广栖豌豆蚬，软体动物门-瓣鳃纲-真瓣鳃目-球蚬科。维基百科Pisidium is a genus of very small or minute freshwater clams known as pill clams or pea clams, aquatic bivalve molluscs in the family Sphaeriidae, the pea clams and fingernail clams. In some bivalve classification systems, the family Sphaeriidae is referred to as Pisidiidae, and occasionally Pisidium species are grouped in a subfamily known as Pisidiinae.Drawing of the right valve external view of Pisidium moitessierianumDrawing of the right valve internal view ofPisidium moitessierianumDrawing of the right valve lateral view of Pisidium moitessierianumContents [hide] 1 Pisidium and taphonomy2 Extant subgenera and species3 Footnotes4 References5 External linksPisidium and taphonomy[edit]In large enough quantities, the minute shells of these bivalves can have an impact on environmental conditions, and this change in conditions can positively affect the ability of organic remains in the immediate environment to fossilize (one aspect of taphonomy).[1] For exa