In the genus Homo, us sapiens stand alone today. Once we had an abundance of cousins: Neanderthals, Denisovans, Homo heidelbergensis, Homo erectus and others.
Our isolation makes it easier to assume that hominin history has led up to us — that various lines of human-like primates have evolved, had their chance in the sun and perished, leaving their more human-like descendants to approach the form of modern humans.
Rudolph Zalliger’s infamous artwork The Road to Homo Sapiens, now more commonly known as The March of Progress, is commonly blamed for creating this perception in the minds of the public, though that was not what Zalliger himself intended.
But when paleontologists and anthropologists look back at the history of hominin evolution, they find a veritable Gordian Knot, one that weaves back into itself, with innumerable dead ends. For a clear example, consider our quest to learn who the ancestors of our closest relatives, the Neanderthals and Denisovans, were.
