Timothy D Smith1,2, Magdalena N Muchlinski3, Wade R Bucher1, Christopher J Vinyard4, Christopher J Bonar5, Sian Evans6,7, Lawrence E Williams8, Valerie B DeLeon9. 1. School of Physical Therapy, Slippery Rock University, Slippery Rock, Pennsylvania 16057. 2. Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania. 3. Center for Anatomical Sciences, University of North Texas, Health Science Center, Fort Worth, Texas 76107. 4. Department of Anatomy and Neurobiology, NEOMED, Rootstown, Ohio 44272. 5. Dallas Zoo, Dallas, Texas 75203. 6. DuMond Conservancy, Miami, Florida 33170. 7. Department of Biological Sciences, Florida International University, Miami, Florida 33199. 8. Department of Veterinary Sciences, UT MD Anderson Cancer Center, Michale E. Keeling Center for Comparative Medicine and Research, Bastrop, Texas 78602. 9. Department of Anthropology, University of Florida, Gainesville, Florida 32611.
Abstract
OBJECTIVES: Dental eruption schedules have been closely linked to life history variables. Here we examine a sample of 50 perinatal primates (28 species) to determine whether life history traits correlate with relative tooth size at birth. MATERIALS AND METHODS: Newborn primates were studied using serial histological sectioning. Volumes of deciduous premolars (dp2 -dp4 ), replacement teeth (if any), and permanent molars (M1-2/3 ) of the upper jaw were measured and residuals from cranial length were calculated with least squares regressions to obtain relative dental volumes (RDVs). RESULTS: Relative dental volumes of deciduous or permanent teeth have an unclear relationship with relative neonatal mass in all primates. Relative palatal length (RPL), used as a proxy for midfacial size, is significantly, positively correlated with larger deciduous and permanent postcanine teeth. However, when strepsirrhines alone are examined, larger RPL is correlated with smaller RDV of permanent teeth. In the full sample, RDVs of deciduous premolars are significantly negatively correlated with relative gestation length (RGL), but have no clear relationship with relative weaning age. RDVs of molars lack a clear relationship with RGL; later weaning is associated with larger molar RDV, although correlations are not significant. When strepsirrhines alone are analyzed, clearer trends are present: longer gestations or later weaning are associated with smaller deciduous and larger permanent postcanine teeth (only gestational length correlations are significant). DISCUSSION: Our results indicate a broad trend that primates with the shortest RGLs precociously develop deciduous teeth; in strepsirrhines, the opposite trend is seen for permanent molars. Anthropoids delay growth of permanent teeth, while strepsirrhines with short RGLs are growing replacement teeth concurrently. A comparison of neonatal volumes with existing information on extent of cusp mineralization indicates that growth of tooth germs and cusp mineralization may be selected for independently.
OBJECTIVES: Dental eruption schedules have been closely linked to life history variables. Here we examine a sample of 50 perinatal primates (28 species) to determine whether life history traits correlate with relative tooth size at birth. MATERIALS AND METHODS: Newborn primates were studied using serial histological sectioning. Volumes of deciduous premolars (dp2 -dp4 ), replacement teeth (if any), and permanent molars (M1-2/3 ) of the upper jaw were measured and residuals from cranial length were calculated with least squares regressions to obtain relative dental volumes (RDVs). RESULTS: Relative dental volumes of deciduous or permanent teeth have an unclear relationship with relative neonatal mass in all primates. Relative palatal length (RPL), used as a proxy for midfacial size, is significantly, positively correlated with larger deciduous and permanent postcanine teeth. However, when strepsirrhines alone are examined, larger RPL is correlated with smaller RDV of permanent teeth. In the full sample, RDVs of deciduous premolars are significantly negatively correlated with relative gestation length (RGL), but have no clear relationship with relative weaning age. RDVs of molars lack a clear relationship with RGL; later weaning is associated with larger molar RDV, although correlations are not significant. When strepsirrhines alone are analyzed, clearer trends are present: longer gestations or later weaning are associated with smaller deciduous and larger permanent postcanine teeth (only gestational length correlations are significant). DISCUSSION: Our results indicate a broad trend that primates with the shortest RGLs precociously develop deciduous teeth; in strepsirrhines, the opposite trend is seen for permanent molars. Anthropoids delay growth of permanent teeth, while strepsirrhines with short RGLs are growing replacement teeth concurrently. A comparison of neonatal volumes with existing information on extent of cusp mineralization indicates that growth of tooth germs and cusp mineralization may be selected for independently.
Authors: Sarah M Zehr; Richard G Roach; David Haring; Julie Taylor; Freda H Cameron; Anne D Yoder Journal: Sci Data Date: 2014-07-22 Impact factor: 6.444
Authors: Kelsey Paddock; Larissa Zeigler; Brianna Harvey; Kristen A Prufrock; Jordan M Liptak; Courtney M Ficorilli; Russell T Hogg; Christopher J Bonar; Sian Evans; Lawrence Williams; Christopher J Vinyard; Valerie B DeLeon; Timothy D Smith Journal: Anat Rec (Hoboken) Date: 2020-01-01 Impact factor: 2.064