Скачать или смотреть The Cretaceous Ammonite, Oxtropidoceras sp. from Tarrant County, Texas

Ammonites have intrigued us for thousands of years, inspiring dozens of stories, legends and myths. The name comes from its appearance: it resembles a ram’s horn. In Egyptian mythology, the God Ammon looked like a man with horns like a ram. The ancient fossil was considered Ammon’s stone, thus inheriting the name, ammonite.

Ammonites belong to the class of animals called mollusks. More specifically they are cephalopods. and first appeared in the lower Devonian Period. It is thought by some that they evolved from the older nautiloids. The cephalopods were an abundant and diverse group during the Paleozoic Era.

This Oxtropidoceras sp. ammonite is from Cretaceous deposits (103 - 105 mya) of the Goodland Formation of Tarrant County, Texas, USA and is a lovely example of the subclass Ammonoidea. Give the size of this one, at 7 inches, it is probably a female or macroconch of the species.

Cephalopods are present in today's oceans as squid, octopus, cuttlefish, and nautiloids. While they are still a diverse group with about 800 species, it is estimated that there are about 17,000 extinct species. Their hard shells were easily fossilized and so we have an abundant supply of these fossils to learn from.