Australopithecus
Overview
Australopithecus is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of hominids that is now extinct. From the evidence gathered by palaeontologists
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...

 and archaeologists
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

, it appears that the Australopithecus genus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct 2 million years ago. During this time period various forms of australopiths existed, including Australopithecus anamensis
Australopithecus anamensis
Australopithecus anamensis is a stem-human species that lived approximately four million years ago. Nearly one hundred fossil specimens are known from Kenya and Ethiopia, representing over 20 individuals.- Discovery :...

, A. afarensis
Australopithecus afarensis
Australopithecus afarensis is an extinct hominid that lived between 3.9 and 2.9 million years ago. A. afarensis was slenderly built, like the younger Australopithecus africanus. It is thought that A...

, A. sediba
Australopithecus sediba
Australopithecus sediba is a species of Australopithecus of the early Pleistocene, identified based on fossil remains dated to about 2 million years ago....

, and A. africanus
Australopithecus africanus
Australopithecus africanus was an early hominid, an australopithecine, who lived between 2–3 million years ago in the Pliocene. In common with the older Australopithecus afarensis, A. africanus was slenderly built, or gracile, and was thought to have been a direct ancestor of modern humans. Fossil...

.
Encyclopedia
Australopithecus is a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of hominids that is now extinct. From the evidence gathered by palaeontologists
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...

 and archaeologists
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

, it appears that the Australopithecus genus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct 2 million years ago. During this time period various forms of australopiths existed, including Australopithecus anamensis
Australopithecus anamensis
Australopithecus anamensis is a stem-human species that lived approximately four million years ago. Nearly one hundred fossil specimens are known from Kenya and Ethiopia, representing over 20 individuals.- Discovery :...

, A. afarensis
Australopithecus afarensis
Australopithecus afarensis is an extinct hominid that lived between 3.9 and 2.9 million years ago. A. afarensis was slenderly built, like the younger Australopithecus africanus. It is thought that A...

, A. sediba
Australopithecus sediba
Australopithecus sediba is a species of Australopithecus of the early Pleistocene, identified based on fossil remains dated to about 2 million years ago....

, and A. africanus
Australopithecus africanus
Australopithecus africanus was an early hominid, an australopithecine, who lived between 2–3 million years ago in the Pliocene. In common with the older Australopithecus afarensis, A. africanus was slenderly built, or gracile, and was thought to have been a direct ancestor of modern humans. Fossil...

. There is still some debate amongst academics whether certain African hominid species of this time, such as A. robustus and A. boisei, constitute members of the same genus; if so, they would be considered to be robust australopiths whilst the others would be considered gracile australopiths. However, if these species do indeed constitute their own genus, then they may be given their own name, the Paranthropus
Paranthropus
The robust australopithecines, members of the extinct hominin genus Paranthropus , were bipedal hominids that probably descended from the gracile australopithecine hominids...

.

It is widely held by archaeologists and palaeontologists that the australopiths played a significant part in human evolution
Human evolution
Human evolution refers to the evolutionary history of the genus Homo, including the emergence of Homo sapiens as a distinct species and as a unique category of hominids and mammals...

, and it was one of the australopith species that eventually evolved into the Homo
Homo
Homo may refer to:*the Greek prefix ὅμο-, meaning "the same"*the Latin for man, human being*Homo, the taxonomical genus including modern humans...

genus in Africa around 2 million years ago, which contained within it species like Homo habilis
Homo habilis
Homo habilis is a species of the genus Homo, which lived from approximately at the beginning of the Pleistocene period. The discovery and description of this species is credited to both Mary and Louis Leakey, who found fossils in Tanzania, East Africa, between 1962 and 1964. Homo habilis Homo...

, H. ergaster
Homo ergaster
Homo ergaster is an extinct chronospecies of Homo that lived in eastern and southern Africa during the early Pleistocene, about 2.5–1.7 million years ago.There is still disagreement on the subject of the classification, ancestry, and progeny of H...

and eventually the modern human species, H. sapiens sapiens.

Evolution

Gracile australopiths shared several traits with modern apes and humans, and were widespread throughout Eastern and Northern Africa around 3.5 million years ago. The earliest evidence of fundamentally bipedal hominids can be observed at the site of Laetoli
Laetoli
Laetoli is a site in Tanzania, dated to the Plio-Pleistocene and famous for its hominin footprints, preserved in volcanic ash . The site of the Laetoli footprints is located 45 km south of Olduvai gorge.-Date:...

 in Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

. This site contains hominid footprints that are remarkably similar to those of modern humans and have been dated to as old as 3.6 million years. Until recently, the footprints have generally been classified as australopith because that had been the only form of pre-human known to have existed in that region at that time; however, some scholars have considered reassigning them to a yet unidentified very early species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of the genus Homo.
Australopithecus anamensis
Australopithecus anamensis
Australopithecus anamensis is a stem-human species that lived approximately four million years ago. Nearly one hundred fossil specimens are known from Kenya and Ethiopia, representing over 20 individuals.- Discovery :...

, Australopithecus afarensis
Australopithecus afarensis
Australopithecus afarensis is an extinct hominid that lived between 3.9 and 2.9 million years ago. A. afarensis was slenderly built, like the younger Australopithecus africanus. It is thought that A...

and Australopithecus africanus
Australopithecus africanus
Australopithecus africanus was an early hominid, an australopithecine, who lived between 2–3 million years ago in the Pliocene. In common with the older Australopithecus afarensis, A. africanus was slenderly built, or gracile, and was thought to have been a direct ancestor of modern humans. Fossil...

are among the most famous of the extinct hominins. A. africanus used to be regarded as ancestral to the genus Homo (in particular Homo erectus
Homo erectus
Homo erectus is an extinct species of hominid that lived from the end of the Pliocene epoch to the later Pleistocene, about . The species originated in Africa and spread as far as India, China and Java. There is still disagreement on the subject of the classification, ancestry, and progeny of H...

). However, fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s assigned to the genus Homo have been found that are older than A. africanus. Thus, the genus Homo either split off from the genus Australopithecus at an earlier date (the latest common ancestor being A. afarensis or an even earlier form, possibly Kenyanthropus platyops
Kenyanthropus platyops
Kenyanthropus platyops is a 3.5 to 3.2 million year old hominin fossil that was discovered in Lake Turkana, Kenya in 1999 by Justus Erus, who was part of Meave Leakey's team...

), or both developed from a yet possibly unknown common ancestor independently.

According to the Chimpanzee Genome Project
Chimpanzee Genome Project
The Chimpanzee Genome Project is an effort to determine the DNA sequence of the Chimpanzee genome. It is expected that by comparing the genomes of humans and other apes, it will be possible to better understand what makes humans distinct from other species....

, both human (Ardipithecus
Ardipithecus
Ardipithecus is a very early hominin genus. Two species are described in the literature: A. ramidus, which lived about 4.4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago ....

, Australopithecus and Homo) and chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...

 (Pan troglodytes and Pan paniscus) lineages diverged from a common ancestor about 5 to 6 million years ago, if we assume a constant rate of evolution. It is theoretically more likely for evolution to happen more slowly, as opposed to more quickly, from the date suggested by a gene clock (the result of which is given as a "youngest common ancestor", i.e., the latest possible date of diversion.) However, hominins discovered more recently are somewhat older than the molecular clock
Molecular clock
The molecular clock is a technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged. It is used to estimate the time of occurrence of events called speciation or radiation...

 would theorize. Sahelanthropus tchadensis
Sahelanthropus tchadensis
Sahelanthropus tchadensis is an extinct hominid species that is dated to about . Whether it can be regarded as part of the Hominina tree is unclear; there are arguments both supporting and rejecting it...

, commonly called "Toumai" is about 7 million years old and Orrorin tugenensis
Orrorin tugenensis
Orrorin tugenensis is considered to be the second-oldest known hominin ancestor that is possibly related to modern humans, and it is the only species classified in genus Orrorin...

lived at least 6 million years ago. Since little is known of them, they remain controversial among scientists since the molecular clock
Molecular clock
The molecular clock is a technique in molecular evolution that uses fossil constraints and rates of molecular change to deduce the time in geologic history when two species or other taxa diverged. It is used to estimate the time of occurrence of events called speciation or radiation...

 in humans has determined that humans and chimpanzees had an evolutionary 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.

Morphology

The brains of most species of Australopithecus were roughly 35% of the size of that of a modern human brain. Most species of Australopithecus were diminutive and gracile, usually standing between 1.2 metre tall. In several variations of Australopithecus there is a considerable degree of sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...

, in this case males being larger than females. Modern hominids do not appear to display sexual dimorphism to the same degree — particularly, modern humans display a low degree of sexual dimorphism, with males being only 15% larger than females, on average. In Australopithecus, however, males can be up to 50% larger than females. New research suggests that sexual dimorphism may be less pronounced than this, but there is still debate on the subject.

Species variations

Although opinions differ as to whether the species aethiopicus, boisei and robustus should be included within the genus Australopithecus, the current consensus in the scientific community is that they should be placed in a distinct genus, Paranthropus
Paranthropus
The robust australopithecines, members of the extinct hominin genus Paranthropus , were bipedal hominids that probably descended from the gracile australopithecine hominids...

, which is believed to have developed from the ancestral Australopithecus line. Up until the last half-decade, the majority of the scientific community included all the species shown in the box at the top of this article in a single genus. However, Paranthropus was morphologically
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 distinct from Australopithecus, and its specialized morphology also implies that its behavior was quite different from that of its ancestors.

Evolutionary role

The fossil record seems to indicate that Australopithecus is the common ancestor of the distinct group of hominids, now called Paranthropus
Paranthropus
The robust australopithecines, members of the extinct hominin genus Paranthropus , were bipedal hominids that probably descended from the gracile australopithecine hominids...

(the "robust australopiths"), and most likely the genus Homo which includes modern humans. Although the intelligence of these early hominids was likely no more sophisticated than modern apes, the bipedal stature is the key evidence which distinguishes the group from previous primates who are quadrupeds. The morphology of Australopithecus upsets what scientists previously believed, namely, that large brains preceded bipedalism. If A. afarensis was the definite hominid which left the footprints at Laetoli
Laetoli
Laetoli is a site in Tanzania, dated to the Plio-Pleistocene and famous for its hominin footprints, preserved in volcanic ash . The site of the Laetoli footprints is located 45 km south of Olduvai gorge.-Date:...

, it strengthens the notion that A. afarensis had a small brain but was a biped. Fossil evidence such as this has made it clear that bipedalism far predated large brains. However, it remains a matter of controversy how bipedalism first evolved millions of years ago (several concepts are still being studied). The advantages of bipedalism allowed hands to be free for grasping objects (e.g. carrying food and young), and allowed the eyes to look over tall grasses for possible food sources or predators. However, many anthropologists argue that these advantages were not large enough to cause the evolution of bipedalism.
A recent study of primate evolution and morphology noted that all apes, both modern and fossil, show skeletal adaptations to upright posture of the trunk, and that fossils such as Orrorin tugenensis
Orrorin tugenensis
Orrorin tugenensis is considered to be the second-oldest known hominin ancestor that is possibly related to modern humans, and it is the only species classified in genus Orrorin...

indicate bipedalism around 6 million years ago, around the time of the split between humans and chimpanzees indicated by genetic studies. This suggested that upright, straight-legged walking originally evolved as an adaptation to tree-dwelling. Studies of modern orangutan
Orangutan
Orangutans are the only exclusively Asian genus of extant great ape. The largest living arboreal animals, they have proportionally longer arms than the other, more terrestrial, great apes. They are among the most intelligent primates and use a variety of sophisticated tools, also making sleeping...

s in Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

 showed that these apes use four legs when walking on large stable branches, swing underneath slightly smaller branches, but are bipedal and keep their legs very straight when walking on multiple small flexible branches under 4 cm diameter, while also using their arms for balance and additional support. This enables them to get nearer to the edge of the tree canopy to get fruit or cross to another tree.

It is suggested that the ancestors of gorilla
Gorilla
Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...

s and chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...

s became more specialised in climbing vertical tree trunks, using a bent hip and bent knee posture which matches the knuckle-walking posture they use for ground travel. This was due to climate changes around 11 to 12 million years ago that affected forests in East and Central Africa so that there were periods when openings prevented travel through the tree canopy, and at these times ancestral hominids could have adapted the upright walking behaviour for ground travel. Humans are closely related to these apes, and share features including wrist bones apparently strengthened for knuckle-walking
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....

. However, the view that human ancestors were knuckle-walkers is now questioned since the anatomy and biomechanics of knuckle-walking in chimpanzees and gorillas are different suggesting this ability evolved independently after the last common ancestor with the human lineage. Further comparative analysis with other primates suggests these wrist bone adaptations support a palm based tree walking.

Radical changes in morphology took place before gracile australopiths evolved; the pelvis structure and feet are very similar to modern humans. The teeth have small canines, but australopiths generally evolved a larger post-canine dentition with thicker enamel.

Most species of Australopithecus were not any more adept at tool use than modern non-human primates, yet modern African apes, chimpanzees, and most recently gorilla
Gorilla
Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...

s, have been known to use simple tools (i.e. cracking open nuts with stones and using long sticks to dig for termite
Termite
Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...

s in mounds), and chimpanzees have been observed using spears (not thrown) for hunting.

However, some have argued that A. garhi
Australopithecus garhi
Australopithecus garhi is a gracile australopithecine species whose fossils were discovered in 1996 by a research team led by Ethiopian paleontologist Berhane Asfaw and Tim White, an American paleontologist. The hominin remains are believed to be a human ancestor species and the final missing link...

used stone tools due to a loose association of this species and butchered animal remains.

Diet

In a 1979 preliminary microwear study of Australopithecus fossil teeth, anthropologist Alan Walker theorized that robust australopiths were largely frugivorous. Australopithecus mainly ate fruit, vegetables, and tubers. Much research has focused on a comparison between the South African species Australopithecus africanus and Paranthropus robustus. Early analyses of dental microwear in these two species showed that compared to Paranthropus robustus, Australopithecus africanus had fewer microwear features and more scratches as opposed to pits on its molar wear facets. These observations have been interpreted as evidence that Paranthropus robustus may have fed on hard and brittle foods like some nuts and seeds. More recently new analyses based on three-dimensional renderings of wear facets have confirmed earlier work but have also suggested that Paranthropus robustus ate hard foods primarily as a fallback resource while Australopithecus africanus ate more mechanically tough foods.

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.

History of study

The first australopithecine to be discovered and documented was a fossil of a three year old Australopithecus africanus
Australopithecus africanus
Australopithecus africanus was an early hominid, an australopithecine, who lived between 2–3 million years ago in the Pliocene. In common with the older Australopithecus afarensis, A. africanus was slenderly built, or gracile, and was thought to have been a direct ancestor of modern humans. Fossil...

which was discovered in a lime quarry by workers at Taung, South Africa. The specimen was studied by the Australian anatomist Raymond Dart
Raymond Dart
Raymond Arthur Dart 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 hominid closely related to humans, at Taung in the North of South Africa in the province...

, who was then working at the University of the Witwatersrand
University of the Witwatersrand
The University of the Witwatersrand, Johannesburg is a South African university situated in the northern areas of central Johannesburg. It is more commonly known as Wits University...

 in Johannesburg
Johannesburg
Johannesburg also known as Jozi, Jo'burg or Egoli, is the largest city in South Africa, by population. Johannesburg is the provincial capital of Gauteng, the wealthiest province in South Africa, having the largest economy of any metropolitan region in Sub-Saharan Africa...

 who published his findings in Nature magazine in February 1925. Dart realised that the fossil contained a number of humanoid features, and so came to the conclusion that this was an early ancestor of humans. Ten years later, he and the Scottish paleontologist Robert Broom
Robert Broom
Professor Robert Broom was a Scottish South African doctor and paleontologist. He qualified as a medical practitioner in 1895 and received his DSc in 1905 from the University of Glasgow...

, set about to search for more early hominin specimens, and at several sites they found further A. africanus remains as well as fossils of a species which Broom named Paranthropus (which would now be recognised as Paranthropus robustus
Paranthropus robustus
Paranthropus robustus was originally discovered in Southern Africa in 1938. The development of P. robustus, namely in cranial features, seemed to be aimed in the direction of a "heavy-chewing complex"...

). Initially, anthropologists
Anthropology
Anthropology is the study of humanity. It has origins in the humanities, the natural sciences, and the social sciences. The term "anthropology" is from the Greek anthrōpos , "man", understood to mean mankind or humanity, and -logia , "discourse" or "study", and was first used in 1501 by German...

 were largely hostile to the idea that these discoveries were anything but apes, though this changed during the latter years of the 1940s.

The first australopithecine to be discovered in eastern Africa was a skull belonging to an Australopithecus boisei that was excavated in 1959 in the Olduvai Gorge
Olduvai Gorge
The Olduvai Gorge is a steep-sided ravine in the Great Rift Valley that stretches through eastern Africa. It is in the eastern Serengeti Plains in northern Tanzania and is about long. It is located 45 km from the Laetoli archaeological site...

 in Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

 by Mary Leakey
Mary Leakey
Mary Leakey was a British archaeologist and anthropologist, who discovered the first skull of a fossil ape on Rusinga Island and also a noted robust Australopithecine called Zinjanthropus at Olduvai. For much of her career she worked together with her husband, Louis Leakey, in Olduvai Gorge,...

. Since then, the Leakey family have continued to excavate the gorge, uncovering further evidence for australopithecines as well as for Homo habilis
Homo habilis
Homo habilis is a species of the genus Homo, which lived from approximately at the beginning of the Pleistocene period. The discovery and description of this species is credited to both Mary and Louis Leakey, who found fossils in Tanzania, East Africa, between 1962 and 1964. Homo habilis Homo...

and Homo erectus
Homo erectus
Homo erectus is an extinct species of hominid that lived from the end of the Pliocene epoch to the later Pleistocene, about . The species originated in Africa and spread as far as India, China and Java. There is still disagreement on the subject of the classification, ancestry, and progeny of H...

.

Scientists have recently discovered a new australopithecine in South Africa. The fossils of "Australopithecus sediba
Australopithecus sediba
Australopithecus sediba is a species of Australopithecus of the early Pleistocene, identified based on fossil remains dated to about 2 million years ago....

", which lived 1.9 million years ago, were found in Malapa cave in South Africa. It is thought "Australopithecus africanus
Australopithecus africanus
Australopithecus africanus was an early hominid, an australopithecine, who lived between 2–3 million years ago in the Pliocene. In common with the older Australopithecus afarensis, A. africanus was slenderly built, or gracile, and was thought to have been a direct ancestor of modern humans. Fossil...

" probably gave rise to "Australopithecus sediba
Australopithecus sediba
Australopithecus sediba is a species of Australopithecus of the early Pleistocene, identified based on fossil remains dated to about 2 million years ago....

", which some scientists think possibly evolved into "Homo erectus
Homo erectus
Homo erectus is an extinct species of hominid that lived from the end of the Pliocene epoch to the later Pleistocene, about . The species originated in Africa and spread as far as India, China and Java. There is still disagreement on the subject of the classification, ancestry, and progeny of H...

".

Molecular evolution point of view

According to molecular evolution principles Human evolutionary genetics
Human evolutionary genetics
Human evolutionary genetics studies how one human genome differs from the other, the evolutionary past that gave rise to it, and its current effects. Differences between genomes have anthropological, medical and forensic implications and applications...

 ( Jobling, Hurles and Tyler-Smith, 2004), the most recent common ancestor of humans and chimpanzees had as much pre-human traits as chimp-like traits. In other words, progressing along the chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...

 line means losing some human-like traits and gaining chimpanzee traits, whereas progressing along the Human
Human
Humans are the only living species in the Homo genus...

 line means losing some chimp-like traits and gaining human traits. A fossil close to the last common ancestor is thus difficult to place in a precise chimp or human lineage because it has not accumulated enough differences since the two lines have diverged. For instance, the most recent Paranthropus
Paranthropus
The robust australopithecines, members of the extinct hominin genus Paranthropus , were bipedal hominids that probably descended from the gracile australopithecine hominids...

 fossils are 1.2 million years old, fairly recent compared to the time since the divergence of humans and gorillas (7-9 mya), therefore many of the paranthropus traits are very much like gorillas (see Homininae
Homininae
Homininae is a subfamily of Hominidae, which includes humans, gorillas and chimpanzees, and some extinct relatives; it comprises all those hominids, such as Australopithecus, that arose after the split from orangutans . Our family tree, which has 3 main branches leading to chimpanzees, humans and...

). In contrast, it is more difficult to place a 3 or 4 million years old australopithecines fossil in the chimp or human lineages. A. africanus
A. africanus
A. africanus is an abbreviation of a species name. In binomial nomenclature the name of a species is always the name of the genus to which the species belongs, followed by the species name . In A. africanus the genus name has been abbreviated to A. and the species has been spelled out in full...

 seem to be close to the human lineage, whereas A. afarensis are closer to the chimp lineage, with the exception of Selam (3.3Mya) who has been placed in A.afarensis, but has more human traits than Lucy (3.2Mya) for instance, and would better be placed in A. africanus
A. africanus
A. africanus is an abbreviation of a species name. In binomial nomenclature the name of a species is always the name of the genus to which the species belongs, followed by the species name . In A. africanus the genus name has been abbreviated to A. and the species has been spelled out in full...

.
The mainstream view among paleontologists can be found in this page and in the main "human evolution
Human evolution
Human evolution refers to the evolutionary history of the genus Homo, including the emergence of Homo sapiens as a distinct species and as a unique category of hominids and mammals...

" page, but similar conclusions were reached by at least two other biologists, independently: the author of the “Paranthropus aethiopicus” page of the “Online Biology Dictionary” and Richard Dawkins in his book “The Ancestor's Tale” "According to this theory, chimps and bonobos are descended from Australopithecus Gracile type species while gorillas are descended from Australopithecus Robustus (Parnthropus) type species. These apes were once bipedal but then lost this ability when they were forced back into the semi-forest, presumably by those Australopithecines who eventually became us"; In short, ancestors of chimpanzees are Australopithecus afarensis and ancestors of gorillas are Paranthropus (see tree on Homininae
Homininae
Homininae is a subfamily of Hominidae, which includes humans, gorillas and chimpanzees, and some extinct relatives; it comprises all those hominids, such as Australopithecus, that arose after the split from orangutans . Our family tree, which has 3 main branches leading to chimpanzees, humans and...

).

Notable specimens

  • AL 129-1
    AL 129-1
    AL 129-1 is the fossilized knee joint of the species Australopithecus afarensis. It was discovered in Hadar, Ethiopia by Donald Johanson in November 1973.It is estimated to be 3-3.2 million years old....

  • Karabo
    Australopithecus sediba
    Australopithecus sediba is a species of Australopithecus of the early Pleistocene, identified based on fossil remains dated to about 2 million years ago....

  • Laetoli footprints
    Laetoli
    Laetoli is a site in Tanzania, dated to the Plio-Pleistocene and famous for its hominin footprints, preserved in volcanic ash . The site of the Laetoli footprints is located 45 km south of Olduvai gorge.-Date:...

  • Lucy
    Lucy (Australopithecus)
    Lucy is the common name of AL 288-1, several hundred pieces of bone representing about 40% of the skeleton of an individual Australopithecus afarensis. The specimen was discovered in 1974 at Hadar in the Awash Valley of Ethiopia's Afar Depression. Lucy is estimated to have lived 3.2 million years...

  • Selam
    Selam (Australopithecus)
    Selam is the fossilized skull and other skeletal remains of a 3-year-old Australopithecus afarensis female whose bones were first found in Dikika, Ethiopia in 2000 and recovered over the following years. She is often nicknamed Lucy's baby. The remains have been dated at 3.3 mya, approximately...

  • STS 5 (Mrs. Ples)
    Mrs. Ples
    Mrs. Ples is the popular nickname for the most complete skull of an Australopithecus africanus specimen ever found in South Africa. Many fossils of this species, which are considered to be the distant relatives of all humankind, have been found in the Sterkfontein area, in what has been designated...

  • STS 14
    STS 14
    STS 14 is a fossilized pelvis, vertebral column and fragmentary rib and femur of the species Australopithecus africanus. It was discovered at Sterkfontein, South Africa by Robert Broom in August 1947.It is estimated to be 2.6-2.8 million years old....

  • STS 71
    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...

  • Taung Child
    Taung Child
    The Taung Child — or Taung Baby — is the fossilized skull of a young Australopithecus africanus individual. It was discovered in 1924 by quarrymen working for the Northern Lime Company in Taung, South Africa...


See also

  • Aramis, Ethiopia
    Aramis, Ethiopia
    Aramis is a village and archaeological site in northeastern Ethiopia, where remains of Australopithecus and Ardipithecus have been found...

  • List of fossil sites (with link directory)
  • List of human evolution fossils (with images)
  • Ardipithecus
    Ardipithecus
    Ardipithecus is a very early hominin genus. Two species are described in the literature: A. ramidus, which lived about 4.4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago ....

  • Homo habilis
    Homo habilis
    Homo habilis is a species of the genus Homo, which lived from approximately at the beginning of the Pleistocene period. The discovery and description of this species is credited to both Mary and Louis Leakey, who found fossils in Tanzania, East Africa, between 1962 and 1964. Homo habilis Homo...

  • Pan prior

External links

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