Title: Early Hominins
1Early Hominins
2AustralopithecinesThe earliest Hominins
- East African fossil finds
- 4-3 mya bipedal although these animals probably
also were comfortable in the trees - From Ethiopia, Tanzania, Kenya
- Great Rift Valley
- Environment has changed
- Hadar in the Afar depression of Ethiopia now dry,
used to be wooded - Laetoli in Tanzania bipedal footprints _at_ 3.6 mya
in mud of a wetland area
3Maps of Africa (see http//81.0.149.237/frie_med
ier/Map_of_Africa.jpg and http//www.worldatlas.co
m/webimage/countrys/aflnd.htm)
4AustralopithecinesThe earliest Hominins
- South African fossil finds
- All the main finds from South Africa
- Taung child
- Raymond Dart in 1925
- The first Australopithecine ever discovered
- Australopithecus africanus
- Dates to about 3-2 mys
- Mrs. Ples, also A africanus confirmed the find
was a bipedal hominid
5Maps of Africa (see http//81.0.149.237/frie_med
ier/Map_of_Africa.jpg and http//www.worldatlas.co
m/webimage/countrys/aflnd.htm)
6Gracile Australopithecines A anamensis
- Australopithecus anamesis
- Kenya
- 3.9-4.2 mya
- Small hominin
- Teeth like A. afarensis
- Long bones suggest bipedalism
- Homo from the neck down and head like
Australopithecus - https//www.msu.edu/heslipst/contents/ANP440/anam
ensis.htm
7Gracile Australopithecines A afarensis
- Australopithecus afarensis
- 4-3 mya in East Africa
- Laetoli, Tanzania
- Teeth and jaws
- Footprints3.6 mya
- Hadar, Ethiopia
- Lucy40 of skeleton found
- Pelvis shows she was bipedal
- 3.2 mya in semi-arid savanna
8Gracile AustralopithecinesA afarensis
- Australopithecus afarensis differs from A
africanus in terms of date (earlier) and location
(E Africa) - Incisors and canines large and tooth rows
converge - Often has sagittal crest and temporo-nuchal crest
- Largest males were 150 cm tall and cranial
capacity was about 415 cc - (http//anthropology.si.edu/humanorigins/ha/afar.h
tml and (https//www.msu.edu/heslipst/contents/AN
P440/afarensis.htm)
9Gracile AustralopithecinesA africanus
- Rounded brain case, well-develop forehead and
moderate brow ridges, projecting face - Cranial capacity between 428cc and 485cc
- Adults 105-135 cm tall
- Chinless jaw of Miocene apes but broad incisors
and short canines as well a relatively small
molarsdental function similar to humans - Broad pelvis, lumbar curve and hip joint and
femoral bone analysis suggest bipedalism - 3-2 mya so more recent than A afarensis
10Gracile AustralopithecinesA africanus
- The Taung Child A africanus
- Discovered in 1925 by Raymond Dart
- Child less than 3 years old
- Dates to about 3.2 mya
- Foramen magnum position and short incisors and
canines were human-like rather than ape like - Biped
- Mrs.Ples found in 1940s confirmed the discovery
of A africanus as a biped - (http//anthropology.si.edu/humanorigins/ha/afri.h
tmlhomo and https//www.msu.edu/heslipst/content
s/ANP440/africanus.htm)
11Robust Australopithecines
- Date between 2.5 mya and 1 mya in East Africa and
South Africa - A boisei (http//anthropology.si.edu/humanorigins/
ha/bos.html) - East African
- 2.3-1.3 mya
- A robustus (http//anthropology.si.edu/humanorigin
s/ha/rob.htm) - South African
- 1.8-1 mya
- Should they all be called Paranthropus rather
than Australopithecus?
12Robust Australopithecines
- In comparison to gracile australopithecines they
had - Thick jaws
- Large molars and premolars
- Small incisors
- Massive muscle attachments for chewing
- Large sagittal crests for chewing
- A boisei more extreme than A robustus in these
features - Cranial capacity of both species of robust
australopithecine was 490-530cclarger than
gracile forms - Body size similar to A africanus so relative
brain size was larger than A africanus
13Robust AustralopithecinesA robustus
- Discovered in South Africa in 1938 when it was
given the name Paranthropus in contrast to A
africanus - Large teeth and jaw and flat face
- 1.8-1 mya
- A robustus ate vegetable foods but new studies do
not rule out other foods - Not ancestral to Homo species
- (http//anthropology.si.edu/humanorigins/ha/rob.ht
m) - (https//www.msu.edu/heslipst/contents/ANP440/ro
bustus.htm)
14Robust AustralopithecinesA boisei
- Mary Leakey and Louis Leakey discovered A boisei
at Olduvai Gorge in 1959 - Leakey called the new fossil Zinjantropus
- Now placed in the Australopithecines
- Extremely robust facial features
- Molar teeth, expanded premolars, massive and
thick jaw, large sagittal crest
(http//anthropology.si.edu/humanorigins/ha/bos.ht
ml) and (https//www.msu.edu/heslipst/contents/AN
P440/boisei.htm) - 2.3-1.3 mya in dry, open environment
- Questions about robust Australopithecines
- Some lived at same time as Homodid they make and
use tools found after 2.5 mya? - Are similarities in robust forms (ie A robustus,
A boisei and later H erectus due to evolutionary
convergence or ancestral linkages?
15Stone tools and hunks of rock
- Provenience
- Kind of rockcan be flaked and will lastflakable
and durable - Bilateral flakingboth sides of stone struck to
make and cutting edge - Retouching
- Striking platform
16Lines of Descent
- See page 180 of the text and http//anthropology.s
i.edu/humanorigins/ha/a_tree.html - Between 3 and 1 mya there were at least two
hominin lines - Robust australopithecines became extinct about 1
mya and were not ancestral to modern humans - Homo habilis was in direct lines of descent to H
sapiens
17Themes
- Complex jig-saw puzzle with pieces spread over
100s of miles and millions of years - Lots of ego involved in this work!
- Various species of Australopithecus existed
together and in sequence - A afarensis most likely ancestor of Homo
- Bipedal but not yet making toolsalso possibly
partially arboreal in some species - Sexual dimorphism especially in the robust forms
- Increase in cranial capacity indicating larger
brains over time