UNESCO World Heritage Site | |
---|---|
Location | Ethiopia |
Part of | Lower Valley of the Awash |
Criteria | Cultural: (ii)(iii)(iv) |
Reference | 10 |
Inscription | 1980 (4th Session) |
Coordinates | 11°6′0.216″N40°34′45.804″E / 11.10006000°N 40.57939000°E |
The Middle Awash is a paleoanthropological research area [1] 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. [2] [3] [4] 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. [5] [6]
A recent find of Australopithecus anamensis is dated to about 4.2 million years ago, which separates it only 200,000 years from an earlier fossil of the more primitive Ardipithecus ramidus (at 4.4 million years ago). Australopithecus garhi fossils are dated as recent as the very early Pleistocene, or 2.5 mya; fossils of Homo erectus in the Daka member at the site (at 1 mya) and Homo sapiens idaltu (at 160 ka ago) are found in the middle and late Pleistocene. And patches of fire-baked clay, disputed as evidences of the controlled use of fire, are also found in that later period. [7]
Sediments at the site were originally deposited in lakes or rivers, and carbonates found there contain low carbon isotope ratios. This information suggests that the environment of the Middle Awash was wet during the late Miocene, and that this currently arid region was occupied then by woodland or grassy woodland habitats. Fossil remains of other vertebrates found with the hominins, including the cane rat, further suggest such an environment. [5] The region was the site of periodic volcanism, which probably created distinct ecological regions inhabited by different species of vertebrate animals. [8]
Important hominin fossils found in the Middle Awash include: [8] [9]
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.
Homininae, is a subfamily of the family Hominidae (hominids). This subfamily includes two tribes, Hominini and Gorillini, both having extant species as well as extinct species.
Orrorin is an extinct genus of primate within Homininae from the Miocene Lukeino Formation and Pliocene Mabaget Formation, both of Kenya.
Australopithecus (, OS-trə-lə-PITH-i-kəs, -loh-; or 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.
Homo is a genus of great ape that emerged from the genus Australopithecus and encompasses only a single extant species, Homo sapiens, along with a number of extinct species classified as either ancestral or closely related to modern humans; these include Homo erectus and Homo neanderthalensis. The oldest member of the genus is Homo habilis, with records of just over 2 million years ago. Homo, together with the genus Paranthropus, is probably most closely related to the species Australopithecus africanus within Australopithecus. The closest living relatives of Homo are of the genus Pan, with the ancestors of Pan and Homo estimated to have diverged around 5.7-11 million years ago during the Late Miocene.
Australopithecus anamensis is a hominin species that lived approximately between 4.3 and 3.8 million years ago and is the oldest known Australopithecus species, living during the Plio-Pleistocene era.
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.
The Hominini (hominins) form a taxonomic tribe of the subfamily Homininae (hominines). They comprise two extant genera: Homo (humans) and Pan, but in standard usage exclude the genus Gorilla (gorillas), which is grouped separately within subfamily Homininae.
Human taxonomy is the classification of the human species within zoological taxonomy. The systematic genus, Homo, is designed to include both anatomically modern humans and extinct varieties of archaic humans. Current humans have been designated as subspecies Homo sapiens sapiens, differentiated, according to some, from the direct ancestor, Homo sapiens idaltu.
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 homininans. 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.
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.
The Gawis cranium is a portion of a fossil hominin skull discovered on February 16, 2006 near the drainage of Gawis, a tributary of the Awash River in the Afar Depression, Ethiopia. Despite the presence of volcanic ash layers that are key to dating, the cranium is only generally dated between 200,000 and 500,000 years ago due to taphonomic issues.
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.
Ardipithecus kadabba is the scientific classification given to fossil remains "known only from teeth and bits and pieces of skeletal bones", originally estimated to be 5.8 to 5.2 million years old, and later revised to 5.77 to 5.54 million years old. 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 6.5–5.5 million years ago. It has been described as a "probable chronospecies" 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.
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.
The Hominidae, whose members are known as the great apes or hominids, are a taxonomic family of primates that includes eight extant species in four genera: Pongo ; Gorilla ; Pan ; and Homo, of which only modern humans remain.
The Bouri Formation is a sequence of sedimentary deposits that is the source of australopithecine and Homo fossils, artifacts, and bones of large mammals with cut marks from butchery with tools by early hominins. It is located in the Middle Awash Valley, in Ethiopia, East Africa, and is a part of the Afar Depression that has provided rich human fossil sites such as Gona and Hadar.
Berhane Asfaw is an Ethiopian paleontologist of Rift Valley Research Service, who co-discovered human skeletal remains at Herto Bouri, Ethiopia later classified as Homo sapiens idaltu, proposed as an early subspecies of anatomically modern humans.
The chimpanzee–human last common ancestor (CHLCA) is the last common ancestor shared by the extant Homo (human) and Pan genera of Hominini. Estimates of the divergence date vary widely from thirteen to five million years ago.
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.