Gainesville Shark Teeth Question

[ClearLake]

I have three teeth that were picked from matrix out of a creek in Gainesville Florida (thanks Ken, @digit).  Fossils from here are generally Miocene (Hawthorn Fm) in age.  The scale bar at the bottom is 1 cm per color division.   I readily admit to being terrible at shark tooth ID; the dizzying array of variability and overlap is just too much for this old brain I guess .  I have the Florida Paleontological Society publication (Boyd, 2016), a couple other books and have spent a bunch of time at elasmo.com, but these three teeth have me questioning myself.  At first blush, I want to call them some species of Carcharhinus, but then I don't see a good nutrient groove (maybe just eroded away?).  They are more triangular then the dozens of other Carcharhinus specimens I have from this site but the serrations and roots (what's left of them) look similar.  Appreciate any help because I'm just going in circles.

 

     

 

 

    

[Al Dente]

All three are Carcharhinus. You can see a faint nutrient groove on the left and right specimens. 

[ClearLake]

11 minutes ago, Al Dente said:

All three are Carcharhinus. You can see a faint nutrient groove on the left and right specimens.

Thanks.  I think my brain just didn't want to admit it - haha  I'm not sure I'm even going to try to go down the species route, seems that is just too ambiguous on these isolated teeth.

[digit]

Yup. Isolated carcharhinids need to be just about perfectly preserved and then I believe only a couple of the more distinctive species in that genus can be positively identified. There is just too much variation within a species due to tooth position and ontological changes. The more I try to talk myself into a species-level ID in this genus the more I question my knowledge of shark teeth.

 

Glad you found some interesting shark & ray teeth in the matrix. Hoping you got some nice Ginglymostoma and some interesting wee tiny teeth.

 

 

Cheers.

 

-Ken

[ClearLake]

3 hours ago, digit said:

Hoping you got some nice Ginglymostoma and some interesting wee tiny teeth

I have one so far, but it is a bit broken, still pretty neat though.  Yes some awesome tiny teeth, and plenty more matrix to go through yet!  I will be posting so more on this in the near future, both ID questions and some fun data (at least to me).  Thanks

[ClearLake]

OK, you were very helpful on the first set of teeth so I have a few more to confirm or correct my ID on.  I appreciate the help.

 

I have numerous Hemipristis serra from the matrix, both uppers and lowers and most of them I am fairly certain on.  Below is one that I am less certain, but believe to be a Lower Posterior tooth of H. serra due to the shape, very thick root, and how the enamel comes down a ways onto the root (upper right picture below).  See pictures below:

 

I also have a group of teeth (see below) that have a similar thick root and bend to the crown but have a slant to the crown and a different looking enamel pattern.  Are these something else or just a different form to the tooth above?  I didn't take a set of pictures from the other side, but the enamel ends in a straight line all around the tooth.

 

 

The next set of teeth, which are quite common, I am calling Negaprion brevirostris.  Please let me know if this is not correct.  Thanks

 

 

I have a few more I will post a bit later on. Thanks for your help.

[ClearLake]

In the matrix I have picked these fossils from, teeth of Carcharhinus are the most common genus and most of them I am happy to leave at that.  But this next group are distinctive enough that I believe I can pin down to Carcharhinus signatus.  Is this correct @Al Dente, @digit @FossilDAWG @siteseer or anyone else that cares to opine??  I have primarily used Boyd (2016) for this ID.  Even if the ID is not correct, there are some pretty little teeth in this group.

 

 

The teeth that are most similar to the ones above are these that I believe are Galeocerdo based on the more arched profile of the teeth as opposed to the straight slant of the ones above.  Is this correct?  Again, some neat teeth in here, especially that yellow one.

 

 

Lastly (for now) I have one ray tooth that is very distinctive but that I can't seem to find in the usual references that work for this location.  I found a picture on J-elasmo (http://naka.na.coocan.jp/Batomorphyc.html) that looks fairly similar (Burnhamia woodwardi) but it was for a tooth from the Eocene of Kazakhstan and a brief search did not locate any references for that genus on this side of the world so I am open to any suggestions.

 

 

Thank for any assistance that can be offered!

 

Mike

[Shellseeker]

50 minutes ago, ClearLake said:

The teeth that are most similar to the ones above are these that I believe are Galeocerdo based on the more arched profile of the teeth as opposed to the straight slant of the ones above.  Is this correct?  Again, some neat teeth in here, especially that yellow one.

A while back,  I found a Symphyseal similar to your yellow tooth..

 

[Al Dente]

1 hour ago, ClearLake said:

Lastly (for now) I have one ray tooth that is very distinctive but that I can't seem to find in the usual references that work for this location.  I found a picture on J-elasmo (http://naka.na.coocan.jp/Batomorphyc.html) that looks fairly similar (Burnhamia woodwardi) but it was for a tooth from the Eocene of Kazakhstan and a brief search did not locate any references for that genus on this side of the world so I am open to any suggestions.

 

This last tooth is the lateral tooth of a ray tooth plate. Here is an example from the elasmo.com website.

 

 

[Al Dente]

1 hour ago, ClearLake said:

The teeth that are most similar to the ones above are these that I believe are Galeocerdo based on the more arched profile of the teeth as opposed to the straight slant of the ones above.  Is this correct?  Again, some neat teeth in here, especially that yellow one.

Do these 4 teeth that you have labeled as Galeocerdo have serrations that go to the tip or almost to the tip? If you use Boyd’s book as a guide, these look more like his C. signatus than they do to Galeocerdo. Take a look at his Galeocerdo photos and notice the root shape and main cusp thickness and shape. They are a bit different than the signatus. I think all 4 of these teeth match the signatus better than Galeocerdo teeth.

 

 

[ClearLake]

4 hours ago, Shellseeker said:

A while back,  I found a Symphyseal similar to your yellow tooth.

Thanks for the link, that was an interesting thread to read.  Highlights a fair amount of confusion and uncertainty, but there are lots of nice examples in there.

[ClearLake]

4 hours ago, Al Dente said:

This last tooth is the lateral tooth of a ray tooth plate. Here is an example from the elasmo.com website

Yes, I was trying to figure out which ray.  Thanks for directing me again to elasmo.com as I looked closer this time and sure enough they describe Burnhamia and I can clearly see that mine is not that (no depression in the occlusal face).  My problem with this plate is I picked hundreds of ray samples and found lots of Aetobatus, Myliobatis, and Rhinoptera, but this one looks different from all those.  In looking at the diagram you sent of Pteromylaeus and reading through their descriptions and pictures of it, I think that is a reasonable fit considering everything.  Only feature I can't see are the foramina they discuss even though mine is pretty well preserved.  Thanks for the input.

[ClearLake]

4 hours ago, Al Dente said:

Do these 4 teeth that you have labeled as Galeocerdo have serrations that go to the tip or almost to the tip? If you use Boyd’s book as a guide, these look more like his C. signatus than they do to Galeocerdo. Take a look at his Galeocerdo photos and notice the root shape and main cusp thickness and shape. They are a bit different than the signatus. I think all 4 of these teeth match the signatus better than Galeocerdo teeth

Thanks, excellent points.  That's one of my problems with sharks teeth, I'm not always familiar enough with the differences to know which features are the most important.  I was so focused on the slightly arched shape of the main cusp that I totally missed the lack of fine serrations on the main cusp of those four teeth.  Back in with the other C. signatus they go!!  Thanks