American Mosasaurs - Information needed

[North]

I believe I have made quite well with collecting Moroccan mosasaurs, so I wish to set my eyes for new goals. And first US mosasaur material is already heading its way.

 

I have been hoping to learn more about American mosasaurs in general and also basic tooth characteristic of more common species.

 

Only one Im relatively familiar with is Tylosaurus proriger. With Platecarpus tympaniticus only by few articles.

 

I managed to find information about most formations where material seem to come from, but not Ozan fm.

What species were present besides Tylosaurus proriger?

 

Thanks for replies.

[Praefectus]

1 hour ago, North said:

What species were present besides Tylosaurus proriger?

Platecarpus, Clidastes, Tylosaurus are the three that are traditionally depicted co-occurring. A few other plioplatecarpines and assorted critters were also sympatric. 

[doushantuo]

Let's not forget Sarabosaurus dahli ( Turonian,Tropic Shale )

Edited March 16 by doushantuo

[North]

2 hours ago, Praefectus said:

Platecarpus, Clidastes, Tylosaurus are the three that are traditionally depicted co-occurring. A few other plioplatecarpines and assorted critters were also sympatric. 

Thanks for reply.

Then it seems to be fairly consistent.

 

Have I understood correctly what comes to their teeth and should there be something good to know for id?

 

Tylosaurus, possibly large teeth, no curvature to the side, tertiary striations.

 

Platecarpus, someway similar than Gavialimimus teeth? Ridges around the tooth?

 

With Clidastes I could only find description: Clidastes teeth are bicarnate(?), laterally compressed and are covered with a smooth enamel (Russell, 1967).

 

[North]

1 hour ago, doushantuo said:

Let's not forget Sarabosaurus dahli ( Turonian,Tropic Shale )

I have not heard that one before.

Thanks for mentioning.

[JamieLynn]

This is Lance's North Texas Fossils website, many mosasuars and various material have been collected in the Ozan Formation in the North Sulphur River. You could use that as a starting point. https://northtexasfossils.com/reptilia2.htm  I have a Tylosaurus tooth that was gifted to me from the NSR. I am interested in finding out what you learn about the distinctions between the teeth as that is something I have tried to research but have come up short on. 

 

Also, @Jared C has been working on a variety of mosasaur finds...he can probably give you lots of info. 

 

 

 

 

[North]

19 minutes ago, JamieLynn said:

This is Lance's North Texas Fossils website, many mosasuars and various material have been collected in the Ozan Formation in the North Sulphur River. You could use that as a starting point. https://northtexasfossils.com/reptilia2.htm  I have a Tylosaurus tooth that was gifted to me from the NSR. I am interested in finding out what you learn about the distinctions between the teeth as that is something I have tried to research but have come up short on. 

 

Also, @Jared C has been working on a variety of mosasaur finds...he can probably give you lots of info. 

 

Thank you for the link.

It seemed that information is sometimes really under the rock.

Ones that I managed to find was mostly from Kansas, but its hard to know for sure is it all correct or possibly outdated. What seemed to be a thing with Moroccan mosasaurs.

I wish I could someday see some material by my own eyes.

 

That seems like nice good sized tooth. 

[Praefectus]

2 hours ago, JamieLynn said:

This is Lance's North Texas Fossils website, many mosasuars and various material have been collected in the Ozan Formation in the North Sulphur River. You could use that as a starting point. https://northtexasfossils.com/reptilia2.htm  I have a Tylosaurus tooth that was gifted to me from the NSR. I am interested in finding out what you learn about the distinctions between the teeth as that is something I have tried to research but have come up short on. 

 

ooooh! That's a pretty Tylosaurus tooth!

[Jared C]

There is a lot of undescribed diversity in the Ozan formation. Quite a few taxa are represented by isolated elements and undescribed, sitting in collections at universities and museums, but I do not think it is my place to name drop them since some are being worked on currently by others. 

 

The "classics" in the NSR and Ozan fm of other places include:

- Tylosaurus proriger (most common)

- Globidens alabamensis (definitely uncommon)

- Latoplatecarpus sp. - (somewhat common). Both described species (L. willistoni and L. nichollsae) lived during the lower and middle campanian, when the Ozan fm was deposited, so both probably occur in the Ozan. L. nichollsae is formally described from at least from Wyoming, South Dakota, and Alabama, while L. willistoni is formally described from at least Manitoba. But, the geographic "ranges" are not as important as the temporal ranges - many Campanian critters from other formations like the Pierre shale or Mooreville chalk are also likely to be found in the Ozan, since all were deposited at the same time. Here are two Latoplatecarpus specimens from the Ozan fm right here on TFF. 

and:

 

 

While these are the big 3, other taxa that one can find include Clidastes, like the one found by @Titan, Plioplatecarpus (found by a collector friend not on the forum), and many, many others that are not described yet. Fortunately, I know a few folks are working on papers about some unseen Ozan critters, so soon we'll know more. 

 

Here's a pdf of a great paper for Mosasaur tooth crown identification:

 

Street+et+al+2021+mosasaur+tooth+histology.pdf

[Praefectus]

8 hours ago, Jared C said:

- Globidens alabamensis (definitely uncommon)

 

Polcyn's got a massive collection of these that he's never published on. I swear, why do collectors keep donating them to him? Complete skulls, juveniles, teeth galore. The most I've seen written on them is an abstract at one of the past mosa meetings (possibly a book chapter too). 

 

8 hours ago, Jared C said:

L. willistoni and L. nichollsae

I've seen willistoni. Wasn't sure the other was there too. 

 

8 hours ago, Jared C said:

Here's a pdf of a great paper for Mosasaur tooth crown identification:

That's the worst paper for mosasaur tooth crown id (I'm not biased). Histology should never supplant gross morphology. The definitions for facet/striation/flute don't agree with what any of the Europeans are publishing. Also, the recommendation to modify character matrices to only recognize presence/absence of enamel ornamentation is downright manipulative. Yeah, let's ignore 200 years of recognizing variation in ornamentation structure so that we can parse down the character entries on the phylogenetic tree. Surely, that predetermined conclusion doesn't preferentially support one person's interpretation of mosa phylogenetics over another's. 

[North]

9 hours ago, Jared C said:

There is a lot of undescribed diversity in the Ozan formation. Quite a few taxa are represented by isolated elements and undescribed, sitting in collections at universities and museums, but I do not think it is my place to name drop them since some are being worked on currently by others. 

 

The "classics" in the NSR and Ozan fm of other places include:

- Tylosaurus proriger (most common)

- Globidens alabamensis (definitely uncommon)

- Latoplatecarpus sp. - (somewhat common). Both described species (L. willistoni and L. nichollsae) lived during the lower and middle campanian, when the Ozan fm was deposited, so both probably occur in the Ozan. L. nichollsae is formally described from at least from Wyoming, South Dakota, and Alabama, while L. willistoni is formally described from at least Manitoba. But, the geographic "ranges" are not as important as the temporal ranges - many Campanian critters from other formations like the Pierre shale or Mooreville chalk are also likely to be found in the Ozan, since all were deposited at the same time. Here are two Latoplatecarpus specimens from the Ozan fm right here on TFF. 

and:

 

 

While these are the big 3, other taxa that one can find include Clidastes, like the one found by @Titan, Plioplatecarpus (found by a collector friend not on the forum), and many, many others that are not described yet. Fortunately, I know a few folks are working on papers about some unseen Ozan critters, so soon we'll know more. 

 

Here's a pdf of a great paper for Mosasaur tooth crown identification:

 

Street+et+al+2021+mosasaur+tooth+histology.pdf 5.99 MB · 3 downloads

Thank you.

Hopefully we learn more about secrets that are in there.

 

This actually makes me think that perhaps some teeth I have seen online could have been Latoplatecarpus instead Platecarpus, but its hard to see much details from small online pictures anyways.

[Jared C]

7 hours ago, Praefectus said:

Polcyn's got a massive collection of these that he's never published on.

In the last 15 years SMU has grown the best Globidens collection in the state for sure. Many folks who hunt the NSR go there first. To be fair on the guy, he and Lively are basically the only two Texans dedicated to mosasaurs right now, and Polcyn has some bigger projects he’s involved in at the moment. Fortunately, he’s also helping out new students who are coming to the scene so there are reinforcements in the future  

 

8 hours ago, Praefectus said:

That's the worst paper for mosasaur tooth crown id (I'm not biased). Histology should never supplant gross morphology.

informative take, I was reeled in by those lovely flashy graphics but didn’t take the time to sit with it for any reason besides ID’ing. Do you have any comprehensive tooth ID papers you’d suggest?

[Jared C]

7 hours ago, North said:

This actually makes me think that perhaps some teeth I have seen online could have been Latoplatecarpus instead Platecarpus, but its hard to see much details from small online pictures anyways.

P. tympaniticus has been formally reported from both the Pierre shale and Mooreville chalk, Campanian formations roughly equivalent to the Ozan, so it coexisted temporally with Latoplatecarpus. I know of a couple Texas specimens of Platecarpus that all come from the Austin chalk, but based on its temporal range elsewhere, it should definitely also be in the Ozan

[eboe101]

I have hunted the ozan for a few decades and have discussed the mosasaur fauna with a few experts. As others have said, publications are extremely limited and it was a high point in Mosasaur evolution. I took down some notes from their notes, in which they think at the least is found in tbe ozan of Texas, as they have posted on the forum and in the DPS facebook site:

 

Angolasaurus

Clidastes Propython

Globidens Alabamaensis

Halisaurus Platyspondylus

Latoplatecarpus

Mosasaurus (Conodon vs Missouriensis)

Platecarpus Coryphaeus

Platecarpus Icericus/Planfrons

Platecarpus Tympaniticus

Plioplatecarpus sp

Russellosaurine (unnamed)

Tylosaurus Nepaeolicus

Tylosaurua Proriger

 

 

 

 

[North]

10 hours ago, eboe101 said:

I have hunted the ozan for a few decades and have discussed the mosasaur fauna with a few experts. As others have said, publications are extremely limited and it was a high point in Mosasaur evolution. I took down some notes from their notes, in which they think at the least is found in tbe ozan of Texas, as they have posted on the forum and in the DPS facebook site:

 

Angolasaurus

Clidastes Propython

Globidens Alabamaensis

Halisaurus Platyspondylus

Latoplatecarpus

Mosasaurus (Conodon vs Missouriensis)

Platecarpus Coryphaeus

Platecarpus Icericus/Planfrons

Platecarpus Tympaniticus

Plioplatecarpus sp

Russellosaurine (unnamed)

Tylosaurus Nepaeolicus

Tylosaurua Proriger

 

 

 

 

Thanks for the reply.

Interesting. I did not expect Mosasaurus to be present, but if I have understood correctly, M. missouriensis has been found from older layers too, so it would be possible.

[pachy-pleuro-whatnot-odon]

On 3/17/2024 at 6:33 PM, eboe101 said:

Angolasaurus

Clidastes Propython

Globidens Alabamaensis

Halisaurus Platyspondylus

Latoplatecarpus

Mosasaurus (Conodon vs Missouriensis)

Platecarpus Coryphaeus

Platecarpus Icericus/Planfrons

Platecarpus Tympaniticus

Plioplatecarpus sp

Russellosaurine (unnamed)

Tylosaurus Nepaeolicus

Tylosaurua Proriger

 

From specimens in my own collection - albeit acquired by purchase - I can confirm presence of:

• Clidastes propython
• Globidens alabamaensis
• Latoplatecarpus sp.
• Platecarpus cf. coryphaeus
• Tylosaurus proriger
• Tylosaurus nepaeolicus

As a bonus, there's also a polycotylid plesiosaur present, though which is hard to say...

[North]

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

 

From specimens in my own collection - albeit acquired by purchase - I can confirm presence of:

• Clidastes propython
• Globidens alabamaensis
• Latoplatecarpus sp.
• Platecarpus cf. coryphaeus
• Tylosaurus proriger
• Tylosaurus nepaeolicus

As a bonus, there's also a polycotylid plesiosaur present, though which is hard to say...

Thank you for confirming.

 

Can I ask how T. nepaeolicus teeth or other material would differentiate from T. proriger?

[Praefectus]

23 hours ago, North said:

Can I ask how T. nepaeolicus teeth or other material would differentiate from T. proriger?

You know, this is actually a good question. How are you guys identifying and differentiating Ozan occurrences of T. proriger and T. nepaeolicus? Especially considering the slight chronology issue....

[Praefectus]

On 3/17/2024 at 8:54 AM, Jared C said:

informative take, I was reeled in by those lovely flashy graphics but didn’t take the time to sit with it for any reason besides ID’ing. Do you have any comprehensive tooth ID papers you’d suggest?

Oh, you know. Just start by typing "mosasaur" into Google Scholar. By the time you've read everything in the first 15ish pages of results, you will have a good start at understanding them. 

[Jared C]

14 hours ago, Praefectus said:

Oh, you know. Just start by typing "mosasaur" into Google Scholar. By the time you've read everything in the first 15ish pages of results, you will have a good start at understanding them. 

so.. "nah there aren't any"

No need to be unnecessarily condescending to somebody who's starting out in their research journey. Especially when they will be your contemporary in the field in years to come. 

[pachy-pleuro-whatnot-odon]

9 hours ago, Jared C said:

so.. "nah there aren't any"

No need to be unnecessarily condescending to somebody who's starting out in their research journey. Especially when they will be your contemporary in the field in years to come. 

 

I believe that was meant as joke 🫣

 

On 3/17/2024 at 2:54 PM, Jared C said:

informative take, I was reeled in by those lovely flashy graphics but didn’t take the time to sit with it for any reason besides ID’ing. Do you have any comprehensive tooth ID papers you’d suggest?

 

Unfortunately there aren't, a situation that undoubtedly isn't helped by the fact mosasaur researchers apply inconsistent terminology to dental morphology. I therefore  usually recommend Hornung and Reich (2014) as a base article for consistent and non-histological/externally and macroscopically observable terminology. Once you've got that down, there are a number of articles that are good to read to learn about the tooth morphologies of the major clades, although you'll need to interpret through diverging terminology to make sense of it. And also, using Hornung and Reich as reference to ground those descriptions against helps to then compare between genera and species. Having access to some clearly identified specimens for real-world comparison helps. At the same time, this is the best way I've found if learning about mosasaur tooth morphology...

[North]

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

Having access to some clearly identified specimens for real-world comparison helps.

This is very true.

It helped me a lot that when I have been able to observe tooth personally. You can rotate it around and see every angle.

 

From pictures it is sometimes hard to see what angle you are looking at and figure it in 3D.

[pachy-pleuro-whatnot-odon]

20 minutes ago, North said:

This is very true.

It helped me a lot that when I have been able to observe tooth personally. You can rotate it around and see every angle.

 

From pictures it is sometimes hard to see what angle you are looking at and figure it in 3D.

 

That's why I sometimes ask for a video to help in identification. Next best thing to actually holding a specimen IRL.

[Praefectus]

12 hours ago, Jared C said:

so.. "nah there aren't any"

No need to be unnecessarily condescending to somebody who's starting out in their research journey. Especially when they will be your contemporary in the field in years to come. 

Sorry, that was intended to be humorous. I'm poking fun at the fact that mosasaur researchers are notorious for not getting along. Read 10 papers and you'll find 10 different systems of anatomical terminology. There really isn't a good single paper that reviews dental terminology. 

 

On a more serious note, reading the totality of the literature probably IS the best method for learning these sorts of things. You'll find that while early pre-Russell '67 authors are all over the place, patterns to anatomical definitions start emerge with Lingham-Soliar in the 90s, Lindgren and Siverson in the 00s, and Bardet throughout the 2010s. But even then, caution is needed because the latter two's terminology changes between their earlier publications and their later ones (i.e., "striated" vs. "lineated", "granular" vs. "beaded", "anastomosis" vs "wrinkled" vs "thickened"... etc.). 

 

I often default to using definitions as described in Bardet et al., 2015, but Hornung and Reich, 2015 has the most terminological definitions for enamel ornamentation. Alternatively, Palci, Caldwell, and Fornaciari 2014 was fairly straightforward until the definitions were changed again in the 2021 paper you first showed. 

[Praefectus]

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

I believe that was meant as joke 🫣

 

Yeah. I try to use emojis when I'm being sarcastic .