Tremataspis Schmidti
Anaspid
Upper Silurian
Rootsikula Formation
Island of Oesel, Estonia

34mm headshield with 103mm matrix.

Tremataspis is a genus of armored jawless fish of the Subclass Osteostraci.  This group bore one body shield with holes for the mouth, eyes and other sensory organs.  Compared with its relatives, the shield was unusually elongated, covering the whole front of the body, and was more rounded in shape.   Because it consisted of one solid piece, it probably did not grow during the animal’s adult life and might not have been present in juveniles.

It has been proposed that Tremataspis was a burrower, searching for food and hiding from predators in the seafloor.