(Latin: Ammonoidea) is a subclass of cephalopods (Cephalopoda).

Ammonites was extinct 65 million years ago, and existed for about 350 million years. They are found in a wide variety of species mostly from the Jurassic period. The Ammonites shells are found as fossils (although they have found trace fossils of shells with tentacles). The cephalopods shell grew with the animal, the shell was divided in sections/septa (this can be seen when they are split).  The shell grew with the living animal. The ammonoidea lived only in the last and largest chamber of the shell. Most ammonites were helical but there was ammonites with bent almost straight shells.


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