Body size and body shape in early hominins - implications of the Gona Pelvis
ABSTRACT Discovery of the first complete Early Pleistocene hominin pelvis, Gona BSN49/P27, attributed to Homo erectus, raises a number of issues regarding early hominin body size and shape variation. Here, acetabular breadth, femoral head breadth, and body mass calculated from femoral head breadth are compared in 37 early hominin (6.0-0.26 Ma) specimens, including BSN49/P27. Acetabular and estimated femoral head sizes in the Gona specimen fall close to the means for non-Homo specimens (Orrorin tugenesis, Australopithecus africanus, Paranthropus robustus), and well below the ranges of all previously described Early and Middle Pleistocene Homo specimens. The Gona specimen has an estimated body mass of 33.2kg, close to the mean for the non-Homo sample (34.1kg, range 24-51.5kg, n=19) and far outside the range for any previously known Homo specimen (mean=70.5kg; range 52-82kg, n=17). Inclusion of the Gona specimen within H. erectus increases inferred sexual dimorphism in body mass in this taxon to a level greater than that observed here for any other hominin taxon, and increases variation in body mass within H. erectus females to a level much greater than that observed for any living primate species. This raises questions regarding the taxonomic attribution of the Gona specimen. When considered within the context of overall variation in body breadth among early hominins, the mediolaterally very wide Gona pelvis fits within the distribution of other lower latitude Early and Middle Pleistocene specimens, and below that of higher latitude specimens. Thus, ecogeographic variation in body breadth was present among earlier hominins as it is in living humans. The increased M-L pelvic breadth in all earlier hominins relative to modern humans is related to an increase in ellipticity of the birth canal, possibly as a result of a non-rotational birth mechanism that was common to both australopithecines and archaic Homo.
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- "studies on other hindlimb joint surfaces (e.g., Jungers, 1988). Other research on primate pelvic scaling has focused on the influences of obstetrical requirements and neonatal brain size on pelvic shape (Leutenegger, 1974, 1982; Tague, 2005) especially in relation to the evolution of bipedality and relatively large brain size in early hominin species (Reynolds, 1931; Dart, 1949; Le Gros Clark, 1955; Day, 1973; Lovejoy et al., 1973; Brain et al., 1974; McHenry, 1975; Ashton et al., 1981; Berge, 1984; Berge and Kazmierczak, 1986; Rak and Arensburg, 1987; Berge, 1991; Rak, 1991; Fleagle and Anapol, 1992; Rosenberg, 1992; Berge, 1994; Ruff, 1995; MacLatchy, 1996; Macchiarelli et al., 1999; Marchal, 2000; Haeusler, 2002; Lovejoy, 2005; Lovejoy et al., 2009; Weaver and Hublin, 2009; Ruff, 2010). Research on the obstetrical functions of the pelvis has demonstrated that aspects of the bony birth canal—dimensions of the pelvic inlet, midplane, and outlet—differ intra-and interspecifically, with selection favoring females with larger pelvic diameters in species that have large neonates relative to maternal size (Schultz, 1949; Black, 1970; Leutenegger, 1974). "
ABSTRACT: Identification of positional behavior adaptation in the pelvis of primates is complicated by possible confounding effects of body size and phylogeny. Previous work on primate pelvic allometry has focused primarily on sexual dimorphism and its relationship to obstetric constraints in species with large fetal size relative to maternal size. This study investigates patterns of pelvic scaling with a specific aim to understand how pelvic scaling relates to locomotor function. Patterns of scaling of nine pelvic dimensions were examined in a broad comparative sample of 40 species of primates, covering both haplorhines and strepsirrhines, while accounting for phylogenetic nonindependence. Phylogenetic reduced major axis regressions on pelvic scaling patterns suggest that primate-wide patterns are reflected in haplorhine- and strepsirrhine-specific analyses. Many measures scale isometrically with pelvis size, but notably, features of the ilium tend to scale allometrically. As predicted, ilium width and lower ilium cross-sectional area scale with positive allometry, while lower iliac height scales with negative allometry. Further regression analyses by locomotor group suggest that these ilium measures, as well as pubic symphysis and ischium lengths, differ in their scaling patterns according to locomotor mode. These results suggest that scaling differences within primates, when present, are related to functional differences in locomotor behavior and mechanics. This study supports recent work that identifies adaptations to locomotor loading in the ilium and highlights the need for a better understanding of the relationship between pelvic structural mechanics and the mechanical requirements of primate locomotion. Am J Phys Anthropol, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.American Journal of Physical Anthropology 02/2015; 156(4). DOI:10.1002/ajpa.22696 · 2.51 Impact Factor
- "They are a core element for assessing body proportions (Carretero et al., 2012; Holliday, 1997a; Trinkaus et al., 2014). Body size estimates also permit assessments of sexual dimorphism, for those specimens with sexually diagnostic pelvic remains (Plavcan, 2001; Ruff, 2010; Trinkaus, 1980). For these reasons, it is desirable to maximize the available sample sizes for the estimation of body mass among the Pleistocene humans. "
Article: The Regourdou 1 Neandertal body size[Show abstract] [Hide abstract]
ABSTRACT: Le diamètre de la tête fémorale de Regourdou 1 a été estimé à partir des dimensions de la portion ischiatique de l’acétabulum. Cette mesure permet d’estimer certaines variables corporelles et apporte ainsi de nouvelles données sur la taille et les proportions corporelles des hommes du Pléistocène supérieur. L’estimation de ce diamètre s’est faite en deux étapes. Dans un premier temps, une sphère a été virtuellement conformée sur la surface 3D de l’acétabulum ischiatique. Dans un second temps, le diamètre de la tête fémorale a été estimé à partir du diamètre de la sphère acétabulaire grâce à une formule de régression calculée sur un échantillon de référence moderne. La moyenne des résultats obtenus, comme l’étendue des valeurs, place Regourdou 1 parmi les plus petits Néandertaliens (Europe et Asie du Sud-Ouest confondus), bien que cet individu présente une longueur humérale supérieure à la moyenne de ce même échantillon. Ces caractéristiques permettent de rapprocher Regourdou 1 de Kebara 2, ces deux individus présentant des bras relativement longs par rapport à la taille du corps. Ces nouvelles données sont ainsi l’occasion d’enrichir la variation des proportions corporelles chez les Néandertaliens.Comptes Rendus Palevol 11/2014; DOI:10.1016/j.crpv.2014.07.003 · 1.17 Impact Factor
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- "Femoral head size is correlated with body mass in humans and other hominoids (e.g., see McHenry, 1972; Ruff, 1988; Ruff et al., 1988; Swartz, 1989; Jungers, 1991; Ruff et al., 1991; McHenry, 1992; Rafferty and Ruff, 1994; Ruff, 1998, 2003; Auerbach and Ruff, 2004; Ruff, 2010). "
ABSTRACT: Femoral head size provides important information on body size in extinct species. Although it is well-known that femoral head size is correlated with acetabular size, the precision with which femoral head size can be estimated from acetabular size has not been quantified. The availability of accurate 3D surface models of fossil acetabular remains opens the possibility of obtaining accurate estimates of femoral head size from even fragmentary fossil remains [Hammond et al.,: Am J Phys Anthropol 150 (2013) 565–578]. Here we evaluate the relationship between spheres fit to surface models of the femoral head and acetabulum of a large sample of extant anthropoid primates. Sphere diameters are tightly correlated and scale isometrically. In spite of significant taxonomic and possibly functional differences in the relationship between femoral head size and acetabulum size, percent prediction errors of estimated femoral head size remain low regardless of the taxonomic composition of the reference sample. We provide estimates of femoral head size for a series of fossil hominins and monkeys. Am J Phys Anthropol, 2014. © 2014 Wiley Periodicals, Inc.American Journal of Physical Anthropology 11/2014; 155(3). DOI:10.1002/ajpa.22591 · 2.51 Impact Factor