Expression Types for Two Cercopithecoid Dental Traits (Interconulus and Interconulid) and Their Variation in a Modern Baboon Population

Studies of cercopithecoid systematics include the analysis of quantitative and qualitative dental variation. Much of the qualitative variation involves the expression of cingular remnants on molars. Qualitative variation in the cingular remnant has been defined and described in several ways by researchers. The differences in terminology and definition confound cross-study comparisons. I introduce a formalized typology for two nonmetric molar traits, the interconulus and interconulid. Each trait includes 5 degrees of expression, with written and photographic descriptions for each character state. I scored a large sample (n = 329) of dental casts from a captive breeding colony of savannah baboons (Papio hamadryas sspp.) for the expression types and assessed the variation statistically. The baboon colony shows a large amount of variation in the two traits. Use of these formalized types will facilitate cross-study comparison and analysis, effectively increasing sample sizes and our understanding of the evolution of primate dentitions.