The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


Hominoid dental topography: a possible case for character displacement

MICHAEL A. BERTHAUME.

Department of Engineering, University of Hull

March 26, 2015 3:45, Grand Ballroom C Add to calendar

Dental topography has proved to be a powerful tool in reconstructing mammalian diet from postcanine tooth shape. In extant primates, species with more fibrous diets tend to have higher dental topographic values than species with less fibrous diets. Despite this correlation, there is no deterministic relationship between dental topographic values and dietary categories, e.g. platyrrhines have higher RFI and OPCR scores for a given dietary category than prosimians. Therefore, when reconstructing diet, it is important to compare extinct mammals to their extant relatives. Here, I computed one measure of dental topography, Dirichlet normal energy (DNE), on 61 hominoid molars in order to produce a reference dataset for the hominids. In general, folivorous apes (Gorilla beringei beringei, G.b.graueri) had higher DNE scores than frugivorous apes (Pan paniscus, P. troglodytes trolodytes, P.t.schweinfurthii, Pongo pygmaeus, G.gorilla gorilla), but the difference was not statistically significant. Interestingly, gorillas that live sympatrically with chimpanzees had significantly higher scores than those chimpanzees, and G.b.beringei had similar scores to G.g.gorilla and P.t.schweinfurthii, implying character displacement may be acting on molar shape in hominoids. In addition, contrary to previous studies, subspecies of apes (P.t.schweinfurthii and P.t.troglodytes, G.b.beringei and G.b.graueri) had significantly different scores, illustrating the need to differentiate hominoids on the subspecies level when doing tooth shapes analyses. Results of this study further suggest that dental topography cannot be used to assign hominids to dietary categories, but can be used to compare sympatric species of hominids in order to determine which had more fibrous diets.