Oysters (Bivalvia: Ostreidae and Gryphaeidae) recorded from Malaysia and Singapore: Ostreidae and Gryphaeidae) recorded from Malaysia and Singapore

Oysters recorded from Malaysia and Singapore are revised herein, based on six collected species with description of shell characters and other records from the literature. The collected oysters are Saccostrea cuccullata (Born, 1778), Saccostrea mordax (Gould, 1850), Crassostrea gigas (Thünberg, 1793), Planostrea pestigris (Hanley, 1846), Dendostrea folium (Linnaeus, 1758) and Hyotissa imbricata (Lamarck, 1819). Of these, Saccostrea mordax, Dendostrea folium and Hyotissa imbricata are new records. Including other species recorded in the literature, i.e.,Alectryonella plicatula, Ostrea denselamellosa, Hyotissa hyotis and Parahyotissa numisma, there are now 10 species of oysters recorded from Malaysia and Singapore. An identification key based on shell characters is included.