Found in the Atlas Mountains of Morocco, Orthoceras are an extinct Nautiloid cephalopod that lived from the Ordovician Period to the Triassic Period (500 – 200 million years ago). They thrived during the Silurian Period (about 420 million years ago) when the various species evolved into other cephalopods such as the Ammonite and Nautiloid trilacinoceras. They are also ancestors of the modern day squid and octopus and the fact that we find their fossilized remains on the border of the Sahara Desert is just one piece of evidence that what is now a desert was once a prehistoric ocean, teeming with strange and unusual life.
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 6 feet. They had 8-10 tentacles like their modern-day relatives with an advanced, for their time, nervous system, jaws 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 fed mainly on floating plankton, small trilobites and other various gastropods along the ocean floor, or while floating. They could achieve neutral buoyancy by filling up the individual chambers with either gas or fluid though the siphuncle.