Here is Mei Lin on Pulau Jong with us, telling us this is the functionally extinct Tridacna maxima!Her paper is on Hydrobiologia: Can artificial substrates enriched with crustose coralline algae enhance larval settlement and recruitment in the fluted giant clam (Tridacna squamosa)? DOI 10.1007/s10750-008-9698-0 Online abstract
Congratulations Mei Lin!