9" Fossil Shark (Asteracanthus) Dorsal Spine - Kem Kem Beds

Fossil Shark (Asteracanthus) Dorsal Spine - Kem Kem Beds #244539

This is a large, 9" long, fossil, dorsal spine of a shark (Asteracanthus ornatissimus). It comes from the Late Cretaceous, Kem Kem Beds near Taouz, Morocco. There are two hybodontiform sharks whose spines are found in this formation with Asteracanthus being the rarer of the two.

It has several repaired cracks along its length as these spines are fairly delicate and typically are found fractured. The final 1" of its tip has been restored.

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

The Kem Kem Group is famous for yielding a diverse Late Cretaceous vertebrate assemblage, including fish, reptiles, and dinosaurs such as Spinosaurus. These fossils are found in a thin bed that outcrops around the edge of a large plateau near Taouz, Morocco. Local miners collect these fossils by digging narrow tunnels by hand into this plateau, following the layer.

A paper on this assemblage can be found at: Vertebrate assemblages from the early Late Cretaceous of southeastern Morocco: An overview

One of the tunnels dug into the Kem Kem beds by local miners following the productive fossil beds.