Shark tooth ID help please

[Balance]

Going through my stuff while water continues to fall. Found this scooping a few weeks ago. Can’t place it with the usual suspects…

 

I thought it was a P. Contortus but it’s not quite there. If any of you shark experts recognize it I’d appreciate it. 

 

Thank you!

 

Jp
 

 

 

[Al Dente]

It might be Sphyrna mokarran tooth but I’m not sure. If not, it could be Carcharhinus. Maybe @MarcoSr knows.

[Balance]

@Al Dente it does appear to have the “hammerhead notch”. 
 

I found a thread that Marco Sr replied in about a similar tooth. I’ll await confirmation but it does seem to fit Sphyrna mokarran. 
 

Thank you!

 

Jp

[MarcoSr]

41 minutes ago, Al Dente said:

It might be Sphyrna mokarran tooth but I’m not sure. If not, it could be Carcharhinus. Maybe @MarcoSr knows.

 

I agree with Eric that your tooth could be a Sphyrna mokarran lower anterior tooth.  Below are pictures of lower anterior teeth from one of my extant Sphyrna mokarran jaws and a loose extant lower anterior tooth.  These teeth look very similar to your tooth.

 

 a1L

 

 

a1R

 

 

a2L

 

 

a2R

 

 

and a loose lower anterior tooth (18mm)

 

 

 

 

Marco Sr.

[digit]

3 hours ago, Balance said:

it does appear to have the “hammerhead notch”. 

I'm not really seeing the "notch" which is said to be characteristic of this genus but then there is Marco's thread which has some wonderful images from a modern jaw.

 

https://www.fossilguy.com/gallery/vert/fish-shark/sphyrna/sphyrna.htm

 

 

If I'd seen this tooth and was asked to classify it I'd have said Carcharhinus sp. without much thought and moved on. That being said, I've likely misidentified lots of Sphyrna teeth over the years. The only one I can identify with any conviction is Sphyrna tiburo (the Bonnethead Shark) the smallest of the genus. They have very characteristic lower anterior teeth and crushing teeth for posteriors (they have a diverse diet including lots of invertebrates). The upper anterior teeth of this species resemble Rhizoprionodon teeth and I still have problems separating those two taxa.

 

 

Cheers.

 

-Ken

 

[Balance]

@MarcoSr Thank you! Really appreciate the visuals. - in the second photo the jaw appears to have some “tile work” behind done. What’s that cool texture called?

 

@digit If you held it you’d see it’s different. I had  it in with the bulls too. It stands out as different extremely clearly in a pile of bulls though. That super robust root mass and the bulbous structure from center are different. 
 

Will put this one with the specials and out of the general collection area. Thanks everyone!! 
 

Jp
 

 

Edited November 12 by Balance

[MarcoSr]

2 hours ago, Balance said:

@MarcoSr Thank you! Really appreciate the visuals. - in the second photo the jaw appears to have some “tile work” behind done. What’s that cool texture called?

Jp
 

 

 

Shark cartilage.

 

Marco Sr.

[Jaybot]

Marco, those shark jaws of yours are such a valuable tooth ID'ing tool.  Thank you for sharing!

 

Nice hammerhead JP!

[Shellseeker]

Hmmm,

@Balanceshowed me this tooth and asked my opinion.  Over the last 15 years I have found tens of thousands of shark teeth. How rare is this in SW Florida? I could not identify it. Looked like a small GW, but I could see it was not.  Once again , Why so rare?

[Shellseeker]

I just looked at a "for sale" shark teeth site for Hammerhead sharks... None of them were Sphyrna mokarran.  All of them were other species and were the 1/2 inch size that I do commonly find in the Peace River...

So, @digitand @BalanceYou have hunted Bone Valley Rivers and Streams. How many of these Sphyrna mokarran teeth have you found ?

[Balance]

@Shellseeker

 

Having just gone through all of my teeth for that AI photo project I don’t recall any. Now, I have all my P. Contortus in a separate area so I’m going to look through them because if I have any they will be miss ID’d with as a small P.c because of that tiny twist and substantial root size. 
 

I’ll update later this evening. 
 

Jp

[Balance]

@Shellseeker I don’t see a single other one like this. 
 

@digit I apologize, I confused the notch with the deep nutrient groove. 
 

As to the rarity I can only speculate a couple ideas from the basic research today. 
 

1: They are lone apex hunters. Not schooling hammerheads. So isolated… 

2: The modern species is known to migrate north in the summer. Considering the Pliocene and Miocene we’re really hot I wonder if the territory of great hammerheads was further north. 
 

Best I got so far. Time for Cub Scouts… 

 

Jp

[Shellseeker]

26 minutes ago, Balance said:

@Shellseeker I don’t see a single other one like this. 
 

@digit I apologize, I confused the notch with the deep nutrient groove. 
 

As to the rarity I can only speculate a couple ideas from the basic research today. 
 

1: They are lone apex hunters. Not schooling hammerheads. So isolated… 

2: The modern species is known to migrate north in the summer. Considering the Pliocene and Miocene we’re really hot I wonder if the territory of great hammerheads was further north. 

Best I got so far. Time for Cub Scouts… 

Jp

1st I was after the point that teeth of the Giant Hammerhead (for shark that has existed for 20-40 mya) could be as common as Mako, GWs, Megs, etc etc... but if many/most of SW Florida Hunters say they have not found it... then with serrations , it is beyond rare. 

 

You jumped right to step #2... which is the WHY ? Thanks for the reply and insights.

I saw a data point that there may be less than 200 Giant Hammerheads in the world.. On the Endangered list... 

 

I am copying your photos to my local disk....