Gryphaeidae

The Gryphaeidae, common name the foam oysters or honeycomb oysters, are a family of marine bivalve mollusks, and are a kind of true oyster. This family of bivalves is very well represented in the fossil record, however the number of living species is very few.

Gryphaeidae
Temporal range: Early Triassic to Recent [1]
An intact fossil shell of Exogyra flabellata (Owl Creek Formation, Late Cretaceous, Ripley, Mississippi), held in a human hand
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Ostreida
Superfamily: Ostreoidea
Family: Gryphaeidae
Vyalov, 1936
Genera

See text

Praeexogyra hebridica from the Frome Clay (Bathonian, Middle Jurassic) of Langton Herring, Dorset, England.
Liostrea strigilecula from the Carmel Formation (Middle Jurassic) of southwestern Utah.

All species have shells cemented to a substrate. Shells are considered brittle, inequivalve, with the left, lower (cemented) valve convex and the right (upper, non-cemented) valve flat or slightly concave.[2]

Subfamilies

Genera and species within this family are divided into three subfamilies, Exogyrinae, Gryphaeinae and Pycnodonteinae. Both Exogyrinae and Gryphaeinae are completely extinct. Only four genera Hyotissa, Parahyotissa, Pycnodonte and Neopycnodonte in the subfamily Pycnodonteinae have extant species.[3]

Genera and species

Genera and species within the family Gryphaeidae include: Family Gryphaeidae Vialov, 1936 (some genera also known as Devil's toenails)

  • Subfamily †Exogyrinae Vialov, 1936
    • Genus †Aetostreon Bayle, 1878 (disputed)
    • Genus †Amphidonte Fischer von Waldheim, 1829
    • Genus †Costagyra Vialov, 1936
    • Genus †Exogyra Say, 1820
    • Genus †Fluctogyra Vialov, 1936
    • Genus †Gryphaeostrea Conrad, 1865
    • Genus †Gyrostrea Mirkamalov, 1963
    • Genus †Nanogyra Beurlen, 1958
    • Genus †Nutogyra Vialov, 1936
    • Genus †Planospirites Lamarck, 1801
    • Genus †Vultogryphaea Vialov, 1936
  • Subfamily †Gryphaeinae Vialov, 1936
    • Genus †Africogryphaea Freneix, 1963
    • Genus †Deltoideum Rollier, 1917
    • Genus †Gryphaea Lamarck, 1801
    • Genus †Liostrea DouvillŽ, 1904
    • Genus †Pernostrea Munier-Chalmas, 1864
    • Genus †Praeexogyra Charles, 1952
  • Subfamily Pycnodonteinae Stenzel, 1959
  • Subfamily Incertae sedis
    • Genus †Parahyotissa Harry, 1985
    • Genus †Rhynchostreon

References
  1. Michael Hautmann; David Ware; Hugo Bucher (2017). "Geologically oldest oysters were epizoans on Early Triassic ammonoids". Journal of Molluscan Studies. 83 (3): 253–260. doi:10.1093/mollus/eyx018.
  2. Jocelyne Martin; Gérard Paulmier (3 February 2011). Les invertébrés marins du golfe de Gascogne à la Manche orientale. Editions Quae. p. 82. ISBN 978-2-7592-0107-5.
  3. The Paleobiology Database Gryphaeidae entry accessed on 6 February 2011


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