Rising Star Cave, north of Johannesburg. (The cave lies within the "Cradle of Humankind" World Heritage site, which also includes the Sterkfontein, Swartkrans, and Kromdraai fossil hominid sites.)
Unknown, possibly about 2.5-2.8 mya. (In the near absence of other organic material in the cave, dating will require destruction of some specimens.)
50cm, possibly 40-50 kg.
450-550 cc. The size is similar to Australopithecus skulls, although anatomical detail (including eye socket structure) suggest brain structure more similar to Homo forms.
In general the very small skull and brain are considered similar to Australopithecus or to gracile forms of H. ergaster. Teeth are small, in common with later hominines. Small thumb and complex wrist have been suggested by the excavators to imply possible tool use, but the angle of the shoulder joints and the strongly curved fingers have been interpreted adaptations adaptation for climbing. Femurs exhibit ridges of unknown function not seen in other hominines.
Researchers stressed a foot appropriate to bipedalism, not surprising since antecedent Australopithecus forms were apparently bipedal. That said, although the feet and lower legs are similar to those in Homo, the hip bones more closely resemble those of Australopithecus. The upper body is considered more similar to late Australopithecus forms than to other early Homo forms.
The habitat cannot be estimated until the fossils can be dated and compared with a reasonable record of historical climatology. If the long fingers suggest climbing, we may probably tentatively assume a forested environment.
A very inaccessible portion of Star Cave was discovered to contain a rich scattering of hominid fossils in 2013 and remains of about 15 individuals were collected in 2013 and 2015. A preliminary report was released to the public in September, 2015, with the species name naledi ("star" in the local language). The specimens collected were those lying about on the cave floor. Additional material is embeded and will require excavation.
The excavators, noting the concentration of bodies at a relatively inaccessible cave location, suggest that this may be the first hominid form to control fire (for torches), formerly associated with H. erectus, or to engage in ritual behavior (burial), formerly associated first with H. neanderthalensis and H. sapiens. Such claims, if accepted, naturally increase the importance of this find.
A National Geographic Society documentary is available.