*Images in development
Ostreoidea, Chamoidea & Anomioidea
Lower valve not cemented to substrate but with a byssus foramen
One valve cemented to substrate
Upper valve with two scars separate or partially joined
Muscle scars smooth, upper valve often strongly sculptured ribbed with erect scales (aculeate). Gill with unreflected filaments
Heteranomia squamula
Muscle scars furrowed, Upper valve never aculeate, Gills with reflected filaments
Upper valve with radial ribs and or riblets
Upper valve smooth or with a fine cancellate but radially sinuous sculpture
Upper valve with fine wavy radial striations, muscle scars joined separated by a longitudinal ridge (alien on marine litter)
Pododesmus sp.
Both adductor muscles present, hinge with true teeth, (aliens on marine litter)
Single subcentrally situated adductor muscle scar
Shell tinged pink, commarginal frills and fluted spines
Chama sarda
Muscle scar circular-subcircular, honeycomb (vesicular) shell structure present, marginal vermicular chomata present. (deep water)
Muscle scar crescentric, chomata if present nodular (ostreiine), vesicular shell layer absent
Ovate shell with a prominent median longitudinal ridge (alien on marine litter)
Dendrostrea frons
Subcircular to ovate shells, some with plicate margin but lacking a raised longitudinal ridge
Ligulate (tongue shaped) in outline, lower valve deeply cupped with strong marginal plications, muscle scar darkly coloured, chomata absent
Crassostrea gigas
Subcircular to irregulary subcircular in outline, marginal plications weak, muscle scar not darkly coloured, ostreiine chomata present on at least the dorsal margins
With strong marginal chomata on most of the margin. Upper valve frondose rather irregular in outline. (alien on marine litter)
Ostrea equestris
Marginal chomata close to dorsal margins only, shells roughly circular, exterior scaly
