Pliosaur tooth?

[Pliosaur]

Hello!

 

Curious if this could be a teeth from pliosaur Simolestes Vorax 

Teeth does exhibit signs on crushing and measures approximately 30mm, has signs of striations common with pliosaur teeth

 

Additional Details 

Jurassic, Oxford Clay

Peterborough Cambridgeshire UK

 

Attached pictures 

 

[Pliosaur]

Liopleurodon Ferox tooth for comparison 

[Pliosaur]

Simolestes Vorax tooth for comparison 

From Oxford Clay of Peterborough 

[Manticocerasman]

@pachy-pleuro-whatnot-odon

[pachy-pleuro-whatnot-odon]

Hi Gabriel,

Isn't this the same tooth you posted about eight years ago, in 2014?

 

 

As discussed in that thread, this is without a doubt a pliosaur tooth. However, the genus may be difficult to determine. If it can be established that the tooth was found in the Kosmoceras jason Zone of the Oxford Clay (which seems likely, based on the below citations by @paulgdls, taken from the thread referenced above) the colour and coarseness of striations may be indicative that of the tooth indeed being attributable to S. vorax.

 

On 2/3/2021 at 9:10 PM, paulgdls said:

The colour and ridge coarseness may indicate this species rather than Liopleurodon ferox, the teeth of which tend to have grey enamel see (excerpt from Lesley Noe Phd describing Simolestes vorax teeth characteristics):

 

"The teeth very frequently preserve a `vitreous' texture or lustre and a rich dark brown colour not seen in the
other genera. "

 

On 2/4/2021 at 6:39 PM, paulgdls said:

The bituminous layer extends over a wide area - right down to Oxford and SW of there. Nearly all the articulated vertebrate skeletons from the OC came from this layer. Alfred Leeds didn't identify the precise layer from which his specimens came unfortunately but, as Dave Martill points out in his book and as I have found myself, virtually all the vertebrate material is in the bottom few metres of the OC. Why this is, is not known.

 

More traditionally, however, one would study the exact nature of the enamel and its ornamentation, as below (originally described in this post):

 

On 3/11/2021 at 5:38 PM, pachy-pleuro-whatnot-odon said:

Based on our current understanding of pliosaur teeth, however, the following characteristics can be used to identify them:

• Geological age of the tooth: whether it's Cretaceous, Upper Jurassic or pre-dates the Kimmeridgian
• Whether the tooth is rounded/conical or (sub)trihedral
• Whether the tooth enamel is vermiculated (what would be called anastamosing in mosasaurs)
• Whether stria are located on the tooth's labial (does not occur in pliosaurs, as far as I'm aware, though it has been described for plesiosaurs [sensu lato]) or lingual surface or all around the tooth
• Coarseness and apicobasal height distribution of striae
• Whether striations bifurcate and/or reticulate
• Apical fusion of striae
• In some cases, even colour (see here and here)

From these general rules, the following can be derived:

1. Cretaceous teeth are round/conical, can have any number of striations, and are brachauchenine.
2. (Sub)trihedral teeth are restricted to the Late Jurassic and belong to the genus Pliosaurus, with (as far as I'm aware) only P. kevani and Pliosaurus (Stretosaurus) macromerus having subtrihedral teeth.
3. Teeth prior to the Kimmeridgian are round/conical:
   • Teeth from the Triassic and Early Jurassic with only labial striations are rhomaleosaurid.
   • For the Middle Jurassic a division can be made into a) the "robust" teeth of pliosaurs with a short mandibular symphyses (sensu Tarlo [1960], p. 150) and b) more "gracile" teeth belonging to pliosaurs with long mandibular symphyses (ibid.)
     1. Of the species with robust teeth, those of Liopleurodon sp. have both vermiculated enamel as well as reticulating striations, while Simolestes sp. lacks both these features.
     2. Of the species with gracile teeth, those of Peloneustes sp. have striae all around, whereas those of 'Pliosaurus' andrewsi has them only lingually, yet is almost indistinguishable from Peloneustes in all other aspects.
     3. Teeth with apically fused striae belong to derived thalattophoneans (which for the Middle Jurassic corresponds to Tarlo's (ibid.) species with short symphyses), Liopleurodon sp. and Simolestes sp. in particular.

 

Undoubtedly this is cutting corners here and there, but I hope it will nonetheless form a good starting point for pliosaur tooth identification.

 

The table below (Table 1 from Sassoon, Foffa and Marek, 2015) also follows a similar strategy to distinguish between the teeth of different pliosaurs:

 

 

Moreover, @paulgdls, citing Noé, makes the following remarks here:

 

On 2/10/2021 at 11:48 AM, paulgdls said:

On Simolestes again: "The bottom of the enamel ridges very infrequently displays reticulations, and the
enamel is rarely vermiculated."

 

On Liopleurodon: "Occasionally the enamel ridges bifurcate or
reticulate close to the bottom of the enamel, and rarely additional enamel ridges are added
between the existing ornamentation, some distance above the bottom of the enamel (figure 24)."

 

He, furthermore, observes that:

 

On 2/10/2021 at 11:48 AM, paulgdls said:

Noe calls the fusion reticulation. He says its rare in Simolestes but occurs quite commonly near the base of the enamel in Liopleurodon.

 

 

 

All weighed together - colour, fine enamel compared to L. ferox, and lack of both visible bifurcations and reticulations - this could certainly be a Simolestes vorax tooth. However, as the base of the tooth does not exhibit the "crescent shaped region of unridged enamel" described by Sassoon, Foffa and Marek (ibid.) and illustrated in Tarlo's (1960) figure of Upper Jurassic pliosaur teeth below under B, as well as visible in the second (lower) S. vorax comparison tooth above, another possibility, in my opinion, might be that the tooth is attributable to Liopleurodon pachydeirus. These teeth would be very similar to those of L. ferox, only with less coarse striations.

 

 

 

 

Hope this helps.

Edited September 9, 2022 by pachy-pleuro-whatnot-odon

[Pliosaur]

Hello!

 

@pachy-pleuro-whatnot-odon Thanks for your response! I posted that initial discussion about 8 years ago when I was quite young, and now I've gone into studying marine vertebrate paleontology so I thought I'd like to revisit this fossil so get a clear and accurate identification! From what you've said I do think it belongs to a species of Liopleurodon 

 

Below I've made a comparison of "brown color" identified Liopleurodon tooth from Oxford Clay Peterborough England vs the tooth in question 

Looks pretty similar 

 

 

[pachy-pleuro-whatnot-odon]

15 hours ago, dinosaur12lee said:

I've gone into studying marine vertebrate paleontology

 

Oh wow! I'm so jealous! While I studied archaeology and had a great time, my bigger passion probably remains marine reptile palaeontology and I wish I'd had studied it at the time. Where are you following your classes? Do you know if they happen to have some kind of distance program? I've been thinking for some time I might want to do something like that...

 

As to the teeth: again, colour is never a good indicator seeing as colour results from the particulars of the permineralisation process, which will differ from place to place and from layer to layer. However, seeing as there are Liopleurodon-teeth with this colour (presuming their identification was correct) makes it much more likely that in absence of more diagnostic features, such as the nature of the striations, your tooth could indeed belong to Liopleurodon sp. One supporting argument is that, although I could be mistaken, the last image of your tooth shows a bit of ridgeless enamel on the label surface (to the right on the photograph), which I believe is a feature of Liopleurodon, rather than Simolestes (though I'm not entirely sure about that). In any case: nice one!

 

Cheers,

Alexander.

Edited September 10, 2022 by pachy-pleuro-whatnot-odon

[Pliosaur]

@pachy-pleuro-whatnot-odon It's surprising that I made the initial post about the pliosaur tooth so long ago, I was 13 then and now I'm almost 22 now! Time does go by quick! Just wanted to check on this forum and start posting again. I'm planning on getting a masters studying marine vertebrate paleontology at Pennsylvania State University! It's always interesting to see the different variations of pliosaur teeth and trying to identify them based on geography and distinguishing features!

 

I think you bring up some good points that color is not always a good indicator of the tooth, also because this tooth is relatively crushed and not complete it makes identifying the species even more difficult, however Liopleurodon and Simolestes seem to be the strongest candidate for the tooth as you mentioned!