Lyogyrus is a genus of very small freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Amnicolidae. ^[1]

Species within the genus Lyogyrus include:

• Lyogyrus bakerianus (Pilsbry, 1917)
• Lyogyrus brownii (H. F. Carpenter, 1872)
• Lyogyrus granum (Say, 1822)
• Lyogyrus latus F. G. Thompson & Hershler, 1991
• Lyogyrus pilsbryi (B. Walker, 1906)
• Lyogyrus pupoideus (A. Gould, 1840)
• Lyogyrus retromargo (F. G. Thompson, 1968)
• Lyogyrus walkeri (Pilsbry, 1898)

Synonyms

• † Lyogyrus beizhenensis Youluo, 1978 (unavailable name)
• Lyogyrus browni [sic]: synonym of Lyogyrus brownii (H. F. Carpenter, 1872) (incorrect spelling of original species name)
• † Lyogyrus cylindricus Youluo, 1978 (unavailable name)
• Lyogyrus dalli Pilsbry & Beecher, 1892: synonym of Amnicola dalli (Pilsbry & Beecher, 1892) (original combination)
• Lyogyrus greggi (Hershler, date unknown) - Rocky Mountain duskysnail:^[2] synonym of Colligyrus greggi (Pilsbry, 1935)
• Lyogyrus limosus (Say, 1817): synonym of Amnicola limosus (Say, 1817)
• Lyogyrus vanhyningi Vanatta, 1934: synonym of Floridobia vanhyningi (Vanatta, 1934) (original combination)

• Nomenclator Zoologicus info
• Gill, T. (1863). "Systematic arrangement of the mollusks of the family Viviparidae and others, inhabiting the United States". Proceedings of the Academy of Natural Sciences of Philadelphia. 15 (1): 34. Retrieved 23 January 2025.
• Thompson, F. G. & Hershler, R. (1991). "Two new hydrobiid snails (Amnicolinae) from Florida and Georgia, with a discussion of the biogegoraphy of freshwater gastropods of South Georgia streams". Malacological Review. 24: 62.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• Johnson, P. D.; Bogan, A. E.; Brown, K. M.; Burkhead, N. M.; Cordeiro, J. R.; Garner, J. T.; Hartfield, P. D.; Lepitzki, D. A. W.; Mackie, G. L.; Tarpley, T. A.; Tiemann, J. S.; Whelan, N. V.; Strong, E. E. (2013). "Conservation status of freshwater gastropods of Canada and the United States". Fisheries. 38 (6): 247–282.{{cite journal}}: CS1 maint: multiple names: authors list (link)