Partial Eagle Ray Dental Plates?

[Bronzviking]

Hi, I found these 2 unusual little pieces on a Tampa Bay beach in Florida. They are roughly 1 x 1 inches. At first I thought pottery shards or some seashell mold and put them in a box. I just saw a photo that they resemble, labeled Ray Dental plate. (brown photo) I attached 3 photos front and back of my specimen. What do you think?

[PaleoNoel]

I'm gonna say it's not a ray dental plate because it appears to lack the defining features. It certainly is odd looking and I don't think it's bone, my guess would be some type of invertebrate trace or impression in the limestone.

[Coco]

Hi,

 

This is not at all the structure of ray dental plates.

 

Coco

[hemipristis]

They appear to be impressions in limestone (var. packstone or grainstone) rather than the phosphate of a dental plate. 

[Bronzviking]

5 hours ago, hemipristis said:

They appear to be impressions in limestone (var. packstone or grainstone) rather than the phosphate of a dental plate. 

What do you think made these impressions? The grooves seem so uniformly spaced.

[Bronzviking]

Hey Guys from Florida can you please take a look? What do you think made these impressions, any ideas? Thanks. @Shellseeker @Plantguy

[Plantguy]

Tough question but I think your initial impression might be correct--that it's a mold of some shell. I agree and dont think its a ray dental plate as the others have suggested.

 

I dont know which one but there are a number of different critters that have ribs on/in their shells that may have a shot at creating an impression something like your finds...Some of the Pecten ribs are pronounced and have a squared off look to them but they do show very faint growth lines when not tumbled in the surf. Yours look pretty worn so I'm not sure that sort of detail remains. Some of the columellar folds also on the gastropod columellas have a similar squaring. Here's a picture of some of what I'm describing...If you have some clay you might be able to pick up some details by trying to make a cast of those lines....again the beach has done a pretty good tumbling/wearing things down. 

Hoping one of the others might recognize something more specific and can offer some certainty--I will admit to be just guessing at this stage as the fossil trace is worn and incomplete and its just not shouting at me what it is, but it's nonetheless interesting! 

Regards, Chris 

[Shellseeker]

On 4/3/2021 at 8:41 PM, Bronzviking said:

Hey Guys from Florida can you please take a look? What do you think made these impressions, any ideas? Thanks. @Shellseeker @Plantguy

In Florida,  we have some really interesting fossil environments. We have the oceans and seashells going back tens of millions of years, we have the fossils of the creatures that inhabited those oceans, and we have land mammals over the last 30 or so million years. Sometimes very fragile fossils are pristine, and sometimes very durable fossils are worn beyond recognition.

 

You have brought a different perspective and questioning mind to fossils that I have glossed over,  Keep it up.  Sooner or later , you will discover an ID where others might not have.

 

Like others, I think the most likely answer is that these are impressions in limestone. @Plantguy is pretty good at this and he can see one possibility is the internal spirals of some locally common gastropods. I am thankful for his presentation style, and agree that one of the more likely possibilities is a shell impression on limestone. There are tons of all this stuff laying around and I see numerous similar examples of grooves in what appears to be limestone.

 

I am one of those humans fossil hunters who much prefer specific IDs rather than "maybe"s. However, I have learned to live with not knowing. 

 

 

[Bronzviking]

On 4/4/2021 at 12:49 AM, Plantguy said:

Tough question but I think your initial impression might be correct--that it's a mold of some shell. I agree and dont think its a ray dental plate as the others have suggested.

 

I dont know which one but there are a number of different critters that have ribs on/in their shells that may have a shot at creating an impression something like your finds...Some of the Pecten ribs are pronounced and have a squared off look to them but they do show very faint growth lines when not tumbled in the surf. Yours look pretty worn so I'm not sure that sort of detail remains. Some of the columellar folds also on the gastropod columellas have a similar squaring. Here's a picture of some of what I'm describing...If you have some clay you might be able to pick up some details by trying to make a cast of those lines....again the beach has done a pretty good tumbling/wearing things down. 

Hoping one of the others might recognize something more specific and can offer some certainty--I will admit to be just guessing at this stage as the fossil trace is worn and incomplete and its just not shouting at me what it is, but it's nonetheless interesting! 

Regards, Chris 

Thanks Chris for the awesome detailed diagram. I was thinking Pectin also but the columellar folds are a good possibility too. I took some clay and made some impressions to see if this would help. The separations seem wider and slightly curved than the ribs on the scallop shell. Do these images change anything? I guess we can say unknown impression but I thought they were interesting.

[Bronzviking]

On 4/5/2021 at 9:45 AM, Shellseeker said:

In Florida,  we have some really interesting fossil environments. We have the oceans and seashells going back tens of millions of years, we have the fossils of the creatures that inhabited those oceans, and we have land mammals over the last 30 or so million years. Sometimes very fragile fossils are pristine, and sometimes very durable fossils are worn beyond recognition.

 

You have brought a different perspective and questioning mind to fossils that I have glossed over,  Keep it up.  Sooner or later , you will discover an ID where others might not have.

 

Like others, I think the most likely answer is that these are impressions in limestone. @Plantguy is pretty good at this and he can see one possibility is the internal spirals of some locally common gastropods. I am thankful for his presentation style, and agree that one of the more likely possibilities is a shell impression on limestone. There are tons of all this stuff laying around and I see numerous similar examples of grooves in what appears to be limestone.

 

I am one of those humans fossil hunters who much prefer specific IDs rather than "maybe"s. However, I have learned to live with not knowing. 

 

 

Thanks Jack for you compliment and your knowledge it's always appreciated.

[Plantguy]

I think this may be a scenario where they may be just too incomplete and worn to come up with anything definitive but I'm still curious.. elongated rib shape/impressions that seem to parallel each other that also may have flat sides/walls and also differ in thicknesses. 

 

@MikeR Maybe Mike might sees something.

 

Last resort is to throw a quick note and some pics up to Dr. Roger Portell in Gainesville and see if he can add any insight... portell@flmnh.ufl.edu. 

 

Regards, Chris 

[hemipristis]

On 4/2/2021 at 12:54 AM, Bronzviking said:

What do you think made these impressions? The grooves seem so uniformly spaced.

now that part I don't know.  I like the shell mold idea.  It's common for carbonate sediment and shell hash to infill gastropods and solidify, forming a rock called coquina, which can be more durable than the shell in which it was deposited. Geochemistry is a funny thing.

Edited April 12, 2021 by hemipristis