JOHANNESBURG - A species belonging to the human family tree whose remnants were first discovered in a South African cave in 2013 lived several hundred thousand years ago, indicating that the creature was alive at the same time as the first humans in Africa, scientists said Tuesday.
A meticulous dating process showed that Homo naledi, which had a mix of human-like and more primitive characteristics such as a small brain, existed in a surprisingly recent period in paleontological terms, said Prof. Lee Berger of The University of the Witwatersrand in Johannesburg.
Berger led the team of researchers, which also announced that they had found a second cave with more fossils of the Homo naledi species, including a relatively well-preserved skull of an adult male.
The conclusion that Homo naledi was living between 236,000 and 335,000 years ago - and had not become extinct much earlier - is significant because it shows that the human species, or Homo sapiens, was evolving while another hominin species was alive, said John Hawks of the University of Wisconsin-Madison and Wits University. Previously, he said, it was thought that humans were "invincible" and had effectively replaced less-developed species in the human family tree.
The next step in research is to "sort the relationship of these different species to each other and also their role in our process of becoming human," Hawks said during an announcement of the discoveries at the Cradle of Humankind, a site near the South African town of Magaliesburg where the fossils were found. The research was also published in the journal eLife.
The name of Homo naledi refers to the "Homo" evolutionary group, which includes modern people and our closest extinct relatives, and the word for "star" in a local language. The finds have been made in the Rising Star cave system, which includes more than 2 kilometres of underground, mapped passageways. The second chamber containing the more recent fossil discoveries is about 100 metres from the cave where the original discoveries were made, and publicly announced in 2015.
The creature, which evidently walked upright, represents a mix of traits. For example, the hands and feet look like Homo, but the shoulders and the small brain recall Homo's more ape-like ancestors, according to researchers.
