unsorted bivalves 24 Mariana Islands species bivalve sp. Abivalve sp. Bbivalve sp. Cbivalve sp. Dbivalve sp. Ebivalve sp. Fbivalve sp. Gbivalve sp. Hbivalve sp. Ibivalve sp. Jbivalve sp. Kbivalve sp. Lbivalve sp. Mbivalve sp. Nbivalve sp. Obivalve sp. Pbivalve sp. Qbivalve sp. Rbivalve sp. Sbivalve sp. Tbivalve sp. Ubivalve sp. Vbivalve sp. Wbivalve sp. X