Belongs within: Helicoidei.
The Triodopsinae are a clade of North American snails united by molecular data (Bouchet et al. 2017).
<==Triodopsinae
|--Trilobopsis Pilsbry 1939BP90
| `--T. loricataBP90
|--Vespericola Pilsbry 1939BR05 [VespericoliniBR17]
| |--*V. pilosa (Henderson 1928) [=Polygyra pilosa]BR17
| `--V. columbianaBP90
|--Cryptomastix Pilsbry 1939BP90
| |--C. germanaBP90
| |--C. mullaniBP90
| `--C. sanburniBP90
|--Allogona Pilsbry 1939BR05 [AllogoniniBR17]
| |--*A. (Allogona) profunda (Say 1821)BR17 (see below for synonymy)
| `--A. (Dysmedoma Pilsbry 1939)BP90
| `--A. (D.) ptychophoraBP90
|--Stenotrema Rafinesque 1819BR05 [Stenotrematina, StenotrematiniBR17, Stenotremini]
| | i. s.: S. abaddona Branson 1964B64
| | S. angellumH68
| | S. barbatumH68
| | S. evardsiB64
| | S. fraternumBP90
| | |--S. f. fraternumBP90
| | `--S. f. fasciatumBP90
| | S. glassi Branson 1964B64
| | S. hirsutumG59
| | S. labrosum (Bland 1862)NC01
| | S. leaiP65a
| | |--S. l. leaiP65a
| | `--S. l. aliciaeP65a
| | S. magnifumosumH64
| | S. stenotremaH68
| | S. unciferumB64
| |--S. (Stenotrema)BR17
| | |--*S. (S.) convexa Rafinesque 1819BR17
| | |--S. (S.) deceptumBP90
| | `--S. (S.) germanum [=Helix (S.) germana]C64
| `--S. (Euchemotrema Archer 1939)BP90
| `--S. (E.) leaiBP90
|--Mesodon Férussac 1821BR05 [Mesodontina, Mesodontinae, MesodontiniBR17]
| | i. s.: M. chiloweensisWM96
| | M. claususH68
| | |--M. c. claususH66
| | `--M. c. trossulus Hubricht 1966H66
| | M. clenchiB64
| | M. downieanusH65
| | M. indianorum [incl. M. binneyanus]P65b
| | M. kalmianus Hubricht 1965H65
| | M. kiowaensisW66a
| | M. laeviorH68
| | M. perigraptusHSD65
| | M. roemeriP65c
| | M. rugeliH68
| | M. rutherfordi (Russell 1929)TTE93
| | M. zaletus (Binney 1837)TMT96
| |--M. (Mesodon)BR17
| | |--*M. (M.) thyroidus (Say 1817) [=Helix thyroidus]BR17
| | |--M. (M.) columbianus [=Helix columbiana; incl. H. labiosa]C64
| | |--M. (M.) devius [=Helix devia; incl. H. baskervillei]C64
| | `--M. (M.) elevatusBP90
| |--M. (Appalachina Pilsbry 1939)BP90
| | `--M. (A.) sayanusBP90
| `--M. (Patera Albers 1850)BP90
| |--M. (P.) appressusBP90
| |--M. (P.) jonesianusBP90
| `--M. (P.) sargentianusBP90
|--Triodopsis Rafinesque 1819 [Triodopsini]BR05
| | i. s.: T. discoidea (Pilsbry 1904)NC01
| | T. fallaxG59
| | T. hopetonensisH63
| | |--T. h. hopetonensisJ65
| | `--T. h. chincoteagensisJ65
| | T. juxtidensG59
| | T. vulgataH68
| | T. vultuosuaP65a
| | |--T. v. vultuosaP65a
| | `--T. v. copeiP65a
| |--T. (Triodopsis)BR17
| | |--*T. (T.) tridentata (Férussac 1821) [=Helix tridentata]BR17
| | | |--T. t. tridentataW66b
| | | `--T. t. frisoniW66b
| | |--T. (T.) loricata [=Helix (T.) loricata; incl. H. lecontei]C64
| | |--T. (T.) mullani (Bland 1861) [=Helix mullani]C64
| | `--T. (T.) multilineataBP90
| |--T. (Neohelix Ihering 1892)BP90
| | `--T. (N.) albolabrisBP90
| `--T. (Xolotrema Rafinesque 1831)BP90
| |--T. (X.) denotataBP90
| |--T. (X.) fosteriBP90 [=Wilcoxorbis fosteriW66b]
| `--T. (X.) obstrictaBP90
`--Ashmunella Pilsbry & Cockerell 1899BR05 [Ashmunellinae, AshmunelliniBR17]
|--*A. miorhyssa (Dall 1898) [=Polygyra miorhyssa]BR17
|--A. angulataBM84
|--A. chiricahuanaBP90
|--A. kochiP15
| |--A. k. kochiW63
| `--A. k. amblaW63
|--A. lenticula Gregg 1953BM84
|--A. levetteiP15
| |--A. l. levetteiP15
| `--A. l. bifurcaP15
|--A. mearnsii (Dall 1895) [=Polygyra mearnsii]P15
|--A. proximaBM84
| |--A. p. proximaBM84
| `--A. p. albicauda Pilsbry & Ferriss 1910BM84
|--A. rhyssaBM84
| |--A. r. rhyssaBM84
| |--A. r. altissimaBM84
| `--A. r. edentataW66a
|--A. townsendiW63
|--A. variciferaBP90
`--A. walkeriP15
*Allogona (Allogona) profunda (Say 1821)BR17 [=Helix profundaBR17; incl. H. profunda var. albina non H. multilineata var. albinaW79]
*Type species of generic name indicated
References
[BM84] Babrakzai, N., & W. B. Miller. 1984. Cytogenetic study of interspecific hybrids of Ashmunella (Mollusca: Pulmonata: Polygyridae), I. A. proxima × A. lenticula F1 hybrids. Malacologia 25 (2): 413–426.
[BR05] Bouchet, P., & J.-P. Rocroi. 2005. Classification and nomenclator of gastropod families. Malacologia 47 (1–2): 1–397.
[BR17] Bouchet, P., J.-P. Rocroi, B. Hausdorf, A. Kaim, Y. Kano, A. Nützel, P. Parkhaev, M. Schrödl & E. E. Strong. 2017. Revised classification, nomenclator and typification of gastropod and monoplacophoran families. Malacologia 61 (1–2): 1–526.
[B64] Branson, B. A. 1964. Records and two new species, Stenotrema abaddona and S. glassi, from Oklahoma. Nautilus 77 (3): 100–105.
[BP90] Burch, J. B., & T. A. Pearce. 1990. Terrestrial Gastropoda. In: Dindal, D. L. (ed.) Soil Biology Guide pp. 201–309. John Wiley & Sones: New York.
[C64] Carpenter, P. P. 1864. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Report of the British Association for the Advancement of Science 33: 517–686.
[G59] Grimm, W. 1959. Land snails of Carroll County, Maryland. Nautilus 72 (4): 122–127.
[HSD65] Hermann, P. W., B. C. Strickland & D. S. Dundee. 1965. Baton Rouge greenhouse gastropods. Nautilus 78 (4): 131–133.
[H63] Hubricht, L. 1963. Triodopsis hopetonensis (Shuttleworth) in the Gulf States. Nautilus 76 (4): 152.
[H64] Hubricht, L. 1964. Stenotrema magnifumosum in the Cumberland Mountains. Nautilus 78 (2): 70.
[H65] Hubricht, L. 1965. Four new land snails from the southeastern United States. Nautilus 79 (1): 4–7.
[H66] Hubricht, L. 1966. Four new land snails. Nautilus 80 (2): 53–56.
[H68] Hubricht, L. 1968. The land snails of Mammoth Cave National Park, Kentucky. Nautilus 82 (1): 24–28.
[J65] Jacobson, M. K. 1965. New records for New York and New Jersey. Nautilus 78 (3): 83–86.
[NC01] Nekola, J. C., & B. F. Coles. 2001. Systematics and ecology of Gastrocopta (Gastrocopta) rogersensis (Gastropoda: Pupillidae), a new species of land snail from the Midwest of the United States of America. Nautilus 115 (3): 105–114.
[P15] Pilsbry, H. A. 1915. Mollusca of the southwestern states, VI: the Hacheta Grande, Florida, and Peloncillo Mountains, New Mexico. Proceedings of the Academy of Natural Sciences of Philadelphia 67 (2): 323–350, pls 5–7.
[P65a] Pratt, W. L., Jr. 1965a. Notes on land snail distribution in Texas. Nautilus 78 (4): 142–143.
[P65b] Pratt, W. L., Jr. 1965b. Carnivorous habits in Mesodon indianorum (Pilsbry). Nautilus 78 (4): 143.
[P65c] Pratt, W. L., Jr. 1965c. Sinistral Mesodon roemeri. Nautilus 78 (4): 143–144.
[TMT96] Tillier, S., M. Masselot & A. Tillier. 1996. Phylogenetic relationships of the pulmonate gastropods from rRNA sequences, and tempo and age of the stylommatophoran radiation. In: Taylor, J. D. (ed.) Origin and Evolutionary Radiation of the Mollusca pp. 267–284. Oxford University Press: Oxford.
[TTE93] Tracey, S., J. A. Todd & D. H. Erwin. 1993. Mollusca: Gastropoda. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 131–167. Chapman & Hall: London.
[WM96] Wagner, R., & E. C. Masteller. 1996. New moth flies (Diptera: Psychodidae) and a key to species from Puerto Rico. Proceedings of the Entomological Society of Washington 98 (3): 450–464.
[W79] Walker, B. 1879. Catalogue of the shell-bearing Mollusca of Michigan. Journal of Conchology 2: 325–337.
[W63] Walton, M. L. 1963. Length of life in west American land snails. Nautilus 76 (4): 127–131.
[W66a] Webb, G. R. 1966a. Land snail resistance to cold. Nautilus 80 (1): 29.
[W66b] Webb, G. R. 1966b. Copulations between Xolotrema (Wilcoxorbis) fosteri and Triodopsis tridentata frisoni. Nautilus 80 (1): 30–31.