Pterosaur or Fish Tooth? Pawpaw Fm

[Mikrogeophagus]

Took another trip out to explore the other half of the Pawpaw site about a week ago and came away with some great finds I will be posting soon. Most of the things I brought back weren't too hard to pin an ID on. This little guy has been giving me some trouble though. I know that pterosaur teeth are found in the Pawpaw a bit more often than other formations around here. This preconception may be clouding my judgement a bit, but I have a suspicion that this could be a pterosaur instead of a fish tooth (enchodus). I haven't found many teeth in the Pawpaw so far, so I'm not well acquainted with how enchodus or other fish are preserved in this formation. Some of the photos below come from my new stereomicroscope which seems to work pretty well, but I am still figuring it out (like how to get rid of the messed up timestamp).

 

I've ruled out protospyraena as I believe they have two edges around their circumference whereas my specimen has only one.

 

This specimen is 13mm and brown. It has one non-serrated edge and is smooth the rest of the circumference. There is some natural wear on the tip. The bottom of the tooth is fragmented which allows us to take a look a bit in the interior. It seems the tooth is hollowed out where I believe the pulp cavity once was. Not sure if this feature aligns with pterosaur or fish. The base of the tooth that is present seems to gradually flatten.

 

If y'all know any pterosaur experts on here, feel free to ping them. 

 

Without further ado, here are some pics:

 

 

 

Thanks!

[Troodon]

Have you considered this being the crown of rostral spine of Ischyrhiza, missing its base?

 

 

[Carl]

Could also be Xiphactinus,. And I can't easily rule out Enchodus. Pretty hard to tell.

[Mikrogeophagus]

I actually misremembered enchodus as being single-edged. Looking back at some in my collection, they are double-edged so I'm ruling that out.

 

@Carl @Troodon  Ischyrhiza and xiphactinus are both really good suggestions. I don't have x-fish in my collection already, so it's difficult to compare, but looking online I see some pretty similar stuff. I hadn't thought of it before since I thought x-fish teeth should be much larger, but now I see a small one from the pawpaw on north texas fossils. Ischyrhiza is a possibility, but I'm having some difficulty seeing this as being the same. My ischyrhiza from moss creek seems to be rounder around the base of the crown and take on an overall different shape. So, I think x-fish is what I'll go with unless someone disagrees.

[Al Dente]

This photo from your trip report shows a different view. Is that an indentation along the length of the tooth or is it an artifact of the lightning?
 

 

 

Edited January 6, 2023 by Al Dente

[Mikrogeophagus]

There is a very shallow indentation accented by the light along about the bottom third of the tooth @Al Dente