In 2005, near the small town of Dmanisi, Georgia, a 1.8 million-year-old skull was discovered by the anthropologist David Lordkipanidze. The skull was not the first archeological finding uncovered in the area, but in fact was the most recent of five skulls, all said to be from the same era. The skull, simply named Dmanisi skull 5, is the most complete skull specimen of a Pleistocene Homo species, and the oldest complete adult hominin skull found to date. What is truly groundbreaking about the discovery, however, is that it provides evidence to suggest that two species of early hominins, Homo rudolfensis and Homo habilis, are actually both subspecies of Homo erectus. Furthermore, the discovery also implies that the Homo erectus georgicus ventured out of Africa as far back as 1.85 million years ago, hundreds of thousands of years earlier than anthropologists had previously thought.
Naturally, the skull has been the cause of a paleontological controversy, one still going on today. While these findings are quite compelling, even Lordkipanidze himself admits that his interpretation of the Dmanisi discoveries is far from certain. Skeptics tend to point to the clear differences between the skulls of Dmanisi and the skull structure of Homo erectus. They note that the Dmanisi skulls are smaller and rounded instead of angled at the back, which is reminiscent of the earlier species, Homo habilis, which appeared in Africa two million years ago. Those who support the notion of a single lineage mention the multiple features of the Dmanisi skulls, particularly skull 5, which resemble those of classic homo erectus fossils. These features include straight brow ridges, a line of heavy bone running front-to-back across the top of the skull, and the shape of the nasal cavity. Although there has yet to be a clear agreement regarding the meaning of these findings, it is clear that the long-held notions as to which of our ancestors first left Africa, when they left, and why, have been challenged.
It can be assumed based on the passage that
A. the discovery concerns the natural sciences.
B. skull 5 represents a less advanced species than the other four skulls.
C. the Dmanisi skull 5 belongs to a Homo erectus.
D. the scientific community will likely never come to an agreement regarding the Dmanisi skulls.
E. the author believes that Homo erectus left Africa as early as 1.85 million years ago.