TY - JOUR
T1 - Relative tooth size at birth in primates
T2 - Life history correlates
AU - Smith, Timothy D.
AU - Muchlinski, Magdalena N.
AU - Bucher, Wade R.
AU - Vinyard, Christopher J.
AU - Bonar, Christopher J.
AU - Evans, Sian
AU - Williams, Lawrence E.
AU - DeLeon, Valerie B.
N1 - Publisher Copyright:
© 2017 Wiley Periodicals, Inc.
PY - 2017/11
Y1 - 2017/11
N2 - 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.
AB - 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.
KW - anthropoid
KW - dental
KW - growth
KW - odontogenesis
UR - http://www.scopus.com/inward/record.url?scp=85027510791&partnerID=8YFLogxK
U2 - 10.1002/ajpa.23302
DO - 10.1002/ajpa.23302
M3 - Article
C2 - 28832934
AN - SCOPUS:85027510791
SN - 0002-9483
VL - 164
SP - 623
EP - 634
JO - American Journal of Physical Anthropology
JF - American Journal of Physical Anthropology
IS - 3
ER -