Magallana belcheri (Sowerby II, 1871)

Magallana belcheri (Sowerby II, 1871) View in CoL

( Fig. 4D–F)

Ostrea belcheri Sowerby II, 1871 (in 1870–1871): pl. 7, fig. 11 ( type locality: “ Eastern Seas ?”).

Ostrea siamensis Mörch, 1853: 62 ( type locality: “Singapuhra”)— nomen nudum.

Habitat. Not recorded in the wild in the upper gulf but included here for completeness.

Material examined. Site 2, Samaesan seafood market.

Published Gulf of Thailand records. Crassostrea belcheri (Sowerby II, 1871) : Chaitiamwong et al. (1971); Aungtonya et al. (1999); Yoosukh & Duangdee (1999); Day et al. (2000); Klinbunga et al. (2000, 2001, 2002, 2003, 2005); Yoosukh (2000); Bussarawit & Simonsen (2006a); ONEP (2007); Nabhitabhata (2009); Bussarawit & Cedhagen (2010; 2012); Phuwan et al. (2018); Trivej & Kesjinda (2018); Ninwichian et al. (2021).

Geographic range. Native to Southeast Asia, with sequenced records from Pakistan, Myanmar, India, Thailand, Malaysia, Singapore, Vietnam, China, and Indonesia ( Willan et al., 2021).

Remarks. This is an important aquaculture species on both sides of the Gulf of Thailand, particularly on the eastern side ( Bussarawit & Cedhagen, 2010; Trivej & Kesjinda, 2018). Three specimens purchased in the Samaesan seafood market were field identified as Crassostrea sp. ( Table 2). M. belcheri is known as the white scar oyster because its white adductor muscle scar differentiates it from M. bilineata , the black scar oyster with its black adductor muscle scar (see below).