Ammonoidea: The Spiral-Shelled Cephalopods of the Mesozoic Era

Ammonoidea is a superfamily of cephalopods that includes ammonites and their extinct relatives. They are characterized by their coiled shells, which were typically spiral in shape and had a pointed end. Ammonites first appeared during the Early Jurassic period, around 200 million years ago, and became one of the most successful and widespread marine animals of the Mesozoic Era.

Ammonoidea is a diverse group of cephalopods that includes many different families and genera. Some of the most well-known ammonites include:

* Ammonites (family Ammonitidae): These are the most common and widely distributed ammonites, known for their characteristic spiral shape and pointed end.
* Ceratitids (family Ceratitidae): These ammonites have a more complex shell structure, with multiple chambers and a distinctive "horn" or "fin" on the outer surface.
* Phylloceratids (family Phylloceratidae): These ammonites have a long, slender shape and are known for their intricate patterns and ornamentation.

Ammonoidea is an important group of fossils that provide valuable information about the evolution and diversity of cephalopods during the Mesozoic Era. They are also important for understanding the geology and paleoclimatology of the time period, as the shells of ammonites can provide information about the conditions under which they lived.