Dental maturation, eruption, and gingival emergence in the upper jaw of newborn primates.
*Tooth Eruption/physiology; Animals; anthropoid; Dentition; development; Gingiva/*anatomy & histology/*growth & development; haplorhine; Jaw/*anatomy & histology/physiology; Newborn; Odontogenesis/physiology; Permanent; Primates/*anatomy & histology/*growth & development; Species Specificity; strepsirrhine; Tarsius; teeth
In this report we provide data on dental eruption and tooth germ maturation at birth in a large sample constituting the broadest array of non-human primates studied to date. Over 100 perinatal primates, obtained from natural captive deaths, were screened for characteristics indicating premature birth, and were subsequently studied using a combination of histology and micro-CT. Results reveal one probable unifying characteristic of living primates: relatively advanced maturation of deciduous teeth and M1 at birth. Beyond this, there is great diversity in the status of tooth eruption and maturation (dental stage) in the newborn primate. Contrasting strategies in producing a masticatory battery are already apparent at birth in strepsirrhines and anthropoids. Results show that dental maturation and eruption schedules are potentially independently co-opted as different strategies for attaining feeding independence. The most common strategy in strepsirrhines is accelerating eruption and the maturation of the permanent dentition, including replacement teeth. Anthropoids, with only few exceptions, accelerate mineralization of the deciduous teeth, while delaying development of all permanent teeth except M1. These results also show that no living primate resembles the altricial tree shrew (Tupaia) in dental development. Our preliminary observations suggest that ecological explanations, such as diet, provide an explanation for certain morphological variations at birth. These results confirm previous work on perinatal indriids indicating that these and other primates telegraph their feeding adaptations well before masticatory anatomy is functional. Quantitative analyses are required to decipher specific dietary and other influences on dental size and maturation in the newborn primate.
Smith Timothy D; Muchlinski Magdalena N; Jankord Kathryn D; Progar Abbigal J; Bonar Christopher J; Evans Sian; Williams Lawrence; Vinyard Christopher J; DeLeon Valerie B
Anatomical record (Hoboken, N.J. : 2007)
2015
2015-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1002/ar.23273" target="_blank" rel="noreferrer noopener">10.1002/ar.23273</a>
Relative tooth size at birth in primates: Life history correlates.
*anthropoid; *dental; *growth; *odontogenesis; Animals; Anthropology; Deciduous/*anatomy & histology; Female; Maxilla/anatomy & histology; Molar/anatomy & histology; Newborn/*physiology; Odontogenesis/*physiology; Physical; Primates/*physiology; Tooth
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 (dp(2) -dp(4) ), replacement teeth (if any), and permanent molars (M(1-2/3) ) 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.
Smith Timothy D; Muchlinski Magdalena N; Bucher Wade R; Vinyard Christopher J; Bonar Christopher J; Evans Sian; Williams Lawrence E; DeLeon Valerie B
American journal of physical anthropology
2017
2017-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1002/ajpa.23302" target="_blank" rel="noreferrer noopener">10.1002/ajpa.23302</a>