Kolihapeltis chlupaci hollardi trilobite clearly showing the scimitar-shaped cephalic spines.
Cephalic spines (head spines) are spines or "horns" on the heads of animals, either for display,or sexual dimorphism. They are most commonly seen in trilobites, particularly those from Morocco, and hybodont sharks.
Sharks[]
A 3-D model of Hybodus clearly showing the cephalic spines on it's head.
In hybodont sharks, cephalic spines are thought to represent secondary sexual structures found in adult male hybodont sharks, and may have aided in the grasping of a female during copulation.
One or more spines were positioned behind each eye on the cheek area. The tip of the spine often bears a single barb.
Cephalic spines are often found in association with fin spines and teeth of the hybodontid shark Lissodus selachos from the Late Cretaceous Lance Formation of Whyoming.
References[]
- Welton, Bruce J., Ph.D. The Collector's Guide to Fossil Sharks and Rays from the Cretaceous of Texas. pp. 28.