Nautiloids originated in the Cambrian period, radiating during the Ordovician. These nautiloids had straight, conical shells. Planispirally coiled Nautiloids originated in the Devonian. The shift from straight to coiled shells is thought to have been driven, at least in part, by increased mobility of coiled shells over straight ones... Read more


  • Phylum: Mollusca
  • Class: Cephalopoda

Diagnostic features

These are the features that will help you to identify fossils as nautiloids.

  • Simple suture
  • Chambers
  • Central siphuncle
  • Straight, curved or coiled shell

Stratigraphic range

Cambrian to Recent