60 - Modularity and the Chondrocranium in Mammals

Poster Board Number: 60
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Co-authors:

Federico Vilaplana Grosso - University of Florida; Valerie DeLeon - University of Florida

Abstract Body : Biological variation in the mammalian skull is the product of diverse developmental mechanisms. The chondrocranium has been identified previously as a driver of growth in the skull. Our research analyzed the craniofacial morphology of primates, bats, and dogs. We recorded three-dimensional coordinate data for landmarks placed on the nose and the cranial base in order to assess the role of the chondrocranium. In all three samples, the variance was analyzed using PCA after Procrustes superimposition. In the bats, 40.4% of the variance was encompassed by PC1 and correlates with cranial index (CI) (R² = 0.9614, p < .0001). In the dogs, 72.2% of the variance was encompassed by PC1 and also correlates with CI (R² = 0.3526, p < .0001). In the primates, 36.1% of the variance was encompassed by PC1 but does not appear to correlate with CI (R² = 0.188, p < .0001). This suggests that there are significant sources of cranial variance in primates that are independent of the overall proportions of the chondrocranium. Additionally, we tested the correlation between the PC1 values of the nose and cranial base. In dogs, the PC1 values of the face and cranial base were highly correlated (R² = 0.6189), whereas in bats and primates this correlation was minimal (R² = 0.0275 and R² = 0.066 respectively). This suggests that the chondrocranium may play different roles in the face and cranial base for these two taxa.