#dart shield

Dart Shield (Doryaspis nathorsti and Doryaspis arctica)-

This armored, jawless fish was discovered in Spitsbergen, Norway. They lived during the Devonian period, about 350 million years ago. Its most definitive feature is the large armored shield that covers most of its body.  The main difference between the D. nathorsti and D. arctica is that the D. nathorsti (pictured above) toothy spikes running along its snout and the front of its extended lateral spines (branchial plates). The D. arctica is smaller and has no spikes.

This prehistoric fish had a long bony protrusion near its mouth, possibly to disrupt sediment to suction up whatever was hidden underneath. The saw-like “snout” ( the pseudorostrum) was actually an extension of its “chin” plate, rather than its “nose” (the rostrum), as seen on a modern day sawfish. It had a long, flexible tail with thick scales. Its downward curving branchial plates were thought to help it maintain level swimming.