Rare pathological double-barbed rostral denticle of...

Scientific name: Onshopristis numidus - Sawfish rostral tooth - with genuine aberrant or pathological double-barbed denticle. Location: Taouz, South Morocco Geological Formation: Ifezouane Fm - KemKem Red Sandstone Beds Age: Upper Cretaceous, Cenomanian stage ( 96 million years) Size: 9cm REF.: #J658 DESCRIPTION: Observations: The so-called “teeth” of Onchopristis numidus are actually modified rostral denticles that were arranged laterally along its saw-like rostrum. Although these elements are relatively common in Cretaceous deposits of North Africa, particularly in the Kem Kem Beds of Morocco, specimens displaying an abnormal morphology with two distinct points or barbs are considerably rarer. The significance of this anomaly has been scientifically documented. A specific study of aberrant O. numidus denticles described a specimen possessing at least two barbs along the posterior margin and concluded that it did not necessarily represent a different species, but rather an aberrant or pathological morphology of Onchopristis numidus. The authors also noted that normal remains of this species are abundant in the Kem Kem deposits, whereas these pathological morphologies occur only occasionally. Subsequent research provides further evidence regarding their rarity and authenticity. Multi-barbed denticles have been examined using sectioning and micro-CT techniques. In one case, the specimen was found to have been manipulated by joining parts from different individuals, whereas another genuine double-barbed denticle was sectioned and showed no evidence of artificial modification. This confirms that the anomaly genuinely occurred in O. numidus, while also highlighting the importance of carefully authenticating exceptional specimens offered to collectors. About our specimen: It has some glued fractures, but after deep inspection, we concluded that this rostral tooth its very special and genuine, having double-barbed denticle showing no evidence of artificial modification. All of our fossils come with a Certificate of Authenticity. Every week, the issued Certificates of Authenticity are updated in our database verification system on our website. If you find that your certificate has not yet been updated, please contact us and we will update it immediately. Display box not included.

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