''Australopithecus'' (, ; ) is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of early
hominin
The Hominini form a taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera ''Homo'' (humans) and '' Pan'' (chimpanzees and bonobos) and in standard usage excludes the genus ''Gorilla'' (gorillas).
The t ...
s that existed in Africa during the
Late Pliocene
Late may refer to:
* LATE, an acronym which could stand for:
** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia
** Local-authority trading enterprise, a New Zealand business law
** Local average treatment effect, ...
and
Early Pleistocene
The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy, being the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time ...
. The genus ''
Homo
''Homo'' () is the genus that emerged in the (otherwise extinct) genus ''Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely relate ...
'' (which includes modern
humans
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
) emerged within ''Australopithecus'', as sister to e.g. ''Australopithecus sediba''. Also the genera ''
Paranthropus
''Paranthropus'' is a genus of extinct hominin which contains two widely accepted species: ''Paranthropus robustus, P. robustus'' and ''P. boisei''. However, the validity of ''Paranthropus'' is contested, and it is sometimes considered to be sy ...
'' and ''
Kenyanthropus
''Kenyanthropus'' is a hominin genus identified from the Lomekwi site by Lake Turkana, Kenya, dated to 3.3 to 3.2 million years ago during the Middle Pliocene. It contains one species, ''K. platyops'', but may also include the 2 million year ol ...
'' emerged within ''Australopithecus''. ''Australopithecus'' is a member of the subtribe
Australopithecina
Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally ''Australopithecus'' (cladistically including the genus, genera ''Homo'', ''Paranthropus'', and ''Kenyanthropus''), and it typically in ...
, which sometimes also includes ''
Ardipithecus
''Ardipithecus'' is a genus of an extinct hominine that lived during the Late Miocene and Early Pliocene epochs in the Afar Depression, Ethiopia. Originally described as one of the earliest ancestors of humans after they diverged from the chimpa ...
'', though the term "australopithecine" is sometimes used to refer only to members of ''Australopithecus''. Species include ''
A. garhi
''Australopithecus garhi'' is a species of australopithecine from the Bouri Formation in the Afar Region of Ethiopia 2.6–2.5 million years ago (mya) during the Early Pleistocene. The first remains were described in 1999 based on several skele ...
'', ''
A. africanus'', ''
A. sediba
''Australopithecus sediba'' is an extinct species of australopithecine recovered from Malapa Cave, Cradle of Humankind, South Africa. It is known from a partial juvenile skeleton, the holotype MH1, and a partial adult female skeleton, the par ...
'', ''
A. afarensis
''Australopithecus afarensis'' is an extinct species of australopithecine which lived from about 3.9–2.9 million years ago (mya) in the Pliocene of East Africa. The first fossils were discovered in the 1930s, but major fossil finds would not ta ...
,
A. anamensis,
A. bahrelghazali'' and ''
A. deyiremeda''. Debate exists as to whether some ''Australopithecus'' species should be reclassified into new genera, or if ''Paranthropus'' and ''Kenyanthropus'' are synonymous with ''Australopithecus'', in part because of the taxonomic inconsistency.
The earliest known member of the genus, ''A. anamensis'', existed in eastern Africa around 4.2 million years ago. ''Australopithecus'' fossils become more widely dispersed throughout eastern and southern Africa (the Chadian ''A. bahrelghazali'' indicates the genus was much more widespread than the fossil record suggests), before eventually becoming pseudo-extinct 1.9 million years ago (or 1.2 to 0.6 million years ago if ''Paranthropus'' is included). While none of the groups normally directly assigned to this group survived, ''Australopithecus'' gave rise to living descendants, as the genus ''Homo'' emerged from an ''Australopithecus'' species
[Toth, Nicholas and Schick, Kathy (2005). "African Origins" in ''The Human Past: World Prehistory and the Development of Human Societies'' (Editor: Chris Scarre). London: Thames and Hudson. Page 60. ] at some time between 3 and 2 million years ago.
''Australopithecus'' possessed two of three duplicated genes derived from ''
SRGAP2
SLIT-ROBO Rho GTPase-activating protein 2 (srGAP2), also known as formin-binding protein 2 (FNBP2), is a mammalian protein that in humans is encoded by the ''SRGAP2'' gene. It is involved in neuronal migration and differentiation and plays a criti ...
'' roughly 3.4 and 2.4 million years ago (''
SRGAP2B'' and ''
SRGAP2C
SLIT-ROBO Rho GTPase activating protein 2C is a protein in humans that is encoded by the SRGAP2C gene.
Cortical development gene Slit-Robo Rho GTPase-activating protein 2 (SRGAP2) has been highly conserved over mammalian evolution, and human is th ...
''), the second of which contributed to the increase in number and migration of
neurons
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...
in the human brain. Significant changes to the hand first appear in the fossil record of later ''A. afarensis'' about 3 million years ago (fingers shortened relative to thumb and changes to the joints between the
index finger
The index finger (also referred to as forefinger, first finger, second finger, pointer finger, trigger finger, digitus secundus, digitus II, and many other terms) is the second digit of a human hand. It is located between the thumb and the mid ...
and the
trapezium and
capitate
The capitate bone is a bone in the human wrist found in the center of the carpal bone region, located at the distal end of the radius and ulna bones. It articulates with the third metacarpal bone (the middle finger) and forms the third carpomet ...
).
Taxonomy
Research history
![Australopithecus africanus Taung face (University of Zurich)](https://upload.wikimedia.org/wikipedia/commons/0/0b/Australopithecus_africanus_Taung_face_%28University_of_Zurich%29.JPG)
The first ''Australopithecus'' specimen, the
type specimen
In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...
, was discovered in 1924 in a lime quarry by workers at
Taung
Taung is a small town situated in the North West Province of South Africa. The name means ''place of the lion'' and was named after Tau, the King of the Barolong. ''Tau'' is the Tswana word for lion.
Education
High,Secondary and Middle Schools ...
, South Africa. The specimen was studied by the Australian anatomist
Raymond Dart
Raymond Arthur Dart (4 February 1893 – 22 November 1988) was an Australian anatomist and anthropologist, best known for his involvement in the 1924 discovery of the first fossil ever found of ''Australopithecus africanus'', an extinct homi ...
, who was then working at the
University of the Witwatersrand
The University of the Witwatersrand, Johannesburg (), is a multi-campus South African Public university, public research university situated in the northern areas of central Johannesburg. It is more commonly known as Wits University or Wits ( o ...
in
Johannesburg
Johannesburg ( , , ; Zulu and xh, eGoli ), colloquially known as Jozi, Joburg, or "The City of Gold", is the largest city in South Africa, classified as a megacity, and is one of the 100 largest urban areas in the world. According to Demo ...
. The fossil skull was from a three-year-old
bipedal
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' ...
primate (nicknamed
Taung Child
The Taung Child (or Taung Baby) is the fossilised skull of a young ''Australopithecus africanus''. It was discovered in 1924 by quarrymen working for the Northern Lime Company in Taung, South Africa. Raymond Dart described it as a new species ...
) that he named ''
Australopithecus africanus
''Australopithecus africanus'' is an extinct species of australopithecine which lived between about 3.3 and 2.1 million years ago in the Late Pliocene to Early Pleistocene of South Africa. The species has been recovered from Taung, Sterkfonte ...
''. The first report was published in ''
Nature
Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...
'' in February 1925. Dart realised that the fossil contained a number of humanoid features, and so he came to the conclusion that this was an early human ancestor.
Later, Scottish paleontologist
Robert Broom
Robert Broom FRS FRSE (30 November 1866 6 April 1951) was a British- South African doctor and palaeontologist. He qualified as a medical practitioner in 1895 and received his DSc in 1905 from the University of Glasgow.
From 1903 to 1910, he ...
and Dart set out to search for more early hominin specimens, and several more ''A. africanus'' remains from various sites. Initially,
anthropologists
An anthropologist is a person engaged in the practice of anthropology. Anthropology is the study of aspects of humans within past and present societies. Social anthropology, cultural anthropology and philosophical anthropology study the norms and v ...
were largely hostile to the idea that these discoveries were anything but apes, though this changed during the late 1940s.
In 1950, evolutionary biologist
Ernst Walter Mayr
Ernst Walter Mayr (; 5 July 1904 – 3 February 2005) was one of the 20th century's leading evolutionary biologists. He was also a renowned Taxonomy (biology), taxonomist, tropical explorer, ornithologist, Philosophy of biology, philosopher o ...
said that all bipedal apes should be classified into the genus ''Homo'', and considered renaming ''Australopithecus'' to ''Homo transvaalensis''.
However, the contrary view taken by Robinson in 1954, excluding australopiths from ''Homo'', became the prevalent view.
The first australopithecine fossil discovered in eastern Africa was an ''A. boisei'' skull excavated by
Mary Leakey
Mary Douglas Leakey, FBA (née Nicol, 6 February 1913 – 9 December 1996) was a British paleoanthropologist who discovered the first fossilised ''Proconsul
A proconsul was an official of ancient Rome who acted on behalf of a consul. A pro ...
in 1959 in
Olduvai Gorge
The Olduvai Gorge or Oldupai Gorge in Tanzania is one of the most important paleoanthropology, paleoanthropological localities in the world; the many sites exposed by the gorge have proven invaluable in furthering understanding of early human ev ...
,
Tanzania
Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...
. Since then, the Leakey family has continued to excavate the gorge, uncovering further evidence for australopithecines, as well as for ''
Homo habilis
''Homo habilis'' ("handy man") is an extinct species of archaic human from the Early Pleistocene of East and South Africa about 2.31 million years ago to 1.65 million years ago (mya). Upon species description in 1964, ''H. habilis'' was highly ...
'' and ''
Homo erectus
''Homo erectus'' (; meaning "upright man") is an extinct species of archaic human from the Pleistocene, with its earliest occurrence about 2 million years ago. Several human species, such as '' H. heidelbergensis'' and '' H. antecessor' ...
''.
The scientific community took 20 more years to widely accept ''Australopithecus'' as a member of the human family tree.
In 1997, an almost complete ''Australopithecus'' skeleton with skull was found in the
Sterkfontein caves
Sterkfontein (Afrikaans for ''Strong Spring'') is a set of limestone caves of special interest to paleo-anthropologists located in Gauteng province, about northwest of Johannesburg, South Africa in the Muldersdrift area close to the town of K ...
of
Gauteng
Gauteng ( ) is one of the nine provinces of South Africa. The name in Sotho-Tswana languages means 'place of gold'.
Situated on the Highveld, Gauteng is the smallest province by land area in South Africa. Although Gauteng accounts for only ...
, South Africa. It is now called "Little Foot" and it is around 3.7 million years old. It was named ''
Australopithecus prometheus'' which has since been placed within ''A. africanus''. Other fossil remains found in the same cave in 2008 were named ''
Australopithecus sediba
''Australopithecus sediba'' is an extinct species of australopithecine recovered from Malapa Cave, Cradle of Humankind, South Africa. It is known from a partial juvenile skeleton, the holotype MH1, and a partial adult female skeleton, the para ...
'', which lived 1.9 million years ago. ''A. africanus'' probably evolved into ''A. sediba'', which some scientists think may have evolved into ''H. erectus'', though this is heavily disputed.
In 2003, Spanish writer
Camilo José Cela Conde
Camilo José Arcadio Cela Conde, 2nd Marquess of Iria Flavia (born 17 January 1946), is a Spanish writer. He is the son of Nobel Prize in Literature, Nobel Prize winning writer Camilo José Cela and is currently a Professor (highest academic ran ...
and evolutionary biologist
Francisco J. Ayala
Francisco José Ayala Pereda (born March 12, 1934) is a Spanish-American evolutionary biologist, philosopher, and former Catholic priest who was a longtime faculty member at the University of California, Irvine and University of California, Dav ...
proposed resurrecting the genus ''Praeanthropus'' to house ''
Orrorin
''Orrorin tugenensis'' is a postulated early species of Homininae, estimated at and discovered in 2000. It is not confirmed how ''Orrorin'' is related to modern humans. Its discovery was used to argue against the hypothesis that australopitheci ...
'', ''A. afarensis'', ''A. anamensis'', ''A. bahrelghazali'', and ''A. garhi'',
but this genus has been largely dismissed.
Classification
With the apparent emergence of the genera ''
Homo
''Homo'' () is the genus that emerged in the (otherwise extinct) genus ''Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely relate ...
,
Kenyanthropus
''Kenyanthropus'' is a hominin genus identified from the Lomekwi site by Lake Turkana, Kenya, dated to 3.3 to 3.2 million years ago during the Middle Pliocene. It contains one species, ''K. platyops'', but may also include the 2 million year ol ...
'', and ''
Paranthropus
''Paranthropus'' is a genus of extinct hominin which contains two widely accepted species: ''Paranthropus robustus, P. robustus'' and ''P. boisei''. However, the validity of ''Paranthropus'' is contested, and it is sometimes considered to be sy ...
'' in the genus ''Australopithecus,''
taxonomy
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
runs into some difficulty, as the name of species incorporates their genus. According to
cladistics
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...
, groups should not be left
paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
, where it is kept not consisting of a common ancestor and all of its descendants.
Resolving this problem would cause major ramifications in the nomenclature of all descendent species. Possibilities suggested have been to rename ''Homo sapiens'' to ''Australopithecus sapiens'' (or even ''Pan sapiens''), or to move some ''Australopithecus'' species into new genera.
In 2002 and again in 2007, Cele-Conde ''et al.'' suggested that ''A. africanus'' be moved to ''Paranthropus''.
On the basis of craniodental evidence, Strait and Grine (2004) suggest that ''A. anamensis'' and ''A. garhi'' should be assigned to new genera.
It is debated whether or not ''A. bahrelghazali'' should be considered simply a western variant of ''A. afarensis'' instead of a separate species.
Evolution
![Map of the fossil sites of the early hominids (4](https://upload.wikimedia.org/wikipedia/commons/f/fe/Map_of_the_fossil_sites_of_the_early_hominids_%284.4-1M_BP%29.svg)
''A. anamensis'' may have descended from or was closely related to ''
Ardipithecus ramidus
''Ardipithecus ramidus'' is a species of australopithecine from the Afar region of Early Pliocene Ethiopia 4.4 million years ago (mya). ''A. ramidus'', unlike modern hominids, has adaptations for both walking on two legs ( bipedality) and life i ...
''.
''A. anamensis'' shows some similarities to both ''Ar. ramidus'' and ''
Sahelanthropus
''Sahelanthropus tchadensis'' is an extinct species of the Homininae (African apes) dated to about , during the Miocene epoch. The species, and its genus ''Sahelanthropus'', was announced in 2002, based mainly on a partial cranium, nicknamed ''T ...
''.
Australopiths shared several traits with modern apes and humans, and were widespread throughout
Eastern
Eastern may refer to:
Transportation
*China Eastern Airlines, a current Chinese airline based in Shanghai
*Eastern Air, former name of Zambia Skyways
*Eastern Air Lines, a defunct American airline that operated from 1926 to 1991
*Eastern Air Li ...
and
Northern Africa
North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in t ...
by 3.5 million years ago (MYA). The earliest evidence of fundamentally bipedal hominins is a 3.6 MYA
fossil trackway in Laetoli, Tanzania, which bears a remarkable similarity to those of modern humans. The footprints have generally been classified as australopith, as they are the only form of prehuman hominins known to have existed in that region at that time.
According to the
Chimpanzee Genome Project
The Chimpanzee Genome Project was an effort to determine the DNA sequence of the chimpanzee genome. Sequencing began in 2005 and by 2013 twenty-four individual chimpanzees had been sequenced. This project was folded into the Great Ape Genome Pro ...
, the
human–chimpanzee last common ancestor existed about five to six million years ago, assuming a constant rate of mutation. However, hominin species dated to earlier than the date could call this into question.
''
Sahelanthropus tchadensis
''Sahelanthropus tchadensis'' is an extinct species of the Homininae (African apes) dated to about , during the Miocene epoch. The species, and its genus ''Sahelanthropus'', was announced in 2002, based mainly on a partial cranium, nicknamed ''T ...
'', commonly called "''Toumai''", is about seven million years old and ''
Orrorin tugenensis
''Orrorin tugenensis'' is a postulated early species of Homininae, estimated at and discovered in 2000. It is not confirmed how ''Orrorin'' is related to modern humans. Its discovery was used to argue against the hypothesis that australopithecin ...
'' lived at least six million years ago. Since little is known of them, they remain controversial among scientists since the molecular clock in humans has determined that humans and chimpanzees had a genetic split at least a million years later. One theory suggests that the human and chimpanzee lineages diverged somewhat at first, then some populations interbred around one million years after diverging.
Anatomy
![Australopithecus sediba (Fundort Malapa)](https://upload.wikimedia.org/wikipedia/commons/9/98/Australopithecus_sediba_%28Fundort_Malapa%29.jpg)
The brains of most species of ''Australopithecus'' were roughly 35% of the size of a modern human brain with an
endocranial volume average of .
Although this is more than the average endocranial volume of
chimpanzee
The chimpanzee (''Pan troglodytes''), also known as simply the chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. When its close relative th ...
brains at
the earliest australopiths (''A. anamensis'') appear to have been within the chimpanzee range,
whereas some later australopith specimens have a larger endocranial volume than that of some early Homo fossils.
Most species of ''Australopithecus'' were diminutive and gracile, usually standing tall. It is possible that they exhibited a considerable degree of
sexual dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
, males being larger than females.
In modern populations, males are on average a mere 15% larger than females, while in ''Australopithecus'', males could be up to 50% larger than females by some estimates. However, the degree of sexual dimorphism is debated due to the fragmentary nature of australopith remains.
One paper finds that ''A. afarensis'' had a level of dimorphism close to modern humans.
According to A. Zihlman, ''Australopithecus'' body proportions closely resemble those of
bonobo
The bonobo (; ''Pan paniscus''), also historically called the pygmy chimpanzee and less often the dwarf chimpanzee or gracile chimpanzee, is an endangered great ape and one of the two species making up the genus '' Pan,'' the other being the comm ...
s (''Pan paniscus''), leading evolutionary biologist
Jeremy Griffith
Jeremy Griffith (born 1945) is an Australian biologist and author. He first came to public attention for his attempts to find the Tasmanian tiger. He later became noted for his writings on the human condition and theories about human progress, w ...
to suggest that bonobos may be phenotypically similar to ''Australopithecus''. Furthermore, thermoregulatory models suggest that australopiths were fully hair covered, more like chimpanzees and bonobos, and unlike humans.
The fossil record seems to indicate that ''Australopithecus'' is ancestral to ''Homo'' and modern humans. It was once assumed that large brain size had been a precursor to bipedalism, but the discovery of ''Australopithecus'' with a small brain but developed bipedality upset this theory. Nonetheless, it remains a matter of controversy as to how bipedalism first emerged. The advantages of bipedalism were that it left the hands free to grasp objects (e.g., carry food and young), and allowed the eyes to look over tall grasses for possible food sources or predators, but it is also argued that these advantages were not significant enough to cause the emergence of bipedalism. Earlier fossils, such as ''
Orrorin tugenensis
''Orrorin tugenensis'' is a postulated early species of Homininae, estimated at and discovered in 2000. It is not confirmed how ''Orrorin'' is related to modern humans. Its discovery was used to argue against the hypothesis that australopithecin ...
'', indicate bipedalism around six million years ago, around the time of the split between humans and chimpanzees indicated by genetic studies. This suggests that erect, straight-legged walking originated as an adaptation to tree-dwelling. Major changes to the pelvis and feet had already taken place before ''Australopithecus''. It was once thought that humans descended from a
knuckle-walking
Knuckle-walking is a form of quadrupedal walking in which the forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles. Gorillas, bonobos, and chimpanzees use this style o ...
ancestor,
but this is not well-supported.
Australopithecines have thirty-two teeth, like modern humans. Their molars were parallel, like those of great apes, and they had a slight pre-canine gap (diastema). Their canines were smaller, like modern humans, and with the teeth less interlocked than in previous hominins. In fact, in some australopithecines, the canines are shaped more like incisors.
[Kay, R.F., 1985, 'DENTAL EVIDENCE FOR THE DIET OF ''AUSTRALOPITHECUS''', '']Annual Review of Anthropology
The ''Annual Review of Anthropology'' is an academic journal that publishes review articles of significant developments in anthropology and its subfields. First published by Stanford University Press in 1959 under the name the ''Biennial Review of ...
'', 14, pp. 315-341. The molars of ''Australopithicus'' fit together in much the same way those of humans do, with low crowns and four low, rounded cusps used for crushing. They have cutting edges on the crests.
However, australopiths generally evolved a larger postcanine dentition with thicker enamel.
Australopiths in general had thick
enamel, like ''Homo'', while other great apes have markedly thinner enamel.
Robust australopiths wore their molar surfaces down flat, unlike the more gracile species, who kept their crests.
Diet
''Australopithecus'' species are thought to have eaten mainly fruit, vegetables, and tubers, and perhaps easy-to-catch animals such as small lizards. Much research has focused on a comparison between the South African species ''A. africanus'' and ''Paranthropus robustus''. Early analyses of
dental microwear Dental microwear analysis is a method to infer diet and behavior in extinct animals, especially in fossil specimens. Typically, the patterns of pits and scratches on the occlusal or buccal surface of the enamel are compared with patterns observed ...
in these two species showed, compared to ''P. robustus'', ''A. africanus'' had fewer microwear features and more scratches as opposed to pits on its molar wear facets.
Microwear patterns on the cheek teeth of ''A. afarensis'' and ''A. anamensis'' indicate that ''A. afarensis'' predominantly ate fruits and leaves, whereas ''A. anamensis'' included grasses and seeds (in addition to fruits and leaves). The thickening of enamel in australopiths may have been a response to eating more ground-bound foods such as tubers, nuts, and cereal grains with gritty dirt and other small particulates which would wear away enamel. Gracile australopiths had larger incisors, which indicates tearing food was important, perhaps eating scavenged meat. Nonetheless, the wearing patterns on the teeth support a largely herbivorous diet.
In 1992, trace-element studies of the strontium/calcium ratios in robust australopith fossils suggested the possibility of animal consumption, as they did in 1994 using stable carbon isotopic analysis. In 2005, fossil animal bones with butchery marks dating to 2.6 million years old were found at the site of
Gona, Ethiopia
Gona is an archaeological site in the Afar Triangle of Ethiopia located in the Ethiopian Lowlands. The site, near the Middle Awash and Hadar regions, is primarily known for paleoanthropological study, including excavations of Late Miocene an ...
. This implies meat consumption by at least one of three species of hominins occurring around that time: ''A. africanus'', ''A. garhi'', and/or ''P. aethiopicus''. In 2010, fossils of butchered animal bones dated 3.4 million years old were found in Ethiopia, close to regions where australopith fossils were found.
Robust australopithecines (''Paranthropus'') had larger cheek teeth than gracile australopiths, possibly because robust australopithecines had more tough, fibrous plant material in their diets, whereas gracile australopiths ate more hard and brittle foods.
However, such divergence in chewing adaptations may instead have been a response to fallback food availability. In leaner times, robust and gracile australopithecines may have turned to different low-quality foods (fibrous plants for the former, and hard food for the latter), but in more bountiful times, they had more variable and overlapping diets.
In a 1979 preliminary microwear study of ''Australopithecus'' fossil teeth, anthropologist Alan Walker theorized that robust australopiths ate predominantly fruit (
frugivory
A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance an ...
).
A study in 2018 found
non-carious cervical lesions
Non-carious cervical lesions (NCCLs) are a group of lesions that are characterised by a loss of hard dental tissue at the cementoenamel junction (CEJ) region at the neck of the tooth, without the action of microorganisms or inflammatory processe ...
, caused by
acid erosion
Acid erosion is a type of tooth wear. It is defined as the irreversible loss of tooth structure due to chemical dissolution by acids not of bacterial origin. Dental erosion is the most common chronic condition of children ages 5–17, althou ...
, on the teeth of ''
A. africanus'', probably caused by consumption of acidic fruit.
Technology
It was once thought that ''Australopithecus'' could not produce tools like ''Homo'', but the discovery of ''
A. garhi
''Australopithecus garhi'' is a species of australopithecine from the Bouri Formation in the Afar Region of Ethiopia 2.6–2.5 million years ago (mya) during the Early Pleistocene. The first remains were described in 1999 based on several skele ...
'' associated with large mammal bones bearing evidence of processing by stone tools showed this to not have been the case.
Discovered in 1994, this was the oldest evidence of manufacturing at the time until the 2010 discovery of cut marks dating to 3.4 mya attributed to ''A. afarensis'', and the 2015 discovery of the
Lomekwi
Lomekwi 3 is the name of an archaeological site in Kenya where ancient stone tools have been discovered dating to 3.3 million years ago, which make them the oldest ever found.
Discovery
In July 2011, a team of archeologists led by Sonia Harman ...
culture from Lake Turkana dating to 3.3 mya possibly attributed to ''
Kenyanthropus
''Kenyanthropus'' is a hominin genus identified from the Lomekwi site by Lake Turkana, Kenya, dated to 3.3 to 3.2 million years ago during the Middle Pliocene. It contains one species, ''K. platyops'', but may also include the 2 million year ol ...
''. More stone tools dating to about 2.6 mya in
Ledi-Geraru
Ledi-Geraru is a paleoanthropological research area in Mille district, Afar Region, northeastern Ethiopia, along the Ledi and Geraru rivers (two left tributaries of the Awash, south of the Mille river). It stretches for about 50 km, lo ...
in the Afar Region were found in 2019, though these may be attributed to ''Homo''.
In January 2009, four fossils were discovered through the efforts of the Dikika Research Project working in the Lower Awash Valley in north central Ethiopia. Two of the fossils displayed traces of cut marks (DIK-55-2, a right rib fragment of a large ungulate & DIK-55-3, a femur shaft fragment of a young bovid). Research team members stated that fossilization dated after the formation of cut marks, evidence proved by the Secondary electron imaging (SEI) and energy dispersive X-ray (EDX) spectrometry data. Through the optical and environmental scanning electron microscopy (ESEM) observations, the research team also claimed that they could limit the possibility of trampling and biochemical causes, and attributed the cut marks to the effect of cutting and percussion, which indicating the use of stone tools. Considering the contemporaneity and the discovery of ''
Australopithecus afarensis
''Australopithecus afarensis'' is an extinct species of australopithecine which lived from about 3.9–2.9 million years ago (mya) in the Pliocene of East Africa. The first fossils were discovered in the 1930s, but major fossil finds would not ...
'' specimen on the same site (e.g.
DIK-1-1
Selam (DIK-1/1) is the fossilized skull and other skeletal remains of a three-year-old ''Australopithecus afarensis'' female hominin, whose bones were first found in Dikika, Ethiopia in 2000 and recovered over the following years. Although she h ...
), most of the paleoanthropologists attributed this behavior to ''Australopithecus afarensis''.
In 2015, another research team published a paper stating that the ability of tool use of ''Australopithecus afarensis'' could be confirmed by its
trabecular bone
A trabecula (plural trabeculae, from Latin for "small beam") is a small, often microscopic, tissue element in the form of a small beam, strut or rod that supports or anchors a framework of parts within a body or organ. A trabecula generally has ...
pattern. This research team argued that there had been too much dependence on the examination of external morphology in the study of
paleoanthropology
Paleoanthropology or paleo-anthropology is a branch of paleontology and anthropology which seeks to understand the early development of anatomically modern humans, a process known as hominization, through the reconstruction of evolutionary kinship ...
and that sometimes evidence from external morphology could be ambiguous. Some traits could be ancestral and no longer serve a purpose. In the case of the trabecular bone, it changes through life according to mechanical loading, therefore it could be a good hand morphology reference for ''Australopithecus afarensis'' on the matter of appropriate hand postures for tool use. After the comparison of Hylobatids,
Pongo,
Gorilla
Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...
, Pan, recent ''
H. sapiens'' and early ''H. sapiens'', this team concluded that a complete suite of derived later Homo-like hand morphology was not necessary for using tools, and the trabecular orientation of ''Australopithecus afarensis''
metacarpals
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeleton, skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpa ...
was clearly shaped by the use of tools.
There are debates, however, regarding whether the ''Australopithecus afarensis'' was simply a tool user or a craftsman. One research team in 2017 claimed that the ''Australopithecus afarensis'' did not have a forceful and precise grip that was adequate for tool making. This team focused their study on the 5th ray of ''Australopithecus afarensis'', a trait which is important for the ability of hand to grip. The morphology of hamate-metacarpal V joint (CMC-V) could determine the flexibility of the 5th ray and the formation of a powerful grip, through the simulation of musculoskeletal models (with the presence of certain technical and informational limitations), evidence showed the pulp of the 5th ray did not provide the necessary conditions for the maintenance of a large-sized object, thus making the hypothesis of tool maker ''Australopithecus afarensis'' questionable.
Notable specimens
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KT-12/H1, an ''A. bahrelghazali'' mandibular fragment, discovered 1995 in Sahara, Chad
*
AL 129-1, an ''A. afarensis'' knee joint, discovered 1973 in Hadar, Ethiopia
*
Karabo, a juvenile male ''A. sediba'', discovered in South Africa
*
Laetoli footprints
Laetoli is a pre-historic site located in Enduleni ward of Ngorongoro District in Arusha Region, Tanzania. The site is dated to the Plio-Pleistocene and famous for its Hominina footprints, preserved in volcanic ash. The site of the Laetoli foo ...
, preserved hominin footprints in Tanzania
*
Lucy
Lucy is an English feminine given name derived from the Latin masculine given name Lucius with the meaning ''as of light'' (''born at dawn or daylight'', maybe also ''shiny'', or ''of light complexion''). Alternative spellings are Luci, Luce, Lu ...
, a 40%-complete skeleton of a female ''A. afarensis'', discovered 1974 in Hadar, Ethiopia
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Selam, remains of a three-year-old ''A. afarensis'' female, discovered in Dikika, Ethiopia
*
STS 5 (Mrs. Ples), the most complete skull of an ''A. africanus'' ever found in South Africa
*
STS 14
STS 14 is a fossilized partial skeleton of the species ''Australopithecus africanus''. It was discovered at Sterkfontein, South Africa by Robert Broom and John T. Robinson in August 1947, and is estimated to be about 2.5 million years old.
Some ...
, remains of an ''A. africanus'', discovered 1947 in Sterkfontein, South Africa
*
STS 71
STS 71 is a fossilized skull of the species ''Australopithecus africanus''. It was discovered in Sterkfontein, South Africa by Robert Broom in 1947. In 1972 John Wallace connected STS 71 with STS 36, a lower jaw found in the same layer, by match ...
, skull of an ''A. africanus'', discovered 1947 in Sterkfontein, South Africa
*
Taung Child
The Taung Child (or Taung Baby) is the fossilised skull of a young ''Australopithecus africanus''. It was discovered in 1924 by quarrymen working for the Northern Lime Company in Taung, South Africa. Raymond Dart described it as a new species ...
, skull of a young ''A. africanus'', discovered 1924 in Taung, South Africa
Gallery
Plaque marking the discovery of Australopithecus in Tanzania.jpg, The spot where the first ''Australopithecus boisei'' was discovered in Tanzania
Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...
.
Mrs Ples.jpg, Original skull of Mrs. Ples
__NOTOC__
Mrs. Ples is the popular nickname for the most complete skull of an ''Australopithecus africanus'' ever found in South Africa. Many ''Australopithecus'' fossils have been found near Sterkfontein, about northwest of Johannesburg, in a r ...
, a female ''A. africanus''
Taung child - Skin and Muscles.png, Taung Child by Cicero Moraes, Arc-Team, Antrocom NPO, Museum of the University of Padua
The University of Padua ( it, Università degli Studi di Padova, UNIPD) is an Italian university located in the city of Padua, region of Veneto, northern Italy. The University of Padua was founded in 1222 by a group of students and teachers from B ...
.
Lucy blackbg.jpg, Cast of the skeleton of Lucy, an ''A. afarensis''
Australopithecus africanus - Cast of taung child.jpg, Skull of the Taung child
See also
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Aramis, Ethiopia
Aramis is a village and archaeological site in north-eastern Ethiopia, where remains of ''Australopithecus'' and ''Ardipithecus'' (''Ardipithecus ramidus'') have been found. The village is located in Administrative Zone 5 of the Afar Region, which ...
* ''
Ardipithecus
''Ardipithecus'' is a genus of an extinct hominine that lived during the Late Miocene and Early Pliocene epochs in the Afar Depression, Ethiopia. Originally described as one of the earliest ancestors of humans after they diverged from the chimpa ...
''
*
Chimpanzee–human last common ancestor
The chimpanzee–human last common ancestor (CHLCA) is the last common ancestor shared by the extant ''Homo'' (human) and '' Pan'' (chimpanzee and bonobo) genera of Hominini. Due to complex hybrid speciation, it is not currently possible to give ...
* ''
Homo habilis
''Homo habilis'' ("handy man") is an extinct species of archaic human from the Early Pleistocene of East and South Africa about 2.31 million years ago to 1.65 million years ago (mya). Upon species description in 1964, ''H. habilis'' was highly ...
''
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LD 350-1
LD 350-1 is the earliest known specimen of the genus ''Homo'', dating to 2.8–2.75 million years ago (mya), found in the Ledi-Geraru site in the Afar Region of Ethiopia. The specimen was discovered in silts above the Gurumaha Tuff section of the ...
*
Little Foot
"Little Foot" (Stw 573) is the nickname given to a nearly complete Australopithecus fossil skeleton found in 1994–1998 in the cave system of Sterkfontein, South Africa.
Originally nicknamed "little foot" in 1995 when four ankle bones in a mu ...
*
List of fossil sites
This list of fossil sites is a worldwide list of localities known well for the presence of fossils. Some entries in this list are notable for a single, unique find, while others are notable for the large number of fossils found there. Many of t ...
(with link directory)
*
List of human evolution fossils
The following tables give an overview of notable finds of Hominini, hominin fossils and Skeleton, remains relating to human evolution, beginning with the formation of the tribe Hominini (the divergence of the Chimpanzee–human last common ancest ...
(with images)
References
Sources
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Further reading
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External links
Metadata and Virtual Models of Australopithecus Fossils on NESPOSThe Age of Australopithecus- Interactive Map of the Evolution of Australopithecus
Human Timeline (Interactive)–
Smithsonian,
National Museum of Natural History
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...
(August 2016).
{{Authority control
Prehistoric primate genera
Pliocene primates
Pliocene mammals of Africa
Pleistocene mammals of Africa
Transitional fossils
Piacenzian first appearances
Fossil taxa described in 1925
Taxa named by Raymond Dart