5.1" Hybodus Shark Dorsal Spine - Cretaceous

Hybodus Shark Dorsal Spine - Cretaceous #49543

This

A complete fossil of Hybodus from Germany showing placement of spine. Image under GNU Free Documentation License

is a nice dorsal spine of the extinct Cretaceous aged shark Hybodus. These large spines helped to support the dorsal fins of the shark.

Hybodus was a small shark that grew up to 2 meters in length and was likely an opportunistic predator. It had a streamlined shape ideal for hunting down fast prey and two different types of teeth: sharp cutting teeth for catching prey and flatter grinding teeth for crushing. This combination may have been the key to Hybodus' success.

A paper on Hybodus spines can be found below.

Growth And Form of Finspines In Hybodont Sharks

A complete fossil of Hybodus from Germany showing placement of spine. Image under GNU Free Documentation License

This specimen contains 3 cracks, one through the middle, along with 2 hard to notice repairs along the portion proximal to the base of the spine.