Unio discus Lea, 1838
Lea, 1836. Synopsis Fam. Naiades: addenda. [nomen nudum]
Lea, 1838. Trans. Amer. Phil. Soc. 6 [O. 2]: 74, pl. 18, fig. 57.
Type(s): HOLOTYPE USNM_85341, Found in sand ballast, Phila, Pa [Mexico].

Unio (sec. Elliptio) discus — Simpson (1900), Simpson (1914)
Unio (Lampsilis) discus — Martens (1900)
Lampsilis discus — Pilsbry (1910)
Lampsilis (Disconaias) discus — Frierson (1927), Haas (1929), Haas (1940), Haas (1969), Haas (1969)
Lampsilis (sec. Disconaias) discus — Thiele (1934)
Disconaias disca — R.I. Johnson (1998), Contreras-Arquieta (2000), Graf & Cummings (2007), Bogan (2010), Graf & Cummings (2021)
Disconaias discus — Czaja et al. (2023)

Unio mexicanus Sowerby, 1867
Sowerby, 1867. Conch. Icon. 16: pl. 55, sp. 281.
(homonym of Unio mexicanus Philippi, 1847)
Type(s): HOLOTYPE (MONOTYPY) BMNH_79-2-26-249, Mexico.

Unio (sec. Elliptio) discus — Simpson (1900), Simpson (1914)
Unio (Lampsilis) discus var. connectens — Martens (1900)
Lampsilis (Disconaias) panucoensis [sic] — Frierson (1927)
Lampsilis (Disconaias) panacoensis — Haas (1969)
Disconaias disca — R.I. Johnson (1998)

Unio lapidosus Kobelt, 1893
‘Villa in sched.’ Kobelt, 1893. Nachr. Bl. Dtsch. Malak. Ges. 25: 151.
‘Villa in sched.’ Kobelt, 1893. Icon. Land- und Süssw.-Moll. 6: 90, pl. 176, fig. 1120.
Type(s): FIGURED SYNTYPE ZMB_17236, Nordmexiko.

Unio (sec. Lapidosus) lapidosus — Simpson (1900)
Unio (Lampsilis) discus var. panucoensis [sic] — Martens (1900)
Lampsilis discus — Pilsbry (1910)
Unio (sec. Elliptio) discus — Simpson (1914)
Lampsilis (Disconaias) panucoensis [sic] — Frierson (1927)
Lampsilis (Disconaias) discus — Haas (1940)
Lampsilis (Disconaias) panacoensis — Haas (1969)
Disconaias disca — R.I. Johnson (1998)

Unio (Lampsilis) discus var. connectens Martens, 1900
‘von dem Busch’ Küster, 1861. Conchyl. Cab. 9(2): 242, pl. 81, fig. 1 [as ‘Unio panacoensis’].
Sowerby, 1867. Conch. Icon. 16: pl. 55, sp. 281 [as ‘Unio mexicanus’].
Martens, 1900. Biol. Centr.-Amer., Moll.: 510.
(intro'd as intra-sp. of Unio discus Lea, 1838)

Unio (Lampsilis) discus var. connectens — Martens (1900)
Lampsilis discus — Pilsbry (1910)
Unio (sec. Elliptio) discus — Simpson (1914)
Lampsilis (Disconaias) panucoensis [sic] — Frierson (1927)
Lampsilis (Disconaias) panacoensis — Haas (1969)
Disconaias disca — R.I. Johnson (1998)

Unio panacoensis Küster, 1861
‘von dem Busch’ Küster, 1861. Conchyl. Cab. 9(2): 242, pl. 81, fig. 1.
(misidentified reference to Unio panacoensis Philippi, 1843)

Unio (Lampsilis) discus var. connectens — Martens (1900)