North Sulfur River - August 29th

[BudB]

The North Sulfur River finally got some rain last week, and I headed out there yesterday morning to see what I could find. I was hoping there had been enough sun that it wasn't still a muddy mess, but that wasn't the case. It was a tough slog, hiking through all that mud. It made fossils tough to spot too, and I didn't find a lot. But I still enjoyed my day in the river. This photo shows what much of the riverbed looked like. Are those footprints from a large bird or small dinosaur?

 

 

[BudB]

Some in situ photos from the day. That last fossil wasn't too tough to spot.

 

[BudB]

This mosasaur vert was the find of the day. It's smaller, and not in as good of shape as the big one I found earlier this year, but I still thought it was a beauty. Here are four views of it.

 

[BudB]

This second mosasaur vert has had material split off of it, on both sides. It makes you wonder just how many mosasaur verts disintegrate to the point of being unrecognizable as they tumble on these gravel bars.

 

[BudB]

At the very far end of where I hike in this part of the river is a spot on a gravel bar with some better washed tiny gravel. I always do some kneepad hunting in this spot. It's been a good spot to find teeth. But the slow slog through yesterday's mud made me arrive at this spot so late, it was really past time to turn around and head back. So I only hunted on kneepads for a short time. But I still found two teeth. Even when I spend a lot of time on kneepads in the NSR, I still never seem to find more than two teeth the same day. So I'm calling yesterday's short kneepad hunt a success.

 

I found two teeth, four hamulus worm tubes, and I'm not sure what that other piece is. It looks like it may be two tiny fish verts stuck together.

 

[BudB]

Here is the shark tooth. I haven't tried to ID it yet. It is certainly in better shape than most of the shark teeth I find at NSR. Both cusplets are intact.

 

[BudB]

Here is the enchodus fang. It's small, but more complete than most of the enchodus teeth I find.

 

[Darktooth]

The sharktooth is a Cretolamna species but unsure which one. Nice finds.

[Jared C]

3 hours ago, BudB said:

Are those footprints from a large bird or small dinosaur?

 

Same thing, if you think about it 

 

Nice Cretolamna 

[GPayton]

I'm pretty sure Cretolamnna appendiculata is the ID for your shark tooth. Although I've often wondered why the teeth from that species found in the North Sulphur look so much more robust than the ones I've found from the same species in Waco in the Grayson formation. 

[BudB]

5 hours ago, GPayton said:

I'm pretty sure Cretolamnna appendiculata is the ID for your shark tooth. Although I've often wondered why the teeth from that species found in the North Sulphur look so much more robust than the ones I've found from the same species in Waco in the Grayson formation. 

Funny how each area has its own characteristics, isn't it?

[Jared C]

5 hours ago, BudB said:

Funny how each area has its own characteristics, isn't it?

Right? @ThePhysicist has a theory (which in my opinion is well founded) that the Texas Cretodus "crassidens" aren't actually crassidens, and that they're still instead a species that demands their own description. There are a lot of regional differences that seem to go undescribed in sharks. 

 

I know little about Cretolamna in general, but I noticed the same thing that @GPayton pointed out after you posted, and could't help by remember that the Ozan Cretolamna I've seen further south also look a lot different. There's another species of Cretolamna, (Cretolamna bryanti), that was relatively recently described in Alabama's middle campanian Moorveille chalk (roughly equivalent to the Ozan), but it looks much different than these. There's another Campanian Cretolamna, Cretolamna sarcoportheta, that looks very similar to our Ozan occurences, but I can't see a reference to it outside of Europe. Furthermore, Siverson, M. & Lindgren, J. & Newbrey, M.G. & Cederström, P. & Cook, T.D. (2015) mention it's an early Campanian species. Look how nicely it compares though.

(Siverson's paper below)

https://www.researchgate.net/publication/271354775_Late_Cretaceous_Cenomanian-Campanian_mid-palaeolatitude_sharks_of_Cretalamna_appendiculata_type/figures?lo=1

 

@ThePhysicist, I'm curious about your thoughts on our Ozan Cretolamna?

 

[ThePhysicist]

On 9/2/2022 at 10:52 PM, Jared C said:

@ThePhysicist, I'm curious about your thoughts on our Ozan Cretolamna?

It's a really nice tooth!

...

Like has been done historically, I've assigned most of these Cretalamna teeth from NTX to C. appendiculata, and to an amateur collector it's easy to see why that's been the case since these teeth are so darn similar. 

 

In Siversson et al. (2015) (the paper you reference), they divide C. appendiculata into three "groups" (C. appendiculata-type, C. hattini-type, and C. borealis-type). I believe this tooth is in the C. appendiculata group (includes C. appendiculata, C. sarcoportheta) given the lack of strong posteriorly-oriented recurvature in the main cusp and asymmetry in the root. The authors also say a distinguishing feature between the two species is in general a more pronounced lingual root protuberance in C. sarcoportheta for comparable positions, but the difference that I note between the species in posterior teeth is so slight that I might not be able to distinguish them. @BudB, can we see a side-on view of your tooth?

 

C. appendiculata

C. sarcoportheta

 

On 9/2/2022 at 10:52 PM, Jared C said:

There's another Campanian Cretolamna, Cretolamna sarcoportheta, that looks very similar to our Ozan occurences, but I can't see a reference to it outside of Europe.

This could be attributed to the fact that the species was named recently; as I said, historically all these teeth were lumped into C. appendiculata.

 

On 9/2/2022 at 10:27 AM, GPayton said:

I'm pretty sure Cretolamnna appendiculata is the ID for your shark tooth. Although I've often wondered why the teeth from that species found in the North Sulphur look so much more robust than the ones I've found from the same species in Waco in the Grayson formation. 

Robust in what way? Do you have several teeth from similar positions to compare? Just curious; one factor could be ontogeny (like in modern white sharks the trend is gracile to robust), but if we have several teeth that show a clear bimodal grouping that coincides with the locality, that could strike down that hypothesis or it could suggest something like a nursery etc.

On 9/2/2022 at 10:52 PM, Jared C said:

@ThePhysicist has a theory (which in my opinion is well founded) that the Texas Cretodus "crassidens" aren't actually crassidens, and that they're still instead a species that demands their own description. There are a lot of regional differences that seem to go undescribed in sharks.

I've yet to look into what's known about Cretodus's ontogeny (if anything), and what could be done to possibly rule it out as a cause for the differences we see. Likely nothing will happen until we get a sizeable tooth set. 

[Jared C]

11 hours ago, ThePhysicist said:

This could be attributed to the fact that the species was named recently; as I said, historically all these teeth were lumped into C. appendiculata.

 

Gotcha, that makes sense

 

What threw me of off most was that Siversson's paper insists that C. appendiculata (not generally the "C.appendidiculata type", but the true type species, Cretolamna appendiculata) seems largely restricted to the Turonian, of Europe. He states that as it stands, it can only be positively identified from the early Turonian of northern france and its type area in england (a quarry that spans the cenomanian to early coniacian)

 

C. sarcoportheta is implied to be a more derived Campanian counterpart to C. appendiculata in the paper, and he makes those comparisons under the "remarks" for the C. appendiculata section. 

 

So - it seems that you're right that perhaps geographic range of both should be put aside here. Maybe we should consider temporal range. I'm thinking that our Ozan Cretolamna species, just judged off of it's temporal range, might have a higher probability of being C. sarcopatheta

 

Nifty

[BudB]

On 9/4/2022 at 10:46 PM, ThePhysicist said:

 @BudB, can we see a side-on view of your tooth?

 

 

 

Here are views of each side of the tooth.

 

[digit]

On 8/30/2022 at 5:51 PM, BudB said:

Are those footprints from a large bird or small dinosaur?

Yes.

 

Looks like a fun (though slippery) hunt. Wish Florida's fossil record extended back to the Cretaceous. I do seem to have a predilection for shark teeth with side cusps.

 

 

Cheers.

 

-Ken

[ThePhysicist]

On 9/6/2022 at 11:48 AM, BudB said:

Here are views of each side of the tooth.

Thanks, since the lingual side appears to be damaged, Siversson et al. (2015) would suggest that ID to species isn't possible.

 

On 9/5/2022 at 9:56 AM, Jared C said:

So - it seems that you're right that perhaps geographic range of both should be put aside here. Maybe we should consider temporal range. I'm thinking that our Ozan Cretolamna species, just judged off of it's temporal range, might have a higher probability of being C. sarcopatheta

Could be...

[Notidanodon]

Yeah cretalamna appendiculata is what one might call a waste bucket taxon there is a huge variety in these teeth and hopefully someone will try and rectify it