Overview:

This species is not well documented; it is defined on the basis of one fossil cranium and four other skull fragments, although a partial skeleton found nearby, from about the same layer, is usually included as part of the Australopithecus garhi sample. The associated fragmentary skeleton indicates a longer femur (compared to other Australopithecus specimens, like ‘Lucy’) even though long, powerful arms were maintained. This suggests a change toward longer strides during bipedal walking.

History of Discovery:

The human fossil record is poorly known between 3 million and 2 million years ago, which makes the finds from the site of Bouri, Middle Awash Ethiopia, particularly important. First in 1990 and then from 1996 to 1998, a research team led by Ethiopian paleoanthropologist Berhane Asfaw and American paleoanthropologist Tim White found the partial skull (BOU-VP-12/130) and other skeletal remains of an early humans dated to around 2.5 million years old. In 1997, the team named the new species Australopithecus garhi; the word ‘garhi’ means ‘surprise’ in the Afar language.

How They Survived:

Fossils of Australopithecus garhi are associated with some of the oldest known stone tools, along with animal bones that were cut and broken open with stone tools. It is possible, then, that this species was among the first to make the transition to stone toolmaking and to eating meat and bone marrow from large animals.

Evolutionary Tree Information:

Some scientists claim that the large molar teeth show that Australopithecus garhi is related to Paranthropus aethiopicus; however, the combination of features of the face, braincase, and teeth are unlike Paranthropus. The scientists who originally reported the finds think that Au. garhi may represent an ancestor of the genus Homo.

Questions:

We don’t know everything about our early ancestors—but we keep learning more! Paleoanthropologists are constantly in the field, excavating new areas with groundbreaking technology, and continually filling in some of the gaps about our understanding of human evolution.

Below are some of the still unanswered questions about Australopithecus garhi that may be answered with future discoveries:

1. Will scientists recover more individuals from this species? Until they do, it is hard to determine exactly where this species fits on the human family tree.
2. Did Au. garhi actually make and use the stone tools found nearby?
3. Is it possible the Au. garhi skull BOU-VP-12/130 is really a female Paranthropus aethiopicus or a late Australopithecus afarensis specimen?

References:

First paper: 

Asfaw, B., White, T., Lovejoy, O., Latimer, B., Simpson, S., Suwa, G., 1999. Australopithecus garhi: a new species of early hominid from Ethiopia. Science 284, 629-635.