Middle and later Pleistocene hominins in Africaand Southwest AsiaG. Philip Rightmire1Department of Anthropology, Harvard University, Cambridge, MA 02138; and Department of Anthropology, Binghamton University (SUNY),Binghamton, NY 13902Edited by Richard G. Klein, Stanford University, Stanford, CA, and approved May 21, 2009 (received for review April 14, 2009)Approximately 700,000 years ago, Homo erectus in Africa was givingway to populations with larger brains accompanied by structuraladjustments to the vault, cranial base, and face. Such early MiddlePleistocene hominins were not anatomically modern. Their skullsdisplay strong supraorbital tori above projecting faces, flattenedfrontals, and less parietal expansion than is the case for Homosapiens. Postcranial remains seem also to have archaic features.Subsequently, some groups evolved advanced skeletal morphology,and by ca. 200,000 years ago, individuals more similar to recenthumans are present in the African record. These fossils are associatedwith Middle Stone Age lithic assemblages and, in some cases,Acheulean tools. Crania from Herto in Ethiopia carry defleshingcutmarks and superficial scoring that may be indicative of mortuarypractices. Despite these signs of behavioral innovation, neither theHerto hominins, nor others from Late Pleistocene sites such as KlasiesRiver in southern Africa and Skhu l/Qafzeh in Israel, can be matchedin living populations. Skulls are quite robust, and it is only after⬇35,000 years ago that people with more gracile, fully modernmorphology make their appearance. Not surprisingly, many ques-tions concerning this evolutionary history have been raised. Attentionhas centered on systematics of the mid-Pleistocene hominins, theirpaleobiology, and the timing of dispersals that spread H. sapiens outof Africa and across the Old World. In this report, I discuss structuralchanges characterizing the skulls from different time periods, possibleregional differences in morphology, and the bearing of this evidenceon recognizing distinct species.Homo heidelbergensis 兩 Homo sapiens 兩 human evolution 兩skull morphology 兩 systematicsStone artifacts and other traces of human activit y dating from700,000 to 130,000 years ago are found across Africa andEurasia, and a number of sites c ontain well dated archaeologicalsequences. Fossils are far less plentiful, particularly comparedwith the abundant L ate Pleistocene Neanderthals. Nevertheless,it is clear that some of the earliest populations differing fromHomo erectus are documented at localities in Africa and South-west Asia. One important example is Bodo in the Middle Awashof Ethiopia, where a cranium, a broken parietal, and a humeruswere discovered in conglomerates and sands cont aining mam-malian fossils and later Acheulean tools. Radiometric datespoint to an age of ca. 600,000 years (1). The cran ium asrec onstructed consists of the face and parts of the braincase.There are resemblances to H. erectus in the massive facialskeleton, projecting brow, low and constricted frontal withmidline keeling, and pariet al angular torus. In other respects,Bodo is advanced in its morphology. Brain size is close to 1,250cm3(2) and substantially greater than expected for H. erectus.This difference is unlikely to result simply from larger body mass(3). Frontal squama proportions, the arched temporal contour,and some traits of the cranial base are like those of more modernhumans. The browridge is divided into medial and lateralsegments, the margin of the nose is vertical rather than forwardsloping, and the incisive canal opens into the front of the palate.These are derived conditions present also in the face of recentHomo (4).Another ancient cranium and a mandibular fragment werepicked up at Elandsfontein in South Africa in 1953. Later, at the sitedesignated Cutting 10, an imal bones were uncovered withAcheulean biface s, cores, and flakes. The fauna from Cutting 10may not be associated directly with the artifacts, but the contem-poraneity of many of the Elandsfontein bones with a laterAcheulean industry is not in doubt (5). The fauna include s bovidsand other large herbivores, and there are archaic elements such asa dirk-toothed cat, a sivathere, a giant gelada baboon, and at least4 archaic hartebeest/wildebee st-like antelope species. Some 15 of 48mammalian species collected at Elandsfontein have no historicdescendants, suggesting that this assemblage is 1.0 million to⬎600,000 years old (6). The human skullcap is cracked and weath-ered, but as with Bodo, resemblance s to H. erectus are apparent. Atthe same time, the parietals are expanded (‘‘bossed’’), and theoccipital is less angulated than in H. erectus. The se differences areconsistent with an increase in brain volume.It is likely that the missing Elandsfontein facial parts aremirrored by the cranium from Broken Hill (Kabwe) in Zambia.The Broken Hill face is set forward from the anterior cranialfossa and exhibits very heav y brows. The cranial base is lessflexed than is the norm for recent people. Despite the presenceof these archaic features, the border of the nose is set vertically,and palatal anatomy is like that of later humans. Also in itsoc cipital proportions and in the temporomandibular joint re-gion, Broken Hill shares derived traits with modern populations.Unfortunately, the cave deposits containing the fossils were longago quarried away, and circumstances surrounding the 1921disc overy are no longer clear. Associations of the bones andartifacts are uncertain, but a tibia was found near the cranium.Ef forts to date the hominins are underway (7), but for themoment the best indications are mammal fossils that suggest anage comparable to Bodo or Elandsfontein (8).A Middle Pleistocene specimen from Sale´ in Morocco hasproved enigmatic, because of distortion due to pathology (9).A nother partially reconstructed braincase f rom L ake Eyasi inTanzan ia is low in profile, although the upper scale of theoc cipital is vertical. The contour of the (left) parietal is roundedwhen the skull is viewed f rom the back. More of a cranium fromL ake Ndutu is preserved. Reconstr uctive efforts (10) reveal avault that is small (1,100 cm3) with side walls that are gentlyc onvex. Also, the articular tubercle bounding the mandibularfossa is more prominent than would be the case for H. erectus,and the tympanic plate is delicate inferiorly, rather than thick-ened. The relatively gracile browridge, lack of strong
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