Shark Teeth Serrations

[minnbuckeye]

Now don't laugh at me too much for my question!! I just stumbled onto a post asking for an ID of what they thought was a lemon shark and it brought up a question I have had for a long time:

  

                     10 hours ago, hemipristis said:

Lower Carcharhinus, imho

            I usually only go with lower Carcharhinus when I see serrations on the blade, but maybe they are worn off. Also I can’t see it under a      microscope. 

 

I have the chance to collect shark's teeth once a year and consider myself an absolute novice at ID.  My question to the forum is how do you tell if a tooth is serrated? Silly question on a big meg. But on the smaller teeth, I often find a tooth that I run my finger nail down the edge and can feel "bumps". It is not smooth. Yet I can't say I really see serrations. How would you classify this???? 

 

Mike

[Al Dente]

5 minutes ago, minnbuckeye said:

Now don't laugh at me too much for my question!! I just stumbled onto a post asking for an ID of what they thought was a lemon shark and it brought up a question I have had for a long time:

  

                     10 hours ago, hemipristis said:

Lower Carcharhinus, imho

            I usually only go with lower Carcharhinus when I see serrations on the blade, but maybe they are worn off. Also I can’t see it under a      microscope. 

 

I have the chance to collect shark's teeth once a year and consider myself an absolute novice at ID.  My question to the forum is how do you tell if a tooth is serrated? Silly question on a big meg. But on the smaller teeth, I often find a tooth that I run my finger nail down the edge and can feel "bumps". It is not smooth. Yet I can't say I really see serrations. How would you classify this???? 

 

Mike

 

I always look at teeth under a microscope to see if serrations are present. The fingernail test can fail you if the blade has tiny chips in the enamel or if the serrations are worn off. When serrations are worn off, you can usually see where the serrations were under magnification, there is usually a color change on the blade between where the serrations were.

[minnbuckeye]

Thanks @Al Dente. I don't have a scope. To clarify a little better, if I do feel but do not see serrations and think the roughness is real, is it better to assume serrations? Or is this VERY inaccurate? 

 

Mike

[Searcher78]

Which ones are lemons?

[Searcher78]

Under a microscope.

[Al Dente]

12 minutes ago, Searcher78 said:

Which ones are lemons?

I think they are all Carcharhinus.

[Searcher78]

25 minutes ago, Al Dente said:

I think they are all Carcharhinus.

Why?

 

[Notidanodon]

I would have said the bottom one is almost surely lemon based on the root shape and the 2nd last one is likely lemon, but more carcharinus like, but then again im usually wrong lol

@Al Dente how did you come to that decision? thanks  

[Al Dente]

Here’s a modern Negaprion tooth set from the j-elasmo website http://naka.na.coocan.jp/

Most of the teeth have a main cusp longer than the tooth is wide. The upper teeth have notches on either side of the main cusp. The lower posterior teeth that resemble Carcharhinus teeth have a long enamel shoulder.

 

 

[digit]

A concise reply to a vexing question that plagues all of us where Negaprion and Carcharhinus teeth are quite common.

 

 

Cheers.

 

-Ken

[Troodon]

I book that I have used often in my early days of collecting was Kent's Fossil Sharks of the Chesapeake Bay region.region.   Pretty encompassing.

 

 

[digit]

I just picked up a used copy of this book which has been out of print for decades. They are now going for 10X to 20X their original list price.

 

First copy I found for a (relatively) lower price got lost in the post office during COVID delays. I sent a 2-day delivery box that took a month to be received at the time so I gave this quite some time before reporting it MIA. Can't believe they shipped and expensive book without tracking but I was refunded and a few months later located another copy that was nearly as cheap. Working my way through a little at a time trying to digest the distinctive features enumerated in that tome.

 

Nice book if you can locate one that doesn't require a mortgage.

 

 

Cheers.

 

-Ken

[Troodon]

Yep pretty hard to obtain, glad I have one.  They need another printing 

[Searcher78]

Well, I have something to do this weekend. Go through all my Carcharhinus and lemon teeth and try to decide what is lemon.

[minnbuckeye]

@Searcher78, maybe I didn't ask such a silly question!!! I will wait until winter to go through mine.

 

 Mike

[hemipristis]

3 hours ago, Searcher78 said:

Which ones are lemons?

The citrus-flavored ones.

 

jk. I’ll provide a serious reply tonight 

[minnbuckeye]

9 hours ago, hemipristis said:

The citrus-flavored ones.

 

Finally the truth!!!!!!!!!!!!!