Mustela stromeri
Mustela stromeri is an extinct medium-sized species of mustelid and was the earliest known true species of polecat. It is ancestral to all modern ferrets and polecats.
Taxonomy
Mustela stromeri, along with a number of other mustelid species, was first described by Hungarian geologist Tivadar Kormos in 1934, in the large village of Beremend. Its smaller size suggests that the subgenus Putorius evolved at a more recent date, presumably during the Villafranchian.Mustela stromeri is ancestral to modern ferrets and polecats. The steppe polecat and European polecat evolved from Mustela stromeri in the Middle Pleistocene, whereas the black-footed ferret probably evolved from the former around 0.5 to 2 million years ago.