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Hello.

I got this tooth from an old collection .

On the info card it says its a Dakosaurus tooth from Cap Gris Nez France.

Period kimmeridgian.

So is this an Dakosaurus tooth? 

Thanks

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pachy-pleuro-whatnot-odon

Definitely looks like the tooth of a large metriorhynchid crocodile, and Dakosaurus is known from that location - with the adhering matrix suggesting that the location information is correct as well. It'll be difficult to fully confirm it, as the tooth is so damaged, and somewhat worn. However, on the whole I'd say, yes, this is a Dakosaurus sp. tooth. Very nice! Still hope to add one of those from that location to my collection as well! :default_clap2:

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Thanks .

I looked on the internet but couldn't find allot of information or teeth like this.

Is this a rare tooth? Also i got a Machimosaurus tooth  from the same place to .

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pachy-pleuro-whatnot-odon

Unfortunately, I too find that information on French fossils, and amongst those, vertebrates in particular, is hard to come by, the fossils from Cap Gris Nez bring no exception. The site Fossiles jurassique Boulonnais, in that respect, is an excellent resource for such fossils. The below two images of Dakosaurus-teeth, for example, were taken from that site, and would seem to form a good match with your specimen:

 

919097834_DakosaurustoothBoulonnais02.jpg.e439fe11f7eb5c8d56b5f829c9252e87.jpg

 

699345326_DakosaurustoothBoulonnais01.jpg.754dda6036b99dba3fc420454bbb498d.jpg

 

Other good places to mom for information on French fossils in particular are French fossil forums, such as Geoforum, where I found the below metriorhynchid tooth (observe the difference in ornamentation with diagnostic facetting near the base of the tooth crown):

 

547519169_MetriorhynchidtoothBoulonnais.jpg.0060d67db14b1db320299e8bffa03493.jpg

 

As to how common or rare such teeth are, I really wouldn't know, as I've only ever been to the Boulonnais once myself. From a contact of mine, however, and updates on fossil finds in the region, I understand that while finds of marine reptile bones are not particularly rare - with finds of crocodile material predominating - he himself has only once found a partial tooth across multiple years of frequent trips. Thus, I'd say they're not very common, though crocodile teeth are more common than those of other marine reptiles. And going by Fossiles jurassiques Boulonnais, it looks like, much as in other locations, teeth of Machimosaurus are rarer than other crocodile species (would love to see a picture of your specimen, by the way ;))...

 

Hope this helps!

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Here are some photos. Last 2 are from a plesiosaur from  same place .

Thanks al the information helps

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pachy-pleuro-whatnot-odon

Those are some very nice teeth... as is the Dakosaurus! You've been very lucky to pick these up! :envy:

 

I think the last one is not a machimosaurid, though, even if it is a teleosaurid, since it's not robust enough nor have any of the durophagous adaptations seen in Machimosaurus... Instead, I suspect it's a Steneosaurus sp., much like the one in the image below (source):

 

21684754_Steneosaurussp.toothBoulonnais.jpg.836f595929eb96b8c5aed6c0942b0e66.jpg

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Thanks. The first 4 photos the card said machimosaurus and the last 2 photos the card said plesiosaur. But the steneosaurus tooth also looks like it . I like the teeth but i collect mainly collect spinosaur en carcharodontosaurus teeth

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

Thanks. The first 4 photos the card said machimosaurus and the last 2 photos the card said plesiosaur. But the steneosaurus tooth also looks like it . I like the teeth but i collect mainly collect spinosaur en carcharodontosaurus teeth

 

Well, if you ever think of passing them on, just let me know then, because my main interest lies with marine reptiles ;)

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Ok thanks . I think i will let them go but only for a good offer. 

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Manticocerasman

I agree with the Id's from "Pachy-pleuro"

1st. Dakosaur

2nd. Machimosaurus

3rd . probably Steneosaurus , Plesiosaur is also an option but it is almost impossible to make the difference between isolated Steneosaurus and Plesiosaurus teeth .

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

3rd . probably Steneosaurus , Plesiosaur is also an option but it is almost impossible to make the difference between isolated Steneosaurus and Plesiosaurus teeth .

 

I wouldn't say so... Crocodilian teeth have carinae, as does Steneosaurus, whereas plesiosaur teeth don't. Also, with the exception of pliosaurs and possibly early (read: Triassic) plesiosaurs, plesiosaur teeth don't have as strong striations on the labial side as this specimen (second photograph) shows. The photograph could've been better, but since a clear carina can be seen towards the less worn top of the tooth in the second photograph (and not an apicobasal ridge as some pliosaurs and polycotylids have) and there are striations on the labial side, I'd say this is a teleosaurian tooth. It's moreover not robust enough for pliosaur, just to rule that out. Plesiosaur teeth from this region would look more like the below (an almost elasmosaurian-like tooth cf. Muraenosaurus sp. on the left, a more typical plesiosaur tooth from this location - one I'd class as pliosaur - on the right; source 1, 2):

 

764563968_Cf.MuraenosaurustoothfromtheBoulonnais.jpg.bc7ac8ab79e0d4554d89bdf328aa3d92.jpg759747893_PlesiosauriantoothfromtheBoulonnais.jpg.abcdbac76873995a4dfabfcef1e3ddf0.jpg

 

 

Compare to second tooth to the below the Liopleurodon ferox tooth from Hildesheim in Germany, described by Sven Sachs:

Liopleurodon.thumb.jpg.1d07b9ac8723865b983ac809cfe112a4.jpg

 

 

I myself own a similar tooth from the Boulonnais, as shown below, which has a very similar morphology to the teeth of rhomaleosaurids, which I take as additional support for such teeth indeed being pliosaurid:

 

tithonian_jurassic_pliosaur_tooth_base_01.thumb.jpg.a5b51cb2052affea791f5a1ad1ec7775.jpgtithonian_jurassic_pliosaur_tooth_base_02.thumb.jpg.7534d972ff565f9191e20e58b1d8be12.jpgtithonian_jurassic_pliosaur_tooth_base_06.thumb.jpg.55b8eebbc5618828c63c0d132579de1e.jpgtithonian_jurassic_pliosaur_tooth_base_04.thumb.jpg.442cdb6e2e9b3e5e9815e810240408f3.jpgtithonian_jurassic_pliosaur_tooth_base_03.thumb.jpg.95f09eb767152ef76c98dd97b89728d2.jpgtithonian_jurassic_pliosaur_tooth_base_05.thumb.jpg.b45d5cfcd9857e714f22b75e4189908a.jpg

 

 

Fossiles Jurassique Boulonnais, however, only considers the most robust and distinctly striated specimens pliosaurid:

 

537823423_PliosaurtoothfromtheBoulonnais.jpg.8999951b52c9f7e1ba4ea082f6368fd8.jpg

 

Edited by pachy-pleuro-whatnot-odon
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Manticocerasman
4 minutes ago, pachy-pleuro-whatnot-odon said:

 

I wouldn't say so... Crocodilian teeth have carinae, as does Steneosaurus, whereas plesiosaur teeth don't. Also, with the exception of pliosaurs and possibly early (read: Triassic) plesiosaurs, plesiosaur teeth don't have as strong striations on the labial side as this specimen (second photograph) shows. The photograph could've been better, but since a clear carina can be seen towards the less worn top of the tooth in the second photograph (and not an apicobasal ridge as some pliosaurs and polycotylids have) and there are striations on the labial side, I'd say this is a teleosuchian tooth. It's moreover not robust enough for pliosaur, just to rule that out. Plesiosaur teeth from this region would look more like the below (an almost elasmosaurian-like tooth cf. Muraenosaurus sp. on the left, a more typical plesiosaur tooth from this location - one I'd class as pliosaur - on the right; source 1, 2):

 

764563968_Cf.MuraenosaurustoothfromtheBoulonnais.jpg.bc7ac8ab79e0d4554d89bdf328aa3d92.jpg759747893_PlesiosauriantoothfromtheBoulonnais.jpg.abcdbac76873995a4dfabfcef1e3ddf0.jpg

 

 

Compare to second tooth to the below the Liopleurodon ferox tooth from Hildesheim in Germany, described by Sven Sachs:

Liopleurodon.thumb.jpg.1d07b9ac8723865b983ac809cfe112a4.jpg

 

 

I myself own a similar tooth from the Boulonnais, as shown below, which has a very similar morphology to the teeth of rhomaleosaurids, which I take as additional support for such teeth indeed being pliosaurid:

 

tithonian_jurassic_pliosaur_tooth_base_01.thumb.jpg.a5b51cb2052affea791f5a1ad1ec7775.jpgtithonian_jurassic_pliosaur_tooth_base_02.thumb.jpg.7534d972ff565f9191e20e58b1d8be12.jpgtithonian_jurassic_pliosaur_tooth_base_06.thumb.jpg.55b8eebbc5618828c63c0d132579de1e.jpgtithonian_jurassic_pliosaur_tooth_base_04.thumb.jpg.442cdb6e2e9b3e5e9815e810240408f3.jpgtithonian_jurassic_pliosaur_tooth_base_03.thumb.jpg.95f09eb767152ef76c98dd97b89728d2.jpgtithonian_jurassic_pliosaur_tooth_base_05.thumb.jpg.b45d5cfcd9857e714f22b75e4189908a.jpg

 

 

Fossiles Jurassique Boulonnais, however, only considers the most robust and distinctly striated specimens pliosaurid:

 

537823423_PliosaurtoothfromtheBoulonnais.jpg.8999951b52c9f7e1ba4ea082f6368fd8.jpg

 

 

I'll have to check with the literature that I have from The Boulonais.

I've found a tooth there last year that could either be plesio or Steneosaur, no one was able to give me a propper id on it. 

mabey you could help me with it, I'll send a picture to you in pm. I have an old publication on marine reptiles from that area where they noted that the distinction couldn't be made from isolated teeth, but then again it could be outdated. (If I find the pdf version, I'll send you a copy )

 

cheers,

Kevin

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Manticocerasman

There are also mentions of Steneosaurids without carinae in "Les Dinosauriens et Crocodiliens des terrains Jurassique de Boulogne-sur-mer"  from the Mémoires de la Sociéte Géologique de France. but then again it is a very old publication. 

 

 

132223009_Schermafbeelding2021-11-10132858.png.c68328558d5bbefa8b1c445e2c65ddf5.png

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Manticocerasman

this is the publication where I've read that isolated Steneosaur and plesiosaur teeth couldn't be differentiated.  ( Page 15 )

 

https://www.researchgate.net/publication/311695278_Vadet_Alain_Vadet_Alexandre_Lenoir_L_1997_Guide_de_determination_des_reptiles_fossiles_du_Boulonnais_Kimmeridgien_et_Tithonien

 

It is a nice guide for vertebrate material from the Boulonais.

 

 

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pachy-pleuro-whatnot-odon
On 11/10/2021 at 2:27 PM, Manticocerasman said:

this is the publication where I've read that isolated Steneosaur and plesiosaur teeth couldn't be differentiated.  ( Page 15 )

 

https://www.researchgate.net/publication/311695278_Vadet_Alain_Vadet_Alexandre_Lenoir_L_1997_Guide_de_determination_des_reptiles_fossiles_du_Boulonnais_Kimmeridgien_et_Tithonien

 

It is a nice guide for vertebrate material from the Boulonais.

 

Thanks for sharing the link! Glancing it over it indeed looks like a very informative publication! :thumbsu:

 

On 11/10/2021 at 1:35 PM, Manticocerasman said:

There are also mentions of Steneosaurids without carinae in "Les Dinosauriens et Crocodiliens des terrains Jurassique de Boulogne-sur-mer"  from the Mémoires de la Sociéte Géologique de France. but then again it is a very old publication. 

 

 

132223009_Schermafbeelding2021-11-10132858.png.c68328558d5bbefa8b1c445e2c65ddf5.png

 

That Sericodon sounds like a very peculiar teleosaurid, then, as all teleosaurian teeth I've seen (cf. TeleosaurusSteneosaurusSeldsienianMachimosaurus and a Bajocian teleosauridae indet.) are double-carinated. It seems that it's still a valid taxa, however, as it was revived in 2020, after a period of inclusion in SteneosaurusSteneosaurus, on the other hand, has become as it not a problematic name, since it has long been used as a wastebasket taxon, and many of its flourishing species have since been split off into their own genera (see Johnson, Young and Brusatte, 2020)...

 

On 11/10/2021 at 1:22 PM, Manticocerasman said:

I have an old publication on marine reptiles from that area where they noted that the distinction couldn't be made from isolated teeth, but then again it could be outdated.

 

As to the matter of being able to tell a plesiosaur from a crocodile tooth, it indeed used to be the case that most researchers considered teeth unsuitable for taxonomic classification. And while this sentiment is still very much alive (and with reasonably good reason), much has been done in recent years to improve the taxonomic value of teeth (e.g., Foffa, Young and Brusatte, 2018):  studies have looked into how to distinguish marine reptile classes from one another on how to identify teeth within these clades as to genus and species. Even in the field of mosasaur research, traditionally probably the most strongly opposed to taxonomies based on teeth due to mosasaur heterodonty, entire new species have now been erected based on isolated tooth finds.

 

I myself also belong to the camp that believes there's certain taxonomic value to marine reptile teeth, although I do maintain my reservations as to how far one can take this approach. For it can sometimes indeed be very tricky to tell a plesiosaur from a teleosaur tooth, though, if the teeth are sufficiently well-preserved, there mostly is enough distinction between the clades to do separate them without much effort. I don't agree with the statement on page 15 of your publication, for example, as they explicitly mention the difficulty in distinction being between Muraenosaurus and Steneosaurus. However, the teeth of Steneosaurus have a round cross-section, are double-carinated and near fine, but pronounced parallel striae. Those of Muraenosaurus, on the other hand, don't bear carinae, are labiolingually compressed, and have fine striations only on the lingual side, the other side being smooth (see below images).

 

601de60e87bca_oxfordclayplesiosaurteeth.jpg.f8aa95899493a585be843e6c31ce2ff9.jpg

Cryptoclidid plesiosaur teeth from the Oxford Clay: Muraenosaurus leedsi (left), Cryptoclidus oxoniensis (middle), Tricleidus seeleyi (right) (Noè, Taylor and Gómez-Pérez, 2017).

 

601de6ac57d5c_Muraenosaurusleedsiplesiosaurtooth.jpg.df2ebe37b7a5f42f71422a27ebecfba8.jpg

Muraenosaurus leedsi from the Oxford Clay of Peterborough

 

764563968_Cf.MuraenosaurustoothfromtheBoulonnais.jpg.bc7ac8ab79e0d4554d89bdf328aa3d92.jpg

Muraenosaurus sp. from the Boulonnais (same as above; source)

 

Compare against the tooth morphology of various 'Steneosaurus' species taken from Mueller-Töwe (2006) below:

 

350182436_Steneosaurusspp.teeth.thumb.jpg.6bf8502f37b28570d98fa4fe2d1270f0.jpg

 

In other words, of the above Oxford Clay species, the only one that could potentially cause confusion with crocodile teeth would be Tricleidus. However, even these teeth are easy to differentiate due to the prominence of the striae in the plesiosaurian teeth, as well as the absence of carinae (see below; source).

 

106510977_Cf.Tricleidussp.fromtheBoulonnais.jpg.6a8aeca0dc5dc0dee9a4f9fcb022171f.jpg

 

However, as the deposits in the Boulonnais are Kimmeridge Clay (Kimmeridgian/Tithonian rather than Callovian/Oxfordian), we should not forget to evaluate plesiosaurs specific to this timeframe: Colymbosaurus and Kimmerosaurus. Colymbosaurus, however, has narrow subtrihedral teeth with strong striations (see image below; source). And while I don't quite know how the teeth of Kimmerosaurus are supposed to look, one can expect them to be quite narrow (as it's the plesiosaur with the highest tooth count of the time) and not have carinae (as no plesiosaur species has these)...

 

1971711770_ColymbosaurusteethEtchesCollection.thumb.jpg.9598c80b6ca5311808f2285c3bc11263.jpg

 

I hope this helps clarify things a bit...

Edited by pachy-pleuro-whatnot-odon
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pachy-pleuro-whatnot-odon
On 11/10/2021 at 11:38 AM, Manticocerasman said:

3rd . probably Steneosaurus , Plesiosaur is also an option but it is almost impossible to make the difference between isolated Steneosaurus and Plesiosaurus teeth .

 

So it seems I need to come back on my staunch identification of the third tooth as Steneosaurus, and admit Kevin was right when he expressed reservations as to the identification of the tooth as crocodilian rather than plesiosaurian. For now that that I've been able to study the specimen with my own eyes and hold it in my own hands, I have to concede the tooth is indeed plesiosaurian, being attributable to Tricleidus sp..

 

As such, I still believe it's possible to differentiate between teleosaurian and plesiosaurian teeth, but great care must be taken in studying their morphology and ornamental characteristics. For, both 'Steneosaurus' and Tricleidus have very fine striations spanning the circumference of their teeth, with them being present both labially and lingually. However, the teleosaurian teeth bear mesial and distal carinae, whereas the teeth of Tricleidus do not. This particular specimen has a strong apicobasal ridge on one side of the tooth that's easily mistaken for a carina - as I did based on the original photographs - but is not one. The striations on this tooth also don't run the full apicobasal height of the crown, leaving part of the apex smooth and undecorated - something again not readily seen on the supplied photographs, and, in fact, hard to spot in this specimen, even with magnification. This is a characteristic of Tricleidus, but it of teleosaurs, where most striae reach the very apex of the tooth. The Tricleidus tooth is also somewhat laterally compressed, which teleosaur teeth aren't, meaning that to make a proper distinction, not only are clear pictures of medical and distal views needed, one should also be able to look at the tooth's cross-section from the base. The most conclusive evidence for this tooth being plesiosaurian, however, was found in the spot where the one would-be carina is missing. For, instead of another apicobasal ridge, this area shows a bifurcation of striations (one group of striations splitting off to the left, the other to the right), something you'd never see on a teleosaur tooth (and wasn't figured in the available photographs). I've put together the below image to illustrate the above points.

 

1296831239_TricleidusseeleyiCapGrisNezdiagnostics.thumb.jpg.f3db2fc8f90415116093f53e244c59f0.jpg

 

As an interesting aside, the tooth has an S-curve, which I've heard tell about before that certain plesiosaur teeth have, but have never confidently identified in a plesiosaur tooth myself before (although this tooth is heavily repaired, thus the curve might still be an artefact of the repairs). All in all, though, this tooth has been an eye-opener that has since allowed me to identify another misidentified plesiosaur tooth in my collection...

Edited by pachy-pleuro-whatnot-odon
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fifbrindacier

Hi neighbour,  those are very nice teeth, indeed !

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