A new morphometric analysis of the hominid pelvic bone

This study is based upon a new morphometric technique providing both size and shape variables. It has been applied to 189 pelvic bones of extant humans and African apes as well as to 13 hominid pelvic bones of various taxonomic status. The main aim of this work is to include such fossil bones in the same study in order to set a synthetic comparison of their shape in the light of the yardstick given by the African ape/human pelvic bone comparison. To do so, ratio diagrams are chosen because they are simple and very expressive tools with which to present such comparisons. Shape differences are very well illustrated and quantified by this technique. The ilium appears to be the most different of the three parts of the pelvic bone. Compared to these differences, discrepancies between fossil hominid and extant human bones are of a totally different scale. This shows the architectural unity related to the acquisition of bipedalism by hominids. It is nonetheless possible to detect two levels of difference. The first separates Australopithecus from Homo and could be seen as reflecting locomotor differences between both genera. The second splits both Homo erectus and Neanderthal from modern human pelvic bones. It appears from the hominid fossil record of pelvic bones that two periods of stasis exist and are separated by a period of very rapid evolution corresponding to the emergence of the genus Homo. We are of the opinion that the same could be true for the split between African ape and hominid lineages at the end of the Miocene.     

New evidence of the genus Homo from East Rudolf,Kenya (III)

A new fossil hominid partial skeleton (KNM-ER 803) that was discovered from the Plio-Pleistocene sediments to the east of Lake Rudolf is described. It includes parts of a femur, two tibiae, an ulna, two radii, a third metatarsal and several toe bones. There are also two teeth, an upper canine and an upper central incisor. A second new fossil hominid (KNM-ER 164) is represented by a parietal fragment, two vertebrae and some hand bones. A third is represented by a massive left femur (KNM-ER 999). The specimens are described in anatomical detail, some are illustrated and selected measurements are given. It is concluded that they should be attributed to the genus Homo sp. indet. Detailed comparative studies will be published in due course.     

Quantitative genetic variation in the skeleton of the mouse: II. Description of variation within and between inbred strains

Variation in the skeletons of over 400 male and female mice from 12 genotypes was investigated by using multivariate statistical methods. A series of discriminant functions explains the differences in the shape of six bones: mandible, os coxae, femur, tibia-fibula, scapula, and humerus. The anatomical features of bone shape described by these functions are summarized together with illustrations of the typical shapes of each bone from the 12 genotypes. Variability within genotypes was investigated by using the Mahalanobis D2 distance--a measure of the difference between two points representing multivariate data--from the group mean. A series of variants were detected ranging from grossly abnormal bones to bones showing subtle differences localized to specific regions. Examples of the variants found are illustrated.     

Effects of parity on pelvic size and shape dimorphism in Mus

The pelvis is a sexually dimorphic structure and although the causes of that dimorphism have long been studied, relatively little is known regarding the effects of partuitive events on the magnitude of that dimorphism. Here, we use a sample of Mus musculus domesticus to contrast dimorphism in body length and os coxae size and shape between males and parous and nulliparous females. We also test for correlations between relative litter size (L/M) and relative offspring size (O/M) with body length and os coxae size and shape in parous females. Males had greater body length than nulliparous females but were not different from parous females. Females as a whole had the largest os coxae, with parous females having the largest and males the smallest. Os coxae shape was also significantly different between groups and was most divergent between parous females and males than between nulliparous females and males. Os coxae shape differences between females are associated with differences in body length between females and O/M is correlated with os coxae shape in parous females such that females with the largest offspring have the most divergent shapes along the relative warp one axis. Pelvic shape differences between males and females were consistent with previous findings in other taxa which identify the pubo‐ischial complex as the primary region of dimorphism. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.     

Structural study of spongiosa tissue in growing sheep.

A study was made of 160 long bones taken from 40 native Merino sheep of both sexes. These animals, which represented uniform growth (mean growth-curve values), were divided into four groups which were slaughtered consecutively at 0, 45, 105 and 270 days old (0, 6.4, 15 and 38.5 weeks, respectively). The following bones were studied; humerus, femur, tibia and os coxae. Thin lamellae taken from the metaphyses of the bones obtained were fixed, decalcified and stained with hematoxylin-eosin to assess the development of the various components of growing bony tissue. The bones studied followed the same maturation pattern; the os coxae proved to be the best histological indicator in differentiating the age of the animals studied.     

Long bones of the primate upper limb: Monomorphic or dimorphic?

An important debate has been taking place during the last few years concerningAustralopithecus afarensis: can the Hadar sample be ascribed to one highly dimorphic species or should it be separated into two distinct taxa? A similar problem occurs with the Middle Miocene cercopithecoids from East Africa: does this material belong to one dimorphic group or can we recognize two different taxa? The study of the long bones of the upper limb of many extant primates suggests that the extremities in different taxa are very distinctive but that within taxa the joints are weakly or are not morphologically dimorphic although they can be markedly size dimorphic. The main shape and size differences which can be ascribed to sexual dimorphism occur in the shafts of the long bones. Examinations have been made inHomo, Pan, Gorilla, Pongo, Hylobates, Alouatta, Cebus, Saimiri, Ateles, Nasalis, Presbytis and some Cercopithecinae. It appears, then, that the extremities of the bones are shape monomorphic. If the same relationships occurred in the fossil record, then the differences observed in the hominid fossil elbow joints at Hadar suggest that at least two different taxa are represented in the collection. In addition, among the cercopithecoid material assigned toVictoriapithecus from Maboko and Nyakach in East Africa, we recognize two distinct elbow morphologies indicating that two different taxa occur in the localities.     

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. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.     

Variation in the Habiline Crania – Must it be Taxonomic?

The problem of whether the hominid fossil sample of habiline specimens is comprised of more than one species has received much attention in paleoanthropology. The core of this debate has significant implications about when and how variation must be explained by taxonomy. In this paper, we examine the problem of whether the observed variation in habiline sample must be interpreted to reflect species differences. We test the null hypothesis of no difference by examining the degree of variability in habiline sample in comparison with other single-species early hominid fossil samples from Sterkfontein and Swartkrans (Sterkfontein is earlier than the habiline sample; Swartkrans may be within the habiline time span). We use the standard error test for this analysis, a sampling statistic based on the standard error of the slope of regressions between pairs of specimens that relates all of the homologous measurements each pair shares. We show that the null hypothesis for the habiline sample cannot be rejected. The similarities of specimen pairs within the habiline sample are not more than those observed between the specimens in the two australopithecine samples we analyzed.     

Taphonomy of the fossil hominid bones from the Acheulean site of Castel di Guido near Rome, Italy

Castel di Guido near Rome is one of the few open air Middle Pleistocene European sites that has yielded hominid skeletal remains associated with fossil fauna and Acheulean implements. The fossil hominid bones include two femoral shafts, respectively designated Castel di Guido-1 (CdG-1) and CdG-2, an occipital fragment (CdG-3), a right maxilla lacking teeth (CdG-4), a portion of right parietal (CdG-5), a right temporal (CdG-6), and a fragment of left parietal vault (CdG-7). CdG-1 through CdG-4 were collected in 1979-1982 on the surface, together with fossil fauna, where ploughing incised fossiliferous tuffaceous sands. Excavations conducted in the same area from 1980 to 1990 led to the discovery of CdG-5, CdG-6 and CdG-7 within the tuffaceous sands, which were shown to overlay a bone-bearing paleosurface, with abundant evidence of hominid activities. The Castel di Guido hominid assemblage poses intriguing taphonomic questions. The analysis of the physical evidence offered by the bone surfaces, reported in the present study, indicates that the hominid skeletal remains were heavily fragmented before fossilization and exposed to carnivores and rodents, as well as to trampling and/or friction in abrasive sediment. Although definitive conclusions cannot be reached on the basis of the available evidence, it is possible that clusters of incisions localized on specific regions of the Castel di Guido fossil hominid bones might reflect deliberate human manipulations.     

Hominid carpal,metacarpal, and phalangeal bones recovered from the Hadar formation: 1974–1977 collections

The fossil hominid hand bone collection from the Pliocene Hadar Formation, Ethiopia, is described anatomically. These hand bones, all from A.L. (Afar Locality) 333 and 333w, constitute the largest sample of hominid manus remains thus far recovered from the Plio-Pleistocene of Africa.     

Virtual reconstruction of the Neandertal lower limbs with an estimation of hamstring muscle moment arms

A major problem of fossil hominid analysis is a lack of complete specimens. Many individual specimens have been damaged by the effects of diagenesis and excavation. Significant advances in the field of three dimensional image processing (3D) have enabled the creation of accurately scaled reconstructions of individual fossil bones using mirrored parts of the same fossil bone or human/fossil hominid equivalents. This study presents, for the first time, a method to reconstruct a 3D virtual model of the lower limb of the Neandertal using different bones from different fossil remains (Spy II, Neandertal 1 and Kebara 2) and integrating them into a single model of the Neandertal lower limb. A biomechanical analysis of the model was performed, including computer graphics visualization of the results, motion displacement graphs and muscle moment arms. The overall method has been implemented into an open-source customized software (lhpFusionBox) developed for the biomechanical study of the musculoskeletal system.     

Habiline variation: A new approach using STET

The problem of whether the hominid fossil sample of habiline specimens is comprised of more than one species has received much attention in paleoanthropology. The core of this debate has critical implications about when and how variation can be explained by taxonomy. In this paper, we examine the problem of whether the observed variation in habiline samples reflects species differences. We test the null hypothesis of no difference by examining the degree of variability in habiline sample in comparison with other single-species early hominid fossil samples from Sterkfontein and Swartkrans (Sterkfontein is earlier than the habiline sample, Swartkrans may be within the habiline time span). We developed a new method for this examination, which we call STandard Error Test of the null hypothesis of no difference (STET). Our sampling statistic is based on the standard error of the slope of regressions between pairs of specimens, relating all of the homologous measurements that each pair shares. We show that the null hypothesis for the habiline sample cannot be rejected. The similarities of specimen pairs within the habiline sample are not more than those observed between the specimens in the australopithecine samples we analyzed.     

The differential frequency of preservation of early hominid wrist and hand bones

A survey of hominid hand and wrist bones of Plio-Pleistocene fossil hominid sites in Africa was undertaken. There are 101 specimens in total, from 7 sites. Carpals are most rarely preserved, but certain elements such as the capitate tend to be more frequently preserved than others. There is a preservation rate cline from proximal to distal in the hand, proximal elements (metacarpals) being numerically better preserved than the distal elements (proximal, middle and distal phalanges, in that order of preservation). The proportion of complete, or nearly complete hand and wrist bones is greater in the distal than in the proximal elements. There is no statistical difference in the frequency of preservation of left and right sides, or in the frequency of preservation of proximal and distal ends of individual bones, although there is a tendency for proximal ends to occur more frequently than distal ends. The incidence of hand and wrist bones in fossil deposits is low compared with that of other post-cranial skeletal elements (with the exception of foot bones, where the incidence is similar). This could be accounted for by depositional factors, but preparation techniques and differential collection of specimens may play a role.     

柳江人身体大小和形状——体重、身体比例及相对脑量的分析

发现于广西柳江的更新世晚期人类化石除1具完整的头骨外,还包含有右侧髋骨、骶骨、两段股骨及若干件椎骨。根据各方面的特征分析,初步认定这些化石属于同一个体。这一有利条件为我们比较准确地获取与该个体身体大小和形状有关的指标数据提供了可能。本文通过对柳江人头骨及复原骨盆的测量,计算了柳江人的身高、体重、身体比例、相对脑量等。在此基础上分析了柳江人的身体大小和形状。本研究发现:柳江人化石所代表的个体具有适应温暖气候环境的纤细型身体比例,代表相对脑量的EQ指数5.602大于金牛山、山顶洞等中国更新世中、晚期化石人类,而与包括港川人在内的更新世末期及现代人类的EQ指数接近。柳江人体重52.0kg小于金牛山、山顶洞、尼安德特人等生活在高纬度地区的化石人类,而与港川、非洲的KNM-ER3883、KNM-ER3733等生活在温暖环境的古人类接近。作者认为这些发现除说明柳江人生活的气候环境外,还提示柳江人身体大小、比例及相对脑量与更新世末期及现代人类接近。     

Foot bones from Omo: implications for hominid evolution

We reanalyze a hominid talus and calcaneus from Omo dating to 2.2 mya and 2.36 mya, respectively. Although both specimens occur at different localities and times, both tarsals articulate well together, suggesting a single taxon on the basis of size and function. We attribute these foot bones to early Homo on the basis of their morphology. The more modern-like tarsal morphology of these Omo foot bones makes them very similar to a talus from Koobi Fora (KNM-ER 813), a specimen attributed to Homo rudolfensis or Homo erectus. Although the Omo tarsals are a million years younger than the oldest known foot bones from Hadar, both localities demonstrate anatomical differences representing two distinct morphological patterns. Although all known hominid tarsals demonstrate clear bipedal features, the tarsal features noted below suggest that biomechanical changes did occur over time, and that certain features are associated with different hominid lineages (especially the robust australopithecines).     

Classification of a 300,000-year-old dental crown of the upper loamy deposit of the Bad Canstatter travertine zone

Hominid dental remains were recovered in association with fossil bones and artifacts during systematic excavations in a loamy deposit located between the two travertine zones T4 and T5 at Stuttgart-Bad Cannstatt, Southwest Germany. Direct dating of a hominid tooth crown with thermoluminescence resulted in a date of 300 kya, which is in agreement with the Holstein Interglacial floral and faunal composition of this layer. The specimen is a lower left canine with hypoplastic morphology. This interpretation is supported by thorough assessment of its overall morphology, comparative metric evaluation, and by scanning electron microscopy analyses of the enamel prisms. Additional microstructural comparison of these dental remains with a tooth from the same site, but derived from a Cervidae specimen supported the distinct differences between both teeth. Here we discuss both the classification and significance of the specimen's evolutionary position as well as compare this specimen with stomatologic results from previous palaeopathological research.     

The influence of mass,volume and density on the frequency of recovery of fossil hominid hand and wrist bones

A study of the mass, volume and density of each of the wrist and hand bones of male and female human skeletons was undertaken. It was found that the mass and volume (i.e. size) of the bones are well correlated with the relative frequencies of preservation ofAustralopithecus and earlyHomo wrist and hand bones from fossil hominid sites in Africa. In general, the larger the bone, the greater its preservation frequency. In contrast to findings on bovid bones, the density of hand and wrist bones is not well correlated with the frequency of such bones recovered from these sites. These findings may be explained in terms of the agents of deposition of the bones, the physical nature of the deposit, and the methods of extraction of the fossils from the deposit.     

The Taung endocast: a reply to Holloway

Indices of rostrality (ir, ir') are developed to assess the extent to which the medial end of the lunate sulcus (L) is rostrally positioned in photographs and figures of lateral views of primate brains and endocasts, and indices are determined for chimpanzees, SK 1585 and the Taung endocast. Ir quantifies the extent of rostrality as it has traditionally been viewed (in A-P projections) while ir' takes dorsal curvature into account. The ir of the feature that I have identified as the lunate sulcus of Taung is within one standard deviation of the mean ir for Pan and its ir' is within 1.5 standard deviations from the mean ir' for Pan. Both findings are compatible with my earlier statement that the medial end of the lunate sulcus of the Taung endocast is in a pongid-like position. Use of stereoplotting to transfer the position of L from chimpanzee endocasts and brains to australopithecine endocasts is critically assessed: Holloway stereoplotted five chimpanzee brains and then transferred their mean coordinates that describe the lunate sulcus to the Taung endocast. If stereoplotting successfully transfers the extent to which L is rostrally located, one would expect the mean L of Pan and its transferred counterpart in Taung to have identical index values of rostrality. However, the ir of the lunate sulcus that Holloway located on Taung is over two standard deviations lower than the mean ir for the five chimpanzees he stereoplotted to determine its angular coordinates, and Holloway's ir' for Taung is one standard deviation lower than the five chimpanzees' mean ir'. These discrepancies are shown to be due to shape differences, and it is concluded that stereoplotting should not be used to transfer sulci between differently shaped endocasts without correcting for these differences. I also reply to Holloway's criticisms of my use of L/H indices, palpation, techniques for sampling endocasts, and illustration of the Taung endocast. It is shown that there is room on the Taung specimen for the lateral end of L, and the pongid-like sulcal pattern of Taung is reaffirmed. Thus, we do not yet know when human-like sulcal patterns first appeared in the hominid fossil record.     

Effects of size and locomotor adaptations on the hominid pelvis: evaluation of australopithecine bipedality with a new multivariate method

Three pelves and eight innominate bones belonging to the fossil species, Australopithecus africanus, Australopithecus robustus, Homo erectus, and Homo sapiens, have been studied biometrically and compared with those of recent humans and apes. A new method of logarithmic factorial analysis suppresses both the size effects and the size reference on pelvic proportions. In combination with principal component analysis it allows specializations to be dissociated from allometrical variations. Some morphological differences on the hominid pelvis prove to be mainly allometric. However, the pelvic morphology of australopithecines is clearly differentiated from that of the genus Homo (including H. erectus, OH 28, KNMER 3227). A. africanus (Sts 14, MLD 7, AL 288) is nearer the humans than is A. robustus (SK 50, SK 3155), which appears to be more specialized in the australopithecine lineage. The pelvic morphology of A. africanus, as integrated with the articular pelvic-femoral link, appears to be biometrically equivalent to that of humans.     

A 3D quantitative comparison of trapezium and trapezoid relative articular and nonarticular surface areas in modern humans and great apes

The structure and functions of the modern human hand are critical components of what distinguishes Homo sapiens from the great apes (Gorilla, Pan, and Pongo). In this study, attention is focused on the trapezium and trapezoid, the two most lateral bones of the distal carpal row, in the four extant hominid genera, representing the first time they have been quantified and analyzed together as a morphological-functional complex. Our objective is to quantify the relative articular and nonarticular surface areas of these two bones and to test whether modern humans exhibit significant shape differences from the great apes, as predicted by previous qualitative analyses and the functional demands of differing manipulative and locomotor strategies. Modern humans were predicted to show larger relative first metacarpal and scaphoid surfaces on the trapezium because of the regular recruitment of the thumb during manipulative behaviors; alternatively, great apes were predicted to show larger relative second metacarpal and scaphoid surfaces on the trapezoid because of the functional demands on the hands during locomotor behaviors. Modern humans were also expected to exhibit larger relative mutual joint surfaces between the trapezoid and adjacent carpals than do the great apes because of assumed transverse loads generated by the functional demands of the modern human power grip. Using 3D bone models acquired through laser digitizing, the relative articular and nonarticular areas on each bone are quantified and compared. Multivariate analyses of these data clearly distinguish modern humans from the great apes. In total, the observed differences between modern humans and the great apes support morphological predictions based on the fact that this region of the human wrist is no longer involved in weight-bearing during locomotor behavior and is instead recruited solely for manipulative behaviors. The results provide the beginnings of a 3D comparative standard against which further extant and fossil primate wrist bones can be compared within the contexts of manipulative and locomotor behaviors.