A Bent Shark Tooth- Or?

[ynot]

I made a second trip to Shark Tooth Hill and this tooth presented itself to Me. It is the first tooth that I have found that looks like this.

The tooth is 1/2 inch wide by 3/8 inch tall by 1/4 inch thick.

With My record I will not say what I think it is !

Thanks in advance for any help.

Tony

[siteseer]

Tony,

Like I said in the other thread, that is a very rare tooth form from the bonebed. I think it could be a Hemipristis symphyseal. I'll crack some books for that one.

Jess

I made a second trip to Shark Tooth Hill and this tooth presented itself to Me. It is the first tooth that I have found that looks like this.

The tooth is 1/2 inch wide by 3/8 inch tall by 1/4 inch thick.

DSCF2869.JPG

With My record I will not say what I think it is !

Thanks in advance for any help.

Tony

Edited May 7, 2015 by siteseer

[ynot]

Tony,

Like I said in the other thread, that is a very tooth form from the bonebed. I think it could be a Hemipristis symphyseal. I'll crack some books for that one.

Jess

Hey-lo Jess,

Than You for the reply. I looked at the Physogaleus on the web and do not find any similarity with this tooth. The tooth in question has no serrations, and the curve in the tooth is more pronounced and closer to the base of the crown. The root almost seams to be sideways to the crowns curve.

Thanks for the help,

Tony

Edited May 7, 2015 by ynot

[siteseer]

Some sharks don't always have symphyseal teeth. I was thinking Hemipristis but I haven't seen a tooth like that from other deposits where it comes from. I would expect it to have a narrower and maybe longer crown - hard to say. The other thing I thought of is that it could just have some weird wear. It will be interesting to read other comments.

Hey-lo Jess,

Than You for the reply. I looked at the Physogaleus on the web and do not find any similarity with this tooth. The tooth in question has no serrations, and the curve in the tooth is more pronounced and closer to the base of the crown. The root almost seams to be sideways to the crown.

Thanks for the help,

Tony

[ynot]

Some sharks don't always have symphyseal teeth. I was thinking Hemipristis but I haven't seen a tooth like that from other deposits where it comes from. I would expect it to have a narrower and maybe longer crown - hard to say. The other thing I thought of is that it could just have some weird wear. It will be interesting to read other comments.

There is a small chip on one edge and the root may be somewhat worn but there is no other indication of wear on the tooth.

Edited May 8, 2015 by ynot

[sseth]

This tooth looks pathalogic. If I am seeing the mark on the front correct, it could have a stingray scar on it.

Just an opinion.

[ynot]

This tooth looks pathalogic. If I am seeing the mark on the front correct, it could have a stingray scar on it.

Just an opinion.

All opinions are welcome, thanks.

[Al Dente]

I think it is a deformed tooth.

[ynot]

I think it is a deformed tooth.

Thanks for the thoughts. I can not say for sure because I am not educated in this field but I am trying to learn about them.

Tony

[Diceros]

I'm surprised no one has suggested a really reduced shark tooth, like from a whale shark (Rhincodon) or basking shark (Cetorhinus). My guess would be the latter, as the crown doesn't sit as far forward on the root as it does in Rhincodon. Also, I think basking shark teeth and gill rakers are fairly common at Sharktooth Hill. Don't lots of West Coast people on FF collect there? Someone must have seen one of these.

[ynot]

I'm surprised no one has suggested a really reduced shark tooth, like from a whale shark (Rhincodon) or basking shark (Cetorhinus). My guess would be the latter, as the crown doesn't sit as far forward on the root as it does in Rhincodon. Also, I think basking shark teeth and gill rakers are fairly common at Sharktooth Hill. Don't lots of West Coast people on FF collect there? Someone must have seen one of these.

Thanks for the input.

The teeth of the Whale shark (Rhincodon) and the Basking shark (Cetorhinus) are much smaller than this tooth. I have found quit a few of the Basking shark teeth in the micro-matrix that I collected in February and am sure that the tooth in question is not one of them. After looking at elasmo's Whale shark page I am also sure it is not that either.

There is one shark on elasmo that does seem to be a close fit-- the Mega-mouth (Megachasma sp.) , But that one is not supposed to be in the round mountain silt.

Does anybody have any thoughts on that possibility?

Thank Y'all,

Tony

[siteseer]

Al Dente,

I don't think it's deformed because I happen to have a tooth just like it. I looked at elasmo. Though there isn't a close shot, the first lower tooth of Hemipristis elongatus seems the closest match I have seen so far.

Jess

I think it is a deformed tooth.

[siteseer]

Tony,

Also, the root is wrong for Rhincodon and Cetorhinus. You can find a lot of Cetorhinus in the bonebed. Rhincodon has never been reported from there though you can't eliminate it as a possibility just for that reason.

The root is also wrong for Megachasma. The root on your tooth has the reduced look of a symphyseal.

Jess

Thanks for the input.

The teeth of the Whale shark (Rhincodon) and the Basking shark (Cetorhinus) are much smaller than this tooth. I have found quit a few of the Basking shark teeth in the micro-matrix that I collected in February and am sure that the tooth in question is not one of them. After looking at elasmo's Whale shark page I am also sure it is not that either.

There is one shark on elasmo that does seem to be a close fit-- the Mega-mouth (Megachasma sp.) , But that one is not supposed to be in the round mountain silt.

Does anybody have any thoughts on that possibility?

Thank Y'all,

Tony

[ynot]

Tony,

Also, the root is wrong for Rhincodon and Cetorhinus. You can find a lot of Cetorhinus in the bonebed. Rhincodon has never been reported from there though you can't eliminate it as a possibility just for that reason.

The root is also wrong for Megachasma. The root on your tooth has the reduced look of a symphyseal.

Jess

Hey Jess,

If the root has been deformed by wear it looks as if it could fit within the Megachasma range of shape. when I look at the Hemipristis tooth set I see teeth that look more rounded, elongated and not as angled crown to root.

I have to say that I can not place it in the Hemipristis sp. family unless I could see more definitive proof.

I appreciate all of Your assistance with the ID requests that I have been posting.

Tony

[siteseer]

Hey Tony,

It's not Megachasma because if we assume the tooth was rather heavily worn, abraded on the mesial and distal sides to the extent seen on your tooth, then the crown would also be damaged on those sides because the crown in Megachasma flares out to those sides near its base.

The tooth I have is slightly shorter than yours but about the same in other dimensions. Like your tooth, there is a shallow groove or concavity on one side of the crown while the opposite side is slightly convex. On my tooth there is an incomplete cutting edge on one side. Those are clues. It's hard to tell in your photo whether there is a cutting edge on both sides.

I looked at a set of jaws of a modern Hemipristis (H. elongatus) and there is a little tooth (smaller than your or my specimen) with a short crown but the root cannot be clearly seen because it is jammed in between the lower anteriors. When I look at the set on elasmo.com, there is an empty space at the symphysis, while in the jaws I held, the symphysis was packed with teeth. Hemipristis elongatus is not a commonly fished species as far as I know but maybe someone else on the forum has a set and can add to the discussion on the modern form or a fossil tooth similar to yours from another site.

Whatever this tooth is, it is very unusual. It is not a worn-off lateral cusplet of a larger tooth. Al Dente and Sseth think it's pathologic and that is a possibility but whatever that chance is, it got cut in half by the fact that I have a tooth just like it. There are similar pathologies but not virtually-identical ones. If it is a pathology, I would think someone by now would have narrowed down the genus. I still have to consider it. Could it be a juvenile Hexanchus upper parasymphyseal?

I will try to provide a photo of my tooth soon. A longtime Sharktooth Hill collector and old friend gave it to me. He was collecting the bonebed before I was born (and I remember Nixon). He said he didn't find another one like nor did he see another one like in other people's collections nor in any publication he has ever seen. Years ago, he drew it for me and I could say what it was. Now, with it in my hand, I cannot say for sure what it is.

I also had the opportunity to examine the unusual teeth that the late Bob Ernst found in his quarries from 1993 to April 2007. He had an incredible eye for anything weird from the bonebed from an unfamiliar bone end or a rare shark tooth and he never showed me a specimen like this.

Jess

Hey Jess,

If the root has been deformed by wear it looks as if it could fit within the Megachasma range of shape. when I look at the Hemipristis tooth set I see teeth that look more rounded, elongated and not as angled crown to root.

I have to say that I can not place it in the Hemipristis sp. family unless I could see more definitive proof.

I appreciate all of Your assistance with the ID requests that I have been posting.

Tony

[ynot]

Hey Tony,

It's not Megachasma because if we assume the tooth was rather heavily worn, abraded on the mesial and distal sides to the extent seen on your tooth, then the crown would also be damaged on those sides because the crown in Megachasma flares out to those sides near its base.

The tooth I have is slightly shorter than yours but about the same in other dimensions. Like your tooth, there is a shallow groove or concavity on one side of the crown while the opposite side is slightly convex. On my tooth there is an incomplete cutting edge on one side. Those are clues. It's hard to tell in your photo whether there is a cutting edge on both sides.

I looked at a set of jaws of a modern Hemipristis (H. elongatus) and there is a little tooth (smaller than your or my specimen) with a short crown but the root cannot be clearly seen because it is jammed in between the lower anteriors. When I look at the set on elasmo.com, there is an empty space at the symphysis, while in the jaws I held, the symphysis was packed with teeth. Hemipristis elongatus is not a commonly fished species as far as I know but maybe someone else on the forum has a set and can add to the discussion on the modern form or a fossil tooth similar to yours from another site.

Whatever this tooth is, it is very unusual. It is not a worn-off lateral cusplet of a larger tooth. Al Dente and Sseth think it's pathologic and that is a possibility but whatever that chance is, it got cut in half by the fact that I have a tooth just like it. There are similar pathologies but not virtually-identical ones. If it is a pathology, I would think someone by now would have narrowed down the genus. I still have to consider it. Could it be a juvenile Hexanchus upper parasymphyseal?

I will try to provide a photo of my tooth soon. A longtime Sharktooth Hill collector and old friend gave it to me. He was collecting the bonebed before I was born (and I remember Nixon). He said he didn't find another one like nor did he see another one like in other people's collections nor in any publication he has ever seen. Years ago, he drew it for me and I could say what it was. Now, with it in my hand, I cannot say for sure what it is.

I also had the opportunity to examine the unusual teeth that the late Bob Ernst found in his quarries from 1993 to April 2007. He had an incredible eye for anything weird from the bonebed from an unfamiliar bone end or a rare shark tooth and he never showed me a specimen like this.

Jess

Hey-lo Jess,

First I would like to express My gratitude for all the effort that You have put into this, and apologize for My end of things.

On another post that I put up the teeth were identified as being Hemipristis elongatus and Hexanchus. I have taken some more photos of each of those with the tooth of this post for comparison. I tried to get the same angle for each column. Also the scale of each column is the same as all three of the teeth were in one shot.

The top row is the tooth in question. The center row is the Hexanchus, the bottom row is Hemipristis elongatus

One side of the tooth has a cutting edge about 3/4 of the length and the other side has a cutting edge about 1/4 of the length. Notice the fatter more squat appearance and more angled bend of the unidentified tooth.

I do not see how these teeth could come from the same type shark.

Thank You again,

Tony

[siteseer]

You're comparing your tooth to other teeth you have. That won't work in this case because the tooth in question is very unusual and the comparison material is the usual stuff. Comparing it to other teeth is a good start, though. You don't need to apologize for anything. You're asking questions. You want to understand the reasoning. Some people would be content just writing monkey tooth on the label because some guy on the web said monkey tooth.

Hemipristis and Hexanchus are two sharks that show tooth variation within the upper and lower jaws from anterior to posterior jaw positions. Hemipristis lower symphyseal is still my best guess but that is based partly on because it doesn't match what I've seen before of other genera from the bonebed. What I have seen of Hemipristis lower symphyseals (still haven't seen a clear photo of a modern one) hasn't eliminated it as a possibility. I offered Hexanchus as an alternative. Another alternative could be that it is an undescribed form or perhaps some odd dermal denticle but it looks like a tooth to me and it would seem more likely to be something unusual of a known shark rather than a tooth of one new to science.

I hope to see more discussion of this tooth from other members.

Hey-lo Jess,

First I would like to express My gratitude for all the effort that You have put into this, and apologize for My end of things.

On another post that I put up the teeth were identified as being Hemipristis elongatus and Hexanchus. I have taken some more photos of each of those with the tooth of this post for comparison. I tried to get the same angle for each column. Also the scale of each column is the same as all three of the teeth were in one shot.

The top row is the tooth in question. The center row is the Hexanchus, the bottom row is Hemipristis elongatus

abcd.jpg

One side of the tooth has a cutting edge about 3/4 of the length and the other side has a cutting edge about 1/4 of the length. Notice the fatter more squat appearance and more angled bend of the unidentified tooth.

I do not see how these teeth could come from the same type shark.

Thank You again,

Tony

[ynot]

You're comparing your tooth to other teeth you have. That won't work in this case because the tooth in question is very unusual and the comparison material is the usual stuff. Comparing it to other teeth is a good start, though. You don't need to apologize for anything. You're asking questions. You want to understand the reasoning. Some people would be content just writing monkey tooth on the label because some guy on the web said monkey tooth.

Hemipristis and Hexanchus are two sharks that show tooth variation within the upper and lower jaws from anterior to posterior jaw positions. Hemipristis lower symphyseal is still my best guess but that is based partly on because it doesn't match what I've seen before of other genera from the bonebed. What I have seen of Hemipristis lower symphyseals (still haven't seen a clear photo of a modern one) hasn't eliminated it as a possibility. I offered Hexanchus as an alternative. Another alternative could be that it is an undescribed form or perhaps some odd dermal denticle but it looks like a tooth to me and it would seem more likely to be something unusual of a known shark rather than a tooth of one new to science.

I hope to see more discussion of this tooth from other members.

Thank You Jess--

Tony

[ynot]

I thought to bring this back to the top of the forum to see if anybody could shed some light on the identity of this tooth.

Thanks for any past and future help,

Tony

[TyrannosaurusRex]

Very interesting.

[siteseer]

Bumping this thread now that Marco Sr. and maybe a few other shark collectors who haven't seen it are taking a look at the forum

[ynot]

Bumping this thread now that Marco Sr. and maybe a few other shark collectors who haven't seen it are taking a look at the forum

Thank You Jess.

I had a thought about the identity of this as being a Hexanchus Andersoni symphyseal.

My reasons for this being....

1) I did find a picture of a modern Hexanchus jaw set that showed an upper symphyseal that looked similar. (on jelasmo)

2) The tooth does not seem to be found at any other sites of the same age. So it would stand to reason that it is a shark that is unique to Sharktooth Hill.

3)There are very few that have surfaced within the bonebed at Sharktooth Hill. So it is not a common species there.

Does anybody have any thoughts on this hypothesis?

Thank Y'All,

Tony

[isurus90064]

Hello all,

Sorry for the not so great quality of the pics below. Not easy to get those small ones photographed (scanner is busted). The tooth in the pictures below is the one Bob Ernst found that's suspected to be Megachasma. Based on partial cutting edges, D-shaped X section, root orientation, volume and apparent histology (in so far as it is visible), acute crown angle, overall size, crown bump/"cusp", this looks like Megachasma to me.

The tooth is a little over 3/8" across the root base.

Edited August 19, 2015 by isurus90064

[ynot]

Hello all,

Sorry for the not so great quality of the pics below. Not easy to get those small ones photographed (scanner is busted). The tooth in the pictures below is the one Bob Ernst found that's suspected to be Megachasma. Based on partial cutting edges, D-shaped X section, root orientation, volume and apparent histology (in so far as it is visible), acute crown angle, overall size, crown bump/"cusp", this looks like Megachasma to me.

The tooth is a little over 3/8" across the root base.

Hey-hi issurus,

Thank You for the reply!

Are You saying the tooth in question in this string is a Megachasma?

When I compare Your tooth to mine I do not see the same thing. My tooth has no shoulder on the crown base and the "curved" area is in the crown shape not the crown/root junction as is shown in Your pictures.

Bumping this thread now that Marco Sr. and maybe a few other shark collectors who haven't seen it are taking a look at the forum

Hey-hi Jess,

I would like to see a photo of the tooth that You have that Is the same as mine, could You please post one.

Thanks Y'All!!

Tony

[isurus90064]

Hello Tony,

I think there is a good chance you'll never know for sure. Going by individual tooth characters and eliminate respective candidates, especially when comparing symphyseals to "garden variety" examples, is at best very difficult. I guess all I am saying is that there is a chance it's Megachasma :-).

I think the lack of crown expansion onto the shoulder could be due to the fact that your tooth may indeed come from a place close to the symphysis. Not just that, the entire tooth is laterally compressed as if it had to fit in the limited space available.

Regarding curvature, the crown curvature is non-existent on your tooth, however the crown to root angle is similar on both teeth (acute, with a flat area on the labial side).