named
Homo floresiensis
still lived there from 95,000-13,000 BP, overlapping the time frame of "Solo
Man," and even living into the period of early animal and plant domestication
by modern humans in the Near East.
After a hiatus
of about 600,000 years after Trinil, the Homo soloensis remains found
in the Upper Pleistocene Notopuro and Ngandong Formations represent a much
more recent fossil hominid group from Java (fig.4). These problematic fossils
are disputed on grounds of their developmental ages, as well as overall taxonomy
and chronology (Antón 1999). Prior to the advent of absolute dates,
both Oppennoorth and von Koenigwald thought “Solo Man” could have
been related to the nearly contemporary Neanderthals, while Weidenreich (1945)
considered them an intermediate stage between Homo erectus and  Australian
aborigines. This latter view is continued today by some multiregionalists,
who see similarities in six of the Ngandong crania with a 15,000 year old,
anatomically modern human from Willandra Lakes, Australia (Wolpoff and Thorne
1991; Wolpoff et al. 2001).
Fig.4: Late Pleistocene Solo 6 skull from Ngandong, Java (photo:
Athena Review, from cast at AMNH).
Uranium-series and electron spin resonance (ESR) dates of 53-27,000 BP have
been obtained on bovid teeth from the same Ngandang deposit producing the
Homo soloensis skulls (Swisher et al.1997). These dates plus anatomical
evidence provide grounds to identify the Ngandong fossils as part of a very
late Homo erectus population contemporary with (and a separate species
from) Homo sapiens (Antón 2002). The Ngandong fossils remain
an important enigma, partly contemporaneous with both the newly found
Homo floresiensis
of the Indonesian island Flores, and the relatively large-brained fossil
skulls from Dali and Mapa in China, representing late Asiatic descendants
of Homo erectus.
Homo erectus in China: In the 1920s
the famous “Dragon Bone Hill” (Longgushan) quarry site at
Zhoukoudian yielded hominid fossils identified by Davidson Black as Sinanthropus
pekinensis, or “Peking Man”. The Longgushan limestone deposits,
originally mined for fossils called “dragon bones,” which were
ground up and sold by druggists as aphrodisiacs, eventually provided the
largest known sample of Homo erectus fossils. By 1937, when work halted
at Zhoukoudian due to Chinese civil war, excavations under W.C. Pei, Lanpo
Jia, and colleagues such as Teilhard de Chardin had produced six skullcaps,
eleven mandibles, a mixed assortment of facial bones, and about 150 teeth.
This sample, while notably lacking in long bones and extremities (see below),
represented over 40 individuals of both sexes and different ages, with cranial
capacities from 915-1225 cc
(Boaz and Ciochon 2004; see
book review by Dong Wei).
After Black
died suddenly in 1934, Franz Weidenreich, already familiar with some of the
Pithecanthropus finds from Java, took over the anatomical work in
1935 and eventually completed a detailed analysis of the Zhoukoudian hominids
(1943).  Recognizing many similarities with the Java fossil hominids after
consultations with von Koenigswald, Weidenreich nevertheless retained in
his publications the original, regionally distinct taxa of Sinanthropus
pekinensis and Pithecanthropus erectus. He supported, however,
combining both as Homo erectus as part of a single, evolving Homo
lineage (Mayr 1950).
Fig.5: Homo erectus skull from Zhoukoudian, China (photo:
Athena Review, cast at AMNH).
A mean cranial capacity of about 1050 cc. in the Zhoukoudian skulls shows
larger brain size compared to the somewhat earlier Java H. erectus,
but many basic similarities. The low-slung, thick-walled skulls from both
Java and China are widest at their base, and have large brow ridges, a sagittal
keel on top, and a protruding ridge at the rear (occipital) bone (fig. 5;
based on the reconstruction by Tattersall and Sawyer 1996). Homo erectus
also lacked a chin, and the jaws and teeth are significantly more robust
than in modern humans. Chinese facial bones, however, tend to be even more
massive than in Java specimens, the skull walls thicker, and the mandibles
more robust. These local specializations also vary from the Homo erectus
specimens found in Africa (discussed below).
Causes of the very thick skulls of Homo erectus (roughly twice as thick as
those of modern humans) may have been a defensive adaptation against trauma
from personal violence, including blows from behind (Boaz and Ciochon 2004).
This view is supported by at least ten cases of healed depressed fractures
found in Zhoukoudian skulls by Weidenreich (1943).
Material culture of Chinese Homo
erectus: In excavations which lasted (with wartime interruptions)
from 1921-1982, the Longghushan cave site revealed over 100,000 artifacts
of worked stone and cut or burned animal bone, the latter often found in
the same levels producing Homo erectus fossils. The lithic artifacts,
first systematically recorded in 1931, and dominated by quartz flakes, represent
a Mode 1 or flake tool industry. Tool forms include retouched or sharpened
flakes, scrapers, core tools or choppers, and pointed awls used for piercing.
When discovered in the 1920s-30s, these were the first significant artifactual
remains to be found in situ with hominid fossils. Since initial
descriptions in the late 1930s, however, their interpretation has been rife
with controversy (Boaz et al. 2000; Boaz and Ciochon 2004).
An abundance of animal bones found at Zhoukoudian included thousands of deer
bones, some charred by fire. Given these apparent food remains, plus numerous
stone tools, original interpretations of the cave site portrayed it as a
home base for bands of Homo erectus who subsisted by hunting and
gathering. Evidence of fire in levels containing burned bone suggested cooking,
and the use of fire for warmth seemed consistent with this northernmost
settlement area for Homo erectus. Bone artifacts including cut marks
from stone tools were identified by Henri Breuil (1939), who visited China
several times in the 1930s. Signs of possible cannibalism were also seen
by Breuil (1939) and Weidenreich (1943) in breakage and widening of the foramen
magna of several skull bases, possibly to remove the brain.
Reexamination of the evidence, however, has significantly altered views about
a hunting subsistence for Homo erectus at Zhoukoudian. The overall
sample of hominid bones itself provided the first important clues that the
caves may have served other functions. Weidenreich (1943) first remarked
on the fragmentary nature of the Homo erectus fossil assemblage at
Zhoukoudian, which generally lacked long bones and extremities, and where
skulls had been broken up apparently even before their deposition in cave
sediments. This has been confirmed by recent, detailed examination of the
remains at Zhoukoudian locality I by Boaz et al. (2000), revealing that hominid
bones made up only half of one percent (0.5%) of the total bones at the site.
The high proportion of isolated teeth and skull parts, and the low incidence
of long bones or hands and feet, is typical of the bone accumulation in a
carnivore den. Some Homo erectus facial bones and crania (as first
noted by Weidenreich) show punctures and other marks typical of carnivores,
undoubtedly including the large, lion-sized Pleistocene cave hyena
Pachycrocuta brevirostris, whose bone remains are the most frequent
at the site. Hyenas also seem to have been responsible for the widening of
the foramen magnum on H. erectus remains, evidence which could no
longer pertain to cannibalism. Other evidence, nevertheless, of cut marks
by stone tools on Homo erectus Skull V (first noted by Weidenreich)
does show that cannibalism must have occurred at Zhoukoudian (Boaz and Ciochon
2004).
Postcranial
bones also exhibit typical hyena tooth marks and breakage, as part of hyaenid
scavaging or predation of Homo erectus. Many of the arm and leg bones
would have been totally consumed by hyenas or other carnivores, thus accounting
for their relative lack in the overall sample. The conclusion inevitably
drawn by Boaz et al. (first advanced in 1929 by the archaeologist W. C. Pei
[1938]) is that the Zhoukoudian caves, rather than being home bases for hominid
hunters, were, for much of the time, dens for the giant cave hyena. Controversy
has also persisted over the use of fire at the site. Ash in layers that had
been taken as signs of hearth fires showed no evidence of ph ytoliths (silica
particles) typically left by burning wood or other vegetation (Weiner et
al. 1998). This has supported the interpretation that most fires at Zhoukoudian
were not confined to hearth features, and thus could be due to natural causes
(Binford and Stone 1986). Yet some of the main layers with Homo erectus
fossils at Zhoukoudian cave (e.g., layer 10) also contain burned bone with
stone tools, which would seemingly indicate hominid use of fire, very likely
for cooking (Weiner et al. 1998).
Fig.6: Approximate dates of Homo erectus finds in four regions.
The flake tool (Mode 1) assemblages contain lithic items useful for defleshing
(scrapers and flakes) and for pounding bones to extract marrow (core choppers).
Binford and Ho (1985) proposed that Homo erectus subsisted by scavenging,
or foraging for meat left on bones in caves occupied primarily by cave hyenas,
wolves, or bears. This is supported by close examination of animal bones
at Zhoukoudian, which shows that cut marks made by Homo erectus with
quartz flakes overlie carnivore bite marks. While the caves at Zhoukoudian
often functioned primarily as dens for the cave hyena, they thus also must
have served as foraging areas for Homo erectus, who may have camped
nearby, possibly making shelters from tree branches (Boaz and Ciochon 2004).
Earlier Chinese sites: In the past
decade, several Lower Pleistocene hominid sites have been identified in China
(fig. 6). Among the most controversial is Longgupo Cave on the Yangtze River,
where a mandible fragment and teeth dated at 1.9 mya by ESR methods have
been compared to early African Homo habilis and H. ergaster
(Wanpo et al. 1995). Associated with the teeth were pitted and abraided cobble
tools of an exotic andesite-porphyrite. Also found at Longgupo were teeth
of Gigantopithecus, a huge Plio-Pleistocene ape also occurring with
Homo erectus at another Chinese site, Jianshi Cave, and at Tham Khuyen Cave
in Vietnam, dated at 475,000 BP (Ciochon et al. 1996). While debate continues
on the hominid identification of the Longuppo teeth, the site is of
potentially great significance in terms of initial dispersal from Africa.
Other early tool evidence comes from the Nihewan Basin in north China (40
N), a lacustrine region known for Villefranchian-age fauna (Zhu et al. 2001).
While the site lacks hominid fossils, a Mode 1 flake tool assemblage of over
3000 items including side- and end-scrapers has been found in layers dated
paleomagnetically to 1.36 mya, a relatively early date for hominids in a
north-temperate zone.
Some 900 km to the south in Lantian county, a partial cranium from Gongwangling
on the Yellow River represents China’s earliest known Homo erectus
fossil, dated about 1.15 mya (Etler 1996). By this period, a wide adaptive
range is indicated for Chinese Homo erectus. One skull of a female
at Lantian, aged about 30, has a cranial capacity of 780 cc, comparable to
individuals from Koobi Fora and Sangiran. By 800,000 years ago, bifacial
stone tools were being made in the Bose Basin in south China, partly resembling
an Acheulean industry but lacking handaxes (Hou Yamei et al. 2000).
Zhoukoudian’s
date range is also under revision, along with that of several other Middle
Pleistocene Homo erectus sites in China (see information in Etler
2004). In 1985, uranium isotope dating gave absolute dates on hominid-bearing
layers at Zhoukoudian’s Localities 1 and 2 from 290,000 - 230,000 BP.
Yet the upper strata have recently been redated to be substantially earlier,
at 410,000 BP, while the lowest hominid layer is redated at 670,000 BP. Chinese
Homo erectus occupations from 670,000-400,000 occurred not only at
Zhoukoudian, but also at Tangshan Hill near Nanjing, in Yunxian at Quyuanhekou
(both about 620,000-580,000 BP), and the Hexian site at Anhi (over 400,000
BP). The Nanjing and Zhoukoudian Homo erectus specimens seem close
in morphology, and Middle Pleistocene faunal assemblages from the two sites
are very similar.
Later Chinese hominids: Based on
these revised dates, fossil evidence of Homo erectus is missing in
China between about 400,000 and 280,000 BP. Later hominids then appear with
more rounded skulls and (often) larger brain cases, including a young male
from Jinniushan dated at 280,000 years ago, with a modern-sized cranium of
1400 cc. At Hexian, a well-preserved Homo cranium (10 25 cc) with reduced
brow ridges has been dated to about 200,000 BP, contemporary with the Dali
cranium (fig.7), which shows large brow ridges and a flat, high face. The
still later Mapa cranium (about 132,000 BP) may be contemporary with Homo
soloensis populations from Java’s Ngandong deposits. Controversy
persists on whether Homo heidelbergensis populations migrated into
China and overlapped the latest Homo erectus groups as a separate
species, or there was a more gradual, in situ transition. Fig.7: Skull from Dali, China (photo: Athena Review, from cast at
AMNH).
Homo habilis and Homo erectus in
Africa: By the late 1970s it was evident that co-occurence
of two or more hominid species had occurred in east Africa between 2.4 and
1.8 mya, including some combination of australopithecines, Homo habilis,
and/or Homo erectus (Walker 1981). These three taxa are often subdivided
on the basis of skull form, dentition, and other features into at least seven
different species, including the gracile (A. africanus) and robust
(A. robustus and A. boisei) australopithecines, the latter
also called Paranthropus; Homo habilis (split into H.
habilis and H. rudolfensis); and Homo erectus (split into
H. erectus and H. ergaster). Evolution of multiple hominid
species in east Africa within a few hundred thousand years provides a convincing
case of adaptive radiation as portrayed in the “punctuated equilibria”
evolutionary model (Eldredge and Gould 1972; Walker 1981). This would contrast
with long periods of relative “stasis” or a lack of dramatic
evolutionary change, as perhaps occurred in the earlier Javan Homo
erectus.
In 1959, Louis Leakey found remains of a juvenile hominid (OH 5) near flake
tools in Olduvai Gorge, Tanzania, for which he created the taxon Homo
habilis or “handy man” (Leakey, Tobias and Napier 1964). Nearby
in the same Late Pliocene sediments, dated 2.2-2.0 mya were also remains
of the large-jawed and smaller brained Australopithecus boisei. The
Homo habilis skull had a cranial capacity of about 675 cc, bigger
than the still extant australopithecines, but smaller than the later Homo
erectus, a partial skull of which Leakey found the next year, 1960, dated
at about 1.4-1.25 mya (OH 9). (This, and another fragmentary Homo
erectus cranium from Olduvai, OH-12, have sometimes been called H.
erectus Leakeyi). The only other African Homo erectus fossils known ca.
1960 were two mandibles from Ternafine, Algeria dated about 600,000 BP (Arambourg
1957), and the relation between Homo habilis and H. erectus
in east Africa remained unresolved.
While Tobias and von Koenigswald both saw links between Olduvai’s Homo
habilis and Javan Homo erectus, Leakey and others considered H.
erectus an aberrant line largely confined to Asia. The latter position
became more difficult to maintain by the mid 1970s, after several more examples
of Homo erectus had been found in Africa. These included a partial
H. erectus skull and face from Swartkrans in South Africa, discovered
in 1969 by Ronald Clark and dated at 1.5 mya (Clark et al. 1970); and a wide
range of Homo erectus fossils dated 1.75-1.50 mya from Lake Turkana
(fig.3), found amid Australopithecus robustus and Homo habilis
remains.
As at Olduvai
and other Rift Valley sites, the Lake Turkana fossil hominids
(discussed
in Cachel 2004) have been discovered mainly as surface finds from
sediments
dated by potassium/argon methods. Fossil zones on the east side of Lake
Turkana
(discussed in Cachel 2004) include areas of exposed Lower Pleistocene
sediments
at Ileret, Koobi Fora, and Allia Bay, the first two well correlated in
date
(Walker 1981). The nearly complete cranium KNM-ER 3733 from Koobi Fora
(fig.8), found in 1975 by Richard Leakey and dated to 1.75 mya, shows
closed cranial
sutures and erupted third molars, and represents a mature adult who was
probably
female. The low cranial vault (also typical of Asian Homo erectus)
has a brain volume of 848 cc. Also from Koobi Fora is a male skull (KNM-ER
3883) dated to 1.57 mya. The brain size of at least 804 cc. is similar to
that of ER 3733. These individuals are comparable in cranial capacity and
some other aspects of form to several Homo erectus skulls from Sangiran,
Java predating 1.51 mya, as well as to skulls from Dmanisi in Georgia (see
below).
Fig.8: KNM-ER 3733, a Homo erectus/ergaster skull
from Koobi Fora on Lake Turkana, Kenya (photo: Athena Review, from cast
at AMNH).
On the northwest side of Lake Turkana, Lower Pleistocene sediments revealed
in 1984-6 the relatively complete fossil skeleton of a 10-12 year old Homo
erectus youth (KNM-WT 15000), found by Kimoya Kimeu, Richard Leakey,
and Alan Walker (Leakey et al. 1993). The skeleton (fig.x), called
“Nariokotome Boy” after the nearby west Turkana town, and dated
1.55-1.51 mya, is relatively tall (5’3” or 168 cm) with limb bones
in the modern range and a cranial capacity of 880-900 cc. The skull of WT
15000 is generally more robust than that of the slightly earlier KNM-ER 3733
from Koobi Fora, an example of the physical variability seen in Homo
erectus.
Material culture associations for Homo erectus at Lake Turkana include
detailed cut marks on animal bone which suggests more careful and deliberate
meat extraction than might be expected of scavengers. Reduced sexual dimorphism
seen in the Koobi Fora hominids may also relate to a meat-enhanced diet (Cachel
2004; Cachel and Harris 1998).
More evidence of Homo habilis emerged at Omo, Ethiopia, north of Lake
Turkana (Boaz and Howell 1977); and at Koobi Fora (ER 1813), where a combination
of rounded skull with large teeth led to a new species designation Homo
rudolfensis. Hominid fossils from Omo support a theory of gradual, in
situ evolution from Homo habilis to Homo erectus in east
Africa from 2.4 to 1.8 mya (Cronin et al. 1981). Alternatively, based on
a low body mass and apparent terrestrial/climbing abilities, Wood and Collard
(1999) propose reclassifying the two closely related taxa of H. habilis
and H. rudolfensis as australopithecines. The larger Homo
taxa, starting with African Homo erectus/ergaster by 1.9 mya,
show different adaptations corresponding to larger body mass and specialized
bipedal walking abilities.
The identification of Homo
ergaster: The taxon of Homo ergaster
was first defined in 1975 by C. Groves and V. Mazak, split from Homo erectus
via cladistic analysis on a single mandible from Lake Turkana (KNM-ER
992). Homo ergaster, Greek for “handyman” (equivalent to
Louis Leakey’s Homo habilis) has since been used to distinguish
Asiatic from African Homo erectus. The replacement theory holds that
Homo ergaster is the common ancestor of both African and Asian Homo
erectus (the latter, evolving into a separate species) and later forms
of Homo leading to modern humans. This distinction has been questioned
by recent findings at Bouri, Ethiopia, of Homo erectus skulls from
1 mya. Their similar morphology to Asian Homo erectus indicates there
may be no need for the separate African species of Homo ergaster (Asfaw
et al. 2002).
More evidence for long-term variability in Homo erectus comes with
the recent discovery of a skull at
Olorgesailie, a Middle
Pleistocene lakebed site in southern Kenya. The small, relatively gracile
Homo erectus cranium shows affinities with both Lake Turkana and Dmanisi
hominids (Potts et al. 2004). Dated at 0.9 mya, it is linked with Acheulean
technology used in the butchering of lakeside game.
Travels out of Africa: The initial
spread of Homo erectus/ ergaster from Africa occurred by about
1.8 mya to Eurasia as well as the Sunda shelf region (Java). The recent
discoveries at Dmanisi, Republic of Georgia, of several relatively small-brained
hominid remains together with Oldowan tools (Gabunia and Vekua 1995; Gabunia
et al. 2000) adds to the argument against any significant time gap between
emergence of Homo and large-scale hominid migrations.
In 1984 the Dmanisi Pleistocene deposits yielded their first evidence of
stone tools. Subsequent excavations by Georgian and German archaeologists
led to the discovery of early hominid remains with Oldowan (Mode 1) stone
tools, and 29 species of Villefranchian fauna from the Late Villanian and
Early Biharian Mammal Ages, dating from 2.0 to 1.5 mya. Villefranchian fauna from the Late Villanian and
Early Biharian Mammal Ages, dating from 2.0 to 1.5 mya.
Dmanisi
hominids: All of this has transformed Dmanisi into a site
of major im portance. By 2002, Dmanisi had already produced over twenty fossilized
remains of Lower Pleistocene hominids, including three skulls, three lower
jaws (mandibles) with intact teeth, and postcranial parts including leg,
arm, and finger bones or metatarsals (Vekua et al. 2002). While stature
approaches that of Homo erectus/ergaster, brain size is relatively small,
at times near the upper range of Homo habilis or even australopithecines.
[Fig. 9: Hominid skull D-2282 from Dmanisi (photo: courtesy David
Lordkipanidze).]
The site’s chronology has been determined by the K-Ar date of the Mashavera
Basalt underlying the fossils at 1.85 mya, while an upper date of 1.8-1.6
mya is based on volcanic ash dating and faunal analysis. Given the presence
of more Palearctic than Paleotropical species, the Lower Pleistocene site,
located near the confluence of two rivers, had a moderately dry Mediterranean
climate. Two small adult or sub-adult hominid skulls with
endocranial volumes below 800 cc were discovered in 1999. The smaller (D-2282),
possibly from a female, includes parts of the maxilla and a cranial vault
with a capacity of about 650 cc (fig. 9). The larger skull (D-2280), a nearly
compete calvaria with a braincase of 775 cc (fig. 103), has more robust brow
ridges and may represent a male. A third skull was found in 2001. At first
assigned to Homo ergaster, Dmanisi hominid fossils were reclassified
in 2002 as a new species, Homo georgicus. Fig.10: Hominid skull D-2280 from Dmanisi (photo: courtesy David
Lordkipanidze).
Oldowan stone tools and subsistence at Dmanisi:
Primitive flake and core tools found at Dmanisi, identified
as an Oldowan or Mode 1 lithic industry, were made from alluvial cobbles
of silicified volcanic tuffs and quartz, found along terraces of the Mashavera
and Phinezauri Rivers. Cores fashioned from cobbles or cobble fragments (fig.
11) sometimes show rough striking platforms, with smaller pebble tools resembling
the cores. Use wear appears on flake edges as small notches or splin terings,
with occasional edge retouch or sharpening, including a burin made from a
large flake.
Discoveries
at Dmanisi of Mode 1 tools associated with early hominids indicate that the
causes of far-ranging migrations before 1.6 mya relate more to enhanced mobility
and ecological adaptations, than to any sophistication of stone tool manufacture
and related cognitive abilities. In the view of David Lordkipanidze, Deputy
Director of the Georgian State Museum (pers. comm.), “the Dmanisi finds
invalidate the theory that the development of advanced stone tool technology
enabled early humans to finally expand out of Africa.”
Fig.11: Stone tools of Oldowan (Mode 1) type from Dmanisi (courtesy
David Lordkipanidze).
Homo erectus in Western Europe: Current
evidence shows two distinct phases of Homo erectus in Europe, with
the first occurring in the Lower Pleistocene (Milliken 2004). While Dmanisi
represents initial hominid migrations from northeastern Africa, another very
early northwestern movement came across the Strait of Gibraltar to the
Guadix-Baza basin in southeastern Spain. During the past decade, Lower
Pleistocene hominid occupations have been revealed at Barranco León-5
and Venta Micena from around 1.7 mya (with fragmentary hominid skeletal remains),
and at Fuentenueva-3 from1.6-1.4 mya. Faunal remains and lithic artifacts
at these sites suggest positive correlations between the activities of large
carnivores such as sabre-tooth cats, and hominid scavenging subsistence using
Mode I stone tools.
After a hiatus
of at least 500,000 years came a second phase of Homo erectus in Europe
(0.9 -0.6 mya), corresponding with the transition from Lower to Middle
Pleistocene. Evidence at several sites in Spain (Atapuerca) and Italy (Monte
Poggiolo, Isernia la Pineta, and Ceprano) is slightly earlier than, or
contemporary with that of Chinese Homo erectus populations at Lantian
and the earlier occupations at Zhoukoudian, Nanjing, and Hexian. During the
second European phase Homo erectus retained Asiatic, Oldowan tool
traditions, probably related to scavenging subsistence modes. In Italy,
tool-making episodes at Monte Poggiolo predating 780,000 BP are evidenced
by thousa nds of chert flakes, while at Isernia la Pineta (730,000 BP), abundant
bones including those of elephants and bison were defleshed by simple,
unretouched flakes. At Atapuerca in northern Spain, bones of deer, boars,
and hominids were broken with stone tools for marrow extraction, indicating
that by ca. 750,000 BP cannibalism was part of the local diet.
Fig.12: Acheulean handaxes from the River Somme valley, illustrating Mode 2 tools (Museé de Picardie,
Amiens; photo: Athena Review).
The end of the later European phase coincides with the advent of Homo
heidelbergensis and the introduction of Acheulean, Mode 2 stone tools
(fig.12) into Europe by about 600,000-500,000 BP. With this came more efficient
subsistence practices relating to hunting and gathering. This correlates
with a dramatic increase in occupation sites in Europe, which begin to be
found as far north as the English Channel
(as at Saint-Acheul,
France, type site for the Acheulean handaxe), indicating significant population growth and expansion of adaptive
ranges in Homo groups by 500,000 BP.
[Written and researched by AR editorial staff.]
References:
Abatte, E.A., et al., 1998. “A one-million-year-old Homo cranium from
the Danakil (Afar) depression of Eritrea. Nature 393: 458-460.
Antón, S.C., 1999. “Cranial growth in Homo erectus: How credible
are the Ngandong juveniles?” Amer. Journal of Physical Anthropology
108: 223-236.
Antón, S.C., 2002. “Evolutionary significance of cranial variation
in Asian Homo erectus.” Amer. Journal of Physical Anthropology 118:
301-323.
Arambourg, C. 1957. “Récentes décovertes de
paléontologie humaine réalisées en Afrique du Nord
française.” In Livingstone (ed.) Proceedings of the Third Pan-African
Congress on Prehistory.
Asfaw, B., W.H. Gilbert, Y. Beyene, W.K. Hart, P.R. Renne, G.WoldeGabriel,
E.S. Vrba, and T.D. White.2002. “Remains of Homo erectus from Bouri,
Middle Awash, Ethiopia.” Nature 416: 317-320.
Binford, L.R. and C.K. Ho. 1985. “Taphonomy at a distance: Zhoukoudian,
‘the cave home of Beijing man?’”Current Anthropology 26:413-42.
Binford, L.R. and N.M. Stone 1986. “Zhoukoudian: A closer look.”
Current Anthropology 27:453-75.
Boaz, N.T. and R.L. Ciochon. 2004. Dragon Bone Hill. Oxford, Oxford University
Press.
Boaz, N.T. and F. C. Howell. 1977. “A gracile hominid cranium from Upper
Member G of the Shungura Formation, Ethiopia.” Amer. Jour. Physical
Anthropology 46: 93-108.
Boaz, N.T. et al. 2000. “Large mammalian carnivores as a taphonomic
factor in the bone accumulation at Zhoukoudian.” Acta Anthrop. Sinica,
Suppl.19:224-34.
Breuil, H. 1939. “Bone and antler industry of the Choukoutien Sinanthropus
site.” Palaeontologica Sinica117:1-93.
Brunet, M., et al. 2002. “A new Hominid from the Upper Miocene of Chad,
Central Africa.” Nature 418:145-151.
Cachel, S. and J.W.K. Harris. 1998. “The Lifeways of Homo erectus Inferred
from Archaeology and Evolutionary Ecology: A Perspective from East Africa.”
In M.D. Petraglia & R. Korisettar (eds.) Early Human Behaviour in Global
Context. The Rise and Diversity of the Lower Palaeolithic Record, pp.108-132.
Cann, R.L., M. Stoneking, and A.C. Wilson 1987. “Mitochondrial DNA evolution
and human evolution.” Nature 325:31-36.
Ciochon, R.L. et al. 1996. “Dated co-occurrence of Homo erectus and
Gigantopithecus from Tham Khuyen Cave, Vietnam.” Proc.National Acad.
of Sciences, USA 93:3016-20.
Clark, R.J, F.C. Howell, and C.K. Brain. 1970. More evidence of an advanced
Hominid at Swatrkrans.” Nature 2254: pp.1219-1222.
Cronin, J.E. et al. 1981. “Tempo and mode in hominid evolution.”
Nature 292:113-122.
Daniel, G.I. 1950. A Hundred Years of Archaeology. London, Duckworth.
Dubois, Eugene. 1894. Pithecanthropus erectus. Eine menschenaehnliche
Uebergangsform aus Java. Batavia, Landsdrukkerij.
Dubois, Eugene. 1896. “On Pithecanthropus erectus, a transitional form
between man and the apes.” Trans.Royal Dublin Soc., ser.2, vol.6, pp.
1-18.
Eldredge, N. and S.J. Gould 1972. “Punctuated equilibrium: an alternative
to phyletic gradualism.” In Schopf T.J.M. (ed.) Models in Palaeobiology.
San Francisco, Freeman, pp. 82-115.
Etler, D. 1996. “The Fossil Evidence for Human Evolution in Asia.”
Annual Rev. Anthro. 25:275-301.
Foley, R. 2001. “In the Shadow of the Modern Synthesis?” Evolutionary
Anthropology 10:5-14.
Gabunia L. and A. Vekua 1995. “A Plio-Pleistocene hominid from Dmanisi,
East Georgia, Caucasus.” Nature.373:509-512
Gabunia, L., A. Vekua, D. Lordkipanidze, C. Swisher III, R. Ferring, A. Justus,
M. Nioradze. M. Tvalchrelidze, S. Antón, G. Bosinski, O. Joris, M-A.-de
Lumley, G. Majsuradze, A. Mouskhelishvili 2000. “Early Pleistocene Hominid
Cranial Remains from Dmanisi, Republic of Georgia: Taxonomy, Geological Setting
and Age.” Science 288:1019-1025.
Groves, C.P, and V. Mazak 1975. “An Approach to the Taxonomy of the
Hominidae: Gracile Villafrancian hominids of Africa. Casopis Mineral Geolo.
20:225-247.
Haeckel, E. 1892 (orig.1868). The History of Creation. (4th Eng. ed.) London,
Kegan Paul, Trench, Trubner & Co.
Hou, Y. et al. 2000. “Mid-Pleistocene Acheulean-like Stone Technology
of the Bose Basin, South China.” Science 287: 1622-1626.
Howells, W.W. 1981. “Homo erectus in human descent: ideas and
problems.” in B.A. Sigmon & J.S. Cybulski (eds) Homo erectus: Papers
in Honor of Davidson Black, pp. 63-86. Toronto, Univ. of Toronto Press.
Huffman, O.F. 2001. “Geologic context and age of the Perning/Mojokerto
Homo erectus, East Java.” J.of Human Evolution 40:353-62.
Huxley, T. H. 1863. “On Some Fossil Remains of Man,” in Evidence
as to Man’s Place in Nature. London, Williams and Norgate.
Jacob, T. 1973. “Palaoanthropological discoveries in Indonesia with
special reference to the finds of the last two decades.” J. of Human
Evolution 2:473-85.
Jacob, T. 1981. “Solo Man and Peking Man.” in B.A. Sigmon &
J.S. Cybulski (eds.), op. cit., pp.87-104.
Larick, R. and R.L. Ciochon 1996. “The African Emergence and dispersal
of the genus Homo.” American Scientist 84:538-552.
Larick, R. et al. 2001. “Early Pleistocene 40Ar/39/Ar ages for Bapang
Formation hominins, Central Java, Indonesia.” Proc. Nat. Acad. of Sciences
98:4866-71.
Leakey, L., P.V. Tobias, and J.R.N. Napier 1964. “A new species of the
genus Homo from Olduvai Gorge.” Nature 202:7-9.
Lordkipanidze, D. 2003. Personal communication.
Mayr, E. 1950. “Taxonomic categories in fossil hominids.” Cold
Spring Harbor Symposia on Quantitative Biology 15:109-118.
Mayr, E. 1963. “The taxonomic evaluation of fossil hominids.” In
S.L. Washburn (ed.) Classification and Human Evolution. Chicago, Aldine.
Morwood, M. et al. 1998. “Fission-track ages of stone tools and fossils
on the east Indonesian island of Flores.” Nature 392: 173-176.
Oppennoorth, W.E.F. 1932. “Homo (Javanthropus) soloensis: Een pleistocene
mensch van Java.” Wetenschappelijke medeligen Dienst van den Mijnbrouw
in Nederlandsch-Indië 20:49-63.
Rightmire, G.P. 1990. The Evolution of Homo erectus: Comparative Anatomical
Studies of an Extinct Human Species. Cambridge, Cambridge Univ. Press.
Shipman, P. 2001. The Man Who Found the Missing Link. New York, Simon &
Schuster.
Swisher, CC., G.H. Curtis, Y. Jacob, A.G. Getty, A. Suprojo, Widiasmoro.
1994. “Age of the earliest known hominids in Java, Indonesia. Science
263:1118-1121.
Swisher C.C., W.J. Rink, H.P. Schwarcz, and S.C. Antón 1997. “Dating
the Ngandong Humans.” Science 276: 1575-1576.
Swisher, C.C., G.H. Curtis, and R. Lewin. 2000. Java Man. New York, Scribner.
Tattersall, I. 1995. The Fossil Trail: How We Know What We Think We Know
about Human Evolution. New York, Oxford University Press.
Tattersall, I. 2000. “Paleoanthropology: the last half-century.”
Evolutionary Anthropology 9:2-16.
Tattersall, I. and G.J. Sawyer. 1996. “The Skull of Sinanthropus from
Zhoukoudian, China: A New Reconstruction.” Jour. Human Evolution.
Vekua, A., D. Lordkipanidze, G.P. Rightmire, J. Agusti, R. Ferring, G.
Maisuradze, A. Mouskhelishvili, M. Nioradze, M. Ponce de Leon, M. Tappen,
M. Tvalchrelidze, C. Zollikofer 2002. “A New Skull of Early Homo from
Dmanisi, Georgia.” Science 297: 85-89.
Von Koenigswald, G.H.R. 1956. Meeting Prehistoric Man. Thames and Hudson.
Von Koenigswald, G.H.R and F. Weidenreich 1939. “The relationship between
Pithecanthropus and Sinanthropus.” Nature 144: 926-929
Walker, A. 1981. “The Koobi Fora hominids and their bearing on the origins
of the genus Homo.” In B.A. Sigmon & J.S. Cybulski (eds.) Homo erectus:
Papers in Honor of Davidson Black, pp.193-216. Univ. of Toronto Press.
Walker, A.and R. Leakey, (eds.). 1993. The Nariokotome Homo erectus skeleton.
Cambridge, Harvard Univ. Press.
Wanpo., H. et al. 1995. “Early Homo and associated artefacts from
Asia.” Nature 378:275-278.
Weidenreich, F. 1943. “The skull of Sinanthropus pekinensis: a comparative
study on a primitive hominid skull.” Palaeontologia Sinica, New Series
D 10.
Weidenreich, F. 1945. “Giant early man from Java and south China.”
Anthropological Papers, American Museum of Natural History 43: 205-90.
Weiner, S. et al. 1998. “Evidence for the use of fire at Zhoukoudian,
China.” Science 281: 251-53.
Wolpoff, M. and A. Thorne. 1991. “The case against Eve.” New Scientist,
June 22, 1991: pp.37-41.
Wood, B. and M. Collard 1999. “The Human Genus.” Science 284:65-71.
Zhu, R. et al. 2001. “Earliest presence of humans in Northeast Asia.
Nature 413: 413-417
This article appears on pages 16-24 of Vol.4 No.1 of Athena
Review.
|
|