Onchopristis was a genus of prehistoric cartilaginous fish that lived during the Cretaceous period, and despite looks, it is actually a sawskate, a kind of rajid (skate) ray. Spinosaurus hunted this giant sawskate occasionally, it hunted when the food was wasteful. Rugops was thought to take full advantage of the wasted food. the sawskate was gigantic, and plowed the rivers of Africa, nevertheless common droughts only brought Onchopristis to low numbers. Atlanticopristis was its equivalent in Brazil.