
On the ride up to Adgantole, we stopped at the Ardi skeleton site itself, on a flat wash below the road, about the size of a tennis court. The excavation was covered by a large mound of stones. The place was silent now, but I could imagine the shouts of excitement as each bone—125 of them in all—peeked out from the earth or later emerged from its plaster jacket in the museum.There were no eureka moments, White told me sternly, later, when he was able to talk more freely about the skeleton. Then he described half a dozen of them. One came when he removed the plaster around a little foot bone called the medial cuneiform, which articulates with the base of the big toe. In humans and all other hominids, the joint surface of this bone is oriented so that the big toe lines up with the others, providing a strong toe off for an effective bipedal stride. In apes the joint surface points in a different direction, so that the big toe can pull away from, and grasp against, the other toes to grip on to tree limbs. In this key feature, Ardi was like an ape. Yet in other respects her foot was nothing like an ape at all, bearing characteristics that would enable her to walk upright.Everywhere the scientists looked, they found a similarly bizarre mosaic of traits: some very primitive, others advanced and exclusive to hominids. Ardi wasn’t just another biped, or just another quadruped. Ardi was both.I asked White whether Ardi’s transitional form might justify calling Ar ramidus a missing link He bristled at the very question.
