Description: This is a very well-preserved example of a xenacanthid shark known as Xenacanthus humbergensis. While xenacanthids first appeared in the Carboniferous, the genus Xenacathus made its appearance in the Devonian, and survived until the end of the Triassic, having survived the Great Dying at the end of the Permian. It was a freshwater shark with a maximum length of about 1 meter, and was distinguished from modern sharks by the ribbon-like dorsal fin and the distinctive spine that gave the genus its name. Due to the fact that so much of a shark is only cartilage, they are usually known only from preserved teeth and spines, with a complete example such as this occasionally found. Specimens are no longer being quarried from the region, so acquisition from older collections are the only way to add a fine example such as this to your collection. There are two repaired cracks to the distal portion of the fish, and the matrix has been reinforced to prevent any further damage, which detracts but little from such a superb specimen.

Also see: Paleozoic Fish Fossils