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BELEMNITE FOSSILS FOR SALE
What Is A Belemnite?
Belemnitida is an extinct order of cephalopod. Like modern cuttlefish, they had an internal structure that provided shape and buoyancy. They had squid-like tentacles, but with hooks on their them instead of suction cups. Belemnites are the state fossil of Delaware.
Artist's reconstruction of a belemnite (Youngibelus). Image by Nobu Tamura, Creative Commons License
When Did Belemnites Live?
Belemnites first appear in the fossil record at the end of the Late Triassic Period about 234 million years ago, and disappeared about the same time as the dinosaurs, about 66 million years ago.
How Big Were Belemnites?
Because the only part of most belemnites that survives is the solid end of the shell, called the guard, total size is speculative. The largest guards found belong to Megateuthis elliptica and have reached 24-28 inches (60-70 cm) long. This suggests that the total length of the animal could have been as much as much as 20 feet long! The shortest guard is from the genus Neohibolites, measuring a tiny 1.2 inches (3 cm) in comparison.
Where Did Belemnites Live?
Belemnites were marine organisms occupying most of the same ocean environments that modern cuttlefish and squid occupy today. Some were quite fast and mobile, and probably occupied the open ocean much the same as modern squid. Others were probably more sluggish and kept to shallower areas.
What Did Belemnites Eat?
Belemnites were carnivores and probably ate any animal they could safely subdue. There is some evidence that some species of Belemnitida traveled in large schools and swarmed prey: this would be most likely in medium to larger species. Smaller and slower moving species would have likely relied on crabs and other crustaceans as solitary hunters, much the same as modern cuttlefish.
How Did Belemnites Move?
Belemnites had two ways of moving through the water. If they were moving slowly or just making small movements, they could move by oscillating the fins near the top of their mantles, similar to modern squids. If they needed to move rapidly, they had the capacity to move by pushing a jet of water out their syphons, just as squid and cuttlefish today.
What Are Belemnites' Closest Living Relatives?
Belemnites were most closely related to modern cuttlefish. They probably looked a lot like squid, but contain rostrums similar to those of cuttlefishes' internal shells.
What Part Of The Belemnite Is Fossilized?
The most common parts of belemnites in the fossil record are guards and tentacle hooks. This guard is the solid end of the animals' rostrum (inner shell). The hollow end of the rostrum is often destroyed before it can be fossilized. Most soft tissue does not survive fossilization, but there are a few instances where the impression of the soft tissue around the rostrum is preserved. In a few specimens, a structure that appeared to be an ink sac has been found.
Very rare belemnite fossil from the Posidonia Shale of Germany with soft-body preservation. On display at the Museum am Löwentor, Stuttgart, Germany. Creative Commons License