Humeral correlates of forelimb elevation in four West African cercopithecid monkeys.
OBJECTIVE
We previously found that differing degrees of forelimb flexion, elevation, and abduction during nonlocomotor foraging activities covaried with scapular morphology among four sympatric cercopithecids. The purpose of this study is to investigate whether features of the proximal humerus are similarly related to forelimb elevation during foraging.


METHODS
Our sample consists of humeri (n = 42) of adult Cercocebus atys, Cercopithecus diana, Colobus polykomos, and Piliocolobus badius collected from Côte d'Ivoire's Taï National Park. Features of the proximal humerus known to correspond with varying degrees of forelimb mobility were examined using a combination of 2-dimensional caliper-based indices and 3-dimensional analyses.


RESULTS
Some features of the proximal humerus are consistent with the varying frequencies of forelimb elevation during foraging. For instance, the red colobus (P. badius) has a variety of features consistent with more pronounced shoulder mobility and forelimb flexibility including a wider, more distally projecting deltoid plane, greater tuberosity positioned below the humeral head articular surface, and larger intertuberosity angle.


CONCLUSIONS
The colobines, particularly P. badius, display a number of humeral and scapular features indicative of greater arm flexion, elevation, and abduction compared to the two cercopithecines. We conclude that idiosyncrasies in forelimb use during foraging are reflected in functionally relevant features of the cercopithecid proximal humerus, highlighting that postural behavior, in additional to locomotor behavior, can exert selective pressures on primate skeletal form. This result should provide for more informed reconstructions of the full positional repertoires in fossil taxa.
Department of Anthropology, The Ohio State University, 4034 Smith Laboratory, 174 West 18th Ave, Columbus, Ohio, 43210-1106.
Noah T
NT
Dunham
Department of Anthropology, The Ohio State University, 4034 Smith Laboratory, 174 West 18th Ave, Columbus, Ohio, 43210-1106.
Erin E
EE
Kane
Department of Anthropology, The Ohio State University, 4034 Smith Laboratory, 174 West 18th Ave, Columbus, Ohio, 43210-1106.
W Scott
WS
McGraw
D000818:Animals; D000885:Anthropology, Physical; D002520:Cercopithecidae / Q000033:anatomy & histology* / Q000502:physiology*; D007560:Cote d'Ivoire; D006811:Humerus / Q000033:anatomy & histology* / Q000502:physiology*; D013045:Species Specificity
Cercocebus; Cercopithecus; Colobus; Piliocolobus; shoulder morphology