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Australopithecus anamensis. Named by Meave Leakey and colleagues in 1994 crania, teeth & postcrania 2 sites: Allia Bay & Kanapoi ca. 4.2-3.9 Ma. A. anamensis. LOUIS LEAKEY. Paranthropus boisei. O.H. 5 discovered 1959 “robust” australopithecine -- Zinjanthropus
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Australopithecus anamensis • Named by Meave Leakey and colleagues in 1994 • crania, teeth & postcrania • 2 sites: Allia Bay & Kanapoi • ca. 4.2-3.9 Ma
Paranthropus boisei • O.H. 5 • discovered 1959 • “robust” australopithecine -- Zinjanthropus • massive premolars and molars • tiny canines and incisors • “Human Cuisinart”
Robust australopithecines = Paranthropus • Late Pliocene - early Pleistocene deposits (2.5 -1 Ma) • East & South Africa • massive molars • flatter, braoder, “dished” faces • poorly known post-cranial anatomy • similar in size to Australopithecus
P. boisei -- female & male KNM-ER 732 KNM-ER 406
Paranthropus aethiopicus • KNM-WT 17000 • The “Black Skull” • 1985 discovery • W. Turkana (Kenya) & Omo (Ethiopia) • ca. 2.8 - 2.2 Ma • primitive “robust” australopithecine
Robustaustralopithecines Gracile australopithecines • Paranthropus robustus • P. aethiopicus • P. boisei • Australopithecus africanus • A. afarensis • A. anamensis • A. bahrelghazali Generalized jaws & teeth Specialized jaws & teeth
Australopithecus garhi • 1999 discovery by Asfaw, White and colleagues • 2.5 Ma Ethiopia’s Middle Awash region • garhi = “surprise”
A. garhi • craniodental & postcranial remains (? association) • Cranium: • small brain • prognathic face • very large teeth • Post-cranium: • long legs • long forearms • < 5 ft tall
A. garhi • Antelope remains from nearby site with cutmarks • A. garhi or another hominin species is responsible (?) • meat/marrow eating at an early date -- “hallmark” in human evolution
Encephalization Australopithecus Homo Dentition Hominin Trends
Kenyanthropus platyops nov. sp. • Disc. 1999 by Meave Leakey
Kenyanthropus platyops nov. sp. • “flat-faced man of Kenya” • 3.2 to 3.5 Ma – western • Lake Turkana • contemporary with “Lucy” • new genus -- controversial! • KNM-WT 40000 = holotype
Hominidae Australopithecinae Homininae African apes not included Australopithecines a SUBFAMILY Hominidae Gorillinae Homininae Australopithecini Hominini Australopithecines a TRIBE Confused about taxonomy?
Encephalization Australopithecus Homo Dentition Hominin Trends
Homo habilis Leakey et al., 1964 • Olduvai Gorge • Beds I and II • 2.0 - 1.6 Ma • “Handy Man” • Tool association • Passes “cerebral rubicon” • Reduced molar size
Species based on ... BED I Materials • OH 4 -- isolated teeth • OH 6 -- cranial fragments • OH 7 -- mandible, parietals, hand bones (Type) • OH 8 -- partial foot • OH 10 -- toe bone • OH 35 -- tibia & fibula • OH 48 -- clavicle • OH 49 -- radius shaft
Species based on ... BED II Materials • OH 13 -- mandible, maxilla, cranial frags (Paratype) • OH 14 -- cranial fragments • OH 16 -- partial skull
The Cerebral Rubicon Cranial Capacity (cm3) A. africanus x = 440 P. boisei x = 515 H. habilis x = 640 H. erectus x = 1000
Defining Homo habilis Craniodental Remains • retreating chin region • relatively large I & C • small (narrow) molars (relative to Australopithecus) • M3 smaller than M2 • Temporal lines never meet in midline • slight postorbital constriction
Defining Homo habilis Postcranial Remains • hand bones robust, prehensile • stout big toe, adducted • hand & forelimbs indicate climbing & weight support adaptations
OH 24 -- “Twiggy” • Olduvai Gorge -- Lower Bed I • partial & reconstructed skull • female individual • cranial capacity ca. 590 cm3 (smaller than Australopithecus) • slight postorbital constriction • domed forehead • expanded parietal region
Single Species Hypothesis • C. Loring Brace & Milford Wolpoff (University of Michigan) • 1960s & early 1970s • All anatomical differences between hominin species is Intraspecific variation, not Interspecific variation. • Only one species of hominin can exist at any one time.
Too much variation to justify single species
Wolpoff (1964) Robinson (1965) • H. habilis is indistinct from A. africanus • H. habilis diagnostic features insignificant … • Bed I = A. africanus • Bed II = early H. erectus • H. habilis direct ancestor to H. sapiens -- descended from A. africanus. H. erectus a dead end. H. sapiens Leakey (1966) H. erectus H. habilis A. africanus