A stunning fossil recently unearthed is being hailed as a major find in the world of paleontologists. Scientists and researchers are shocked and thrilled to find out that human evolution may have just been turned on its skull, literally. The skull was uncovered in the Georgian town of Dmanisi and it may mean that we humans will have to say goodbye to numerous species within the course of evolution, including H habilis, H ergaster, H gautengensis, and H rudolfensis. The new study has been published recently in the journal Science and is entitled A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo.
Scientists say the aforementioned species may not be different species at all, but simply different-looking versions of H erectus. This would mean wiping out the work of many archaeologists over the years who may not have had the same reference points as are now available with this skull find. Researchers think the human ancestor to whom the skull belonged met a bloody and tragic end; he was most likely eaten by carnivorous animals along with four additional companions, they say. The remains of the other ancestors were also uncovered at the site in the den of a carnivore. The den had collapsed in upon itself. The bones have remained; a sad burial for human ancestors who had an unimaginably difficult and dangerous life.
Georgian National Museum scientist David Lordkipanidze explains how earlier researchers may have come to the conclusion that previous skulls had each belonged to an entirely separate species: “If you found the Dmanisi skulls at isolated sites in Africa, some people would give them different species names. But one population can have all this variation. We are using five or six names, but they could all be from one lineage,” he said.
In layperson’s terms, the skull has raised so much excitement because researchers have discovered that it represents a normal variation in appearance of an H erectus skull. Previously, these normal variations among H erectus skulls were thought to be totally distinct species which were given their own names.
An analogy we could use to understand this is if scientists in the future uncovered two human skulls which had normal variations and misunderstood them to be of two different species altogether. Scientists are so excited about the discovery because the skull is one of the earliest and best-preserved ever found; in fact, it is the only complete skull of such an early ancestor. The study authors say it is “the world’s first completely preserved adult hominid skull.”
Scientists warn that not everyone will accept the findings outright and that the skull could prove to be very controversial within the paleontology community. While some researchers are very confident in the theory that the skull represents a variation of an H erectus skull, others are more cautiously optimistic.
Chris Stringer, who works at the Natural History Museum in London and heads up the human origins department explains:
I think they will be proved right that some of those early African fossils can reasonably join a variable Homo erectus species. But Africa is a huge continent with a deep record of the earliest stages of human evolution, and there certainly seems to have been species-level diversity there prior to two million years ago. So I still doubt that all of the ‘early Homo’ fossils can reasonably be lumped into an evolving Homo erectus lineage. We need similarly complete African fossils from two to 2.5m years ago to test that idea properly.
Stringer is not alone in his feeling that more research is needed. Some scientists have said that they believe the skull actually belongs to another well-known, previously established species: H habilis. One scientist, Lee Berger, who works at the University of the Witwatersrand says the find is definitely important, but that the study authors may be jumping the gun at this point in the discovery process. “The specimen is wonderful and an important contribution to the hominin record in a temporal period where there are woefully too few fossils,” he wrote in an email to CNN, “But the suggestion that these fossils prove an evolving lineage of Homo erectus in Asia and Africa (is) taking the available evidence too far.” Another expert, Ian Tattersall, says he has no doubt that the find has been inflated beyond its actual significance and says that there is “no way this extraordinarily important specimen is Homo erectus.”
However, many paleontologists think this is an extremely significant moment in their field and say the importance of the find “cannot be overstated.”
The journal abstract explains that the skull is 1.8 million years old and that it represents evidence that the H erectus species represented more variations in appearance than has been previously thought:
The site of Dmanisi, Georgia, has yielded an impressive sample of hominid cranial and postcranial remains, documenting the presence of Homo outside Africa around 1.8 million years ago. (The skull) combines a small braincase…with a large prognathic face and exhibits close morphological affinities with the earliest known Homo fossils from Africa. The Dmanisi sample, which now comprises five crania, provides direct evidence for wide morphological variation within and among early Homo paleodemes. This implies the existence of a single evolving lineage of early Homo, with phylogeographic continuity across continents.
In addition to the skull find, scientists at the site found evidence that the human ancestors and carnivorous animals may have been engaged in combat over the carcasses of other deceased animals, and that the ancestors used tools fashioned out of stone to slice and dice the carcasses.
Most paleontologists would most likely not argue with the statement that more research is needed. However, the discovery has already led to discussions about the massive changes that will need to be made to textbooks and even museum displays around the world if the find turns out to be validated by future studies. Human evolution may get turned on its skull after the find in Dmanisi, but if it is verified by future research, it will end up greatly simplifying the history of our ancestral lineage.
By: Rebecca Savastio