出典:Wikipedia
出典:『Wikipedia』 (2011/01/17 19:18 UTC 版)
Pycnodonte is a genus of extinct oysters, marine bivalve mollusks in the family Gryphaeidae. They are found around the world in fossil shell beds from the Valanginian (140.2 Ma) to Early Pleistocene (0.781 Ma). They are a commonly found fossil in Cretaceous shellbeds of the Navesink Formation in New Jersey.