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Juvenile Pliosaurus tooth?


DatFossilBoy

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DatFossilBoy

Hey guys,

I have this marine reptile tooth from the Ryazan region ,Russia.

I was wondering what it could be, it’s really tiny at 6mm.

It ressembles the morphology of plio teeth but I’ve never seen plio teeth that small.

Hoping someone could help.

Regards

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pachy-pleuro-whatnot-odon

Tricky one. The striations look rather rounded, which could make an argument for ichthyosaur. However, I'm more inclined to believe this is due to preservation, if not exacerbated by the tooth's small size (well done ontaking such clear photographs!), as most teeth I've seen from that locality have similarly rounded striations, even if clearly plesiosaurian. Robustness and morphology are consistent with pliosaur ratchet teeth (distal in the jaw). Close to the right most teeth in the image below (figure 4 from Sassoon, Foffa and Marek, 2015). In fact, @RuMert has stated that "in [...] Ryazan [...] 90% of such Cretaceous teeth will belong to pliosaurs".

 

Pliosaurid-teeth-from-different-regions-of-the-jaw-scaled-to-same-height-to-highlight.thumb.png.289d7eb77d8dff3f63b566970516e8a2.png

 

@Anomotodon, however, attributes most of these teeth to Leptocleididae, although I'm unsure on what exact grounds, as some of the ones classed as leptocleidid to me appear pliosaurian.

 

It is possible that part of the confusion derives from the fact people have a tenancy to call polycotylid remains - and by extension, probably, leptocleidid too - pliosaur (which, according to current analysis, is not true). But I'd call this one a pliosaur...

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

part of the confusion derives from the fact people have a tenancy to call polycotylid remains - and by extension, probably, leptocleidid too - pliosaur

Exactly. Plus Polyptychodon (as I heard in this case it was used as a wastebasket taxon). Ichthyosaurs are excluded (extinct by the time of Ryazan Oblast (Shatsk) sediments), so the reptile teeth alternatives are elasmosaurs and "pliosaurs" with most teeth attributed to the latter.

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Anomotodon

I think it is an ichthyosaur tooth. Pliosaur teeth have a distinct striation pattern, with very well-pronounced striations forming different patterns between tip and base. Some Jurassic genera like Liopleurodon, also have striations only on one side of the crown, although I am not sure how common it is among Cretaceous pliosaurs. Ichthyosaurs, on the other hand, have fewer and shorter ridges, just like the tooth in question.

 

Also ichthyosaurs were still present in the Cenomanian of Russia, they went extinct at the Cenomanian-Turonian boundary.

 

2017-05-21-2670-1000.jpgFossil Locator on Twitter: "A massive "Icthyosaur" tooth from the Lyme  Regis region of the UK. I think it's actually a pliosaur tooth. Label from  the Victorian era. #fossilfriday… https://t.co/yf76L5ztcr"Broken teeth of the pliosaur Brachauchenius lucasi (both curated as... |  Download Scientific Diagram

 

Here is a Cretaceous pliosaur tooth also from a posterior position

 

Very rare Pliosaur tooth Polytychodon Interruptus

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pachy-pleuro-whatnot-odon
2 hours ago, Anomotodon said:

I think it is an ichthyosaur tooth. Pliosaur teeth have a distinct striation pattern, with very well-pronounced striations forming different patterns between tip and base. [...] Ichthyosaurs, on the other hand, have fewer and shorter ridges, just like the tooth in question.

 

Also ichthyosaurs were still present in the Cenomanian of Russia, they went extinct at the Cenomanian-Turonian boundary.

As stated in my original post, I agree that the decoration on the tooth looks rather rounded, as one would expect for ichthyosaur teeth. Not knowing the quarry or geological origin of the Ryazan reptile teeth, however, I misinterpreted what I read about them to mean that the dating of these teeth was such that they post-dated the Cenomanian-Turonian boundary. I've just looked up some information about the Shatsk quarry and, indeed, the deposits there are dated to the Cenomanian stage of the Late Cretaceous. Thus, ichthyosaur would still belong to the possibilities, and I'd need to re-evaluate my opinion.

 

For, though it is true that the enamel folds of ichthyosaurian teeth are more uniform in size and height than are the sharper outlined and more irregular pliosaurian tooth striations, the ornamentation of the tooth in question is not extremely clear on this matter:

 

1E2C01D0-8517-4FED-B93E-4926EE84D41F.jpegLooks more like ichthyosaurian enamel folds...

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6418E6B0-1067-4037-85C6-9785F3195471.jpegAnastomosing ridges look more plesiosaurian (and by extension pliosaurian) in nature and are much thinner than in the image above. Also observe that some of the ridges appear to continue after others have ended, which is also a pliosaurian feature.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Overall, though, I still believe there are more indications for this tooth being pliosaurian - as per @RuMert's claim that most are assigned this label - than ichthysaurian. For, one of the things to keep in mind about ichthyosaurs during this time is that they would, to the best of current scientific knowledge, all be platypterygiine ichthyosaurs - which tooth crowns have enamel ridges that end all at the same height prior to the tooth apex (generally a trait of the teeth of ophthalmosauridae). This is clearly not the case here. Also, the curvature of the tooth to me seems to more suggest pliosaur than ichthyosaur: of those platypterygiine teeth I've seen, the inner arch of the tooth is consistently almost vertical, with the rounded impression being obtained from the outer curve. Pliosaurian teeth, on the other hand, curve both front and back...

 

Lastly, keep the diminutive size of this tooth in mind, as I've found that the ornamentation of teeth doesn't scale equal to the tooth's overall size. Thus, one might expect relatively thicker striae on smaller teeth.

 

Thus, I stick with my original conclusion: pliosaur ratchet tooth.

 

2 hours ago, Anomotodon said:

Some Jurassic genera like Liopleurodon, also have striations only on one side of the crown, although I am not sure how common it is among Cretaceous pliosaurs.

Thought to be a waste-bucket taxon, teeth with smooth sides or with only a few striae are quite commonly known for Polyptychodon. See Madzia (2016), "A reappraisal of Polyptychodon (Plesiosauria) from the Cretaceous of England", of which figure 4 is reproduced below:

 

peerj-04-1998-g004.jpg.8f31272812f92198c02a546727267fe2.jpg

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

I misinterpreted what I read about them to mean that the dating of these teeth was such that they post-dated the Cenomanian-Turonian boundary

In theory we can refer to the Cenomanian-Turonian extinction event but in practice out of 250 Russian Cenomanian marine reptile remains on ammonit.ru nothing was positively attributed to ichthyosaurs except for Stary Oskol,  which is Albian-Cenomanian, and a couple of obscure locations. Here's the complete list with Stary Oskol excluded, you can check for yourself and maybe find lots of incorrectly ID'ed ichthyosaur teeth. As for me, I'm not so interested in the Cretaceous

 

P.S. I found the search results are somehow not saved in the links, so to see them you need to check squares on the left (Cenomanian), middle (Russia) and right (marine reptiles)

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pachy-pleuro-whatnot-odon
1 hour ago, RuMert said:

In theory we can to refer the Cenomanian-Turonian extinction event but in practice out of 250 Russian Cenomanian marine reptile remains on ammonit.ru nothing was positively attributed to ichthyosaurs except for Stary Oskol,  which is Albian-Cenomanian, and a couple of obscure locations.

I didn't quite go through all of it (might make a nice basis for an academic analysis ;)), but did indeed notice a paucity of reported ichthyosaur remains - though some locations have an above-average amount of teeth that I find difficult to positively ID as either ichthyosaur or pliosaur from photographs alone, such as the Varavinsky Ravine. All the same, judging by size and shape these too are likely pliosaurian teeth. Mostly, however, I looked at the material found at the Shatsk Quarry. Amongst these, I found two teeth that I'd call plesiosaurian/pliosaurian (even if not clearly so) with similar features as OP's in that their striations stop equidistant from the tooth-apex (1, 2). One of the teeth has indeed been identified as pliosaur, while the other is simply recorded as a marine reptile tooth:

 

158400316786107-big.thumb.jpg.2d267bd46c0d95b39b9e981196070742.jpg137304698204326-big.thumb.jpg.790c93f40f4be08aedc572162a9152d1.jpg

 

 

Interestingly, I also came across the below two specimens. The tooth seems to exhibit enamel-folds that terminate equidistant from the tooth-apex, consistent to a Platypterygius tooth; whereas the vertebra, though described as plesiosaurian, appears to concave to be plesiosaurian and could thus be ichthyosaurian. What do you guys make of these?

 

153302997598525-big.thumb.jpg.8016fd4bdb8b6ad2d5fbbaea4e4e1b35.jpg147766862077341-big.thumb.jpg.dd9cc31b6b895026d00303cf5448a5f2.jpg

 

In general, though, teeth from this quarry seem to be assigned to either Leptocleididae, Pliosauridae or, in a single rare case, Elasmosauria.

 

154805244218831-big.thumb.jpg.5de4d6228376c559540231fed4587f2a.jpg146953561188359-big.jpg.312f02439f210f3a06658affb4803efe.jpgFragment is elasmosaurian from Shatsk Quarry and shows labiolingual flattening typical of elasmosaurian teeth, but with unusual ornamentation. Normally, you'd expect the tooth ornamentation to be more like that of the more complete tooth from Varavinsky Ravine.

 

 

 

 

 

 

 

 

 

140773758760946-big.thumb.jpg.5d774d939c9bae5f4dbf983bf41169fa.jpgPliosaurian tooth attributed to nomen dubium taxa Polyptychodon.

 

 

 

 

 

 

 

 

 

 

 

 

Below: various teeth referred to Leptocleididae (1, 2, 3, 4), although I'm unclear on what grounds they have been attributed. That is, there doesn't seem to be too much consistency in the boldness or distribution of the striae, nor in whether they anastomose or not. Tooth shape doesn't appear determinative either. Based on my personal experience with pliosaurian and polycotylid teeth, I'd be inclined to only ascribe the anastomosing striae of the reddish tooth (which should be familiar to you, @Anomotodon ;)) as cf. Polycotylidae, i.e. Lepctocleididae. The rest I'd simply call pliosaur, since, as far as I know, only they have as many and as pronounced striations. True, they are not as densely striated as the know Cretaceous species of Polyptychodon (sensu lato) and Brachauchenius, but their morphologies compare favourably to Jurassic pliosaur tooth specimens.

 

159941719579271-big.thumb.jpg.24e050ccda56208dd7d6bdd8a9c37195.jpg159942058919086-big.thumb.jpg.78ea44224a91bf2217400d72570a1969.jpg156222683497404-big.thumb.jpg.b24fde9748b97d1a4531fe7c11fe3c91.jpg

 

153720679057021-big.thumb.jpg.7e0d8f8a35f2d31c46cacc0aaeab14c0.jpg

 

 

I therefore don't see reason to change my original opinion on the tooth being pliosaurian.

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Anomotodon

There is indeed lots of material from the Cenomanian of Russia online, although none if it had been published, as far as I am aware. I have to admit, I am not entirely positive about this tooth being ichthyosaurian because it is worn, so I wouldn't entirely exclude non-elasmosaurian plesiosaurs - Leptocleidia, either.

 

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

Anastomosing ridges look more plesiosaurian (and by extension pliosaurian) in nature and are much thinner than in the image above. Also observe that some of the ridges appear to continue after others have ended, which is also a pliosaurian feature.

 

Anostomosing ridges are not exclusive to plesiosaurians, but also present occasionally in ichthyosaur teeth (see C on the fig below, McCurry et al., 2019 - very interesting paper by the way). Lingual curvature is also present in some tooth positions. Pliosaurian teeth generally have much more frequent striations triangular in cross section (see fig below). Poor preservation does not help, but ornamentation does not match either way. I am leaning more towards ichthyosaur rather than leptocleidid because of distal curvature of their posterior teeth and short and triangular shape of the tooth in question, but wouldn't be surprised if it turns out to be a plesiosaur instead. In this fauna, large pliosaurs and elasmosaurids (most distinct feature is strong labio-lingual compression, absent in Leptocleidids) are the only taxa that can be identified with certainty imo

 

Phylogenetic distribution and morphological similarity of apicobasal ridges. The phylogeny was adapted from Kelley & Pyenson (2015) and Müller et al. (2010). Each lineage represents both independent evolution of apicobasal dental ridges and independent transitions between feeding in the terrestrial environment and feeding in the aquatic environment. The groups represented contain species that possess apicobasal dental ridges but may also contain species without the trait. Example photographs or computed tomographic renders of apicobasal ridged teeth (top) and close-up of the tooth surfaces (bottom). A, Deinosuchus rugosus (USNM 5351). B, Spinosaurus (ROM 64659). C, Ichthyosaurus (NMV P 202402). D, Pliosauridae indet. (NMV P 30660). E, Globidens alabamensis (USNM540758). F, Hydrurga leptonyx (NMV C 31561). G, Mammalodontidae indet. (NMV P 221271). Apicobasal ridges are also present in aquatic-feeding snakes (Vaeth et al., 1985), Paralonectes merriami (Nicholls & Brinkman, 1993), Tanystrophus longobardicus (Nosotti, 2007) and pterosaurs (Kellner & Tomida, 2000), but photographs of these are not depicted. Silhouettes were sourced from phylopic (http://phylopic.org/; Müller et al., 2010; Kelley & Pyenson, 2015).

 

Also another Russian Cenomanian platypterygiine tooth with anostomosing ridges

 

Зуб ихтиозавра рода Platypterygius - Рептилии

 

A - "Polyptychodon" - triangular and frequent ridges, E - Ichthyosaurus, rounded and less common ridges

 

Cross-sections through the teeth of various aquatic mammals and reptiles, showing where the enamel–dentine junction undulates approximately parallel to the outer enamel surface (B–F) or the ridges are formed by localized thickening of enamel (A). A, Polyptycodon interruptus (USNM 16153). B, Globidens alabamensis (USNM 540758). C, Goniopholis crassidens (USNM 16115). D, Spinosaurus aegyptiacus (ROM 64659). E, Ichthyosaurus communis (ROM 01860). F, Zygorhiza kochii (USNM 11962).

 

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

Thought to be a waste-bucket taxon, teeth with smooth sides or with only a few striae are quite commonly known for Polyptychodon. See Madzia (2016), "A reappraisal of Polyptychodon (Plesiosauria) from the Cretaceous of England", of which figure 4 is reproduced below:

 

This is very interesting, thanks for the information. I was under the impression that smooth labial side is a feature of Jurassic pliosaurs, but seems that in brachauchenins it is positional.

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Certainly the ridges look very thick for a pliosaur I.M.O. Worth remembering that the replacement teeth of these genera started off very small but with the ornamentation present  from square one see (Simolestes vorax) tooth 1 cm long:

 

20171125_0081.thumb.jpg.df56ed3dcfbd82c05bbc57470d713803.jpg

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pachy-pleuro-whatnot-odon
1 hour ago, paulgdls said:

Certainly the ridges look very thick for a pliosaur I.M.O. Worth remembering that the replacement teeth of these genera started off very small but with the ornamentation present  from square one see (Simolestes vorax) tooth 1 cm long:

 

20171125_0081.thumb.jpg.df56ed3dcfbd82c05bbc57470d713803.jpg

Beautiful tooth, Paul!

 

Indeed, since the smaller teeth of larger pliosaur individuals would have possessed striae of much the same thickness as on larger teeth - I was thinking about the posterior-most teeth, as these are also the most recurved, but replacement teeth might be an even better example - I'm thinking this is simply a small tooth from a large individual. Don't forget that the size of OP's tooth is 6mm, so about half the size of the one you just posted. Striae the size of what would fit on a 5cm+ tooth would look massive on such a small specimen.

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pachy-pleuro-whatnot-odon
2 hours ago, Anomotodon said:

Anostomosing ridges are not exclusive to plesiosaurians, but also present occasionally in ichthyosaur teeth (see C on the fig below, McCurry et al., 2019 - very interesting paper by the way). Lingual curvature is also present in some tooth positions. Pliosaurian teeth generally have much more frequent striations triangular in cross section (see fig below). Poor preservation does not help, but ornamentation does not match either way. I am leaning more towards ichthyosaur rather than leptocleidid because of distal curvature of their posterior teeth and short and triangular shape of the tooth in question, but wouldn't be surprised if it turns out to be a plesiosaur instead. In this fauna, large pliosaurs and elasmosaurids (most distinct feature is strong labio-lingual compression, absent in Leptocleidids) are the only taxa that can be identified with certainty imo.

That's certainly an interesting article you're referencing there! I'm adding that to my reading list!

 

Yes, I'm aware that the striations on plesiosaurian teeth are triangular in cross-section and that, in contrast, the enamel-folds of ichthyosaurian teeth (deriving from their plicidentine condition) are rounded (nice image, by the way!). However, as you yourself have noted, OP's tooth is rather worn, so that very little can be made out from the tooth itself - at least to this respect. That's also the reason I posted the image of the ichthyosaurian teeth from the same quarry above, as this specimen has clearly recognizable enamel-folds, not just proving ichthyosaurs were present at the locality, but also that they would've had the same clearly recognizable features as other platypterygiine ichthyosaurs. Size of the worn ridges on OP's tooth may therefore be suggestive, but I don't think they can be held entirely conclusive.

 

2 hours ago, Anomotodon said:

Phylogenetic distribution and morphological similarity of apicobasal ridges. The phylogeny was adapted from Kelley & Pyenson (2015) and Müller et al. (2010). Each lineage represents both independent evolution of apicobasal dental ridges and independent transitions between feeding in the terrestrial environment and feeding in the aquatic environment. The groups represented contain species that possess apicobasal dental ridges but may also contain species without the trait. Example photographs or computed tomographic renders of apicobasal ridged teeth (top) and close-up of the tooth surfaces (bottom). A, Deinosuchus rugosus (USNM 5351). B, Spinosaurus (ROM 64659). C, Ichthyosaurus (NMV P 202402). D, Pliosauridae indet. (NMV P 30660). E, Globidens alabamensis (USNM540758). F, Hydrurga leptonyx (NMV C 31561). G, Mammalodontidae indet. (NMV P 221271). Apicobasal ridges are also present in aquatic-feeding snakes (Vaeth et al., 1985), Paralonectes merriami (Nicholls & Brinkman, 1993), Tanystrophus longobardicus (Nosotti, 2007) and pterosaurs (Kellner & Tomida, 2000), but photographs of these are not depicted. Silhouettes were sourced from phylopic (http://phylopic.org/; Müller et al., 2010; Kelley & Pyenson, 2015).

When looking at figure C in this diagram I don't quite recognize what I would consider anastomosing. Sure, I see some ridges come together, but as far as I can tell this is simply because the tapering shape of the tooth makes them run together - which is only natural at a certain point towards the toot-apex. This in contrast to the anastomosing ridges found in mosasaurs that show a high degree of braiding, as do certain plesiosaur teeth. If you look exactly at the below pattern of striations, they waver and run into one another - something I find hard to consolidate with the structured repetition and folded nature of ichthyosaur tooth ridges.

 

6418E6B0-1067-4037-85C6-9785F3195471.jpeg

 

2 hours ago, Anomotodon said:

Also another Russian Cenomanian platypterygiine tooth with anostomosing ridges

 

Зуб ихтиозавра рода Platypterygius - Рептилии

Though a very interesting specimen with quite an unusual shape, I still hold the overall shape of the labial side of the tooth to be straight: it's just the tooth-apex making a slight carination that provides a bit of curvature. But the base is crown, which forms the lions-share of the tooth, is solid and fully upright.

 

I think the best conclusion to give this would be to say that OP's tooth is too worn to make it easily assignable to either sauropterygia or ichthyopterygia, with arguments to be made for both - though frequency of attribution of marine reptile teeth for the quarry where it was found strongly suggests Leptocleididae. My personal position is that this is a small pliosaur tooth of a sizeable (i.e. mature) individual, possibly a posterior tooth or a replacement tooth. I'll, however, leave it up to OP to make up their minds as to which argument is more convincing. Unfortunately, I don't think there's a way to provide the tooth with a label other than "marine reptile" without having to pick between sauropterygia and ichthyopterygia.

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  • 2 months later...

I recently saw marine reptile look alike pliosaur. 

It is similar to platypterygius or Ichthyosaurs, but that's root of tooth is different from both.

I want to know your opinion 

 

 

20210408_143538.jpg.8ff24a37bca3a527aeb0034f1713747f.jpg20210408_143553.jpg.9a1fb92706e67eeecb9e4eb3e2b8a38a.jpg

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pachy-pleuro-whatnot-odon
2 hours ago, Kim sung hyun said:

I recently saw marine reptile look alike pliosaur. 

It is similar to platypterygius or Ichthyosaurs, but that's root of tooth is different from both.

I want to know your opinion 

 

These teeth are often misidentified as pliosaur (and for understandable reasons), but are actually ichthyosaurian, belonging to Platypterygius sp.. Have a look at the below thread, which asks exactly the same question as you're doing here:

 

 

Even without root, you can tell the one from the other by looking at the ornamentation of the tooth crown: ichthyosaurs will have rounded enamel folds known as plicidentine, whereas pliosaurs have square or triangular striae. And while enamel folds typically run the circumference of the tooth equidistant to one another reaching the same apicobasal height, pliosaurian striations are less uniformly spread across the tooth and don't all have the same length. The two characters that seem to get people confused with these specific teeth are the shape of the root and the smooth apex. However, both are hallmarks of more derived ichthyosaurs, with the clear tooth apex being identifying for ophthalmosauridae and only the roots of less derived ichthyosaurian species showing the same folds as found on their teeth. In addition, while the roots of derived ichthyosaurs are considered to be square - and this is indeed the case - they often have a transitional portion, or neck, that is cylindrical in shape. Compare the below images:

 

1094044305_Evolutionofichthyosaurtaxonomicrichness(teeth).thumb.png.fbb75739154e445838e0de0e45cca934.pngFigure 18 from Fischer, Bardet, Guiomar and Godefroit, 2014. High Diversity in Cretaceous Ichthyosaurs from Europe Prior to Their Extinction

 

 

 

 

 

 

 

 

 

 

 

Platypterygius_tooth_with_root_2.jpg.e15904cae2b9e7403cd07ef4205796cc.jpgPlatypterygius_(Myopterygius)_kiprijanoffi_rooted_tooth_02.jpg.c6540ec38681b98255c0dde53040bfed.jpgPlatypterygius_(Myopterygius)_kiprijanoffi_rooted_tooth_with_tip_01.thumb.jpg.5859507dc57e27cd09f573faeb022a95.jpgPlatypterygius_tooth_with_root_1.jpg.49ee4f5dcb9f7c03f74141273d6418fd.jpg

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4시간 전, 파치-플레우로-이튼-이든은 이렇게 말했습니다.

 

이 치아는 종종 플리오사우르(그리고 이해할 수 있는 이유)로 잘못 확인되지만, 실제로 어류사우리아어로, 에 속한다플라티테리기우스반장님.. 아래 실을 보세요. 여기서 하는 것과 정확히 같은 질문을 합니다.

 

 

뿌리 없이도, 여러분은 치아 왕관의 장식을 보고 다른 사람과 구별할 수 있습니다: 어치티오사우르는 플리센틴으로 알려진 둥근 에나멜 접힌 반면, 플리오사우루스는 네모나 삼각 줄무늬를 가지고 있습니다. 그리고 에나멜 접기는 일반적으로 치아의 둘레를 서로 같은 무음부 높이에 도달하는 반면, 플리오사우루아 줄무늬는 치아에 걸쳐 균일하게 퍼져 있고 모두 같은 길이를 갖지 않습니다. 이 특정한 치아와 사람들을 혼동하게 하는 것 같은 두 캐릭터는 뿌리의 모양과 매끄러운 정점입니다. 하지만, 둘 다 더 많이 유래된 어치사우루스의 특징인데, 투명한 치아 정점이 안구과(葉葉葉)를 식별하고 있으며, 덜 유래된 어류사우리아종의 뿌리만이 이빨에서 발견되는 것과 같은 주름을 보여준다. 또한, 파생된 어치사우루의 뿌리는 사각형으로 간주되는 반면 - 그리고 이것은 실제로 그렇다 - 그들은 종종 모양이 원통인 과도기 부분 또는 목을 가지고 있다. 아래 이미지 비교:

 

1094044305_Evolutionofichthyosaurtaxonomicrichness(teeth).thumb.png.fbb75739154e445838e0de0e45cca934.png그림 18에서피셔, 바데트, 길오마르 그리고 고데프로이트, 2014. 유럽 백악기 어류사루의 멸종 전 고다양성

 

 

 

 

 

 

 

 

 

 

 

Platypterygius_tooth_with_root_2.jpg.e15904cae2b9e7403cd07ef4205796cc.jpgPlatypterygius_(Myopterygius)_kiprijanoffi_rooted_tooth_02.jpg.c6540ec38681b98255c0dde53040bfed.jpgPlatypterygius_(Myopterygius)_kiprijanoffi_rooted_tooth_with_tip_01.thumb.jpg.5859507dc57e27cd09f573faeb022a95.jpgPlatypterygius_tooth_with_root_1.jpg.49ee4f5dcb9f7c03f74141273d6418fd.jpg

I'm really appreciate to your informative comment!

They had conical hollow roots. The next tooth in the jaw would be growing underneath it waiting to erupt. It is the same root system on the Russian tooth. Ichthyosaurs do not have this root system and why I think its possibly pliosaur

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3 hours ago, Kim sung hyun said:

They had conical hollow roots. The next tooth in the jaw would be growing underneath it waiting to erupt. It is the same root system on the Russian tooth. Ichthyosaurs do not have this root system and why I think its possibly pliosaur

 

Though I must confess that I don't quite understand how these roots end up being hollow myself, the images in my previous post show that at least these particular platypterygiine teeth occasionally end up being hollow as well as have a cylindrical neck. Therefore, with the teeth from Stary Oskol you really need to carefully analyse the morphology of the tooth crown rather than the root (unless the latter is complete, in which case a rectangular root clearly points to ichthyosaur). In case of the images you posted, morphology more closely matches that of ophthalmosaurid ichthyosaurs, rather than any known pliosaur.

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