Journal Article

Asa Issie, Aramis and the origin of Australopithecus

Wesselman, Hank, Beyene, Yonas, Hlusko, Leslea J., Hart, William K., Lovejoy, C. Owen, Currie, Brian, Suwa, Gen, Asfaw, Berhane, Louchart, Antoine, WoldeGabriel, Giday, Ambrose, Stan, Kono, Reiko T., Saegusa, Haruo, Gilbert, Henry, Vrba, Elisabeth S., Bernor, Raymond L., Lehmann, Thomas, White, Tim D., Renne, Paul R., Boisserie, Jean-Renaud, Howell, F. Clark, Haile-Selassie, Yohannes

2006

Overview

The origin of Australopithecus , the genus widely interpreted as ancestral to Homo , is a central problem in human evolutionary studies. Australopithecus species differ markedly from extant African apes and candidate ancestral hominids such as Ardipithecus , Orrorin and Sahelanthropus . The earliest described Australopithecus species is Au . anamensis , the probable chronospecies ancestor of Au . afarensis . Here we describe newly discovered fossils from the Middle Awash study area that extend the known Au . anamensis range into northeastern Ethiopia. The new fossils are from chronometrically controlled stratigraphic sequences and date to about 4.1–4.2 million years ago. They include diagnostic craniodental remains, the largest hominid canine yet recovered, and the earliest Australopithecus femur. These new fossils are sampled from a woodland context. Temporal and anatomical intermediacy between Ar. ramidus and Au . afarensis suggest a relatively rapid shift from Ardipithecus to Australopithecus in this region of Africa, involving either replacement or accelerated phyletic evolution. Australopithecus before Lucy Humanity is widely believed to have descended from the genus Australopithecus , but the beginnings of that genus are shrouded in mystery. Newly discovered fossils from a previously unsampled time slice in the Middle Awash study area of Ethiopia add important information on the subject. They represent the earliest known member of the genus, Australopithecus anamensis , the first to be found outside the Turkana basin in Kenya. The finds are from a woodland context and show how Australopithecus may have evolved from the more primitive Ardipithecus , and may have been ancestral to Australopithecus afarensis , popularly known as ‘Lucy’. Newly recovered Ethiopian fossils of Australopithecus anamensis show how Australopithecus might have evolved from the earlier and more primitive genus Ardipithecus , and might have been a harbinger of Australopithecus afarensis , better known as ‘Lucy’.

• Publisher: Nature Publishing Group UK,Nature Publishing,Nature Publishing Group
• Subject: Animals / Biological Evolution / Dentition / Earth Sciences / Earth, ocean, space / Environment / Ethiopia / Evolution / Exact sciences and technology / Femur - anatomy & histology / Fossils / Geography / History, Ancient / Hominidae - anatomy & histology / Hominidae - classification / Hominidae - physiology / Hominids / Humanities and Social Sciences / multidisciplinary / Paleontology / Phylogeny / Science / Science (multidisciplinary) / Sciences of the Universe / Time Factors / Vertebrate paleontology / Woodlands