Two Parotodus Benedenii teeth, one of which looks quite weird

[Psittacosaurus]

Parotodus benedenii was a giant pelagic shark that appeared in the Oligocene and went extinct in the Pliocene. Most other larger shark teeth are triangular with (at least one of) the sides of its crown blades pretty much straight, but not this one. The teeth of Parotodus are distinctive with a very thick and robust root, resembling large and curved hooks.  This species is purely pelagic, which makes its fossils much rarer than most other giant sharks (though I don't think it's as rare as most sellers want you to believe), hence virtually no paleo art illustrations are available for this genus.

 

My two Parotodus benedenii teeth:

 

The first one comes from the Pungo River Formation in North Carolina.

Pretty standard tooth, preserved in an environment with high concentrations of phosphate. Phosphate deposits are created through the chemical precipitation of phosphate from seawater in nutrient-rich regions that contain animal remains. This is why you see lots of marine fossils in these phosphate deposits.

However, its preservation setting might have changed from phosphate to marine environments or vice versa midway through the fossilization process, as the root does not look like a phosphate-preserved root but rather a very sturdy, pelagically acquired root.

 

 

 

Then there is this second tooth which I can't figure out. Its root is a lot less robust and much thinner, but not as thin as the roots from other sharks like the Great White or Cosmopolitodus planus (or whatever genus it belongs to now since its taxonomy changes just about as often as Spinosaurus life restorations). If you look at the previous Benedenii, you'll see a little space between the root and where the enamel begins, similar to bourlette from Otodus teeth. But this next one barely has this little space. I tried to figure out the tooth position but also couldn't get any results.