74 - Examining Morphological Disparity in North American Wolf-like Canids

Poster Board Number: 74
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Abstract Body : Recent efforts to eradicate wild wolf-like canids (Canidae: Canis) in the United States has drastically impacted population sizes and distributions. Past range overlap among these closely related, ecologically similar taxa may have influenced factors such as prey access and probability of admixture, which then affect skull morphology. In the Southern Great Plains (SGP) of the United States, five Canis taxa historically overlapped. This included the gray wolf (Canis lupus) and red wolf (C. rufus), and the presumably extinct Great Plains wolf (C. lupus nubilus). Current Mexican wolf (C. lupus baileyi) distribution is restricted to sparse releases and recovery area, while coyote (C. latrans) populations have increased. To assess morphological disparity among SGP taxa, we micro-CT scanned adult wolf-like canid crania and mandibles collected in the SGP. Using Stratovan Checkpoint software, 37 landmarks were placed on crania and 27 were placed on right mandibles. Data was analyzed using 3D geometric morphometrics, and following Superimposition, Principal Components Analyses (PCAs) provided overviews of shape variation. Thus far, comparing Mexican wolf and red wolf crania produced principal components (PC1 and PC2) explaining 25.98% and 15.03% of the variance. Visualization using wire frames demonstrated Mexican wolves have a wider zygomatic arch and a wider premaxilla relative to the reference, while red wolves have a more medially compressed arch and premaxilla. For the mandibles, PC1 and PC2 explained 33.1% and 14.8% of variance. Wire frames demonstrated Mexican wolves have a taller coronoid process and more robust mandibular body, while the opposite is true for red wolves. Morphological disparity was not statistically significant for crania (p = 0.06) or mandibles (p = 0.86). These morphologies align with strong ancestral ties between the Mexican wolf and gray wolf, and between red wolves and coyotes. Future work includes assessing the strength of ancestry and environment among additional SGP taxa.