Mimic cavesnail
The mimic cavesnail, scientific name Phreatodrobia imitata, is a species of very small or minute freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Hydrobiidae. Distribution
This species is endemic to Texas in the United States, where it is known from only two wells that penetrate the Edwards Aquifer. Type locality is Verstraeten Well, Bexar County, Texas. Description 
The shell has 3.3-3.5 whorls. The average height of the shell is 1.01-1.03 mm. References

Lithoglyphidae
Gastropods described in 1986
Taxonomy articles created by Polbot
Endemic fauna of Texas
Cave snails