Orthoceras : Otherwise known as “Cephalopod” meaning head and foot, which protruded out of the same shell cavity. It was a prehistoric sea creature related to the modern squid, and octopus family. These creatures grew as much as 60 feet in length. Unlike their modern day cousins which have a translucent body, The bodies of the Orthocerida (the order that the animals belonged to) were orthoconic, long and straight. Like their counterparts the ammonites, these animals had a shell that consisted of distinct chambers that were connected by a tube called a siphuncle, and separated by walls called septa. These chambers were used as ballast in which the animal controlled its balance, which was extremely useful considering they could grow up to 60 feet. They grew bigger by constantly adding more chambers to their shell.
They had 8-10 tentacles like their modern-day relatives with an advanced nervous system and eyes. They also had a hyponome, a modified foot shaped like a muscular spout or funnel which they used for locomotion, quickly thrusting out water so they could quickly dart away from predators They could achieve neutral buoyancy by filling up the individual chambers with either gas or fluid though the siphuncle.
Our Orthoceras fossils are found in the Sahara desert in Morocco, and they date back to the Devonian period (359-416) million yrs ago.
