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Question about rooted dinosaur teeth


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PetrosTrilobite

A simple question. How a dinosaur lost a tooth with the root? Ok, easy for a predator, but herbivores like Triceratops or hadrosaurs how lost rooted teeth?

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They usually come from skulls that have broken apart after the dinosaur has died.  So most are post mortem finds that have washed away or separated from the skull / skeleton.  Remember skulls are made of multiple elements and those that contain the teeth include the premaxilla, maxilla and dentary which deteriorate over time exposing the teeth.   After the dinosaur dies and the body tissue deteriorate there is nothing to hold the functional teeth so they can easily come out.

In Herbivores like Triceratops or Edmontosaurus a sheath holds the teeth in place.  When it deteriorates the teeth can fall out.

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yeah, what he said.

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That's interesting. Does it mean shed teeth are unrooted while rooted ones are post-mortem? Does it concern ichthyo/plesiosaurs too?

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Yes shed teeth are functional teeth that are shed either during feeding or are pushed out by a replacement tooth and only the crown and a small portion of the root is preserved.  Same occurs on other reptiles but no idea with ichthyo. 

@RuMert

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Yes. Tooth replacement always involves resorption of the root and implantation tissues. If there is a root, the tooth was embedded in a jawbone at the time of death.

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To add on to what Troodon said, a darker aspect of getting rooted teeth from Asia or Morocco is that you never know when the tooth came out of a deliberately broken skull

 

The reason for this is that a whole jaw or skull is much harder to sell, hence some diggers or even dealers would deliberately smash the fossils apart to extract the rooted teeth which command a respectable value still, and are easier to export

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Kikokuryu
4 hours ago, -Andy- said:

To add on to what Troodon said, a darker aspect of getting rooted teeth from Asia or Morocco is that you never know when the tooth came out of a deliberately broken skull

 

The reason for this is that a whole jaw or skull is much harder to sell, hence some diggers or even dealers would deliberately smash the fossils apart to extract the rooted teeth which command a respectable value still, and are easier to export

Wait, is that known to happen with Moroccan teeth as well? I'm aware of the Mongolian issue, but that seems like it's done because it would be easier for teeth and smaller fragments to pass off as old collection from a banned country. That said, those illicit teeth from Asia don't seem to trickle down into the general market, so it's hard to tell how rampant it really is, or if it's a rare occurrence.

 

But say it was the motive for easier export to avoid custom troubles, I'd imagine they would keep all the pieces of a smashed up a jaw or skull, send it overseas in separate waves, and rebuild it, not just pulverize the skull/jaw to be sold as bone chunks separately just for pristine teeth. They could still sell the pieces separately, but charge higher per piece due to it being all associated.

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3 hours ago, Kikokuryu said:

Wait, is that known to happen with Moroccan teeth as well? I'm aware of the Mongolian issue, but that seems like it's done because it would be easier for teeth and smaller fragments to pass off as old collection from a banned country. That said, those illicit teeth from Asia don't seem to trickle down into the general market, so it's hard to tell how rampant it really is, or if it's a rare occurrence.

 

I see this has a bigger and sad issue in Mongolia other than North Africa (possibly Niger as an exception) where skulls are ultra rare and already fragmented if found.   Most skull elements (maxilla etc) found have no teeth or are broken off..why we've had such a big issue describing dinosaurs or associating teeth with specific taxons.  

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5 hours ago, Troodon said:

I see this has a bigger and sad issue in Mongolia other than North Africa (possibly Niger as an exception) where skulls are ultra rare and already fragmented if found.   Most skull elements (maxilla etc) found have no teeth or are broken off..why we've had such a big issue describing dinosaurs or associating teeth with specific taxons.  

Niger being a possible exception is, in my experience, because Sereno has actually done paleo expeditions to Niger.  Lots of them.   Skulls are rare there as they are in other dinosaur beds.  But Paul and his teams have put in the field time to find them.  I was there twice with him and we found three skulls that I can recall... that is a dozen people working for 2 months.  I think that very little paleo field work has been done in the Moroccan beds, other than Ibrahim's few trips, mostly in search of one dinosaur. 

 

I may be wrong, but this is my take on it. 

  

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On 1/21/2021 at 8:45 PM, -Andy- said:

To add on to what Troodon said, a darker aspect of getting rooted teeth from Asia or Morocco is that you never know when the tooth came out of a deliberately broken skull

 

The reason for this is that a whole jaw or skull is much harder to sell, hence some diggers or even dealers would deliberately smash the fossils apart to extract the rooted teeth which command a respectable value still, and are easier to export

 

I think it's not always that a jaw or a skull is hard to sell.  What's certainly difficult is getting a whole jaw or skull out of the ground at a remote site without further damaging it.  There never seems to be even ground near a big find either.  Also, people digging for money might not recognize the skull pieces lying around with some of the teeth.  An Allosaurus skull can look like a jumble of black chips in the field.  A dinosaur or reptile expert is going to recognize a broken skull piece but how many of the rest of us can?

 

In the early 90's I tagged along with a group of UC Berkeley students on a trip into the Santa Cruz Mountains, CA.  We found a spot uphill with a lot of late Miocene sea urchins exposed.  We chopped out a nice large matrix piece about the size of a mini-fridge with numerous specimens on it and managed to get it to the truck with a stretch of rope and the fortunate find of a large piece of cardboard, using it like a sled and dragging it about a mile.  We were also lucky the site was not far from a horse trail.  I was told it was on display at least for a while somewhere in Walnut Creek. 

 

Jess

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Some of them may also actually have disarticulated pre-burial. A big dinosaur skeleton might take some time to be buried, which could be plenty of time for the periodontal ligaments to decay and teeth to slip out of alveoli. This happens to crocodilians and mammals as well. So you can get scatterings of isolated teeth in some sites and that's just normal and does not necessarily imply bad collection ethics or even destruction of the site by erosion.

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