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Day 20 (July 15, 2011): Further Update from Olorgesailie

July 15, 2011

one man carefully cleans a fossil with a brush while another man watches over his shoulder
Mativo carefully cleans a fossil mandible with a brush while teaching one of the younger crew members
Back at Olorgesailie, excavations were continuing. The BOK-2 team carried out their second lift this week – lots of stuff is coming out of the ground there. Near the end of the day, Mativo unearthed the most interesting fossil from this excavation so far. In an area dense with stone artifacts, he brushed away some dirt he had loosened and spotted the surface of a bone. With fine tools he meticulously pried away grains of dirt, little by little, uncovering a fragment of lower jaw with a row of teeth of an antelope. Although hundreds of fossilized bone fragments have come from this dig over the years, most are too fragmented to identify. This one’s interesting because it can tell us the specific type of animal that lived near the site – perhaps one that the Middle Stone Age toolmakers had hunted and carried to the site.

a man holds in a small set of fossil teeth in a partial mandible in one hand and applies a few drops of glue to repair a crack
Mativo applies a small amount of glue to help repair a crack in the surface of the fossil mandible. It’s important we use glue that perfectly preserves the surfaces of fossils and will last for as long as the fossil collections themselves
After taking great care, we were able to lift the fossil from the ground, place it in tissue paper and wrap it again in aluminum foil for extra protection. Back at camp, we’ll temporarily unwrap the fossil to make a further evaluation. From what it sounds like, the mandible belongs to a species of antelope, or bovid as it is known scientifically, that typically lives off of bushy vegetation. In other words, it usually prefers to eat the leaves of low-lying shrubs and to live in places with abundant shrubs and trees. One of the scientific questions we always pursue in our work concerns the habitats where early human ancestors lived. The mandible, and we expect other fossils we find at the BOK-2 excavation, will help us figure out more about the past environment of this site.

Two blueish gray teeth in part of antelope's lower jaw with some brown matrix still attached, approximately 5 cm in length
Two of the teeth (right side of the image) in part of the lower jaw found at the BOK-2 excavation. The surfaces of the teeth, unlike those of a carnivore, allowed this antelope to easily chew leaves and other vegetation
As the excavation continues, it will be interesting to see if more fossils from the same individual will be found. The limbs bones, for example, can help us determine if there were butchery marks, where meat was cut off using stone tools – and that will tell us how the remains of this particular animal ended up at this site.