See text Crassostrea is a genus of true oysters (family Ostreidae)[2] containing some of the most important oysters used for food.

The genus was recent split in WoRMS, following the DNA-based phylogenies of Salvi et al. (2014 and 2017).

Pacific species were moved to a new genus Magallana.

[3] The changes are not universally welcomed by oyster researchers, as C. gigas (now M. gigas) is "one of the most researched species of marine invertebrate".

[4] Extant species are:[2] Fossil species include:[5] The genome of Crassostrea gigas (now Magallana gigas) has been recently sequenced revealing an extensive set of genes that enable it to cope with environmental stresses.