Living between 2.3 million and 1.4 million years ago across Tanzania, Ethiopia and Kenya, Paranthropus boisei thrived for about 1 million years. Unfortunately we have yet to uncover any specimens for the body or limbs, but we do have a few specimens of the skull, jaw and teeth that indicate how fascinating this species was.
Boisei is nicknamed "nutcracker man" because of its large teeth and strong jaws. However, wear on the teeth suggests that although they could chew hard foods, they commonly didn't. The skull is short from front to back but has wide cheekbones and wide eye sockets. The fact that boisei's face didn't project as much as earlier hominid species suggests a progression toward more humanlike characteristics.
Another significant aspect of this find was that it marked the first use of a method called potassium/argon (K/Ar) dating for determining the age of volcanic ash. This was helpful because volcanic ash covered the surface, forming a lasting layer. When we discover fossils in between layers, we can reliably narrow down the age of those fossils. And, in some cases, volcanic ash even captured and preserved footprints of ancient hominids. After this development, paleoanthropologists found that the process of human evolution is far older and longer than previously believed.
In addition, the discovery that boisei lived at the same time as Homo erectus helped paleoanthropologists determine that the history and lineage of hominids was not a straight line but a tree with various branches [source: Smithsonian].