Isognomon
(For the tree oyster mushroom, see Pleurotus ostreatus.)
| Isognomon Temporal range:   | |
|---|---|
![]()  | |
| Live Isognomon sp. under a rock in Kona District, Hawaii | |
| Scientific classification  | |
| Domain: | Eukaryota | 
| Kingdom: | Animalia | 
| Phylum: | Mollusca | 
| Class: | Bivalvia | 
| Order: | Pteriida | 
| Family: | Isognomonidae | 
| Genus: | Isognomon Lightfoot, 1786  | 
| Type species | |
| Ostrea perna Linnaeus, 1767  | |
| Species | |
| 
 See text  | |
| Synonyms | |
  | |
Isognomon is a genus of marine bivalve mollusks which is related to the pearl oysters.[1]
Isognomon is known in the fossil record from the Permian period to the Quaternary period (age range: 254.0 to 0.012 million years ago). Fossils of species within this genus have been found all over the world.[2]
Taxonomy
    
This genus is placed in the family Isognomonidae. However previous molecular phylogeny studies have shown that these tree oysters belong in the family Pteriidae.[3] [4]
Description
    
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.[5] It is because of the preference for mangroves that these are sometimes called tree oysters[6]
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:[2]
- †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
    
- Isognomon Lightfoot, 1786. Retrieved through: World Register of Marine Species on 12 March 2011.
 - Fossilworks
 - Temkin, I. (2010) Molecular phylogeny of pearl oysters and their relatives (Mollusca, Bivalvia, Pterioidea), BMC Evolutionary Biology 10:342
 - 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
 - Arthur Peter Hoblyn Oliver (2004). Guide to Seashells of the World. Firefly. p. 300. ISBN 978-1-55297-943-3.
 - Papuaweb Archived 2012-10-17 at the Wayback Machine
 
- 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.
 
