More Treasures from the Cretaceous Anthills - Domed Teeth

[Arizona Chris]

Hi all,

 

As we continue to wash, sieve and go through one teaspoon at a time our gravels from the sides of giant ant hill mounds from the Twowells Tongue of the Dakota, we are finding some very exciting microfossils!  As you recall, we found ourselves on the top of a large rounded hilltop a few months back with very rare limestone on its cap.  Most sediment from this formation is either a yellow sandstone, or shale.  The Ants did all the work - They brought up pieces of material from the depths of the usual stuff, mostly small gravel pieces and sand.  But mixed in has been a plethora of microfossils.  Besides the tons of giant forams I posted last time, we have hordes of shark and fish teeth.  Can you imagine a red fire ant about 1/4" long carrying a perfect fossilized shark tooth out of its burrow?  (yes they bite!)

 

Here are some representative of what some us were calling "Ray or Skate teeth".  IVe put them under the microscope at 10x and did a dark field illumination.  Most are top up and a few bottom up so you can see both sides.  They are roughly 2-3mm in size and are a bit oblong.  Most are flat topped domed, but many are more pointy and spherical in shape.  My thoughts are some sort of pavement crushing shark which ate molluscs?  What do you think, I don't have much experience with fish teeth, but we are sure finding some beauties!

[StevenJD]

could they be pycnodont teeth?

[Troodon]

Look a bit like Paralbula fish teeth out of the hell creek formation 

[Al Dente]

23 minutes ago, StevenJDennis said:

could they be pycnodont teeth?

 

I think pycnodont is a good possibly  for these teeth. I'm looking forward to seeing more anthill finds.

[Arizona Chris]

Wow, I had to look up pycnodont on wikipedia.  The teeth are up to 3mm long, is that within the size range for these?

 

Here is what wiki had:

 

Pycnodontiformes is an extinct order of bony fish. The group evolved during the Late Triassic and disappeared during the Eocene. The group has been found in rock formations in Africa, Asia, Europe, North and South America.^[1]

The pycnodontiforms were small to middle-sized fish, with laterally-compressed body and almost circular outline.^[2]

Pycnodontiform fishes lived mostly in shallow-water seas. They had special jaws with round and flattened teeth,^[3] well adapted to crush food items.^[2] One study links the dentine tubules in pycnodont teeth to comparable structures in the dermal denticles of early Paleozoic fish.^[4] Some species lived in rivers and possibly fed on molluscs and crustaceans.^[5]