title: Sphaerium
text: # Sphaerium
  
  Sphaerium is a genus of very small freshwater clams, aquatic bivalve molluscs in the family Sphaeriidae, known as the fingernail clams. The small clams in this genus are unusual in that many of them, such as Sphaerium corneum, can climb around underwater on aquatic plants, using their long and strong foot.
  
  ## Species
  
  * Subgenus Sphaerium Scopoli, 1777
  
     * Sphaerium corneum (Linnaeus, 1758) – European fingernail clam
  * Subgenus Nucleocyclas Alimov & Starobogatov, 1968
  
     * Sphaerium nucleus (Studer, 1820)
  
     * Sphaerium ovale (A. Férussac, 1807)
  * Subgenus Parasphaerium Alimov & Starobogatov, 1968
  
     * Sphaerium nitidum Clessin, 1876 – Arctic fingernail clam
  * Subgenus Amesoda Rafinesque, 1820
  
     * Sphaerium rivicola (Lamarck, 1818)
  * Subgenus Cyrenastrum Bourguignat, 1854
  
     * Sphaerium solidum (Normand, 1844)
  * Without subgenus
  
     * Sphaerium asiaticum (Martens, 1864)
  
     * Sphaerium bequaerti (Dautzenberg & Germain, 1914) – data deficient (DD)
  
     * Sphaerium cornuta
  
     * Sphaerium novaezelandiae Deshayes, 1854
  
     * Sphaerium rhomboideum (Say, 1822)
  
     * Sphaerium stuhlmanni Martens, 1897 – least concern (LC)
  * Extinct
  
     * †Sphaerium beckmani Russell, 1976
  
     * †Sphaerium florissantense Cockerell, 1906
  