Serrated, .69" Fossil Shark (Xenacanthus) Tooth - Texas

Xenacanthus is a genus of extinct freshwater shark that lived between the Devonian and Triassic periods. Their distinguishing features include v-shaped teeth, a ribbon-like dorsal fin, and a large spine that protruded from the back of their head. It has been speculated that the spine had venomous properties, similar to that of a stingray spine. Fossil records indicate that their maximum length was around 4 feet. Since its skeleton was largely cartilage, most fossils of this shark are isolated teeth and spines, but some locations feature soft body preservation.