This is an impressive and unusual piece. It is the rostral bone of the giant sawfish Onchopristis numidus. The rostral barbs of this enormous sawfish are relatively common in the Cretaceous quarries in the South of Morocco. However, the preservation of the rostrum is something absolutely exceptional.
This rostral bone does not have restorations or reparations. Additionally, we have 12 rostral barbs of the same species which we sell with it. They do not belong to the same specimen. However, they were extracted from the same stratigraphic level.
The teeth have been added to the rostrum in order to depict the magnanimity of this animal. The teeth are numbered in the pictures so that at all times you can mount the piece again in the same order when you receive it. All the teeth will be packaged individually with its own number.
The size of this fragment of Onchopristis rostral bone is probably only about a third of its original length.
Tooth 1: 83 mm (3.27 in) It has a series of fractures which have been restored via the filling method.
Tooth 2: 80 mm (3.15 in) It has a series of fractures which have been restored via the filling method.
Tooth 3: 63 mm (2.48 in) It has a series of fractures which have been restored via the filling method.
Tooth 4: 50 mm (1.97 in) It has a series of fractures but they have only been glued, not filled.
Tooth 5: 55 mm (2.17 in) It has a series of fractures which have been restored via the filling method. The base and the tip could belong to different teeth, but of the same size.
Tooth 6: 40 mm (1.57 in) It has a series of fractures but they have only been glued, not filled.
Tooth 7: 82 mm (3.23 in) It has a series of fractures which have been restored via the filling method. The base and the tip could belong to different teeth, but of the same size.
Tooth 8: 63 mm (2.48 in) It has a series of fractures which have been restored via the filling method. The base and the tip could belong to different teeth, but of the same size.
Tooth 9: 61 mm (2.40 in) It has a series of fractures which have been restored via the filling method. The base and the tip could belong to different teeth, but of the same size.
Tooth 10: 48 mm (1.89 in) Perfect tooth. It does not have any restoration or reparation.
Tooth 11: 49 mm (1.93 in) It has a series of fractures which have been restored via the filling method.
Tooth 12: 45 mm (1.77 in) It has a series of fractures which have been restored via the filling method. The base and the tip could belong to different teeth, but of the same size.
Despite some teeth having restorations or reparations, this is a piece of a great exhibition value. It perfectly reflects the gigantic magnitude of the jagged snout of this Cretaceous sawfish.
Illustrations by Nobu Tamura (Creative Commons)
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.
The bone rests from the sites in the south of Morocco are very scarce and valuable because of many reasons. One of them is the very same nature of the geological formation that contains them. The sediments were formed in delta and fluvial environments, where the transportation energy was relatively high. Because of this, any possibility of finding articulated rests is very rare, since the rests of dead animals where transported and deteriorated. That is why only the most robust bones or the most stable parts are usually preserved. Another reason for the lack of complete dinosaur bones in this region is the destructive methodology normally employed by the local miners in their excavations, which in the search of teeth, usually destroy many interesting bone rests.
The different Geological Formations that make up the orography of the Cretaceous in the South East of Morocco have been mostly treated in an undifferentiated and not too accurate way by collectors, by Paleontology aficionados and by fossil dealers.
Historically, fossils dealers from all around the world have identified the dinosaur pieces from this sector as belonging to the Tegana Formation. However, in a formal way, most of the last published studies refer to other nomenclature in the description of the units and formations of the Lower and Upper Cretaceous.
That's why next we include an interesting link where the Aoufous Formation and the Ifezouane Formation are described, making reference to their age, geological history, sedimentology, stratigraphy and vertebrate assemblage. It includes a brief explanation of the stratigraphic concepts that have been established formally until today in the studies of this sector of Morocco.
This way, the precise stratigraphic understanding of the origin of the rests, as well as the sedimentological analysis, enables a better paleoecologic characterization of the environments where this amazing dinosaur assemblage lived.
Link: Aoufous Formation
