Crassostrea
Crassostrea er ættkvísl í ostruætt sem inniheldur nokkrar helstu ostrutegundirnar notaðar sem matvæli.

Tegundir 
 Crassostrea (Sacco 1897)
 †Crassostrea alabamiensis (Lea 1833)
 Crassostrea amasa (Iredale 1939) (syn. Saccostrea scyphophilla)
 Crassostrea angulata (Lamarck 1819) - Portúgölsk ostra
 Crassostrea ariakensis (Fujita 1913)
 †Crassostrea ashleyi (Hertlein 1943) (syn. Ostrea arnoldi)
 Crassostrea belcheri (G.B. Sowerby II 1871)
 Crassostrea bilineata (Röding 1798)
 Crassostrea brasiliana (Lamarck 1819) (syn. C. brasiliensis)
 †Crassostrea cahobasensis (Pilsbry and Brown 1910)
 Crassostrea chilensis (Philippi 1845)
 Crassostrea columbiensis (Hanley 1846)
 †Crassostrea contracta (Conrad 1865)
 Crassostrea corteziensis (Hertlein 1951)
 †Crassostrea cucullaris (Lamarck 1819)
 Crassostrea cucullata (Born) (syn. Saccostrea cucullata)
 †Crassostrea cuebana (Jung 1974)
 Crassostrea dactylena (Iredale 1939)
 Crassostrea echinata (Quoy & Gaimard 1835) (syn. Saccostrea echinata)
 Crassostrea gasar (Dautzenberg 1891)
 †Crassostrea gigantissima (Finch 1824) – Giant fossil oyster
 Crassostrea gigas (Thunberg 1793) (syn. C. angulata, C. talienwhanensis) – Kyrrahafsostra
 Crassostrea glomerata (Gould 1850)
 †Crassostrea gryphoides (Schlotheim 1813)
 †Crassostrea hatcheri (Ihering 1899)
 Crassostrea hongkongensis (Lam & Morton 2003)
 Crassostrea iredalei (Sacco 1932) – Faustino
 †Crassostrea kawauchidensis (Tamura 1977)
 Crassostrea margaritacea (Lamarck 1819) (syn. Striostrea margaritacea)
 Crassostrea nippona (Seki 1934)
 Crassostrea paraibanensis (Singarajah 1980)
 †Crassostrea patagonica (d'Orbigny 1842) (syn. Ostrea ferrarisi)
 †Crassostrea raincourti (Deshayes 1858)
 Crassostrea rhizophorae (Guilding 1828)
 Crassostrea rivularis (Gould 1861)
 Crassostrea sikamea (Amemiya 1928)
 †Crassostrea titan (Conrad 1853) (syn. Ostrea prior, O. andersoni)
 †Crassostrea transitoria (Hupé 1854) (syn. Ostrea maxima)
 Crassostrea tulipa (Lamarck 1819)
 Crassostrea virginica (Gmelin 1791)

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Ostrur