Although a lot of this has already been posted on a number of topics, I thought consolidation it might prove useful with some additional information.
If you're planning to purchase theropod teeth from Morocco's Kem Kem Beds or already have some in your collection check this out.
Moroccan theropods are poorly understood and not a lot has been published. Very few articulated skeletons have been found and most are partial and without a skull. There is also lots of mis-information, mostly unintentional, from some dealers but especially with online auction sites. Unfortunately these are the most misidentified commercially sold dinosaur fossil around. Please post your interest here on the forum before you buy.
Background: The Kem Kem Beds also known as the ‘‘Continental Intercalaire’’ or "Continental Red Beds" are composed of three formations:
Akrabou, Aoufous and Ifezouane Formation. The latter two are the dinosaur producing sediments with the Ifezouane being the principal one. They are Cenomanian in age. The attached drawing gives a representation how they lay.
The distribution of the different groups of fossils in the Ifezouane Formation can been see in the pie chart below. Dinosaurs make up a small percentage of what is collected.
So first lets identify what is known to the best of my knowledge.
Theropods that have been described across North Africa (focus on large bodied theropods)
Theropods that have been described in Kem Kem: (family level)
Spinosaurus aegyptiacus * (Spinosauridae)
*Some paleontologist believe this species is unique to Egypt and Kem Kem material should be identified as Spinosauid indet. Lots of questions exist over Ibrahim (2014) diagnosis which validated this species.
>Carcharodontosaurus saharicus (Carcharodontosauridae)
>Deltadromeus agilis (Neovenatoridae)
>Sigilmassasaurus brevicollis (Spinosauridae)
>Sauroniops pachytholus (Carcharodontosauridae)
Theropods that have not been described from the Kem Kem but isolated teeth exist and have been reflected in scientific papers:
>Dromaeosaurid sp.? Hendrickx suggested these are actually Noasaurid indet.
Theropod teeth that are sold commercially but no scientific evidence yet to link them to the Kem Kem:
>Abelisaurus sp. (Not described from North Africa)
>Rugops sp. (Only described from Niger)
>Bahariasaurus sp. (Only described from Egypt)
>Elaphrosaurus sp. (From Jurassic of Tanzania)
So what is being sold and what are the issues?
Teeth are well understood by both collector and dealers, see photo. Issues are typically associated with restoration and compositing a larger tooth from multiple teeth. Teeth with matrix attached to them are suspect for restoration so be careful.
At least two species of Spinosaurids exits and it's currently impossible to determine if they are Spinosaurus or Sigilmassasaurus or Undescribed taxon.
Conflicting taxonomic hypotheses have been proposed. Ibrahim at al (2014) suggest that all specimens found belong to Spinosaurus aegyptiacus. Evers et al (2015) regard Spinosaurus maroccanus and Sigiilmassaurus brevicollis as belonging to the same taxon Sigiilmassaurus brevicollis which is also supported by Hendrickx et al (2016). Ever at al (2015) also described additional specimens from a second unnamed Spinosaurid. Bottom line we do not have enough specimens to eliminate ontogenetic or sexual dimorphism differences and accurately describe Spinosaurids in the Kem Kem.
So these teeth are best identified as: Spinosaurid indet.
Serrated Spinosaurid teeth..a very few examples of finely serrated teeth are popping up. Not sure we can currently say much about them other than they it's a unique morphology in the KK.
Teeth, those that are compressed and blade like, first photo. Wrinkles by the distal carina are diagnostic to this species. Mesial teeth are fat, slender and look very different (D shaped) (next three photos).
Two species currently are described Carcharodontosaurus saharicus and Sauroniops pachytholus and its impossible to differentiate teeth between these taxons. Similiar to the Spinosaurid debate one exists with these two species and if Sauroniops is valid. Similiar to Spinosaurids the big issue is having enough specimens to make a proper determination in what exists..
For these reasons best identified as : Carcharodontosaurid indet.
There are also intermediate size teeth (1 1/2") that are being sold as Deltadromeus or another theropod. I believe these could be Deltadromeus teeth but until we see scientific evidence this morphology of tooth should be identified as Theropod indet. No skull was found with the holotype or in any other discoveries so we do not know what they look like.
Teeth being sold as Dromaeosaurus are most likely misidentified, so here is what to look for. There are a few morphologies floating around but nothing as been formally described. Teeth are typically small around 1/2" (1.2cm) to over 1" (2.5cm) One morphology of these teeth are suggested by Hendrickx to be from a Noasaurid dinosaur.
Although you see many sellers using the word Raptor next to what they are offering it's unknown if there is a true raptor in the Kem Kem. Abelisaurids are not raptors
This figure identifies a study of isolated teeth by Richter (2015) and identifies two morphologies (A to D) and (E to G) as Dromaeosaurid. Mesial and distal carinae show a distinct density difference in serrations. The tip of the tooth extends past the base. On morph E/F a faint but visible constriction between crown and root is visible. The later form suggested by some paleontologists is most similiar to troodontids.
Morph variant 3 that I have in my collection but not seen in any papers
Mesial and distal carinae range show a distinct difference. A distinct twist to the mesial carina.
With new discoveries we can put a real species name to these teeth but currently they are indeterminate. These are easily identifiable but can easily be misidentified with certain morphologies of Dromaeosaurid teeth. The teeth are very compressed, the cross-section is oval at the base, the mesial side is strongly curved and the distal side is almost straight to the base of the tooth, see red lines in the photo.
These teeth could be similar to Rugops since it's an Abelisaurid but we have no scientific information to suggest that they are and should be identified as Abelisaurid indet.
There are NO theropod teeth in the Kem Kem Beds that you can currently definitively assign to a Genus, no less a Species, all should be identified to a family level..