The factors of morphological variation in craniometrical traits of the American mink (Neovison vison)

Abstract

Craniometrical variation is studied using 441 American mink Neovison vison Baryshnikov and Abramov, 1997 (Schreber, 1777) skulls from nine geographically isolated populations and subpopulations, including domestic minks from a fur farm, with the aim to assess the factors underlying morphological diversity. The geographic origin of populations and potential hybridization between wild minks and domesticated individuals escaping from fur farms are regarded as the main hypotheses of morphological diversity. Sexual size dimorphism is leveled by using nonparametric multidimensional scaling. The results do not show any statistically significant effect of domestic animals from fur farms on the morphological variation in wild minks. The mechanisms limiting wide-range hybridizations based on morphogenetic differences between wild and domestic populations as a result of different selection vectors (stabilizing natural selection in wild populations and breeding) are postulated. Along with such biases, wild mink populations display certain patterns that limit morphological diversity corresponding to well-known biogeography laws and modifying variation. The morphological heterogeneity of introduced populations should be considered taking into account the latest history of formation of prapopulations.