Geographic variation in skull shape and size of the Pampas fox Lycalopex gymnocercus (Carnivora: Canidae) in Argentina

Abstract

South American foxes are included in the monophyletic genus Lycalopex, with several recent species. Here, the influence of environment about cranial size and shape variations of Lycalopex gymnocercus was explicitly addressed. 3D landmark-based methodology was used to acquire morphometric data. Each record locality was georeferenced and assigned both environmental variables and ecoregion membership. Size and shape changes were analyzed with regression and redundancy analyses, including the study of -spatial autocorrelation. An association of smaller specimens with arid and colder environments was found. Bergmann's rule does not hold for this species. Pampas foxes from humid and warm areas display morphological traits related to more carnivorous diets, whereas those from arid and cold environments should display more hypocarnivorous traits. We found that ˜15% of shape variation explained by environment was independent of allometry, suggesting that both are independent components of the total cranial shape in Pampas foxes.