Knotty pebblesnail
The knotty pebblesnail, scientific name Somatogyrus constrictus, of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the family Hydrobiidae. The taxonomic validity of this species has been questioned; it may represent morphological aberrations of other, valid species. If it is a valid species, it would be assessed as threatened.
