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Temporal range: Jurassic–Cretaceous
Inoceramus from the Cretaceous of South Dakota.
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Subclass: Cryptodonta
Order: Praecardioida
Family: Inoceramidae
Genus: Inoceramus
Sowerby, 1814

Inoceramus (Greek: translation "strong pot") is an extinct genus of fossil marine pteriomorphian bivalves that superficially resembled the related winged pearly oysters of the extant genus Pteria.


The taxonomy of the inoceramids is disputed, with genera such as Platyceramus sometimes classified as subgenus within Inoceramus. Also the number of valid species in this genus is disputed.

Selected species[edit]



The Western Interior Seaway in the Western Interior Sea that covered North America during the Cretaceous

Species of Inoceramus had a worldwide distribution during the Cretaceous and Jurassic periods (from 189.6 to 66.043 Ma). [1] Many examples are found in the Pierre Shale of the Western Interior Seaway in North America. Inoceramus can also be found abundantly in the Cretaceous Gault Clay that underlies London. Other locations for this fossil include Vancouver Island,[2] British Columbia, Canada; Texas, Tennessee, Kansas, California and Alaska, USA; Spain, France, and Germany.


The clam had a thick shell paved with "prisms" of calcite deposited perpendicular to the surface, which gave it a pearly luster in life.[2] Most species have prominent growth lines which appear as raised semicircles concentric to the growing edge of the shell. Paleontologists suggest that the giant size of some species was an adaptation for life in the murky bottom waters, with a correspondingly large gill area that would have allowed the animal to survive in oxygen-deficient waters.[2]


  • W. J. Kennedy, E. G. Kauffman, and H. C. Klinger. 1973. Upper Cretaceous Invertebrate Faunas from Durban, South Africa. Geological Society of South Africa Transactions 76(2):95-111
  • H. C. Kinger and W., J. Kennedy. 1980. Upper Cretaceous ammonites and inoceramids from the off-shore Alphard Group of South Africa. Annals of the South African Museum 82(7):293-320
  • Ludvigsen, Rolf & Beard, Graham. 1997. West Coast Fossils: A Guide to the Ancient Life of Vancouver Island. pg. 102-103
  • H. Gebhardt. 2001. Inoceramids, Didymotis and ammonites from the Nkalagu Formation type locakity (late Turonian to Coniacian, southern Nigeria):biostratigraphy and palaeoecologic implications). Neues Jahrbuch für Geologie und Palaeontologie, Monatshefte 2001(4):193-212
  • G. M. El Qot. 2006. Late Cretaceous macrofossils from Sinai, Egypt. Beringeria 36:3-163


  1. ^ a b Inoceramus at Fossilworks
  2. ^ a b c Ludvigsen, Rolf & Beard, Graham. 1997. West Coast Fossils: A Guide to the Ancient Life of Vancouver Island. pg. 102-103

External links[edit]