Cephalaspis

Fossil of Cephalaspis in Aquazoo - Löbbecke Museum in Dusseldorf

• Europe
• North America

Cephalaspis was a jawless fish from the Lower Devonian, who belonged to the group of Osteostraci.

Features

He had a large, bony head shield and a lightly armored abdomen. On top of the head shield are very close together, the two eye holes, a further opening between the eyes may be housed another light- sensitive organ. A little before that, on the center line there was the keyhole-shaped nose -pituitary- opening. In depressions of the cephalic shield, a teardrop-shaped behind the nose -pituitary- opening and two curved at the edge of the cephalic shield, located scaly fields that could also serve the sensory perception were. Maybe they responded to pressure fluctuations in the water analog of the lateral line of fish today or could perceive electric fields. In arc- shaped depressions at the posterior margin of the head shield, there were two pectoral fins and outside each an acute, rear facing sting. On the underside of the head shield was located in front the mouth, behind a broad, scaly surface. The nine to ten gills were on the side.

Inside the head shield the Swedish paleontologist Erik Stenisö could identify the brain, nerves, eyes, the inner ear to the vestibular system and parts of the digestive system. The brain was, as today's fish, from the medulla, pons, and telencephalon.

Way of life

Fossils of Cephalaspis were found in freshwater deposits and sediments of river deltas and coastal lakes. The fish lived obviously on the seabed and subsisted, the semi-circular head moving to and fro, from detritus. The strong abdomen suggests that Cephalaspis could travel even longer distances in open water. Buoyancy generated by the shape of the head shield and the pectoral fins.