AFARENSIS, EARLY HOMINID OF ABOUT 3,000,000 YEARS AGO, LIVED EAST OF THE THE RIFT VALLEY -- JUST REALIZED
New fossils from Kenya suggest that an early hominid species -- Australopithecus afarensis -- lived far eastward beyond the Great Rift Valley and much farther than previously thought. An international team of paleontologists led by Emma Mbua of Mount Kenya University and Masato Nakatsukasa of Kyoto University report findings of fossilized teeth and forearm bone from an adult male and two infant A. afarensis from an exposure eroded by the Kantis River in Ongata-Rongai, a settlement in the outskirts of Nairobi.
"So far, all other A. afarensis fossils had been identified from the center of the Rift Valley," explains Nakatsukasa. "A previous Australopithecus bahrelghazali discovery in Chad confirmed that our hominid ancestor's distribution covered central Africa, but this was the first time an Australopithecus fossil has been found east of the Rift Valley. This has important implications for what we understand about our ancestor's distribution range, namely that Australopithecus could have covered a much greater area by this age."
A. afarensis is believed to have lived 3,700,000-3,000,000 years ago, as characterized by fossils like "Lucy" from Ethiopia.
Stable isotope analysis revealed that the Kantis region was humid, but had a plain-like environment with fewer trees compared to other sites in the Great Rift Valley where A. afaransis fossils had previously appeared. "The hominid must have discovered suitable habitats in the Kenyan highlands. It seems that A. afaransis was good at adapting to varying environments," notes Nakatsukasa.