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Megalodon Shell Tooth?


Nimravis

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@siteseer I was looking at a thread from 2010 that you were participating in and it was about a “shell tooth”. I found this piece a couple weeks ago, while in Florida, collecting at a Bone Valley site. 
 

I was wondering if there actually are “shell teeth”, and if so, do you think that this is one? Thanks for any assistance.

 

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Hi,

 

I don’t know what you call “shell teeth”, but in your picture it’s a tooth in formation, so at least on the 4th row (or so) inside a jaw.

The teeth begin to form from the enamelled surface, and at the end only the roots form.

 

The forming teeth are covered with a "gingival tissue" when the shark is alive. They are only discovered (when the rows are moving forward) when they have completed their formation and are able to "work".

 

Coco

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OUTIL POUR MESURER VOS FOSSILES : ici

Ma bibliothèque PDF 1 (Poissons et sélaciens récents & fossiles) : ici
Ma bibliothèque PDF 2 (Animaux vivants - sans poissons ni sélaciens) : ici
Mâchoires sélaciennes récentes : ici
Hétérodontiques et sélaciens : ici
Oeufs sélaciens récents : ici
Otolithes de poissons récents ! ici

Un Greg...

Badges-IPFOTH.jpg.f4a8635cda47a3cc506743a8aabce700.jpg Badges-MOTM.jpg.461001e1a9db5dc29ca1c07a041a1a86.jpg

 

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Another explanation is this tooth could be the result of weathering or leaching of the inner part of the tooth leaving just the resistant enamel. The root marks on the labial side of this tooth indicates this tooth was at one time shallowly buried, where weathering can occur.

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Both great points! Virtually all of the hollow enamel-only fossil shark teeth that I have in my collection are teeth that were forming when the shark died. As Coco mentioned shark teeth form "inside out" with the enameled surface being created before the dentine is added inside and completed with a root. Given the number of teeth that a mature shark may have lost in its lifetime--I've seen numbers like 20,000-30,000 (or more) bandied about--finding teeth that were forming in the jaws when the shark died account for a very tiny percentage of the total. Though they are not as impressive as a "complete" tooth, I think they are extra special as you have a little more information available in teeth like these.

 

So there is no possible confusion, the "root marks" as Al Dente mentioned are plant roots (not tooth roots). The scrawled markings on the enamel are where plant roots were in contact with the tooth after it had left the shark's jaw. This is an extra bit of taphonomic information indicating that at one time this tooth was likely buried high and dry where plants could reach their roots down to the tooth and leach some minerals out of the enamel. Actually, it is the symbiotic mycorrhizae that work with the plants to extract minerals from the environment. ;)

 

https://en.wikipedia.org/wiki/Mycorrhiza

 

The tooth is not very tall as you can see the discolored edge where the enamel was stopping and the root would likely have attached so this seems to indicate this might have been a more posterior tooth. Lots to tell from a simple tooth. :)

 

 

Cheers.

 

-Ken

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Shark teeth develop like mammal teeth -- from the outside in.  First, the enamel shell is laid down, then it is filled in with dentine, then the root develops.  I think the tooth in question was in the first stage of development.  It is unlikely that interior orthodentine could weather so clean.  Shielded by enameloid, the interior orthodentine is very durable.  Even without the enameloid shield, the orthodentine is very durable.  Think about all the damaged shark teeth you've recovered that are missing enameloid, but the interior orthodentine is present. 

 

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http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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@Coco @Harry Pristis @digit and @Al Dente thank you very much you the information, it is good when I learn something new. As a matter of fact, when I found it a couple weeks ago, a person at the site said, “oh cool shell tooth”, it went in one ear and out the other since I was busy collecting. It was not until last night that I was checking real old posts of “Members Collections”, that I came across a post and it had the same type of tooth, but larger and thought I would ask about it. See pic below for the title of the post. Thanks again.

 

AC4436BF-652B-4C3A-AE99-113F2CEDF784.thumb.jpeg.971c9a5358d0549f621270a3f44a847a.jpeg

Edited by Nimravis
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Shell tooth or File tooth - I heard both that day! Found one as well - though mine is a traditional bone valley blue, no cool pattern.

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Fossils? I dig it. :meg:

 

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I've heard the term 'file tooth' more than 'shell tooth' as it refers to newer teeth forming further back in the file (column) of teeth at a particular position within the jaw.

 

 

Cheers.

 

-Ken

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It sounds like the question has been answered.  Yes, a tooth from farther back in the file.

 

I guess it's possible some teeth we find with hollow crowns are what's left after the dentine and root eroding away but I agree with Harry that it's unlikely that it would weather away so cleanly.  Think about all the teeth we see in which the roots are gone but the enameloid and dentine are still intact. 

 

I think "shell tooth" is just an informal term and "file tooth" can refer to any tooth in the file but would be understood as referring to one behind the functional tooth.  Over the years, I think I've heard the informal term "husk" or "tooth husk" used more often than any other.  They've always been said to be evidence of a jaw having been preserved but later largely weathered away with all the teeth scattering.

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I've collected teeth at sites where all of them are hollow enamel shells. None looked this good though so assume that the file tooth designation is a good one. Particularly if all the other teeth in the area are complete.

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12 hours ago, Al Dente said:

The root marks on the labial side of this tooth indicates this tooth was at one time shallowly buried, where weathering can occur.

I suppose the specimen was laid down to the sediments with the labial side up. It looks to me, that this side had bioerosional marks vs. the lingual side wich has no similar marks, so it was more exposed to bioerosion than geoligical erosion/weathering. Am I wrong?

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" We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. "

Thomas Mann

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37 minutes ago, abyssunder said:

so it was more exposed to bioerosion than geoligical erosion/weathering. Am I wrong?

 

It has been a long time since I've studied soil horizons in class but if I remember correctly, the zone where soil is leached occurs in the upper soil horizons where plant roots would also be found. I'm still convinced the majority of these hollow fossil shark teeth are the result of leaching and not incompletely formed teeth. When I find hollow teeth there are usually an abundance of them at a site and the hollow teeth are usually lighter in color than rooted teeth. I've processed modern shark jaws and the incompletely formed teeth are usually very fragile. I think most would be crushed during burial and fossilization.

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