Post Oak Creek micro shark tooth

[TRout]

I found this tiny tooth while searching through some matrix collected from Post Oak Creek in Sherman, Texas. I believe the formation there is the Eagle Ford Group, Cretaceous. For scale, the grid in the pictures is 5x5mm, the tooth measures just under 3mm. I've been looking into Palaeogaleus and Galeorhinus, but neither seem to fit (I don't see any bulge with a crown that overhangs the root). Are either of these even known from this formation? Any thoughts on the ID of this tooth are appreciated, thanks!

 

[ThePhysicist]

Wow. I've been picking POC micromatrix for three years and haven't seen a tooth like this. I would say the best candidate at the moment is indeed a tope. There isn't a comprehensive faunal list for the EFG, but Galeorhinus/Paleogaleus is apparently known from the Lower Turonian onwards.

55 minutes ago, TRout said:

(I don't see any bulge with a crown that overhangs the root)

This could be a result of weathering, a common affliction for these teeth. The strong distal inclination of the cusp, the presence of large, triangular serrations only on the distal edge are pretty unique features (especially in the Cretaceous) that whittle the possibilities down to tope, new species, or some species that only a handful of specialists know about. I opt for the foremost. 

@MarcoSr@Al Dente

[Al Dente]

6 hours ago, TRout said:

(I don't see any bulge with a crown that overhangs the root).

It looks like a bit of enamel bulge here. It looks eroded across most of the tooth. 
 

 

[MarcoSr]

6 hours ago, ThePhysicist said:

Wow. I've been picking POC micromatrix for three years and haven't seen a tooth like this. I would say the best candidate at the moment is indeed a tope. There isn't a comprehensive faunal list for the EFG, but Galeorhinus/Paleogaleus is apparently known from the Lower Turonian onwards.

This could be a result of weathering, a common affliction for these teeth. The strong distal inclination of the cusp, the presence of large, triangular serrations only on the distal edge are pretty unique features (especially in the Cretaceous) that whittle the possibilities down to tope, new species, or some species that only a handful of specialists know about. I opt for the foremost. 

@MarcoSr@Al Dente

 

1 hour ago, Al Dente said:

It looks like a bit of enamel bulge here. It looks eroded across most of the tooth. 
 

 

 

I really can't add any more than what has already been said.  I agree that the tooth features of this tooth are pretty unique for a Cretaceous shark tooth.  I agree with Eric that it looks like the bulge may have been removed by enamel erosion.  If the tooth isn't Galeorhinus or Paleogaleus, then I really don't know what else it might be.

 

Marco Sr.