Australopithecus anamensis

Taxobox | name = "Australopithecus anamensis"
fossil_range = Pliocene


regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = Primates
familia = Hominidae
subfamilia = Homininae
genus = "Australopithecus"
species = "A. anamensis"
binomial = "Australopithecus anamensis"
binomial_authority = Leakey et al., 1995

"Australopithecus anamensis" is a fossil species of "Australopithecus". The first fossilized specimen of the species, though not recognized as such at the time, was a single arm bone found in Pliocene strata in the Kanapoi region of East Lake Turkana by a Harvard University research team in 1965. The specimen was tentatively assigned at the time to "Australopithecus" and dated about four million years old. Little additional information was uncovered until 1987, when Canadian archaeologist Allan Morton (with Harvard University's Koobi Fora Field School) discovered fragments of a specimen protruding from a partially eroded hillside east of Allia Bay, near Lake Turkana, Kenya. Six years later the London-born Kenyan paleoanthropologist Meave Leakey and archaeologist Alan Walker excavated the Allia Bay site and uncovered several additional fragments of the hominid, including one complete lower jaw bone which closely resembles that of a common chimpanzee "(Pan troglodytes)" but whose teeth are much more similar to those of a human. In 1995, Meave Leakey and her associates, taking note of differences between "Australopithecus afarensis" and the new finds, assigned them to a new species, "A. anamensis", deriving its name from the Turkana word "anam", meaning "lake". [cite journal | author = M. G. Leakey, C. S. Feibel, I. MacDougall & A. Walker | date = 1995-08-17 | title = New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya | journal = Nature | volume = 376 | issue = 6541 | pages = 565–571 | doi = 10.1038/376565a0]

Although the excavation team did not find hips, feet or legs, Meave Leakey believes that "Australopithecus anamensis" often climbed trees. Tree climbing was one behavior retained by early hominins until the appearance of the first "Homo" species about 2.5 million years ago. "A. anamensis" shares many traits similar to "Australopithecus afarensis" and may as well be its direct predecessor. "A. anamensis" is thought to have lived from 4.1 and 3.9 million years ago. The older specimens were found between two layers of volcanic ash, dated to 4.17 and 4.12 million years, coincidentally when "A. afarensis" appears in the fossil record.

The fossils (twenty one in total) include upper and lower jaws, cranial fragments, and the upper and lower parts of a leg bone (tibia). In addition to this, a fragment of humerus that was found thirty years ago at the same site at Kanapoi has now been assigned to this species.

In 2006, a new "A. anamensis" find was officially announced, extending the range of A. anamensis into north east Ethiopia. These new fossils, sampled from a woodland context, include the largest hominid canine yet recovered and the earliest Australopithecus femur. [cite journal | author = White, Tim D., et al | journal = Nature | volume = 440 | issue = 7086 | pages = 883–889 | date = 2006-04-13 | doi = 10.1038/nature04629 | title = Asa Issie, Aramis and the origin of "Australopithecus"] The find was in an area known as Middle Awash, home to several other more modern "Australopithecus" finds and only six miles away from the discovery site of "Ardipithecus ramidus", the most modern species of "Ardipithecus" yet discovered. "Ardipithecus" was a more primitive hominid, considered the next known step below "Australopithecus" on the evolutionary tree. The "A. anamensis" find is dated to about 4.2 million years ago, the "Ar. ramidus" find to 4.4 million years ago, placing only 200,000 years between the two species and filling in yet another blank in the pre-"Australopithecus" hominid evolutionary timeline.cite web | title = New Fossil Links Up Human Evolution | last = Borenstein | first = Seth | url = http://hosted.ap.org/dynamic/stories/H/HUMAN_EVOLUTION?SITE=SCBMN&SECTION=HOME&TEMPLATE=DEFAULT | publisher = The Associated Press | accessdate = 2006-04-13]

References

See also

* List of fossil sites "(with link directory)"
* List of hominina (hominid) fossils "(with images)"

External links

* [http://www.archaeologyinfo.com/australopithecusanamensis.htm (ArchaeologyInfo.com) C. David Kreger, "Australopithecus anamensis"]
* [http://www.pbs.org/wgbh/evolution/humans/humankind/c.html PBS Origins of Humankind]
* [http://news.yahoo.com/s/livescience/20070717/sc_livescience/possiblelinktolucysancestorsfound Article about 2007 discovery] (July 2007)