Astraspis desiderata
Ordovician jawless fish
The very first fish to appear in the fossil record had no jaws! These fish were probably filter feeders, collecting and straining bits of food from the water by swimming with their mouths open. Tiny bony plates in their mouths created suction and crushed larger pieces of food.
Jawless fish are thought to have lived in the mud or sand at the bottom of seas, rivers, and lakes. Most early jawless fish had bony armored plates growing from the skin around their heads. These armor plates were made from aspidin, a material similar to shark’s teeth. The name Astraspis, or “star shield,” refers to the star-shaped plates on this fish’s head.
Length: 12 inches