Genus Schizothaerus T. A. Conrad, 1853

(3-4-4-0-21-3-1-24-0-0-0-0-0)
[=Tresus J. E. Gray, 1853]
Ref. Vaught, 1989 p 130
Syn. Schizotheirus P. P. Carpenter, 1872;
Schizothoerus T. A. Conrad, 1856;
Seizocheilus P. P. Carpenter, 1861;
Shizothaerus T. A. Conrad, 1868
[=Tresus J. E. Gray, 1853]
Ref. Abbott, 1974 p 491
Lindner, 1977 p 111
Vokes, 1980 p 138

keenae T. Kuroda & T. Habe, 1950
(3-4-4-0-21-3-1-24-0-1-0-0-0)
[=Tresus nuttallii (T. A. Conrad, 1837)]
Ref. Bernard, 1983 p 40

nuttallii T. A. Conrad, 1837
(3-4-4-0-21-3-1-24-0-2-0-0-0)

bighopensis J. B. Henderson, 1931
(3-4-4-0-21-3-1-24-0-2-1-0-0)
[=Tresus capax (A. A. Gould, 1850)]
Ref. Bernard, 1983 p 40

kissyuensis K. M. Hatai, 1941
(3-4-4-0-21-3-1-24-0-2-2-0-0)
[=Tresus nuttallii (T. A. Conrad, 1837)]
Ref. Bernard, 1983 p 40