Isognomon

Isognomon Temporal range: Permian - Recent PreЄ Є O S D C P T J K Pg N
Live Isognomon sp. under a rock in Kona District, Hawaii
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Pterioida
Family:	Pteriidae
Genus:	Isognomon Lightfoot, 1786
Type species
Ostrea perna Linnaeus, 1767
species
See text.
Synonyms
Isognoma Lightfoot, 1786 (Isognoma is an alternative original spelling for Isognomon) Isognomon (Anisoperna) Iredale, 1939 Isognomon (Isognomon) Lightfoot, 1786 Isognomon (Melina) Philipsson, 1788 Isogonum Röding, 1798 Malleoperna Iredale, 1939 Melina Philipsson, 1788 Parviperna Iredale, 1939 Pedalion Dillwyn, 1817 Perna Bruguière, 1789 Pernaria Rafinesque, 1815 Sutura Megerle von Mühlfeld, 1811

(For the tree oyster mushroom, see Pleurotus ostreatus.)

See text.

Isognomon is a genus of marine bivalve mollusks which is related to the pearl oysters.

Isognomon is known in the fossil record from the Permian period to the Quaternary period (age range: 254.0 to 0.012 millions years ago). Fossils of species within this genus have been found all over the world.

This genus was formerly placed in the family Isognomonidae, however molecular phylogeny studies have shown that these tree oysters belong in the family Pteriidae.

These oysters grow to be about 4.75 inches (12.1 cm) in overall length, producing a highly irregular shell with a blue-gray and often heavily encrusted exterior but a smooth and pearly white interior. They use their byssus to completely immobilize themselves to the roots of mangrove trees, corals, and other substrates. It is because of the preference for mangroves that these are sometimes called tree oysters

Extinct species within this genus include:

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