Ammonite

Ammonoite Temporal range: Devonian – Cretaceous
Asteroceras
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Ammonoidea Zittel, 1884
Orders
Anarcestida; Clymeniida; Goniatitida; Prolecanitida; Ceratitida; Phylloceratida; Lytoceratida; Ammonitida; Ancyloceratina

Ammonites^[1] were marine cephalopod molluscs of the subclass Ammonoidea.^[2]

Their widely-known fossils show a ribbed spiral-form shell, in the end compartment of which lived the tentacled animal. These creatures lived in the seas from at least 400 to 65 million years ago. They became extinct at the K/T extinction event. Their nearest living relatives are the octopus, squid, cuttlefish and Nautilus.

Nine orders are recognised in the Ammonoidea: five in the Palaeozoic and four in the Mesozoic.

1. ↑ meaning 'ram-horned', from the Egyptian god Amun.
2. ↑ Monks, Neale and Palmer, Phil. 2002. Ammonites. London: Natural History Museum.