October 1, 2009

Ardipithecus ramidus

Scientists Unveil the Reconstructed “Ardi” Skeleton and Ardipithecus Studies

The discovery announced in 2009 had begun with a hand bone 15 years earlier, and the skeleton came out of the ground in 125 fragments.

Two press conferences, two continents

On 1 October 2009 an international team announced its reconstruction and analysis of the partial Ardipithecus ramidus skeleton ARA-VP-6/500 — nicknamed “Ardi” — at simultaneous press conferences in Washington, D.C., and Addis Ababa.

The announcement previewed 11 papers by 47 scientists from 10 countries in the 2 October issue of Science, covering the skeleton, other Ar. ramidus remains, geological dating, habitat, and associated animal and plant fossils.

They described a roughly 4.4-million-year-old individual, probably female, combining arboreal climbing adaptations with a more primitive form of terrestrial bipedalism than that of Australopithecus.

Fifteen years between the bone and the announcement

This was not the day the fossil was found. Yohannes Haile-Selassie found the hand bone that led the team to the skeleton in 1994, and excavation ran over three field seasons. The species was not new either: fragmentary Ar. ramidus fossils were first published in 1994 and the genus Ardipithecus was established in 1995.

The bones were so fragile that researchers molded them in place and lifted them in plaster jackets; Gen Suwa reconstructed the skull from 5,000 micro-CT slices.

The wider assemblage included 110 other catalogued Ar. ramidus specimens representing at least 36 individuals, plus more than 150,000 plant and animal fossils used to rebuild the woodland environment.

What the team claimed, and what it didn't

Ardi was presented as the oldest relatively complete hominin skeleton, not the oldest hominin remains. Older and far more fragmentary candidates — Sahelanthropus, Orrorin, Ardipithecus kadabba — were already known.

The researchers argued that her anatomy undermined treating modern chimpanzees as unchanged models for the human–ape last common ancestor. Ardi was not identified as that ancestor, and Ar. ramidus's phylogenetic position and status as a direct human ancestor remain disputed.

Her sex is inferred rather than genetically demonstrated, some locomotor reconstructions are contested because the pelvis was crushed and incomplete, and the pair-bonding and male-provisioning ideas attached to the find were hypotheses C. Owen Lovejoy derived largely from canine anatomy.

Sources

Researched 24 Aug 2026 7 sources not yet audited Date disputed

How this was checked

Researched from the web into a fact sheet and rewritten from that sheet. This article has not yet had an independent model audit. How the pipeline works →

Date disputed. Sources disagree about when this happened.

What the sources leave uncertain

The 1 October date is solid for the press conferences and online unveiling; the print issue of Science is dated 2 October 2009.
Ardi’s sex is inferred, not genetically demonstrated.
The research team classified Ar. ramidus as a basal hominin and a possible ancestor or close relative of Australopithecus. Its exact phylogenetic position and status as a direct human ancestor remain disputed.
The team called Ardi the oldest known hominin skeleton, meaning a substantially represented skeleton—not the oldest hominin fossil remains. Older, much more fragmentary candidates such as Sahelanthropus, Orrorin, and Ardipithecus kadabba were already known.