Coiled and heteromorph ammonites. The heteromorph ammonite is in the background, with a planospirally coiled ammonite in the foreground. Ammonites were marine invertebrate molluscs that formed a spiral chambered shell, with the ammonite living in the newest and largest chamber. Shells ranged in width from under 1 centimetre to over 1 metre. Ammonites first appear in the fossil record around 400 million years ago and became extinct at the end of the Cretaceous period 65 million years ago. | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Stammers, Sinclair |
Taille de l’image : | 3888 px × 5184 px |
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Property Release : | Non requis |
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