Falls within: Gastropoda.
The Loxonematoidea are a superfamily of gastropods with extremely tall, narrow spires. Gastropods ranging in age from the Silurian to the present day (the deep-sea families Provannidae and Abyssochrysidae) have been assigned to the Loxonematoidea by various authors. However, the Silurian and Devonian loxonematoids of the families Loxonematidae and Palaeozygopleuridae differ in their protoconch morphology from later taxa, having a large protoconch with less than one whorl and lacking a true larval shell (Frýda & Blodgett 2004). It has therefore been suggested that the later families are not closely related to the true loxonematoids but are convergent forms. The phylogenetic position of the Loxonematoidea is similarly debatable: features of the more recent families suggest relationships with the Caenogastropoda, but the simple protoconch of the earlier ‘true’ loxonematoids may indicate a more basal position outside the caenogastropod-heterobranch-neritimorph clade (Frýda & Blodgett 2004).
The Loxonematidae are mostly relatively large gastropods known from the Middle Ordovician to Lower Carboniferous, with a median sinus in the labrum and mostly collabral ornamentation. The Palaeozygopleuridae are smaller gastropods from the Devonian and Lower Carboniferous, with the labral sinus shallow or absent (Knight et al. 1960).
<==Loxonematoidea [Stylogastropoda]
| i. s.: Spiromphalus Hayasaka 1939PE02, HS80
| Nodoloxonema Blodgett, Frýda & Racheboeuf 1999FB04
| `--*N. plusquelleci Blodgett, Frýda & Racheboeuf 1999FB04
|--Palaeozygopleuridae [Palaeozygopleurinae]BR05
| |--Pragozyga Frýda 1999FB04
| | `--*P. costata Frýda 1999FB04
| |--Medfrazyga Frýda & Blodgett 2004FB04
| | `--*M. clauticae Frýda & Blodgett 2004FB04
| |--Devonozyga Horny 1955KC60
| | `--*D. perneri Horny 1955KC60
| |--Bohemozyga Frýda & Bandel 1997FB04
| | `--B. kettneriF12
| `--Palaeozygopleura Horný 1955BR05
| | i. s.: P. chlupaci Frýda 1993FB04
| | P. hamiltoniaeMB12
| | P. venusta Thein & Nitecki 1974TTE93
| | P. wellei Thein & Nitecki 1974TTE93
| |--*P. (Palaeozygopleura) alinae (Perner 1907) [=Zygopleura alinae]FB04
| |--P. (Bojozyga Horný 1955)FB04
| |--P. (Palaeozyga Horný 1955)FB04
| | `--P. (*P.) bohemicaFB04
| `--P. (Rhenozyga Frýda 2000)FB04
| |--P. (*R.) retrostriatum (Kirchner 1915) [=Loxonema retrostriatum]FB04
| |--P. (R.) machenryi Cook 1997FB04
| `--P. (R.) reifenstuhli Frýda & Blodgett 2004FB04
`--Loxonematidae [Loxonematinae, Omospiridae, Omospirinae]BR05
|--Katoptychia Perner 1907FB04 [=Cataptychia Cossmann 1909KC60]
| `--*K. alba Perner 1907KC60
|--Stylonema Perner 1907FB04
| |--*S. potens (Perner 1907) [=Loxonema (*Stylonema) potens]KC60
| `--S. parvula Frýda & Bandel 1997BK00
|--Omospira Ulrich 1897BR17
| `--*O. laticincta Ulrich 1897BR17
|--Hypselentoma Weller 1929KC60
| `--*H. perhumerosa (Meek 1872) [=Pleurotomaria perhumerosa]KC60
|--Girvania Longstaff 1924KC60
| |--*G. excavata Longstaff 1924KC60
| `--G. leijiatunensis Xi & Yu 1990XY90
|--Spiroecus Longstaff 1924KC60
| `--*S. girvanensis Longstaff 1924KC60
|--Aulacostrepsis Perner 1907KC60
| `--*A. simplex Perner 1907KC60
|--Holopella M’Coy 1851 [Holopellidae]BR05
| |--*H. gracilior M’Coy 1851BR17
| |--H. latispiraG31
| `--H. trimorpha Waagen 1880G31
`--Loxonema Phillips 1841BR05 [incl. Rhabdostropha Donald 1905KC60]
|--*L. sinuosa (Sowerby 1839)B91 [=Terebra sinuosaKC60]
|--L. altacostatumBRW98
|--L. anglicumF71
|--L. antiquaSS16
|--L. babbindoonensis Etheridge 1907F71
|--L. lamellosumF71
|--L. multicostataG31
|--L. murrayana Salter 1859TTE93
|--L. pagoda Koken 1897TTE93
|--L. peonenseG31
|--L. quadricarinatumG31
`--L. strangulatum Lindström 1884XY90
*Type species of generic name indicated
References
[B91] Bandel, K. 1991. Über triassische “Loxonematoidea” und ihre Beziehungen zu rezenten und paläozoischen Schnecken. Paläontologische Zeitschrift 65 (3–4): 239–268.
[BK00] Bandel, K., & S. Kiel. 2000. Earliest known (Campanian) members of the Vermetidae, Provannidae and Litiopidae (Cerithioidea, Gastropoda), and a discussion of their possible relationships. Mitteilungen aus dem Geologisch-Paläontologischen Institut der Universität Hamburg 84: 209–218.
[BRW98] Beesley, P. L., G. J. B. Ross & A. Wells (eds) 1998. Fauna of Australia vol. 5. Mollusca: The Southern Synthesis. Part A. Australian Biological Resources Study: Canberra.
[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.
[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1–167.
[F12] Frýda, J. 2012. Phylogeny of Palaeozoic gastropods inferred from their ontogeny. In: Talent, J. A. (ed.) Earth and Life: Global biodiversity, extinction intervals and biogeographic perturbations through time pp. 395–435. Springer.
[FB04] Frýda, J., & R. B. Blodgett. 2004. New Emsian (Late Early Devonian) gastropods from Limestone Mountain, Medfra B-4 quadrangle, west-central Alaska (Farewell Terrane), and their paleobiogeographic affinities and evolutionary significance. Journal of Paleontology 78 (1): 111–132.
[G31] Grabau, A. W. 1931. The Permian of Mongolia: A report on the Permian fauna of the Jisu Honguer limestone of Mongolia and its relations to the Permian of other parts of the world. American Museum of Natural History: New York.
[HS80] Hoare, R. D., & M. T. Sturgeon. 1980. The Pennsylvanian pseudozygopleurid gastropod genus Gamizyga n. gen. from Ohio and West Virginia. Journal of Paleontology 54 (1): 159–187.
[KC60] Knight, J. B., L. R. Cox, A. M. Keen, R. L. Batten, E. L. Yochelson & R. Robertson. 1960. Gastropoda: systematic descriptions. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt I. Mollusca 1: Mollusca—General Features, Scaphopoda, Amphineura, Monoplacophora, Gastropoda—General Features, Archaeogastropoda and some (mainly Paleozoic) Caenogastropoda and Opisthobranchia pp. I169–I331. Geological Society of America, and University of Kansas Press.
[MB12] Mistiaen, B., D. Brice, M. K. Zapalski & C. Loones. 2012. Brachiopods and their auloporid epibionts in the Devonian of Boulonnais (France): comparison with other associations globally. In: Talent, J. A. (ed.) Earth and Life: Global biodiversity, extinction intervals and biogeographic perturbations through time pp. 159–188. Springer.
[PE02] Pan, H.-Z., & D. H. Erwin. 2002. Gastropods from the Permian of Guangxi and Yunnan Provinces, south China. Journal of Paleontology 76 (Memoir 56): 1–49.
[SS16] Süssmilch, C. A., & W. G. Stone. 1916. Geology of the Jenolan Caves district. Journal and Proceedings of the Royal Society of New South Wales 49 (3): 332–384, pls 55–56.
[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.
[XY90] Xi Y.-H., & Yu W. 1990. New materials of Silurian gastropods from SW. China. Acta Palaeontologica Sinica 29 (5): 612–622.