North sulphur river mosasaurs and fish

[Notidanodon]

Hi guys, I recently trade for these, and I was wondering if it was possible to assign them to a species  thanks

1.

2.

3. looks like a bit of fish rostrum?

4. best preserved one, the enamel has regular flat edges, like a polygon I guess

4. enchodus libycus?

thanks  

[Jared C]

The unfortunate thing with Mosasaurs is that that there is often great variance and morphological crossovers in their teeth. For that reason, it can be difficult to confidently assign isolated teeth to a single species.

But, it can be narrowed down to a degree. These are absolutely killer teeth btw - While I haven't hunted NSR myself I know that lots of people put in enormous effort there for less grand results than these. Congratulations. 

 

@pachy-pleuro-whatnot-odon is really the guy to go to for Mosasaur stuff, but I'll give my thoughts too.

 

For big teeth on the Ozan formation, Tylosaurus proriger is often the culprit. However, there were other big Mosasaurs swimming around at the time as well - the one I have in mind is Mosasaurus hoffmani - which can also be found in the Ozan formation. The locally famous "Onion Creek Mosasaur" is an example of one.

 

That being said, your first big tooth has some interesting characteristic curves, and may get to be specifically ID'd by someone with more knowledge than me.

 

I'm hesitant to say #3 is marine reptile. I'd put my money on fish, but I'm not sure which one.

 

I'm in love with that fourth tooth. Does it only have a carina (cutting edge) on one side?

 

Your last tooth is also an Enchodus fang, yes. I'm basing it off the characteristic curvature that the picture inferences, and it also seems there may be a shallow groove running along one side - hard to tell from the photo though.

 

 

Edited January 9, 2022 by Jared C
wrong information

[pachy-pleuro-whatnot-odon]

First off, let me say that these are indeed killer teeth! I've been trying to acquire good quality US mosasaur teeth for a couple of years now, and whenever I see one I need to jump on the opportunity, seeing as how rarely they come by and how much interest there is. Not just that, but much of the material I've seen from NSF is rather battered (as some of yours are), so that seeing such a great collection of these teeth and all in one go is really astounding. I won't hide my jealousy!

 

I pretty much agree with the general remarks @Jared C already made above: identifying mosasaur teeth as to species can be very tricky due to heterodonty. All the same, certain morphological traits, such as the direction the tooth curves in and the type of striations, can be used to identify mosasaur teeth as to their clade or genus, sometimes even to species - especially when one knows what has been found previously (which I, unfortunately, don't really). It's unfortunate that most of your teeth are so battered, as this hampers identification, but here goes:

1. Curvature of this tooth appears to be mesiodistally (anteroposteriorly), with what appear to be tertiary striae towards the base of the tooth. This suggests the tooth belongs to Tylosaurus, and based on size and specimens in my collection, likely T. proriger.
2. The labiolingual curvature of this specimen suggests this tooth is a Mosasaurus. It is too battered, however, to say anything more about it. Conclusion: Mosasaurus sp.
3. No idea, but indeed not sure whether this is a tooth, as it doesn't appear to have any enamel. Could be a fish rostrum, as proposed, but I'm not well-enough versed in fish material to help you out on that.
4. That's a real beauty! Again, labiolingual curvature, so Mosasaurus. The labial prism faces and lingual facets are a bit too prominent to outright identify this as M. hoffmannii, in which these features are typically subdued (I'd therefore much rather be inclined to go with M. lemonieri, if this species were known to occur in NSF), but with some of the teeth of M. hoffmannii being prominently prismatic this tooth belonging to that species remains an option. Conclusion: Mosasaurus cf. M. hoffmannii
5. Definitely Enchodus, but not sure about the species. However, I think E. libycus is restricted to northern Africa. Around NSF and the area formerly comprised by the Western Interior Seaway, I believe Enchodus petrosus is the more common culprit. Identification as this species would also fit well with the size (as E. petrosus is said to have been one of the largest species [source]) and how relatively straight the specimen is. See below for a comparison:

(source)

[ThePhysicist]

6 hours ago, Jared C said:

which can also be found in the Ozan formation.

Citation please. This document says that the mosasaur was found in the Navarro Fm., but I don't know if it has been renamed. It was also identified as M. maximus. 

 

In my brief communication with Mike Polcyn of SMU, it seems T. proriger is the only large mosasaur known from NSR, so the larger teeth I would comfortably call Tylosaur. As for the smaller one, it may be a different species, or a younger Tylosaur. Here are Tylosaurus teeth from NSR in the Perot museum collections for comparison (photos from the twitters of Ron Tykoski and Hillary McLean):

 

 

Dentary:

[Notidanodon]

10 hours ago, Jared C said:

The unfortunate thing with Mosasaurs is that that there is often great variance and morphological crossovers in their teeth. For that reason, it can be difficult to confidently assign isolated teeth to a single species.

But, it can be narrowed down to a degree. These are absolutely killer teeth btw - While I haven't hunted NSR myself I know that lots of people put in enormous effort there for less grand results than these. Congratulations. 

 

@pachy-pleuro-whatnot-odon is really the guy to go to for Mosasaur stuff, but I'll give my thoughts too.

 

For big teeth on the Ozan formation, Tylosaurus proriger is often the culprit. However, there were other big Mosasaurs swimming around at the time as well - the one I have in mind is Mosasaurus hoffmani - which can also be found in the Ozan formation. The locally famous "Onion Creek Mosasaur" is an example of one.

 

That being said, your first big tooth has some interesting characteristic curves, and may get to be specifically ID'd by someone with more knowledge than me.

 

I'm hesitant to say #3 is marine reptile. I'd put my money on fish, but I'm not sure which one.

 

I'm in love with that fourth tooth. Does it only have a carina (cutting edge) on one side?

 

Your last tooth is also an Enchodus fang, yes. I'm basing it off the characteristic curvature that the picture inferences, and it also seems there may be a shallow groove running along one side - hard to tell from the photo though.

 

 

Thanks so much   Yes they are great for sure, i was lucky to acquire them in a trade here on the forum   #4 is in great condition i agree, the cutting edge runs down all of one side and only on the tip of the other

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

First off, let me say that these are indeed killer teeth! I've been trying to acquire good quality US mosasaur teeth for a couple of years now, and whenever I see one I need to jump on the opportunity, seeing as how rarely they come by and how much interest there is. Not just that, but much of the material I've seen from NSF is rather battered (as some of yours are), so that seeing such a great collection of these teeth and all in one go is really astounding. I won't hide my jealousy!

 

I pretty much agree with the general remarks @Jared C already made above: identifying mosasaur teeth as to species can be very tricky due to heterodonty. All the same, certain morphological traits, such as the direction the tooth curves in and the type of striations, can be used to identify mosasaur teeth as to their clade or genus, sometimes even to species - especially when one knows what has been found previously (which I, unfortunately, don't really). It's unfortunate that most of your teeth are so battered, as this hampers identification, but here goes:

1. Curvature of this tooth appears to be mesiodistally (anteroposteriorly), with what appear to be tertiary striae towards the base of the tooth. This suggests the tooth belongs to Tylosaurus, and based on size and specimens in my collection, likely T. proriger.
2. The labiolingual curvature of this specimen suggests this tooth is a Mosasaurus. It is too battered, however, to say anything more about it. Conclusion: Mosasaurus sp.
3. No idea, but indeed not sure whether this is a tooth, as it doesn't appear to have any enamel. Could be a fish rostrum, as proposed, but I'm not well-enough versed in fish material to help you out on that.
4. That's a real beauty! Again, labiolingual curvature, so Mosasaurus. The labial prism faces and lingual facets are a bit too prominent to outright identify this as M. hoffmannii, in which these features are typically subdued (I'd therefore much rather be inclined to go with M. lemonieri, if this species were known to occur in NSF), but with some of the teeth of M. hoffmannii being prominently prismatic this tooth belonging to that species remains an option. Conclusion: Mosasaurus cf. M. hoffmannii
5. Definitely Enchodus, but not sure about the species. However, I think E. libycus is restricted to northern Africa. Around NSF and the area formerly comprised by the Western Interior Seaway, I believe Enchodus petrosus is the more common culprit. Identification as this species would also fit well with the size (as E. petrosus is said to have been one of the largest species [source]) and how relatively straight the specimen is. See below for a comparison:

(source)

Thankyou so much for your help you really know your stuff for no.2 would size not be diagnostic enough? n.4 shows all the details very nicely,and i agree on the enchodus, thanks once again 

3 hours ago, ThePhysicist said:

Citation please. This document says that the mosasaur was found in the Navarro Fm., but I don't know if it has been renamed. It was also identified as M. maximus. 

 

In my brief communication with Mike Polcyn of SMU, it seems T. proriger is the only large mosasaur known from NSR, so the larger teeth I would comfortably call Tylosaur. As for the smaller one, it may be a different species, or a younger Tylosaur. Here are Tylosaurus teeth from NSR in the Perot museum collections for comparison (photos from the twitters of Ron Tykoski and Hillary McLean):

 

 

Dentary:

Some lovely material there, thanks for sharing

[Praefectus]

4 hours ago, ThePhysicist said:

Citation please. This document says that the mosasaur was found in the Navarro Fm., but I don't know if it has been renamed. It was also identified as M. maximus. 

Mosasaurus maximus is what the paleontologist Edward Drinker Cope called American occurrences of Mosasaurus hoffmannii. The two species have since been synonymized with M. hoffmannii taking priority. Another source for this is Dale Russell's 1967 monograph Systematics and Morphology of American Mosasaurs. 

 

I second @pachy-pleuro-whatnot-odon's identifications:

1) Tylosaurus cf. proriger  --- It has the signature tylosaur meat-hook shape.

2) Mosasaurus sp. 

3) Fish

4) Mosasaurus cf. hoffmannii  --- Assuming the tooth is Maastrichtian or Late Campanian in age. Mosasaurus missouriensis (synonymous M. horridus) if older. Prismatic enamel points towards Mosasaurus.

5) Fish

[pachy-pleuro-whatnot-odon]

4 hours ago, will stevenson said:

for no.2 would size not be diagnostic enough?

 

Unfortunately not, since on the one hand a lot of size variation is known to occur within single species of mosasaurs (teeth would've kept growing as the mosasaur grew and there are strong indications that mosasaurs kept growing all through their lives), while on the other research into juvenile is still pretty much in its infancy, from what I gather. As such, different species within a single genus have been proposed (and debunked) as belonging to juveniles and adults of a single species respectively, while it's also very well possible that juveniles would have had different feeding patterns, and therefore slightly different dentition from adults. In other words, we can't be sure of the size spectrums of the teeth of different mosasaur species, and, as such, without other morphological features to guide us, it'll be hard to say which species a tooth belongs to. Don't forget mosasaurs are heterodontous too, further complicating this matter.

[Jared C]

16 hours ago, ThePhysicist said:

This document says that the mosasaur was found in the Navarro Fm., but I don't know if it has been renamed. It was also identified as M. maximus

Mosasaurus maximus is a junior synonym to Mosasaurus hoffmani, meaning they're the same species. The animal was discovered in Europe and given the name hoffmani, and when it was also discovered in america, it was given the name maximus. Technically speaking, I guess it's better to use hoffmani, since that was the first name given.

 

Also, yes - I was mistaken - it was indeed found in the Navarro group, not in the Taylor group - I got mixed up. I'll make that correction

[Praefectus]

On 1/8/2022 at 11:32 PM, Praefectus said:

Mosasaurus maximus is what the paleontologist Edward Drinker Cope called American occurrences of Mosasaurus hoffmannii. The two species have since been synonymized with M. hoffmannii taking priority. Another source for this is Dale Russell's 1967 monograph Systematics and Morphology of American Mosasaurs. 

 

I second @pachy-pleuro-whatnot-odon's identifications:

1) Tylosaurus cf. proriger  --- It has the signature tylosaur meat-hook shape.

2) Mosasaurus sp. 

3) Fish

4) Mosasaurus cf. hoffmannii  --- Assuming the tooth is Maastrichtian or Late Campanian in age. Mosasaurus missouriensis (synonymous M. horridus) if older. Prismatic enamel points towards Mosasaurus.

5) Fish

 

I just happened across this thread again by chance and I noticed I got the IDs wrong. 2 and 4 are also Tylosaurus. I mistook heterodonty and preservation with speciation when I wrote the original comment.