Ammonites are an extinct group of mollusks which died out at the close of the Cretaceous period ~65 million years ago. Ammonites were predatory marine cephalopods. The inside of the shell was divided into a chambered part and an unchambered part. The body of the animal occupied the unchambered part, or living chamber. The chambered portion of the shell was divided by partitions called septa. The septa of ammonites evolved very complex undulations which gave greater strength to a thin shell. The contact of these septa with the external shell is called a suture. Sutures are very distinctive and are an important aid in the classification of ammonites.
* Scientific proof may not be available to substantiate these claims.