Pomatiopsis lapidaria



     Scientists have had trouble agreeing on the habitat of Pomatiopsis lapidaria.  Pilsbry, Shimek, and Stinson all claimed that the Slender Walker is terrestrial (DeWitt, 1952), while Baker (1931) argues that the snail is more amphibious in nature.  He supported his argument with the observation that the snail will stay submerged during floods, rather than move to the higher ground (Baker, 1931).  Ameel (1938) supports Baker’s claim by asserting that many cercariae that require an aquatic host infect the Slender Walker.  Complements of Aydin Írstan (Pomatiopsis lapidaria shell, operculum closed)

     Regardless of the exact classification, it seems that scientists can agree that Pomatiopsis lapidaria lives close to, if not in, freshwater.  Dundee (1957) claims that there are three common features to all Slender Walker habitats: “(1) a very moist substratum with enough sand to prevent it from becoming muck, (2) shade, and (3) fresh water”.  Dundee (1957) also points out the snail’s ability to stay in these regions throughout the seasons.   The snail seems to get enough oxygen circulating through its gills to remain submerged during certain spring floods (Abbott, 1948)(Baker, 1931).   Dewitt (1952) observes that it makes no attempt to find its way to drier land.  During hot summer days, it seeks the shelter of moist aquatic vegetation or damp leaves (Baker, 1931).  Observation in the laboratory showed it is able to survive long periods without water to help survive the sweltering summer days (Ameel, 1938).  During the winter, the Slender Walker searches for depressions in the ground or other crevices to hibernate until warm weather returns (DeWitt, 1952).  They are able to close their opercula, or covering to their shell, to help protect themselves from harsh conditions (DeWitt, 1952).

     Pomatiopsis lapidaria is only found in North America (Abbott, 1948).  It has not been able to establish itself west of the Rocky Mountains (Abbott, 1948).  It is found as far north as Ontario and as far south as Florida in the Southern United States (Abbott, 1948).

Click here for a distribution map of the Slender Walker.