Flat Dermal Denticle

[Shellseeker]

This is a 1st for me, a denticle that is this thin, this large.  I dimly recall hearing somewhere that these came from sharks, not stingrays. Let's see if some more knowledgeable than I concur.  @Al Dente @MarcoSr@siteseer

 

[Al Dente]

Jack- Yours is pretty thin but it is from a stingray, probably Dasyatis centroura. Here’s a thread with a similar one-http://www.thefossilforum.com/index.php?/topic/79033-fossil-scute/

[Shellseeker]

1 hour ago, Al Dente said:

Jack- Yours is pretty thin but it is from a stingray, probably Dasyatis centroura. Here’s a thread with a similar one-http://www.thefossilforum.com/index.php?/topic/79033-fossil-scute/

Thank you. 

On my speculation of large, thin denticles associated with sharks,  is that myth ?  Certainly should be if you have not found them.

[MarcoSr]

2 hours ago, Shellseeker said:

Thank you. 

On my speculation of large, thin denticles associated with sharks,  is that myth ?  Certainly should be if you have not found them.

 

Yes, large (except for Bramble sharks) that is a myth.  Most shark species have dermal denticles which are less than 1 mm in length.  Bramble sharks (Echinorhinus) have the largest shark dermal denticles that I'm aware of.

 

 

Echinorhinus brucus Compagno 1984

 

 

 

 

 

 

Echinorhinus cookei Compagno 1984

 

 

 

 

 

 

 

Check out the below link to see examples of shark dermal denticles/placoid scales.

 

 

http://www.thefossilforum.com/index.php?/topic/92865-shark-skin-with-placoid-scalesray-skin-with-dermal-denticles/&tab=comments#comment-1022303

 

 

Marco Sr.

[Boesse]

I've got a paper on these gigantic dermal elements from large stingrays coming out in the coming weeks - some of these gigantic denticles/bucklers may represent stingrays up to 3-4 meters in width!