Unio nebulosus Conrad, 1834
Conrad, 1834. New Fresh-Water Shells: 28, pl. 3, fig. 7.
Conrad, 1853. Proc. Acad. Nat. Sci. 6: 252.

Lampsilis (sec. Eurynia) nebulosus — Simpson (1900)
Lampsilis (Eurynia) nebulosa — Simpson (1914)
Eurynia (Micromya) nebulosa — Ortmann (1915)
Eurynia nebulosus — Ortmann (1918)
Micromya nebulosa — Ortmann (1924), Ortmann (1925)
Lampsilis (Ligumia) nebulosa — Frierson (1927)
Ligumia nebulosa — Haas (1969)
Villosa nebulosa — Burch (1975), Turgeon et al. (1988), Williams et al. (1993), Turgeon et al. (1998), Lydeard et al. (1999), Graf & Cummings (2007), Williams et al. (2008), Bogan (2010), Cummings & Graf (2010), ITIS (2012), Haag (2012), Williams et al. (2017)
Villosa iris — R.I. Johnson (1980)
Cambarunio nebulosus — Watters (2018), Graf & Cummings (2021), FMCS (2021), Hopper et al. (2023)

Unio radians Lea, 1857
Lea, 1857. Proc. Acad. Nat. Sci. 9: 32.
Lea, 1859. Jour. Acad. Nat. Sci. 4 [O. 7]: 201, pl. 23, fig. 84.
Type(s): HOLOTYPE USNM_85156, Othcalooga Cr., Ga.

Lampsilis (sec. Eurynia) nebulosus — Simpson (1900)
Lampsilis (Eurynia) nebulosa — Simpson (1914)
— de Gregorio (1914)
Eurynia nebulosus — Ortmann (1918)
Lampsilis (Ligumia) radians — Frierson (1927)
Ligumia radians — Haas (1969)
Villosa nebulosa — Burch (1975), Williams et al. (2008)
Cambarunio nebulosus — Watters (2018)

Unio discrepans Lea, 1860
Lea, 1860. Proc. Acad. Nat. Sci. 12: 92.
Lea, 1860. Jour. Acad. Nat. Sci. 4 [O. 8]: 340 [22], pl. 55, fig. 165.
Type(s): HOLOTYPE USNM_85267, N Alabama.

Lampsilis (sec. Eurynia) nebulosus — Simpson (1900)
Lampsilis (Eurynia) nebulosa — Simpson (1914)
Eurynia nebulosus — Ortmann (1918)
Lampsilis (Ligumia) nebulosa — Frierson (1927)
Ligumia nebulosa — Haas (1969)
Villosa iris — Parmalee & Bogan (1998), Williams et al. (2008)
Cambarunio nebulosus — Watters (2018)

Unio plancus Lea, 1860
Lea, 1860. Proc. Acad. Nat. Sci. 12: 307.
Lea, 1862. Jour. Acad. Nat. Sci. 5 [O. 8]: 81 [85], pl. 10, fig. 229.
Type(s): HOLOTYPE USNM_85345, Coosa R., Wetumpka, Ala.

Lampsilis (sec. Eurynia) plancus — Simpson (1900)
Lampsilis (Eurynia) planca — Simpson (1914)
Lampsilis (Ligumia) radians — Frierson (1927)
Ligumia radians — Haas (1969)
Villosa nebulosa — Burch (1975), Williams et al. (2008)
Cambarunio nebulosus — Watters (2018)

Unio planicostatus Lea, 1860
Lea, 1860. Proc. Acad. Nat. Sci. 12: 92.
Lea, 1860. Jour. Acad. Nat. Sci. 4 [O. 8]: 354, pl. 59, fig. 179.
Type(s): HOLOTYPE USNM_85975, Tuscumbia, Ala.

Lampsilis (sec. Eurynia) planicostatus — Simpson (1900)
Lampsilis (Eurynia) planicostata — Simpson (1914)
— de Gregorio (1914)
Eurynia nebulosus — Ortmann (1918)
Micromya nebulosa — Ortmann (1925)
Lampsilis (Ligumia) vibex-planicostata — Frierson (1927)
Ligumia vibex — Haas (1969)
Villosa nebulosa — Burch (1975)
Villosa iris — Parmalee & Bogan (1998), Williams et al. (2008)
Cambarunio nebulosus — Watters (2018)

Unio difficilis Lea, 1868
Lea, 1868. Proc. Acad. Nat. Sci. 20: 144.
Lea, 1868. Jour. Acad. Nat. Sci. 6 [O. 12]: 311 [71], pl. 49, fig. 124.
Type(s): FIGURED SYNTYPE USNM_85158, Swamp Cr., Georgia.

Lampsilis (sec. Eurynia) nebulosus — Simpson (1900)
Lampsilis (Eurynia) planca — Simpson (1914)
Lampsilis (Ligumia) radians — Frierson (1927)
Ligumia radians — Haas (1969)
Villosa nebulosa — Burch (1975), Williams et al. (2008)
Cambarunio nebulosus — Watters (2018)