Myonera kaiwa C.D. de Castro Oliveira& R.S. Absalão, 2009
Cardiomya kashimana T.A. Okutani & K. Sakurai,1964
Cardiomya kavranensis (FOSSIL) (Slodkewitsch, 1938 †)
Cuspidaria kerguelensis (E.A. Smith, 1885)
Cuspidaria kirki (FOSSIL) (F.W. Hutton, 1873 †)
Cardiomya knudseni (J.A. Allen & R.E. Morgan,1981)
Cardiomya korjakensis (FOSSIL) Volobueva, 1994 †
Cardiomya kronokiensis (FOSSIL) Pronina, 1969 †
Cuspidaria krylovae J.A. Allen, 2011
Cuspidaria kurodai T.A. Okutani, 1975
Soyomya kurohijii (T.A. Okutani, 1972)
Cuspidaria kyushuensis T.A. Okutani, 1962
Myonera lamellifera (W.H. Dall, 1881)
Cuspidaria lamellosa (G.O. Sars, 1878)
Cardiomya lanieri (A.M. Strong& L.G. Hertlein, 1937)
Cuspidaria latesulcata R. Tate, 1887
Bathyneaera laticella (W.H. Dall, 1886)
Plectodon lepidus B.A. Marshall, 2002
Cardiomya levifrons (B.C. Cotton, 1930)
Plectodon ligula (M. Yokoyama, 1922)
Myonera limatula (W.H. Dall, 1881)
Myonera lischkei (E.A. Smith, 1891)
Cuspidaria lubangensis J. Poutiers, 1981
Cuspidaria luymesi J. Knudsen, 2005
Krylovina lynnae P.H. Valentich-Scott& E.V. Coan, 2012
Cuspidaria macrorhynchus E.A. Smith, 1895
Cardiomya majnatschensis (FOSSIL) (Ilyina, 1962 †)
Cardiomya makiyamai (FOSSIL) (K. Kanehara, 1937 †)
Cardiomya mansfieldi (FOSSIL) A.A. Olsson & A. Harbison,1953 †
Cuspidaria maxima P. Dautzenberg & H. Fischer,1897
Cuspidaria media A.E. Verrill & K.J. Bush,1898
Cuspidaria meridionalis (E.A. Smith, 1885)
Cuspidaria meteoris E.M. Krylova, 2006
Cuspidaria microrhina W.H. Dall, 1886
Cuspidaria minima (E.N. Egorova, 1993)