Description
Ammonite Lytoceras 13cm wide
The ammonite Lytoceras is distinguishable by its large horn shape giving it a very distinctive appearance. Their growth pattern is different from other species of ammonite. They are characterised by whorls that are exposed as opposed to enveloped. It is a specimen found in Madagascar, which is an important location for fossils. This fossilised lytoceras ammonite is from the Cretaceous period. This means they are 120 million years old.
Ammonites have been extinct for 65 million years and are a form of Cephalopod, a group of marine molluscs. These first appeared in the Devonian Period, over 4oo million years ago. Generally only the outer shells of these creatures fossilise, the soft interior body tissues of the ammonites being too delicate. As the ammonite grew larger it added new chambers, with the creature itself only living in the largest, newest chamber. The actual name Ammonite, derives from from ‘Ammon’ the Greek God. Ammonites were plankton feeders, they had long tentacles, and they also swam upright. Altogether, there were in the region of ten thousand different species. The largest species were up to a metre across, whereas the smallest were only a millimetre. Ammonites became extinct 65 million years ago. The coleoids, squid, cuttlefish and also the octopus that swim in our seas now however, are closely related.
