The mystery tooth revealed.

This is a dive trip in the Edisto from last month when the waters were much warmer. I found a lot of cool fossils on this dive. I remember fanning out what I thought was a small posterior angustidens at first. Upon closer inspection when I got home I realized that the tooth was not a posterior angustidens shark tooth.What could it be?

Then after looking it over I came to the conclusion that it was a very rare thresher shark tooth with side cusps!  I showed it to DW to confirm the proper id and he agreed also. I love this hobby!