Cyclas similis Say, 1817
Say, 1817. Nich. Encyc. 2: pl. 1, fig. 9.

Sphaerium simile — F.C. Baker (1928), Mackie et al. (1980), Turgeon et al. (1998), Lee & Ó Foighil (2002), Mackie (2007), ... ITIS (2012), Clewing et al. (2013), Ram et al. (2014), Bespalaya et al. (2017), Saito et al. (2022)
Sphaerium (Amesoda) sulcata — Thiele (1934)
Sphaerium sulcatum — Herrington (1962)
Sphaerium (s.s.) simile — Clarke (1973), Burch (1975), Cooley & Ó Foighil (2000)
Sphaerium (Amesoda) simile — Lee & Ó Foighil (2003), Bespalaya et al. (2023)
“Sphaerium (S)” simile — Fuentealba-Jara et al. (2017)

Cyclas sarratogea Lamarck, 1818
Lamarck, 1818. Hist. Natur. Anim. sans Vert. 5: 560.

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Cyclas sulcata Lamarck, 1818
Lamarck, 1818. Hist. Natur. Anim. sans Vert. 5: 560.

Sphaerium simile — F.C. Baker (1928), Mackie (2007)
Sphaerium (Amesoda) sulcata — Thiele (1934)
Sphaerium sulcatum — Herrington (1962)
Sphaerium (s.s.) simile — Clarke (1973), Burch (1975)
Sphaerium “sulcatum” — Korniushin & Glaubrecht (2002)

Cyclas (Amesoda) lasmampsis Rafinesque, 1820
Rafinesque, 1820. Ann. Gén. Sci. Phys. 5 (13): 319, pl. 82, figs. 19-21 [also as ‘Ameroda [sic] lasmampsis’].

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Cyclas solida De Kay, 1843
De Kay, 1843. Zool. New York 5: 229, pl. 25, fig. 265.

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Cyclas gigantea Prime, 1852
Prime, 1852. Proc. Boston Soc. Nat. Hist. 4: 157.
Prime, 1853. Proc. Boston Soc. Nat. Hist. 4: 282.

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Cyclas ponderosa Prime, 1852
Prime, 1852. Proc. Boston Soc. Nat. Hist. 4: 157.
Prime, 1853. Proc. Boston Soc. Nat. Hist. 4: 282.

Sphaerium (s.s.) simile — Burch (1975)

Sphaerium crassum Sterki, 1901
Sterki, 1901. Nautilus 14(12): 140.

Sphaerium crassum — F.C. Baker (1928)
Sphaerium sulcatum — Herrington (1962)
Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium lineatum Sterki, 1910
Sterki, 1910. Nautilus 23(11): ??.

Sphaerium sulcatum — Herrington (1962)
Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium sulcatum var. albescens Sterki, 1916
Sterki, 1916. Ann. Carnegie Mus. 10(3/4): ??.
(intro'd as intra-sp. of Cyclas sulcata Lamarck, 1818)

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium sulcatum var. insigne Sterki, 1916
Sterki, 1916. Ann. Carnegie Mus. 10(3/4): ??.
(intro'd as intra-sp. of Cyclas sulcata Lamarck, 1818)

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium sulcatum var. planatum Sterki, 1916
Sterki, 1916. Ann. Carnegie Mus. 10(3/4): 432.
(intro'd as intra-sp. of Cyclas sulcata Lamarck, 1818)

Sphaerium simile planatum — F.C. Baker (1928)
Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium fallax Sterki, 1930
Sterki, 1930. Nautilus 43(3): 93.

Sphaerium sulcatum — Herrington (1962)
Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium sulcatum dakotense Sterki, 1930
Sterki, 1930. Nautilus 43(3): 95.
(intro'd as intra-sp. of Cyclas sulcata Lamarck, 1818)

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Cyclas lasmanpsis Lamarck, 1835
Lamarck, 1835. unknown publication: ??.
‘Rafinesque’ Ferussac, 1835. Mag. Zool. 5(59-60): 29.
(error for Cyclas (Amesoda) lasmampsis Rafinesque, 1820)

Sphaerium (s.s.) simile — Burch (1975)

Cyclas sarratoga Hanley, 1843
‘Lamarck’ Hanley, 1843. Illustr. Descr. Cat. Rec. Bivalve Shells: 90.
(error for Cyclas sarratogea Lamarck, 1818)

Cyclas saratogea Prime, 1865
‘Lamarck’ Prime, 1865. Smithsonian Misc. Coll. (145): 34.
(error for Cyclas sarratogea Lamarck, 1818)

Cyclas elliptica Prime, 1870
‘Férussac’ Prime, 1870. Amer. J. Conch. 5: ??. [nomen nudum]

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium sulcatum decisum Brooks & Herrington, 1944
‘Sterki’ Brooks & Herrington, 1944. Nautilus 57(3): ??. [nomen nudum]
(intro'd as intra-sp. of Cyclas sulcata Lamarck, 1818)

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium sulcatum obscurum Brooks & Herrington, 1944
‘Sterki’ Brooks & Herrington, 1944. Nautilus 57(3): ??. [nomen nudum]
(intro'd as intra-sp. of Cyclas sulcata Lamarck, 1818)

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Sphaerium sulcatum sculptum Brooks & Herrington, 1944
‘Sterki’ Brooks & Herrington, 1944. Nautilus 57(3): ??. [nomen nudum]
(intro'd as intra-sp. of Cyclas sulcata Lamarck, 1818)

Sphaerium (s.s.) simile — Burch (1975)
Sphaerium simile — Mackie (2007)

Cyclas similas Burch, 1975
‘Say’ Burch, 1975. Freshw. Sphaer. North Amer.: 48.
(error for Cyclas similis Say, 1817)