Help Identify Found on Manasota Key

[ruger11]

I'm not sure what this is. It was found on Englewood beach and a found a similar one father north on the key.

[Peat Burns]

Looks like a broken shark tooth. Possibly megaladon 

[Coco]

Hi,

 

Or Isurus.

 

Coco

[digit]

Agreed. It's a worn fragment of one of the larger shark teeth that we find here in Florida. Difficult to see from just photos and you may be able to make out more detail with the specimen in hand. Take a look at the edge of the tooth and see if you can spot indications of serrations. The tooth is pretty worn and tumbled and it looks like the edge may be well worn but if you can spot any signs of serration while looking at the tooth under magnification with bright light, then that would tend to indicate a megalodon tooth. If the edge looks completely smooth with no sign of (former) serrations, it may possibly be from a shark we used to call a "mako" but due to more recent taxonomic changes it is now thought to be an ancestor of the Great White Shark (Carcharodon carcharias) and so we are trying to use the common name "white shark" tooth instead of "mako" tooth (but we often slip into old habits and still tend to call them "makos").

 

https://www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/carcharodon-hastalis

 

This species has long been known as Isurus hastalis (as Coco mentioned) and you will still find many references to it as Cosmopolitodus hastalis (still as a "mako") but more recently it is considered to be Carcharodon hastalis. You can imagine that it is very difficult to construct evolutionary family lineages from ancient shark species when all you have are teeth and sometimes a few vertebrae (cartilaginous skeletons are largely not found in the fossil record other than exceptional preservation circumstances). It is entirely likely that new research may one day find these back in the group with mako sharks but for now the large unserrated teeth are being called "white shark teeth"--ancestors of the most famous movie shark (though megalodon sharks are gaining popularity due to recent cheesy movies and pseudo-documentary shows on TV).

 

Welcome to the forum! You are well positioned in Florida to find some even better examples of fossilized shark teeth and are neighbors with @jcbshark.

 

 

Cheers.

 

-Ken

[jcbshark]

Definitely looks to be a mako or meg frag