Johanson, Donald C. (1943–)

Contributions and Perspectives

Johanson's most significant contribution was the discovery and interpretation of the fossil hominid, which he named Australopithecus afarensis. Although his first discovery was dubbed “Lucy” during the excavation, the Hadar collection AL 288–1 would prove to be a single specimen that challenges the traditional taxonomical sequence of the human evolutionary line.

Discovered during what could be considered the latter half of the great hominid discoveries, in the early 1970s, Johanson set out to search for fossil hominids in Hadar, Africa. The area of Hadar was perfect for recovering fossils. Hadar was once an ancient lake bed that is now rock, sand, and gravel. Due to the soil's inability to absorb rainfall, runoff tends to erode the soil, uncovering fossils that lie underneath. Johanson's first field season at Hadar yielded a proximal tibia, a condyle, and a distal femur. Johanson quickly realized the relationship among the three specimens; discounting human or monkey remains, the knee joint specimen had to be a fossil hominid. Confirmed by Mary and Richard Leakey, this knee joint was the first to be analyzed by anthropologists. An early estimated age of 3 to 4 million years gave Johanson proof of the oldest bipedal specifmen to date, causing debates and a reanalysis of hominid phylogeny.

Although the initial description of this small bipedal creature (for the analysis was far from complete) had yet to gain acceptance by the scientific community represented at the Wenner-Gren conference, the prospect of new hominid began to stir interest. During Johanson's second expedition to Hadar, he found Lucy at Locality 162. Lucy was described as a three-and-a-half-foot-tall, bipedal hominid with a small brain. Unlike larger jaws found at the site, Lucy's jaw was V-shaped with one cusp premolar. This fact led Johanson to believe that Lucy was an early representative of australopithecines. This find would only be outdone by the discoveries that followed during the next season.

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