Skulls Unearthed in Georgia Radically Simplify Homo Sapiens Lineage
In 1991, archaeologists unearthed traces of proto human habitation in a cave near Dmanisi, Georgia. In subsequent years, five early Homo erectus hominid skulls, whose owners lived about 1.75 million years ago, were dug up. The last of them, unearthed in 2005 and known as Skull 5, is the world’s most completely preserved skull of an adult hominid discovered to date. It is not just a well preserved fossil, however: Skull 5 and its companions from the Dmanisi cave might end up rewriting the evolutionary lineage of mankind.
Hominids have long been classified into a variety of species, such as Homo habilis, Homo erectus, and Homo rudolfensis, based on differences and variations in their features, as seen in their fossils. Those different species mean that the evolutionary lineage of modern humans is relatively complex, with a family tree containing various branches and sub branches. Some lead to us, while other branches went extinct.
However, what if those different species were not actually different species at all, but members of the same species? The five Dmanisi skulls are sufficiently different from one another that, if they had been discovered in different locations, they would have been classified as belonging to different species. However, scientists know from the context and surroundings in which they were discovered, that the five Dmanisi skulls belonged to members of the same species.
The conclusion drawn from those differences and variations, seen within members of the same hominid species, might radically upend our understanding of hominid lineages. The Dmanisi skulls demonstrate that early hominids had variations and differences in appearance between members of the same species, just like modern humans have variations and differences in appearance between each other.
That being so, it casts in doubt the grounds for classifying early hominids into different species, such as Homo erectus, Homo habilis, and Homo rudolfensis, based on the observed differences and variations in their fossils. What if those skulls do not belong to different species, but to a single species whose individuals, as with the Dmanisi skulls, or as with modern humans, simply have a variety of appearances?