Abstract # 208:

Scheduled for Friday, June 19, 2015 06:00 PM-08:00 PM: (Cascade AJBCD) Poster Presentation


VARIABILITY SELECTION HYPOTHESIS, WEED MACAQUES, AND BODY SIZE VARIANCE.

H. A. Sullivan III, A. R. Eller and F. J. White
Department of Anthropology, University of Oregon, Eugene, Oregon, USA
line
     Variability Selection Hypothesis (VSH) proposes that early Homo gained adaptive benefit from being flexible in novel or unpredictable climates. Increased intra-taxon variation in body size and the expansion of geographic ranges in early Homo populations suggests greater phenotypic and developmental plasticity. Similar levels of ecological flexibility have been documented in some species of macaques, earning them the moniker of “weed species”. We compare body size variance between weed and non-weed macaques to determine whether intrataxon variation in body size positively correlates with ecological flexibility, as proposed by the VSH. We used two sources of body size data for all available taxa: original data on postcranial osteological body size estimators (seven species, n=49), and published body masses for nineteen species. Fourteen osteometric body size estimators on the humerus, radius, ulna, femur, and tibia were included. All estimators show a tight correlation with body mass: R2 values range from 0.79 to 0.95 with a mean of 0.9. Variance per estimator per species was calculated, as proxies for body mass variance. Averaged estimator variances in non-weed species range from 1.71-11.34, but only 2.26-4.36 within weed species. This data analysis indicates that weed macaques do not exhibit more intrataxon body size variance than non-weeds. Macaques are under-utilized ecological referents for human evolution, and this genus’ diversity is informative for understanding the role of adaptive flexibility in primate evolution generally.