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lone5wolf117

Carch tooth from phosphate beds ?

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lone5wolf117

Hello recently i saw this carch tooth but its was said to be form phosphate beds form whats i read chenanisaurus and a titanosaur fossils was found there but not carch whats are your opinions on this tooth would be a carch tooth ? 

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Flx

Looks more like Abelisaurid to me. However, I am not a teeth expert.

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Anomotodon

This tooth was once in my hands. I got it about a year ago with a selection of fossils from both Kem Kem Cenomanian and Khouribga Maastrichthian and assumed it is a Carch from Kem Kem (matrix that was on the tooth and preservation matches what we see in Kem Kem, and morphologically it looks Carcharodontosaurid). And I definitely remember selling it as a Carch tooth from Kem Kem, apparently it has went through at least two more collectors :megalodon_broken01:

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lone5wolf117

Recently i spoke with Nick Longrich about the tooth and he gave me some info on it wanted to share with you all.

 

A neat discovery.

 

I am pretty sure it is an abelisaur. The tooth crown is relatively short and broad, with a strongly convex anterior carina and a relatively straight posterior one. The denticles are large, with “blood grooves” extending at an angle down from them.

 

I don’t know if it is Chenanisaurus or not. It is hard to tell teeth apart beyond species level, although T. rex and Nanotyrannus are different enough that you can tell the teeth apart, especially the premaxillary teeth. I think Chenanisaurus is the best guess. But it is entirely possible that there is more than one abelisaur in the fauna, too.

 

Is it definitely from the phosphates? The teeth do turn up from time to time but they are very rare. There are a lot more teeth coming from Kem Kem. The matrix is distinct. The matrix from Kem Kem is mostly made of quartz sand, and the matrix from the phosphates is mostly phosphatic- small pieces of bone, coprolites, etc. It will look very different under a microscope. The tooth here is probably not from Sidi Daoui based on the color but light colored teeth and matrix can be found at Sidi Chennane about 20 km away.

 

• If you have samples of both Kem Kem and phosphate to compare against, you should have no problem telling the difference. Kem Kem is mostly quartz sand- little transparent, rounded, glassy grains, sometimes with finer muds and clays, usually cemented by calcium carbonate. The Couche III phosphate sands are mostly tiny fragments of bone- less transparent, generally more angular.

 

• There might also be a difference in the glues used on the specimen. If it’s from Kem Kem, it will almost certainly be stabilized using cyanoacrylate (Superglue / Krazy Glue). If you heat it, e.g. with a lighter, it will emit a harsh superglue smell. It will turn very gummy if soaked in acetone. They use tons of superglue in the Kem Kem and almost nothing else.

 

If it’s from the phosphates, it will almost certainly be stabilized using PVA (white glue). It will soften and peel off with a little bit of water. They use tons of PVA in the phosphates and almost nothing else.

 

• The tooth crown also has a distinct asymmetry in basal view in abelisaurs. The anterolateral surface of the crown is highly convex, giving the tooth a shape like an airfoil in basal view.

 

• The tooth seems to be a shed tooth. This might be more consistent with Kem Kem? Kem Kem is almost exclusively (>90% or more) shed teeth and you rarely find teeth with roots. However in the phosphates the dinosaur teeth often have roots. This is because the teeth in the phosphates are falling out of drifting carcasses, not being shed by living animals.

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Haravex

Did you end up obtaining this tooth? would be great to hear the follow up, along with a better picture of the matrix towards the base of the crown.

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lone5wolf117

Yes i did unfonately its turn out to be a tooth form kem kem beds compared to the mosaurus tooth 

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Aleksandr

Teeth from phosphate beds will be more radioactive then from Kem Kem Basin  0.3 Mzvt or higher ,but  how to check it without opportunity to get it in hand ? more probably -from Kem Kem 

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