Belongs within: Patellogastropoda.
Scutellastra is a genus of limpets bearing rather massive shells with an opaque, non-iridescent porcellaneous interior, and having the median central radular tooth well developed (Wilson 1993).
<==Scutellastra Adams & Adams 1854 [incl. Patellanax Iredale 1924, Penepatella Iredale 1929]W93
| i. s.: S. soyaensis (Kase & Shigeta 1996) [=Patella soyaensis]NO04
|--+--S. mexicana (Broderip & Sowerby 1829)NO04
| `--+--S. exusta (Reeve 1854)NO04
| `--+--S. flexuosa (Quoy & Gaimard 1834)NO04 (see below for synonymy)
| `--S. optima (Pilsbry 1904)NO04 [=Patella (Scutellastra) flexuosa optimaW93]
`--+--+--S. barbara (Linnaeus 1758)NO04 [=Patella barbaraKC60; incl. P. plicata Born 1778KC60, *Scutellastra plicataKC60]
| `--+--S. cochlear (Born 1778)NO04
| `--+--S. longicosta (Lamarck 1819)NO04
| `--+--S. aphanes (Robson 1986)NO04
| `--S. obtecta (Krauss 1848)NO04
`--+--+--+--S. laticostata (Blainville 1825)NO04 (see below for synonymy)
| | `--S. peronii (Blainville 1825)NO04 (see below for synonymy)
| `--+--S. chapmani (Tenison-Woods 1875)NO04 (see below for synonymy)
| `--+--S. argenvillei (Krauss 1848)NO04
| `--+--S. granularis (Linnaeus 1758)NO04
| `--S. miliaris (Philippi 1848)NO04
`--+--Cymbula Adams & Adams 1854NO04, KC60
| |--+--+--*C. compressa (Linnaeus 1758)KC60, NO04 [=Patella compressaKC60]
| | | `--C. adansonii (Dunker 1853)NO04
| | `--C. miniata (Born 1778)NO04
| `--+--C. oculus (Born 1778)NO04
| `--+--C. granatina (Linnaeus 1758)NO04
| `--+--C. canescens (Gmelin 1791)NO04
| `--C. safiana (Lamarck 1819)NO04
`--Helcion deMontfort 1810NO04, KC60
| i. s.: *H. (Helcion) pectinatus (Born 1778) [=Patella pectinata]KC60
| H. discrepans De Ryckholt 1847CD53
| H. infraliasina De Ryckholt 1847CD53
| H. spengleri Finlay 1927 [=Calyptraea corrugata Forbes 1846 non Broderip 1835, H. corrugatum]F27
|--H. pectunculus (Gmelin 1791)NO04
`--+--H. concolor (Krauss 1848)NO04
`--+--H. dunkeri (Krauss 1848)NO04
`--H. (Patinastra Thiele in Troschel 1891)KC60
`--H. (*P.) pruinosus (Krauss 1848)KC60, NO04 [=Patella pruinosusKC60]
Scutellastra chapmani (Tenison-Woods 1875)NO04 [=Patella chapmaniW93, Patellanax chapmaniM54; incl. Patella alba Tenison Woods 1876W93, Patella perplexa Pilsbry 1891W93]
Scutellastra flexuosa (Quoy & Gaimard 1834)NO04 [=Patella flexuosaW93; incl. *Penepatella inquisitor Iredale 1929KC60, W93, Patella (*Penepatella) inquisitorKC60, Patella stellaeformis Reeve 1842W93]
Scutellastra laticostata (Blainville 1825)NO04 [=Patella laticostataW93, Patellanax laticostataM54; incl. Patella neglecta Gray 1826W93, Scutellastra rustica Menke 1843W93, Patella zebra Reeve 1854W93]
Scutellastra peronii (Blainville 1825)NO04 [=Patella peroniW93, Patellanax peroniiM54; incl. Scutellastra aculeata Reeve 1855W93, Patella diemenensis Philippi 1848W93, Patella hepatica Verco 1906W93, *Patellanax squamifera Reeve 1855W93, Patella tasmanica Tenison Woods 1876W93, Patella ustulata Reeve 1855W93]
*Type species of generic name indicated
References
[CD53] Chapuis, F., & G. Dewalque. 1853. Description des fossiles des terrains secondaires de la province de Luxembourg. M. Hayez: Bruxelles.
[F27] Finlay, H. J. 1927. New specific names for austral Mollusca. Transactions and Proceedings of the New Zealand Institute 57: 488–533.
[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.
[M54] Macpherson, J. H. 1954. Molluscs (sea shells and snails). In: Willis, J. M. (ed.) The Archipelago of the Recherche pp. 55–63. Australian Geographical Society: Melbourne.
[NO04] Nakano, T., & T. Ozawa. 2004. Phylogeny and historical biogeography of limpets of the order Patellogastropoda based on mitochondrial DNA sequences. Journal of Molluscan Studies 70: 31–41.
[W93] Wilson, B. 1993. Australian Marine Shells vol. 1. Prosobranch Gastropods. Part One. Odyssey Publishing: Kallaroo (Western Australia).