Genus Tresus J. E. Gray, 1853

(3-4-4-0-21-3-1-31-0-0-0-0-0)
Ref. Abbott & Dance, 1982 p 337
Amer. Fish. Soc., 1988 p 40
Bernard, 1983 p 40
Syn. Cryptodon T. A. Conrad, 1837 [not W. H. Turton, 1822];
Schizothaerus T. A. Conrad, 1853
Ref. Abbott, 1974 p 491
Syn. Schizothaerus T. A. Conrad, 1853
Ref. Lindner, 1977 p 111
Syn. Cryptodon T. A. Conrad, 1837 [not W. H. Turton, 1822];
Schizothaerus T. A. Conrad, 1853;
Tresus Walckenaer, 1833
Ref. Vaught, 1989 p 130
Syn. Schizothaerus T. A. Conrad, 1853;
Thresus C. Mayer-Eymar, 1887
Ref. Vokes, 1980 p 138

capax (A. A. Gould, 1850)
(3-4-4-0-21-3-1-31-0-1-0-0-0)
Alaskan Gaper, Fat Gaper, Horse Clam
Ref. Abbott, 1974 p 491 bw
Amer. Fish. Soc., 1988 p 40
Syn. Lutraria (Lutraria) capax A. A. Gould, 1850;
Lutraria (Lutraria) maxima A. T. Middendorff, 1849, not Jonas, 1844;
Lutraria (Lutraria) nuttallii authors [not T. A. Conrad, 1837];
Schizothaerus nuttallii bighopensis J. B. Henderson, 1931
Ref. Bernard, 1983 p 40

nuttalli [nuttallii] (T. A. Conrad, 1837) [T]
(3-4-4-0-21-3-1-31-0-2-0-0-0)
Pacific Coast Gaper, Pacific Gaper
Ref. Abbott, 1974 p 491 bw
Abbott & Dance, 1982 p 337 c
Amer. Fish. Soc., 1988 p 40
Syn. Lutraria (Cryptodon) nuttallii T. A. Conrad, 1837;
Lutraria (Lutraria) capax authors [not A. A. Gould, 1850];
Lutraria (Lutraria) inflata W. Dunker, 1853;
Lutraria (Lutraria) maxima J. H. Jonas, 1844 [not A. T. Middendorff, 1849];
Lutraria (Lutraria) radiata M. Yokoyama, 1920;
Lutraria (Lutraria) sieboldtii L. A. Reeve, 1854;
Schizothaerus keenae T. Kuroda & T. Habe, 1950;
Schizothaerus nuttallii kissyuensis K. M. Hatai, 1941
Ref. Bernard, 1983 p 40

pajaroana authors [not Venus pajaroana T. A. Conrad, 1857]
(3-4-4-0-21-3-1-31-0-3-0-0-0)
Lost Gaper
Ref. Amer. Fish. Soc., 1988 p 40
Bernard, 1983 p 40