Richard E. Leakey

The First Humans – Origin and Early Evolution of the Genus Homo

Part I. Retrospectives and Theoretical Perspectives 1. Early humans: of whom do we speak? Richard E. Leakey 2. Homo habilis - a premature discovery: remembered by one of its founding fathers, 42 years later Phillip V. Tobia 3. Where does the genus Homo begin, and how would we know? Bernard Wood Part II. Craniodental Perspectives on Taxonomy and Systematics 4. The origin of Homo William H. Kimbel 5. Comparisons of Early Pleistocene skulls from East Africa and the Georgian Caucasus: evidence bearing on the origin and systematics of genus Homo G. Philip Rightmire and David Lordkipanidze 6. Phenetic affinities of Plio-Pleistocene Homo fossils from South Africa: molar cusp proportions Frederick E. Grine, Heather F. Smith, Christopher P. Heesy and Emma J. Smith Part III. Postcranial Perspectives on Locomotion and Adaptation 7. Evolution of the hominin shoulder: early Homo Susan G. Larson 8. Brains, brawn, and the evolution of human endurance running capabilities Daniel E. Lieberman, Dennis M. Bramble, David A. Raichlen and John J. Shea 9. Interlimb proportions in humans and fossil hominins: variability and scaling William L. Jungers Part IV. Perspectives on Development, Diet and Behavior 10. Growth and development of the Nariokotome youth, KNM-WT 15000 M. Christopher Dean and B. Holly Smith 11. Dental evidence for diets of early Homo Peter S. Ungar and Robert S. Scott 12. Origins and adaptations of early Homo: what archaeology tells us Helene Roche, Robert J. Blumenschine and John J. Shea Part V. Environmental and Ecological Perspectives 13. Plio-Pleistocene EastAfrican pulsed climate variability and its influence on early human evolution. Mark A. Maslin and Martin H. Trauth 14. Tracking ecological change in relation to the emergence of Homo near the Plio-Pleistocene boundary. Kaye E. Reed and Samantha M. Russak 15. Ecology of Plio-Pleistocene mammals in the Omo-Turkana Basin and the emergence of Homo. Rene Bobe and Meave G. Leakey 16. Biogeochemical evidence for the environments of early Homo in South Africa Matt Sponheimer and Julia Lee-Thorp Part VI. Summary Perspective on the Workshop 17. The first humans: a summary perspective on the origin and early evolution of the genus Homo. Frederick E. Grine and John G. Fleagle

Stable isotope-based diet reconstructions of Turkana Basin hominins

Hominin fossil evidence in the Turkana Basin in Kenya from ca. 4.1 to 1.4 Ma samples two archaic early hominin genera and records some of the early evolutionary history of Paranthropus and Homo. Stable carbon isotopes in fossil tooth enamel are used to estimate the fraction of diet derived from C3 or C4 resources in these hominin taxa. The earliest hominin species in the Turkana Basin, Australopithecus anamensis, derived nearly all of its diet from C3 resources. Subsequently, by ca. 3.3 Ma, the later Kenyanthropus platyops had a very wide dietary range—from virtually a purely C3 resource-based diet to one dominated by C4 resources. By ca. 2 Ma, hominins in the Turkana Basin had split into two distinct groups: specimens attributable to the genus Homo provide evidence for a diet with a ca. 65/35 ratio of C3- to C4-based resources, whereas P. boisei had a higher fraction of C4-based diet (ca. 25/75 ratio). Homo sp. increased the fraction of C4-based resources in the diet through ca. 1.5 Ma, whereas P. boisei maintained its high dependency on C4-derived resources.

Postcranial specimens of simiolus enjiessi and other primitive catarrhines from the early miocene of lake turkana kenya

Postcranial specimens of Simiolus enjiessi and related taxa from the Lake Turkana region of Kenya are described. These specimens come from the early Miocene sites of Buluk, Kalodirr, and Moruorot. The specimens include 13 limb bones and one vertebra. Where comparisons are possible, the Simiolus material is quite similar to that of the other East African Miocene genera, Dendropithecus, Kalepithecus, Limnopithecus, and Micropithecus. These taxa share no derived features with extant hominoids and are best considered as primitive, non-cercopithecoid, non-hominoid catarrhines. The functional features of their postcrania are not closely similar to those of other Miocene catarrhines or of any extant anthropoids. The majority of postcranial features resemble those of generalized platyrrhines. These together with some specialized features, particularly of the humeroradial joint, point to the importance of arboreal quadrupedalism in the positional repertoire. The relative length of the long bones, together with specific features, especially of the humerus and femur, also indicate a suspensory capability, possibly expressed in postural activities and bridging behavior.