Human Evolution XI: Australopithecus garhi
By Sailko - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=89662026
Living about 2.6-2.5 million years ago, Australopithecus garhi (garhi meaning 'surprise' in the Afar language) lived in the Afar Region of Ethiopia during the early part of the Pleistocene. They were adapted to both living among the trees and walking bipedally like other Australopithecus species, though they have longer legs, possibly indicating a 'delayed adolescent growth spurt' more like modern humans than modern non-human apes, which don't experience such growth spurts. Though this could also mean they either matured more slowly than non-human apes or that their legs grew more rapidly than the rest of their body. Research is still on-going.
When they were described in 1999, there weren't many hominin remains from between about 3-2 million years ago, with the only identified species being A africanus and Paranthropus aethiopicus. The researchers concluded that A garhi was an offshoot rather than a direct ancestor because of the lack of shared traits between the Homo genus and A garhi.
Source: https://www.nature.com/articles/nature09248
What makes A garhi interesting is that they might have been the first hominin to use tools. Bones found near them show cut and percussion marks with a bovid mandible showing 'three successive, unambiguous cut marks presumably made while removing the tongue; a bovid tibia with cut marks, chop marks, and impact scars from a hammerstone, possibly inflicted to harvest the bone marrow; and a Hipparion (a horse) femur with cut marks consistent with dismemberment and filleting'. Though the stone tools haven't been found, its thought that this is because the region where the bones were found was a 'grassy lake margin with so few raw materials for making stone tools, it is possible these hominins were created and carrying tools some ways with them to butchering sites, intending to use them many times before discarding', though they also might have just collected naturally sharp rocks and used those. A nearby site, Gona, where there are a lot of raw materials, there are tools that date to about 2.6-2.5 million years ago, when A garhi would have been the only hominin in the area, making them likely the first tool makers in the area. While more recent finds have shown possible cut marks earlier, the cut marks associated with A garhi are the oldest unambiguous cut marks that we know of. The oldest tool making site we've discovered at Lomekwi dates back to 3.3 million years ago, predating A garhi by 700,000 years. There is still a lot of research and debate ongoing about this site, and which hominin made them.
