Relative femoral head size in early hominids.

Relative growth of the human femur head is studied by a logarithmic principal components method. Growth rates differ according to the population sampled and the other body dimensions being compared, and especially according to sex. The results do not support biomechanical assumptions of strongly positive allometry of the femur head, which have been used to argue that the australopithecine hip joint was not relatively small.     

Evolution of Hominid Femur and Tibia: A morphometric approach to the evolutionary research in anthropology

Some theoretical and methodological morphometrical approaches in evolutionary anthropology and paleoanthropology are reviewed in this study. It is shown which are the contemporary possibilities of sophisticated biometrical and biostatistical methods and the role of the morphometrical approach. A new approach, experimental morphometrics, is presented, reflecting recent trends in evolutionary morphology as well as sophisticated biostatistical methods. The approach emphasizes the complex inter-related approach to the data processing and a double nature of morphometric data, i.e. biological and biostatistical one. The practical use of experimental morphometry is given for the two examples of analyses of the evolution of the hominoid and hominid femur and tibia. The hypothesis on a two stage restructuring of morphology of the hominid femur and tibia is supported by experimental results. Two different steps during this restructuring could be recognized: 1) Structural remodelling typical for the origin of hominids and australopithecine evolution, and 2) proportional remodelling of lower limb long bones which is connected with the Australopithecus/Homo transition (i.e. mainly Homo habilis stage). The results confirm the increasing trend of bipedal adaptations on the early hominid lower limb skeleton. Analysis of microevolutionary trends on the Homo sapiens femur and tibia indicates at least three different morphological patterns, Paleolithic, Neolithic and Recent, with numerous specific features in morphology and proportions. Neanderthal morphology is very derived. Upper Paleolithic/Mesolithic/Neolithic transition has a key character for the understanding of post-Paleolithic morphology. A very high sexual dimorphism of the femur and tibia has been demonstrated for Upper Paleolithic and Neolithic populations. Presented at the Foundation of Different Approaches to the Study of Human Evolution edited by B. Sigmon & V.V. Leonovicova-Liblice, September 1–3, 1989     

Survivorship in gracile and robust australopithecines: a demographic comparison and a proposed birth model

The age distributions for the two australopithecine types are examined and found to differ significantly as does the difference in average age at death: 22.9 years for Australopithecus africanus and 18.0 years for Australopithecus robustus. Survivorship curves for the two types are constructed. In addition, the survivorship curve for the australopithecine sample is compared to one group of pre-urban Homo sapiens and found to be much the same, if it is assumed the young australopithecines are not adequately represented. A proposed birth model is presented and it is concluded that both australopithecine types followed a human model of reproduction.     

Petite bodies of the “robust” australopithecines

The “robust” australopithecines are often depicted as having large and powerfully built bodies to match their massive masticatory apparatus, but until 1988 the sample of postcranial remains attributed with certainty to this group was very limited. Almost nothing was known about the body of the East African “robust” australopithecine because taxonomic attribution of the postcrania was so uncertain. The body of the South African “robust” australopithecine had to be reconstructed from about a dozen isolated fragments of postcrania. Now a partial skeleton is attributed with confidence to the East African “robust” group along with several isolated bones. The South African sample has more than tripled. Analyses of this vastly expanded sample reveal that a large portion of postcrania attributed to “robust” australopithecines from Swartkrans Member 1 (35%) are from extraordinarily small-bodied individuals similar in size to a modern Pygmy weighing as little as 28 kg. These small elements include parts from the forelimb, spine, and hindlimb. About 22% of these Swartkrans 1 “robust” australopithecines are about the same size as a modern human weighing about 43 kgs and about 43% are larger than this standard but less than or equal to a 54 kg modern human. Approximately the same pattern is true for the Swartkrans 2 hominids, but taxonomic attribution is less certain. All of the Member 3 specimens are similar in size to the 45 kg standard. The partial skeleton of the East African “robust” australopithecine (KNM-ER 1500) has hindlimb joints that would correspond to a modern human of 34 kgs although the actual weight may be 5 to 10 kgs greater judging from shaft robusticity and forelimb size. The largest postcranial element attributed with some certainty to the East African “robust” australopithecine group (the talus, KNM-ER 1464) is about the same overall size as a modern human of 54 kgs, although its tibial facet is slightly smaller. Although many previous studies have hinted at the possibility that “robust” australopithecines had relatively small bodies, the new fossils provide substantial evidence that these creatures ranged from quite small to only moderate in body size relative to modern humans. These were the petite-bodied vegetarian cousins of our ancestors. Sexual dimorphism in body size appears to be greater than that in modern humans, similar to that in Pan, and less than that in Gorilla or Pongo, although such comparisons are of limited value given the small samples, poorly known body proportions, time averaging, and many other problems.     

The ischium and hip extensor mechanism in human evolution

Although it is commonly stated that the ischia of the late Pliocene–early Pleistocene hominid fossils are long and ape-like, new interpretations show this view to be fallacious. An important new theory proposed by Robinson concludes that the gracile form of early hominid was an efficient biped, but the robust form was a less efficient biped and was adapted for tree climbing. Interpretation of the ischium is crucial to this idea. The present study shows that (1) the gracile and robust australopithecine ischia had similar relative lengths and (2) that the hamstring mechanism was probably very similar in the two forms of South African early hominid.     

Sagittal cresting in the South African australopithecines

The evidence for sagittal cresting, and more generally the position of the temporal lines is reviewed in the South African australopithecine sample. The position of the lines is dependent on both the allometric relation of the masticatory apparatus to cranial size and on individual variation. In the Swartkrans specimens, with generally bigger body size, the influence of allometry predominates, actually overshadowing the influence of individual variation. At Sterkfontein and Makapansgat with generally smaller body size and a resulting smaller allometric ratio, individual variation has a greater influence. Of the eleven adult South African specimens, the four largest are crested. The one smaller crested specimen comes from Sterkfontein. The crested Makapan specimen is intermediate in size. The pattern of australopithecine cresting is somewhat different from other hominoids, and is part of a total morphological pattern suggesting adaptation to a diet requiring powerful crushing during mastication.     

Catch-up growth in the limbs of rats undernourished for different lengths of time during suckling

Male rats were undernourished for one of three periods of time during suckling. They were subjected to undernutrition from birth to 8 days post-partum, birth to 15 days or birth to 22 days. The growth of the humerus, radius, femur and tibia was followed radiographically during the undernutrition and recovery periods. It was found that the lengths of these bones in animals undernourished from birth to 8 days were able to recover completely, while after the two longer periods of undernutrition, the animals were unable to recover. The results are not in complete agreement with those of previous workers and it is suggested that this may be due to differing rates of growth and maturation between the animals used in different studies.     

On a new australopithecine partial endocast.

A newly discovered right parietal/temporal/frontal fragment from an australopithecine natural endocast is described and compared to other australopithecine endocasts. This specimen shows that the central sulcus was arched, rather than straight as previously believed, and reveals frontal lobe convolutions not preserved in other australopithecine endocasts.     

Head posture in the Hominoidea

The angle between the antero-posterior plane of the occipital condyles and a vertical axis at right angles to the Frankfort Horizontal was measured in Homo sapiens, Gorilla, Pan, Pongo and casts of two Neanderthal skulls, the Rhodesian skull and three australopithecine skulls. The angle was much greater in adult Homo sapiens and in the Neanderthal and australopithecine casts than in the adult groups of the three apes. In the immature groups, the angle underwent little change with age in Homo sapiens but in Gorilla and Pan the angle decreased markedly during the growth period. These findings can be readily correlated with the habitual bodily posture of each of the extant genera. In Homo sapiens , an upright posture is adopted early in life while in the African apes the young tend to move by brachiation and thus have an habitual posture of the spine closer to the vertical than in the "knuckle walking" adults. The large value of the angle in the Neanderthal casts also correlates well with the now widely held view that this group has a fully upright posture. However, the finding of a relatively low value for the angle in adult Pongo —a brachiator—runs counter to the general thesis that the angle is a direct reflection of overall posture and casts some doubt upon a conclusion that the large value of the angle in the australopithecine fossils necessarily indicates that these creatures stood upright.     

Growth changes in internal and craniofacial flexion measurements.

Growth changes in both internal and craniofacial flexion angles are presented for Pan troglodytes, Gorilla gorilla, and modern humans. The internal flexion angle (IFA) was measured from lateral radiographs, and the craniofacial flexion angle (CFA) was calculated from coordinate data. Stage of dental development is used as a baseline for examination of growth changes and nonparametric correlations between flexion angles and dental development stage are tested for significance. In Gorilla, the IFA increases during growth. The IFA is relatively stable in Pan and modern humans. Pan and Gorilla display an increase in the CFA. However, this angle decreases during growth in modern humans. Flexion angles were derived from coordinate data collected for several early hominid crania. Measurements for two robust australopithecine crania indicate strong internal flexion. It has been suggested that cerebellar expansion in this group may relate to derived features of the posterior cranial base. In general, australopithecine crania exhibit craniofacial flexion intermediate between great apes and modern humans. The "archaic" Homo sapiens specimen from Kabwe is most similar to modern humans.     

The Hox gene Ultrabithorax modulates the shape and size of the third leg of Drosophila by influencing diverse mechanisms

The developmental mechanisms that regulate the relative size and shape of organs have remained obscure despite almost a century of interest in the problem and the fact that changes in relative size represent the dominant mode of evolutionary change. Here, I investigate how the Hox gene Ultrabithorax (Ubx) instructs the legs on the third thoracic segment of Drosophila melanogaster to develop with a different size and shape from the legs on the second thoracic segment. Through loss-of-function and gain-of-function experiments, I demonstrate that different segments of the leg, the femur and the first tarsal segment, and even different regions of the femur, regulate their size in response to Ubx expression through qualitatively different mechanisms. In some regions, Ubx acts autonomously to specify shape and size, whereas in other regions, Ubx influences size through nonautonomous mechanisms. Loss of Ubx autonomously reduces cell size in the T3 femur, but this reduction seems to be partially compensated by an increase in cell numbers, so that it is unclear what effect cell size and number directly have on femur size. Loss of Ubx has both autonomous and nonautonomous effects on cell number in different regions of the basitarsus, but again there is not a strong correlation between cell size or number and organ size. Total organ size appears to be regulated through mechanisms that operate at the level of the entire leg segment (femur or basitarsus) relatively independently of the behavior of individual subpopulations of cells within the segment.     

Head and neck anthropometry, vertebral geometry and neck strength in height-matched men and women

Women have an increased incidence of whiplash injury and neck pain compared to men. Physical and numerical models represent one avenue to explore and potentially explain these gender differences, but a valid model of the female neck does not yet exist. A fundamental question in the development of a female neck model is whether female necks are simply scaled versions of male necks, or whether there are significant inter-gender geometrical differences. The goal of this study was to quantify differences in head and neck geometry and neck strength in pairs of male and female subjects matched for standing height and neck length. Based on 14 matched pairs of men and women, we found that most head and neck anthropometric parameters were significantly smaller in females compared to males. Moreover, gender differences in a number of neck anthropometry parameters (an average of 9-16% smaller in females) were larger than differences in head anthropometry parameters (an average of 3-6% smaller in females). Female vertebrae between C3 and C7 were significantly smaller than male vertebrae in the anterior-posterior dimension (p < 0.012) but not in the medial-lateral dimension (p > 0.07). Female necks were also significantly weaker than male necks (32% weaker in flexion and 20% weaker in extension; p < 0.001), and these strength differences corresponded well to those predicted solely from the observed geometric differences. These results demonstrate that male and female necks are not geometrically similar and indicate that a female-specific model will be necessary to study gender differences in neck-related disorders.     

A new pelvic fragment from swartkrans and the relationship between the robust and gracile australopithecines

A recently discovered hominid pelvic fragment from Swartkrans (SK 3155) is described in detail with particular reference to the relationship of the two presently recognized forms of australopithecines in South Africa. Results of this examination and metrical analysis indicate that the acetabulum and iliac blade of the early hominids are similar to Homo sapiens except for a unique pattern of traits: a relatively small sacral articular surface, a relatively small acetabulum, a relatively large iliac fossa, and wide lateral splaying of the iliac blades. The new Swartkrans fossil expresses these traits more strongly than does the gracile australopithecine (Sts 14) and is therefore somewhat less similar to Homo sapiens but it is very unlike any pongid.     

The australopithecines in review

Over the past 75 years since the discovery of the first australopithecine at Taung in southern Africa there has been a growing realisation that there is no simple, linear ancestor-descendant relationship connecting the australopithecines to laterHomo. There are currently at least ten recognised species of australopithecine, including two species of earlyHomo, that have been recently transferred to the genusAustralopithecus. These known species span the period between about 4.2-1.2 Ma and throughout the majority of this period there are multiple contemporaneous hominin species in eastern and southern Africa. This contribution reviews current knowledge about the australopithecine species and their inferred relationships to each other and to the genusHomo. At present it is impossible to resolve the phylogenetic relationships of the australopithecines with any degree of confidence. There is a growing realisation of the ‘bushy’ nature of hominin evolution throughout the australopithecine period and also of the inevitability that additional early hominin species remain to be discovered. Paper submitted for inclusion in the Proceedings of the International Symposium of the Ramón Areces Foundation “Evolution of the Human Family: State of the Art” held in Madrid on the 11–13 March, 1998     

云南西瓦古猿头骨的初步研究

本文对1978年12月在云南禄丰石灰坝煤窑发现的第一个古猿头骨化石作了描述和比较,归属为云南西瓦古猿类型。由于它在形态上保留一些原康修尔猿的性质和显示出较多的相似于猩猩的特征,所以作者认为它可能代表后两者的中间环节。同时,作者又发现这个头骨具有接近于南方古猿粗壮种的性质,因此认为云南西瓦古猿与南方古猿粗壮类型可能有亲缘关系。     

Size and shape of the australopithecine pelvic bone

The recovery of several specimens allows to have a good knowledge of australopithecine pelvic bone anatomy. But despite this, differences of opinion still exist regarding locomotory interpretations. The aim of this paper is to present results of a new morphometric analysis of australopithecine pelvic bones to try to understand the reasons of this situation. It appears that australopithecines exhibit the same overall architectural pattern as extant humans, the hominid pattern, just as all African apes also exhibit the same pongid pattern. But, in this pattern, it is possible to clearly depict two subpatterns corresponding to both generaAustralopithecus andHomo. Locomotory interpretations depend on the fact that some studies emphasize traits related to the hominid pattern (concluding then on modern bipedalism) and others focus on trains characterizing australopithecine sub-pattern (concluding then on non-modern bipedalism).     

Cranial capacity estimates for Olduvai Hominid 7

Estimation of cranial capacity for Olduvai Hominid (OH) 7 is determined from external parietal dimensions using multiple regressions calculated from an australopithecine grade sample. Capacity estimates for OH 7 (580–600 cc) are much lower than usually claimed. While differences in reconstruction may account for the varying estimates, a regression based only on undistorted and unreconstructed values, as well as a direct comparison of dimensions with other Homo habilis specimens, supports the smaller capacity determination.     

Metrical analysis of the basicranium of extant hominoids and Australopithecus

The size and shape of the basicranium (seen in norma basilaris) in Homo, Gorilla, Pan, Pongo, and Australopithecus have been studied by recording the relative disposition of midline and bilateral bony landmarks. Fifteen linear measurements and two angles were used to relate the landmarks. The relatively longer and narrower cranial base of Gorilla, Pan, and Pongo is clearly contrasted with the wider, shorter cranial base in Homo sapiens. When the same observations were made on two “robust” and two “gracile” australopithecine crania, marked differences were found between the taxa. In the two “robust” specimens, the foramen magnum is located relatively further forward, and the axis of the petrous temporal bone is aligned more nearly with the coronal plane than in the two “gracile” crania. The implications of this apparent parallelism in basicranial morphology between Homo sapiens and the “robust” australopithecines are discussed.