Liopleurodon/pliosaur Tooth?

[pachy-pleuro-whatnot-odon]

6 hours ago, paulgdls said:

Well. I'm gobsmacked about that first tooth. Is that in your collection? The enamel appears to be about 5.5 to 6 inches long, which would make the total length with root 18 inches plus. Skull length 3m plus if Liopleurodon.  This is larger than the largest tooth in the Leeds collection at the NHM (length on the mid line 14.75 inches). Also the coarseness and spacing of the ridges is amazing. Certainly very coarse for Liopleurodon as described by Lesley Noe et al. Pachycostasaurus dawni has similarly coarse ridges and spacing but I believe only one specimen has ever been found and that is much smaller.

 

I don't know... Although I have to agree that the striae are a lot coarser/bolder than those typically seen on Liopleurodon, I don't think the size itself is out of range. Take a look at the below Liopleurodon ferox tooth from the Oxford Clay at Whittlesey in the Peterborough area, now held by the Wollaton Hall. A rough estimate comparison with my smart phone puts it at about 14 cm as well, without root (sources: Jed Taylor & Sven Sachs).

 

 

The general shape and striations of the new photograph also really make me think of Liopleurodon.

 

1 hour ago, RuMert said:

 

[pachy-pleuro-whatnot-odon]

I, unfortunately, still need to catch up on the thread about Oxford Clay plesiosaur teeth, thus others may be more knowledgable in this than I am. But here's my opinion anyway:

 

8 hours ago, RuMert said:

 

I'd consider this a Liopleurodon cf. ferox tooth, based on the bold/coarse striations, the conical shape of the tooth and the one smooth side.

 

8 hours ago, RuMert said:

 

I did a bit of digging to find the provenance for this one, as I felt that the density of striations is a bit high for the proposed Simolestes. And, while the tooth was found in Ryazan Oblast, it was found on a shore that carries both Callovian and Cretaceous material.

 

Quote

Unfortunately, the exact age (Jurassic or Cretaceous) cannot be named, since it was found on the shore, washed out of the rock.
There is an assumption that this is the late Callovian.

 

As such, I think my initial impression of this being a brachauchenine tooth - or, what used to be called Polyptychodon in the past - might still be tenable.

 

8 hours ago, RuMert said:

 

If this wouldn't have been said to come out of Callovian deposits, I'd say these most resemble Pliosaurus cf. carpenteri (see also this thread). As it is, I think they may well be Simolestes for the number of ridges that reach the full apicobasal length of the crowns.

 

Teeth of P. carpenteri, for comparison. Modified after figure 4 from Sassoon, Foffa and Marek (2015).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8 hours ago, RuMert said:

 

With this tooth being so fragmentary, I don't think it's possible to determine a species for it. That is, many of the diagnostic features are not available, especially as I believe the coarseness of the stria still falls within what may be seen in Liopleurodon.

 

8 hours ago, RuMert said:

 

This tooth is also rather too damaged to properly based on ID on. However, the general shape and density of striations seems to correlate well with the examples Paul gave for Simolestes. So, I'd say that's definitely an option.

[DE&i]

@RuMert sorry couldn't help, I've a few in my collection but not these one's.

 

Hi @paulgdls hope you're well. 

[RuMert]

On 3/6/2021 at 3:52 AM, pachy-pleuro-whatnot-odon said:

here's my opinion anyway:

Thanks a lot! You're quite a detective

I doubt the 2nd tooth comes from the Cretaceous, in that site there are lots of Callovian and maybe a couple of weak Cretaceous lenses which could be depleted by now. Also doesn't it look much like the 3rd? (at least to my eye). Agreed on the rest

 

On 3/6/2021 at 9:22 AM, DE&i said:

sorry couldn't help, I've a few in my collection but not these one's.

You did help a lot with those photos, I'll use them for future reference. I'm just not experienced yet to fully grasp pliosaur ID methods. I should come to the UK and see those museums and specimens in person, but it'll take time with the pandemic and RF-UK relations

[pachy-pleuro-whatnot-odon]

On 3/6/2021 at 11:54 AM, RuMert said:

I doubt the 2nd tooth comes from the Cretaceous, in that site there are lots of Callovian and maybe a couple of weak Cretaceous lenses which could be depleted by now. Also doesn't it look much like the 3rd? (at least to my newbie eye). Agreed on the rest.

 

Well, Cretaceous lenses being less prominent at the site doesn't exclude the tooth still coming from one of these lenses. However, I agree it lessens the chances. All the same, morphologically it is, in my opinion, a much closer match to Polyptychodon sp., in terms of density and distribution of striae, than Simolestes. It's clearly not a Pliosaurus sp., as in the third image, though, as its cross-section is not (sub)trihedral, nor is one of the sides smooth.

[pachy-pleuro-whatnot-odon]

On 3/6/2021 at 11:54 AM, RuMert said:

You did help a lot with those photos, I'll use them for future reference. I'm just not experienced yet to fully grasp pliosaur ID methods. I should come to the UK and see those museums and specimens in person, but it'll take time with the pandemic and RF-UK relations

 

Don't worry too much about not being able to properly identify pliosaur teeth yet. I can't really either yet

 

I mean, as I doubt I need to tell you, identifying any marine reptile teeth to genus, let alone species, is incredibly hard (not in the least because marine reptile teeth are typically not their most diagnostic body parts). One only needs to take a look at the discussions on mosasaur teeth identification (especially Moroccan, as they are so ubiquitous) in various places to get an impression on how heated these debates can get and how little can be ascribed with sufficient certainty. I mean, sure, there are always genera or species with teeth so unique as to make ascription easy. But, more often then not, these identifications are best effort at best (see here, here and here for a recent attempt of mine to identify some Temnodontosaurus spp. ichthyosaur teeth) - even if you have been able to visit the appropriate museums (as is nicely illustrated in the aforementioned sample concerning ichthyosaur teeth).

 

It's also not always necessary to visit museums in person. Some have parts of their collection online (most notably, these may be parts of the collection not on public display), which can then be searched for the same or even better information than is available to a regular visitor to the museum. Here are a couple of example sites:

• Natural History Museum Data Portal collection specimens
• Jurassic Coast Fossil Finder Database

When it comes to pliosaurs, the situation is not much different - if not worse, as pliosaurs have generally got very similar tooth morphologies. This is further aggravated by aspects such as heterodonty; subjectively scored characteristics, like the coarseness of ridges; and distinguishing features - such as vermiculated enamel or as the bifurcation and reticulation of striae - being inconsistently present or absent. To add insult to injury, I've come to understand that the number of striae on pliosaur teeth reduce with ageing of the animal, so that some teeth may be entirely smooth, further decreasing their diagnostic features (see below images for examples; don't remember where I picked this titbit of information us, though):

 

Pliosaurus (Liopleurodon) ferox at the Natural History Museum, accession number PV R 4747

 

 

 

 

 

 

 

 

 

Liopleurodon ferox at the Natural History Museum, accession number PV R 2449

 

 

 

 

 

 

 

 

 

Teeth of the Liopleurodon ferox specimen at the Paläontologische Sammlung at the MUT Tübingen. Note the one tooth with remaining striations in the mandible. As discussed with Paul, the teeth are inserted.

 

 

 

 

 

 

 

 

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.

[RuMert]

A useful analysis, thank you I hope to find a bit more teeth in April to start distinguishing between them. Unfortunately the weather is not promising so far (need the ice to melt before that)

[pachy-pleuro-whatnot-odon]

1 hour ago, RuMert said:

A useful analysis, thank you I hope to find a bit more teeth in April to start distinguishing between them. Unfortunately the weather is not promising so far (need the ice to melt before that)

 

Wow! I'd also like to say I'm planning to go out hoping to find more. But finding even a single pliosaur tooth this side of Europe is a rare occurrence! I'm very jealous!

[RuMert]

Wishful thinking We'll see 

[RuMert]

https://www.researchgate.net/publication/326408819_Evolution_and_disparity_of_pliosaurid_teeth_and_the_influence_of_the_Jurassic-Cretaceous_transition

"Unexpectedly, these teeth belong to widely distinct morphotypes, including the first report of conical-toothed pliosaurids from the latest Jurassic–earliest Cretaceous interval. This challenges the hypothesis that only one lineage of pliosaurids crossed the Jurassic–Cretaceous boundary. It appears that conical-toothed pliosaurids coexisted with their trihedral-toothed relatives for at least 25 million years over the Jurassic-Cretaceous transition. In fact, our quantitative analyses indicate that pliosaurids reached their maximal dental disparity (in both size and shape) during this interval, showing little evidence of a turnover associated with the Jurassic–Cretaceous boundary. Instead, disparity decreased later in the Early Cretaceous, with the disappearance of trihedral-toothed forms in the Barremian'.

[paulgdls]

Here is Zverkov's poster: