Kenyanthropus platyops is a 3.5 to 3.2 million year old (Pliocene) hominin fossil that was discovered in Lake Turkana, Kenya in 1999 by Justus Erus, who was part of Meave Leakey's team.  Leaky (2001) proposes that the fossil represents an entirely new hominine genus, while others classify it as a separate species of Australopithecus, Australopithecus platyops, and yet others interpret it as an individual of Australopithecus afarensis.
Discovery and interpretations
The fossil found features a broad flat face with a toe bone that suggests it probably walked upright. Teeth are intermediate between typical human and typical ape forms. Kenyanthropus platyops, which means "Flat-faced man of Kenya" (a name given by Meave Leakey), is the only described species in the genus. However, if some paleoanthropologists are correct, Kenyanthropus may not even represent a valid taxon, as the specimen (KNM-WT 40000) is so distorted by matrix-filled cracks that meaningful morphological characteristics are next to impossible to assess with confidence. It may simply be a specimen of Australopithecus afarensis, which is known from the same time period and geographic area, or its own species within Australopithicus, A. platyops. Other researches speculate that the flatter face position of the rough cranium is similar to KNM ER 1470 (Homo rudolfensis), and suspect it to be closer to the genus Homo, perhaps being a direct ancestor. However the debate has not been concluded and the species remains an enigma.
The bones discovered at the site included more than 30 skull and tooth fragments in a stratum dated to between 3.5 and 3.2 million years ago. Dr. Leakey believes that it belongs to an entirely new genus of ancestors, and is the oldest "reasonably complete" cranium found so far. Humans were once thought to have evolved only from Australopithecus afarensis, the species made famous by the fossil Lucy. But now it seems Lucy may have been sharing the woods and grass plains of prehistoric Africa with a rival.
When learning of the discovery, Daniel Lieberman, an anthropologist at George Washington University expressed his opinion that between 3.5 and 2 million years ago there were several human-like species, each of which were well adapted to life in their particular environments. Also that, like that of many other mammalian groups, humans evolved through a series of complex radiations, known as "adaptive radiation".
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