1School of Physical Therapy, Slippery Rock University, 2Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, 3Department of Anatomy and Neurobiology, NEOMED
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For a given skull size, folivorous primates typically have larger and earlier erupting postcanine teeth than frugivorous species. To determine whether these dietary adaptive signals can be discerned at birth, microCT slices and serial histological sections of the crania from 28 perinatal strepsirrhines (17 species) were studied. Presence or absence and stage of maturation of deciduous and permanent maxillary teeth were assessed, and dental sac volumes were measured across species relative to cranial length (prosthion-inion). The total number of permanent teeth present at birth is greatest in Propithecus verreauxi and lorisoids. In these species, dental sacs for nearly all permanent maxillary teeth could be detected at least at the bud stage; in Propithecus each replacement premolar had developed to the bell stage. Lemurids possess the fewest permanent teeth that have progressed to the bud stage or beyond, especially Varecia variegata where only C and P2 are present. Cube roots of dental sac volumes are tightly correlated with cranial length, especially dp4 (R2=0.95). MicroCT slices suggest mineralization of dp4 and M1 is more advanced in the folivorous Propithecus and Hapalemur griseus compared to similar-sized frugivores. Preliminary results also indicate dental sac volumes are proportionately large in Hapalemur and Propithecus. These findings suggest that perinatal dental size and maturation do correlate with diet in strepsirrhines. Specifically, perinatal dental form reflects a folivorous lifestyle in that replacement dentition is relatively precocious (as exemplified by Propithecus) and/or posterior maxillary dentition (dp4 and M1) are relatively enlarged.
This study was supported by a grant from the Pennsylvania State System of Higher Education and NSF grant BCS-0959438.