Belongs within: Neritimorpha.
The Platyceratidae are an Ordovician to Permian group of gastropods that are coprophagous on crinoids and cystoids, exhibiting a wide range of shell forms from turbiniform or naticiform to largely uncoiled. The outer shell layers are relatively thick and calcitic (Knight et al. 1960).
<==Platyceratidae [Cyclonemidae, Platyceratina, Platyceratoidea, Platyceridae]BR05
| i. s.: ‘Microdoma’ imbricata Mansuy 1921B79
|--Naticonema Perner 1903 [incl. Naticellina Perner 1911, Otospira Perner 1903]KC60
| `--*N. similare Perner 1903KC60
|--Ptychospirina Perner 1907 [=Ptychospira Perner 1903 nec Slavik 1869 nec Hall & Clarke 1893]KC60
| `--*P. mima (Perner 1903) [=Holopea mima, *Ptychospira mima]KC60
|--Himantonia Perner 1911KC60
| `--*H. amoena (Perner 1907) [=Nerita amoena]KC60
|--Praenatica Barrande 1907BR05 [incl. Prosigaretus Perner 1907KC60]
| |--*P. proeva (Perner 1903) [=Strophostylus gregarius proeva, Platyceras (*Praenatica) proevum]KC60
| `--P. chelotiF12
|--Platyostoma Conrad 1842BR05 (see below for synonymy)
| |--*P. ventricosa Conrad 1842BR17 (see below for synonymy)
| `--P. janthinoidesF12
|--Palaeocapulus Grabau & Shimer 1909 [Palaeocapulidae]BR05
| |--*P. lodiensis (Meek 1872) [=Platyceras lodiense]BR17
| `--P. permianus Grabau 1936W63
|--Strotostoma Fletcher 1958KC60
| |--*S. rylstonensis Fletcher 1958KC60
| `--S. inflata Fletcher 1958F71
|--Strophostylus Hall 1859BR05 [incl. Helicostylus Knight 1934KC60; Strophostylidae, Strophostylinae]
| |--*S. elegans Hall 1859BR17
| |--S. andrewsi Hall 1860 [=*Helicostylus andrewsi]KC60
| |--S. indicus (Waagen 1879) [=Platystoma indicum]G31
| `--S. nanus [=Naticopsis nana]G31
|--Rhabdocantha Fletcher 1958W63
| |--*R. alta (Dana 1849)W63 [=Pileopsis altaW63, Platyceras (Orthonychia) altumF71]
| |--R. adunca Fletcher 1958F71
| |--R. cornucapella (Etheridge 1896) [=Platyceras (Orthonychia) cornucapella]F71
| |--R. intermedia Fletcher 1958F71
| `--R. irregularis Fletcher 1958F71
|--Cyclonema Hall 1852 [Cyclonematidae, Cyclonematinae]BR05
| | i. s.: C. australis Etheridge 1890F71
| | C. lilydalensis Etheridge 1891F71
| | C. montrealense Billings 1865TTE93
| |--C. (Cyclonema) [incl. Cyclonemina Perner 1907]KC60
| | `--*C. (C.) bilix (Conrad 1842) [=Pleurotomaria bilix]KC60
| |--C. (Dyeria Ulrich in Ulrich & Scofield 1897)KC60
| | `--C. (*D.) costatum (James 1872) [=Cyrtolites costatus]KC60
| `--C. (Ploconema Perner 1903)KC60
| `--C. (*P.) protendens (Perner 1903) [=*Ploconema protendens]KC60
`--Platyceras Conrad 1840BR05 [=Acroculia Phillips 1841KC60, Acrocylia Agassiz 1846KC60, Acrocyllis Herrmannsen 1846KC60]
| i. s.: P. angulatumM87
| P. etheridgeiT10
| P. farleyensis Fletcher 1958F71
| P. nebrascense Meek 1872 [=P. nebrascensis]W77
| P. productiG31
|--P. (Platyceras) [incl. Actita Fahrenkohl 1844, Exogyroceras Meek & Worthen 1868]KC60
| `--*P. (P.) vetustum (Sowerby 1829) [=Pileopsis vetusta, *Acroculia vetusta]KC60
|--P. (Tubomphalus Perner 1903)KC60
| `--P. (*T.) crenistrium (Perner 1903) [=*Tubomphalus crenistria]KC60
`--P. (Visitator Perner 1911) (see below for synonymy)KC60
|--P. (*V.) extraneum (Perner 1911) [=*Visitator extraneus]KC60
`--P. (V.) tennesseenseKC60
Platyceras (Visitator Perner 1911) [incl. Aulopea Dunbar 1920, Cowwarrella Talent & Phillip 1956, Distemnostoma Dunbar 1920, Saffordella Dunbar 1920]KC60
Platyostoma Conrad 1842BR05 [=Diaphorostoma Fischer 1885KC60, Platycerina Miller 1889KC60, Platystoma Dalton 1882 nec Meigen 1803 nec (Fr.) Bonord. 1851 (ICBN) nec Hörnes 1855BR05; incl. Osterlina Tallant & Phillip 1956KC60; Platyostomatidae, Platystomidae]
*Platyostoma ventricosa Conrad 1842BR17 [=*Diaphorostoma ventricosumKC60, Platyceras (*Platyostoma) ventricosumKC60, *Platycerina ventricosaKC60]
*Type species of generic name indicated
References
[B79] Batten, R. L. 1979. Gastropods from Perak, Malaysia. Part 2. The trochids, patellids and neritids. American Museum Novitates 2685: 1–26.
[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.
[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.
[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.
[M87] Mitchell, J. 1887. Notes on the geology of Bowning, N.S.W. Proceedings of the Linnean Society of New South Wales, series 2, 1 (4): 1193–1204.
[T10] Taylor, T. G. 1910. The Archaeocyathinae from the Cambrian of South Australia with an account of the morphology and affinities of the whole class. Memoirs of the Royal Society of South Australia 2 (2): 55–188.
[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.
[W63] Waterhouse, J. B. 1963. Permian gastropods of New Zealand. Part 4—Platyceratacea, Anomphalacea, Neritacea, and correlations. New Zealand Journal of Geology and Geophysics 6 (5): 817–842.
[W77] White, C. A. 1877. Report upon the invertebrate fossils collected in portions of Nevada, Utah, Colorado, New Mexico, and Arizona, by parties of the expeditions of 1871, 1872, 1873, and 1874. U.S. Geographical Surveys West of the One Hundredth Meridian 4 (1): 1–219, pls 1–21.