The Poweshiek Skipper Project

Terrestrial Snails


 Neohelix alleni (Sampson, 1883)

Western whitelip

This is a large snail, probably the largest or one of the largest in Iowa.  It is found in most of the counties that have been surveyed in Iowa, and I suspect it is found in all areas of Iowa that have original woodlands.

The nomenclature of snails never seems to be stable.  This snail has also been called Tridopsis alleni, and has been called a subspecies of another snail, the snail now called Neohelix albolabris.  In the Baker book this species keys out to Polygrya albolabris alleni.  In the Taft book (Ohio), it is called Tridopsis albolabris alleni.

Natureserve explorer treats this as a separate species, Neohelix alleni, as does Hubricht (as Tridopsis alleni).  The range maps from Hubricht shows alleni found in Iowa but no albolabris.  Based on that I have removed albolabris from the Iowa list.  

In the winter time this snail will seal itself up with a hard plug in the end of the aperture.  I handled this snail a little bit, and it had started to remove the seal.  

The plug is called an epiphragm.  Most snails make these from slime, although a few also produce calcified epiphragms.  


The snail to the right had climbed a tree during a sudden spring rain.  Since the shell is somewhat transparent here, you can see some vermiculations.  That is the lung of the snail.