Lecture 9 Genus Homo and the Australopithecines The later Robust Australopithecines General characteristics later than gracile forms specialized for chewing body slightly larger Australopithecus robustus Where found; regions and principle sites Kromdraai & Swartkrans, S. Africa; 1938; Robert Broom Distinguishing characteristics Heavy jaws, large molars, small incisors & canines Large cheekbones (zygomatics) Sagittal crest Reduced prognathism Time ranges 2.2-1.5 MYA Cranial capacity 520 cc Diet, habitat, & tool use Rough foods (nuts, stems, grasses?), mixed forest & savanna, tools? A. aethiopicus (the Black Skull) Where found; regions and principle sites Lake Turkana, Kenya; 1985; Richard Leakey Distinguishing characteristics Fairly prognathic, but with large molars & small front teeth Huge sagittal crest dished-in face Time ranges 2.6 MYA Cranial capacity 410 cc Diet, habitat, & tool use tough foods, habitat unclear, no tools A. boisei Where found; regions and principle sites Olduvai, Tanzania; 1959; Louis Leakey Lake Turkana, Kenya; 1969-76; Richard Leakey Distinguishing characteristics Largest molars of any hominid Large sagittal crest & zygomatics Less prognathism Less sexual dimorphism? Time ranges 2.2-1 MYA Cranial capacity 500-530 cc, avg 515 Diet, habitat, & tool use Rough foods, mixed forest & savanna, tools? The first member of our genus, Homo habilis. (Handy Man) Where found; regions and principle sites Olduvai, 1961, Louis Leakey Lake Turkana, early 70’s, Richard Leakey Sterkfontein S. Africa, late 70’s Distinguishing characteristics Lessened prognathism Small body w/ long arms First major brain expansion First evidence for stone tools Time ranges 2.2-1.6 Cranial capacity 500-800cc, avg. 680 Diet, habitat, & tool use Omnivorous including meat, savanna w/ wooded patches, Olduwan tools Some researchers divide into two species, H. habilis for the smaller specimens and H. rudolphensis for the larger. Habiline lifestyles Tool use- flaked stone tools How do you know it’s a tool in the first place? Find it in a strange place Amount of artifacts present More than one flake removed from a single spot on a stone Flakes and flake scars show characteristics of hard hammer percussion Striking platform Bulb of percussion Concentric rings Associated with animal bones Bones show cutmarks Cutmarks V-shaped, toothmarks U-shaped All finds of Homo habilis associated w/ stone tools Also associated w/ cutmarked and broken bone Flakes show micropolish indicating meat use Meat eating Hunting vs. scavenging Bones often show carnivore toothmarks overlapping cutmarks Cutmarks often on shaft rather than ends- getting meat quickly rather than dismembering Going for marrow in shafts of long bones Fracture patterns on bones Marrow is fat-rich, high-energy food source At 3 feet tall, hard to imagine habilis as much of a hunter Scavanging most likely Effects on body Brain very expensive to maintain- meat high energy food Easier to chew- teeth don’t need to be as big Home bases? Monogamy? Language? All three seem to be later innovations; at least clear signs of them. Characteristics of the Olduwan Oldest at 2.5 MYA- Gona, Ethiopia; named for Oduvai Gorge where first described by Louis Leakey Youngest sites ~800 KYA; Similar industries after then called by different names Generally reserved for sites in Africa; similar industries elsewhere again given other names Core tools- Choppers River cobble with one or more flakes removed near each other Can be unifacial (removed from one side) or bifacial (two sides) Used to be though of as tools in their own right, now considered to be just cores for flake tools Flake tools Sharp-edged flakes removed from a core Very useful for cutting, especially meat Sometimes shows microscopic usewear characteristic of meat cutting Hammerstones Hand-sized durable stone, like granite or quartzite Often shows pitted area where blows have been struck Quartzite ones become “polyhedral” then rounded- mistaken for bola stones