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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, ammonites are prized as both works of art and index fossils helping us date rock. The ammonites were kissing cousins in the Class Cephalopoda, meaning "head-footed," closely related to modern squid, cuttlefish and octopus. Cephalopods have a complex eye structure and swim rapidly. Ammonites used these evolutionary benefits to their advantage, making them successful marine predators.
Ammonites cruised our ancient oceans expertly capturing prey with their tentacles. Picture a hungry fellow at a smorgasborg. Now add water.
Furthermore, the name of the gas ammonia derives from a similar source.
However, the biblical Ammonites derived their name independently, and name of the capital city of Jordan, Amman, derives from this source. However, this is not a continuous thread: as the linked article says:
(The Ghassanids were an Arabian Christian tribe who migrated to the region some centuries before the rise of Islam. It may be that the original name was preserved in the culture of these desert Arabs, who wouldn't go along with some name imposed by a Greco-Egyptian emperor. Things like this are a minefield for those studying the evolution of language.)