Australopithecus

Last updated

Contents

Australopithecus
Temporal range: Zanclean – Gelasian, 4.5–1.9/1.2 mya
Ꞓ
O
S
D
C
P
T
J
K
Pg
N
↓
Mrs Ples Face.jpg
Mrs. Ples, an Australopithecus africanus specimen
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Hominidae
Subfamily: Homininae
Tribe: Hominini
Subtribe: Australopithecina
Genus:† Australopithecus
R.A. Dart, 1925
Type species
† Australopithecus africanus
Dart, 1925
Species

Classically excluded but cladistically included:

Australopithecus ( /ˌɒstrələˈpɪθɪkəs,-loʊ-/ , OS-trə-lə-PITH-i-kəs, -⁠loh-; [1] from Latin australis 'southern',and Ancient Greek πίθηκος (pithekos) 'ape' [2] ) is a genus of early hominins that existed in Africa during the Pliocene and Early Pleistocene. The genera Homo (which includes modern humans), Paranthropus , and Kenyanthropus evolved from some Australopithecus species. Australopithecus is a member of the subtribe Australopithecina, [3] [4] which sometimes also includes Ardipithecus , [5] though the term "australopithecine" is sometimes used to refer only to members of Australopithecus. Species include A. garhi , A. africanus , A. sediba , A. afarensis, 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. [6] [7]

Furthermore, because e.g. A. africanus is more closely related to for instance humans, or their ancestors at the time, than e.g. A. anamensis and many more Australopithecus branches, Australopithecus cannot be consolidated into a coherent grouping without also including the Homo genus and other genera.

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 [6] [8] [9] [10] [11] [ excessive citations ] at some time between 3 and 2 million years ago. [12]

Australopithecus possessed two of three duplicated genes derived from SRGAP2 roughly 3.4 and 2.4 million years ago ( SRGAP2B and SRGAP2C ), the second of which contributed to the increase in number and migration of neurons in the human brain. [13] [14] 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 and the trapezium and capitate). [15]

Taxonomy

Research history

Taung Child's skull Australopithecus africanus Taung face (University of Zurich).JPG
Taung Child's skull

The first Australopithecus specimen, the type specimen, was discovered in 1924 in a lime quarry by workers at Taung, South Africa. The specimen was studied by the Australian anatomist Raymond Dart, who was then working at the University of the Witwatersrand in Johannesburg. The fossil skull was from a three-year-old bipedal primate (nicknamed Taung Child) that he named Australopithecus africanus . The first report was published in Nature 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. [16] Later, Scottish paleontologist Robert Broom and Dart set out to search for more early hominin specimens, and several more A. africanus remains from various sites. Initially, anthropologists were largely hostile to the idea that these discoveries were anything but apes, though this changed during the late 1940s. [16]

In 1950, evolutionary biologist Ernst Walter Mayr said that all bipedal apes should be classified into the genus Homo, and considered renaming Australopithecus to Homo transvaalensis. [17] However, the contrary view taken by Robinson in 1954, excluding australopiths from Homo, became the prevalent view. [17] The first australopithecine fossil discovered in eastern Africa was an A. boisei skull excavated by Mary Leakey in 1959 in Olduvai Gorge, Tanzania. Since then, the Leakey family has continued to excavate the gorge, uncovering further evidence for australopithecines, as well as for Homo habilis and Homo erectus . [16] 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 of Gauteng, South Africa. It is now called "Little Foot" and it is around 3.7 million years old. It was named Australopithecus prometheus [18] [19] which has since been placed within A. africanus. Other fossil remains found in the same cave in 2008 were named Australopithecus sediba , which lived 1.9 million years ago. A. africanus probably evolved into A. sediba, which some scientists think may have evolved into H. erectus, [20] though this is heavily disputed.

In 2003, Spanish writer Camilo José Cela Conde and evolutionary biologist Francisco J. Ayala proposed resurrecting the genus Praeanthropus to house Orrorin , A. afarensis, A. anamensis, A. bahrelghazali, and A. garhi, [21] but this genus has been largely dismissed. [22]

Classification

With the apparent emergence of the genera Homo, Kenyanthropus , and Paranthropus in the genus Australopithecus, taxonomy runs into some difficulty, as the name of species incorporates their genus. According to cladistics, groups should not be left paraphyletic, where it is kept not consisting of a common ancestor and all of its descendants. [23] [24] [25] [26] [27] [28] 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 [29] (or even Pan sapiens [30] [31] ), or to move some Australopithecus species into new genera. [7]

In 2002 and again in 2007, Cele-Conde et al. suggested that A. africanus be moved to Paranthropus. [6] On the basis of craniodental evidence, Strait and Grine (2004) suggest that A. anamensis and A. garhi should be assigned to new genera. [32] It is debated whether or not A. bahrelghazali should be considered simply a western variant of A. afarensis instead of a separate species. [33] [34]

African hominin timeline(in mya)
View references
H. sapiensH. nalediH. rhodesiensisH. ergasterAu. sedibaP. robustusP. boiseiH. rudolfensisH. habilisAu. garhiP. aethiopicusLD 350-1K. platyopsAu. bahrelghazaliAu. deyiremedaAu. africanusAu. afarensisAu. anamensisAr. ramidusAr. kadabbaAustralopithecus

Evolution

Map of the fossil sites of the early australopithecines in Africa Map of the fossil sites of the early hominids (4.4-1M BP).svg
Map of the fossil sites of the early australopithecines in Africa

A. anamensis may have descended from or was closely related to Ardipithecus ramidus . [35] A. anamensis shows some similarities to both Ar. ramidus and Sahelanthropus . [35]

Australopiths shared several traits with modern apes and humans, and were widespread throughout Eastern and Northern Africa 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. [36]

According to the Chimpanzee Genome Project, 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. [37] Sahelanthropus tchadensis , commonly called "Toumai", is about seven million years old and Orrorin tugenensis 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.[ citation needed ] One theory suggests that the human and chimpanzee lineages diverged somewhat at first, then some populations interbred around one million years after diverging. [37]

Anatomy

Reconstruction of a largely hairless male A. sediba by Adrie and Alfons Kennis at the Neanderthal Museum, Germany Australopithecus sediba (Fundort Malapa).jpg
Reconstruction of a largely hairless male A. sediba by Adrie and Alfons Kennis at the Neanderthal Museum, Germany

The brains of most species of Australopithecus were roughly 35% of the size of a modern human brain [38] with an endocranial volume average of 466 cc (28.4 cu in). [12] Although this is more than the average endocranial volume of chimpanzee brains at 360 cc (22 cu in) [12] the earliest australopiths (A. anamensis) appear to have been within the chimpanzee range, [35] whereas some later australopith specimens have a larger endocranial volume than that of some early Homo fossils. [12]

Most species of Australopithecus were diminutive and gracile, usually standing 1.2 to 1.4 m (3 ft 11 in to 4 ft 7 in) tall. It is possible that they exhibited a considerable degree of sexual dimorphism, males being larger than females. [39] 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. [39] One paper finds that A. afarensis had a level of dimorphism close to modern humans. [40]

According to A. Zihlman, Australopithecus body proportions closely resemble those of bonobos (Pan paniscus), [41] leading evolutionary biologist Jeremy Griffith to suggest that bonobos may be phenotypically similar to Australopithecus. [42] Furthermore, thermoregulatory models suggest that australopiths were fully hair covered, more like chimpanzees and bonobos, and unlike humans. [43]

Australopithecus afarensis model at the Smithsonian National Museum of Natural History. This reconstruction depicts the facultative bipedalism hypothesis, indicated by the use of the tree for stabilization. Australopithecus afarensis model reconstruction at the Smithsonian National Museum of Natural History.jpg
Australopithecus afarensis model at the Smithsonian National Museum of Natural History. This reconstruction depicts the facultative bipedalism hypothesis, indicated by the use of the tree for stabilization.

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.[ citation needed ] Earlier fossils, such as Orrorin tugenensis , 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. [44] Major changes to the pelvis and feet had already taken place before Australopithecus. [45] It was once thought that humans descended from a knuckle-walking ancestor, [46] but this is not well-supported. [47]

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. [48] The molars of Australopithecus 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. [48] However, australopiths generally evolved a larger postcanine dentition with thicker enamel. [49] Australopiths in general had thick enamel, like Homo, while other great apes have markedly thinner enamel. [48] Robust australopiths wore their molar surfaces down flat, unlike the more gracile species, who kept their crests. [48]

Diet

Paranthropus boisei IMG 2933-white.jpg
Australopithecus afarensis Cleveland Museum.jpg
The robust Paranthropus boisei (left) vs the gracile A. anamensis (right)

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 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. [50] 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). [51] 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. [48]

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. [52] In 2005, fossil animal bones with butchery marks dating to 2.6 million years old were found at the site of Gona, Ethiopia. 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. [53] 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. [54]

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. [48] 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. [55] [56] In a 1979 preliminary microwear study of Australopithecus fossil teeth, anthropologist Alan Walker theorized that robust australopiths ate predominantly fruit (frugivory). [57]

A study in 2018 found non-carious cervical lesions, caused by acid erosion, on the teeth of A. africanus , probably caused by consumption of acidic fruit. [58]

Technology

It is debated if the Australopithecus hand was anatomically capable of producing stone tools. [59] A. garhi was associated with large mammal bones bearing evidence of processing by stone tools may indicate australopithecine tool production. [60] [61] [62] [63] Stone tools dating to roughly the same time as A. garhi (about 2.6 mya) were later discovered at the nearby Gona and Ledi-Geraru sites, but the appearance of Homo at Ledi-Geraru (LD 350-1) casts doubt on australopithecine authorship. [64]

In 2010, cut marks dating to 3.4 mya on a bovid leg were found at the Dikaka site, which were at first attributed to butchery by A. afarensis, [65] but because the fossil came from a sandstone unit (and were modified by abrasive sand and gravel particles during the fossilisation process), the attribution to butchery is dubious. [66]

In 2015, the Lomekwi culture was discovered at Lake Turkana dating to 3.3 mya, possibly attributable to Kenyanthropus [67] or A. deyiremeda. [68]

Notable specimens

See also

Related Research Articles

<span class="mw-page-title-main">Homininae</span> Subfamily of mammals

Homininae, also called "African hominids" or "African apes", is a subfamily of Hominidae. It includes two tribes, with their extant as well as extinct species: 1) the tribe Hominini ―and 2) the tribe Gorillini (gorillas). Alternatively, the genus Pan is sometimes considered to belong to its own third tribe, Panini. Homininae comprises all hominids that arose after orangutans split from the line of great apes. The Homininae cladogram has three main branches, which lead to gorillas and to humans and chimpanzees. There are two living species of Panina and two living species of gorillas, but only one extant human species. Traces of extinct Homo species, including Homo floresiensis have been found with dates as recent as 40,000 years ago. Organisms in this subfamily are described as hominine or hominines.

<i>Kenyanthropus</i> Oldest-known tool-making hominin

Kenyanthropus is a genus of extinct hominin 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 old Homo rudolfensis, or K. rudolfensis. Before its naming in 2001, Australopithecus afarensis was widely regarded as the only australopithecine to exist during the Middle Pliocene, but Kenyanthropus evinces a greater diversity than once acknowledged. Kenyanthropus is most recognisable by an unusually flat face and small teeth for such an early hominin, with values on the extremes or beyond the range of variation for australopithecines in regard to these features. Multiple australopithecine species may have coexisted by foraging for different food items, which may be reason why these apes anatomically differ in features related to chewing.

<i>Orrorin</i> Postulated early hominin discovered in Kenya

Orrorin is an extinct genus of primate within Homininae from the Miocene Lukeino Formation and Pliocene Mabaget Formation, both of Kenya.

<i>Australopithecus afarensis</i> Extinct hominid from the Pliocene of East Africa

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 take place until the 1970s. From 1972 to 1977, the International Afar Research Expedition—led by anthropologists Maurice Taieb, Donald Johanson and Yves Coppens—unearthed several hundreds of hominin specimens in Hadar, Ethiopia, the most significant being the exceedingly well-preserved skeleton AL 288-1 ("Lucy") and the site AL 333. Beginning in 1974, Mary Leakey led an expedition into Laetoli, Tanzania, and notably recovered fossil trackways. In 1978, the species was first described, but this was followed by arguments for splitting the wealth of specimens into different species given the wide range of variation which had been attributed to sexual dimorphism. A. afarensis probably descended from A. anamensis and is hypothesised to have given rise to Homo, though the latter is debated.

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 lines within the family Hominidae, working from biological evidence and cultural evidence.

<span class="mw-page-title-main">Sterkfontein</span> Archaeological site in South Africa

Sterkfontein is a set of limestone caves of special interest in paleoanthropology located in Gauteng province, about 40 kilometres (25 mi) northwest of Johannesburg, South Africa in the Muldersdrift area close to the town of Krugersdorp. The archaeological sites of Swartkrans and Kromdraai are in the same area. Sterkfontein is a South African National Heritage Site and was also declared a World Heritage Site in 2000. The area in which it is situated is known as the Cradle of Humankind. The Sterkfontein Caves are also home to numerous wild African species including Belonogaster petiolata, a wasp species of which there is a large nesting presence.

<i>Australopithecus africanus</i> Extinct hominid from South Africa

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, Sterkfontein, Makapansgat, and Gladysvale. The first specimen, the Taung child, was described by anatomist Raymond Dart in 1924, and was the first early hominin found. However, its closer relations to humans than to other apes would not become widely accepted until the middle of the century because most had believed humans evolved outside of Africa. It is unclear how A. africanus relates to other hominins, being variously placed as ancestral to Homo and Paranthropus, to just Paranthropus, or to just P. robustus. The specimen "Little Foot" is the most completely preserved early hominin, with 90% of the skeleton intact, and the oldest South African australopith. However, it is controversially suggested that it and similar specimens be split off into "A. prometheus".

<i>Australopithecus anamensis</i> Extinct hominin from Pliocene east Africa

Australopithecus anamensis is a hominin species that lived approximately between 4.2 and 3.8 million years ago and is the oldest known Australopithecus species, living during the Plio-Pleistocene era.

<i>Paranthropus aethiopicus</i> Extinct species of hominin of East Africa

Paranthropus aethiopicus is an extinct species of robust australopithecine from the Late Pliocene to Early Pleistocene of East Africa about 2.7–2.3 million years ago. However, it is much debated whether or not Paranthropus is an invalid grouping and is synonymous with Australopithecus, so the species is also often classified as Australopithecus aethiopicus. Whatever the case, it is considered to have been the ancestor of the much more robust P. boisei. It is debated if P. aethiopicus should be subsumed under P. boisei, and the terms P. boisei sensu lato and P. boisei sensu stricto can be used to respectively include and exclude P. aethiopicus from P. boisei.

<i>Australopithecus garhi</i> Extinct hominid from the Afar Region of Ethiopia 2.6–2.5 million years ago

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 skeletal elements uncovered in the three years preceding. A. garhi was originally considered to have been a direct ancestor to Homo and the human line, but is now thought to have been an offshoot. Like other australopithecines, A. garhi had a brain volume of 450 cc (27 cu in); a jaw which jutted out (prognathism); relatively large molars and premolars; adaptations for both walking on two legs (bipedalism) and grasping while climbing (arboreality); and it is possible that, though unclear if, males were larger than females. One individual, presumed female based on size, may have been 140 cm tall.

<i>Paranthropus robustus</i> Extinct species of hominin of South Africa

Paranthropus robustus is a species of robust australopithecine from the Early and possibly Middle Pleistocene of the Cradle of Humankind, South Africa, about 2.27 to 0.87 million years ago. It has been identified in Kromdraai, Swartkrans, Sterkfontein, Gondolin, Cooper's, and Drimolen Caves. Discovered in 1938, it was among the first early hominins described, and became the type species for the genus Paranthropus. However, it has been argued by some that Paranthropus is an invalid grouping and synonymous with Australopithecus, so the species is also often classified as Australopithecus robustus.

<i>Paranthropus boisei</i> Extinct species of hominin of East Africa

Paranthropus boisei is a species of australopithecine from the Early Pleistocene of East Africa about 2.5 to 1.15 million years ago. The holotype specimen, OH 5, was discovered by palaeoanthropologist Mary Leakey in 1959 at Olduvai Gorge, Tanzania and described by her husband Louis a month later. It was originally placed into its own genus as "Zinjanthropus boisei", but is now relegated to Paranthropus along with other robust australopithecines. However, it is also argued that Paranthropus is an invalid grouping and synonymous with Australopithecus, so the species is also often classified as Australopithecus boisei.

<span class="mw-page-title-main">Hominini</span> Tribe of mammals

The Hominini form a taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera Homo (humans) and Pan and in standard usage excludes the genus Gorilla (gorillas).

Orthograde is a term derived from Greek ὀρθός, orthos + Latin gradi that describes a manner of walking which is upright, with the independent motion of limbs. Both New and Old World monkeys are primarily arboreal, and they have a tendency to walk with their limbs swinging in parallel to one another. This differs from the manner of walking demonstrated by the apes.

<span class="mw-page-title-main">Australopithecine</span> Extinct subtribe of the Hominini tribe, and members of the human clade

The australopithecines, formally Australopithecina or Hominina, are generally any species in the related genera of Australopithecus and Paranthropus. It may also include members of Kenyanthropus, Ardipithecus, and Praeanthropus. The term comes from a former classification as members of a distinct subfamily, the Australopithecinae. They are now classified within the Australopithecina subtribe of the Hominini tribe. All these related species are now sometimes collectively termed australopithecines, australopiths or homininians. They are the extinct, close relatives of modern humans and, together with the extant genus Homo, comprise the human clade. Members of the human clade, i.e. the Hominini after the split from the chimpanzees, are now called Hominina.

Australopithecus bahrelghazali is an extinct species of australopithecine discovered in 1995 at Koro Toro, Bahr el Gazel, Chad, existing around 3.5 million years ago in the Pliocene. It is the first and only australopithecine known from Central Africa, and demonstrates that this group was widely distributed across Africa as opposed to being restricted to East and southern Africa as previously thought. The validity of A. bahrelghazali has not been widely accepted, in favour of classifying the specimens as A. afarensis, a better known Pliocene australopithecine from East Africa, because of the anatomical similarity and the fact that A. bahrelghazali is known only from 3 partial jawbones and an isolated premolar. The specimens inhabited a lakeside grassland environment with sparse tree cover, possibly similar to the modern Okavango Delta, and similarly predominantly ate C4 savanna foods—such as grasses, sedges, storage organs, or rhizomes—and to a lesser degree also C3 forest foods—such as fruits, flowers, pods, or insects. However, the teeth seem ill-equipped to process C4 plants, so its true diet is unclear.

<span class="mw-page-title-main">Middle Awash</span> UNESCO World Heritage Site in Ethiopia

The Middle Awash is a paleoanthropological research area in the northwest corner of Gabi Rasu in the Afar Region along the Awash River in Ethiopia's Afar Depression. It is a unique natural laboratory for the study of human origins and evolution and a number of fossils of the earliest hominins, particularly of the Australopithecines, as well as some of the oldest known Olduwan stone artifacts, have been found at the site—all of late Miocene, the Pliocene, and the very early Pleistocene times, that is, about 5.6 million years ago (mya) to 2.5 mya. It is broadly thought that the divergence of the lines of the earliest humans (hominins) and of chimpanzees (hominids) was completed near the beginning of that time range, or sometime between seven and five mya. However, the larger community of scientists provide several estimates for periods of divergence that imply a greater range for this event, see CHLCA: human-chimpanzee split.

<span class="mw-page-title-main">Postcanine megadontia</span> Relative enlargement of pre-molars and molars compared with other teeth.

Post-canine megadontia is a relative enlargement of the molars and premolars compared to the size of the incisors and canines. This phenomenon is seen in some early hominid ancestors such as Paranthropus aethiopicus.

<i>Australopithecus sediba</i> Two-million-year-old hominin from the Cradle of Humankind

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 paratype MH2. They date to about 1.98 million years ago in the Early Pleistocene, and coexisted with Paranthropus robustus and Homo ergaster / Homo erectus. Malapa is interpreted as having been a natural death trap, the base of a long vertical shaft which creatures could accidentally fall into. A. sediba was initially described as being a potential human ancestor, and perhaps the progenitor of Homo, but this is contested and it could also represent a late-surviving population or sister species of A. africanus which had earlier inhabited the area.

Australopithecus deyiremeda is an extinct species of australopithecine from Woranso–Mille, Afar Region, Ethiopia, about 3.5 to 3.3 million years ago during the Pliocene. Because it is known only from three partial jawbones, it is unclear if these specimens indeed represent a unique species or belong to the much better-known A. afarensis. A. deyiremeda is distinguished by its forward-facing cheek bones and small cheek teeth compared to those of other early hominins. It is unclear if a partial foot specimen exhibiting a dextrous big toe can be assigned to A. deyiremeda. A. deyiremeda lived in a mosaic environment featuring both open grasslands and lake- or riverside forests, and anthropologist Fred Spoor suggests it may have been involved in the Kenyan Lomekwi stone-tool industry typically assigned to Kenyanthropus. A. deyiremeda coexisted with A. afarensis, and they may have exhibited niche partitioning to avoid competing with each other for the same resources, such as by relying on different fallback foods during leaner times.

References

  1. ↑ Jones, Daniel (2003) [1917], Peter Roach; James Hartmann; Jane Setter (eds.), English Pronouncing Dictionary, Cambridge: Cambridge University Press, ISBN   978-3-12-539683-8
  2. ↑ "Glossary. American Museum of Natural History". Archived from the original on 20 November 2021.
  3. ↑ Wood & Richmond 2000.
  4. ↑ Briggs & Crowther 2008, p. 124.
  5. ↑ Wood 2010.
  6. 1 2 3 Haile-Selassie, Y (27 October 2010). "Phylogeny of early Australopithecus: new fossil evidence from the Woranso-Mille (central Afar, Ethiopia)". Philosophical Transactions of the Royal Society B: Biological Sciences. 365 (1556): 3323–3331. doi:10.1098/rstb.2010.0064. PMC   2981958 . PMID   20855306.
  7. 1 2 Hawks, John (2017-03-20). "The plot to kill Homo habilis". Medium. Retrieved 2019-03-24.
  8. ↑ Asfaw, B; White, T; Lovejoy, O; Latimer, B; Simpson, S; Suwa, G (1999). "Australopithecus garhi: a new species of early hominid from Ethiopia". Science . 284 (5414): 629–35. Bibcode:1999Sci...284..629A. doi:10.1126/science.284.5414.629. PMID   10213683.
  9. ↑ "Exploring the fossil record: Australopithecus africanus". Bradshaw Foundation . Retrieved 2019-11-11.
  10. ↑ Berger, L. R.; de Ruiter, D. J.; Churchill, S. E.; Schmid, P.; Carlson, K. J.; Dirks, P. H. G. M.; Kibii, J. M. (2010). "Australopithecus sediba: a new species of Homo-like australopith from South Africa". Science . 328 (5975): 195–204. Bibcode:2010Sci...328..195B. CiteSeerX   10.1.1.729.7802 . doi:10.1126/science.1184944. PMID   20378811. S2CID   14209370.
  11. ↑ 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. ISBN   0-500-28531-4
  12. 1 2 3 4 Kimbel, W.H.; Villmoare, B. (5 July 2016). "From Australopithecus to Homo: the transition that wasn't". Philosophical Transactions of the Royal Society of London B: Biological Sciences. 371 (1698): 20150248. doi:10.1098/rstb.2015.0248. PMC   4920303 . PMID   27298460.
  13. ↑ Reardon, Sara (2012-05-03). "The humanity switch: How one gene made us brainier". New Scientist. Retrieved 2020-03-06.
  14. ↑ Sporny, Michael; Guez-Haddad, Julia; Kreusch, Annett; Shakartzi, Sivan; Neznansky, Avi; Cross, Alice; Isupov, Michail N.; Qualmann, Britta; Kessels, Michael M.; Opatowsky, Yarden (June 2017). "Structural History of Human SRGAP2 Proteins". Molecular Biology and Evolution. 34 (6): 1463–1478. doi:10.1093/molbev/msx094. ISSN   0737-4038. PMC   5435084 . PMID   28333212.
  15. ↑ Tocheri, Matthew W.; Orr, Caley M.; Jocofsky, Marc C.; Marzke, Mary W. (April 2008). "The evolutionary history of the hominin hand since the last common ancestor of Pan and Homo". Journal of Anatomy . 212 (4): 544–562. doi:10.1111/j.1469-7580.2008.00865.x. PMC   2409097 . PMID   18380869.
  16. 1 2 3 Lewin, Roger (1999). "The Australopithecines". Human Evolution: An Illustrated Introduction. Blackwell Science. pp. 112–113. ISBN   0632043091.
  17. 1 2 Schwartz, Jeffrey H.; Tattersall, Ian (2015). "Defining the genus Homo". Science . 349 (931): 931–932. Bibcode:2015Sci...349..931S. doi:10.1126/science.aac6182. PMID   26315422. S2CID   206639783.
  18. ↑ Bruxelles L., Clarke R. J., Maire R., Ortega R., et Stratford D. – 2014. – Stratigraphic analysis of the Sterkfontein StW 573 Australopithecus skeleton and implications for its age. Journal of Human Evolution,
  19. ↑ "New stratigraphic research makes Little Foot the oldest complete Australopithecus".
  20. ↑ Celia W. Dugger; John Noble Wilford (April 8, 2010). "New Hominid Species Discovered in South Africa". The New York Times.
  21. ↑ Cela-Conde, C. J.; Ayala, F. J. (2003). "Genera of the human lineage". Proceedings of the National Academy of Sciences. 100 (13): 7684–7689. Bibcode:2003PNAS..100.7684C. doi: 10.1073/pnas.0832372100 . PMC   164648 . PMID   12794185.
  22. ↑ Tattersall, I. (2017). "Species, genera, and phylogenetic structure in the human fossil record: a modest proposal". Evolutionary Anthropology: Issues, News, and Reviews. 26 (3): 116–118. doi:10.1002/evan.21523. PMID   28627785. S2CID   43487900. Forms such as Ardipithecus, Sahelanthropus, and Orrorin have also been admitted to the pantheon, though this has clearly been facilitated by their great age. And in a nod to history, the venerable genus Paranthropus has been grandfathered in for use by those who think it useful. But except for the widely dismissed revival of Praeanthropus, there has been little real rethinking of the hugely minimalist hominid taxonomy, generic as well as specific, that Mayr foisted on us all those years ago...
  23. ↑ Kimbel, William H. (2015), "The Species and Diversity of Australopiths", in Henke, Winfried; Tattersall, Ian (eds.), Handbook of Paleoanthropology, Springer Berlin Heidelberg, pp. 2071–2105, doi:10.1007/978-3-642-39979-4_50, ISBN   9783642399787
  24. ↑ Fleagle, John G. (2013-03-08). Primate Adaptation and Evolution. Academic Press. p. 364. ISBN   9780123786333.
  25. ↑ Schwarz, J.H. (2004). "Barking up the wrong ape--australopiths and the quest for chimpanzee characters in hominid fossils". Collegium Antropologicum. 28 Suppl 2: 87–101. PMID   15571084. S2CID   12944654.
  26. ↑ Cartmill, Matt (2018). "A sort of revolution: Systematics and physical anthropology in the 20th century". American Journal of Physical Anthropology . 165 (4): 677–687. doi: 10.1002/ajpa.23321 . hdl:2144/29233. PMID   29574829.
  27. ↑ Villmoare, Brian (2018-01-30). "Early Homo and the role of the genus in paleoanthropology". American Journal of Physical Anthropology . 165: 72–89. doi: 10.1002/ajpa.23387 . ISSN   0002-9483. PMID   29380889.
  28. ↑ "2 @BULLET Enhanced cognitive capacity as a contingent fact of hominid phylogeny". ResearchGate. Retrieved 2019-01-12.
  29. ↑ Flegr, Jaroslav (2013-11-27). "Why Drosophila is not Drosophila any more, why it will be worse and what can be done about it?". Zootaxa . 3741 (2): 295–300. doi:10.11646/zootaxa.3741.2.8. ISSN   1175-5334. PMID   25112991.
  30. ↑ Pietrzak-Franger, Monika; Schaff, Barbara; Voigts, Eckart (2014-02-28). Reflecting on Darwin. Ashgate Publishing, Ltd. p. 118. ISBN   9781472414090.
  31. ↑ Gribbin, John (2009-08-27). Science: A History: A History. Penguin Books Limited. ISBN   9780141042220.
  32. ↑ Strait, David S.; Grine, Frederick E. (December 2004). "Inferring hominoid and early hominid phylogeny using craniodental characters: the role of fossil taxa". Journal of Human Evolution . 47 (6): 399–452. doi:10.1016/j.jhevol.2004.08.008. PMID   15566946.
  33. ↑ Ward, Carol V.; Hammind, Ashley S. (2016). "Australopithecus and Kin". Nature Education Knowledge. 7 (3): 1. Retrieved 2019-11-13.
  34. ↑ White, Tim D. (2002). "Chapter 24 Earliest Hominids". In Hartwig, Walter Carl (ed.). The Primate Fossil Record (Cambridge Studies in Biological and Evolutionary Anthropology). Cambridge University Press. ISBN   0-521-66315-6.
  35. 1 2 3 Haile-Selassie, Yohannes; Melillo, Stephanie M.; Vazzana, Antonino; Benazzi, Stefano; Ryan, Timothy M. (2019). "A 3.8-million-year-old hominin cranium from Woranso-Mille, Ethiopia". Nature . 573 (7773): 214–219. Bibcode:2019Natur.573..214H. doi:10.1038/s41586-019-1513-8. hdl: 11585/697577 . PMID   31462770. S2CID   201656331.
  36. ↑ David A. Raichlen; Adam D. Gordon; William E. H. Harcourt-Smith; Adam D. Foster; Wm. Randall Haas Jr (2010). Rosenberg, Karen (ed.). "Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics". PLOS ONE . 5 (3): e9769. Bibcode:2010PLoSO...5.9769R. doi: 10.1371/journal.pone.0009769 . PMC   2842428 . PMID   20339543.
  37. 1 2 Bower, Bruce (May 20, 2006). "Hybrid-Driven Evolution: Genomes show complexity of human-chimp split". Science News . 169 (20): 308–309. doi:10.2307/4019102. JSTOR   4019102.
  38. ↑ "Australopithecus afarensis". The Smithsonian Institution's Human Origins Program. 2010-01-25. Retrieved 2020-01-09.
  39. 1 2 Beck, Roger B.; Linda Black; Larry S. Krieger; Phillip C. Naylor; Dahia Ibo Shabaka (1999). World History: Patterns of Interaction . McDougal Littell. ISBN   978-0-395-87274-1.
  40. ↑ Reno, Philip L., Richard S. Meindl, Melanie A. McCollum, and C. Owen Lovejoy. 2003."Sexual Dimorphism in Australopithecus Afarensis Was Similar to That of Modern Humans." Proceedings of the National Academy of Sciences 100 (16): 9404–9. https://doi.org/10.1073/pnas.1133180100.
  41. ↑ Zihlman AL, Cronin JE, Cramer DL, Sarich VM (1978). "Pygmy chimpanzee as a possible prototype for the common ancestor of humans, chimpanzees and gorillas". Nature . 275 (5682): 744–6. Bibcode:1978Natur.275..744Z. doi:10.1038/275744a0. PMID   703839. S2CID   4252525.
  42. ↑ Griffith, Jeremy (2013). Freedom Book 1. Vol. Part 8:4G. WTM Publishing & Communications. ISBN   978-1-74129-011-0 . Retrieved 28 March 2013.
  43. ↑ David-Barrett, T.; Dunbar, R.I.M. (2016). "Bipedality and Hair-loss Revisited: The Impact of Altitude and Activity Scheduling". Journal of Human Evolution . 94: 72–82. doi:10.1016/j.jhevol.2016.02.006. PMC   4874949 . PMID   27178459.
  44. ↑ Thorpe, SK; Holder, RL; Crompton, RH. (2007). "Origin of human bipedalism as an adaptation for locomotion on flexible branches". Science . 316 (5829): 1328–31. Bibcode:2007Sci...316.1328T. doi:10.1126/science.1140799. PMID   17540902. S2CID   85992565.
  45. ↑ Lovejoy, C. O. (1988). "Evolution of Human walking". Scientific American . 259 (5): 82–89. Bibcode:1988SciAm.259e.118L. doi:10.1038/scientificamerican1188-118. PMID   3212438.
  46. ↑ Richmond, BG; Begun, DR; Strait, DS (2001). "Origin of human bipedalism: The knuckle-walking hypothesis revisited". American Journal of Physical Anthropology . Suppl 33: 70–105. doi: 10.1002/ajpa.10019 . PMID   11786992.
  47. ↑ Kivell, TL; Schmitt, D. (Aug 2009). "Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor". Proceedings of the National Academy of Sciences of the United States of America . 106 (34): 14241–6. Bibcode:2009PNAS..10614241K. doi: 10.1073/pnas.0901280106 . PMC   2732797 . PMID   19667206.
  48. 1 2 3 4 5 6 Kay, R.F., 1985, 'DENTAL EVIDENCE FOR THE DIET OF AUSTRALOPITHECUS', Annual Review of Anthropology , 14, pp. 315-341.
  49. ↑ McHenry, H. M. (2009). "Human Evolution". In Michael Ruse; Joseph Travis (eds.). Evolution: The First Four Billion Years. Cambridge, Massachusetts: The Belknap Press of Harvard University Press. pp.  261–265. ISBN   978-0-674-03175-3.
  50. ↑ Grine FE (1986). "Dental evidence for dietary differences in Australopithecus and Paranthropus – a quantitative-analysis of permanent molar microwear". Journal of Human Evolution . 15 (8): 783–822. doi:10.1016/S0047-2484(86)80010-0.
  51. ↑ Martínez, L.; Estebaranz-Sánchez, F.; Galbany, J.; Pérez-Pérez, A. (2016). "Testing Dietary Hypotheses of East African Hominines Using Buccal Dental Microwear Data". PLOS ONE . 11 (11): 1–25. Bibcode:2016PLoSO..1165447M. doi: 10.1371/journal.pone.0165447 . PMC   5112956 . PMID   27851745.
  52. ↑ Billings, Tom. "Comparative Anatomy and Physiology Brought Up to Date--continued, Part 3B)". Archived from the original on 15 December 2006. Retrieved 2007-01-06.
  53. ↑ Nature. "Evidence for Meat-Eating by Early Humans".
  54. ↑ Nature (2010). "Butchering dinner 3.4 million years ago". Nature . doi:10.1038/news.2010.399.
  55. ↑ Ungar, P. S.; Grine, F. E.; Teaford, M. F. (2008). "Dental Microwear and Diet of the Plio-Pleistocene Hominin Paranthropus boisei". PLOS ONE. 3 (4): e2044. Bibcode:2008PLoSO...3.2044U. doi: 10.1371/journal.pone.0002044 . PMC   2315797 . PMID   18446200.
  56. ↑ Scott RS, Ungar PS, Bergstrom TS, Brown CA, Grine FE, Teaford MF, Walker A (2005). "Dental microwear texture analysis shows within-species diet variability in fossil hominins" (PDF). Nature . 436 (7051): 693–695. Bibcode:2005Natur.436..693S. doi:10.1038/nature03822. PMID   16079844. S2CID   4431062.
  57. ↑ Rensberger, Boyce (1979-05-15). "Teeth Show Fruit Was The Staple". The New York Times . Retrieved 11 August 2021.
  58. ↑ Towle, Ian; Irish, Joel D.; Elliott, Marina; De Groote, Isabelle (2018-09-01). "Root grooves on two adjacent anterior teeth of Australopithecus africanus" (PDF). International Journal of Paleopathology. 22: 163–167. doi:10.1016/j.ijpp.2018.02.004. ISSN   1879-9817. PMID   30126662. S2CID   52056962.
  59. ↑ Domalain, Mathieu; Bertin, Anne; Daver, Guillaume (2017-08-01). "Was Australopithecus afarensis able to make the Lomekwian stone tools? Towards a realistic biomechanical simulation of hand force capability in fossil hominins and new insights on the role of the fifth digit". Comptes Rendus Palevol. Hominin biomechanics, virtual anatomy and inner structural morphology: From head to toe. A tribute to Laurent Puymerail. 16 (5): 572–584. Bibcode:2017CRPal..16..572D. doi: 10.1016/j.crpv.2016.09.003 . ISSN   1631-0683.
  60. ↑ Semaw, S.; Renne, P.; Harris, J. W. K. (1997). "2.5-million-year-old stone tools from Gona, Ethiopia". Nature. 385 (6614): 333–336. Bibcode:1997Natur.385..333S. doi:10.1038/385333a0. PMID   9002516. S2CID   4331652.
  61. ↑ Semaw, S.; Rogers, M. J.; Quade, J.; et al. (2003). "2.6-Million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia". Journal of Human Evolution. 45 (2): 169–177. doi:10.1016/s0047-2484(03)00093-9. PMID   14529651.
  62. ↑ Asfaw, Berhane; White, Tim; Lovejoy, Owen; Latimer, Bruce; Simpson, Scott; Suwa, Gen (23 April 1999). "Australopithecus garhi: A New Species of Early Hominid from Ethiopia". Science . 284 (5414): 629–635. Bibcode:1999Sci...284..629A. doi:10.1126/science.284.5414.629. PMID   10213683.
  63. ↑ de Heinzelin, Jean; Clark, J. Desmond; White, Tim; Hart, William; Renne, Paul; WoldeGabriel, Giday; Beyene, Yonas; Vrba, Elisabeth (23 April 1999). "Environment and Behavior of 2.5-Million-Year-Old Bouri Hominids". Science . 284 (5414): 625–629. Bibcode:1999Sci...284..625D. doi:10.1126/science.284.5414.625. PMID   10213682.
  64. ↑ Braun, D. R.; Aldeias, V.; Archer, W.; et al. (2019). "Earliest known Oldowan artifacts at >2.58 Ma from Ledi-Geraru, Ethiopia, highlight early technological diversity". Proceedings of the National Academy of Sciences . 116 (24): 11, 712–11, 717. Bibcode:2019PNAS..11611712B. doi: 10.1073/pnas.1820177116 . PMC   6575601 . PMID   31160451.
  65. ↑ McPherron, S. P.; Alemseged, Z.; Marean, C. W.; et al. (2010). "Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia". Nature. 466 (7308): 857–860. Bibcode:2010Natur.466..857M. doi:10.1038/nature09248. PMID   20703305. S2CID   4356816.
  66. ↑ Domínguez-Rodrigo, M.; Pickering, T. R.; Bunn, H. T. (2010). "Configurational approach to identifying the earliest hominin butchers". Proceedings of the National Academy of Sciences. 107 (49): 20929–20934. Bibcode:2010PNAS..10720929D. doi: 10.1073/pnas.1013711107 . PMC   3000273 . PMID   21078985.
  67. ↑ Harmand, S.; Lewis, J. E.; Feibel, C. S.; et al. (2015). "3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya". Nature. 521 (7552): 310–315. Bibcode:2015Natur.521..310H. doi:10.1038/nature14464. PMID   25993961. S2CID   1207285.
  68. ↑ Spoor, Fred (2015). "Palaeoanthropology: The middle Pliocene gets crowded". Nature. 521 (7553): 432–433. Bibcode:2015Natur.521..432S. doi: 10.1038/521432a . ISSN   0028-0836. PMID   26017440. S2CID   4472489.

Sources

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.