Diademaproetus sp., a trilobite from Morocco, is similar to Cornuproetus in size and shape, but with a few morphological differences. The anterior border of Diademaproetus is prolonged forming a 'tongue' or a sub-triangular cephalic process, whereas in Cornuproetus the glabella is rounded. The genal spines are long sometimes reaching the distal part of the pygidium. Both have holochroal eyes. It dates from the Devonian.