Novisuccinea sp. 4, Novasuccinea n. sp. minnesota b
Basis for Former Listing
The Iowa Pleistocene ambersnail is an extremely rare landsnail currently known from 17 sites within a very limited range in southeastern Minnesota and northeastern Iowa (Frest 1991). Five small populations occur in Fillmore and Olmsted counties. This taxon is believed to have been more widespread during the Wisconsin glaciation over 12,000 years ago, but now survives only on small patches of habitat. The rarity of this species led to its classification as endangered in Minnesota in 1996.
Basis for Delisting
When the Iowa Pleistocene ambersnail received species status in 1991, it was based on differences in shell and genitalic characteristics. Using these characteristics alone for identification can be inaccurate because of considerable variations in these features within and between populations of the same or closely related species, or between species of different snail genera. No anatomical or molecular data were used to confirm that it is a distinct species. In addition, designation of the taxon has never gone through peer review, nor has it received a Latin name. Therfore, designation as a threatened species was no longer deemed appropriate. The Iowa Pleistocene ambersnail was delisted in 2013.