Patterns of cranial sexual dimorphism in certain groups of extant hominoids

O’Higgins, P.; Moore, William; Johnson, David R.; McAndrew, T J; Flinn, R. M.

doi:10.1111/j.1469-7998.1990.tb04041.x

Cited by 44 publications

(34 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our results support numerous studies that have confirmed sexual dimorphism of cranial dimensions in gorillas (O'Higgins et al, 1990;Wood et al, 1991;O'Higgins and Dryden, 1993;Uchida, 1996;Lockwood, 1999;Schaefer et al, 2004). These studies have also shown that there is a high variability of dimorphism among the dimensions studied.…”

Section: Sexual Dimorphism In Head Sizesupporting

confidence: 94%

Using photogrammetry and color scoring to assess sexual dimorphism in wild western gorillas (Gorilla gorilla)

Breuer

Robbins

Boesch

2007

American J Phys Anthropol

View full text Add to dashboard Cite

Investigating sexual dimorphism is important for our understanding of its influence on reproductive strategies including male-male competition, mate choice, and sexual conflict. Measuring physical traits in wild animals can be logistically challenging and disruptive for the animals. Therefore body size and ornament variation in wild primates have rarely been quantified. Gorillas are amongst the most sexually dimorphic and dichromatic primates. Adult males (silverbacks) possess a prominent sagittal crest, a pad of fibrous and fatty tissue on top of the head, have red crest coloration, their saddle appears silver, and they possess a silverline along their stomach. Here we measure levels of sexual dimorphism and within-male variation of body length, head size, and sexual dichromatism in a population of wild western gorillas using photogrammetry. Digital photogrammetry is a useful and precise method to measure sexual dimorphism in physical traits yielding sexual dimorphism indices (ISD), similar to those derived from traditional measurements of skeletal remains. Silverbacks were on an average 1.23 times longer in body length than adult females. Sexual dimorphism of head size was highest in measures of crest size (max ISD: 60.4) compared with measures of facial height (max ISD: 24.7). The most sexually dimorphic head size measures also showed the highest within-sex variation. We found no clear sex differences in crest coloration but there was large sexual dichromatism with high within-male variation in saddle coloration and silverline size. Further studies should examine if these sexually dimorphic traits are honest signals of competitive ability and confer an advantage in reproductive success.

show abstract

Section: Sexual Dimorphism In Head Sizesupporting

confidence: 94%

Using photogrammetry and color scoring to assess sexual dimorphism in wild western gorillas (Gorilla gorilla)

Breuer

Robbins

Boesch

2007

American J Phys Anthropol

View full text Add to dashboard Cite

show abstract

“…Overall, the results of this study introduce many interesting avenues for future investigation, while highlighting the caution with which studies of ontogeny have to be approached. As an example, one of the authors has shown that adult sexual dimorphisms can differ to greater or lesser degree, not only between different primate species but also between modern human populations (O’Higgins et al. 1989, 1990a, 1990b; O’Higgins, 1989).…”

Section: General Conclusionmentioning

confidence: 99%

A geometric morphometric study of regional differences in the ontogeny of the modern human facial skeleton†

2002

View full text Add to dashboard Cite

This study examines interpopulation variations in the facial skeleton of 10 modern human populations and places these in an ontogenetic perspective. It aims to establish the extent to which the distinctive features of adult representatives of these populations are present in the early post natal period and to what extent population differences in ontogenetic scaling and allometric trajectories contribute to distinct facial forms. The analyses utilize configurations of facial landmarks and are carried out using geometric morphometric methods. The results of this study show that modern human populations can be distinguished based on facial shape alone, irrespective of age or sex, indicating the early presence of differences. Additionally, some populations have statistically distinct facial ontogenetic trajectories that lead to the development of further differences later in ontogeny. We conclude that population-specific facial morphologies develop principally through distinctions in facial shape probably already present at birth and further accentuated and modified to variable degrees during growth. These findings raise interesting questions regarding the plasticity of facial growth patterns in modern humans. Further, they have important implications in relation to the study of growth in the face of fossil hominins and in relation to the possibility of developing effective discriminant functions for the identification of population affinities of immature facial skeletal material. Such tools would be of value in archaeological, forensic and anthropological applications.The findings of this study underline the need to examine more deeply, and in more detail, the ontogenetic basis of other causes of craniometric variation, such as sexual dimorphism and hominin species differentiation.

show abstract

“…Skeletal dimorphism is not uniformly expressed as a simple function of body mass dimorphism in primates (Oxnard, 1987;O'Higgins et al, 1990;Plavcan, in press), and in fact appears to be very complex in the pattern of its expression both within and among species. In most species, measurements of the brain case, basicranium, and orbits tend to show less dimorphism than measurements of the face and jaws ( Fig.…”

Section: "Reverse Dimorphism"mentioning

confidence: 99%

Sexual dimorphism in primate evolution

Plavcan

2001

Am. J. Phys. Anthropol.

164

175

View full text Add to dashboard Cite

Sexual dimorphism is a pervasive phenomenon among anthropoid primates. Comparative analyses over the past 30 years have greatly expanded our understanding of both variation in the expression of dimorphism among primates, and the underlying causes of sexual dimorphism. Dimorphism in body mass and canine tooth size is familiar, as is pelage and "sex skin" dimorphism. More recent analyses are documenting subtle differences in the pattern of skeletal dimorphism among primates. Comparative analyses have corroborated the sexual selection hypotheses, and have provided a more detailed understanding of the relationship between sexual selection, natural selection, and mating systems in primates. A clearer picture is emerging of the relative contribution of various selective and nonselective mechanisms in the evolution and expression of dimorphism. Most importantly, recent studies have shown that dimorphism is the product of changes in both male and female traits. Developmental studies demonstrate the variety of ontogenetic pathways that can lead to dimorphism, and provide additional insight into the selective mechanisms that influence dimorphism throughout the lifetime of an animal. Evidence from the fossil record suggests that dimorphism probably evolved in parallel twice, and the dimorphism in some extinct hominoids probably exceeded that of any living primate. Our advances in understanding the behavioral/ecological correlates of dimorphism in living primates have not improved our ability to reconstruct social systems in extinct species on the basis of dimorphism alone, beyond the inference of polygyny or intense male-male competition. However, our understanding of the behavioral/ecological correlates of growth and development, and of the expression of dimorphism as a function of separate changes in male and female traits, offers great potential for inferring evolutionary changes in behavior over time

show abstract

Patterns of cranial sexual dimorphism in certain groups of extant hominoids

Cited by 44 publications

References 22 publications

Using photogrammetry and color scoring to assess sexual dimorphism in wild western gorillas (Gorilla gorilla)

Using photogrammetry and color scoring to assess sexual dimorphism in wild western gorillas (Gorilla gorilla)

A geometric morphometric study of regional differences in the ontogeny of the modern human facial skeleton†

Sexual dimorphism in primate evolution

Contact Info

Product

Resources

About