Alexeev , 1986
The species Homo rudolfensis was originally proposed in 1986 by V. P. Alexeev for the specimen KNM ER 1470. Originally thought to be a member of the species Homo habilis, much debate surrounded the fossil and its species assignment. It was thought that 2 million years ago there existed a single species in the genus Homo, and this species evolved in a linear fashion into modern humans.
But the differences in this skull, when compared to other habilines, are too pronounced, leading to the formulation of the species Homo rudolfensis, contemporary with Homo habilis.
It is not yet certain if H. rudolfensis was ancestral to the later species in Homo, or if H. habilis was, or if some third species yet to be discovered was.