title: First occurrence of early Homo in the Nachukui Formation (West Turkana, Kenya) at 2.3-2.4 Myr.
abstract: Cognitive abilities and techno-economic behaviours of hominids in the time period between 2.6-2.3 Myr have become increasingly well-documented. This time period corresponds to the oldest evidence for stone tools at Gona (Kada Gona, West Gona, EG 10-12, OGS 6-7), Hadar (AL 666), lower Omo valley (Ftji1, 2 & 5, Omo 57, Omo 123) in Ethiopia, and West Turkana (Lokalalei sites -LA1 & LA2C-) in Kenya. In 2002 a new palaeoanthropological site (LA1alpha), 100 meters south of the LA1 archaeological site, produced a first right lower molar of a juvenile hominid (KNM-WT 42718). The relative small size of the crown, its marked MD elongation and BL reduction, the relative position of the cusps, the lack of a C6 and the mild expression of a protostylid, reinforced by metrical analyses, demonstrate the distinctiveness of this tooth compared with Australopithecus afarensis, A. anamensis, A. africanus and Paranthropus boisei, and its similarity to early Homo. The LA1alpha site lies 2.2 m above the Ekalalei Tuff which is slightly younger than Tuff F dated to 2.34+/-0.04 Myr. This juvenile specimen represents the oldest occurrence of the genus Homo in West Turkana.
authors.affiliation: CNRS, UPR 2147, 44 rue de l'Amiral Mouchez, 75014 Paris, France. sandrineprat@ivry.cnrs.fr
authors.forename: Sandrine
authors.initials: S
authors.lastname: Prat
authors.forename: Jean-Philip
authors.initials: JP
authors.lastname: Brugal
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Tiercelin
authors.forename: Jean-Alix
authors.initials: JA
authors.lastname: Barrat
authors.forename: Marcel
authors.initials: M
authors.lastname: Bohn
authors.forename: Anne
authors.initials: A
authors.lastname: Delagnes
authors.forename: Sonia
authors.initials: S
authors.lastname: Harmand
authors.forename: Kamoya
authors.initials: K
authors.lastname: Kimeu
authors.forename: Mzalendo
authors.initials: M
authors.lastname: Kibunjia
authors.forename: Pierre-Jean
authors.initials: PJ
authors.lastname: Texier
authors.forename: Hélène
authors.initials: H
authors.lastname: Roche
mesh_terms: D000818:Animals; D015186:Hominidae / Q000033:anatomy & histology*; D006801:Humans; D007630:Kenya; D008963:Molar / Q000033:anatomy & histology*; D010161:Paleodontology