Ardipithecus kadabba

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Ardipithecus kadabba
Temporal range: Messinian, 5.77–5.54  Ma
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Ardipithecus kadabba fossils.jpg
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Hominidae
Subfamily: Homininae
Tribe: Hominini
Genus: Ardipithecus
Species:
A. kadabba
Binomial name
Ardipithecus kadabba

Ardipithecus kadabba is the scientific classification given to fossil remains "known only from teeth and bits and pieces of skeletal bones", [1] originally estimated to be 5.8 to 5.2 million years old, and later revised to 5.77 to 5.54 million years old. [2] According to the first description, these fossils are close to the common ancestor of chimps and humans. Their development lines are estimated to have parted 6.55.5 million years ago. It has been described as a "probable chronospecies" (i.e. ancestor) of A. ramidus . Although originally considered a subspecies of A. ramidus, in 2004 anthropologists Yohannes Haile-Selassie, Gen Suwa, and Tim D. White published an article elevating A. kadabba to species level on the basis of newly discovered teeth from Ethiopia. These teeth show "primitive morphology and wear pattern" which demonstrate that A. kadabba is a distinct species from A. ramidus.

Contents

The specific name comes from the Afar word for "basal family ancestor". [3]

Taxonomy

Fossil remains were first described in 2001 by Ethiopian paleoanthropologist Yohannes Haile-Selassie based on bones collected from five localities in the Middle Awash, Ethiopia. Haile-Selassie initially classified them as Ardipithecus ramidus kadabba, with kadabba deriving from the Afar language meaning "basal family ancestor". [4] In 2004, he, along with Japanese paleoanthropologist Gen Suwa and American paleoanthropologist Tim D. White, elevated it to species level as A. kadabba based on apparently primitive features compared to A. ramidus. [5] A. kadabba is considered to have been the direct ancestor of A. ramidus, making Ardipithecus a chronospecies. [6]

Along with elevating it to species level, they suggested that Ardipithecus, Sahelanthropus , and Orrorin could potentially belong to the same genus. [5] In 2008, American paleoanthropologists Bernard Wood and Nicholas Lonerga said that the larger ape-like canines of A. kadabba cast doubt on its assignment to the human line, [7] but the position of Ardipithecus near humans has been reaffirmed by the discoverers and colleagues. They see a lineage of apes whose teeth continually reduce in size: A. kadabbaA. ramidus Australopithecus anamensis Au africanus , though they are unsure if Ardipithecus were the ancestors to these Australopithecus species, or were only closely related. [8]

Evolutionary tree according to a 2019 study: [9]

Hominini

Chimpanzee

Sahelanthropus

Ardipithecus

A. anamensis

A. afarensis

Paranthropus

P. aethiopicus

P. boisei

P. robustus

A. africanus

A. garhi

H. floresiensis

A. sediba

H. habilis

Other Homo

Description

A. kadabba is known from nineteen specimens which reveal elements of the teeth, jaw, feet, and hands and arms. The holotype specimen, ALA-VP-2/10, is a right lower jaw fragment with a third molar, discovered in December 1997, and five associated left lower jaw teeth or root fragments collected in 1999.

This correction of the initial allocation of the fossil record was based on the argument that Ardipithecus kadabba had more "primitive" features than other Ardipithecus fossils. Ardipithecus kadabba thus also has a greater similarity with the genera Sahelanthropus and Orrorin . These statements were based on additional bone finds that came to light in November 2002 and were dated at 5.8 to 5.6 million years.

At the same time, it was emphasized that evidence could be found of a reduced "honing" complex, traces on the teeth that arise when the canines rub against each other when biting, constantly sharpening their peaks, which has been found in all older finds. The loss of this feature in the successor species of Ardipithecus ramidus has been used for the allocation of discoveries in that line of development of great apes that led to the australopithecines and the genus Homo.

Paleoecology

The first description suggested that Ardipithecus kadabba lived in a habitat that consisted of forests, wooded savannas, and open water areas, as had been described for Sahelanthropus . [10]

Related Research Articles

<i>Ardipithecus</i> Extinct genus of hominins

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 chimpanzees, the relation of this genus to human ancestors and whether it is a hominin is now a matter of debate. Two fossil 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. Initial behavioral analysis indicated that Ardipithecus could be very similar to chimpanzees, however more recent analysis based on canine size and lack of canine sexual dimorphism indicates that Ardipithecus was characterised by reduced aggression, and that they more closely resemble bonobos.

<i>Australopithecus</i> Genus of hominin ancestral to modern humans

Australopithecus is a genus of early hominins that existed in Africa during the Late Pliocene and Early Pleistocene. The genus Homo emerged within Australopithecus, as sister to e.g. Australopithecus sediba. Also the genera Paranthropus and Kenyanthropus emerged within Australopithecus. Australopithecus is a member of the subtribe Australopithecina, which sometimes also includes Ardipithecus, 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.

<i>Sahelanthropus</i> Extinct hominid from Miocene Africa

Sahelanthropus tchadensis is an extinct species of the Homininae dated to about 7 million years ago, during the Miocene epoch. The species, and its genus Sahelanthropus, was announced in 2002, based mainly on a partial cranium, nicknamed Toumaï, discovered in northern Chad.

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.

<i>Mellivora</i> Genus of mammals

Mellivora is a genus of mustelids that contains the honey badger or ratel (Mellivora capensis). It is also the sole living representative of the subfamily Mellivorinae. Additionally, two extinct species are known. The honey badger is native to much of Africa and South Asia, while fossil relatives occurred in those areas and Southern Europe.

<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.

<span class="mw-page-title-main">Afar Triangle</span> Geological depression caused by the Afar Triple Junction

The Afar Triangle is a geological depression caused by the Afar Triple Junction, which is part of the Great Rift Valley in East Africa. The region has disclosed fossil specimens of the very earliest hominins; that is, the earliest of the human clade, and it is thought by some paleontologists to be the cradle of the evolution of humans. The Depression overlaps the borders of Eritrea, Djibouti and the entire Afar Region of Ethiopia; and it contains the lowest point in Africa, Lake Assal, Djibouti, at 155 m (509 ft) below sea level.

<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.

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

Australopithecina or Hominina is a subtribe in the tribe Hominini. The members of the subtribe are generally Australopithecus, and it typically includes the earlier Ardipithecus, Orrorin, Sahelanthropus, and Graecopithecus. All these closely related species are now sometimes collectively termed australopiths or homininians. They are the extinct, close relatives of humans and, 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.

<span class="mw-page-title-main">Tim D. White</span> American paleoanthropologist

Tim D. White is an American paleoanthropologist and Professor of Integrative Biology at the University of California, Berkeley. He is best known for leading the team which discovered Ardi, the type specimen of Ardipithecus ramidus, a 4.4 million-year-old likely human ancestor. Prior to that discovery, his early career was notable for his work on Lucy as Australopithecus afarensis with discoverer Donald Johanson.

<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 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.

Aramis is a village and archaeological site in north-eastern Ethiopia, where remains of Australopithecus and Ardipithecus have been found. The village is located in Administrative Zone 5 of the Afar Region, which is part of the Afar Sultanate of Dawe, with a latitude and longitude of 10°30′N40°30′E, and is part of the, Carri Rasuk, Xaale Faagê Daqaara.

<span class="mw-page-title-main">Yohannes Haile-Selassie</span> Ethiopian paleoanthropologist

Yohannes Haile-SelassieAmbaye is an Ethiopian paleoanthropologist. An authority on pre-Homo sapiens hominids, he particularly focuses his attention on the East African Rift and Middle Awash valleys. He was curator of Physical Anthropology at the Cleveland Museum of Natural History from 2002 until 2021, and now is serving as the director of the Arizona State University Institute of Human Origins. Since founding the institute in 1981, he has been the third director after Donald Johanson and William Kimbel.

<i>Ardipithecus ramidus</i> Extinct hominin from Early Pliocene Ethiopia

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 in the trees (arboreality). However, it would not have been as efficient at bipedality as humans, nor at arboreality as non-human great apes. Its discovery, along with Miocene apes, has reworked academic understanding of the chimpanzee-human last common ancestor from appearing much like modern day chimpanzees, orangutans and gorillas to being a creature without a modern anatomical cognate.

Ardi (ARA-VP-6/500) is the designation of the fossilized skeletal remains of an Ardipithecus ramidus, thought to be an early human-like female anthropoid 4.4 million years old. It is the most complete early hominid specimen, with most of the skull, teeth, pelvis, hands and feet, more complete than the previously known Australopithecus afarensis specimen called "Lucy." In all, 125 different pieces of fossilized bone were found.

<i>Ugandax</i> Extinct genus of mammals

Ugandax is an extinct genus of bovines in the subtribe Bubalina that lived from the Miocene to the Pleistocene of Africa. Cladistic analyses suggest Ugandax represents an ancestral form of the African buffalo, Syncerus, and teeth assigned to Ugandax represent the earliest appearance of bovines in Africa.

The savannah hypothesis is a hypothesis that human bipedalism evolved as a direct result of human ancestors' transition from an arboreal lifestyle to one on the savannas. According to the hypothesis, millions of years ago hominins left the woodlands that had previously been their natural habitat, and adapted to their new habitat by walking upright.

The Middle Awash Project is an international research expedition conducted in the Afar region of Ethiopia with the goal of determining the origins of humanity. The project has the approval of the Ethiopian Culture Ministry and a strong commitment to developing Ethiopian archaeology, paleontology and geology research infrastructure. This project has discovered over 260 fossil specimens and over 17,000 vertebrate fossil specimens to date ranging from 200,000 to 6,000,000 years in age. Researchers have discovered the remains of four hominin species, the earliest subspecies of homo sapiens as well as stone tools. All specimens are permanently held at the National Museum of Ethiopia, where the project’s laboratory work is conducted year round.

Pliopapio is an extinct genus of Old World monkey known from the latest part of the Miocene to the early Pliocene Epochs from the Afar Region of Ethiopia. It was first described based on a very large series of fossils from the site of Aramis in the Middle Awash, which has been dated by 40Ar/39Ar to 4.4 million years old. It has since been found from similarly aged sediments at Gona, approximately 75 km to the North. Additional fossils from the Middle Awash extend its known time range back to at least 5.3 million years ago. There is only one known species, Pliopapio alemui.

<span class="mw-page-title-main">Prehistoric Ethiopia</span> Occurrence and people throughout Ethiopian prehistory

Ethiopia is considered the site of anatomically modern humans emergence. Archeological discoveries in the country's sites garnered specific earliest fossils succession including the female hominin Australopithecus afarensis lived 3.2 million years ago, and Ardipithecus ramidus. Human settlements in present-day Ethiopia began at least in Late Stone Age and agricultural revolution took place in the third millennium BC. Formulation of ethnolinguistic groups of Afroasiatic speakers and Nilo-Saharan people shaped with new ethnic cultural and linguistic entity by the first millennium BC.

References

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  2. Webseite von Yohannes Haile-Selassie Archived 2015-09-20 at the Wayback Machine
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