Sterkfontein Member Research Articles

Role of carnivores in the accumulation of the Sterkfontein Member 4 hominid assemblage: a taphonomic reassessment of the complete hominid fossil sample (1936-1999).

New taphonomic data on the Sterkfontein Member 4 (South Africa) fossil hominid assemblage are presented. The previous estimate of hominid individuals represented in the deposit (45) is increased to 87. New minimum numbers of hominid skeletal elements are provided, and incidences of bone surface damage inflicted by prehistoric biological agents are summarized. The hominid sample from Member 4 is composed predominately of gnathic remains and has a paucity of postcrania. This dearth of postcrania limits, to some extent, inferences about the formation of the Sterkfontein assemblage. However, carnivore tooth marks on some fossil specimens and an overall broad similarity in patterns of skeletal part representation between Sterkfontein and primate bone assemblages created by extant carnivores suggest that carnivores did have some involvement in the accumulation of the fossil hominid assemblage. Thus, this study provides support for the "carnivore-collecting hypothesis" of Brain (Brain [1981] The Hunters or the Hunted? Chicago: University of Chicago Press), which implicates large carnivores as prominent collecting agents of hominid body parts in Sterkfontein Member 4. Evidence of bone surface damage is, however, too scant to make confident inferences about specific carnivore taxon/taxa involved in hominid bone collection at the site.

Identifying metameric variation in extant hominoid and fossil hominid mandibular molars.

Landmark data were collected from cross sections and occlusal images of mandibular molar crowns, and Euclidean distance matrix analysis (EDMA) was used to identify metameric morphological variation between the first and second mandibular molars of living taxa: Gorilla gorilla (n = 30), Pan troglodytes (n = 34), and Homo sapiens (n = 26). Two patterns of metameric variation were identified, one unique to humans and the other shared by chimpanzees and gorillas. In order to assess the utility of this type of analysis for the interpretation of the hominid fossil record, 19 mandibular molars from Sterkfontein Member 4, South Africa, were examined. The pattern of metameric variation of the Sterkfontein molars resembled that of the African great apes, and differed from the modern human pattern. These results demonstrate that data on metameric variation may provide information regarding function or developmental processes previously indiscernible from fossil material.

Craniofacial diversity in earlyHomo and the affinities of the Sterkfontein Valley

The Sterkfontein Valley specimens SK 847 (Swartkrans Member 1) and Stw 53 (Sterkfontein Member 5) provide important evidence of earlyHomo in southern Africa. However, specific identity has been disputed, with that of SK 847 especially contentious. Opinions differ markedly as to whether the specimens are conspecific or not, whether they should be referred to East African earlyHomo species, or whether they represent new species. Morphometric analysis of facial dimensions reveals contrasting affinities for the two South African fossils, and so does not support claims for their conspecifity. Stw 53 is very like smaller East African crania referred toH. habilis, whereas SK 847 has a distinctive facial pattern. In some respects it resembles early AfricanH. erectus (=H. ergaster), but with a markedly more projecting mid-face, prominent zygomatic and unexpanded frontal region, all of which militate against inclusion in that species. The taxonomic implications of these contrasting facial affinities are briefly discussed.

The Plio-Pleistocene vegetation and climate of Sterkfontein and Swartkrans, South Africa, based on micromammals

Micromammalian remains from Oldowan and Acheulean horizons in Sterkfontein Member 5E (M5E-O and M5E-A) and Swartkrans Members 1–3 (SKX1–3) provide information for the period between about 2 and 1Ma. Another small sample from Sterkfontein Member 4 (M4) refers to a short period around 2·8–2·6Ma and material from Sterkfontein post Member 6 infill (post-M6) relates to the Middle Stone Age occupation around 100ka.Virtual absence of evidence of digestion on in situ lower molars of the major prey species, Mystromys albicaudatus, indicates that one of the owls Tyto alba, T. capensis or Asio capensis was the responsible predator. Over-emphasis on riverine grassland supports this suggestion, as does faunal resemblance between the Sterkfontein Valley samples and modern prey samples for the three owl species concerned. The location of the roost and the range of prey species point to the barn owl T. alba. There is no indication of differential bias between samples. South African species of eagle owl (Bubo spp.) are ruled out.All samples appear to represent interglacial conditions. The Grassland—Savanna ecotone probably lay nearby, as did the border between Moist and Arid Savanna. Possible modern analogues occur about 200km west and southwest of the valley more than 250m lower in altitude. South of Mafikeng all three vegetation types intergrade but the rainfall is higher than that postulated for some of the units in the Sterkfontein Valley. Similar climatic conditions occur near Kuruman and Kimberley where Arid Savanna merges into Grassland. Landscape information indicates a succession from riverine grassland, sometimes withAcacia trees, through hillsides with bush, grass and some trees, to plains with open savanna woodland. The suggested climate for the Sterkfontein Valley varied between ±310mm and possibly 550mm mean annual precipitation, summer aridity index 3·8–4·1 and percentage winter rainfall 23–24. Minimum and maximum monthly temperatures would have been higher than they are today but with the temperature range reduced.

Diet, Body Size, and Landscape Use among Holocene People in the Southern Cape, South Africa

Diet, Body Size, and Landscape Use among Holocene People in the Southern Cape, South Africa

Diet, Body Size, and Landscape Use among Holocene People in the Southern Cape, South Africa

Diet, Body Size, and Landscape Use among Holocene People in the Southern Cape, South Africa

The new hominid skeleton from Sterkfontein, South Africa: age and preliminary assessment

A new hominid skeleton from Sterkfontein Member 2 attaches to foot bones recovered from loose blocks during the 1980s and first described in 1995. Several flowstone horizons are present above and below the skeleton and have given clear palaeomagnetic signatures. Five changes in magnetic polarity have been identified; when constrained by the available biostratigraphy, this sequence can be placed confidently between 3.22 and 3.58 Ma. Interpolation of sedimentation rates over the small intervals between reversals allows this range to be reduced to 3.30–3.33 Ma. The skeleton is thus the oldest yet discovered and is considered to belong to a species of Australopithecus other than africanus. Copyright © 1999 John Wiley & Sons, Ltd.

A large male hominin cranium from Sterkfontein, South Africa, and the status ofAustralopithecus africanus

Stw 505 is the most complete hominin cranium discovered in Sterkfontein Member 4 since Broom's excavations. It was foundin situin Member 4 breccia in 1989 and is larger, on the whole, than any other cranium from Sterkfontein that has comparable parts. Displacement due to breakage, as well as plastic deformation, has affected Stw 505 in several areas, especially the face and the vault. Diagnosticmorphology is nevertheless abundant in the specimen. In several areas—the distinct anterior pillar, the straight inferior border of the zygoma, the pattern of cresting on the naso-alveolar clivus, the basal aspect of the temporal bone—Stw 505 closely matches the morphology of specimens ofAustralopithecus africanusand is distinct from other hominins. Some isolated characters overlap with other groups, mainly earlyHomoand/orA. robustus. However, only the hypodigm ofA. africanuscan accommodate the entire suite of morphology.In some cases, Stw 505 introduces more variation into the Sterkfontein sample. For example, prominent superciliary eminences occupy the medial portions of the supraorbital region and flow medially into a strongly protruding glabellar mound. These characteristics are probably attributable to sexual dimorphism. In many respects, Stw 505 highlights similarities betweenA. africanusand earlyHomo. Comparison with other species suggests that males ofA. africanusdo not show derived features ofA. robustusthat are not also present in females, and that cranial differences betweenA. afarensisandA. africanushave, if anything, been understated.

Sexual dimorphism in the face of Australopithecus africanus.

Recently discovered crania of Australopithecus africanus from Sterkfontein Member 4 and Makapansgat enlarge the size range of the species and encourage a reappraisal of both the degree and pattern of sexual dimorphism. Resampling methodology (bootstrapping) is used here to establish that A. africanus has a greater craniofacial size range than chimpanzees or modern humans, a range which is best attributed to a moderately high degree of sexual dimorphism. Compared to other fossil hominins, this variation is similar to that of Homo habilis (sensu lato) but less than that of A. boisei. The finding of moderately high dimorphism is corroborated by a CV-based estimate and ratios between those specimens considered to be male and those considered to be female. Inferences about the pattern of craniofacial dimorphism in the A. africanus face currently rely on the relationship of morphology and size. Larger specimens, particularly Stw 505, show prominent superciliary eminences and glabellar regions, but in features related in part to canine size, such as the curvature of the infraorbital surface, large and small specimens of A. africanus are similar. In this respect, the pattern resembles that of modern humans more so than chimpanzees or lowland gorillas. A. africanus may also show novel patterns of sexual dimorphism when compared to extant hominines, such as in the form of the anterior pillar. However, males of the species do not exhibit characteristics of more derived hominins, such as A. robustus.

Sexual dimorphism in the face of Australopithecus africanus

Recently discovered crania of Australopithecus africanus from Sterkfontein Member 4 and Makapansgat enlarge the size range of the species and encourage a reappraisal of both the degree and pattern of sexual dimorphism. Resampling methodology (bootstrapping) is used here to establish that A. africanus has a greater craniofacial size range than chimpanzees or modern humans, a range which is best attributed to a moderately high degree of sexual dimorphism. Compared to other fossil hominins, this variation is similar to that of Homo habilis (sensu lato) but less than that of A. boisei. The finding of moderately high dimorphism is corroborated by a CV-based estimate and ratios between those specimens considered to be male and those considered to be female. Inferences about the pattern of craniofacial dimorphism in the A. africanus face currently rely on the relationship of morphology and size. Larger specimens, particularly Stw 505, show prominent superciliary eminences and glabellar regions, but in features related in part to canine size, such as the curvature of the infraorbital surface, large and small specimens of A. africanus are similar. In this respect, the pattern resembles that of modern humans more so than chimpanzees or lowland gorillas. A. africanus may also show novel patterns of sexual dimorphism when compared to extant hominines, such as in the form of the anterior pillar. However, males of the species do not exhibit characteristics of more derived hominins, such as A. robustus. Am J Phys Anthropol 108:97–127, 1999. © 1999 Wiley-Liss, Inc.

Erratum: Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

In line 25 of the technical comment “Faunal evidence and Sterkfontein Member 2 foot bones of early hominid” by Jeffrey K. McKee (1 Mar., p. 1301),” Chasmaphorthetes silberbegi” was spelled incorrectly.

Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

Response : Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

<i>Response</i> : Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

Response: Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

Response: Faunal Evidence and Sterkfontein Member 2 Foot Bones of Early Hominid

Sterkfontein Member 2 Foot Bones of the Oldest South African Hominid

Four articulating hominid foot bones have been recovered from Sterkfontein Member 2, near Johannesburg, South Africa. They have human features in the hindfoot and strikingly apelike traits in the forefoot. While the foot is manifestly adapted for bipedalism, its most remarkable characteristic is that the great toe (hallux) is appreciably medially diverged (varus) and strongly mobile, as in apes. Possibly as old as 3.5 million years, the foot provides the first evidence that bipedal hominids were in southern Africa more than 3.0 million years ago. The bones probably belonged to an early member of Australopithecus africanus or another early hominid species.

Faunal assemblage seriation of southern African Pliocene and Pleistocene fossil deposits.

Fossil assemblages from the Pliocene and Pleistocene of southern Africa were seriated in order to give a better idea of their relative chronology. Time-sensitive mammals were selected for calculation of the Faunal Resemblance Index among 17 site units. On the basis of a logistical seriation and subsequent site analysis, the following sequence of sites was deemed most probable: Makapansgat Member 3, Makapansgat Member 4, Taung Dart deposits, Sterkfontein Member 4 and Taung Hrdlicka deposits, Sterkfontein Member 5 (in part) and Kromdraai B, Kromdraai A and Swartkrans Member 1, Swartkrans Member 2, Swartkrans Member 3, Plovers Lake, Cornelia, Elandsfontein Main Site, Cave of Hearths Acheulian levels, Florisbad and Equus Cave and Klasies River Mouth.

Faunal dating of the Taung hominid fossil deposit

Abstract Although the Taung skull was once thought to be the oldest representative of Australopithecus africanus , more recent attempts to date the Taung site have ranged from 2·3 m.y.a. based on cercopithecid biochronology to as recent as 1 m.y.a. based on radiometric techniques. Recent work by Vogel has shown that the latter date can be disregarded. Our excavations of Taung deposits from 1988 to 1992, under the direction of P. V. Tobias, have revealed more fauna and geological information with which we can make a more accurate assessment of the faunal age than was possible with cercopithecids alone. On the basis of historical records and newly exposed fossil deposits deeper within the cave-riddled Thabaseek tufa, it seems likely that the Taung hominid predates the Hrdlicka deposits from which most of the fauna have been derived. Thus a faunal date derived from the combined samples can serve only as a terminus ad quem for the age of the hominid deposits. The Hrdlicka fauna falls within a time range close to that of Sterkfontein Member 4, ca. 2·4 to 2·6 m.y.a., whereas the hominid deposit could be somewhat older, in the probable range of 2·6 to 2·8 m.y.a.

Proximal femur of Australopithecus africanus from Member 4, Makapansgat, South Africa.

A left proximal femur (MLD 46) from Member 4, Makapansgat, South Africa is described and analyzed. It consists of the head, neck, and a small segment of the shaft that extends to just below the lesser trochanter. The femur exhibits degenerative joint disease in the form of marginal osteophyte formation and thus its taxonomic identity has been somewhat obscured. Consideration of all like-sized mammalian femora from Makapansgat suggests that the femur is that of either a felid or hominid. Comparison of MLD 46 to femora of extent and extinct felids reveals that MLD 46 does not possess two morphological features that are characteristic of felids, namely a deep, prolonged trochanteric fossa and a high neck-shaft angle. Simple shape variables (ratios) and multivariate analyses consistently place MLD 46 with modern and fossil hominids, and most closely align it with the australopithecines. We conclude that the femur is most reasonably attributable to Australopithecus africanus, which is the only hominid yet identified from Makapansgat. Despite its pathological condition, MLD 46 is the most complete proximal femur known for A. africanus, thereby permitting further morphological comparisons with homologues of A. afarensis and Paranthropus. Marginal osteophytes of mammalian femoral heads characteristically occur in individuals of advanced age, suggesting that MLD 46 may have lived some time with the disease. Finally, MLD 46 is considerably larger than the previously described specimen, Sts 14, from Sterkfontein Member 4. There may be as great a contrast in body size in A. africanus as there is between the large and small specimens of A. afarensis.

Evolution of the power ("squeeze") grip and its morphological correlates in hominids.

The "squeeze" form of power grip is investigated for the purposes of clarifying the hand posture and activities associated with the grip, assessing the potential in chimpanzees for using the grip, and identifying morphological correlates of an effective power grip that may be recognized in fossil hominid species. Our approaches include: (1) the analysis of the human grip, focusing on both the hand posture involved and hand movements associated with use of the grip in hammering; (2) the analysis of similar chimpanzee grips and associated movements; (3) comparative functional analysis of regions in the hand exploited and stressed by the grip and its associated movements in humans; and (4) a review of the literature on the power grip and its morphological correlates. Results of the study indicate that humans use a squeeze form of power grip effectively to wield cylindrical tools forcefully as extensions of the forearm. Several morphological features occur in high frequency among humans which facilitate the grip and are consistent with the large internal and external forces associated with it in hammering and in other tool-using activities. Chimpanzee hand postures resembling this form of human power grip are not fully comparable and lack some of these morphological correlates that facilitate its use. The hand of Australopithecus afarensis does not appear to have been stressed by use of the grip, but there is some evidence for this type of stress in the metacarpals from Sterkfontein Member 4. Hands from Olduvai and Swartkrans do not provide sufficient evidence for assessment of power grip capabilities.