Show Me Your Mosasaurs!

[Halisaurus]

Hello!!! On this topic, I would LOVE to see everybody's mosasaur fossils!!!!!!!!!!!!! 

Here's my Halisaurus (probably) tooth fossil!

[ziggycardon]

While I collect fossils from all geological era's and from all different groups of animals and life, Mosasaurs are my favorites.
 

 

My Proganthodon anceps jaw found in Khourigba, Morocco

 

 

Mosasaur finger bones, radius, and an unidentified tooth from Khouribga, Morocco

 

 

Globidens phosphaticus teeth from Khouribga, Morocco

 

 

A Prognathodon currii tooth and a Mosasaur tail vertebra found in Khouribga, Morocco

 

 

Multiple species of Mosasaur from Khouribga, Morocco

 

 

Mosasaurus hoffmani vertebra found in the Maastricht area in the Netherlands

 

 

Tethyssaurus jaw from Goulmina, Morocco
Multiple Mosasaur vertebrae found in Texas, USA

A Tylosaurus tooth found in Texas, USA

A Mosasaurus tooth found in Bakrit, Morocco

Three teeth from different species found in the Smoky Hill Chalk of Kansas, USA

 

 

[Yoda]

@ziggycardon

That is really nice Mosasaur material 

[North]

Yes. Mosasaurs are my favorites too.

All of mine are from Morocco.

[pachy-pleuro-whatnot-odon]

Indeed! Really nice mosasaur collection, Ken! 

[Kikokuryu]

I'm just getting into collecting mosasaurs, but I have not really nailed down, or fully understood the morphologies of the smaller genera. I have not gotten a big jaw, other than a small partial Tethysaurus like many folks have yet.

 

Starting with the easy IDs

 

Stelladens mysteriosus teeth from the Couche III, Morocco. Quickly became one of my top 10 favorite prehistoric animals.

 

Hainosaurus boubker (left) and Prognathodon currii (right) from the Couche III, Morocco.

 

Tethysaurus nopcsai from the Akrabou Formation, Morocco.

 

Now for the lesser clear stuff, or I just don't know.

 

Blufftown Formation, Russell County, Alabama, USA. The right tooth is Tylosaurus sp. for sure, but I'm not really 100% sure of the left tooth.

 

Left is I think Pluridens serpentis ??? from the Couche III, Morocco. Not sure about the right, it's from the Taylor Group, North Sulphur River, Fannin County, Texas, USA.

 

Christmas Creek, East of Waco, Texas, USA. I have no idea what formation this is supposed to be. Nothing really comes up for Christmas Creek. But I'm guessing a tylosaur???

Edited September 15, 2023 by Kikokuryu

[North]

11 minutes ago, Kikokuryu said:

Hainosaurus boubker (left)

That one looks chunky. Can I ask how big it is?

I have been trying to find Hainosaurus boubker over an year without luck.

[pachy-pleuro-whatnot-odon]

6 minutes ago, Kikokuryu said:

Stelladens mysteriosus teeth from the Couche III, Morocco. Quickly became one of my top 10 favorite prehistoric animals.

 

That's a nice Stelladens mysteriosus! Wish I could get hold of more of those, but they're indeed hard to come by, and I find them rather expensive if you do. I guess they're the new Carinodens, in that sense

 

6 minutes ago, Kikokuryu said:

Tethysaurus nopcsai from the Akrabou Formation, Morocco.

 

Again, not a bad specimen! I've got multiple pieces of Tethysaurus nopscai, yet either have toothless jaws, or pieces with teeth on matrix. None matrix free with quality tooth like these, so definitely a special piece in my book

 

6 minutes ago, Kikokuryu said:

Blufftown Formation, Russell County, Alabama, USA. The right tooth is Tylosaurus sp. for sure, but I'm not really 100% sure of the left tooth.

 

See the fine lines at the base of both teeth here (as well as your Hainosaurus boubker above)? Those are called tertiary striae, and are indicative of tylosaurine teeth. So both of these teeth would classify as Tylosaurus sp., which can also be seen from the curvature of the teeth. Hard to say which species, though my guess would be T. nepaeolicus.

 

6 minutes ago, Kikokuryu said:

Left is I think Pluridens serpentis ??? from the Couche III, Morocco. Not sure about the right, it's from the Taylor Group, North Sulphur River, Fannin County, Texas, USA.

 

The one on the left could indeed be Pluridens serpentis, considering it's size. However, as it lacks the enamel folds around the base typical of these teeth, it could also still very well be a large Halisaurus arambourgi. I'm leaning more towards P. serpentis too, though, seeing as the surface enamel texture, curvature and how some minimal folding does seem to be present when the photograph is scaled down. The one on the right seems to be a plioplatecarpine mosasaur, probably Platecarpus tympanicus.

 

6 minutes ago, Kikokuryu said:

Christmas Creek, East of Waco, Texas, USA. I have no idea what formation this is supposed to be. Nothing really comes up for Christmas Creek. But I'm guessing a tylosaur???

 

With striations like that and especially the somewhat rectangular base, this is not actually a mosasaur tooth, but a fish tooth of Pachyrhizodus sp..

[Kikokuryu]

3 minutes ago, North said:

That one looks chunky. Can I ask how big it is?

I have been trying to find Hainosaurus boubker over an year without luck.

About 2.5" (6.35cm). I think at the bigger sizes, it's easy to separate them from the other big genera like Thalassotitan, Mosasaurus, and Prognathodon. Stelladens also surprisingly produces some big teeth.

[Kikokuryu]

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

With striations like that and especially the somewhat rectangular base, this is not actually a mosasaur tooth, but a fish tooth of Pachyrhizodus sp..

Interesting. Thank you for the IDs. I don't have that genus yet, so that's perfectly fine. Still don't know what formation it is though.

 

Also going to now make some new labels before I forget to do so.

Edited September 15, 2023 by Kikokuryu

[Kikokuryu]

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

See the fine lines at the base of both teeth here (as well as your Hainosaurus boubker above)? Those are called tertiary striae, and are indicative of tylosaurine teeth. So both of these teeth would classify as Tylosaurus sp., which can also be seen from the curvature of the teeth. Hard to say which species, though my guess would be T. nepaeolicus.

Right, I wasn't 100% sure if the left tooth was just eroded in a way that made it look like it had tertiary striae. But taking a closer look under a scope, it does appear to have tertiary striae.

 

[Jared C]

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

With striations like that and especially the somewhat rectangular base, this is not actually a mosasaur tooth, but a fish tooth of Pachyrhizodus sp..

I have seen some associated Clidastes material with a straight-sided base in the teeth. It no longer appears to me these days that the straight-sidedness of a tooth base is actually very diagnostic between Pachyrhizodus and Mosasaurs. 

 

Perhaps size and the assumed presence of an acrodin cap in Pachyrhizodus would be my go-to's, though I've never examined a pachy tooth closely enough to discern an acrodin cap. During my discussions with Mike Polcyn, he also pointed out that mosasaurs as a whole have very thin enamel. If worn, one should be able to see the enamel-dentin interface.  

 

Below are the cross sections of two mosasaur teeth- notice the extremely thin enamel. 

 

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12 hours ago, Kikokuryu said:

Christmas Creek, East of Waco, Texas, USA. I have no idea what formation this is supposed to be. Nothing really comes up for Christmas Creek. But I'm guessing a tylosaur???

 

Fortunately there is wear here, and I'm perceiving thin enamel at the enamel-dentin interface. My vote would personally fall towards mosasaur.

 

But what about striations?

Bell '97 described russelosaurine teeth with with visible striations.

 

Hallie Street et.al also did a great paper of mosasaur tooth morphologies, here:

https://www.researchgate.net/publication/354736370_A_histological_investigation_of_dental_crown_characters_used_in_mosasaur_phylogenetic_analyses

This paper is the origin of the cross section images above as well. 

 

 

Bell's observation of Striation in Russelosaurs holds up here, as is seen with the increased frequency of striations within Russelosaurina. 

 

The general area of the tooth in question supports a maastrichtian age, but campanian is also possible. It's tough to tell without the particular locality. That would make the possible russelosaur origin interesting, with the rarity of the clade during the maastrichtian. But again, hard to tell anything about age for sure given the vague nature of the locale. 

 

 

Edited September 15, 2023 by Jared C

[Halisaurus]

Whoa! You all got really cool mosasaur fossils! Guess I AM a noob at fossils!

Anyways, thank you all for sharing! I’m looking forward to having more comments!