Head morphology reflects the introduction history in a globally invasive carnivore—the small Indian mongoose

Abstract Species displaced outside their native range may face new pressures resulting from both environmental gradients and important differences in ecosystem structure. We investigated how this may impact the morphological variation of a globally introduced carnivoran, the small Indian mongoose. Previous research showed size variations in several introduced populations, suggesting that these differences resulted from character release in response to the absence of competition from native species. Here, we contrasted the morphological evolution of indigenous and introduced populations using geometric morphometric approaches on the head system of a large sample of specimens belonging to several regions. Our analyses revealed that differences in size and shape between introduced and native populations do not support hypothesis of character release. These results suggest that morphological variations in introduced populations may reflect the introduction history of the species, rather than evolutionary processes resulting from changes in ecosystem composition.