Phantom cave snail

The phantom cave snail or phantom cavesnail (Pyrgulopsis texana) is a species of very small freshwater snail with an operculum, an aquatic gastropod in the family Hydrobiidae.

Distribution
This species is endemic to the lower Pecos River basin, Texas, the United States.

Genus transfer
When originally described in 1935, the phantom cave snail was assigned to the genus Cochliopa. Following a detailed examination of shell and anatomical characteristics along with genetic sequencing it was transferred to the genus Pyrgulopsis in 2010.