The 85th Annual Meeting of the American Association of Physical Anthropologists (2016)


Relative tooth size at birth in primates: Life history and dietary correlates

TIMOTHY D. SMITH1,2, MAGDALENA N. MUCHLINSKI3, CHRISTOPHER J. BONAR4, SIAN EVANS5,6, LAWRENCE WILLIAMS7, CHRISTOPHER J. VINYARD8 and VALERIE B. DELEON9.

1School of Physical Therapy, Slippery Rock University, 2Department of Anthropology, University of Pittsburgh, 3Department of Anatomy and Neurobiology, University of Kentucky, 4Dallas Zoo, Dallas, 5Dumond Conservancy, Miami, 6Department of Biological Sciences, Florida International University, 7Michale E. Keeling Center for Comparative Medicine and Research, UT MD Anderson Cancer Center, 8Department of Anatomy and Neurobiology, NEOMED, 9Department of Anthropology, University of Florida

April 16, 2016 , Atrium Ballroom A/B Add to calendar

Dental eruption schedules in part reflect dietary specialization; life history correlates have also been implicated. Here we examine a sample of 52 perinatal primates (28 species) to determine how soon dietary or life history variables correlate to relative tooth size. Cadaveric primates obtained from natural captive deaths were studied using serial histological sectioning. Volumes of deciduous premolars (dp2-dp4) and permanent molars (M1-2/3) of the upper jaw were calculated based on serial cross-section tooth germ area. Most variables were strongly correlated with cranial length (CL), thus residuals from CL were calculated with least squares regressions (e.g., relative dental volume). ANCOVA revealed significant differences among primates based on diet. In particular, folivorous strepsirrhines have the relatively largest M1 and total molar volume, although the difference is not significant after phylogeny was considered (PGLS). Relative dental volume significantly correlated with relative gestation length (dp3, R=-0.50; p<0.05), and relative neonatal mass (dp4, R=-0.58) but not relative weaning age. However, the only significant PGLS result was with relative gestation length. Results reveal a negative relationship between deciduous premolar size and gestation length (M1 has a weak correlation, R=-0.1), suggesting a strategy by which primates with shorter gestation lengths grow deciduous teeth more rapidly. These results might be explained by the strategy of rapid development of permanent dentition in strepsirrhines. Indeed, a plot of relative total molar volume versus relative gestation length reveals a positive association in strepsirrhines compared to a negative slope in anthropoids.

This study was supported by NSF # BCS-1231350; NSF # BCS-1231717; NSF # BCS-0959438; BCS-0820751; P40 OD010938; NIH # P51OD011106.