The History of Our Tribe Hominini Textbook Part IV Pleistocene Epoch Chapter 26 Homo naledi

26 . Homo Homo ( date unknown ) human I star in language ) Figure Skull and of gype specimen by Lee Roger Berger research team is licensed under . SITE Rising Star cave system , South Africa 157 PEOPLE Cavers Steven Tucker and Rick Hunter and investigated by Paul and Lee Berger and their associates relatively high ' relatively and Skull ard thin Skull small small medium all small volume , brain mime brain , al , toms large teeth , transverse torus small teeth , molar molar towards back res . is back Homo habilis Homo erectus Homo Homo Figure Comparison erectus and . By Chris Stringer , Natural History Museum , United Stringer , Chris ( 2015 ) The many mysteries of Homo . 4559885 . Licensed under . INTRODUCTION This newest member of our genus has once again confounded the evolutionary history of the Homo lineage . The most exciting aspect is the nature of the remains suggests that they were intentionally deposited in the deep cavern where they were discovered . was heretofore the earliest species thought to have practiced intentional body disposal . Attempts at dating the remains have not been successful . ever , 2015 ) has estimated that the species may date to , based on comparisons of date and anatomical characteristics among , and erectus ( see Figure and Chapter 27 for the erectus grade ) PHYLOGENY It appears that the majority of researchers agree that the remains reflect a new ( see references this section , especially 2015 ) Like most , the phylogeny of the species is unknown but it likely descended from an ancestry . What makes things even more difficult is that the species shares characteristics with possible extant or near extant species of Homo ( 158 The History of Our Tribe

sis , and erectus ) more derived forms ( and humans ) as well as various . The mosaic of traits is interesting and further supports the bushy nature of the tree . DISCOVERY AND GEOGRAPHIC RANGE The remains of a minimum of 15 individuals , totaling 1550 fossils ( see Figure ) were excavated in 2013 and 2014 from the Chamber , located within the Rising Star cave system in the Cradle of Humankind World Heritage Site , Province , South Africa ( Berger et al . 2015 ) The fossils are the largest collection of a species in Africa ( et al . 2015 ) The chamber is 30 below ground and is only accessible via a 12 narrow shaft ( 2015 and see Figure top right ) Based on depositional data , the bodies were deposited over time ( et al . 2015 ) Only entrance Into chamber is a 12 in vertical shaft i mining out of side CHAMBER ( Recent ( Stratigraphic position and sedimentary units ( not to sketch only ) Unit laminated maroon mudstone . Series of older restricted to the landing zone . Unit older mud . Series of younger on Cave youngest covers bones in places . mud . Recent . Figure Chamber by Paul , et al . is licensed under . PHYSICAL CHARACTERISTICS The remains are especially valuable as all body regions are represented , and some bones are articulated , so that anatomical positions and arrangements are preserved , eg . an almost complete leg of a child and an adult hand ( et al . 2015 ) The low cranial capacity , elevated shoulder joints , curved phalanges , and trunk and hip morphology are . Crania , jaw and teeth morphology , and leg bones are , for the most part , The wrist is most similar to humans and . The foot is very . Berger et al . 2015 , et al . 2015 , 2015 , 2015 ) Thus , we see an able terrestrial biped that could climb , forage , and take refuge in trees . 26 . Home 159

Figure Homo collection by Lee Roger Berger research team is licensed under . Cranial capacity falls within the range for the , with males averaging 560 and females , 465 ( Berger et al . 2015 ) The base of skull vault is flexed like members of the erectus grade and subsequent species of Homo ( see Figure and ) The vault bones are thin like those of habilis . exhibits less postorbital constriction than the earliest , yet possesses a larger supraorbital torus than any gracile ( Berger et al . 2015 ) Taken together , it is an odd combination . A more gracile face would result in less postorbital constriction , yet the supraorbital torus is associated with chewing stress . Even more surprising , the teeth are smaller than those of habilis , and the erectus grade , except for ( Berger et al . 2015 ) The skull vault is pentagonal in like Asian tus ( see Figure 265 ) due to the presence of a sagittal keel , a thickening along the midline of the skull , from front to back ( Berger et al . 2015 ) Since the trait is poorly understood in erectus , its presence in another species may shed more light on the adaptive significance or ontological processes involved . ever , unlike erectus , the keel begins in the parietal versus the frontal region ( again , see Figure 265 ) While not well developed , exhibits a canine fossa , a depression above the canine tooth , as seen in antecessor , and humans . 160 The History of Our Tribe

Figure A cast of Peking Man ( erectus ) to illustrate its sagittal keel see ridge running across the top of the skull from front to back . By . Licensed under . While the hand of ( see Figure ) shares characteristics with other , the combination of characteristics is unique . They had long fingers and the two more proximal digit phalanges are curved even more than those of , suggestive of arboreal activities . Yet their wrist morphology is most lar to and modern humans and , along with their long , robust thumb , they were thus capable of strong manipulatory activities ( Berger et al . 2015 , et al . 2015 ) Figure of by Lee Roger Berger research team is licensed under . The thorax and pelvis were flared like , but the vertebrae resemble those of the erectus grade and subsequent species of Homo . While the combination of characteristics seen in the leg bones are distinctive , they are , except that the femoral neck is long like that of . The foot ( see Figure ) is very , with 26 . Home 161

the primary differences being the curvature of their digits and less of a medial longitudinal arch ( Smith 2015 ) Figure Foot of . by Lee Roger Berger research team is licensed under . The seemingly advanced bipedal morphology of the two most recent discoveries , Au . and suggest that strong selective forces favored the ability to move through the landscape , in search of food and other resources . Berger et al . 2015 ) have calculated the weight of the sexes as follows males at 558 and females at 397 The only bone that they could use for calculating height was a tibia that yielded an estimate of 1478 . They state that the species falls within the height range of modern human populations , as well as estimates for the from ( et al . 2007 , cited in Berger et al . 2015 ) ENVIRONMENT AND WAY OF LIFE The environment of the region , at around , has already been described in the ENVIRONMENT AND WAY OF LIFE sections of Au . and . Interestingly , the site is 800 southwest of the site of . It was a neighborhood ! The evidence is compelling that the remains could not have been deposited via natural forces , but rather were carried at least part of the way , through a dark and narrow passage . We thus need to reassess our image of the cognitive capabilities and awareness of earlier members of our genus 162 The History of Our Tribe