by Trish Weaver
Originally posted on Research & Collections:
Greetings Blogophiles! It’s October 9th, day two of Cephalopod Awareness Days. Today is nautiloids and other lesser known cephalopods. Most of you are probably already aware of nautiloids, they show up as jewelry, as table decorations and for all you math enthusiasts, the shell of the chambered nautilus is frequently used as an example of Euclid’s golden ratio. It is good to be aware of nautiloids.
Nautiloids are a group of cephalopods belonging to the subclass Nautilidea. They have been around since the Late Cambrian, over 500 million years. The shape of their shells has varied greatly between the nautiloid orders and over geologic time. Some were slightly curved, known as cyrtocones, some had straight shells, known as orthocones. Some orthocone cephalopods even had shells that start off tightly coiled but then straighten out, making them look almost like a shepherd’s crook. Orthocone cephalopods went extinct it the Late Triassic.