Shark Teeth - Otodus, Cretalamna, Archaeolamna, Serratolamna or......??

[Gareth_]

Hey all

Shark teeth confuse me.... it seems the more I know, the less I know!

The small rock and fossil shops I visit (when I can get near them - no shops near home) often sell shark teeth labeled Otodus (O. obliquus, these shops usually just give the Family name - Mosasaur, Spinosaur, Otodus etc). This is the only shark tooth I've been commonly exposed to "in the flesh". I've done a bit of digging on the net and now I'm not sure all teeth I have seen (and purchased) are Otodus - which is fine with me, I just like to be accurate.

I have one which I was told is Cretalamna, it definitely looks different to the other teeth (the root is a lot flatter). A lot look like what I believe is O. obliquus but...... are they?!

Is it possible to definitively tell the difference, especially without a find location? I assume, once they start to get larger it rules most/all but O. obliquus out? I'm just not experienced enough to spot the nuances between the genera and most of these are small. 

The two other genera I've noticed (and of course, there will likely be some more) are Serratolamna and Archaeolamna.

 

In the pic with 5 teeth, I would say top left is Otodus, top right is Cretalamna, but all of the smaller teeth in that group and the teeth in the other pics are....?

Any help is appreciated!

Also, sorry about the not fantastic pics, they're taken on my aging phone. DSLR is too hard to get out

Sorry there is no scale on the last 2 pics, I took that a few days back and those pics didn't need a scale - they are all a similar size to the bottom  3 teeth on the first pics

 

[Gareth_]

There must be some shark tooth experts on here   I've found it is hard to come across good information on O. obliquus on the web 

I have another one, Otodus I assume but the cusplets are a little different to what I'm used to. They're almost starting to split into two. Mild pathology? Transitional species and a start to serrations? 

 

 

 

[ThePhysicist]

On 8/5/2021 at 7:40 AM, Gareth_ said:

it seems the more I know, the less I know!

Hang on, the Dunning-Kruger curve is a steep slope down .

 

In the first image, left is Otodus obliquus, right is Cretolamna biauriculata. C. biauriculata tends to be wider, with broad cusplets, often multiple pairs. The central cusp is also broad and flat. As for the three smaller teeth below those, I believe the middle (??) and rightmost are Otodus, the leftmost is odd - I don't know what it is. @Praefectus@Al Dente@MarcoSr@siteseer

 

In the array of smaller teeth, the circled tooth is Cretolamna appendiculata (anterior) - note the narrow crown with both edges concave, and the squared-off ends of the root lobes. Otodus and Cretolamna lateral teeth can be tough to differentiate, but I'm almost sure the rest are Otodus (maybe). Then again, I'm still not great with Moroccan teeth. This thread may be of use. @Harry Pristis

 

 

On 8/7/2021 at 7:33 AM, Gareth_ said:

Mild pathology?

Yes. 

 

This also appears to be a handy reference for Moroccan shark teeth: http://users.telenet.be/sharkteethcollection/sharkteeth list totaal/totaal sharteeth list.htm

Edited August 15, 2021 by ThePhysicist

[bthemoose]

33 minutes ago, ThePhysicist said:

I believe the middle (??) and rightmost are Otodus, the leftmost is odd - I don't know what it is.

I would call that one an Otodus too, but a more posterior tooth.

[Gareth_]

@ThePhysicist @bthemoose thank you both for your input. I admit, I had to look up the Dunning-Kruger curve but wow is it true haha.

The tooth you circled in red I did wonder about, it is a little different, the little tip you mentioned about the root lobes does help, especially if I come across more of them. This tooth in particular is razor sharp!

Yep you confirmed my suspicion about the larger one (top right of the pic of 5) being a Cretalamna tooth. It's really cool to have a number of teeth from the Odontidae family!

If you're any good at the younger end of the Odontidae family, please check out the thread I posted yesterday.... call it a "name that species challenge"