Relative growth of the limbs and trunk in the African apes

Abstract

Examination of relative growth and allometry is important for our understanding of the African apes, as they represent a closely related group of species of increasing body size. This study presents a comparison of ontogenetic relative growth patterns of some postcranial dimensions in Pan paniscus, Pan troglodytes, and Gorilla gorilla. Interspecific proportion differences among the three species are also analyzed. It is stressed that reliable ontogenetic information can only be obtained if subadults are examined-growth data cannot be inferred from static adult scaling. Results indicate that some postcranial relative growth patterns are very similar in the three species, suggesting differential extrapolation of a common growth pattern, whereas for other proportion comparisons the growth trends differ markedly among the species, producing distinct shape differences in the adults. Interspecific shape changes among the three species are characterized by positive allometry of chest girth and negative allometry of body height and leg length. It is suggested that relative decrease of leg length with increasing body size among the African pongids might be expected on biomechanical grounds, in quadrupedal terrestrialism. Relative to body weight or trunk length, the limbs of the bonobo (Pan paniscus) are longer than in the common chimpanzee or the gorilla, with a lower intermembral index. This may most closely resemble the primitive condition for the African apes.

Gait parameters in vertical climbing of captive, rehabilitant and wild Sumatran orang-utans (Pongo pygmaeus abelii)

“…They correspond well with data on mean long bone lengths reported in the literature for the corresponding sex and age groups (e.g. Shea, 1981), which were thus used for all individuals (Table·1). Climbing speed (v) was then calculated by dividing the stride length by the cycle duration (cd).…”

Genetic basis for systems of skeletal quantitative traits: Principal component analysis of the canid skeleton

“…In newborn mammals, the relatively short muzzle (20) is thought to facilitate suckling (21), and their relatively stout neck, trunk, and limbs likely facilitate displacement of competing siblings from nipples. Behaviors necessary in adults associated with functions such as feeding, locomotion, reproduction, and sociality require changes in shape and proportion of the skeletal system during postnatal growth in most or all mammalian species (22)(23)(24). Genetic components regulating the sets of inversely correlated characters of PCs 2, 3, and 4 could account for much of this transformation.…”

Multivariate Cranial Ontogenetic Allometries in Crab-eating, Rhesus and Japanese Macaques.

“…This type of sexual dimorphism is referred to as ontogenetic scaling (Shea, 1985b). The recent usage of ontogenetic scaling (e.g., Shea, 1981Shea, , 1985bShea, , 1988Ravosa and Ross, 1994) differs from that of Gould (1975) in the requirement of sharing a common ontogenetic trajectory. In Gould (1975), ontogenetic scaring is exemplified by the large human brain achieved by a prolonged fetal curve with a high slope, and does not require entire sharing of common growth trajectory.…”