Selam (Australopithecus)

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Selam
SelamAustralopithecus.jpg
Catalog no.DIK-1/1
Common nameSelam
Species Australopithecus afarensis
Agec. 3.3 million years
Place discovered Dikika, Afar Depression, Ethiopia
Date discovered2000
Discovered by Zeresenay Alemseged

Selam (DIK-1/1) is the fossilized skull and other skeletal remains of a three-year-old Australopithecus afarensis female hominin, whose bones were first found in Dikika, Ethiopia in 2000 and recovered over the following years. [1] Although she has often been nicknamed Lucy's baby, the specimen has been dated at 3.3 million years ago, approximately 100,000 years older than "Lucy" (dated to about 3.2 mya).

Contents

Discovery

The fossils were discovered by Zeresenay Alemseged, and are remarkable for their age and condition. On 20 September 2006, the journal Nature presented the findings of a dig in Dikika, Ethiopia, a few miles south of Hadar, the well-known site where the fossil hominin known as Lucy was found. The recovered skeleton comprises almost the entire skull and torso and many parts of the limbs. The features of the skeleton suggest adaptation to walking upright (bipedalism) as well as tree-climbing, features that correspond well with the skeletal features of Lucy and other specimens of Australopithecus afarensis from Ethiopia and Tanzania. CT-scans of the skull show small canine teeth forming, indicating the specimen is female.

"Lucy's Baby" has officially been named "Selam" (ሰላም, meaning "peace"). The name was published at the announcement of the discovery at the National Museum in Addis Ababa. As part of Ethiopia's Millennium celebration a commemorative gold coin was minted and given to visiting government officials during the celebration year.

Following is an abstract of the original article describing the baby "Selam", which was authored by Zeresenay Alemseged, Fred Spoor, William H. Kimbel, René Bobe, Denis Geraads, Denné Reed and Jonathan G. Wynn. [2]

Understanding changes in ontogenetic development is central to the study of human evolution. With the exception of Neanderthals, the growth patterns of fossil hominins have not been studied comprehensively because the fossil record currently lacks specimens that document both cranial and postcranial development at young ontogenetic stages. Here we describe a well-preserved 3.3-million-year-old juvenile partial skeleton of Australopithecus afarensis discovered in the Dikika research area of Ethiopia. The skull of the approximately three-year-old presumed female shows that most features diagnostic of the species are evident even at this early stage of development. The find includes many previously unknown skeletal elements from the Pliocene hominin record, including a hyoid bone that has a typical African ape [hominid] morphology. The foot and other evidence from the lower limb provide clear evidence for bipedal locomotion, but the gorilla-like scapula and long and curved manual phalanges raise new questions about the importance of arboreal behaviour in the A. afarensis

DIK-1-1 skeleton; notice the diverging left big toe bone Resti di australopithecus afarensis detto selam, di tre anni circa, da dikika (afar), 3,3 milioni di anni fa.jpg
DIK-1-1 skeleton; notice the diverging left big toe bone

A lifelike image of Selam was published on the cover of the November 2006 issue of National Geographic .

A 2018 examination by DeSilva et al. in Science Advances concluded the hallux of the foot was evidence of hallucal grasping and tree climbing, with an ape-like low and perhaps flat arch of the foot. [3]

Selam (Australopithecus afarensis) model at California Academy of Sciences Selam (Australopithecus afarensis) model at California Academy of Sciences.jpg
Selam (Australopithecus afarensis) model at California Academy of Sciences


Evolution

Many paleoanthropologists propose that the Homo line derives from A. africanus ; in this view it might be better to place Selam in the A. africanus line, since it has more human traits than most A. afarensis (see Homininae). [ citation needed ]

Implications

Examination of the shoulder blade [4] and arms [5] of this specimen has lent support to the idea that Australopithecus afarensis climbed extensively.

See also

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>Homo habilis</i> Archaic human species from 2.8 to 1.65 mya

Homo habilis is an extinct species of archaic human from the Early Pleistocene of East and South Africa about 2.3 million years ago to 1.65 million years ago (mya). Upon species description in 1964, H. habilis was highly contested, with many researchers recommending it be synonymised with Australopithecus africanus, the only other early hominin known at the time, but H. habilis received more recognition as time went on and more relevant discoveries were made. By the 1980s, H. habilis was proposed to have been a human ancestor, directly evolving into Homo erectus, which directly led to modern humans. This viewpoint is now debated. Several specimens with insecure species identification were assigned to H. habilis, leading to arguments for splitting, namely into "H. rudolfensis" and "H. gautengensis" of which only the former has received wide support.

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

Australopithecus is a genus of early hominins that existed in Africa during the Pliocene and Early Pleistocene. The genera Homo, Paranthropus, and Kenyanthropus evolved from some Australopithecus species. 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>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 Gauteng, South Africa

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Hadar or Hadar Formation is a paleontological fossil site located in Mille district, Administrative Zone 1 of the Afar Region, Ethiopia, 15 km upstream (west) of the A1 road's bridge across the Awash River.

<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>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 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.

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">Ronald J. Clarke</span> South African paleoanthropologist

Ronald John Clarke is a paleoanthropologist most notable for the discovery of "Little Foot", an extraordinarily complete skeleton of Australopithecus, in the Sterkfontein Caves. A more technical description of various aspects of his description of the Australopithecus skeleton was published in the Journal of Quaternary Science.

Lucy (<i>Australopithecus</i>) 3.2-million-year-old fossilized hominid

AL 288-1, commonly known as Lucy or Dinkʼinesh, is a collection of several hundred pieces of fossilized bone comprising 40 percent of the skeleton of a female of the hominin species Australopithecus afarensis. It was discovered in 1974 in Ethiopia, at Hadar, a site in the Awash Valley of the Afar Triangle, by Donald Johanson, a paleoanthropologist of the Cleveland Museum of Natural History.

<span class="mw-page-title-main">Little Foot</span> Hominin fossil

"Little Foot" is the nickname given to a nearly complete Australopithecus fossil skeleton found in 1994–1998 in the cave system of Sterkfontein, South Africa.

<span class="mw-page-title-main">Zeresenay Alemseged</span> Ethiopian paleoanthropologist

Zeresenay "Zeray" Alemseged is an paleoanthropologist who is a faculty member at the University of Chicago. In 2013, he was named a Fellow of the American Association for the Advancement of Science. He was elected to the American Academy of Arts & Sciences in 2021. In 2022, he was appointed to the Comité Scientifique International du Musée d’Anthropologie Préhistorique de Monaco and the Pontifical Academy of Science. Alemseged is best known for his discovery, on 10 December 2000, of Selam, also referred to as the "Dikika child" or “Lucy’s child”, the almost-complete fossilized remains of a 3.3 million-year-old child of the species Australopithecus afarensis. The “world’s oldest child”, she is the most complete skeleton of a human ancestor discovered to date. Selam represents a milestone in understanding of human and pre-human evolution and contributes significantly to understanding of the biology and childhood of early species in the human lineage; a subject about which we have very little information. Alemseged discovered Selam while working with the Dikika Research Project (DRP), a multi-national research project funded in part by the National Science Foundation, which he both initiated in 1999 and leads. The DRP has thus far made many important paleoanthropological discoveries and returns to the field each year to conduct further important research. Alemseged's specific research centers on the discovery and interpretation of hominin fossil remains and their environments, with emphasis on fieldwork designed to acquire new data on early hominin skeletal biology, environmental context, and behavior.

The Dikika is an area of the Afar Region of Ethiopia. A hominin fossil named Selam, a specimen of the Australopithecus afarensis species, was found in this area. Papers also propose the earliest evidence of stone tool use at this site in the form of cut marks on animal bone. However there has been argument about this proposal. Dikika is located in Mille woreda.

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>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.

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, hominins left the woodlands that had previously been their natural habitat millions of years ago and adapted to their new habitat by walking upright.

References

  1. "DIK-1-1 (Selam)". www.talkorigins.org. Retrieved 2016-04-12.
  2. Alemseged, Zeresenay; et al. (2006). "A juvenile early hominin skeleton from Dikika, Ethiopia". Nature. 443 (7109): 296–301. Bibcode:2006Natur.443..296A. doi:10.1038/nature05047. PMID   16988704. S2CID   4418369.
  3. Jeremy M. DeSilva; et al. (2018). "A nearly complete foot from Dikika, Ethiopia and its implications for the ontogeny and function of Australopithecus afarensis." Science Advances. Vol 4, Issue 7 DOI: 10.1126/sciadv.aar77
  4. Green, D. J.; Alemseged, Z. (25 October 2012). "Australopithecus afarensis Scapular Ontogeny, Function, and the Role of Climbing in Human Evolution". Science. 338 (6106): 514–517. Bibcode:2012Sci...338..514G. doi:10.1126/science.1227123. PMID   23112331. S2CID   206543814.
  5. Churchill, S. E.; Holliday, T. W.; Carlson, K. J.; Jashashvili, T.; Macias, M. E.; Mathews, S.; Sparling, T. L.; Schmid, P.; de Ruiter, D. J.; Berger, L. R. (11 April 2013). "The Upper Limb of Australopithecus sediba". Science. 340 (6129): 1233477. doi:10.1126/science.1233477. PMID   23580536. S2CID   206547001.