Post Oak Creek

Yes, I'm always happy to find them, and they're not too common.

Lovely blastoid.
As has been said, Devonian blastoids are quite unusual, I have a couple of species from Spain, but none from North America.
Great find!

I have heard it said that the Sprinkle may be a tad younger than the north texas Ozan, but that's just heresay as far as I know. I think researching the context of the sprinkle vs the Ozan up north would be a good step, might explain the lack of the taxon up north

[Emended diagnosis: Serratolamna aff. khderii] I am making a minor change to the diagnosis after having had some more time to go in depth on researching these. My opinion is that these represent an undescribed species or subspecies of early Serratolamnid endemic to the Southern WIS.
 
I still believe these teeth are exact matches with those labeled Serratolamna cf. caraibaea from this Aguja article: https://doi.org/10.1016/j.cretres.2016.08.008. However, I think this morphology more closely resembles that of the contemporaneous S. khderii in the sense of https://doi.org/10.1016/j.cretres.2005.03.006 instead of S. caraibaea.
 
The Sprinkle Formation, from which the pictured teeth originate, is roughly Middle Campanian. S. khderii is known from the Middle Campanian to Early Maastrichtian of the Middle East, Western Europe, and Northern Africa. My teeth and S. khderii are smaller than Serratolamna serrata and Serratolamna caraibaea which, to my knowledge, are more or less limited to the Maastrichtian. Upon closer examination of these teeth, I noticed very short and faint striations running across the basal edge of the lingual face. This characteristic is documented in S. khderii and not the other two species. The Aguja teeth do not mention such striations, but it should be noted that their specimens are heavily eroded and could have easily lost such a minute trait. S. caraibaea and S. serrata also have more robust cusps.
 
Therefore, the affinities of both my teeth of Central Texas and those of the Aguja in West Texas seem to be closer related to S. khderii as opposed to S. caraibaea. That being said, they are not exact matches since S. khderii has a taller, narrower cusp as mentioned in the Aguja article. Compared to the S. khderii type specimen from Jordan, S. khderii seems to have skinnier root lobes as well.
 
I have mentioned before that it is very strange for these teeth to have not shown up in the NSR despite its extremely heavy collecting pressure. For whatever reason, this taxon is restricted to the Aguja and Sprinkle Formations of West and Central Texas respectively. The collecting locality of the Aguja teeth was from very shallow coastal waters and the Sprinkle Formation is quite a bit deeper than that. It seems this species/subspecies existed in at least a moderately large range of depths that one would think should include the Ozan of the NSR. I don't have any idea on how to begin trying to explain this phenomenon, but it sure is fun to wonder.
 
I hope this was interesting! If any hunters have some Sprinkle Fm teeth that look similar, feel free to share.

Very cool.  I find very young juvenile/'baby' teeth interesting.  Nice find!

That is really super.

Beautiful.

It made Tidgy shudder a bit, but that's a very nice piece.

Best thing I’ve seen all day. 

It is drilled sideways at an angle, and there is wear on the opposite side of the hole.