What kind of teeth are these? Found in Virginia

[FreshWaterSharK]

[caldigger]

I'll try.

Starting with the orange one and going clockwise.

-Otodus megalodon

-Otodus auriculatus

-O. auriculatus

-O. auriculatus

-O. megalodon for the smaller one.

I'm sure I'll probably be corrected, but that's my guess based on the examples I have.

[Praefectus]

2 minutes ago, caldigger said:

I'll try.

Starting with the orange one and going clockwise.

-Carcharodon megalodon

-Carcharocles auriculatus

-C. auriculatus

-C. auriculatus

-C. megalodon

I'm sure I'll be corrected, but that's my guess.

I agree with the species IDs. @caldigger You are using both carcharodon and carcharocles to describe the mega toothed sharks?

 

I believe the currently accepted genus for the whole family is Otodus.

 

Starting from orange: 

Otodus megalodon

Otodus auriculatus

Otodus auriculatus

Otodus angustidens

Otodus megalodon

 

 

 

 

 

[caldigger]

Sorry, just reading off labels. A bit "old school" I guess. I'll correct.

Kindly excuse my ignorance, but please enlighten me and anyone else reading this why the fourth one is

O. angustidens over the auriculatus.

They looked the same to me. 

[Praefectus]

20 minutes ago, caldigger said:

Sorry, just reading off labels. A bit "old school" I guess. I'll correct.

Kindly excuse my ignorance, but please enlighten me and anyone else reading this why the fourth one is

O. angustidens over the auriculatus.

They looked the same to me. 

 

I miss the "old school." I still refer to C. hastalis as giant makos. All the name debates are too difficult to keep up with. 

 

I could be wrong, but I made the judgement on 4 based off the cusp. The cusps on O. angustidens protrude less than those on O. auriculatus. Now that I'm looking at it closer, I think 3 might also be O. angustidens. I can't tell if 3 has a double cusp or if it has been damaged and the cusp got nicked. 

 

[caldigger]

I think some better focused pictures with improved lighting may be in order.

They're kinda dark to see good details.

 

Since I don't see these teeth on this side of the States, my familiarity is a bit lacking.  Thanks for your insights.

[Praefectus]

I agree. Some more pictures would be helpful. 

 

I'm still not entirely sure how to differentiate between angys and rics. It seems like every expert uses a different formula. Below is how I tell them apart. If anyone has a better method, I'm all ears. 

 

O. otodus - Unserrated.

O. mugodzharicus - Early serrations. Appear as very fine folds, "waves."

O. aksuaticus - Serrations at the base of the crown and on the lateral cusps. 

O. auriculatus - Serrations that almost reach the tip (2/3 serrated crown).

*O. poseidoni - First fully serrated tooth.

O. sokolovi - Wider crown, flatter root.

O. angustidens - Wider crown, smaller cusps.

O. chubutensis - Cusps disappearing into crown.

O. megalodon - No cusps. 

 

*Synonymous with auriculatus??? 

[Troodon]

Check out the elasmo site.  

 

[MarcoSr]

I have seen and held in my hand thousands of teeth from the Otodus lineage in my collection and in the collections of my two sons.  I can tell you with 100% certainty that the tooth feature guidelines given by the researchers for the different Otodus lineage species are totally inadequate to id a good number of teeth with certainty.  These teeth features vary tremendously within each species and there is a lot of overlap (which is totally expected in crono species) of tooth features among the different Otodus species.  I can accept feature differences like the following to differentiate Otodus lineage species:

 

 

Does the tooth have Cusplets?  Yes? No?  Even this criteria can cause questions when crown bulges by the root are considered vestiges of a cusplet.

 

Is the tooth partially serrated?  Yes?  No?  This criteria can cause questions when a tooth has wavy cutting edges which are considered the beginnings of serrations.

 

Is the tooth crown fully serrated?  Yes? No?  I have teeth where this even comes into question where I can’t see a tip serration or it looks like the very tip may not be serrated.

 

Criteria like ragged serrations, coarse serrations, fine serrations etc. are way too subjective and there is too much tooth feature variation in this area.  Crowns being narrow, broad, wide etc. there is again too much subjectivity and too much variation.

 

 

So unfortunately because of the tremendous variation of teeth features in each species in the Otodus lineage and the large amount of overlap of these tooth features among the different species one of the best criteria for the id of a Otodus lineage tooth is the age of the formation that the tooth came from.  So any id, especially Auriculatus through Chubutensis, could be questioned if the age of the formation that the tooth came from is not known.

 

 

Edit:  I should have mentioned that I worked with a small group of analysts who created computer algorithms to try to id teeth in the Otodus lineage from high definition indexed photographs taking measurements and using concrete criteria like serrations per inch, serration ratios (like height/width), serration form (separate forms like square, rounded, oval tops),a  multitude of different tooth measurement ratios ( using measurements like crown width at different points, crown slant height, crown vertical height, crown angles from perpendicular , root lobe measurements and ratios, separate root lobe shapes etc.).  I helped determine the feature measurement parameters that I thought might be the most diagnostic, and the analysts turned them into computer algorithms that measured, calculated and captured tooth metadata from the tooth pictures.  We made plots of different metadata for the teeth samples.  What we saw, although there was clustering of some metadata, was a tremendous variation in tooth features and lots of overlap among different species.

 

Marco Sr.

[SailingAlongToo]

Some info on the general location(s) where they were found and known strata  / geology for the area(s) would definitely be helpful in making IDs. If the geology isn't known for the area(s) in question, given these are stated to have come from VA, general location(s) where found is all many folks on TFF need to help with definitive IDs.  I'm guessing they came from a shoreline of a river / stream, below some cliffs or bluffs in the ENE part of VA.