Overview:

Very little is known about Kenyanthropus platyops—a flat-faced, small-brained, bipedal species living about 3.5 million years ago in Kenya. Kenyanthropus inhabited Africa at the same time as Lucy’s species Australopithecus afarensis, and could represent a closer branch to modern humans than Lucy’s on the evolutionary tree. Before the discovery of the only known skull of this species in 1999, the earliest fossil evidence known for a flat-faced early human, a significant shift in skull structure, was around 2 million years ago.

History of Discovery:

Working in the Lake Turkana region of northern Kenya in 1998 and 1999, a research team led by scientist Meave Leakey found a cranium and other fossil remains of a 3.5 million year old early human that has a mixture of features unseen in other early human fossils. Noting the unusual combination of traits, Leakey and her team named a new genus and species, Kenyanthropus platyops, or “flat-faced human from Kenya.”

How They Survived:

While Kenyanthropus lived at the same time as Australopithecus afarensis, Kenyanthropus’ molars were smaller, indicating that the two species may have had different diets and therefore likely did not compete for the same types of food, though they were both probably largely plant eaters.

Evolutionary Tree Information:

Before the discovery of Kenyanthropus, only a single early human species, Australopithecus afarensis, had been found in East Africa between 4 million and 3 million years ago. The existence of Kenyanthropus reflects a diversity of early human species living at the same time. Many scientists think A. afarensis is the ancestor of the Homo species and therefore modern humans, but some scientists now feel Kenyanthropus’ flat face and less-pronounced brow ridges seem more closely related to Homo.

Others in the scientific community believe more fossil evidence is needed before we can place Kenyanthropus within our family tree, as the only known skull from the species was found badly distorted.  These scientists believe Kenyanthropus platyops is no more than a variant of Au. afarensis.

Kenyanthropus platyops is so far the only species belonging to the Kenyanthropus genus.

Questions:

We don’t know everything about our early ancestors—but we keep learning more! Paleoanthropologists are constantly in the field, excavating new areas with groundbreaking technology, and continually filling in some of the gaps about our understanding of human evolution.

Below are some of the still unanswered questions about Kenyanthropus platyops that may be answered with future discoveries:

1. How large were Kenyanthropus platyops individuals? Was there a big difference between the sizes of males and females?
2.  Is Kenyanthropus platyops more closely related to modern humans than Australopithecus afarensis (Lucy’s species)?
3. Does KNM-WT 40000 actually represent a new genus and species, or are its unique skull traits a result of distortion caused by depositional process?
4. What gender was KNM-WT 400000? Its small teeth resemble those of a female, but the temporal lines on the skull reflect larger chewing muscles more similar to many early human males.
5. KNM-WT 40000 resembles KNM-ER 1470, another flat-faced early human skull usually attributed to the Homo rudolfensis. Was Kenyanthropus platyops the ancestor of Homo rudolfensis?

References:

First paper:

Leakey, M.G., Spoor, F., Brown, F.H., Gathogo, P.N., Kiarie, C., Leakey, L.N., McDougall, I., 2001. New hominin genus from eastern Africa shows diverse middle Pliocene lineages. Nature 410, 433-440.

Other recommended readings: 

Lieberman, D.E., 2001. Another face in our family tree. Nature 410, 419-420.

Schwartz, J.H., White, T.D., 2003. Another perspective on hominid diversity. Science 301, 763-764.

White, T.D.,  2003. Paleoanthropology: Early hominids - Diversity or distortion? Science 299, 1994.