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.