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Objectives: Interpretations of the primate and human fossil record often rely on the estimation of somatic dimensions from bony measures. Both somatic and skeletal variation have been used to assess how primates respond to environmental change. However, it is unclear how well skeletal variation matches and predicts soft tissue. Here, we empirically test the relationship between tissues by comparing somatic and skeletal measures using paired measures of pre‐ and post‐mortem rhesus macaques from Cayo Santiago, Puerto Rico. Materials and Methods: Somatic measurements were matched with skeletal dimensions from 105 rhesus macaque individuals to investigate paired signals of variation (i.e., coefficients of variation, sexual dimorphism) and bivariate codependence (reduced major axis regression) in measures of: (1) limb length; (2) joint breadth; and (3) limb circumference. Predictive models for the estimation of soft tissue dimensions from skeletons were built from Ordinary Least Squares regressions. Results: Somatic and skeletal measurements showed statistically equivalent coefficients of variation and sexual dimorphism as well as high epiphyses‐present ordinary least square (OLS) correlations in limb lengths (R2 >0.78, 0.82), joint breadths (R2 >0.74, 0.83) and, to a lesser extent, limb circumference (R2 >0.53, 0.68). Conclusion: Skeletal measurements are good substitutions for somatic values based on population signals of variation. OLS regressions indicate that skeletal correlates are highly predictive of somatic dimensions. The protocols and regression equations established here provide a basis for reliable reconstruction of somatic dimension from catarrhine fossils and validate our ability to compare or combine results of studies based on population data of either hard or soft tissue proxies. [ABSTRACT FROM AUTHOR]

Objectives: Estimation of body mass from skeletal metrics can reveal important insights into the paleobiology of archeological or fossil remains. The standard approach constructs predictive equations from postcrania, but studies have questioned the reliability of traditional measures. Here, we examine several skeletal features to assess their accuracy in predicting body mass. Materials and Methods: Antemortem mass measurements were compared with common skeletal dimensions from the same animals postmortem, using 115 rhesus macaques (male: n = 43; female: n = 72). Individuals were divided into training (n = 58) and test samples (n = 57) to build and assess Ordinary Least Squares or multivariate regressions by residual sum of squares (RSS) and AIC weights. A leave‐one‐out approach was implemented to formulate the best fit multivariate models, which were compared against a univariate and a previously published catarrhine body‐mass estimation model. Results: Femur circumference represented the best univariate model. The best model overall was composed of four variables (femur, tibia and fibula circumference and humerus length). By RSS and AICw, models built from rhesus macaque data (RSS = 26.91, AIC = −20.66) better predicted body mass than did the catarrhine model (RSS = 65.47, AIC = 20.24). Conclusion: Body mass in rhesus macaques is best predicted by a 4‐variable equation composed of humerus length and hind limb midshaft circumferences. Comparison of models built from the macaque versus the catarrhine data highlight the importance of taxonomic specificity in predicting body mass. This paper provides a valuable dataset of combined somatic and skeletal data in a primate, which can be used to build body mass equations for fragmentary fossil evidence. [ABSTRACT FROM AUTHOR]

Objective: Reconstructing the social lives of extinct primates is possible only through an understanding of the interplay between morphology, sexual selection pressures, and social behavior in extant species. Somatic sexual dimorphism is an important variable in primate evolution, in part because of the clear relationship between the strength and mechanisms of sexual selection and the degree of dimorphism. Here, we examine body size dimorphism across ontogeny in male and female rhesus macaques to assess whether it is primarily achieved via bimaturism as predicted by a polygynandrous mating system, faster male growth indicating polygyny, or both. Methods: We measured body mass in a cross‐sectional sample of 362 free‐ranging rhesus macaques from Cayo Santiago, Puerto Rico to investigate size dimorphism: (1) across the lifespan; and (2) as an outcome of sex‐specific growth strategies, including: (a) age of maturation; (b) growth rate; and (c) total growth duration, using regression models fit to sex‐specific developmental curves. Results: Significant body size dimorphism was observed by prime reproductive age with males 1.51 times the size of females. Larger male size resulted from a later age of maturation (males: 6.8–7.8 years vs. females: 5.5–6.5 years; logistic model) and elevated growth velocity through the pre‐prime period (LOESS model). Though males grew to larger sizes overall, females maintained adult size for longer before senescence (quadratic model). Discussion The ontogeny of size dimorphism in rhesus macaques is achieved by bimaturism and a faster male growth rate. Our results provide new data for understanding the development and complexities of primate dimorphism. [ABSTRACT FROM AUTHOR]