Lateral Enamel Formation and Life History in New World Monkeys
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Series/Report no.:2015 Edward F. Hayes Graduate Research Forum. 29th
Aspects of dental development such as first molar eruption, crown formation time, and occlusal enamel formation rates are associated with life history variation in primate posterior dentition. However, relationships between enamel formation in anterior teeth and life history in living species have not been previously examined, even though several studies of fossil hominins have focused on anterior teeth. This study explores the relationship between life history variation and estimated lateral enamel formation time, as well as percent of perikymata, incremental growth lines in the enamel, in the cervical half of the crown in the incisors of twelve extant species of New World monkeys or platyrrhines, as no research has investigated the latter. New World monkeys were chosen due to their high life history diversity. The sample analyzed consists of ten teeth from each of the four incisor tooth types for all twelve species. Only incisors with mammelons or with very minimal wear were included. Perikymata were counted using a measuring microscope and periodicities, the length of time it takes to form each perikyma, were taken from literature. Measures of life history and related variables were also taken from the literature and include: encephalization quotient, age at weaning, age at reproductive maturation, average lifespan, brain mass, and body mass. Results of phylogenetically corrected simple linear regressions show that estimated lateral enamel formation time and percent of perikymata in the cervical half of the crown are significantly correlated with all variables. However, significance is not the same for all incisor types. These results suggest that estimated lateral enamel formation time and percent of perikymata in the cervical region in incisors reflect important aspects of life history in platyrrhines and may be useful in the prediction of life history profiles of fossil platyrrhines.
Poster Division: Arts, Humanities, and Social Sciences: 2nd Place (The Ohio State University Edward F. Hayes Graduate Research Forum)