Isognomon sp., copyright Brocken Inaglory.

Belongs within: Pterioida.
Contains: Pteria.

The Pterioidea are a group of byssally-attached bivalves with unequal valves, the left valve generally being distinctly more inflated than the right (Cox et al. 1969). Members of the Pteriidae, the feather oysters, usually have a characteristic triangular projection on either side of the straight hinge-line. The Isognomonidae commonly possess the posterior wing of the shell but the anterior auricle is only rarely developed (Cox et al. 1969). The Malleidae, hammer clams, are a group of subequivalve or inequivalve bivalves with irregularly-shaped shells. They often have a distinctive T-shape with the straight hinge-line extending either side of the shell.

Characters (from Cox et al. 1969): Inequivalve, inequilateral, right valve generally less convex than left valve, markedly prosocline at least in juveniles with beaks situated well forward; ligament external, opisthodetic, variable otherwise; prismatonacreous or crossed lamellar, endostracum aragonitic, pallial line anteriorly discontinuous; characteristically byssate throughout life with byssal notch in right valve at least in juvenile stages.

<==Pterioidea [Pteriacea]
    |  i. s.: MerismopteriaJB12
    |           |--*M. macroptera (Morris 1845) [=Pterinea macroptera]E89
    |           |--M. acutifrons (Dana 1849) [=Cypricardia acutifrons]F71
    |           |--M. arcodes (Dana 1849) [=Cypricardia arcodes]F71
    |           `--M. imbricata (Dana 1899) [=Cypricardia imbricata]F71
    |    |--Pulvinites (Hypotrema) liasicus Damborenea 1987SB93
    |    `--*Foramelina exempla Hedley 1914BRW98
    |    |--PanisS98
    |    |--PhelopteriaJB12
    |    |--Aviculoperna aviculina (Deshayes 1864)SB93
    |    |--Bakevellia King 1848W77
    |    |    |--B. binneyi (Brown 1841)SB93
    |    |    |--B. (Bakevelloides) costata (Schlotheim 1820)KL04
    |    |    `--B. parva Meek & Hayden 1858W77
    |    `--Gervillia Defrance 1820C04
    |         |--G. joleaudi Schmidt 1935C04
    |         |--G. peracutaG31
    |         |--G. praecursorK79
    |         `--G. (Hoernesia) socialisM79
    |--Malleidae [Vulsellidae]BRW98
    |    |--NayadinaJB12
    |    |--Vulsella Röding 1798DK08
    |    |    |--V. angusta Deshayes 1858SB93
    |    |    |--V. laevigata Tate 1886DK08
    |    |    |--V. lingulataG20
    |    |    |--V. spongiarumBRW98
    |    |    `--V. vulsella (Linnaeus 1758) [=Mya vulsella]H09
    |    `--MalleusMG-H11
    |         |--M. albus Lamarck 1819MG-H11
    |         |--M. legumen Reeve 1858H09
    |         |--M. malleus (Linnaeus 1758) [=Ostrea malleus]H09
    |         |--M. meridianus Cotton 1930S-S90
    |         |--M. regula (Forsskål 1775)MG-H11
    |         `--M. vulgarisG20
         |  i. s.: MeleagrinellaJB12
         |           |--M. donezianaC79
         |           `--M. woodsiBRW98
         |         RhaetaviculaJB12
         |         Arcavicula cassiana (Bittner 1895)SB93
         |         ElectromaBW09
         |           |--E. alacorvi (Dillwyn 1817)BW09
         |           |--E. georgianaBRW98
         |           |--E. ovata (Quoy & Gaimard 1834)BW09
         |           `--E. zebraBRW98
         |    |  i. s.: P. imbricataT-Q84
         |    |         P. lataBRW98
         |    |         P. margaritifera (Linnaeus 1758)BW09
         |    |         P. martensiSW11
         |    |         P. radiata (Leach 1814)BD86
         |    |         P. vulgaris Linnaeus 1758R78
         |    |--P. maximaPC11
         |    `--+--P. fucata (Gould 1851)PC11, S-S90 [incl. Margaritifera carchariarum Jameson 1901S-S90, Pteria carchariarumS-S90]
         |       `--+--P. albina (Lamarck 1819)PC11, BW09
         |          `--P. maculata (Gould 1850)PC11, BW09
                 |    |--W. (Permoperna) hayamii Nakazawa & Newell 1968SB93
                 |    `--W. lateplanata (Waagen 1907)SB93
                 |    |--C. flammea Reeve 1858H09
                 |    |--C. modiolaris Lamarck 1819S-S90
                 |    `--C. picta (Gmelin 1791) [=Ostrea picta]H09
                 `--Isognomon Solander in Lightfoot 1786PC11, S98 [incl. MelinaBRW98]
                      |--*I. isognomon (Linnaeus 1758)S98 (see below for synonymy)
                      |--I. alatusT-Q84
                      |--I. bicolor (Adams 1845)IZ77
                      |--I. chemnitzianusC64
                      |--I. costellatusC64
                      |--‘Perna’ cumingii Reeve 1858 [=Melina cumingii]H09
                      |--I. ephippium [=Melina ephippium]BRW98
                      |--I. incisusC64
                      |--I. janusC64
                      |--I. legumen (Gmelin 1791)BW09
                      |--I. perna (Linnaeus 1758)BW09
                      |--I. quadrangularisEO64
                      |--I. radiatus (Anton 1839)IZ77
                      |--‘Isognoma’ rigida Lightfoot 1786K65
                      |--I. rekohuensis Crampton 1988S98
                      `--I. vitreaBRW98

*Isognomon isognomon (Linnaeus 1758)S98 [=Ostrea isognomonS98, Perna isognomumH09, Isognoma lignea Lightfoot 1786K65]

*Type species of generic name indicated


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[BRW98] Beesley, P. L., G. J. B. Ross & A. Wells (eds) 1998. Fauna of Australia vol. 5. Mollusca: The Southern Synthesis. Part A. Australian Biological Resources Study: Canberra.

[BW09] Bryce, C., & C. Whisson. 2009. The macromolluscs of Mermaid (Rowley Shoals), Scott and Seringapatam Reefs, Western Australia. Records of the Western Australian Museum Supplement 77: 177–208.

[C79] Callomon, J. H. 1979. Marine boreal Bathonian fossils from the northern North Sea and their palaeogeographical significance. Proceedings of the Geological Association 90: 163–169.

[C64] Carpenter, P. P. 1864. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Report of the British Association for the Advancement of Science 33: 517–686.

[C04] Carter, J. G. 2004. Evolutionary implications of a duplivincular ligament in the Carboniferous pinnid Pteronites (Mollusca, Bivalvia, Pteriomorphia). Journal of Paleontology 78 (1): 235–240.

Cox, L. R., N. D. Newell et al. 1969. Treatise on Invertebrate Paleontology pt N. Bivalvia vol. 1. The Geological Society of America, Inc. and The University of Kansas.

[DK08] Darragh, T. A., & G. W. Kendrick. 2008. Silicified Eocene molluscs from the Lower Murchison district, Southern Carnarvon Basin, Western Australia. Records of the Western Australian Museum 24 (3): 217–246.

[EO64] Emerson, W. K., & W. E. Old Jr. 1964. Additional records from Cocos Island. Nautilus 77 (3): 90–92.

[E89] Etheridge, R., Jr. 1889. Remarks on fossils of Permo-Carboniferous age, from north-western Australia, in the Macleay Museum. Proceedings of the Linnean Society of New South Wales, series 2, 4 (2): 199–214, pl. 17.

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1–167.

[G20] Goldfuss, G. A. 1820. Handbuch der Naturgeschichte vol. 3. Handbuch der Zoologie pt 1. Johann Leonhard Schrag: Nürnberg.

[G31] Grabau, A. W. 1931. The Permian of Mongolia: A report on the Permian fauna of the Jisu Honguer limestone of Mongolia and its relations to the Permian of other parts of the world. American Museum of Natural History: New York.

[H09] Hedley, C. 1909. The Marine Fauna of Queensland: Address by the President of Section D. Australasian Association for the Advancement of Science: Brisbane.

[IZ77] Ingham, R. E., & J. A. Zischke. 1977. Prey preferences of carnivorous intertidal snails in the Florida Keys. Veliger 20 (1): 49–51.

[JB12] Johnson, M. E., & B. G. Baarli. 2012. Development of intertidal biotas through Phanerozoic time. In: Talent, J. A. (ed.) Earth and Life: Global biodiversity, extinction intervals and biogeographic perturbations through time pp. 63–128. Springer.

[K65] Kay, E. A. 1965. The Reverend John Lightfoot, Daniel Solander, and the Portland Catalogue. Nautilus 79 (1): 10–19.

[KL04] Klug, C., & A. Lehmkuhl. 2004. Soft-tissue attachment structures and taphonomy of the Middle Triassic nautiloid Germanonautilus. Acta Palaeontologica Polonica 49 (2): 243–258.

[K79] Kummel, B. 1979. Triassic. In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A351–A389. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[MG-H11] McEnnulty, F. R., K. L. Gowlett-Holmes, A. Williams, F. Althaus, J. Fromont, G. C. B. Poore, T. D. O’Hara, L. Marsh, P. Kott, S. Slack-Smith, P. Alderslade & M. V. Kitahara. 2011. The deepwater megabenthic invertebrates on the western continental margin of Australia (100–1100 m depths): composition, distribution and novelty. Records of the Western Australian Museum Supplement 80: 1–191.

[M79] Müller, A. H. 1979. Fossilization (taphonomy). In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A2–A78. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[PC11] Plazzi, F., A. Ceregato, M. Taviani & M. Passamonti. 2011. A molecular phylogeny of bivalve mollusks: ancient radiations and divergences as revealed by mitochondrial genes. PLoS One 6 (11): e27147.

[R78] Reid, R. G. B. 1978. The systematic, adaptive and physiological significance of proteolytic enzyme distribution in bivalves. Veliger 20 (3): 260–265.

[SB93] Skelton, P. W., & M. J. Benton. 1993. Mollusca: Rostroconchia, Scaphopoda and Bivalvia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 237–263. Chapman & Hall: London.

[S-S90] Slack-Smith, S. M. 1990. The bivalves of Shark Bay, Western Australia. In: Berry, P. F., S. D. Bradshaw & B. R. Wilson (eds) Research in Shark Bay: Report of the France-Australe Bicentenary Expedition Committee pp. 129–157. Western Australian Museum.

[SW11] Smith, S. A., N. G. Wilson, F. E. Goetz, C. Feehery, S. C. S. Andrade, G. W. Rouse, G. Giribet & C. W. Dunn. 2011. Resolving the evolutionary relationships of molluscs with phylogenomic tools. Nature 480: 364–367.

[S98] Stilwell, J. D. 1998. Late Cretaceous Mollusca from the Chatham Islands, New Zealand. Alcheringa 22 (1): 29–85.

[T-Q84] Thiriot-Quiévreux, C. 1984. Les caryotypes de quelques Ostreidae et Mytilidae. Malacologia 25 (2): 465–476.

[W77] White, C. A. 1877. Report upon the invertebrate fossils collected in portions of Nevada, Utah, Colorado, New Mexico, and Arizona, by parties of the expeditions of 1871, 1872, 1873, and 1874. U.S. Geographical Surveys West of the One Hundredth Meridian 4 (1): 1–219, pls 1–21.

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