Need Help For A Strange Megalodon

[Sélacien34]

Hello everyone, i was looking for a solution concerning a tooth that i have found 2 years ago in the Miocene Formation of Loupian, near Montptellier in France. we thought about a possible reshuffle with something like Squalicorax, because the Miocene outcrop is located on a Cretaceous layer but I think the serrations are too strong and the root is not appropriate, which is about 5 mm thick.

Megalodon exists and has already been found in this place but what i have found is particular. I had never really heard talking about parasymphyseal teeth concerning the Otodontidae up to now. But maybe this could be something like that.

The undefined, compressed and blob root really looks like some teeth that i have already seen, There are stronger serrations on one side than the other and the crown is very short. Parasymphyseal, posterior tooth ? What do you think about it ?

Edited August 9, 2013 by Sélacien34

[MarcoSr]

Your tooth is similar in shape and design to what we think are parasymphyseal teeth. My sons personally have a megalodon and auriculatus parasymphyseal. A friend has two Otodus parasymphyseals.

Marco Sr.

[sixgill pete]

I have a tooth that has been positively ID'd as an auriculatus symphyseal that is very similar to what you have. I also have another tooth that has tentatively been ID'd as a meg symphyseal that again is very similar to yours. The one thing they all have in common is the large "bulbous" root.

[Sélacien34]

Your tooth is similar in shape and design to what we think are parasymphyseal teeth. My sons personally have a megalodon and auriculatus parasymphyseal. A friend has two Otodus parasymphyseals.

Marco Sr.

Hello, and thank you for your answers

That's very interesting, i think that very few people believe in such teeth in my country, in any case in non-professional people. But megalodon is rather rare in France, and therefore these positions again more, i imagine. Tell me if I'm wrong, but America is one of the places in the world where we find the most Otodontidae fossils and so, it may be possible to draw some conclusions. I have read some topics on the forum about that :

http://www.thefossilforum.com/index.php?/topic/31992-symphyseal-meg-tooth/

http://www.thefossilforum.com/index.php/topic/26082-help-with-this-tooth/

http://www.thefossilforum.com/index.php?/topic/37755-symphyseal-megalodon/

http://www.fossiel.net/forums/viewtopic.php?TopicID=5850

http://www.thefossilforum.com/index.php?/topic/37781-another-para-or-symphyseal-megalodon/

http://www.thefossilforum.com/index.php?/topic/3380-unidentified-miocene-sharks-tooth/page-2

From what I know, C. appendiculata, the specie considered as the ancestor of the Otodontidae's lineage is credited by the experts with three parasymphyseal teeth on each jaw, there would remain only one for Otodus obliquus, but not for all shark populations as i read here on the forum. After that, it seems that everything is very vague, people found teeth, maybe some have sometimes been regarded as pathological, but these teeth share some common characteristics and are found for different species of this family, and apparently, for O . megalodon too. It's seems there are a few documents and a few representations about that for now, so i would be very interested to see the teeth you speak about if you can and to learn everything you could know about it.

I have a tooth that has been positively ID'd as an auriculatus symphyseal that is very similar to what you have. I also have another tooth that has tentatively been ID'd as a meg symphyseal that again is very similar to yours. The one thing they all have in common is the large "bulbous" root.

Of course, i have seen your tooth, i think it was the first one of this type that i have seen after mine and i was very surprised when i compared them.

At this point, I tried to isolate common characteristics, I found several. After that, I read a comment from a person who took up all these features in one sentence : "In comparison, all of the symphyseal teeth that I've seen have bulbous, undefined roots with quickly-tapering blades. They are usually thicker overall than either a posterior or juvenile tooth of the same size". We can add to that a strong lateral compression (mesio-distally) of the tooth that distinguishes it from the posterior teeth.

I agree with you about the crown, it appears different from one another. Yours has a crown that represents more than half of the tooth where the mine is completely cut off and is less than half. So it seems to be much more difficult to connect them than the roots. As someone said: "The root is as big and looks the same, but the tooth does not exhibit the same curve."

Maybe because there are too few teeth to compare and some belong to different species from the lineage, with crowns more or less wide and with species specific differences. Someone from the French forum has proposed an explication : "the gingival tissues here folds of both sides to the inside of the mouth or sometimes overlap. Consequence: the production of teeth here is very different from one individual to another". Maybe is it the beginning of a response ?

I still noticed a common element in our crowns which was described by one participant:"Really, from the pictures, it looks like there are serrations on both sides, but on one side they are prominent, and the other they are faint, but still visible". And it's also the case for mine. Perhaps this is an additional element of identification?

Now I have seen specimens of O. obliquus, O. Aksuaticus and i think I may have seen some confusions for megalodon, one of them is elsewhere sold as a symphyseal, with teeth that seem to be posterior teeth

In any case, I think there's something real behind this and I'll be very interested in any new knowledge, information and pictures you could add on this topic.

Edited August 10, 2013 by Sélacien34

[MarcoSr]

I went fossil hunting with Mike today and he gave me permission to post the pictures of two Otodus parasymphyseal teeth that he personally collected. They were found in-situ in an Eocene formation years back in close proximity so it is likely they are from the same shark. Daryl took the great pictures below:

Both of my sons have parasymphyseal teeth but I don't have access to them right now to take pictures. The parasymphyseal megalodon is on our website. It is at the bottom of the page of the link below.

http://www.phatfossils.com/species.php?species=Carcharocles%20Megalodon

Marco Sr.

[Al Dente]

I have read some topics on the forum about that :

http://www.thefossilforum.com/index.php?/topic/31992-symphyseal-meg-tooth/

.

I had forgotten this thread. I had posted a picture of a set of associated teeth from Lee Creek that are at the Aurora Fossil Museum.

Here is a close-up of the teeth that are interpreted to be parasymphyseal by the person who built the display. The teeth are odd, they each have incomplete serrations on one side. Sorry about the picture quality, the lighting is bad and the space is cramped. I don't know the exact size of these odd teeth but they are probably between one and two inches.

Edited August 9, 2013 by Al Dente

[Sélacien34]

I went fossil hunting with Mike today and he gave me permission to post the pictures of two Otodus parasymphyseal teeth that he personally collected. They were found in-situ in an Eocene formation years back in close proximity so it is likely they are from the same shark. Daryl took the great pictures below:

Both of my sons have parasymphyseal teeth but I don't have access to them right now to take pictures. The parasymphyseal megalodon is on our website. It is at the bottom of the page of the link below.

http://www.phatfossils.com/species.php?species=Carcharocles%20Megalodon

Marco Sr.

Thank you for those pictures. It appears that there are a few pictures of those teeth but maybe that they are not so rare that it seems, perhaps it is not yet widely known and disseminated by people. This is just a guess. The more pictures of them we could see, the better it is. I have no idea if an expert has spoken on this issue or not for now...

Edited August 10, 2013 by Auspex

[Sélacien34]

I had forgotten this thread. I had posted a picture of a set of associated teeth from Lee Creek that are at the Aurora Fossil Museum.

Here is a close-up of the teeth that are interpreted to be parasymphyseal by the person who built the display. The teeth are odd, they each have incomplete serrations on one side. Sorry about the picture quality, the lighting is bad and the space is cramped. I don't know the exact size of these odd teeth but they are probably between one and two inches.

megs-associated.jpg megs-parasym.jpg

"The teeth are odd, they each have incomplete serrations on one side"

Thank you very much for your answer Al Dente, So it is perhaps features of these teeth. But when i look at it, it seems that those teeth are different from my own little tooth or many other teeth supposed as symphyseal : roots and crowns are much better defined, almost normal, and not bulbous. This may be related to the age of the shark, an ontogenetic factor or specificity of gingival matrix depending on the individual. Still speculative, of course. There may be some people who have some experience of these teeth and who know more, I hope they will speak if this is the case. Obviously, this topic is regularly discussed, I will combine all pictures and information available on this subject. Thank you for the second picture, close up, i haven't seen it yet.

Edited August 11, 2013 by Sélacien34

[siteseer]

Selacien34,

I also agree that your tooth is a parasymphyseal. I can understand skepticism about that identification, and I think you are right that since megalodon is rare at French sites, the chance of finding a tooth of that jaw position becomes quite slim. They tend to be found where the species is abundant. Along with the normal teeth one can find the unusual forms like pathologics, juveniles, and parasymphyseals.

Yes, we can see that the parasymphyseal positions could have been anterior teeth in an ancestor of Cretalamna, but by the time of Otodus, these positions were becoming vestigial as the dentition became more efficient. Doing the same work with fewer teeth was good for the animal because it allowed that energy to be available for another body function.

Yes, the crowns and roots seem to be somewhat variable in shape but consistently asymmetrical (exceptions might exist on that last point). Your quote about gingival tissues is interesting. As a tooth becomes vestigial, less functional, it becomes more reduced in size and form, further affected by the degree of crowding by the adjoining anteriors in that individual. When I think of that, I can see why the parasymphyseals would not show the same form from individual to individual. With Otodus being extremely abundant in the Late Paleocene and Early Eocene phophates of Morocco, relatively few parasymphseals have been reported even in an informal way such as this forum. I think more teeth have been found but ignored because of their small size but I doubt they are common. It appears that much of the population had lost its parasymphyseal positions as the dentition transitioned from tearing-type to cutting-type across the Early Cenozoic. The ancestral ability to generate the file still existed in the genes of the megalodon but the expression of it became as rare as the sight of extra toes on a modern horse or of hind legs on a modern whale. .

Jess

Hello, and thank you for your answers

That's very interesting, i think that very few people believe in such teeth in my country, in any case in non-professional people. But megalodon is rather rare in France, and therefore these positions again more, i imagine. Tell me if I'm wrong, but America is one of the places in the world where we find the most Otodontidae fossils and so, it may be possible to draw some conclusions. I have read some topics on the forum about that :

http://www.thefossilforum.com/index.php?/topic/31992-symphyseal-meg-tooth/

http://www.thefossilforum.com/index.php/topic/26082-help-with-this-tooth/

http://www.thefossilforum.com/index.php?/topic/37755-symphyseal-megalodon/

http://www.fossiel.net/forums/viewtopic.php?TopicID=5850

http://www.thefossilforum.com/index.php?/topic/37781-another-para-or-symphyseal-megalodon/

http://www.thefossilforum.com/index.php?/topic/3380-unidentified-miocene-sharks-tooth/page-2

From what I know, C. appendiculata, the specie considered as the ancestor of the Otodontidae's lineage is credited by the experts with three parasymphyseal teeth on each jaw, there would remain only one for Otodus obliquus, but not for all shark populations as i read here on the forum. After that, it seems that everything is very vague, people found teeth, maybe some have sometimes been regarded as pathological, but these teeth share some common characteristics and are found for different species of this family, and apparently, for O . megalodon too. It's seems there are a few documents and a few representations about that for now, so i would be very interested to see the teeth you speak about if you can and to learn everything you could know about it.

Of course, i have seen your tooth, i think it was the first one of this type that i have seen after mine and i was very surprised when i compared them.

At this point, I tried to isolate common characteristics, I found several. After that, I read a comment from a person who took up all these features in one sentence : "In comparison, all of the symphyseal teeth that I've seen have bulbous, undefined roots with quickly-tapering blades. They are usually thicker overall than either a posterior or juvenile tooth of the same size". We can add to that a strong lateral compression (mesio-distally) of the tooth that distinguishes it from the posterior teeth.

I agree with you about the crown, it appears different from one another. Yours has a crown that represents more than half of the tooth where the mine is completely cut off and is less than half. So it seems to be much more difficult to connect them than the roots. As someone said: "The root is as big and looks the same, but the tooth does not exhibit the same curve."

Maybe because there are too few teeth to compare and some belong to different species from the lineage, with crowns more or less wide and with species specific differences. Someone from the French forum has proposed an explication : "the gingival tissues here folds of both sides to the inside of the mouth or sometimes overlap. Consequence: the production of teeth here is very different from one individual to another". Maybe is it the beginning of a response ?

I still noticed a common element in our crowns which was described by one participant:"Really, from the pictures, it looks like there are serrations on both sides, but on one side they are prominent, and the other they are faint, but still visible". And it's also the case for mine. Perhaps this is an additional element of identification?

Now I have seen specimens of O. obliquus, O. Aksuaticus and i think I may have seen some confusions for megalodon, one of them is elsewhere sold as a symphyseal, with teeth that seem to be posterior teeth

In any case, I think there's something real behind this and I'll be very interested in any new knowledge, information and pictures you could add on this topic.

Edited August 11, 2013 by siteseer

[Sélacien34]

Selacien34,

I also agree that your tooth is a parasymphyseal. I can understand skepticism about that identification, and I think you are right that since megalodon is rare at French sites, the chance of finding a tooth of that jaw position becomes quite slim. They tend to be found where the species is abundant. Along with the normal teeth one can find the unusual forms like pathologics, juveniles, and parasymphyseals.

Yes, we can see that the parasymphyseal positions could have been anterior teeth in an ancestor of Cretalamna, but by the time of Otodus, these positions were becoming vestigial as the dentition became more efficient. Doing the same work with fewer teeth was good for the animal because it allowed that energy to be available for another body function.

Yes, the crowns and roots seem to be somewhat variable in shape but consistently asymmetrical (exceptions might exist on that last point). Your quote about gingival tissues is interesting. As a tooth becomes vestigial, less functional, it becomes more reduced in size and form, further affected by the degree of crowding by the adjoining anteriors in that individual. When I think of that, I can see why the parasymphyseals would not show the same form from individual to individual. With Otodus being extremely abundant in the Late Paleocene and Early Eocene phophates of Morocco, relatively few parasymphseals have been reported even in an informal way such as this forum. I think more teeth have been found but ignored because of their small size but I doubt they are common. It appears that much of the population had lost its parasymphyseal positions as the dentition transitioned from tearing-type to cutting-type across the Early Cenozoic. The ancestral ability to generate the file still existed in the genes of the megalodon but the expression of it became as rare as the sight of extra toes on a modern horse or the hind legs on a modern whale. .

Jess

Thank you very much for your answer Siteseer/Jess I think it gives much more understanding on the subject.

One thing remains difficult to conceive : how a gene which already became obsolete and virtually disappeared from Otodus obliquus would continue further, offering to himself the luxury of disappearing for several million years with Otodus angustidens (no symphyseal tooth found for this species unless I am mistaken) to reappear with O. chubutensis and O. megalodon. Does anyone ever seen such a thing? A useless gene which persists more than 40 million years! Is it conceivable?

Edited August 12, 2013 by Sélacien34

[Auspex]

..Does anyone ever seen such a thing? A useless gene that maintains more than 40 million years! Is it conceivable?

"Junk" DNA persists if its presence creates no liabilities to successful reproduction. Sometimes, even mildly harmful genes can persist if they are linked to seemingly unrelated, beneficial outcomes.

[Sélacien34]

"Junk" DNA persists if its presence creates no liabilities to successful reproduction. Sometimes, even mildly harmful genes can persist if they are linked to seemingly unrelated, beneficial outcomes.

Very interesting information, thank you Auspex.

Just a question more : do we have other exemples of unnecessary functions in the animal kingdom which persist during several ten millions years ?

Edited August 12, 2013 by Sélacien34

[MarcoSr]

One thing remains difficult to conceive : how a gene already become obsolete and virtually disappeared from Otodus obliquus would continue further, offering to himself the luxury of disappearing for several million years with Otodus angustidens (no symphyseal tooth found for this species unless I am mistaken) to reappear with O. chubutensis and O. megalodon. Does anyone ever seen such a thing? A useless gene which persists more than 40 million years! Is it conceivable?

My oldest son found an angustidens that also looks like a parasymphyseal. We had originally thought it was a posterior. Check out the second tooth at the below link to our website.

http://www.phatfossils.com/species.php?species=Carcharocles%20Angustidens

Marco Sr.

[Sélacien34]

I got attention to the issue of this DNA: Initially, the JUNK DNA, noncoding and not used to make proteins was considered unnecessary hardware or unknown role, possible inclusions or relics of past duplication errors. Recently, the Encode consortium showed that in humans, much of this DNA (which represents 98% of our genome) retains a biological role and functional importance, downplaying the qualifier "JUNK." In 2012, these results were refined: 80% of the human genome is functional, linked to "a specific biochemical activity." biological function is poorly understood but has recently appeared to have been underestimated. The non-coding DNA may play a role in the regulation of transcription or genome organization. In addition, some sequences are transcribed into RNA but not translated into protein, and this is the RNA that has a functional role in the cell. Finally, some sequences may have no role or be a role for the moment unknown.

Edited August 11, 2013 by Sélacien34

[Sélacien34]

My oldest son found an angustidens that also looks like a parasymphyseal. We had originally thought it was a posterior. Check out the second tooth at the below link to our website.

http://www.phatfossils.com/species.php?species=Carcharocles%20Angustidens

Marco Sr.

Yes, no doubt possible, it's the same type of tooth, that's great ! Thus, the character has not scored a break for several million years, what seemed even more bizarre.

but beyond the notion of JUNK DNA, I continue to wonder why a function which became useless, an ancestral and obsolete character would have remained like that, anecdotally in a limited number of individuals for a so long period of time. I'll have to find other comparable examples to reinforce this theory in my mind. If anyone knows other exemples?

Edited August 11, 2013 by Sélacien34

[Sélacien34]

After some additional research the concept of a vestigial organ sounds very plausible. The notion of so long period of time bothered me, but such stuctures can persist for millions of years and there is probably a link with the pseudogenes (JUNK DNA).

These structures are typically in a state, shape or condition degenerated, atrophied, or rudimentary. I almost forgot that human himself has very many of them, whose origins go back to a much earlier time before humans are born. Some of these characters also retain some usefulness: amnion, Appendix vestige of the cecum of herbivores. And others not: wisdom teeth, the coccyx, the nictitating membrane of the eye.

Other examples of vestigial structures that persist for many millions of years : back legs atrophied in whales and manatees, the wings of Apterygiformes etc ... So why not symphysis teeth in Otodontidae !

There are even vestigial behaviors, whose function has been lost since a very long time, as the last traces of sexuality : in lizards a coupling sham between two female stimulates reproduction. In the case of dandelions, females breed alone, but the production of pollen remains, indicating a residue of sexual reproduction. Other residual gendered phenomenon in some species of fish: the egg is stimulated by the sperm of a sexual species close, but the contact is without combination of genetic material. gender would be an ancestral character, become unnecessary operation of these species.

Some tracks on the genetic plane: The expression of a gene can be guided by a chemical modification of DNA: methylation of cytosine to 5-methylcytosine5 CG dimers in the DNA. The number and how these are methylated bases often influence the expression of genes composed of these bases: low methylation is most often translated by a strong expression of the gene, while a high level of methylation inactivates the gene. However there are examples where a high methylation has no effect on the expression level. The DNA methylation is a major player in the establishment of genomic imprinting, a mechanism by which the expression of a will depend on the parental origin of the gene. The DNA methylation is often observed in repeated genes and may be a natural mechanism for the inactivation of unnecessary genes. The methylation of DNA can either be inherited or created or modified in response to an environmental factor. In the latter case, the change created by the environment is transmitted to offspring in the same way as a mark inherited.

An inactive pseudogene means a gene within a genome, due to genetic alterations non-functional and therefore unable to drive the expression of a protein making. These are sometimes called "fossil genes" by estimating that as a result of these changes and the loss of character encoding, they are more significant role in the body one play. As such, they belong to the non-coding part of the genome is sometimes mistakenly called "junk DNA." At least in some cases, they actually seem to be able to keep even more functions.
Pseudogenes may be present in large numbers in a genome. And humans, we know 21,000 active genes and 19,000 pseudogenes, most of which are considered inactive or useless. This figure could increase with better understanding of our genome. There are several reasons why pseudogenes share more or less important parts of the genome, with existing genes in humans, or present in other species. They are a consequence of the evolution of the organization and its adaptation to its environment.

- They may be remnants of genes become obsolete, ancestors of current genes or fragments of genes from other species (viruses, bacteria ...) inserted into our genome;
- They also result from errors in replication of genetic material.
- Some might be fragments of sequences apparently ignored by the body, but possibly active under certain conditions.

Edited August 12, 2013 by Sélacien34

[siteseer]

Marco Sr. offers a specimen and I would assume more have been found though sites for angustidens are fewer (and of those very few are as productive) than for megalodon. Depending on how angustidens is defined, we are still looking at about ten million years for a chronologic range but megalodon (again depending on the definition) existed across the Miocene and into the Pliocene - perhaps twice as long. I would think some of the Summerville, South Carolina collectors, particularly those who collected during the 80's and early 90's (when collecting was less restricted and before drought conditions of the late 90's persisted into the 2000's) might have parasymphyseals that they considered posteriors or small pathologics.

The Summerville material comes from the Chandler Bridge Formation (Late Oliocene, Chattian age) and might be the most productive layer for sharks of that age in the world..

Thank you very much for your answer Siteseer/Jess I think it gives much more understanding on the subject.

One thing remains difficult to conceive : how a gene already which became obsolete and virtually disappeared from Otodus obliquus would continue further, offering to himself the luxury of disappearing for several million years with Otodus angustidens (no symphyseal tooth found for this species unless I am mistaken) to reappear with O. chubutensis and O. megalodon. Does anyone ever seen such a thing? A useless gene which persists more than 40 million years! Is it conceivable?

[siteseer]

Yes, whales have only a remnant of a pelvis and it is unconnected to the rest of the skeleton. On rare occasions an individual whale is born with more developed hind limbs. Animal species that have lived in the deepest parts of cave systems have only vestigial eyes. It is not that an animal loses its eyesight because it lives in a cave. Over generations individuals that might have been born with eye disorders or perhaps even nonfunctional eyes still survived and mated successfully because blindness is not an issue where there is no light. The energy that once went to its eyes could go to some other function that might be helpful in its environment.

Insects of the order Diptera, true flies, have two wings. These flies have a tiny pair of appendages called halteres which are situated exactly where the second pair of wings would occupy in a 4-winged insect. Halteres help the fly orient itself during flight especially during high performance maneuvers. It has been demonstrated that they are actually vestigial wings, not only identical to wings in an embryo but they will develop into wings when a specific gene is naturally or artificially deactivated - evidence of having a 4-winged ancestor.

After some additional research the concept of a vestigial organ sounds very plausible. These structures are typically in a state, shape or condition degenerated, atrophied, or rudimentary. I almost forgot that man himself has very many, whose origins go back to a much earlier time in its appearance as a man. Some of these characters also retain some usefulness: amnion. And others not: wisdom teeth, the coccyx, the nictitating membrane of the eye.
Other examples of vestigial structures that persist for many millions of years back legs atrophied in whales and manatees, the wings of kiwis etc ... So why not symphysis teeth in Otodontidae

[Sélacien34]

Marco Sr. offers a specimen and I would assume more have been found though sites for angustidens are fewer (and of those very few are as productive) than for megalodon. Depending on how angustidens is defined, we are still looking at about ten million years for a chronologic range but megalodon (again depending on the definition) existed across the Miocene and into the Pliocene - perhaps twice as long. I would think some of the Summerville, South Carolina collectors, particularly those who collected during the 80's and early 90's (when collecting was less restricted and before drought conditions of the late 90's persisted into the 2000's) might have parasymphyseals that they considered posteriors or small pathologics.

The Summerville material comes from the Chandler Bridge Formation (Late Oliocene, Chattian age) and might be the most productive layer for sharks of that age in the world..

Your arguments perfectly explain why the symphysis teeth seemed lacking in this species. I considered the fact that the teeth of Otodus angustidens, relatively rare in coastal sediments and reflecting a preference for deeper pelagic waters could be an explanation, but compared to its ancestor O. auriculatus or even O. Sokolovi rarer, my hypothesis was not convincing.

I think I have now enough evidence in my possession to validate the identification of my tooth as symphysis tooth and also enough arguments to support the thesis of the existence of these teeth in Otodontidae lineage. Thank you all, but if other elements appear on the subject, this post is obviously made ​​for that

Edited August 11, 2013 by Sélacien34

[Auspex]

The shark genome is a very conservative, very ancient thing, and very stable compared to genetic 'newcomers' whose lines arose in environments undergoing rapid change. Their DNA is more patient

[Sélacien34]

The shark genome is a very conservative, very ancient thing, and very stable compared to genetic 'newcomers' whose lines arose in environments undergoing rapid change. Their DNA is more patient

Right !

Edited August 11, 2013 by Sélacien34

[Sélacien34]

Some new informations about my tooth from B. Kent :

"There are two possibilities for your tooth; it could either be a symphyseal or a pathological tooth. Of the two a pathological tooth seems more likely. Symphyseals are not known from megalodon, but are present in the related genera Parotodus and Otodus. But symphyseal teeth tend to be both narrow (like your tooth) and with an erect crown (which your tooth does not have). Pathological teeth are produced by damage to the jaws. They can be much more variable and can be of quite bizarre sizes and shapes. I have seen teeth roughly similar to yours (although not as small) from megalodon, Parotodus and Otodus."

It seems that the most simple answer is sometimes the good one even if we prefer the first

[sixgill pete]

Some new informations about my tooth from B. Kent :

"There are two possibilities for your tooth; it could either be a symphyseal or a pathological tooth. Of the two a pathological tooth seems more likely. Symphyseals are not known from megalodon, but are present in the related genera Parotodus and Otodus. But symphyseal teeth tend to be both narrow (like your tooth) and with an erect crown (which your tooth does not have). Pathological teeth are produced by damage to the jaws. They can be much more variable and can be of quite bizarre sizes and shapes. I have seen teeth roughly similar to yours (although not as small) from megalodon, Parotodus and Otodus."

It seems that the most simple answer is sometimes the good one even if we prefer the first

If this tooth is in fact pathologic, and pathologies are produced by damage tot he jaws; then how is it that so many of these teeth over a range of species look so much alike? The odds of two pathologic teeth looking almost identical even from the same shark must be astronomical. But from different species?

Just my thoughts.

[Sélacien34]

I also thought about what you say, it is a fact, there are different characters on those teeth that seem to be common among different Otodontidae's species , they have been described here . Even Cretoxyrhina from Cretaceous presents this type of roots "features" . I would like to see it for C. appendiculata but I haven't found any representations.

O. obliquus : so what is that ? Is it also a pathological tooth ?

I have thought that some particular diseases or injuries could perhaps reproduce some effects and some close forms on tooth development .

I also thought of an ontogenetic cause, perhaps that the teeth represent an early stage of development where roots and crowns are not yet fully developed, as Welton and Farish have showed here for Paraisurus . This could explain the characteristics of these roots, which are those that are found more broadly.

The counter argument of Kent on the smallness of the crown of my tooth is concrete, but I feel that we need to widen the question. I just asked the question to the specialist basically, just to know his opinion. Your comment now pushes me to present arguments and photos , thanks for that, I 'll tell you more later.

Edited April 15, 2014 by Sélacien34

[Sélacien34]

The message is sent.

Edited April 19, 2014 by Sélacien34