Nautiloid
Type - Cymatoceras Sakalavus
Era - Middle Cretaceous
Age - 100 million years
Location - Madagascar
Please note product may differ slightly to the image.
 
Nautiloid fossils show the shell with various chambers but of course the fleshy tentacles were too soft to fossilise, this sometimes makes it difficult to visualise what they were like when alive.
 
Their chambers filled with gas for buoyancy, and they were able to adjust their air to water ratio in each chamber through the siphuncle (tube) that ran through all of these chambers, enabling them to stay floating through the ocean.
 
They also used Jet propulsion for movement, they had a hyponone, which was a muscular, funnel-like structure used to expel water, they could use this to move backwards at faster speeds when needed (probably to escape predators)
 
Learn more on our blog post here - Living Fossils: The Ancient Beauty of Nautiloids