Bivalvia | Unionida | Unionoidea | Unionidae | Gonideinae | Rectidentini | Contradentina
13 Recent freshwater species (13 total species)
Simpson, 1900. Proc. U.S. Nat. Mus. 22: 831.
Simpson, 1914. Descr. Cat. Naiades: 1067.
(intro'd as sub-gen. of Physunio Simpson, 1900)
Type species: Unio eximius Lea, 1856 (orig. desig.) = Lens eximius
Haas, 1911. Conch. Cab. 9 (pt. 2, h. 44): pl. 18-22.
Haas, 1913. Nachr. Bl. Dtsch. Malak. Ges. 45: 35.
Haas, 1913. Conch. Cab. 9 (pt. 2, h. 48): 173.
Type species: Unio contradens Lea, 1838 (orig. desig.) = Lens contradens
Haas, 1913. Conch. Cab. 9 (pt. 2, h. 47): 140.
(intro'd as sub-gen. of Ensidens Frierson, 1911)
Type species: Unio inaequalis Rochebrune, 1882 (orig. desig.) = Lens micropterus
Haas, 1911. Conch. Cab. 9 (pt. 2, h. 44): pl. 22.
Haas, 1913. Nachr. Bl. Dtsch. Malak. Ges. 45: 36.
Haas, 1914. Conch. Cab. 9 (pt. 2, h. 49): 202.
Type species: Unio pajakomboensis Bullen, 1906 (orig. desig.) = Lens contradens
Modell, 1942. Arch. Moll. 74(5/6): 189.
Modell, 1964. Arch. Moll. 93: 114.
(intro'd as sub-gen. of Contradens Haas, 1911)
Type species: Unio verbecki Martens, 1897 (orig. desig.) = Lens contradens
‘Modell’ of Authors.
Vokes, 1980. Genera of the Bivalvia: 78.
Vaught, 1989. Class. Livinh Moll.: 122.
Millard, 2001. Class. Moll. (3): 1064.
(error for Sprickia Modell, 1942)
Type species: Unio verbecki Martens, 1897 = Lens contradens
Araujo et al., 2017. Zool. J. Linn. Soc. 179(2): 280.
(error for Contradens Haas, 1911)
Type species: Unio contradens Lea, 1838 = Lens contradens
The Taxonomic History lists the ways authors have classified the species currently assigned to Lens, since 1900.
Nodularia (s.s.) — Simpson (1900), Simpson (1914)
Physunio (s.s.) — Simpson (1900), Preston (1912), Simpson (1914), Haas (1919), Haas (1924), Haas (1952), Haas (1969)
Physunio (sec. Lens) — Simpson (1900)
Dalliella — Simpson (1900)
Trapezoideus — Simpson (1900), Preston (1912), Simpson (1914), Preston (1915), Haas (1919), ... IUCN (2012), He & Zhuang (2013), Zieritz et al. (2018), Do et al. (2018), Pfeiffer et al. (2018)
Unio — Martens (1900), Bullen (1906), Preston (1912), Simpson (1914)
Unio (Nodularia) — Dautzenberg & Fischer (1905)
Ensidens (sec. Uniandra) — Haas (1913), Thiele (1934)
Ensidens (s.s.) — Haas (1913), Haas (1969)
Contradens — Haas (1913), Haas (1914), Ortmann (1917), Haas (1924), Thiele (1934), ... Ng et al. (2020), Graf & Cummings (2021), Bieler (2021), Smith (2021), Sahidin et al. (2021)
Physunio (Lens) — Simpson (1914), Haas (1969)
Pseudodon (sec. Bineurus) — Simpson (1914)
Hyriopsis (s.s.) — Simpson (1914)
Schizocleithrum — Haas (1914)
Pseudodon (Bineurus) — Haas (1920), Haas (1969)
Ensidens (Uniandra) — Prashad (1932), Haas (1952), Haas (1969), Haas (1969)
Contradens (s.s.) — Modell (1942), Haas (1969)
Contradens (Sprickia) — Modell (1942), Haas (1969)
Physunio — van Benthem Jutting (1953), Brandt (1974), Graf & Cummings (2007), Sri-aroon et al. (2007), Bogan (2010), ... Konopleva et al. (2019), Ng et al. (2020), Graf & Cummings (2021), Wu et al. (2021), Sahidin et al. (2021)
Ensidens — F.R. Woodward (1969)
Harmandia — Brandt (1974), Graf & Cummings (2007), Bogan (2010), IUCN (2012), Zieritz et al. (2018)
Uniandra — Brandt (1974), Graf (2002), Sri-aroon et al. (2007), Hoeh et al. (2009), Bogan (2010), IUCN (2012), Bogan & Do (2014), Zieritz et al. (2015), Sahidin et al. (2021)
Contortus [sic] — Araujo et al. (2017)
Lens — Pfeiffer et al. (2021), Jeratthitikul et al. (2021), Zieritz et al. (2021), Jeratthitikul et al. (2021), Zieritz et al. (2021), ... Zhang et al. (2024), Dai et al. (2025), Dai et al. (2025), Chen et al. (2025), Chen et al. (2025)