This paper addresses the taxonomic status of the extinct large-bodied sea mink Neogale macrodon. Since the early twentieth century, bones of this mink have been found commingled with those of the extant mink, Neogale vison, in Maine’s prehistoric archaeological sites. These two size classes of mink have been described as separate species and as sexually dimorphic size variants of N. vison. A century later, researchers revisited this dispute using data from North American modern and archaeological mink skulls, along with limited postcranial bones, and decided in favor of two species. However, this conclusion was challenged.

We return to the discussion by focusing on postcranial bones, which have advantages over skulls for metric analyses. We considered historical evidence for mink morphology and behavior and determined that, although the two forms shared the same habitat, our large number of identified specimens (NISP) of mink (NISP > 1200) contained no detectable evidence for interbreeding. We conclude that the sea mink was an emerging marine fissiped, transitioning from an undetermined N. vison ancestor in a manner analogous to the polar bear (Ursus maritimus) and the sea otter (Enhydra lutris). Lastly, we suggest N. macrodon became extinct during the nineteenth century under heavy pressure from market hunting.