Kenyan Fossils Rekindle Debate over Early Human Diversity

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http://blogs.scientificamerican.com/observations/2012/08/09/kenyan-fossils-rekindle-debate-over-early-human-diversity/


The KNM-ER 1470 cranium, discovered in 1972, combined with the new lower jaw from Koobi Fora. The specimens are thought to belong to the same species. The lower jaw is shown as a photographic reconstruction, and the cranium is based on a computed tomography scan. © Photo by Fred Spoor

If I had to pick the hottest topic in paleoanthropology right now, I’d say it’s the origin and early evolution of our genus, Homo. Researchers know quite a bit about our australopithecine predecessors (Lucy and her ilk) and about later phases of Homo’s evolution. But the dawn of our lineage is cloaked in mystery. One question experts have long puzzled over is whether Homo split into multiple lineages early on, or whether the known early Homo fossils all belong to a single lineage. To that end, new discoveries made at the site of Koobi Fora in northern Kenya—one of the Leakey’s longtime fossil hunting grounds—are said to settle that matter in favor of multiple lineages. But some critics disagree.

The new finds—a partial face including almost all of the molars in the upper jaw, a nearly complete lower jaw and a partial lower jaw that date to between 1.78 million and 1.95 million years ago—bear on the identity of a famously enigmatic skull from Koobi Fora known as KNM-ER 1470. Ever since the discovery of the 1470 skull in 1972, researchers have struggled to place it in the human family tree. On one hand, at nearly two million years old it is the same age as H. habilis fossils from Koobi Fora and other locales in East Africa. The skull also shares some features in common with that species, which most researchers consider to be the founding member of Homo. On the other hand, 1470 is much larger than established H. habilis fossils, and differs from them in having a flat, long face, among other distinctive traits. Some experts thus assigned 1470 and some other fossils from Koobi Fora to a separate species, H. rudolfensis.

[HopeHoops]

1. How long before Trump jumps on this?