What do we mean by “hominin”?More closely related to us (Homo sapiens) than chimpanzees (P. troglodytes)Groups of early homininsBasal hominins (7-4 mya)Found at the base of hominin lineage, the earliest, furthest back in timeSahelanthropus tchadensisFound in chadLook at words for cluesOldest oneFound in upper Miocene of Chad, Central AfricaIncredible completeness for how old it isEarliest possible hominin: 7 myaIdentified by the spinal holeNot fully convinced that it’s a hominin, still some debateAn interesting mix of traitsHominoid-like, ancestral featureschimp-sized brain (about the size of an orange)Hominin-like, derived featuresForamen magnum (spinal hole)Smaller canines, with apical wearWear on teeth may hold information about social behaviorSome argue that tchadensis was a biped, other researchers are not convincedHabitat = wet, closed woodlandsOrrorin tugenensisTugen hill areaFound in highlands of Kenya in 2001~ 6 mya (K-Ar & paleomag. Dating)habitat = closed woodland & savanna (mix of grasslands and forests)ancestral featuressmall body sizearms and (long, curved) finger bones seem adapted for climbingderived featuresthick tooth enamellong femoral neck like bipedal homininsargued that this was a biped, also that aspects of the femur looked more like our genus than other fossil findingswas Orrorin a biped?Distribution of cortical bone in femoral neck supports bipedalismRevealed by femurYesDoes Orrorin look more like homo than other early hominins?Looking at all aspects of the femurA: Analysis of proximal femur shape distinguishes modern humans, great apes, and early homininsB: Cluster analysis reveals three distinct clusters: a great ape cluster, a cluster of modern and fossil Homo, and a cluster of early hominins (including Orrorin)NOArdipithecus ramidus4.4 myaEthiopiapaleoenvironment = forest2009 “Breakthrough of the year” in Sciencefossils very fragile, bad preservationstudy took 17 years due to preservation issues“Ardi”in upper limbs, does not show either evidence for knuckle walking or hanging off of limbs, maybe walk on top of limbssplayed big toe unlike any monkey or humanancestral featuresprognathic (sloping) facethin tooth enamelbigger canines than in later homininssmall brain, ape-like skullshared derived features with humansBipedal (foramen magnum, toe bones, pelvis)Upper canines not sharpened by lower premolarPelvis is relatively short and broadAustralopiths (4.2-2 mya)Australopithecus:4 species:Au. Anamensis (East Africa)4.2-3.9myainhabited dry woodlands, gallery forests and scattered grasslandsknown from over 80 specimens in 2 localitiesancestral features:u-shaped dental arcade, parallel tooth rowslarger canines than in more recent homininssharply receding chinshared derived features with humansthick tooth enamelthickness of tibia at knee and ankle joints suggest bipedalismAu. Afarensis (East Africa)“Lucy”found in Tanzania and Ethiopia3.6-3 myafully bipedal, but a relatively small brainonly about 3.5-4 ft. talllong arms, curved fingers indicate time still spent in treessexually dimorphic body size (similar to gorillas a bit)pointed canine, parallel tooth rowsearly specimens are from Laetoli, Tanzania are date to about 3.5myaLaetoli footprints2-3 creatures walked through wet volcanic ash, 3.5 myafootprints solidified as the ash driedone individual was about 4’9” and the other 4’1”footprints are similar to those made by modern people who usually walk barefootthe 3 mya knee from Hadarthe bipedal kneeDon JohansonKnown for discovering Lucy (3.2mya)Many more remains of Au. Afarensis have been found in: the “first family”Morphological characteristicsLonger and more curved phalangesDentition is intermediate between chimp-like and human-like patternAu. Africanus (South Africa)2.8-2.5 myadiscovered in 1924 by R. Dart in S. Africamorphological highlights:somewhat larger brain than Au. AfarensisSomewhat reduced canine sizeShorter arms, straighter fingers than Au. AfarensisShows adaptations to strong chewing, tough dietTaung ChildAu. Sediba (South Africa)ParanthropusP. aethiopicus“The Black Skull” because of the black fossils2.5 myaFound in Kenya by Alan Walker in 1985May be a descendent of Au. afarensisP. boisei1.8myafound in 1959 by Mary Leakey at Olduvai Gorge, TanzaniaPossibly descended from P. aethiopicus“Zinj”huge teethhuge molars are derived traits that are not shared by humansP. robustus1.8-1myaSouth AfricaRobustus = bigShows same set of adaptations as P. boiseiLikely due to convergent evolution rather than common descent What do we mean by “hominin”?- More closely related to us (Homo sapiens) than chimpanzees (P. troglodytes)- Groups of early homininso Basal hominins (7-4 mya) Found at the base of hominin lineage, the earliest, furthest back in timeSahelanthropus tchadensis Found in chad Look at words for clues Oldest one Found in upper Miocene of Chad, Central Africa Incredible completeness for how old it is Earliest possible hominin: 7 mya Identified by the spinal hole  Not fully convinced that it’s a hominin, still some debate An interesting mix of traits- Hominoid-like, ancestral features o chimp-sized brain (about the size of an orange)- Hominin-like, derived featureso Foramen magnum (spinal hole) o Smaller canines, with apical wearo Wear on teeth may hold information about social behavior Some argue that tchadensis was a biped, other researchers are not convinced Habitat = wet, closed woodlandsOrrorin tugenensis Tugen hill area Found in highlands of Kenya in 2001 ~ 6 mya (K-Ar & paleomag. Dating) habitat = closed woodland & savanna (mix of grasslands and forests)  ancestral features- small body size- arms and (long, curved) finger bones seem adapted for climbing derived features- thick tooth enamel- long femoral neck like bipedal hominins- argued that this was a biped, also that aspects of the femur looked more like our genus than other fossil findings- was Orrorin a biped?o Distribution of cortical bone in femoralneck supports bipedalismo Revealed by femuro Yes- Does Orrorin look more like homo than otherearly hominins?o Looking at all aspects of the femuro A: Analysis of proximal femur shape distinguishes modern humans, great apes, and early homininso B: Cluster analysis reveals three distinct clusters: a great ape cluster, acluster of modern and fossil Homo, and a cluster of early hominins (including Orrorin)o NOArdipithecus ramidus4.4 mya