Detailed 1.32" Onchopristis (Giant Sawfish) Rostral Barb

This is a rostral barb/tooth from the extinct, Cretaceous aged sawfish, Onchopristis numidus. There are a couple of repaired cracks in the tooth but it does not appear to be a composite.

Onchopristis, or “giant saw”, is a genus of extinct giant sawskate that lived during the Upper Cretaceous in what is now North Africa. It had a long, hard, shovel-shaped snout called a rostrum. The saw-like rostrum, lined on both sides with modified tooth-like structures with hooks and barbs called denticles. Onchopristis used its intimidating, 2-meter long rostrum to unearth crustaceans at the bottom of shallow waters like sawfish do today.





With 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 bizarre-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.


The Kem Kem Beds are famous for yielding a diverse, Late Cretaceous, vertebrate assemblage including fish, reptiles and dinosaurs such as Spinosaurus. 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 narrow tunnels by hand into this plateau following the layer.

A paper on this assemblage can be found at: Vertebrate assemblages from the early Late Cretaceous of southeastern Morocco: An overview

One of the tunnels dug into the Kem Kem beds by local miners following the productive fossil beds.
One of the tunnels dug into the Kem Kem beds by local miners following the productive fossil beds.

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DETAILS
SPECIES
Onchopristis numidus
LOCATION
Taouz, Kem Kem Basin, Morocco
FORMATION
Kem Kem Beds
SIZE
1.32" long
CATEGORY
SUB CATEGORY
ITEM
#18965
GUARANTEE
We guarantee the authenticity of all of our specimens.