11.5cm Perisphinctes Ammonite, Jurassic
This 11.5cm Perisphinctes ammonite is a species with distinctive ribbing and well defined coils. This large ammonite dates back to the Jurassic period, approx 160 million years ago. It has come from the Tulear region of Madagascar, a country that’s famous for fossils and minerals. This beautiful specimen would make a stunning addition to any fossil collection.
Ammonites have been extinct for 65 million years. They are a form of Cephalopod, a large group of marine molluscs. They first appeared in the Devonian Period, over 4oo million years ago. The soft body tissues of the ammonites, are very rarely found as fossils, it is generally the more solid shells that are preserved. As the ammonite grew larger it added new chambers to the shell. The Ammonite only lived in the largest, and most recently formed chamber. The word Ammonite, derives from from ‘Ammon’ the Greek God. Ammonites were plankton feeders, with long tentacles, and they swam upright. Altogether, around ten thousand different species. Ammonites became extinct 65 million years ago, at the same time as the dinosaurs. Although Ammonites have long been extinct, the squid and octopus that swim in our seas now, are closely related.