Kingdom: Animalia

Phylum: Chordata

Class: Osteostraci

Genus: Cephalaspis

Species: C. lyelli


Cephalaspis is a jawless fish that swam through the waters of the Devonian.‭ ‬Although jawless,‭ ‬it still had a mouth that was situated to the underside of the head,‭ ‬suggesting that it was a bottom feeder.‭ ‬Also there seems to be sensory organs on the underside of the head suggesting that it searched for buried prey items such as worms and microorganisms.‭ ‬It‭’‬s also likely that it would have sifted for organic matter that had sunk to the bottom. The armoured head of Cephalaspis is its most distinguishing feature taking up about a third of the body length and being almost as wide as it is long.‭ ‬With the mouth on the bottom of the head,‭ ‬the eyes are situated close together at the top of the skull.‭ ‬Since Cephalaspis probably did not rely on them for feeding,‭ ‬this was probably a defensive adaptation suggesting that Cephalaspis itself was prey for the predators of the time. Cephalaspis’s head shield was used as a defense against predators, since it was a slow swimmer. As well as this, it had sensory organs on the rim of its head, which were used for feeling the sand and mud, detecting any prey in the way. It lived in freshwater streams and estuaries, preferring to feed on the riverbed. In order to hunt, it would move its head from side to side, launching up sand and mud, as well as digging up any worms or crustaceans hiding in the ground. When breeding season came, Cephalaspis congregated to head for the one place they could escape the scorpions: fresh water, inland, with their convoy plowing upriver, away from the sea. They returned to the spawning grounds where they hatched, using memory. There have been a large number of remains attributed to the genus Cephalaspis,‭ ‬ranging from Europe to North America and further beyond.‭