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Mosasaurus hoffmanni tooth?


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Mochaccino

Hello,

 

I have another mosasaur tooth ID question. This is listed as Mosasaurus beaugei from Kem Kem Morocco, on the small side at just over 4.1 cm. Based on what I recall @Praefectus said, is it possible this is actually a M. hoffmanni? It has very few, prominent facets, which are apparently diagnostic to hoffmanni rather than beaugei? @pachy-pleuro-whatnot-odon


Sadly the tooth doesn't seem in the best shape though.


Thanks!

 

EC77033C-2640-40B1-844A-5D9238F80AA7.thumb.jpeg.cf48e1bc27770a08e9ad048cf2f44efc.jpeg43B53FAE-2BB7-482E-AF2E-9314A91962C3.thumb.jpeg.68683e3f94b5f2e80d657603c636a972.jpegABD7BD1B-01EE-417A-857F-4B10C2768AFC.thumb.jpeg.e00e1967b6702bdf2e072996a08af168.jpeg051D3659-FA6D-4E2A-A291-0CA81365065B.thumb.jpeg.90dc22b500cfecaffb4afd98c60da906.jpeg

 

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Jared C

Is this Moroccan?

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Mochaccino
3 minutes ago, Jared C said:

Is this Moroccan?

Yep, listed as Kem Kem Morocco, my bad should've included that info

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Jared C
Just now, Mochaccino said:

Yep, listed as Kem Kem Morocco, my bad should've included that info

no worries. @Praefectus and @pachy-pleuro-whatnot-odon actually worked on a paper recently establishing the range of M. hoffmani going into Morocco, if I remember correctly. They'll know better than anyone.

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siteseer

The Kem Kem beds represent a river deposit but mosasaurs lived in the ocean.  I think someone made a mistake because that looks like a tooth of one of the more advanced mosasaurs from the latest Cretaceous and might belong to M. hoffmanni.  The Kem Kem beds are something like 95-100 million years old and the earliest mosasaurs didn't appear until a few million years later.

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pachy-pleuro-whatnot-odon
3 hours ago, Jared C said:

Is this Moroccan?

 

Yep, this is Moroccan from the Ouled Abdoun Basin, Maastrichtian in age. The deposits that form the Kem Kem group predate the occurrence of even the earliest records of basal mosasaurs in Morocco, such as Tethysaurus nopscai, except for at the very top of the sequence where, however, no mosasaur remains have, to my knowledge, been reported from this carbonate layer.

 

The tooth here indeed belongs to the genus Mosasaurus, though I'd say it's a bit too prismatic for M. hoffmannii, even if certain vendors in the past would've applied this label. Looking at the three specimens in my collection (two of which are figured below after Rempert, Vinkeles Melchers, Rempert, Hague and Armstrong, 2022), their prism faces and facets can barely made out in real life, even if they can still be seen in the photographs:

 

Mosasaurus-hoffmannii-Mantell-1829-from-the-Moroccan-phosphates-D-AVM-01-UCIII.png.75d54590d86bbf08e4011d755bfc1539.png

 

Some other examples from the same publication:

 

Mosasaurus-hoffmannii-Mantell-1829-from-the-Moroccan-phosphates-A-REMPC-M0001-UCIII.thumb.png.3c093f392028e1481d901c2c717ed52f.png

 

Mosasaurus-hoffmannii-Mantell-1829-F-CORN-01-in-anterior-F1-labial-F2-posterior.png.96f6f6fdabb2e1df50e34125a56e7884.png

 

In conclusion, I think this tooth is Mosasaurus beaugei. A lingual facet count might help, though, although I doubt this is/will be available...

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Mochaccino
4 hours ago, Jared C said:

no worries. @Praefectus and @pachy-pleuro-whatnot-odon actually worked on a paper recently establishing the range of M. hoffmani going into Morocco, if I remember correctly. They'll know better than anyone.

 

3 hours ago, siteseer said:

The Kem Kem beds represent a river deposit but mosasaurs lived in the ocean.  I think someone made a mistake because that looks like a tooth of one of the more advanced mosasaurs from the latest Cretaceous and might belong to M. hoffmanni.  The Kem Kem beds are something like 95-100 million years old and the earliest mosasaurs didn't appear until a few million years later.

 

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

 

Yep, this is Moroccan from the Ouled Abdoun Basin, Maastrichtian in age. The deposits that form the Kem Kem group predate the occurrence of even the earliest records of basal mosasaurs in Morocco, such as Tethysaurus nopscai, except for at the very top of the sequence where, however, no mosasaur remains have, to my knowledge, been reported from this carbonate layer.

 

The tooth here indeed belongs to the genus Mosasaurus, though I'd say it's a bit too prismatic for M. hoffmannii, even if certain vendors in the past would've applied this label. Looking at the three specimens in my collection (two of which are figured below after Rempert, Vinkeles Melchers, Rempert, Hague and Armstrong, 2022), their prism faces and facets can barely made out in real life, even if they can still be seen in the photographs:

 

Mosasaurus-hoffmannii-Mantell-1829-from-the-Moroccan-phosphates-D-AVM-01-UCIII.png.75d54590d86bbf08e4011d755bfc1539.png

 

Some other examples from the same publication:

 

Mosasaurus-hoffmannii-Mantell-1829-from-the-Moroccan-phosphates-A-REMPC-M0001-UCIII.thumb.png.3c093f392028e1481d901c2c717ed52f.png

 

Mosasaurus-hoffmannii-Mantell-1829-F-CORN-01-in-anterior-F1-labial-F2-posterior.png.96f6f6fdabb2e1df50e34125a56e7884.png

 

In conclusion, I think this tooth is Mosasaurus beaugei. A lingual facet count might help, though, although I doubt this is/will be available...

 

Thank you all, yes then I figure the seller-provided locality is wrong. Wow I actually wasn't aware @Praefectus and @pachy-pleuro-whatnot-odon had worked on this paper, amazing! From those figures it looks like there is more to it than just # of facets, they do look much more rounded than prismatic. I mainly just have online listings to compare to so this is very helpful. So this specimen is more a beaugei with a lower # of facets then, thanks.

 

 

 

 

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Praefectus

EC77033C-2640-40B1-844A-5D9238F80AA7.thumb.jpeg.cf48e1bc27770a08e9ad048cf2f44efc.jpeg.d1168e2249ad603eb241a78164a87df2.jpeg

 

This tooth is Mosasaurus beaugei from the Moroccan Phosphates. The facets are more prominent and numerous than in M. hoffmannii. The teeth of M. beaugei are generally thinner and less robust than those of M. hoffmannii too. Kem Kem is too early for Mosasaurus. Mosasaur ancestors were only just returning to sea around the Cenomanian-Turonian. 

 

Facet (prism) counts can be used to differentiate the species. Generally, M. beaugei has 3-5 labial, 8-9 lingual facets. M. hoffmannii has 2-3 labial, <5 lingual facets. The lingual facet count for M. hoffmannii is approximate because they are sometimes so poorly defined that they cannot be counted. 

20220729_083200.jpg.a34ddbd5322bb0620dd66abc1dc7fbc0.jpg

 

20220729_083248.jpg.22f03b60fc9e43f23aa3db208e086c26.jpg

 

5 hours ago, Mochaccino said:

So this specimen is more a beaugei with a lower # of facets then, thanks.

Other way around. It is M. beaugei because of a higher number of facets. :Smiling:

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Mochaccino
Posted (edited)
7 hours ago, Praefectus said:

EC77033C-2640-40B1-844A-5D9238F80AA7.thumb.jpeg.cf48e1bc27770a08e9ad048cf2f44efc.jpeg.d1168e2249ad603eb241a78164a87df2.jpeg

 

This tooth is Mosasaurus beaugei from the Moroccan Phosphates. The facets are more prominent and numerous than in M. hoffmannii. The teeth of M. beaugei are generally thinner and less robust than those of M. hoffmannii too. Kem Kem is too early for Mosasaurus. Mosasaur ancestors were only just returning to sea around the Cenomanian-Turonian. 

 

Facet (prism) counts can be used to differentiate the species. Generally, M. beaugei has 3-5 labial, 8-9 lingual facets. M. hoffmannii has 2-3 labial, <5 lingual facets. The lingual facet count for M. hoffmannii is approximate because they are sometimes so poorly defined that they cannot be counted. 

20220729_083200.jpg.a34ddbd5322bb0620dd66abc1dc7fbc0.jpg

 

20220729_083248.jpg.22f03b60fc9e43f23aa3db208e086c26.jpg

 

Other way around. It is M. beaugei because of a higher number of facets. :Smiling:


Very informative, thank you! I should clarify that last part, I meant that this is a M. beaugei, but with a lower than typical number of facets. This might just be my untrained eye but it looks to me that the labial side only has 3 large facets, granted they are prominently defined. This was really why I initially thought this tooth might be a hoffmanni. But I guess 3 still falls in the range of 3-5 labial facets of beaugei, just the lower end. Unfortunately from seller-provided photos it's hard to see lingual facets, but in this case it seems the beaugei diagnosis comes from how strongly-defined the facets are.

 

0E9B6413-0740-42EE-BD5D-87974AB80D31.thumb.jpeg.ab55313efcc9a39ddf81b39e56a4edc0.jpeg9ECEFFC9-D5DA-43C5-A205-BDF80AFBAE8F.thumb.jpeg.06be0a76143a238f8b6a39897c4acf41.jpeg

Edited by Mochaccino
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pachy-pleuro-whatnot-odon
1 hour ago, Mochaccino said:

I meant that this is a M. beaugei, but with a lower than typical number of facets. This might just be my untrained eye but it looks to me that the labial side only has 3 large facets, granted they are prominently defined. This was really why I initially thought this tooth might be a hoffmanni. But I guess 3 still falls in the range of 3-5 labial facets of beaugei, just the lower end.

 

All things considered, 3 prism faces is just about as much as an outlier for M. beaugei as it is for M. hoffmannii, even if it forms the lower boundary for the first, whereas it forms the upper limit for the other.

 

But, yeah, smoothness of the tooth's geometric shape does play a role in identification - which is why it can be easy to confuse the one species for the other...

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Mochaccino
42 minutes ago, pachy-pleuro-whatnot-odon said:

 

All things considered, 3 prism faces is just about as much as an outlier for M. beaugei as it is for M. hoffmannii, even if it forms the lower boundary for the first, whereas it forms the upper limit for the other.

 

But, yeah, smoothness of the tooth's geometric shape does play a role in identification - which is why it can be easy to confuse the one species for the other...

 

I see, so a borderline specimen in terms of facet number. I suppose a good specimen to learn the finer species distinctions from! Quite confusing these two.

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pachy-pleuro-whatnot-odon
14 minutes ago, Mochaccino said:

I see, so a borderline specimen in terms of facet number. I suppose a good specimen to learn the finer species distinctions from! Quite confusing these two.

 

They can be and commercially often are confused. I've bought specimens, from renowned dealers, advertised as M. hoffmannii that turned out to, like this specimen, be M. beaugei, whereas my first confirmed and overall highest quality M. hoffmannii was identified as M. beaugei by the seller...

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

 

They can be and commercially often are confused. I've bought specimens, from renowned dealers, advertised as M. hoffmannii that turned out to, like this specimen, be M. beaugei, whereas my first confirmed and overall highest quality M. hoffmannii was identified as M. beaugei by the seller...

 

I can see that happening for sure! No wonder I'm confused. The paper by you and @Praefectus will no doubt be very helpful moving forward :)

 

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Praefectus
18 hours ago, Mochaccino said:

Very informative, thank you! I should clarify that last part, I meant that this is a M. beaugei, but with a lower than typical number of facets. This might just be my untrained eye but it looks to me that the labial side only has 3 large facets, granted they are prominently defined. This was really why I initially thought this tooth might be a hoffmanni. But I guess 3 still falls in the range of 3-5 labial facets of beaugei, just the lower end. Unfortunately from seller-provided photos it's hard to see lingual facets, but in this case it seems the beaugei diagnosis comes from how strongly-defined the facets are.

 

I think this tooth has 4 labial facets. The fourth one is just very hard to make out from the picture provided. 

0E9B6413-0740-42EE-BD5D-87974AB80D31.thumb.jpeg.ab55313efcc9a39ddf81b39e56a4edc0.jpeg.2ddcc960a2af96a438a44708475682ea.jpeg

 

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

They can be and commercially often are confused. I've bought specimens, from renowned dealers, advertised as M. hoffmannii that turned out to, like this specimen, be M. beaugei, whereas my first confirmed and overall highest quality M. hoffmannii was identified as M. beaugei by the seller...

I still get them confused. It is so easy for picture quality to hide an important detail. 

 

It also doesn't help that some dealers will label every mosasaur tooth they see as M. hoffmannii:blink:

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