(For the tree oyster mushroom, see ''

Pleurotus ostreatus ''Pleurotus ostreatus'', the oyster mushroom, oyster fungus, or hiratake, is a common edible mushroom. It was first cultivated in Germany as a subsistence measure during World War I and is now grown commercially around the world for food. It is ...

''.) ''Isognomon'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

s which is related to the

pearl oyster ''Pinctada'' is a genus of saltwater oysters, marine bivalve mollusks in the family Pteriidae. These pearl oysters have a strong inner shell layer composed of nacre, also known as "mother of pearl". Pearl oysters are not closely related to ei ...

s. ''Isognomon'' is known in the fossil record from the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

period to the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...

period (age range: 254.0 to 0.012 million years ago). Fossils of species within this genus have been found all over the world.Fossilworks
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Taxonomy

This genus is placed in the family

Isognomonidae Isognomonidae is a family (biology), family of medium-sized to large saltwater clams. They are pearl oysters, Marine (ocean), marine bivalve molluscs in the superfamily PterioideaMolluscaBase eds. (2021). MolluscaBase. Isognomonidae Woodring, 192 ...

. However previous

molecular phylogeny Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies have shown that these tree oysters belong in the family

Pteriidae Pteriidae, also called the feather oysters, is a family of medium-sized to large saltwater clams. They are pearl oysters, marine bivalve molluscs in the order Pteriida. Some of the species in this family are important economically as the sou ...

Description

These oysters grow to be about 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 A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilid ...

to completely immobilize themselves to the roots of

mangrove tree A mangrove is a shrub or tree that grows in coastal saline water, saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evoluti ...

s, corals, and other substrates. It is because of the preference for mangroves that these are sometimes called tree oysters Papuaweb

Species

* '' Isognomon alatus'' (Gmelin, 1791) — Flat tree-oyster * '' Isognomon albisoror'' (Iredale, 1939) * '' Isognomon australica'' (Reeve, 1858) * '' Isognomon bicolor'' (C.B. Adams, 1845) * '' Isognomon californicus'' (Conrad, 1837) * '' Isognomon dunkeri'' (P. Fischer, 1881) * '' Isognomon ephippium'' (Linnaeus, 1758) * † '' Isognomon fortissimus'' (L. C. King, 1933) * '' Isognomon incisum'' (Conrad, 1837) * '' Isognomon isognomum'' (Linnaeus, 1758) * '' Isognomon janus'' Carpenter, 1857 * '' Isognomon legumen'' (Gmelin, 1791) * '' Isognomon nucleus'' (Lamarck, 1819) * '' Isognomon perna'' (Linnaeus, 1767) * '' Isognomon radiatus'' (Anton, 1838) — Lister's tree oyster * '' Isognomon recognitus'' (Mabille, 1895) * '' Isognomon vulselloides'' Macsotay & Campos, 2001

Extinct species

Extinct species within this genus include: * †''Isognomon gariesensis'' Kensley and Pether 1986 * †''Isognomon gaudichaudi '' d'Orbigny 1842 * †''Isognomon isognomoides'' Stahl 1824 * †''Isognomon isognomon'' Linnaeus 1758 * †''Isognomon isognomonoides'' Stahl 1824 * †''Isognomon legumen'' Gmelin 1790 * †''Isognomon maxillatus'' Lamarck 1819 * †''Isognomon nucleus'' Lamarck 1819 * †''Isognomon quadrisulcata'' Ihering 1897 * †''Isognomon valvanoi '' Rossi de Garcia and Levy 1977 * † '' Isognomon wellmani'' Crampton, 1988 ;Species brought into synonymy: * ''Isognomon acutirostris'' (Dunker, 1869): synonym of ''Isognomon nucleus'' (Lamarck, 1819) * ''Isognomon anomioides'' (Reeve, 1858): synonym of ''Isognomon australica'' (Reeve, 1858) * ''Isognomon aviculare'' (Lamarck, 1819): synonym of ''Isognomon isognomum'' (Linnaeus, 1758) * ''Isognomon brevirostre'' Link, 1807: synonym of ''Isognomon isognomum'' (Linnaeus, 1758) * ''Isognomon dentifer'' (Krauss, 1848): synonym of ''Isognomon nucleus'' (Lamarck, 1819) * ''Isognomon isognomon'' (Linnaeus, 1758): synonym of ''Isognomon isognomum'' (Linnaeus, 1758) * ''Isognomon roberti'' Koch, 1953: synonym of ''Isognomon perna'' (Linnaeus, 1767) * ''Isognomon rude'' (Reeve, 1858): synonym of ''Isognomon isognomum'' (Linnaeus, 1758) * ''Isognomon rupella'' (Dufo, 1840): synonym of ''Isognomon nucleus'' (Lamarck, 1819) * ''Isognomon sulcatum'' Lamarck: synonym of ''Isognomon perna'' (Linnaeus, 1767) * ''Isognomon vulsella'' (Lamarck, 1819): synonym of ''Isognomon legumen'' (Gmelin, 1791)

References

* Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). ''European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification''. Collection Patrimoines Naturels, 50: pp. 180–213 * Huber M. (2010) ''Compendium of bivalves''. A full-color guide to 3,300 of the world's marine bivalves. A status on Bivalvia after 250 years of research. Hackenheim: ConchBooks. 901 pp., 1 CD-ROM * Coan E.V. & Valentich-Scott P. (2012) ''Bivalve seashells of tropical West America. Marine bivalve mollusks from Baja California to northern Peru''. 2 vols, 1258 pp. Santa Barbara: Santa Barbara Museum of Natural History. {{Taxonbar, from=Q3005613 Pteriida Bivalve genera