Australopithecus robustus
Australopithecus robustus
•Body similar to A. africanus, but larger and
more robust skull, jaws, and teeth
•Found primarily in cave deposits estimated at
1½ - 2 mya from Swartkrans and Kromdraai in
South Africa
•Massive face is flat or dished, with no forehead
and large brow ridges
•Relatively small front teeth, but massive
grinding teeth (molars and premolars) in a large
lower jaw
Australopithecus robustus, 3
•Most specimens have sagittal crests
•Diet would have been mostly coarse, tough
food that needed a lot of chewing
•Average brain size is about 530 cc
•Animala bones excavated with A. robustus
skeletons suggest to some workers that the
australopithecines may have used bones as
digging tools
Australopithecus boisei
•A. boisei existed between 2.1 and 1.1
million years ago
•Similar to A. robustus, but the face and
cheek teeth even more massive
•Cranial capacity averages about 530 cc
•Some experts consider A. boisei and A.
robustus to be variants of the same species
–Others place them in a separate genus,
Paranthropus
KNM--ER 406
KNM
Gracile vs. Robust
•Australopithecus afarensis and A. africanus
are known as gracile australopithecines,
because of their relatively lighter build,
especially in the face and teeth
–Gracile means slender, and in paleontology is
used as an antonym to robust
–Despite this, A. afarensis and A. africanus were
still more dentally robust than modern humans
Photograph by David Brill
1
Gracile vs. Robust, 2
•Australopithecus aethiopicus, A. robustus
and A. boisei are known as robust
australopithecines, because their skulls are
more heavily built
Discovery of this jaw in
1960 led Louis Leakey
to name a new species,
Homo habilis, as direct
ancestor of man, with
Homo erectus
representing an extinct
side branch
OH 7
–The jaws, cheek teeth, and face are the most
heavily built aspects of these fossil hominids
–The canine teeth are quite small in all of these
species
Photograph by John Reader
Homo habilis
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suggestion of evidence of tools found in
contemporary deposits
•Lived between about 2.4 and 1.5 million
years ago
•Similar to australopithecines in many ways
•Face is primitive, but projects less than in A.
africanus
Photograph by John Reader
KNM--ER 1813
KNM
Photograph by David Brill
Homo habilis, 2
•Back teeth are smaller than those of the
australopithecines, but still considerably
larger than modern humans
•Average cranial capacity, at 650 cc, is larger
than in australopithecines
–Brain size varies between 500 and 800 cc,
overlapping the australopithecines at the low
end and H. erectus at the high end
Homo habilis, 3
•Brain shape is more humanlike
–Bulge of Broca's area, essential for speech, is
visible in one H. habilis brain cast, indicating it
may have been capable of rudimentary speech
•H. habilis was about 127 cm (5'0") tall, and
about 45 kg (100 lb) in weight, although
females may have been smaller
2
Homo habilis, 4
KNMKNM-ER 1470
Homo rudolfensis
•Habilis has been a controversial species
–Some scientists have not accepted it, believing
that all H. habilis specimens should be assigned
to either the australopithecines or Homo erectus
–Many now believe that Homo habilis combines
specimens from two or three different species
•Homo habilis
•Homo rudolfensis
•Homo ergaster
Photographs by David Brill
Homo rudolfensis
•The species designation of Homo rudolfensis is much
debated
KNMKNM-ER 992
Homo ergaster
–Is it a separate species
–Is it an australopithecine rather than a homonine
•One of the main problems with H. rudolfensis species is that
there are no postcranial remains
–Large brains in conjunction with megadont postcanines
–Some researchers see the larger brain and tooth size as indicative
of allometric changes due to increased body size--rudolfensis and
habilis are the same, with the former the males and the later the
females
–Some see rudolfensis as the ancestor of habilis with a decrease in
brain size occurring
–Others see the two on completely different evolutionary lines
Photograph by Robert I.M. Campbell
KNMKNM-WT 15000
Homo ergaster
•Homo ergaster is one of the more problematic of
species designations
•Each researcher that sees ergaster as valid sees
different specimens as belonging or not belonging
•Most researchers see too little difference between
ergaster and erectus to form the basis of a species
•As a general rule of thumb, one can consider most
attributed ergaster specimens to be early erectus
geographically confined to Africa
Photographs by David Brill
3
Homo erectus
from Zhoukoudian
Weidenreich
Tattersall and Sawyer
Homo erectus
•Wolpoff claims that H. erectus is an invalid taxon,
though few accept this interpretation at this point
in time
•Others believe the material attributed to erectus
should be split into several different taxons
–Asian and later African material remaining as H.
erectus--not contributing to modern humans
–Early African material as H. ergaster
–European material as H. heidelbergensis
Photographs by David Brill
KNMKNM-ER 3733
Homo erectus
•An increase in brain size to approximately 900 cc
•Reduction in postcanine dentition and a decrease
in jaw size
•Vertical shortening of the face.
•Shortening arm bones, especially forearms to very
modern limb proportions
–Postcranial proportions are very similar to tropically
adapted modern humans
Photographs by David Brill
Homo antecessor
•Securely dated at 780 kyr
•Approximate brain size of 1000 cc
•Marked double-arched browridge
•Development of a more barrel-shaped chest
•The formation of an external nose
•Modern human size in terms of height
Gran Dolina Material
Homo antecessor
–like later Neanderthals and Chinese H. erectus
•Canine fossa but no expanded maxilla
–May be due to the individual's young age since others
(ATD 6-58) have an expanded maxilla
•Sharp nasal margin
•Shallow maxillary notch
•Reduced mandibular corpus thickness when compared to
H. ergaster or early H. erectus
•Small postcanines that resemble those of the habilines
•M3 reduced relative to M1
•Moderate taurodontism
–Characteristic of H. erectus and H. heidelbergensis)
•Large I2 dimensions that resemble H. heidelbergensis
Photograph by Javier Trueba
4
Homo antecessor
Homo heidelbergensis
from Arago
•An important feature that was discovered when the remains
were examined were cut marks that were present on most
of the material
–12 parallel cut marks on a temporal fragment where the
sternocleidomastoid muscle attaches
–Cut marks on two foot phalanges where the flexor muscle lies
•Dismemberment was the likely goal
•Faunal material shows the same cut marks as the hominid
remains
–Very few carnivore tooth marks indicates that hominids were
mainly responsible for processing the bones
•This is the earliest well-documented case of cannibalism in
a hominid population, and this information is important for
deciphering the behavior of early hominids
Photographs by David Brill
Homo heidlebergensis
•An increase in brain size to approximately 1200cc
•A shift in the widest part of the brain case from
the cranial base to the parietal regions
•The rear of the cranial vault becomes more
vertical
•A gradual reduction in cranial robusticity
•A decline in postcranial robusticity
•A tendency for a shift from shorter more robust
stature to taller, leaner bodies
Homo heidelbergensis
Mauer 1
Homo heidlebergensis
• 1907 Mauer sand pits in Germany
• Validated Schoetensack's
conviction that Pleistocene human
remains would be found in the
quarry
Age est. 500 kya (400 –700 kya)
– Associated with rhino, bear, elephant,
bison, deer, and horse
• Schoetensack (1908) named a new
species of hominid, Homo
heidelbergensis
– New species not justified by
describing unique anatomical
features of the species
– Lack of older or other specimens kept
heidelbergen sis from being accepted
Photograph by John Reader
Homo neanderthalensis
Neanderthal 1
Bodo: 600 kya
Arago: 400 kya
Photograph by Rheinisches Landesmuseum Bonn
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Homo neanderthalensis
Homo neanderthalensis
Mount Circeo
La Chapelle
Chapelle--aux
aux--Saints
Photographs by John Reader
Photograph by Ministry of Culture, Italy
Homo neanderthalensis
•An occipital bun
•A suprainiac fossa
•Position of the mastoid crest located behind the
external auditory meatus
•Position of the juxtamastoid crest located behind
the mastoid crest, and often larger than the
mastoid process
•Position of the mastoid process
•The supraorbital torus
•The supratoral sulcus
•A receding frontal
•Presence of lambdoidal flattening
Inner Ear Morphology
Drawings by C. David Kreger
• Another trait that is being looked at currently as a way of
distinguishing Neanderthals in the inner ear morphology
• Researchers are trying to determine if the Neanderthals had a
unique inner ear morphology that can be used
• When comparing the values of S/I, humans generally have a
value close to 1, chimpanzees have values greater than 1, and
Neanderthals have values less than 1
Neanderthal Features
Tattersall and Schwartz, 2001:199
Tattersall and Schwartz, 2001:196
Features of
Anatomically
Modern
Homo sapiens
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Homo sapiens
Homo sapiens
Qafzeh IX
Cro Magnon 1
30 –32 kya
Photograph by David Brill
90 - 100 kya
Photograph by David Brill
Homo sapiens
Klassies River Mouth
90 - 120 kya
References
• Leakey, M., F. Spoor, F. Brown, P. Gathogo, C. Kiarie,
L. Leakey, and I. McDougall (2001) New hominin genus
from eastern Africa shows diverse middle Pliocene
lineages. Nature 410, 433 –440.
• Lieberman, D. (2001) Another face in our family tree
Nature 410, 419 –420.
• Kreger, C.D. (2001) A look at modern human origins.
http://www.modernhumanorigins.com/
• Tattersall, I. and J. Schwartz (2001) Extinct Humans. New
York: Westview.
Photograph courtesy of the
South Africa Museum
Possible evolutionary
relationships of the hominids
• The five major genera,
with Kenyanthropus in
red, Homo in blue,
Paranthropus in green,
Australopithecus in black
and Ardipithecus in
yellow
– Question marks indicate
hypothetical or conjectural
relationships; horizontal
bars indicate uncertainty in
the species' temporal spans
• Lieberman, 2001
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