Oxford Clay croc tooth?

[Notidanodon]

Hi guys, I have this tooth from the Oxford clay and i was wondering if anyone could put a solid ID on it   thanks 

[pachy-pleuro-whatnot-odon]

What I can tell you is that it's either a plesiosaur or crocodile tooth. If plesiosaur, it'd be Tricleidus seeleyi, whereas if it's a marine crocodile, it'd probably be classed as Steneosaurus sp.. The latter genus, however, has had many of its species re-assigned to different genera in recent year (see here), so that teleosauridae indet. would be the more proper counterpart, unless the specific species can be established. Below is a sample of 'Steneosaurus' teeth and minimal descriptions, taken from Mueller-Töwe (2006) (for a more extensive discussion, see @abyssunder's post):

 

 

I'm, however, not sure whether this is a crocodile tooth, and my first hunch is that it may be Tricleidus seeleyi, based on the cross-section through the teeth, the variability in thickness of the striations, absence of clear evidence for carinae where the minor striae could converge. In order to properly establish that, though, I'd need to get a much better feel for the tooth's striations, see if it has carinae, apicobasal ridges, etc., which is very difficult from photographs, as basically, you'd need to reconstruct a full three-dimensional mental image of the tooth. In that respect, the below discussion may be of interest:

 

 

Edited February 17, 2022 by pachy-pleuro-whatnot-odon

[Notidanodon]

9 hours ago, pachy-pleuro-whatnot-odon said:

What I can tell you is that it's either a plesiosaur or crocodile tooth. If plesiosaur, it'd be Tricleidus seeleyi, whereas if it's a marine crocodile, it'd probably be classed as Steneosaurus sp.. The latter genus, however, has had many of its species re-assigned to different genera in recent year (see here), so that teleosauridae indet. would be the more proper counterpart, unless the specific species can be established. Below is a sample of 'Steneosaurus' teeth and minimal descriptions, taken from Mueller-Töwe (2006) (for a more extensive discussion, see @abyssunder's post):

 

 

I'm, however, not sure whether this is a crocodile tooth, and my first hunch is that it may be Tricleidus seeleyi, based on the cross-section through the teeth, the variability in thickness of the striations, absence of clear evidence for carinae where the minor striae could converge. In order to properly establish that, though, I'd need to get a much better feel for the tooth's striations, see if it has carinae, apicobasal ridges, etc., which is very difficult from photographs, as basically, you'd need to reconstruct a full three-dimensional mental image of the tooth. In that respect, the below discussion may be of interest:

 

 

Thanks once again for your help  someone thought metriorhynchus was a possibility. I will see if I can get some better close ups of the striations when I get home on Monday  

[Ossicle]

Fantastic tooth!

 

It looks more similar to my plesiosaur tooth than my crocodile teeth from the Oxford Clay, but that's a very superficial similarity and nothing I have is quite this shape. It's a very distinctive, interesting tooth.

 

Clearly from what has been posted crocodile teeth are more varied than I understood, so it could be, but it looks more plesiosaur to me.

 

 

 

 

[pachy-pleuro-whatnot-odon]

8 minutes ago, Ossicle said:

It looks more similar to my plesiosaur tooth than my crocodile teeth from the Oxford Clay, but that's a very superficial similarity and nothing I have is quite this shape. It's a very distinctive, interesting tooth.

 

Clearly from what has been posted crocodile teeth are more varied than I understood, so it could be, but it looks more plesiosaur to me.

 

Unfortunately, you often see a lot of crocodile teeth misidentified as plesiosaur. Thing is, though, that, at least to my knowledge, there aren't too many plesiosaur (sensu lato) genera that have striations all around the circumference of their tooth crowns. That having been said, as expressed, my hunch is also that this would be plesiosaur - I'm just not willing to put any money down on it, because, without careful analysis of the tooth's ornamentation, the likelihood of it being crocodile is much greater.

 

1 hour ago, will stevenson said:

I will see if I can get some better close ups of the striations when I get home on Monday

 

Cool! I'll keep my eye out for them

 

1 hour ago, will stevenson said:

someone thought metriorhynchus was a possibility

 

Though one of the two possibilities for the identification of this tooth I see is for it to be thalattosuchian (i.e., marine crocodile), this would definitely have to be teleosauroid rather than metriorhynchoid. The latter show a certain degree of lateral compression not evidenced by this tooth and bear minimal striations that, moreover, wear off rapidly and therefore are often not easily observed on fossil specimens.

 

 

These Dakosaurus sp. teeth from the Boulonnais in France (source) are good examples of metriorhynchid teeth, as are the various specimens below:

 

 

 

 

They are the more commonly found (or, at least, recognized) type of marine crocodile from the Oxford Clay, though teleosaurus were certainly present as well (I've got various teeth in my collection that were sold to me as plesiosaur teeth, but ended up being teleosaur; I still need to update my thread here at some point). @PointyKnight has written a good identification guide on these metriorhynchid teeth, might you be interested.

[PointyKnight]

@pachy-pleuro-whatnot-odon is correct, Tricleidus.

[Notidanodon]

On 2/18/2022 at 10:40 AM, Ossicle said:

Fantastic tooth!

 

It looks more similar to my plesiosaur tooth than my crocodile teeth from the Oxford Clay, but that's a very superficial similarity and nothing I have is quite this shape. It's a very distinctive, interesting tooth.

 

Clearly from what has been posted crocodile teeth are more varied than I understood, so it could be, but it looks more plesiosaur to me.

 

 

 

 

Thanks for your help! It’s great to know it’s plesiosaur, I thought it looked different to my croc teeth as well  

[Notidanodon]

On 2/18/2022 at 11:08 AM, pachy-pleuro-whatnot-odon said:

 

Unfortunately, you often see a lot of crocodile teeth misidentified as plesiosaur. Thing is, though, that, at least to my knowledge, there aren't too many plesiosaur (sensu lato) genera that have striations all around the circumference of their tooth crowns. That having been said, as expressed, my hunch is also that this would be plesiosaur - I'm just not willing to put any money down on it, because, without careful analysis of the tooth's ornamentation, the likelihood of it being crocodile is much greater.

 

 

Cool! I'll keep my eye out for them

 

 

Though one of the two possibilities for the identification of this tooth I see is for it to be thalattosuchian (i.e., marine crocodile), this would definitely have to be teleosauroid rather than metriorhynchoid. The latter show a certain degree of lateral compression not evidenced by this tooth and bear minimal striations that, moreover, wear off rapidly and therefore are often not easily observed on fossil specimens.

 

 

These Dakosaurus sp. teeth from the Boulonnais in France (source) are good examples of metriorhynchid teeth, as are the various specimens below:

 

 

 

 

They are the more commonly found (or, at least, recognized) type of marine crocodile from the Oxford Clay, though teleosaurus were certainly present as well (I've got various teeth in my collection that were sold to me as plesiosaur teeth, but ended up being teleosaur; I still need to update my thread here at some point). @PointyKnight has written a good identification guide on these metriorhynchid teeth, might you be interested.

Thankyou so much   if you want I may be able to send it over to you so you could have a closer look, I didn’t think the striations looked like they belonged on a croc tooth (at least compared to mine  )  I will check out that guide!

[pachy-pleuro-whatnot-odon]

2 hours ago, will stevenson said:

Thankyou so much   if you want I may be able to send it over to you so you could have a closer look, I didn’t think the striations looked like they belonged on a croc tooth (at least compared to mine  )  I will check out that guide!

 

Between the import taxes that shipping the tooth would incur at both ends, my own hunch and everybody else here seeming to think it's a plesiosaur tooth, I don't think it'll be necessary to ship the tooth across, though I appreciate the proposal (a good alternative, by the way, would be a video of high enough quality/resolution to show all sides of the tooth and the striations on it)

 

I guess it's just that I've become more weary of outright identifying fully striated teeth as either plesiosaur or croc following my misidentification here. For while in the presence of carinae identification is often an open and shut case, I've learned from the many teleosaurid teeth I've seen that the carinae may not always be so obvious and can wear down. In those cases where the carinae don't stand out for their boldness, you can often still identify them for the fact that the other striations on the tooth run into the carinae and terminate there, as opposed to in plesiosaurs where they tend to bundle the closer you get to the tooth apex, with some dropping away to make space for others. I've also learned not to base myself purely on the nature of the striations on such teeth for purposes of identification, as not only may striae wear down in both crocodiles and plesiosaurs, but there's also a high degree of intra- and intergeneric as well as individual variation. In both crocodiles and plesiosaurs striae may terminate prior to reaching the tooth apex (sometimes long before doing so) and may, that way, form gradated ornamentation, as in the specimen under discussion here. The point being that I don't think you can rely on the nature of the striations to differentiate between plesiosaur and teleosaur - moreover so since Tricleidus seeleyi can have a single apicobasal ridge that looks deceptively like a carina. It's for this reason older publications, like the one mentioned by @Manticocerasman here, will often state that it's impossible to differentiate between steneosaur and plesiosaur teeth.

 

What I found to be the differentiating factor between the two, based on the pair of Tricleidus sp. teeth I've seen come out of the French Boulonnais is that the striations on the plesiosaur teeth split into two bundles in the upper half on one side of the tooth, in a place that's located along the imaginary line of where a carina might be (i.e., imagine a carina on one side of the tooth where in reality striations run towards the apex; about halfway up, the striations will split and new ones will sprout from in between). See the image below to see what I mean. In addition, it appears that Tricleidus-teeth are slightly compressed, given them a somewhat oval cross-section, although I can't verify this beyond my own specimen.

 

 

As I'm not seeing these features on the tooth discussed here, I'm still hesitant to simply call this a Tricleidus-tooth (would love to see more examples if anybody has them), though I can't really make out clear carinae either - using either of the methods outlined above. So, I guess that's what made me intuitively consider this a plesiosaur tooth rather than a crocodilian one... I'd just keep it at that

[RuMert]

19 minutes ago, pachy-pleuro-whatnot-odon said:

the striations on the plesiosaur teeth split into two bundles in the upper half on one side of the tooth, in a place that's located along the imaginary line of where a carina might be

Need to see it on a whole tooth, this one can be altered by fractures

[pachy-pleuro-whatnot-odon]

11 minutes ago, RuMert said:

Need to see it on a whole tooth, this one can be altered by fractures

 

This feature is present on two teeth from the same region that I've seen, the other belonging to @Manticocerasman. And while that other one indeed is broken too - as are many plesiosaur teeth from the Boulonnais - I'm confident that the feature we're seeing is not an artefact: not only have both teeth been correctly restored, as evidenced by both the overall shape and striations matching up, but I've yet to come across as tooth that changed it ornamentation by being broken, whether during collection or preparation from the host rock (these teeth have not been put together from separate parts). I can therefore not conclude but that this feature is real. That having been said, I've since been looking for other confirmed examples of Tricleidus-teeth to add to my collection, so that I can either further substantiate or disprove my findings... Differentiating between fully striated plesiosaur and teleosaur teeth can get very tricky at times... 

[pachy-pleuro-whatnot-odon]

Just to add to the discussion of the forked striations on Tricleidus-teeth: as I received another Callovian plesiosaur tooth from the UK today, I happened to take another look at my Muraenosaurus leedsi tooth for comparison when I noticed it too has a bifurcation about two-thirds up the way to the tooth apex, and only on one of the tooth's edges. Below is a photograph illustrating this characteristic. In this case, though, rather than the striae continuing all around the circumference of the tooth, the labial surface is devoid of ornamentation, clearly marking my two teeth as belonging to different species of plesiosaur, yet both cryptoclidids. As such, I wonder whether this bifurcation could be a shared trait that can be used to easily identify teeth as plesiosaurian.