Thread by @johnhawks

Occasionally fossil hominin remains show us direct evidence of ancient behaviors. A recent paper by @AEstalrrich highlights the evidence that the famous "Lucy's Child" specimen from Olduvai Gorge, OH 62, used toothpicks. doi.org/10.1016/j.jhev… #FossilFriday

OH 62 is a fragmented partial skeleton. Tim White discovered the first pieces in 1986, and since the 1987 description by team leader Donald Johanson and coworkers, most have regarded it as Homo habilis. The extreme fragmentation makes it challenging to understand.

For their new study, @AEstalrrich and collaborators examined tiny tooth fragments, identifying two with distinct grooves. Under the microscope, they were able to show the striations from back-and-forth wear, probably from pieces of straw.

@AEstalrrich Toothpick grooving in very common in recent human populations from many parts of the world. This is a table from a 1998 paper by Christy Turner and Erin Cacciatore collecting data on 10,000 skulls. doi.org/10.1537/ase.10…

Another early hominin specimen with such grooves is Omo L.894-1, from southern Ethiopia around 1.8 million years old. Boaz and Howell (1977) showed the grooves, later experimental work by @LHlusko showed how toothpicking with grass stems could make them. doi.org/10.1086/379263