Out of the tropics: a phylogeographic history of the long-tailed weasel,Mustela frenata

Abstract

The long-tailed weasel (Mustela frenata) has the largest distribution of any mustelid in the Western Hemisphere, yet little is known of its genetic history. As a result of its broad distribution, the species provides an excellent model for identifying potential barriers influencing general phylogeographic patterns shared across multiple taxa. Here we used mitochondrial DNA with phylogenetic, phylogeographic, and molecular dating techniques to investigate molecular and geographical structure, as well as demographic history of M. frenata. Samples encompass 38 of the 42 recognized subspecies ranging from southern Canada to Bolivia. Our results suggest that long-tailed weasels are divided into distinct genetic clades, with eastern and western groups present in North America, 2 distinct lineages in Mexico and Central America separated by the trans-Mexican volcanic belt, and 1 clade in South America. Unlike other Mustela in North America, long-tailed weasels appear to have originated in the tropical areas of Mexico and Central America prior to dispersing 1st to the south before also expanding north in the Pleistocene.