Evolution and Systematics
Polyaspartate is a biopolymer in oysters that stops growth of shells by inhibiting growth of excess calcium carbonate.
Polyaspartate is a biopolymer produced by oysters to help mold their shells into their characteristic shape. Polyaspartate stops excess growth of calcium carbonate, the principal constituent of oyster shells. (Ashley 2002:32-33)
Learn more about this functional adaptation.
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimens with Sequences:1056
Specimens with Barcodes:1016
Species With Barcodes:53
Like scallops, true oysters have a central adductor muscle, which means the shell has a characteristic central scar marking its point of attachment. The shell tends to be irregular as a result of attaching to a substrate.
Both oviparous (egg-bearing) and larviparous (larvae-bearing) species are known within Ostreidae. Both types are hermaphrodites. However, the larviparous species show a pattern of alternating sex within each individual, whereas the oviparous species are simultaneous hermaphrodites, producing either female or male gametes according to circumstances.
Members of genus Ostrea generally live continually immersed and are quite flat, with roundish shells. They differ from most bivalves by having shells completely made up of calcite, but with internal muscle scars of aragonitic composition. They fare best in somewhat oligotrophic water. They brood their fertilized eggs for various proportions of the period from fertilization to hatching.
Members of genera Saccostrea and Crassostrea generally live in the intertidal zone, broadcast sperm and eggs into the sea, and can thrive in eutrophic water. One of the most commonly cultivated oysters is Crassostrea gigas, the Japanese oyster, which is ideally suited for cultivation in seawater ponds.
Genera and species
- Crassostrea (Sacco, 1897)
- C. angulata (Lamarck 1819) - Portuguese oyster
- C. ariakensis (Fujita, 1913) - Suminoe oyster
- C. chilensis (Philippi, 1845)
- C. columbiensis (Hanley, 1846)
- C. corteziensis (Hertlein, 1951)
- C. gasar - mangrove oyster
- C. gigas (Thunberg, 1793) - Pacific oyster
- C. glomerata (Gould, 1850) - Auckland oyster
- C. iredalei (Sacco, 1932)
- C. rhizophorae Guilding
- C. virginica (Gmelin, 1791) - eastern oyster
- Cryptostrea (Harry, 1985)
- C. permollis (G. B. Sowerby II, 1871) - sponge oyster
- Dendostrea (Swainson, 1835)
- Lopha (Roding, 1798)
- Ostrea (Linnaeus, 1758)
- Teskeyostrea (Harry, 1985)
- T. weberi (Olsson, 1951) - threaded oyster, Weber oyster
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