ANT2511 INTRODUCTION TO PHYSICAL ANTHROPOLOGY CHAPTER 11 EARLY HOMININS There are 3 categories of Early Hominins 1 Earliest Hominins 2 Australopithecines 3 Robust Australopithecines Bolded information important characteristic or trait 1 EARLIEST HOMININS 1 S tchadensis Toumai found in Chad Africa 320 350 cc sized brain chimplike primitive teeth Flat face brow ridge foramen magnum underneath biped 2 Orrorin tugenensis 6 mya Molars smaller than A ramidus thick enamel like us Arms fingers adapted for climbing Thigh bone more human like bipedal Mixed woodland savannah environment 3 Ardipithecus ramidus 4 5 4 3 mya Noted for enamel thickness 4 Ardipithecus kadabba 4 4 mya Found in Ethiopia 45 of skeleton found data gathered for 15 years Classified as different species because canines are more chimp like Ardipithecus is hominin because of canines and bipedalism ANT2511 INTRODUCTION TO PHYSICAL ANTHROPOLOGY Bipedal pelvis but opposable big toe Not a knuckle walker small brain A ramidus and A kadabba considered same species now classified as Ardipithecus ramidus Ardi 2 AUSTRALOPITHECINES 1 Australopithecus anamensis 4 2 3 8 mya Found in Kenya mixed woodland environment More derived characteristics large molars thick enamel small canines knees and ankles indicate bipedalism More primitive climbing arms more ape like skull receding chin Dental arcade more U shaped ape than V shaped us 2 Australopithecus afrarensis Lucy 4 3 mya 13 individuals found in multiple areas across Africa Woodland drier savannah Only in East Africa Primitive ancestral traits 404cc brain size same as chimp base is flared sub nasal prognathism non projecting canines Derived traits teeth and jaws intermediated between apes and humans between U shaped and parabolic Medium sized canines Modest diastema gap between molars canine dimorphism than chimp but than us Smaller inner cusp than chimps 1 and us 2 Primitive bipedalism less efficient ilium oriented back so abductors are less efficient shorter legs slower wider pelvis Sexual dimorphism ratio 1 5 male 1 female o Greater sexual dimorphism than humans chimps and bonobos Mixture of arboreal and terrestrial traits ANT2511 INTRODUCTION TO PHYSICAL ANTHROPOLOGY o More efficient bipedalism less efficient climbing o Sleeping in trees long arms curved fingers bipedal pelvis 3 Australopithecus Africanus Taung 3 years old 3 2 2 mya 1st Australopithecine discovered only South Africa 442 cc brain size similar to A afarensis More modern teeth than A afarensis Small brain modern dentition dentition evolved before brain size canines Location of foramen magnum indicates bipedalism Derived traits shorter face subnasal prognathism dimorphic Derived traits NOT shared with us large molars for chewing post canine megadontia Rapid maturation like chimps 4 Kenyanthropus platyops 3 5 3 2 mya Mixed woodland savannah environment Lake Turkana Africa Thick enamel but smaller molars than all but A ramidus Broad flat face Possibly distorted afarensis 5 Australopithecus garhi 2 5 mya Found in Ethiopia 450 cc brain size Very prognathic face sagittal crest Legs longer than arms unlike chimps A afarensis Canines premolars and molars larger than afarensis africanus Differed from other australopiths but lack derived features of other hominins ANT2511 INTRODUCTION TO PHYSICAL ANTHROPOLOGY 3 ROBUST AUSTRALOPITHECINES 1 Australopithecus aethiopicus 2 5 mya Black Skull Lake Turkana Kenya Jaw joint similar to A afarensis chimps gorillas whereas we have a modified jaw hinge Same brain body size as A afarensis Similar postcranially to Australopithecines with small brains relative to body size Huge molars large lower jaw for powerful chewing Flared zygomatic arch makes face look flat Huge temporalis and masseter muscles for chewing 2 Australopithecus boisei 2 2 1 3 mya Found Tanzania Robust size larger body molars for really heavy chewing 3 Australopithecus robustus 1 8 1 mya South Africa 530 cc brain size bigger brain than other australopithecines Sexual dimorphism Bipedal more heavy chewing than africanus seeds nuts meat 4 Australopithecus sediba 1 9 1 78 mya Found 2010 by Lee Berger South Africa Closest morphological comparisons are to A africanus H erectus Combo of ancestral derived traits o Cranium body size proportion austrolopith 420 cc brain size o Reduced size of molars pelvis homo trait seen in h erectus