A great temple to the god Amon was built at Karnak in Upper Egypt around c. 1785. It is from Amon that we get his cephalopod namesake, the ammonites and also the name origin for the compound ammonia or NH3.
Ammonites were a group of hugely successful aquatic molluscs that looked like the still extant Nautilus, a coiled shellfish that lives off the southern coast of Asia. While the Nautilus lived on, ammonites graced our waters from around 400 million years ago until the end of the Cretaceous, 65 million years.
Varying in size from millimeters to meters across, these elegant marine dwellers are prized as both works of art and index fossils helping us better understand and date strata. In the photo above, my cousin and budding paleontologist Sivert, holds an ammonite from the Paris Basin.
Cousins in the Class Cephalopoda, meaning "head-footed," ammonites are closely related to modern squid, cuttlefish and octopus with complex eye structures and advanced swimming abilites. They used these evolutionary benefits to their advantage, making them successful marine predators cruising our ancient oceans expertly capturing prey with their tentacles.
Picture a hungry fellow at a smorgasborg. Now add water.