ANTH 3512 Lecture Notes - Lecture 5: External Occipital Protuberance, Sagittal Crest, Foramen Magnum
Document Summary
Lca of chimps and humans: expectations and influences on understanding hominin evolution. Human/chimp lineage splits about 7 million years ago- based on molecular clock data- actually might be ~12 mya: interpretations hindered by: Widest near base- nuchal rounded occipital with small crest external occipital protuberance. Normal or no suborbital torus, no sulcus, rounded. No diastema- reduction in canine size, not sexually. No canine fossa, u shape dental arcade, no chin, thin chin, thick enamel. Short toes, robust metatarsals with the developed of longitudinal medial arches. Morphotype of the lca: african ape model (aa)- more accepted 25 years. Anatomical similarities between pan and gorilla are homologues. Lca was a knuckle walker with suspensory adaptation. Chimp behavioral repertoire represents plausible capabilities of lca: ape convergence model (ac) Similarities between great apes are a result of parallel evolution (homoplasy) Shoulder morphospace analysis shows the shortest evolutionary vector is.
