Tooth Identification

[Miocene_Mason]

17 minutes ago, Auspex said:

C. auriculatus (assigned a different genus)

The latest revisions (I believe that’s the right paper) place the whole Megalodon lineage into Otodus. auriculatus differs from angustidens by more than simply serrations, also some blade and cusp differences though @MarcoSr has said that age is the only definite indicator.

 

7 hours ago, Gizmo said:

I'm curious as to how many specimens in this lineage you've examined to base your statement on.

Being honest, not an incredible amount. In my hands, one aksauticus and two auriculatus. I have looked at pictures and descriptions online as well. If you have any information to the contrary, I’d love to hear it (I’m always up for learning something!) 

[MarcoSr]

The tooth is an Otodus aksuaticus from the Eocene, Woodstock Member of the Nanjemoy Formation.  Look at the partial serrations.  Otodus obliquus is not serrated.  Otodus auriculatus is fully serrated.  A good number of researchers including Cappetta now put the entire lineage from obliquus to megalodon in the Otodus genus.  There is variation in serrations, cusplet features, crown and root features etc. within the different species themselves and overlap of these features between the different species that can make distinguishing the species of an individual tooth almost impossible.  Age of the formation is a very good indicator of the species.  I've held many thousands of teeth from the Otodus lineage in my hand and can't distinguish for sure the species of a good number of them.  Trying to distinguish a species from a couple of grainy pictures on TFF isn't much better than guesswork unless the tooth has classic species features like the tooth in this post.  Plus it helps to have collected the site it was found at for 40+ years.

 

Marco Sr.

[Gizmo]

2 hours ago, Auspex said:

Is that name valid now for specimens from outside of Africa?

The lineage was  moved to Otodus recently.

[Auspex]

1 hour ago, MarcoSr said:

A good number of researchers including Cappetta now put the entire lineage from obliquus to megalodon in the Otodus genus. 

Well, there you go!

I am way behind the curve on taxonomic realignments among the elasmobranchs...
Sorry to have perpetuated out of date information!

[Calvert Cliff Dweller]

Thanks again to all the Folks on TFF for helping identify this rare transitional tooth. 

[Kimi64]

On 4/25/2018 at 3:51 PM, Calvert Cliff Dweller said:

Reverse pic

I hunt all over Southern Maryland, not Just Brownies, so thanks for sharing.