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Unusual Tiger Shark Tooth

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Al Dente

Daryl

I have two thoughts on this. One, if you find 20,000 teeth from one locality, there will be a few that have some pathology. My second thought is these two look very much like G. mayumbensis. The larger size of the one tooth would fit very well with G. mayumbensis. The problem with this identification is G. mayumbensis is Oligocene to early Miocene and the cliffs are younger than this. Could these have been reworked from older sediment? In North Carolina we have similar teeth from the Oligocene that are identified as Galeocerdo casei. G. casei is probably the same as G. mayumbensis.

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Al Dente

I just noticed that according to the time stamps of these posts, I responded to your post before you posted it. If I can time travel, then obviously so can your shark tooth, therefore, it wouldn't be unusual for an Oligocene tooth to be in the Miocene. :D

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cowsharks

I've had a couple of fossil tiger shark teeth in my collection for some years now that I had set aside becuase they look a bit different than all the other tiger shark teeth I have. These teeth come from Calvert Cliffs. There are two primary fossil tiger shark species that we find there; Galeocerdo aduncus and Galeocerdo contortus (aka P. contortus). I have approximately 20,000 tiger shark teeth from Calvert Cliffs, and almost half of them are of the "aduncus" variety which closely resemble the "modern" tiger shark G. cuvier.

Below are a couple of pics of one large tiger shark tooth that looks a bit different because of the size of the serrations, the angle of the crown, etc. I have compared it to all of my other tiger sharks and was able to come up with only one similar but smaller tooth. Both of these teeth oddly enough resemble each other in their overall shape and profile, coarse serrations along the mesial edge of the crown, etc. For comparison purposes, I inserted a "normal or common" looking aduncus type tiger shark tooth in between these two teeth in the one pic for comparison.

For the heck of it I also took a look at all of my G. cuvier teeth from Lee Creek, some 225 teeth in total with a great variety of positions, and none of them really resemble either of these two teeth from Calvert Cliffs.

So, it's possible that these two teeth are just anomalies and happen to be different from all of the otehrs I have found in 16 years of collecting. The larger of the two teeth in question is really an anomaly due to its sheer size, 1" long by 1" wide. It is much larger than my largest "aduncus" type tooth, and approaches the size of some G. cuvier teeth from Lee Creek.

Curious to know if anyone has any opinions about these two teeth, or have any similar in their collection.

Daryl.

post-2077-0-95946500-1327407077_thumb.jpg

post-2077-0-22207100-1327407113_thumb.jpg

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siteseer

That's the great thing about collecting one area over time. You find a few oddballs among the common stuff. Is it possible that a few teeth have washed out of a younger formation (old enough to still contain aduncus and contortus but young enough to yield something along the line to cuvier)?

I've seen a few oddball tiger shark teeth out of the Bone Valley Formation too like a cuvier-like specimen but with more of a weak S-surve to the cusp. I played with the idea that it was perhaps a transitional tooth somewhere in the aduncus-contortus-cuvier group depending on how you think of the lineage/lineages but it could be just a tooth from a lucky individual that lived to be an old, unusually large tiger. If you look at some of the larger makos, especially those over 3 inches, they do not look proportional to smaller adult teeth (varying from familiar shapes). They can almost look stretched or strangely-broad at mid-crown, coming to more of an overall spearhead-like shape.

I've had a couple of fossil tiger shark teeth in my collection for some years now that I had set aside becuase they look a bit different than all the other tiger shark teeth I have. These teeth come from Calvert Cliffs. There are two primary fossil tiger shark species that we find there; Galeocerdo aduncus and Galeocerdo contortus (aka P. contortus). I have approximately 20,000 tiger shark teeth from Calvert Cliffs, and almost half of them are of the "aduncus" variety which closely resemble the "modern" tiger shark G. cuvier.

Below are a couple of pics of one large tiger shark tooth that looks a bit different because of the size of the serrations, the angle of the crown, etc. I have compared it to all of my other tiger sharks and was able to come up with only one similar but smaller tooth. Both of these teeth oddly enough resemble each other in their overall shape and profile, coarse serrations along the mesial edge of the crown, etc. For comparison purposes, I inserted a "normal or common" looking aduncus type tiger shark tooth in between these two teeth in the one pic for comparison.

For the heck of it I also took a look at all of my G. cuvier teeth from Lee Creek, some 225 teeth in total with a great variety of positions, and none of them really resemble either of these two teeth from Calvert Cliffs.

So, it's possible that these two teeth are just anomalies and happen to be different from all of the otehrs I have found in 16 years of collecting. The larger of the two teeth in question is really an anomaly due to its sheer size, 1" long by 1" wide. It is much larger than my largest "aduncus" type tooth, and approaches the size of some G. cuvier teeth from Lee Creek.

Curious to know if anyone has any opinions about these two teeth, or have any similar in their collection.

Daryl.

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cowsharks

Thanks for the replies guys. I also stumbled upon another thread very similar to mine from a year ago started by FossilJunkie. The tooth in his pic is very similar to my large tooth.

http://www.thefossil...ttle-different/

If you read through the few replies there it seems the end conclusion was that his tooth was G. myumbensis.

Here's a combo pic of his tooth next to my tooth for comparison purposes:

post-2077-0-73797100-1327415312_thumb.jpg

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cowsharks

I'll also add that although Calvert Cliffs is Miocene, we do find teeth from other periods there; I have found Squalicorax kaupi (Cretaceous), Otodus (Eocene/Palaeocene), Cretalamna, Auriculatus, and a wicked nurse shark Nebrius obliquus. So, although no one is 100% sure where these teeth are coming from, we do find them there on occasion.

Daryl.

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Paleoc

G. mayumbensis is a rare but not singular find in the late Miocene of Florida. Here are some classic teeth from there:

Gmayumbensislingual_b.jpg

Gmayumbensislabial_b.jpg

Gmayumbensislabial2_600b-1.jpg

Gmayumbensislingual2_600b-1.jpg

Now these occur (as did your find) along with the more common tiger sharks (G. aduncus in your case) and with G. cuvier in the late Miocene of Florida. In North Carolina (and in your case) they are considerbly larger than their co-inhabitant, G. aduncus and stand out from them. I have never seen one from Lee Creek or certainly the Calvert formation. However, they appear to be the main constituant of the tiger shark fauna in the Miocene of Brazil. Here is a link to a PDF publication that shows a mixture of G. cuvier and G. mayumbensis in Brazil: http://scielo.iec.pa...4n3/v4n3a01.pdf Unlike more northernly occurances, the ratio (in the Miocene) is apparently higher for mayumbensis the further south towards the equator you go. This may be a tropical species, futher investigation is warrented.

Now the second question is: Is this a true species or a tooth varient of the more common tiger shark? I have seen over 100 tiger shark jaws, several thousand teeth and have not seen an equivalent tooth in G. cuvier. I posed the same question a couple of years back to a jaw dealer in Australia (who has had hundreds of tiger jaws pass through his hands) and he sent me a couple of tiger shark teeth he thought were close. They were slightly unusually shaped, but still clearly recognizable as G. cuvier and not G. mayumbensis. It is my belief due to the strongly arched root, weak distal notch, and size difference from G. aduncus that this may be derived from G. eaglesomi and of a separate (more tropical) linuage than the G. aduncus --> G. cuvier lineage. Now it would be interesting to see an assortment of modern jaws from say Brazil or other tropical Atlantic coastal region to see if this dentition crops up.

Edited by Paleoc

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Paleoc

Here is G. eaglesomi (Eocene) showing some of the same general features; strongly arched roots, large serrations, weak distal notch.

G_eaglesomi_sm.jpg

Edited by Paleoc

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Al Dente

I'll add a couple of photos of my own. Here's a Florida G. mayumbensis and a North Carolina version. Muller (1999) identified these as G. casei. I have seen an anterior tooth from the River Bend Formation that looked just like an eaglesomei except it had complex serrations.

post-2301-0-08904200-1327440973_thumb.jpg post-2301-0-79029000-1327440994_thumb.jpg

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cowsharks

Bill, should I conclude that my tooth is a G. mayumbensis from what you guys are saying? Or at the very least it is not Aduncus or Cuvier? From the pics you and Al Dente posted it looks like mayumbensis.

What about the smaller tooth on the far right in my original pics? It looks like a smaller version of the larger tooth.

Thanks a bunch to you guys for taking the time to reply with additional pics - it really helps to see more examples for comparison.

Daryl.

Edited by cowsharks

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siteseer
On 1/24/2012 at 2:47 PM, Paleoc said:

G. mayumbensis is a rare but not singular find in the late Miocene of Florida. Here are some classic teeth from there:

Gmayumbensislingual_b.jpg

Gmayumbensislabial_b.jpg

Gmayumbensislabial2_600b-1.jpg

Gmayumbensislingual2_600b-1.jpg

Now these occur (as did your find) along with the more common tiger sharks (G. aduncus in your case) and with G. cuvier in the late Miocene of Florida. In North Carolina (and in your case) they are considerbly larger than their co-inhabitant, G. aduncus and stand out from them. I have never seen one from Lee Creek or certainly the Calvert formation. However, they appear to be the main constituant of the tiger shark fauna in the Miocene of Brazil. Here is a link to a PDF publication that shows a mixture of G. cuvier and G. mayumbensis in Brazil: http://scielo.iec.pa...4n3/v4n3a01.pdf Unlike more northernly occurances, the ratio (in the Miocene) is apparently higher for mayumbensis the further south towards the equator you go. This may be a tropical species, futher investigation is warrented.

Now the second question is: Is this a true species or a tooth varient of the more common tiger shark? I have seen over 100 tiger shark jaws, several thousand teeth and have not seen an equivalent tooth in G. cuvier. I posed the same question a couple of years back to a jaw dealer in Australia (who has had hundreds of tiger jaws pass through his hands) and he sent me a couple of tiger shark teeth he thought were close. They were slightly unusually shaped, but still clearly recognizable as G. cuvier and not G. mayumbensis. It is my belief due to the strongly arched root, weak distal notch, and size difference from G. aduncus that this may be derived from G. eaglesomi and of a separate (more tropical) linuage than the G. aduncus --> G. cuvier lineage. Now it would be interesting to see an assortment of modern jaws from say Brazil or other tropical Atlantic coastal region to see if this dentition crops up.

 

Paleoc,

 

I have been researching mayumbensis for the past couple of days though I am on the road and away from my references at home.  I have not been able to confirm that it occurs in the late Miocene.  It is known from the Peace River and the phosphate mines in Florida but only from the lower part of the Bone Valley Formation according to a longtime collector of the Bone Valley.  He has also seen it from the Gainesville creeks (also noted by several members here with photos) which yield mostly Middle Miocene marine vertebrates and some younger land mammals.

 

If you have a reference listing a late Miocene site or have collected one, I'd like to hear about it.

 

Jess

 

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siteseer
On 1/24/2012 at 5:00 PM, cowsharks said:

Bill, should I conclude that my tooth is a G. mayumbensis from what you guys are saying? Or at the very least it is not Aduncus or Cuvier? From the pics you and Al Dente posted it looks like mayumbensis.

What about the smaller tooth on the far right in my original pics? It looks like a smaller version of the larger tooth.

Thanks a bunch to you guys for taking the time to reply with additional pics - it really helps to see more examples for comparison.

Daryl.

 

Daryl,

 

I would say that it is a G. mayumbensis.  Kent didn't list it in his Calvert Cliffs volume published last year but it appears your find is on a level of extreme rarity.  Elasmo.com has a frequency scale for teeth with the rarest teeth listed as what might be found by several people in a year but I believe there is a level of rarity beyond that.  It would be a tooth that one person might find one or two of in a lifetime and that's where I think you are with those two teeth.  The Calvert Cliffs yield teeth of Middle Miocene age so they aren't too old for mayumbensis and the occurrence that far north for a tropical shark is not without precedent.  There were likely unusually-warm summers in the Early-Middle Miocene just as there are today (and keep in mind that time was the second warmest in the Cenozoic Era - second only to the Early Eocene when there were crocodiles and palm trees on Ellesmere Island) so a tropical shark could have ranged farther north from time to time.

 

On my coast hammerhead sharks are known off Baja California but during unusually-warm summers they have been reported off San Diego.  It would not surprise me that in coming years they will be seen off Los Angeles and even Santa Barbara.

 

Jess

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siteseer
On 5/20/2019 at 11:34 PM, siteseer said:

 

,

 

 

 

 

 

 

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