03160 - Top Quality 0.74 Inch Onchopristis Cretaceous Giant Sawfish Rostral Barb

Impressive tooth from the giant sawfish Onchopristis numidus, coming from the famous Cretaceous sites in the south of Morocco. This piece stands out because of its completeness and the spectacular glossy reddish color of its enamel. Not restored or glued. The contrast between the root and the enameled crown is sharp and perfect. Its root preserves the longitudinal stretch marks typical from this species. Without doubt, this is a beautiful example of rostral teeth from this amazing species of sawfish.

The teeth with strong and vivid fossilization colors such as red, orange and black come from small paleochannels composed by thin layers, in the intermediate and upper stratigraphic levels (Red Sandstone Beds), from the Aoufous and Ifezouane Formations (Kem Kem Basin, South of Morocco). The lithology of this body of sediment is characterized by the dominance of sandstones (also known as arenites) and fluvial gravel, of siliceous nature. Sometimes large concentrations of iron oxide are present, and then a small sample of that is usually present at the base of the tooth. These mineralizations are responsible for the wide range of beautiful reddish color tones, slowly drawn during millions of years via fossil-diagenetic processes. The complicated sedimentarian architecture of the layers where most large vertebrates are found makes the excavation methodology a real challenge. Sometimes the local miners have to excavate long tunnels that follow the distribution of the fossiliferous layer. 

Onchopristis is a genus of extinct giant sawfish that lived in the Lower Cretaceous to Upper Cretaceous in North Africa and New Zealand. It had an elongated snout lined laterally with barbed teeth. It is a large sawfish, known from remains throughout North America, North Africa and New Zealand. It was very large, up to 8 m (26.2 ft) long when fully grown. As with modern sawfish, Onchopristis's eyes were on top of its head, to spot predators rather than prey, and its mouth and gills were under its body. The rostrum, or snout, was around 2.5 m (8.2 ft) long, lined with barbed teeth. In the type species, O. numidus, each tooth had one barb, but in O. dunklei there were two to five barbs on each tooth, two to three in O. d. praecursor, and three to five in O. d. dunklei. The rostrum most likely would have had electrosensors to detect food in the water below them like most modern sharks and some rays. Onchopristis may have raked through the riverbed to find and then eat prey. [This last paragraph is from Wikipedia - License: Attribution-ShareAlike 3.0 Unported]

This taxon was described by Hauq (1905) and belongs to the Pristidae family. Their fossils are a good indicator of paleoenvironments related with deltas and estuaries. This type of fish constituted a big part of the diet of the great ichthyophagous coetaneous dinosaurs, such as the Spinosaurus.