Exogyra

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Exogyra
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Ostreoida
Family: Gryphaeidae
Genus: Exogyra

Exogyra are an extinct genus of bivalve mollusks, akin to oysters, from the Jurassic and Cretaceous periods. They have an exceptionally thick pair of shells, the left one of which is coiled whereas the right is flatter. They are supposed to have evolved from a Ceratostreon ancestor.[1]

[edit] References

  1. ^ Evolution of Exogyra plexa