Cretaceous Fossil Shark

Description: Here is a fine shark from the Cretaceous sublithographic limestone deposits of Lebanon. Since most of the skeleton of a shark is cartilage, preservation of such details as seen here are uncommon. The fins and basic body outline have also been preserved in wonderful detail. Notice the rough nature of the skin, the result of preservation of the denticles (‘little teeth”). Many cartilaginous fish have denticles in the skin; indeed, true teeth may have evolved from them in the dim past. The denticles of sharks are quite abrasive; sharkskin (shagreen) has been used by some as a substitute for sandpaper. The genus is extinct, but has a relative in the modern-day dogfish Triakis. The other partial specimen (lower right picture - 55 mm) is a bony fish known as Gaudryella.

While shark teeth are abundant in the fossils record, the preservation of an entire shark (having a cartilageneous skeleton rather than bones) is an extraordinary rarity. This fossil exemplifies the preservation often found in the Lebanese lithographic limestone where oxygen depletion and rapid sedimentation combined to inhibit decay and enable soft tissue preservation.

Also see: Class Chondrichthyes Fish Fossils