Tentative Checklist of Aquatic Snails of Indiana
Current taxonomic issues and perspectives make developing a good checklist is a challenge. The need for more extensive collections and suitable molecular analysis is great. A further challenge is that aquatic snails display a great deal of morphological plasticity – regionally or due to changes in size/age. Data are needed to assess local and regional geographic variability in order to better define species and their ranges.
As a result, any checklist must be considered to be tentative as well as any key to species. The names of some species below may have been changed or considered to be otherwise by some authorities. :-)
The list below is a conservative working list. The list is based primarily on two sources: Pyron et al. (2008) and Nature Serve (2021). This list has 51 species, but probably up to 7 may no longer be extant, and two species are exotic. Pyron et al. (2008) stated that in Indiana, there are "36 species that are widespread, abundant, and globally secure, including two exotics." The true number is probably closer to Pyron et al. (2008), but is truly unknown. Dillon et al. 2019 indicates 40 species from their survey which did not include the northern part of the state (not in the "catchment of the Ohio River basin above ORM 920").
The Ohio Division of Wildlife has a picture key: Freshwater Snails of Ohio Field Guide (link opens as a pdf). It is from a next-door state and while it does not have all our possible species, it can be useful for iNaturalist identifications. In the list below, (OH) indicates the Indiana species is in the Ohio guide. Many species are also pictured at the Freshwater Gastropods of North America Project species list.