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Gryphaeidae
The Gryphaeidae, common name the foam oysters or honeycomb oysters, are a family of marine bivalve mollusks. This family of bivalves is very well represented in the fossil record, however the number of living species is very few. 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. Subfamilies Genera and species within this family are divided into three subfamilies, Exogyrinae, Gryphaeinae and Pycnodonteinae. Both Exogyrinae and Gryphaeinae are completely extinct. Only two genera ''Hyotissa'' and '' Neopycnodonte'' in the subfamily Pycnodonteinae have extant species. 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 **Genus †'' Amphidonte'' Fisc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neopycnodonte
''Neopycnodonte'' is a genus of marine (ocean), marine bivalve molluscs belonging to the Family (biology), family Gryphaeidae. This genus is very well represented in the fossil record, however the number of living species is very few. Fossil specimens of ''Neopycnodonte'' species possibly dating as old as about 60 million years (Paleocene). Extant species have been recorded as fossils from the Miocene to the Quaternary (from 20.43 to 0.012 Ma). Description This genus includes deep-sea giant oysters with shells measuring up to 30 cm. The shells are usually brittle, inequivalve, with a left convex valve cemented to a substrate, while the right non-cemented one is flat or slightly concave. These bivalves can live for several centuries. Distribution and habitat While about 25 million years these mollusks formed large colonies near the coast, for unknown reasons they migrated to deeper waters. They usually live in the Mediterranean canyons or along the continental margins at d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
