The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Osteonal bone density in the mandibles of West African colobines


1Anthropology, University of Florida, 2Anthropology, The Ohio State University

Friday 8:45-9:00, Galleria North Add to calendar

The sympatric West African red colobus (Procolobus badius) and king colobus (Colobus polykomos) are distinguishable by aspects of both skeletal morphology and diet. At Taï Forest, king colobus consume greater amounts of mature leaves than do red colobus, while also heavily exploiting the ligneous seeds pods of Pentaclethera macrophylla. These observations suggest that the Colobus polykomos diet is significantly tougher than that of P. badius, perhaps resulting in greater daily masticatory and ingestive activity in the former. Under the hypothesis that greater load frequency predisposes mandibular bone to fatigue failure, we expect remodeling activity to be greater in primates processing tougher diets.

We prepared thin sections from the postcanine mandibular corpus in four adult specimens each of red and king colobus for examination of secondary osteonal density and area. We employed analysis of variance to examine osteonal bone variation associated with species, sex, cortical plates (buccal vs. lingual) and region (alveolar process vs. basal corpus). Variation is primarily idiosyncratic; that is, we observed no regional, sex or species effects. There is significant variation between cortical plates, which reflects higher osteon density in the buccal cortex, particularly in P. badius.

Thin sections of mandibular bone in the hard-object specialist Cercocebus atys yield values for osteon density below those observed for these colobines. In this particular case, the high-load environment inferred for durophagy is not associated with elevated remodeling activity. These data underscore the uncertain relationship between food material properties and metabolic activity in mandibular bone.

Supported by NSF BCS-0922429 and 0921770.

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