Kem Kem question

[JohnBrewer]

Why are so many teeth coming out of Morocco but skull material rare making identification of teeth nigh on impossible to species level? What holotypes exist? I can’t believe it’s just down to bone preservation as bone material is found, Olof’s album for example shows 

I get that many of the Moroccan diggers are trying to earn a wage and teeth are popular with little prep work needed so a good turnover but there are professional palaeontologists out there too. 

 

@Troodon @Tidgy's Dad @LordTrilobite

[LordTrilobite]

I'm not an expert on this. But there are a few reasons why there are more teeth for sale on the market.

 

Reptiles do not grow teeth the same way we mammals do. We get our milk teeth and those are later replaced by our adult teeth. But we never grow any new ones after that. Reptiles replace their teeth their whole lives. A little bit similar to sharks in a way, though not as ridiculous in terms of number of teeth. A shark can produce around 3000 teeth in a life. I've heard somewhere that a typical reptile can produce some 1000 teeth in a lifetime. I'm not sure if that's completely accurate, but the point stands that one animal can produce an abundance of teeth while they only have a single piece or set of a bone. So naturally bones are more rare.

 

Then there's simply what sells. Teeth from ancient monster predators are scary and cool. So more people probably collect carnivore teeth than bones. So there might also be a collecting bias in favour of teeth. You see this in pricing as well. Dinosaur teeth often have very high prices. But bones can sometimes still be bought for much lower prices.

 

And teeth are the hardest part in the body of an animal. During the fossilisation process many things can degrade or get destroyed or lost completely. But teeth generally survive the longest.

[Troodon]

To add to LT's excellent response.   What we also see in the Kem Kem that is different than other faunas is that its Theropod biased with a few sauropods in that mix.  Theropods/Sauropods have very thin skull elements making fossilization much more difficult.  Couple this with a very high energy environment during fossilization skulls with teeth do not do well.  Since teeth are more durable like LT indicated that's what typically remains.

 

Let me also add than other than Tyrannosaurs, theropod skull material with teeth is very rare and not much exist in the Hell Creek/Lance Formation while we have an abundance of theropod teeth.  

[BadlandTraveller]

Sorry to piggyback on the question but has any Hadrosaur teeth/material ever been found in Kemkem?

[Troodon]

1 hour ago, BadlandTraveller said:

Sorry to piggyback on the question but has any Hadrosaur teeth/material ever been found in Kemkem?

No there no herbivores currently on record other than two types of sauropods.  The environment in the Kem Kem would not be conducive to large herding dinosaurs like Ceratopsian or Hadrosaurs

[jpc]

I would love to see the Moroccan beds first hand to compare to what I know here in the Lance and Morrison Fms.  In a week of casual digging with up to eight people in the Lance, we may find one or two rex teeth.  I imagine these Moroccans making a living at it probably work more intensely than we do, but still if the teeth are anywhere near the percentage of the, say, total haul, there must be tons of material that they are simply discarding.  

[Troodon]

16 minutes ago, jpc said:

I would love to see the Moroccan beds first hand to compare to what I know here in the Lance and Morrison Fms.  In a week of casual digging with up to eight people in the Lance, we may find one or two rex teeth.  I imagine these Moroccans making a living at it probably work more intensely than we do, but still if the teeth are anywhere near the percentage of the, say, total haul, there must be tons of material that they are simply discarding.  

Well most of the teeth and bones come from digging tunnels in the hills and its very dangerous.   Towns are dedicated to fossils so I've got to believe there are significantly lots more boots on the ground digging than what we see in the western states.

[Tidgy's Dad]

I agree with all of the above. 

Hundreds of people make a living from mining the various fossil beds in Morocco, and thousands more are employed in other ways.

http://archive.aramcoworld.com/issue/200902/morocco.s.trilobite.economy.htm

I've posted this elsewhere and it is really about the trilobites, but you get the picture, the same is happening in the Kem Kem region with the teeth. 

[Sagebrush Steve]

4 hours ago, Troodon said:

To add to LT's excellent response.   What we also see in the Kem Kem that is different than other faunas is that its Theropod biased with a few sauropods in that mix.  Theropods/Sauropods have very thin skull elements making fossilization much more difficult.  Couple this with a very high energy environment during fossilization skulls with teeth do not do well.  Since teeth are more durable like LT indicated that's what typically remains.

 

Let me also add than other than Tyrannosaurs, theropod skull material with teeth is very rare and not much exist in the Hell Creek/Lance Formation while we have an abundance of theropod teeth.  

So maybe you can answer this question that keeps popping up in my mind.  If Kem Kem is mostly Theropods with very few sauropods or other herbivores, what did the Theropods eat?  I thought the ratio of herbivores to carnivores should typically be very large in favor of herbivores.  Were the Kem Kem Theropods all cannibals?

[Troodon]

@Sagebrush Steve

The Kem Kem paleoenvironment was not what you see in the cretaceous of North America.  It was a semi-aquatic environment with no large prairies to support herding herbivores.  Their diet was primarly acquatic and a paper recently confirmed that by analyzing their bones.   If you look at the teeth of Spinosaurids and Carcharodontosaurids they are not designed eat herbivores but softer tissue animals.   

[caldigger]

2 hours ago, Troodon said:

 

  If you look at the teeth of Spinosaurids and Carcharodontosaurids they are not designed eat herbivores but softer tissue animals.   

Such as the little known Jellosaurus.  There is very little evidence of them in the fossil record due to their poor preservation.

Let's also not forget the all so famous Spinelesssaurus...poor things just couldn't move to well.

[doushantuo]

 

 

 

 

 

 

 

 

 

Langcavinmaioboudadsamankasetal.2013.UnbalancedfoodwebKemKem.pdf

(outtakes : see above)

mcgowadykfossildiversitygsadinosamoro041.pdf

[LordTrilobite]

7 hours ago, Troodon said:

@Sagebrush Steve

The Kem Kem paleoenvironment was not what you see in the cretaceous of North America.  It was a semi-aquatic environment with no large prairies to support herding herbivores.  Their diet was primarly acquatic and a paper recently confirmed that by analyzing their bones.   If you look at the teeth of Spinosaurids and Carcharodontosaurids they are not designed eat herbivores but softer tissue animals.   

I would like to point out that Carcharodontosaurus does seem to be a dinosaur eater, and it's also present in more terrestrial areas such as Niger, where ornithopods like Ouranosaurus are found. So the reason why we find so much Spinosaurid material is because they might have lived in the Kem Kem region all year round. While other predators might only occasionally have eaten fish.

[Troodon]

3 hours ago, LordTrilobite said:

I would like to point out that Carcharodontosaurus does seem to be a dinosaur eater, and it's also present in more terrestrial areas such as Niger, where ornithopods like Ouranosaurus are found. So the reason why we find so much Spinosaurid material is because they might have lived in the Kem Kem region all year round. While other predators might only occasionally have eaten fish.

Yes both Spino and Carch ate dinosaurs but I don't believe their dentition were designed as that for their primary food source.  My two cents.

[Sagebrush Steve]

11 hours ago, doushantuo said:

 

 

 

 

 

 

 

 

 

Langcavinmaioboudadsamankasetal.2013.UnbalancedfoodwebKemKem.pdf

(outtakes : see above)

mcgowadykfossildiversitygsadinosamoro041.pdf

 

Interesting information.  Figure 1 in the first paper by Lang et. al. shows that various types of fish account for about 60-70 percent of the fossil remains.  If you take the ratio of fish to Theropods you come up with about 13:1.  As mentioned elsewhere in the paper the ratio of herbivores to carnivores in the savannahs of Africa today is more like 400:1.  Given that Cretaceous fish were probably small compared to the Theropods, it doesn’t seem like a 13:1 ratio would make them a sufficient food source.  The other paper suggests there may be some bias because people only collect the rare Theropod fossils, but the Lang paper discounts that.  Looks like there is opportunity for someone (not me!) to do a Ph.D. dissertation on the subject.

[JohnBrewer]

Thanks all for your comments and papers. 

[doushantuo]

because someone mentioned hadrosaurs(their absence in the Cretaceous Tethyan paleodomain is noticable):

[doushantuo]

Sauropoda in Africa

 

 

Cenomanian paleogeography:

 

As hase been pointed out,the Kem Kem sequence is (litho)stratigraphically  anomalous:siltstones occuring both updip and downdip in a regressive facies trend(image from

Essafrouui et al :

 

 

[LordTrilobite]

8 hours ago, doushantuo said:

because someone mentioned hadrosaurs(their absence in the Cretaceous Tethyan paleodomain is noticable):

Europe actually has plenty of Hadrosaurs. In Spain and Romania most notably. There have also been a few remains in the Netherlands. Both Saurolophine and Lambeosaurine as well as Rabdodontids are all present. Though I think most of these deposits are all Maastrichtian. Many of these are smaller variants of the same families we see in far Eastern Asia and in North America. But since Iguanodontids are also present south of Morocco in Niger in the Early Cretaceous it seems odd that there is a complete lack of these types of animals in the Kem Kem beds, even if it's mostly river delta.

[doushantuo]

Edmontosaurus taphonomy

edit:I'll not retract this one.

But the relevance is tangential