2.7" Cretaceous Giant Sawfish (Onchopristis) Rostral Barb
These fossils are found in a thin bed that outcrops around the edge of a large plateau near Taouz, Morocco. Local miners collect these fossils by digging tunnels into this plateau following this layer. A paper on this assemblage can be found at: Vertebrate assemblages from the early Late Cretaceous of southeasternMorocco: An overview
We know that for the modern sawfish, the rostrum is covered with electrosensitive pores that allow the sawfish to detect slight movements of prey hiding in the muddy sea floor. The rostrum also serves as a digging tool. Should suitable prey try to swim past, the normally lethargic sawfish springs from the bottom and slashes at it with its saw.
Sawfish also defend themselves with their rostrum against intruding predators such as sharks.
The bazaar looking Onchopristis were frequently torn apart by Spinosaurus when this enormous ray traveled up freshwater streams to breed and lay eggs. Onchopristis probably lived in schools. Crocodiles, Spinosaurus and other fish-eating theropods would have feasted on the 8 meter long rays.