Hi, @bianca-serrano – What features led you to the dusky shark identification? I think that species is extant. Want me to tag in our shark experts to help you with the identification? Talk to you soon, Jen

Hi, @bianca-serrano, would you be able to take a picture of the other side of the specimen? The picture posted already does look strange even to myself, Dasyatis teeth are very small and are normally not shaped like this structure, so another view may help with a more firm identification.
Fauve

Hi, @bianca-serrano – I think your identification is incorrect. You have listed out the common modern species of stingray. I’m not sure if it’s a ray plate – it looks strange to me. I’ll tag in some Gainesville experts for you – @vperez@fauve-wilson
Talk to you soon, Jen

Hi, @bianca-serrano – do you mean allochem as the term to describe carbonate ‘grains’? Since this contains many grains, wouldn’t it simply be a coquina?