New Skull Fossil Has Scientists Rethinking Human Evolutionary History

by bisonmessink

A 1.8 million-year-old humanoid skull unearthed in the republic of Georgia has scientists rewriting their theories of human evolution.

The fossil known as “Skull 5” is the most completely preserved of its kind, and suggests to scientists that the lineage of human ancestors may be shorter than previously believed, with more variation within the each species as they evolved.

Variations in the brain cases and facial features of previous African skull fossils had led scientists to believe that the fossils had come from separate species, while Skull 5, found in Dmanisi, Georgia, tells scientists that there may simply have been more variation within the same species, much as two humans might look vastly different today. Or, to put it in unscientific terms, maybe some of the human ancestors were just uglier than we’d thought.

“Since we see a similar pattern and range of variation in the African fossil record,” Dr. Christopher Zollikofer, of the University of Zurich, told the New York Times, “it is sensible to assume that there was a single Homo species at that time in Africa.” And, he continued, “since the Dmanisi hominids are so similar to the African ones, we further assume that they both represent the same species.”

The conclusion of fewer species/more variation isn’t unanimously held by the scientific but regardless, Skull 5 is being hailed as “undoubtedly one of the most important ever discovered.”

More from the Times:

In their report, the Dmanisi researchers said the Skull 5 individual “provides the first evidence that early Homo comprised adult individuals with small brains but body mass, stature and limb proportions reaching the lower range limit of modern variation.”

Skeletal bones associated with the five Dmanisi skulls show that these hominids were short in stature, but that their limbs enabled them to walk long distances as fully upright bipeds. The shape of the small braincase distinguished them from the more primitive Australopithecus genus, which preceded Homo and lived for many centuries with Homo in Africa.