Plesiosaur tooth from Stary Oskol, Russia

[msantix]

Hi,

 

Saw this tooth recently, it is from Stary Oskol in Russia and is just 23mm in length. Listed as an Elasmosaur and the size and curve seem right for the id, but the striations almost appear more Pliosaur like (some terminate halfway up the tooth especially in pics 2 &3). Does anyone know what type of Plesiosaur tooth this could be?

 

Thanks!

 

[Jaybot]

Cool looking tooth.  Unfortunately I can't help, but others can

@pachy-pleuro-whatnot-odon @North

[FF7_Yuffie]

I have one very similar to this which was ID'd (cant remember if here or a Facebook group) as being a Elsamosaurus tooth.

[pachy-pleuro-whatnot-odon]

Vendors indeed generally identify these as elasmosaur, and so collectors have started copying this identification. However, I'm unaware of any skeletal material having been found in direct association with these teeth. And in absence thereof, I'd agree that the striae are unlike those anastomosing ridglets you'd expect to see on an elasmosaur tooth, nor are these teeth sufficiently laterally compressed. So, no, these aren't elasmosaur teeth...

 

The striae indeed look very similar to those of pliosaurs, however the teeth are not quite robust enough from the brachauchenine pliosaurs that would've been around at the time. Which leaves them to be polycotylid - though I'm yet to figure out what genus or species...

[jpc]

I can't help with ID but I can say nice job on the photos.  We can actually see the features you mentioned.  

 

 

[pachy-pleuro-whatnot-odon]

17 hours ago, jpc said:

I can't help with ID but I can say nice job on the photos.  We can actually see the features you mentioned.  

 

Those are actually the vendor's photographs... 🤫 But, yeah, he does take quality photographs of the pieces he sells. Not always as easy to do...

[Psittacosaurus]

On 11/8/2024 at 6:33 AM, pachy-pleuro-whatnot-odon said:

Vendors indeed generally identify these as elasmosaur, and so collectors have started copying this identification. However, I'm unaware of any skeletal material having been found in direct association with these teeth. And in absence thereof, I'd agree that the striae are unlike those anastomosing ridglets you'd expect to see on an elasmosaur tooth, nor are these teeth sufficiently laterally compressed. So, no, these aren't elasmosaur teeth...

 

The striae indeed look very similar to those of pliosaurs, however the teeth are not quite robust enough from the brachauchenine pliosaurs that would've been around at the time. Which leaves them to be polycotylid - though I'm yet to figure out what genus or species...

Is Cryptoclidus sp. a good candidate? 

[pachy-pleuro-whatnot-odon]

15 hours ago, Psittacosaurus said:

Is Cryptoclidus sp. a good candidate? 

 

Strictly speaking about Cryptoclidus sp., no, as that species was already extinct at the time. If you expand it to "cryptoclidia indet." we end up in confusing territory, and I would say it's possible. That's because it all depends on what phylogeny you support. Take a look at the below figure (figure 5) from Benson et al. (2012).

 

 

What we're dealing with is essentially what I'd consider a polycotylid tooth, so a member of the polycotylidae. Benson et al. (ibid.) reconstruct their phylogeny as belonging to the leptocleidia-clade, which is a sister-grouping to cryptoclididae and a member of crytoclidia. So, in that case, saying that the tooth is "cryptoclidia indet." would be possible if you'd like a catch-all that includes both polycotylids and elasmosaurs. However, it's carrying the branch back quite a bit to the point where it'd be rather similar to stating "it's a plesiosaur tooth".

 

Moreover, this is the only phylogeny - albeit my preferred one - that supports polycotylids and cryptoclidids belonging to the same branch. For, as can be seen in the foreshortened phylogenies below the main diagram, other others have variably reconstructed polycotylidae and cryptoclididae as sister taxons (as Benson et al. [ibid.] do) but to the exclusion of elasmosauridae; or have grouped polycotylidae not with plesiosauroidae, but with pliosauroidae on a completely different stem-branch.

 

In the end, it's all up to what you believe to be the most reliable phylogenetic reconstruction - something that's notoriously difficult with plesiosaurs - but not necessarily wrong either.