The alpha taxonomy of Australopithecus at Sterkfontein: The postcranial evidence

The possibility that the fossils attributed to Australopithecus africanus represent more than a single species is of significance because of the pivotal role that A. africanus has played in discussions about hominin evolution. The A. africanus hypodigm that is currently widely recognized evinces considerable variation in a number of craniodental characters, and this has led to speculation that more than one australopith taxon may be represented among the specimens from Sterkfontein. Although crania, mandibles and teeth have dominated these taxonomic discussions, the Sterkfontein postcranial remains also have been invoked. While several workers have proposed that some of the craniodental remains from Sterkfontein can be partitioned into two groups, there is a notable lack of agreement among them as to their actual sorting. Most of the craniodental observations that have been put forward in support of arguments for taxonomic heterogeneity of the Sterkfontein australopith assemblage have been subjective and anecdotal in nature. So too, the postcranial evidence that has been cited in support of more than one australopith species at Sterkfontein has been largely subjective, and limited to a small number of elements. The results of quantitative statistical analyses of the craniodental and postcranial fossils that have been undertaken to date are not necessarily consistent with the hypothesis of taxonomic heterogeneity.     

Sex at Sterkfontein: 'Mrs. Ples' is still an adult female

The important question of whether the Australopithecus africanus hypodigm is taxonomically heterogeneous revolves largely around the interpretation of the morphological variation exhibited by the fossils from Sterkfontein. The sex assignment of these specimens is a critical component in the evaluation of their morphological variability. The Sts 5 cranium is pivotal in this regard because it is the most complete and undistorted specimen attributed to A. africanus. Although it has traditionally been regarded as an adult female, this view has been challenged. In particular, it has been argued recently that Sts 5 is a juvenile and that this, together with alveolar bone loss that has supposedly reduced the size of the canine socket, has led to its misinterpretation as a female. Virtual reconstruction of the M³ roots (and/or alveoli) contradicts arguments that these teeth were erupting at the time of death. Regardless, canine emergence and root completion are well ahead of M³ development in juvenile australopiths from Sterkfontein. Thus, even if the M³ root of Sts 5 was incomplete, its canine root would have been fully formed. Measurements of palate depth indicate that the alveolar margins of Sts 5 have not suffered from much (if any) bone loss in the region of the C/P³; any additional bone would result in a palate of truly exceptional depth. Therefore, the dimensions of the canine alveolus of Sts 5 can be regarded as proxies for those of the canine root. The canine root of Sts 5 is among the smallest recorded for any Sterkfontein australopith, which provides strong support for Robert Broom's initial attribution of sex to this specimen. There is no evidence to contradict the assertion that ‘Mrs. Ples’ is an adult female.     

Development and Essential Oil Content of Secretory Glands of Sage (Salvia officinalis)

Scanning electron microscopy of sage (Salvia officinalis L.) leaves confirmed the presence of two basic types of glandular trichomes consisting of a capitate stalked form containing a multicellular stalk and surmounted by a unicellular secretory head, and a capitate sessile form containing a unicellular stalk and unicellular, or multicellular, secretory head. In the latter type, secretory activity and filling of the subcuticular cavity may begin at virtually any stage of the division cycle affording fully developed glands containing from one to twelve cells in the secretory head. Gas liquid chromatographic analysis of the oil content of the most numerous gland species (capitate stalked, capitate sessile with one and with eight secretory cells) indicated only minor quantitative differences in essential oil composition. Thus, each gland type is capable of producing the four major monoterpene families (p-menthanes, pinanes, bornanes and thujanes) characteristic of sage.     

Glandular trichomes of <Emphasis Type="Italic">Tussilago Farfara</Emphasis> (Senecioneae,Asteraceae)

Main conclusion

The glandular trichomes are developed on the aerial organs of Tussilago farfara ; they produce phenols and terpenoids. Smooth endoplasmic reticulum and leucoplasts are the main organelles of the trichome secretory cells. The aim of this study was to characterise the morphology, anatomy, histochemistry and ultrastructure of the trichomes in Tussilago farfara as well as to identify composition of the secretory products. Structure of trichomes located on the peduncles, bracts, phyllaries, and leaves were studied by light and electron microscopy. The capitate glandular trichomes consist of a multicellular head and a biseriate long stalk. Histochemical tests and fluorescence microscopy reveal phenols and terpenoids in the head cells. During secretory stage, the head cells contain smooth and rough endoplasmic reticulum, Golgi apparatus, diversiform leucoplasts with opaque contents in lamellae, chloroplasts, mitochondria, and microbodies. In the capitate glandular trichomes of T. farfara subcuticular cavity is absent, unlike glandular trichomes in other Asteraceae species. For the first time, content of metabolites in the different vegetative and reproductive organs as well as in the isolated capitate glandular trichomes was identified by GC–MS. Forty-five compounds, including organic acids, sugars, polyols, phenolics, and terpenoids were identified. It appeared that metabolite content in the methanol extracts from peduncles, bracts and phyllaries is biochemically analogous, and similar to the metabolites from leaves, in which photosynthesis happens. At the same time, the metabolites from trichome extracts essentially differ and refer to the above-mentioned secondary substances. The study has shown that the practical value of the aerial organs of coltsfoot is provided with flavonoids produced in the capitate glandular trichomes.

     

An ecological reassessment of the southern African carnivore guild: a case study from Member 4, Sterkfontein, South Africa

The southern African late Pliocene to early Pleistocene carnivore guild was much larger than that of the present day. Understanding how this guild may have functioned is important for the reconstruction of carnivore-hominin interactions and to assess the potential for hominin scavenging in southern Africa. In modern ecosystems, the coexistence of larger carnivore species is constrained by several factors, which include high levels of interspecific competition. Here, the composition of the fossil carnivore guild is examined using Sterkfontein Member 4 (Cradle of Humankind, South Africa) as a case study. Sterkfontein Member 4 contains 10 larger carnivore taxa (body mass > 21.5 kg) and may also contain two Australopithecus species. Two possible causes of higher numbers of carnivore species in the South African fossil record are initially considered. First, that there is a bias introduced through comparing assemblages of differing sizes; second, carnivore biodiversity may have been artificially inflated due to previous taxonomic splitting of carnivore species, such as Crocuta. These possibilities are rejected and modern ecological data are used to construct a simple spatial model to determine how many carnivores could have co-existed. Although the resulting model indicates that the carnivore taxa present in Member 4 could have co-occurred, modern ecological studies indicate that it is highly unlikely that they would have co-existed simultaneously. Considering the complex depositional processes that operate in the southern African cave sites, it is proposed that the larger carnivore guild observed in the Sterkfontein Member 4 fossil assemblage is a palimpsest created by time-averaging. In light of this, we suggest that sites which have a large number of carnivore taxa should be examined for time-averaging, while those sites which have relatively few species may be a better reflection of carnivore communities.     

Nectar and oleiferous trichomes as floral attractants in <Emphasis Type="Italic">Bulbophyllum saltatorium</Emphasis> Lindl. (Orchidaceae)

Although many Orchidaceae have deceit flowers that produce no reward, the most common reward, when present, is nectar. Bulbophyllum, however, is unusual in that the labellar secretions of most species investigated to date lack sugars, and, therefore, cannot be considered true nectar. The African species Bulbophyllum saltatorium is an exception in that it produces not only nectar but also possesses specialized, capitate oleiferous trichomes. The nectary of B. saltatorium is borne on the labellum and is represented by a deep, narrow, median longitudinal groove, having a small aperture, and flanked by trichomes. Isodiametric epidermal cells lining this groove secrete nectar which collects both in the groove and on the surface of the labellum. As well as a nectary, the labellum of B. saltatorium also bears three types of unicellular trichomes: the longest trichomes are borne distally and abaxially; the marginal ones form a rim around the entire labellum, and finally, massive, capitate trichomes occur proximally and adaxially. These are oleiferous, containing large quantities of oil which might function as precursors of volatile components of fragrance or provide a food-reward. To the best of our knowledge, this is the first time for such oleiferous trichomes to be described for Bulbophyllum. Therefore, apart from their color and markings, flowers of this species are able to attract pollinators in at least two, possibly three ways: food-reward in the form of nectar; fragrance; and possibly food-rewards in the form of food-hairs.     

Molar microwear and dietary reconstructions of fossil cercopithecoidea from the Plio-Pleistocene deposits of South Africa

The South African Plio-Pleistocene cave deposits have yielded a diverse cercopithecoid fauna. In this study, the possible dietary proclivities of these extinct species are examined using details of molar microwear. Although sample sizes are often small, wear patterns suggest possible temporal changes in the diets of Parapapio jonesi from Makapansgat to Sterkfontein, of Papio robinsoni from Sterkfontein to Swartkrans, and Cercopithecoides williamsi from Makapansgat to Sterkfontein to Swartkrans. However, there does not appear to have been a significant change in the dietary habits of Parapapio broomi over time. The microwear patterns of the two temporally successive congeners, Theropithecus darti and T. oswaldi show no significant differences from one another. The sympatric congeners, Parapapio broomi and Pp. jonesi, have microwear signatures that differ significantly at Makapansgat (Members 3 and 4) but not at Sterkfontein (Member 4). Finally, the microwear analyses suggest that the extinct cercopithecoid species did not necessarily have diets similar to those of their closest living relatives.     

Examining affinities of the Taung child by developmental simulation

As a well-preserved juvenile and the type specimen of Australopithecus africanus, the Taung child figures prominently in taxonomic, ontogenetic, and phylogenetic analyses of fossil hominins. Despite general agreement about allocation of Sterkfontein and Makapansgat fossils to this species, limited morphological comparisons have been possible between these adult specimens and the juvenile Taung. Here, we used developmental simulation to estimate the adult form of the Taung child, and directly compare its morphology to that of other fossil hominins. Specimens were represented by 50 three-dimensional landmarks superimposed by generalized Procrustes analysis. The simulation process applied developmental trajectories from extant hominine species to the Taung fossil in order to generate its adult form. Despite differences found in the developmental patterns of these modern species, simulations tested on extant juveniles-transforming them into "adults" using trajectories from other species-revealed that these differences have negligible impact on adult morphology. This indicates that morphology already present by occlusion of the first permanent molar is the primary determinant of adult form, thereby supporting use of extant trajectories to estimate the morphology of an extinct species. The simulated Taung adult was then compared to other adult fossils. As these comparisons required assumptions about the pattern and magnitude of developmental change, additional analyses were performed to evaluate these two parameters separately. Results of all analyses overwhelmingly rejected the possibility that the Taung child was a juvenile robust australopith, but were consistent with the hypothesis that the Taung and Sterkfontein fossils are conspecific. Between Sts 5 and Sts 71, the latter is more likely to resemble the adult form of the Taung child.     

The view from the Lincoln Cave: mid- to late Pleistocene fossil deposits from Sterkfontein hominid site, South Africa

The Lincoln-Fault cave system lies adjacent to the Sterkfontein Cave system in the Cradle of Humankind World Heritage Site, Gauteng Province, South Africa. Lincoln Cave contains a mid- to late Pleistocene fossiliferous deposit which has been dated using uranium series methods to between 252,600+/-35,600 and 115,300+/-7,700 years old. Although speleologists presumed that there was no connection between the Lincoln Cave and Sterkfontein Cave systems, results of excavations conducted in 1997 suggest a link between the deposits. Detailed comparisons of artifacts, fauna, hominid material, and a statistical correspondence analysis (CA) of the macromammalian fauna in the deposits strongly support this hypothesis. The recovery of Early Acheulean-type artifacts from the Lincoln Cave suggests that older artifacts eroded out of Sterkfontein Member 5 West and were redeposited into the younger Lincoln Cave deposits. The close physical proximity of these deposits, and the nature of the material recovered from them, indicates that the material was probably redeposited via a link between the two cave systems. Although faunal mixing is present, it is possible to say that large carnivorans become more scarce at Sterkfontein during the mid- to late Pleistocene, while small canids and felids appear to become more abundant, indicating that large and small carnivorans probably varied their use of the site through time. This may also reflect an increasing presence of humans in the Sterkfontein area during the mid- to late Pleistocene.     

Revised age estimates of Australopithecus-bearing deposits at Sterkfontein,South Africa

The Sterkfontein fossil site in South Africa has produced the largest concentration of early hominin fossils from a single locality. Recent reports suggest that Australopithecus from this site is found within a broad paleontological age of between 2.5-3.5 Ma (Partridge [2000] The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 100-125; Partridge et al. [2000a], The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 129-130; Kuman and Clarke [2000] J Hum Evol 38:827-847). Specifically, the hominin fossil commonly referred to as the "Little Foot" skeleton from Member 2, which is arguably the most complete early hominin skeleton yet discovered, has been magnetostratigraphically dated to 3.30-3.33 Ma (Partridge [2000] The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 100-125; Partridge et al. [2000a], The Cenozoic of Southern Africa, Oxford: Oxford Monographs, p. 129-130). More recent claims suggest that hominin fossils from the Jacovec Cavern are even older, being dated to approximately 3.5 Ma. Our interpretation of the fauna, the archeometric results, and the magnetostratigraphy of Sterkfontein indicate that it is unlikely that any Members yet described from Sterkfontein are in excess of 3.04 Ma in age. We estimate that Member 2, including the Little Foot skeleton, is younger than 3.0 Ma, and that Member 4, previously dated to between 2.4-2.8 Ma, is more likely to fall between 1.5-2.5 Ma. Our results suggest that Australopithecus africanus should not be considered as a temporal contemporary of Australopithecus afarensis, Australopithecus bahrelghazali, and Kenyanthropus platyops.     

Foliar secretory trichomes of Ocimum obovatum (Lamiaceae): micromorphological structure and histochemistry

This study characterises the micromorphology, ultrastructure and main chemical constituents of the foliar glandular trichomes of Ocimum obovatum using light and electron microscopy and a variety of histochemical tests. Two types of glandular trichomes occur on the leaves: large peltate and small capitate. The head of each peltate trichome is made up of four broad head cells in one layer. The head of each capitate trichome is composed of two broad head cells in one layer (type I) or a single oval head cell (type II, rare). In peltate heads, secretory materials are gradually transported to the subcuticular space via fracture in the four sutures at the connecting walls of the head cells. Release to the head periphery occurs through opposite fracture in the four sutures in the head cuticle. In type I capitate trichomes, release of the secretions to the subcuticular space occurs via a pore between the two head cells, and release to the head periphery occurs through the opposite pore in the head cuticle. In type II capitate trichomes, the secreted material is released from the head cell through a ruptured particular squared area at the central part of the head cuticle. These secretion modes are reported for the first time in the family Lamiaceae. Histochemical tests showed that the secretory materials in the glandular trichomes are mainly essential oils, lipophilic substances and polysaccharides. Large peltate trichomes contain a large quantity of these substances than the small capitate trichomes. Ultrastructural evidence suggests that the plastids produce numerous lipid droplets, and the numerous polysaccharide small vesicles are derived from Golgi bodies.     

Possible Brucellosis in an Early Hominin Skeleton from Sterkfontein,South Africa

We report on the paleopathological analysis of the partial skeleton of the late Pliocene hominin species Australopithecus africanus Stw 431 from Sterkfontein, South Africa. A previous study noted the presence of lesions on vertebral bodies diagnosed as spondylosis deformans due to trauma. Instead, we suggest that these lesions are pathological changes due to the initial phases of an infectious disease, brucellosis. The macroscopic, microscopic and radiological appearance of the lytic lesions of the lumbar vertebrae is consistent with brucellosis. The hypothesis of brucellosis (most often associated with the consumption of animal proteins) in a 2.4 to 2.8 million year old hominid has a host of important implications for human evolution. The consumption of meat has been regarded an important factor in supporting, directing or altering human evolution. Perhaps the earliest (up to 2.5 million years ago) paleontological evidence for meat eating consists of cut marks on animal remains and stone tools that could have made these marks. Now with the hypothesis of brucellosis in A. africanus, we may have evidence of occasional meat eating directly linked to a fossil hominin.     

Echoes from the past: New insights into the early hominin cochlea from a phylo-morphometric approach

We investigate cochlear variation, an indirect evidence of auditory capacities among early hominins and extant catarrhine species, in order to assess (i) the phylogenetic signal of relative external cochlear length (RECL) and oval window area (OWA), (ii) the evolutionary model with the highest probability of explaining our observed data, (iii) some hominin ancestral nodes for RECL and OWA. RECL has a high phylogenetic signal under a Brownian motion model, and is closely correlated with body mass. Our model-based method has the advantage over parsimony-based methods of incorporating branch lengths in a phylo-morphospace, and this shows RECL shifted towards significantly higher values at the Homo erectus-Homo sapiens node. We also observe that the StW 53 and KB 6067 fossil specimens from Sterkfontein and Kromdraai likely represent one or two distinct, smaller-bodied and less derived hominin form(s) compared to Paranthropus specimens represented at Swartkrans.     

Molecular phylogenetic evidence supports a new family of octocorals and a new genus of Alcyoniidae (Octocorallia,Alcyonacea)

Molecular phylogenetic evidence indicates that the octocoral family Alcyoniidae is highly polyphyletic, with genera distributed across Octocorallia in more than 10 separate clades. Most alcyoniid taxa belong to the large and poorly resolved Holaxonia–Alcyoniina clade of octocorals, but members of at least four genera of Alcyoniidae fall outside of that group. As a first step towards revision of the family, we describe a new genus, Parasphaerasclera gen. n., and family, Parasphaerascleridae fam. n., of Alcyonacea to accommodate species of Eleutherobia Pütter, 1900 and Alcyonium Linnaeus, 1758 that have digitiform to digitate or lobate growth forms, completely lack sclerites in the polyps, and have radiates or spheroidal sclerites in the colony surface and interior. Parasphaerascleridae fam. n. constitutes a well-supported clade that is phylogenetically distinct from all other octocoral taxa. We also describe a new genus of Alcyoniidae, Sphaerasclera gen. n., for a species of Eleutherobia with a unique capitate growth form. Sphaerasclera gen. n. is a member of the Anthomastus–Corallium clade of octocorals, but is morphologically and genetically distinct from Anthomastus Verrill, 1878 and Paraminabea Williams & Alderslade, 1999, two similar but dimorphic genera of Alcyoniidae that are its sister taxa. In addition, we have re-assigned two species of Eleutherobia that have clavate to capitate growth forms, polyp sclerites arranged to form a collaret and points, and spindles in the colony interior to Alcyonium, a move that is supported by both morphological and molecular phylogenetic evidence.     

The Australopithecus assemblage from Sterkfontein Member 4 (South Africa) and the concept of variation in palaeontology

Interpreting morphological variation within the early hominin fossil record is particularly challenging. Apart from the fact that there is no absolute threshold for defining species boundaries in palaeontology, the degree of variation related to sexual dimorphism, temporal depth, geographic variation or ontogeny is difficult to appreciate in a fossil taxon mainly represented by fragmentary specimens, and such variation could easily be conflated with taxonomic diversity. One of the most emblematic examples in paleoanthropology is the Australopithecus assemblage from the Sterkfontein Caves in South Africa. Whereas some studies support the presence of multiple Australopithecus species at Sterkfontein, others explore alternative hypotheses to explain the morphological variation within the hominin assemblage. In this review, I briefly summarize the ongoing debates surrounding the interpretation of morphological variation at Sterkfontein Member 4 before exploring two promising avenues that would deserve specific attention in the future, that is, temporal depth and nonhuman primate diversity.     

Palaeomagnetic analysis of the Sterkfontein palaeocave deposits: implications for the age of the hominin fossils and stone tool industries

Palaeomagnetic analysis was conducted on speleothems from Members 1-5 at Sterkfontein Cave, South Africa. Palaeomagnetic analysis of siltstone and speleothem from the bulk of Member 4 indicate a reversed magnetic polarity that dates the deposits and its Australopithecus africanus fossils to between 2.58 and ∼2.16 Ma. Further confirmation of this age comes in the form of two short normal polarity events correlated to the Rèunion (∼2.16 Ma) and Huckleberry Ridge (∼2.05 Ma) events in speleothem capping the bulk of Member 4 and coeval with deposition of the final phase of Member 4, including A. africanus fossil Sts 5. At ∼2.16-2.05 Ma, Sts 5 is the youngest representative of A. africanus yet discovered. Palaeomagnetic analysis of the Silberberg Grotto deposits identifies a single short geomagnetic field event in flowstone overlying the StW 573 Australopithecus fossil, which is suggested to represent the Rèunion event at ∼2.16 Ma. This further supports the uranium lead age estimates of 2.3-2.2 Ma for the StW 573 fossil. Based on a reversed polarity for the deposits below the skeleton it cannot be older than 2.58 Ma. If StW 573 is considered to be a second species of Australopithecus then this indicates that two species of Australopithecus are present at Sterkfontein between 2.6 and 2.0 Ma. All of the Member 5 deposits date to less than 1.8 Ma based on a comparison of palaeomagnetic, faunal, and electron spin resonance age estimates. The StW 53 fossil bearing infill (M5A) is intermediate in age between Member 4 and the rest of Member 5 (B-C) at around 1.78-1.49 Ma. The rest of Member 5 (B-C) containing Oldowan and Acheulian stone tools and Homo and Paranthropus fossils was deposited gradually between 1.40 and 1.07 Ma, much younger than previously suggested.     

Carnivora from the Plio-Pleistocene hominin site of Drimolen, Gauteng, South Africa

Drimolen is one of the newest and most productive hominin sites in South Africa, and is dated on faunal grounds between 2.0 Ma to 1.5 Ma. This paper provides the first overview of the Carnivora from Drimolen, updating the previously published preliminary faunal list, and describing all currently prepared craniodental and postcranial material. The Drimolen specimens are described in comparison with other modern and fossil South African carnivore material. The carnivores cover a range of taxa including hyaenids, felids, canids and herpestids. Most notable amongst these are the sabretooth Dinofelis aff. piveteaui craniodental and postcranial remains, which are described in detail, and a Chasmaporthetes nitidula cranium. The genus Chasmaporthetes is found at three other sites in the area - Sterkfontein, Swartkrans and Coopers D. There are two models for the geographic origin of Dinofelis piveteaui, in that it may have arisen in either eastern or southern Africa. These possibilities are discussed in the light of the new South African Dinofelis material, as the Drimolen material appears to represent a more primitive form with affinities with D. piveteaui. Fossil leopard material from Kromdraai B and Drimolen is also discussed, as the metapodia assigned to P. pardus from these two sites are very small, but lie within the variation of modern leopards. Such size differences in fossil postcrania may have implications for the niches that these animals may have occupied in the past.     

In vivo kinematic behavior of the radio-capitate joint during wrist flexion-extension and radio-ulnar deviation.

The capitate is often considered the "keystone" of the carpus, not simply because of its central and prominent position in the wrist, but also because of its mechanical interactions with neighboring bones. The purpose of this study was to determine in vivo three-dimensional capitate kinematics. Twenty uninjured wrists were investigated using a recently developed, non-invasive markerless bone registration (MBR) technique. Surface contours of the capitate, third metacarpal and radius were extracted from computed tomography images of seven wrist positions and the three-dimensional motions of the capitate and third metacarpal were calculated with respect to the radius in wrist flexion-extension and radio-ulnar deviation. We found that in vivo capitate motion does not simply occur about a single pivot point like a universal joint, as demonstrated by non-intersecting rotation axes for different capitate motions. The distance between flexion and ulnar deviation axes was 3.9+/-2.0 mm, and the distance between extension and ulnar deviation axes was 3.9+/-1.4 mm. Furthermore, capitate axes for males tended to be located more distally than axes for females. However, we believe that this result is related to subject size and not to gender. We also found that there is minimal relative motion between the capitate and third metacarpal during these in vivo wrist motions. These findings demonstrate the complexity of capitate kinematics, as well as the different mechanisms through which wrist flexion, extension, radial deviation and ulnar deviation occur.     

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.