Complex sentence: Chrysallidinae is a taxonomic group of very small sea snails, one of eleven recognized subfamilies of the gastropod family Pyramidellidae (according to the taxonomy of Ponder & Lindberg 1997).
Split into simpler sentences: Chrysallidinae is a taxonomic group of very small sea snails in the family Pyramidellidae. Chrysallidinae has been one of eleven recognized subfamilies of the gastropod family Pyramidellidae (according to the taxonomy of Ponder & Lindberg 1997).