Homo rudolfensis (right) and Homo habilis (left)
2 million years ago marked a critical moment in human evolution as it is the first time our genus (Homo) split into more than one species; a sign our lineage was flourishing. This state of affairs would continue until 12,000 years ago; when the hobbit died and we became the last of our kind. The newcomer was Homo rudolfensis, who joined the older Homo habilis.
Both species lived in East Africa and both share many similarities with the older, more ape-like Australopithecus genus; such as long arms and short legs (a sign they may have been spending a lot of time climbing through trees). However, these early humans had one new development: a larger brain. They’d added about an extra coke cans worth of brain matter to the Australopithecus brain, a sign of the rapid development that was to come.
Although very similar in many regards, the key difference between H. habilis and H. rudolfensis (aside from the latter being younger) is that H. rudolfensis was slightly larger and had a flatter more human-like face. The evolutionary relationships between them all are still being fleshed out, so whether this is significant remains a mystery.
The new dates for the bigger, little brother of Homo habilis push its origins back from ~1.9 million years ago up to 2.058 million years ago (with a margin of error of 34,000 years). Meanwhile the latest date for the emergence of Homo rudolfensis can be refined from 1.78 million years ago to 1.945 mya. Although this may not seem like much it really helps us to get a lot more specific over just when the species evolved, which can be very useful when trying to figure out why they appeared in the first place.
References
Joordens, J. C., Dupont-Nivet, G., Feibel, C. S., Spoor, F., Sier, M. J., van der Lubbe, J. H., … & Vonhof, H. B. (2013). Improved age control on early Homo fossils from the upper Burgi Member at Koobi Fora, Kenya. Journal of Human Evolution.
