Trimusculus is the only genus in the family Trimusculidae.[5] Trimusculidae, the button snails, is the only family in the superfamily Trimusculoidea,[6] a superfamily of false limpets. These are marine pulmonate gastropod mollusks in the cladeEupulmonata.[6]
Trimusculids are not very closely related to the siphonariids, another family of marine air-breathing false-limpets. The trimusculids are in the clade Eupulmonata, and are quite closely related to air-breathing land snails.
^Schmidt F. C. (1818). Vers. Einth. Conch. [teste Marschall 1873, Nomen. zool., 143]; Moeller (1832). Isis (Oken), 1832: 132.
^WoRMS (2010). Trimusculus F.C. Schmidt, 1818. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138565 on 2011-01-09